Documents published in 2005 : Scipedia

Future en route air traffic control workstation: back to basics
B. Willems

Collection of open conferences in research transport (2005). Vol. 2005, 70

Abstract
The expected increase of air traffic by at least 33% by 2015 to 2020 requires more than an evolutionary change from the way air traffic controllers work today in more than an evolutionary manner. One way to do this is to free up individual air traffic controller physical and mental resources. If controllers can apply the increase in available resources to air traffic control, we expect that they have more capacity to absorb an increase in air traffic. To make these resources available we use human factors principles to integrate available data and provide that data to controllers in an efficient presentation format. We report on the development of a concept software platform that integrates data obtained from existing automation tools with available National Airspace System (NAS) data. The integration takes place at the human computer interface and attempts to make that interface easy to use by applying human factors principles and leveraging existing air traffic controller expertise. We discuss why we must present National Airspace data in an integrated manner. We also present how we intend to assess if our approach has succeeded in freeing individual air traffic controller resources.
Abstract
The expected increase of air traffic by at least 33% by 2015 to 2020 requires more than an evolutionary change from the way air traffic controllers work today in more than [...]
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An Integrated Engineering Model for Prediction of Strain Demands in Pipelines Subject to Frost Heave
B. Hazen, J. Hart, J. Zhou, G. Craig

Collection of open conferences in research transport (2006). Vol. 2006, 76

Abstract
Long distance pipelines are actively pursued by the industry to transport natural gas from remote arctic regions to markets. A chilled gas pipeline is one of the options to minimize the environmental impact resulting from operation of such pipelines. When a chilled gas pipeline crosses discontinuous permafrost areas, differential frost heave can occur. The result is pipe being subjected to potentially high strains, primarily in the axial direction. Reliable prediction of strain demands is one of the key components for a strain-based design process and it is essential for both ensuring pipeline integrity and facilitating life-cycle cost optimization for the design and maintenance of pipelines. The prediction of strain demands resulting from frost heave of chilled gas pipelines involves three fundamental engineering analysis processes. They are gas hydraulic analysis, geothermal analysis and pipeline structural analysis. Not only are these three processes complex, they are also mutually interdependent. To reliably predict strain demands and fully capture the interactions among these processes, TransCanada Pipelines Ltd. (TransCanada) and its partners developed an integrated engineering model on the basis of three well established programs for the three individual engineering processes. This paper will briefly review the integrated model for strain demand prediction.Copyright © 2006 by ASME
Abstract
Long distance pipelines are actively pursued by the industry to transport natural gas from remote arctic regions to markets. A chilled gas pipeline is one of the options to [...]
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Analyzing the Runway Capacity of Complex Airports
W. Swedish, P. Kuzminski, J. Barrer

Collection of open conferences in research transport (2005). Vol. 2005, 69

Abstract
This paper describes a simulation modeling system we have developed, called Airport Capacity Analysis Through Simulation (ACATS). Airport capacity, in the sense of the average throughput obtainable during periods of high demand, is determined directly by simulating a constant flow of arrivals and departures for hundreds of hours. The user interface for ACATS provides a fast way to set up the elements of the airport that are essential for calculating runway capacity. It also supports the use of Air Traffic Control (ATC) separation rules that may become feasible as technology improves. The software in the user interface automatically converts the data for any airport into a standardized set of files that are then processed by the ACATS simulation software. At the core of the ACATS software is a simulation engine that is common to all airport analyses. That means that the simulation is driven by data representing the ATC rules, runway layout, and demand characteristics. The output of ACATS includes an animation of the simulation, statistics about the observed throughput, and a set of graphical analysis charts. The animation and graphical results produced by ACATS are important tools in explaining the analysis to the end user and in validating the results of the simulation. This paper will describe 1) the ACATS user interface tool that permits the user to easily describe the problem, 2) the ACATS simulation module, and 3) the methodology that governs the ACATS algorithms.
Abstract
This paper describes a simulation modeling system we have developed, called Airport Capacity Analysis Through Simulation (ACATS). Airport capacity, in the sense of the average [...]
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Behavior-Consistent Within-Day Traffic Routing under Information Provision
A. Paz, S. Peeta

Collection of open conferences in research transport (2006). Vol. 2006, 71

Abstract
The problem addressed here involves a central controller seeking to optimize traffic network performance under real-time routing information provision to drivers while explicitly accounting for drivers' likely reactions towards the information. A fuzzy control approach is used to identify the behavior-consistent information-based control strategies. Experiments are performed to evaluate the effectiveness of the fuzzy controller. The results show the importance of incorporating driver behavior in the identification of the information strategies. Significant differences in terms of total system travel time can be obtained when the behavior-consistent approach is compared to traditional approache
Abstract
The problem addressed here involves a central controller seeking to optimize traffic network performance under real-time routing information provision to drivers while explicitly [...]
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Propagation in Soil of Vibrations due to a Tramway
M. Maldonado, D. Le Houedec

Collection of open conferences in research transport (2006). Vol. 2006, 70

Abstract
International audience; Tramway traffic may produce vibrations propagating in soil, which implies vibration annoyance for people living or working in neighbouring buildings. Thus vibration is one of the most important consequences to be considered when planning new lines. Dynamic performance evaluation of tramway tracks is required to validate or modify the existing means that reduce vibrations. This paper presents experimental and theoretical investigations of vibrations caused by passing tramways in Nantes, France. A method is proposed to predict ground-borne vibrations, so as to estimate a trouble gauge concerning, for example, the impact of a future tramway line. This method is applied and validated in comparison with in situ measurement data obtained previously.Numerous studies have been carried out on vibrations induced by surface railways, for example, Lefeuve-Mesgouez et al. [1], Picoux [2] and Sheng et al. [3]. In the case of a tramway line, a two-dimensional model can be used to predict the behaviour of the propagation analysis of the corresponding vibrations, considering a thin layer model for the soil and using exact dynamic stiffness matrices [4,5], expressed in the frequency-wave number domain for the layered ground and the half-space [6]. Note that other models can be applied to predict vibration propagation, such as boundary element formulations [7].In this paper, soil is characterized by measurements using the spectral analysis of surface waves, often called the SASW method. Here the usual two-station approach is used [8]. The objective is to accurately define shear moduli and layer thicknesses. Then the general Barkan relation [9] is applied to obtain the dispersion curve and the damping ratios. Soil characterisation needs further improvements using a complete inversion method such as Occam's algorithm [10]. Nonetheless this first approach, often called "equivalent depth approach" already gives sufficient soil profile information to model waves propagation.Numerical methods, such as the wavenumber matrix approach, can be used for the prediction of the soil response to a hammer impact, i.e. to obtain the transfer functions. An alternative solution is proposed: the method is based on the assumption that for each frequency, the vertical measured shear wave velocity corresponds to a homogeneous half-space [9]. The vibratory response is obtained by multiplying the load spectrum by the transfer function in order to obtain the whole contribution of tramway passage for each measurement point. Results are given in the time domain and compared with in situ measurements.
Abstract
International audience; Tramway traffic may produce vibrations propagating in soil, which implies vibration annoyance for people living or working in neighbouring buildings. [...]
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Population exposure to urban highway traffic emissions
T. Fontes, N. Barros, L. Cunha, C. Brás

Collection of open conferences in research transport (2005). Vol. 2005, 66

Abstract
In this paper is presented firstly the traffic and emission characterization of Via de Cintura Interna (VCI), an urban highway at Oporto city, Portugal, with more than 4 000 vehicles/hour during rush hours. Emission estimates were carried through on the basis of emission factors to road transport published in the Atmospheric Emission Inventory Guidebook. A weighed emission factor has been calculated for nitrogen oxides (NOx) and vehicle class, according to the Portuguese fleet composition (vehicles age, type of engine and average speed). Furthermore, during a three-week period, an outdoor nitrogen dioxide (NO2) monitoring campaign was carried out in a domain around the VCI (100 m for each side), in particular near residential buildings. The results demonstrate that higher NO2 concentrations are seen in the sub-domain with higher circulation of heavy-duty vehicles and where buildings are adjacent to VCI hindering pollutant dispersion. Meteorological conditions, such as wind intensity and direction, temperature and solar radiation were monitorized too. The NO2 concentrations obtained by the monitoring campaign have been used to create scenarios of population exposure to NO2, having taken into account the time-activity patterns of residents. It was verified that higher exposures occur when the population lives in Boavista, in contrast with the favourable scenario that corresponds to life in Prelada and those working in Espinho city. The work and results presented in this paper are a part of the methodology used in the scope of the ImpactAir Project. This project, started in 2003 in Oporto city, has the main objective of evaluating the impact of urban highway (VCI) traffic emissions on air quality and the health of the local population.
Abstract
In this paper is presented firstly the traffic and emission characterization of Via de Cintura Interna (VCI), an urban highway at Oporto city, Portugal, with more than 4 000 [...]
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Off-line Flow Allocation for Traffic Engineering in MPLS Networks
S. Lahoud, G. Texier, L. Toutain

Collection of open conferences in research transport (2005). Vol. 2005, 65

Abstract
International audience; In this paper, we introduce a novel framework for the off-line flow allocation problem for traffic engineering in MPLS networks. We use a multi-stage optimization that considers minimizing successively congestion, resource consumption and operational costs. The framework is based on linear programming and presents an efficient solution for the problem both in terms of computational complexity and approximation guarantees. Preliminary simulation results prove that we can easily tune congestion and resource consumption while keeping low operational costs, expressed in the number of Label Switched Paths (LSPs) in use. Moreover, the flow allocation solution is obtained in a polynomial time and results can be further extended to larger topologies with a big number of demands.
Abstract
International audience; In this paper, we introduce a novel framework for the off-line flow allocation problem for traffic engineering in MPLS networks. We use a multi-stage [...]
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Methodology for evaluating and regression testing a conflict probe
M. Paglione, R. Oaks, H. Ryan

Collection of open conferences in research transport (2005). Vol. 2005, 64

Abstract
conflict probe is an air traffic management decision support tool that predicts aircraft-to-aircraft and aircraft-to-airspace conflicts. In order to achieve the confidence of the air traffic controllers who are provided this tool, a conflict probe must accurately predict these events. To ensure their continued confidence, the accuracy should not only be assessed in the laboratory before the probe is deployed but continue to be reassessed as the system undergoes upgrades and software changes. Furthermore, it is desirable to use recorded air traffic data to test these tools in order to preserve real-world errors that affect their performance. This paper utilizes a proven approach that modifies surveillance radar track data in time to create traffic scenarios containing conflicts with characteristic properties similar to those encountered in actual air traffic operations. It is these time shifted traffic scenarios that are used to evaluate the conflict probe. This paper describes the detailed process of evaluating the missed and false conflict predictions, the calculation of the corresponding error probabilities, and a regression testing methodology to examine two runs of the conflict probe to determine if the conflict prediction accuracy has improved or degraded over time. A detailed flight example is presented which illustrates the specific processing involved in conflict accuracy analysis. Next using a scenario of many flights, a methodology utilizing categorical data analysis techniques is applied to determine if a new version of the conflict probe's software significantly improved or degraded in conflict prediction accuracy.
Abstract
conflict probe is an air traffic management decision support tool that predicts aircraft-to-aircraft and aircraft-to-airspace conflicts. In order to achieve the confidence [...]
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Night-Vision Display Unlit during Uneventful Periods May Improve Traffic Safety
T. Alm, K. Ohlsson, R. Kovordanyi

Collection of open conferences in research transport (2006). Vol. 2006, 68

Abstract
It is always uncertain if a new assistance system will enhance traffic safety or not: empirical studies indicate that driving style may deteriorate when the driver experiences the increased safety margin created by an advanced driver assistance system. To minimize this negative effect on driving style, we redesigned a night vision system so that it appeared differently to the driver: we let the system's head-up display be turned off during operation, to be lit up only when the system detected an obstacle (e.g., a pedestrian or animal) on the road ahead. This presentation style was compared in a simulator study to the traditional solution of constantly lit-up display. The results indicate that drivers reacted more reliably (showed less variance in reaction times) using the new system, which implies that the lighting up of the IR-display constituted an effective warning. Also, drivers to a greater extent drove at normal (slower) speeds when using the re-designed system. More generally, systems offering discontinuous support (i.e. only in critical situations) may have less of a negative effect on driving style, as their presence is not felt as vividly by the driver.
Abstract
It is always uncertain if a new assistance system will enhance traffic safety or not: empirical studies indicate that driving style may deteriorate when the driver experiences [...]
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PE-RT: A New Class of Polyethylene for Industrial Pipes
D. Schramm

Collection of open conferences in research transport (2006). Vol. 2006, 67

Abstract
The development of a new family of PE materials with significantly improved processability and long term strength at high temperatures is discussed. These polymers form the basis for a new ISO class of polyethylene materials: PE-RT (Polyethylene of Raised Temperature resistance) for hot and cold water as well as industrial pipe applications. These materials have a unique molecular structure and crystalline microstructure, which provides excellent Long Term Hydrostatic Strength at high temperature without crosslinking the material. PE-RT type materials are successfully used in domestic hot and cold water piping systems for most applications. The easy processing and outstanding material properties made these resins also attractive for use in many industrial applications, where larger dimensions are required and regular Polyethylene cannot be used or has temperature limitations. They also compete against high end engineering plastics, offering significant cost savings. These materials provide significant process advantages to the converters, allowing high line speed pipe production and providing excellent flexibility and ease of installation for the application. A recently developed PE-RT type material offers still higher long-term strength at high temperature and further improved processability. This combination makes this resin particularly suitable for high temperature applications. An example of the latter is in larger diameter cooling water pipes in power plants. Pipes based on these materials can be connected via heat welding or by the use of mechanical fittings. Furthermore this material can be used in industrial applications, were traditional Polyethylene is limited by the temperature resistance and metallic materials suffer from corrosion. The excellent weldability of these materials provides various opportunities to connect also larger dimensions in industrial applications. Another example of this is the use in multi-layer structured oil pipelines on-shore and off-shore. This paper presents the material science and product design concepts that govern the high long-term hydrostatic strength at high temperatures. By controlling the molecular structure, the melt rheology and solid state properties can be influenced. This results in a unique balance of processability and hydrostatic strength. Further discussed are the product features and benefits of PE-RT materials. The paper shows examples of the application range for this type of products, using applications in the domestic pipes market as a reference study.
Abstract
The development of a new family of PE materials with significantly improved processability and long term strength at high temperatures is discussed. These polymers form the [...]
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Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels
C. McCowan, J. Merritt, J. McColskey, G. Kohn, P. Darcis, A. Bussiba, R. Smith, R. Fields

Collection of open conferences in research transport (2006). Vol. 2006, 65

Abstract
Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large degree of stable-tearing crack extension during the fracture process. This type of steady-state fracture resistance takes place when the CTOA in a material reaches a critical value, as typically occurs in low-constraint configurations. Our current research has applied the CTOA concept as an alternative or an addition to the Charpy V-notch and the drop weight tear test (DWTT) fracture energy in pipeline characterization. A test technique for direct measurement of CTOA was developed, using a modified double cantilever beam (MDCB) specimen. A digital camera and image analysis software are used to record the progression of the crack tip and to estimate CTOA using the crack edges adjacent to the crack tip. A steady-state CTOA has been successfully measured on five different strength grades of gas pipeline steel (four low strength grades and one high strength grade: X100). In addition, two-dimensional finite element models (2D FEMs) are used to demonstrate the sequence of the fracture process and the deformation mechanisms involved. The CTOA measurements and models are correlated and agree well.Copyright © 2006 by ASME
Abstract
Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure [...]
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Balancing System Level Pipelines with Stage Voltage Scaling
S. Parameswaran, H. Guo

Collection of open conferences in research transport (2005). Vol. 2005, 62

Abstract
This paper presents an approach to dynamically balance the pipeline by scaling the stage supply voltages. Simulation results show that by such an approach about 50% improvement in throughput and response time, and 11% improvement in power consumption can be achieved with limited memory overhead.
Abstract
This paper presents an approach to dynamically balance the pipeline by scaling the stage supply voltages. Simulation results show that by such an approach about 50% improvement [...]
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Traffic engineering in multihomed sites
A. García-Martínez, A. Azcorra, M. Bagnulo, C. Bernardos, I. Martinez

Collection of open conferences in research transport (2005). Vol. 2005, 61

Abstract
It is expected that IPv6 multihomed sites will obtain as many global prefixes as direct providers they have, so traffic engineering techniques currently used in IPv4 multihomed sites is no longer suitable. However, traffic engineering is required for several reasons, and in particular, for being able to properly support multimedia communications. In this paper we present a framework for traffic engineering in IPv6 multihomed sites with multiple global prefixes. Within this framework, we have included several tools such as DNS record manipulation and proper configuration of the policy table defined in RFC 3484. To provide automation in the management of traffic engineering, we analyzed the usage of two mechanisms to configure the policy table. This work has been partly supported by the European Union under the E-Next Project FP6-506869 and by the OPTINET6 project TIC-2003-09042-C03-01. Publicado
Abstract
It is expected that IPv6 multihomed sites will obtain as many global prefixes as direct providers they have, so traffic engineering techniques currently used in IPv4 multihomed [...]
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A New Approach to Risk Based Pipeline Integrity Management
S. Turner, R. Palmer-Jones, P. Hopkins

Collection of open conferences in research transport (2006). Vol. 2006, 60

Abstract
The use of risk based integrity management systems for pipelines is increasing in popularity, and now changes in legislation in the USA require operators to use risk assessment in high consequence areas. The methodologies used range from point scoring qualitative schemes to detailed quantified systems requiring structural reliability analysis, release modelling and post incident behavioural modelling. In the UK a risk based approach to pipeline integrity management has been included in legislation since 1996, and is widely used. Experience with implementing systems and applying them to onshore and offshore pipeline systems has led to the following conclusions: • Point scoring systems cannot replace expert knowledge. • Point scoring systems always need to be modified to suit a particular system and need updating as parameters change. • Detailed automated systems generate a huge number of sections and range of risks. this can be confusing and cannot easily be accounted for in inspection planning. • A clear link between risks and inspection or monitoring is needed. • Simplicity and flexibility are critical. This paper describes a radical new approach to using risk assessment for pipeline integrity management. This new approach focuses on identifying whether hazards are time dependant (e.g. corrosion) or random (e.g. third party damage), and then either estimating a time to failure or a probability of occurrence. These estimates can be based on experience, history, or specific detailed studies. The effect of inspection and monitoring is also considered. This methodology allows the user to manage the risks associated with their pipeline in a way that is flexible, rational, consistent, and can be readily understood by others. It also allows the reasons for decisions regarding inspections to be recorded, and new users to quickly learn the key safety issues for the pipeline.Copyright © 2006 by ASME
Abstract
The use of risk based integrity management systems for pipelines is increasing in popularity, and now changes in legislation in the USA require operators to use risk assessment [...]
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Ground vehicle guidance along collision-free trajectories using elastic bands
T. Brandt, T. Sattel

Collection of open conferences in research transport (2005). Vol. 2005, 60

Abstract
Latest developments in automotive sensor technology promise an unbroken innovation thrust for driver assistance systems. Accordingly, future vehicles might be able to navigate autonomously. For autonomous vehicles collision avoidance systems (CAS) are essential. Key elements of CAS are automatic path planning, path following and model based estimation of the driving conditions of a CAS-equipped car. For this purpose, a path planning technique using modified elastic bands is presented. Furthermore, a possible overall CAS-structure including path following control and driving condition estimation is discussed. Finally, simulation results for an evasion maneuver are given.
Abstract
Latest developments in automotive sensor technology promise an unbroken innovation thrust for driver assistance systems. Accordingly, future vehicles might be able to navigate [...]
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Probabilistic Assessment of a 70-Year Old Pipeline Subject to Seismic Deformation
B. Thacker, J. Hart, R. Warke

Collection of open conferences in research transport (2006). Vol. 2006, 59

Abstract
This paper presents an assessment case study on several segments of buried natural gas pipeline constructed in 1936 with ‘bell-bell-chill ring’ (BBCR) style girth weld joints, and currently operating in a seismically active region of North America. Seismic vulnerability was evaluated in terms of girth weld fracture and plastic collapse probabilities for specified hazards of varying severity and likelihood. Monte Carlo simulations performed in NESSUS® provided failure probability estimates from distributed inputs based on PIPLIN deformation analyses, nondestructive and destructive flaw sizing, residual stress measurements, weld metal tensile and CTOD tests, and limit state functions based on published stress intensity and collapse solutions.Copyright © 2006 by ASME
Abstract
This paper presents an assessment case study on several segments of buried natural gas pipeline constructed in 1936 with ‘bell-bell-chill ring’ (BBCR) style girth weld [...]
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State of the Art Assessment of Composite Systems Used to Repair Transmission Pipelines
B. Francini, C. Alexander

Collection of open conferences in research transport (2006). Vol. 2006, 57

Abstract
For the past decade there has been relatively wide acceptance in using composite materials to repair damaged gas and liquid transmission pipelines. There have been numerous independent research programs performed by pipeline companies, research organizations, and manufacturers that have contributed to the acceptance of composites as a legitimate repair material. Additionally, insights have been gained by both pipeline operators and composite repair manufacturers during field installations. ASME has also responded by adding sections to both the ASME B31.4 and B31.8 pipeline codes, as well as currently developing a repair standard for non-metallic composite repair systems by the Post Construction Committee. Stress Engineering Services, Inc. and Kiefner & Associates, Inc. have been integrally involved in assessing the repair of pipeline systems, with the former having been involved in performing full-scale testing and analysis on most of the major U.S.-based composite repair systems. The purpose of this paper is to provide for the pipeline industry a third-party evaluation of composite repair systems and information that is needed to properly evaluate how composite materials should be used to repair high pressure pipelines. The contents of the paper will include discussions on what critical elements should be evaluated for each composite system, items of caution and concern, and the importance of evaluation to ensure safe long-term performance.Copyright © 2006 by ASME
Abstract
For the past decade there has been relatively wide acceptance in using composite materials to repair damaged gas and liquid transmission pipelines. There have been numerous [...]
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Human factors issues in the collocation of URET, TMA, and CPDLC
P. Rocco, P. Sollenberger

Collection of open conferences in research transport (2005). Vol. 2005, 59

Abstract
The Federal Aviation Administration (FAA) Free Flight Program individually deployed the user request evaluation tool (URET), traffic management advisor (TMA), and controller-pilot data link communications (CPDLC) to a limited number of air route traffic control centers (ARTCCs). Before deployment expands nationwide, it was important to identify any potential human factors issues that may arise due to the collocation of these tools at the controller's workstation. In this paper, we present the results of a high fidelity human-in-the-loop simulation we conducted to evaluate the impact of URET, TMA, and CPDLC collocation on air traffic controllers. We examined collocation issues with a "stovepipe" independent configuration where none of the tools were integrated or directly communicated with each other. Twelve certified professional controllers participated in the simulation working in two-person teams consisting of a radar (R-side) and data (D-side) controller. The most important collocation issue identified was that controllers had difficulty accessing important information on the D-side display when URET and CPDLC were both operational (i.e., display clutter). Although neither tool alone caused display clutter, both tools in combination made it difficult for D-side controllers to find the information they needed quickly. This was especially true for accessing CPDLC windows, which became covered when controllers used URET. Good human factors design principles prescribe that users must have immediate access to important information and that critical information should never be covered. A "stovepipe" independent deployment of these tools will result in impaired access to timely information. The results of this study indicated that better efforts should be made to integrate the information from URET, TMA, and CPDLC on the D-side monitor prior to deployment of all three tools at the controller's workstation.
Abstract
The Federal Aviation Administration (FAA) Free Flight Program individually deployed the user request evaluation tool (URET), traffic management advisor (TMA), and controller-pilot [...]
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Inside the queue: hypercongestion and road pricing in a continuous time - continuous place model of traffic congestion
E. Verhoef

Collection of open conferences in research transport (2005). Vol. 2005, 58

Abstract
This paper develops a continuous time - continuous place model of road traffic congestion, based on car-following theory. The model fully integrates two archetype representations of traffic congestion technology, namely "flow congestion", originating in the works of Pigou, and "vertical queuing" models, pioneered by Vickrey. Because a closed-form analytical solution of the formal model does not exist, its behaviour is explored in a numerical exercise. In a setting with endogenous departure time choice and with a bottleneck halfway the route, it is shown that "hypercongestion" can arise as a dynamic - transitional and local - equilibrium phenomenon. Also dynamic toll schedules are explored. It is found that a toll rule based on an intuitive dynamic and space-varying generalization of the standard Pigouvian tax rule can hardly be improved upon. A naïve application of a toll schedule based on Vickrey´s bottleneck model, in contrast, performs much worse and actually even reduces welfare.
Abstract
This paper develops a continuous time - continuous place model of road traffic congestion, based on car-following theory. The model fully integrates two archetype representations [...]
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“Digital Pigging” as a Basis for Improved Pipeline Structural Integrity Evaluations
J. Hart, N. Zulfiqar, G. Swank, D. Moore

Collection of open conferences in research transport (2006). Vol. 2006, 54

Abstract
This paper describes the application of “digital pigging” procedures for converting field measurements of pipeline geometry (e.g., top of pipe survey profiles), results from geometry pig surveys, or analytically generated pipeline centerline profiles into corresponding profiles of pipeline curvature and bending strain. Application of digital pigging procedures to pipeline elevation and/or inclination profiles developed from accelerometer based geometry pigs provides a basis for performing the additional calculations required to develop bending strain profiles which may not be a part of the geometry survey deliverable but are required for pipeline structural integrity evaluations. This paper presents examples of digital pig runs over analytical pipe centerline profiles to illustrate the important effects of feature length, pig length and curvature gage length. Comparisons of the results from digital pig runs over actual geometry pig data profiles and digital pig runs over the corresponding known analytical profiles will illustrate how basic pattern recognition concepts can be used as a basis for improved synthesis of real pig data signatures. This paper also presents examples of digital pigging calculations performed on geometry pig survey data that show how low-pass filtering can be used to reduce the effects of noise in the survey data as well as the influence of curvature gage length on the computed curvature/bending strain profiles.Copyright © 2006 by ASME
Abstract
This paper describes the application of “digital pigging” procedures for converting field measurements of pipeline geometry (e.g., top of pipe survey profiles), results [...]
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Combining Sequencing Tool and Spacing Instructions to Enhance the Management of Arrival Flows of Aircraft
B. Favennec, K. Zeghal, F. Vergne, L. Boursier, L. Rognin, E. Hoffman

Collection of open conferences in research transport (2005). Vol. 2005, 56

Abstract
This paper reports on an experiment conducted with air traffic controllers to investigate the joint use of a sequencing tool and spacing instructions to enhance the management of arrival flows. The experiment simulated two en-route and one approach sectors (total of seven positions). It was shown that sequencing tool and spacing instructions can be jointly used in en-route and in the terminal area, with high benefits particularly in the terminal area. Main benefits are: a positive impact on controller activity (earlier flow integration and relief from late vectoring) and on control effectiveness (more regular inter-aircraft spacing on final approach, a slight increase of throughput and straighter trajectories with no dispersion below 4000ft).
Abstract
This paper reports on an experiment conducted with air traffic controllers to investigate the joint use of a sequencing tool and spacing instructions to enhance the management [...]
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Adaptive importance sampling for probabilistic validation of advanced driver assistance systems
O. Gietelink, B. Schutter, M. Verhaegen

Collection of open conferences in research transport (2006). Vol. 2006, 52

Abstract
We present an approach for validation of advanced driver assistance systems, based on randomized algorithms. The new method consists of an iterative randomized simulation using adaptive importance sampling. The randomized algorithm is more efficient than conventional simulation techniques. The importance sampling pdf is estimated by a kernel density estimate, based on the results from the previous iteration. The concept is illustrated with a simple adaptive cruise control problem.
Abstract
We present an approach for validation of advanced driver assistance systems, based on randomized algorithms. The new method consists of an iterative randomized simulation [...]
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Optimal Control Based Modeling of Vehicle Driver Properties
T. Butz, O. Stryk

Collection of open conferences in research transport (2005). Vol. 2005, 54

Abstract
In this paper, we present a two-level driver model for the use in real-time vehicle dynamics applications. On the anticipation level of this model, nominal trajectories for the path and the speed profile of the vehicle along a given course are determined by reducing the driving task to a parametric optimal control problem and using an efficient direct collocation method for its solution. Typical optimality criteria and control-state constraints serve to depict driving properties of different driver types. On the stabilization level, a nonlinear position controller guides the full vehicle dynamics model along the prescribed trajectories in real-time. This synthetic driver model allows easy implementation of different driving strategies to simulate a wide range of driver types and vehicles. The expediency of the proposed model is shown by comparing simulation results with measured data from several drivers performing ISO double lane changes with a passenger car. INTRODUCTION Main tasks in the development of modern motor vehicles are the increase of driving safety and comfort as well as the relief of the driver by driver assistance systems. To guarantee reliability and robust design of the developed vehicle controllers, it is necessary to investigate the performance of the vehicle-controller system in major parts of the dynamic spectrum which is realized in practical driving situations. To meet the demands of all eligible drivers, handling studies must be carried out over a broad range of different driver types. Nowadays, software for the numerical simulation of the full car dynamics is indispensable for the development of vehicles and vehicle dynamics controllers. Besides virtual prototyping and conceptual design in the computer, vehicle dynamics simulation programs are employed for real-time applications in Hardware(HIL) und Software-in-the-Loop (SIL) environments. Realistic simulation results do not only require a comprehensive vehicle model and a detailed representation of the road conditions. For the investigation of the closed control loop of vehicle, driver and environment also a technical driver model is necessary which allows implementing driving maneuvers during normal operation and at the driving limits. In the following, we investigate an optimal control based model to depict the driver’s properties in vehicle guidance. Its application in real-time vehicle dynamics simulation is investigated and simulation results are compared to measurements from driving tests. FULL VEHICLE DYNAMICS SIMULATION For the computation of the full vehicle dynamics in real-time a simulation model is needed which realistically depicts the vehicle system behavior and requires little computational time. The vehicle model implemented in the vehicle dynamics program veDYNA [15] is a generic, fully parameterized multi-body system for the basic vehicle. The nonlinear elasto-kinematics of almost arbitrary axle types can be depicted either by kinematic look-up tables or by detailed geometric models, including the respective control arms, drag links, subframes and bushings. In addition, partial models are employed to account for intrinsic vehicle dynamics, such as of the drive train, the steering mechanism, and the tires (cf. Fig. 1). Figure 1: Multi-body model in veDYNA including steering system and geometrical axle model. Custom methods for treating multi-body systems use the descriptor form of the equations of motion and yield a system of differential-algebraic equations of index 3. The choice of suitable generalized coordinates in veDYNA, however, eliminates algebraic constraints and reduces the differential-algebraic system to ordinary differential equations. Due to their stiffness the numerical integration is performed with a semi-implicit Euler scheme which allows stable, real-time capable integration of the vehicle's equations of motion for step sizes up to several milliseconds [12]. For the representation of the vehicle environment the veDYNA Road model is used which allows depicting almost arbitrary road layouts with high accuracy [3, 16]. In this model, the horizontal course can be constructed synthetically according to a unit construction system or by specifying spatial road coordinates. The height profile allows segments with vanishing or constant slopes to be joined smoothly with arched pieces. For the road surface characteristic, geometric disturbances, such as potholes or rail tracks, may be depicted as well as different weather conditions and stochastic roughness. Figure 2: veDYNA Road layout for the Formula 1 course in Monza [3]. Besides openand closed-loop controls realistic driving maneuvers can be implemented with the veDYNA Driver [14, 16]. The versatile non-linear position controller which is described in the next section is able to guide the vehicle along arbitrary tracks and to handle the vehicle during demanding driving tasks. The driver controller shows to some extent natural human vehicle handling activities, but in a reproducible and adjustable way [8]. veDYNA allows the realistic simulation of the full vehicle dynamics in arbitrary driving situations. The program is employed among major car manufacturers and suppliers for rapid prototyping and parameter studies as well as for comfort and safety investigations on the PC. Applications in Hardwareand Software-in-the-Loop test benches include design, calibration and test of vehicle dynamics controllers, such as anti-lock braking and traction control systems, as well as reliability tests by endurance runs. OPTIMAL CONTROL BASED DRIVER MODEL According to Donges [4] human vehicular control can be separated into guidance and stabilization. Accordingly, a two-level driver model is suggested consisting of an anticipation level, where nominal trajectories for vehicle guidance are selected, and a stabilization level, where suitable control actions for adhering to the reference input variables are implemented. In the two-level driver model developed in the following, nominal trajectories for the path and the speed profile of the vehicle are determined by optimal control methods. This approach is motivated by the optimal control model of Baron, Kleinman and Levison [1] for the stabilization level. Accordingly, a “well-motivated, welltrained human operator behaves in a near-optimal manner subject to his inherent limitations and constraints, and his control task.” While common models for the driver anticipation level select the road center line and the maximum permissible vehicle speed as trivial reference variables, we formulate the driving task as a parametric optimal control problem. To depict the driver’s motivation, a combination of suitable optimality criteria, such as maximum traveled distance and minimum mean-square values of the vehicle’s deviation from the road center line and the lateral acceleration, is used. In this regard, the current work extends the driver model of Ehmann et al. [5, 17] for racing applications where time-optimal set variables are computed. The optimal control approach promises an easily parameterizable, synthetic driver model which is suitable to investigate the objective vehicle handling properties in the computer over a broad range of drivers, maneuvers, tracks and vehicles. On the stabilization level, a non-linear position control algorithm serves to guide the vehicle precisely along the prescribed trajectories for path and speed profile. Some controller parameters, such as preview, controller gain and steering delay, may be adjusted to represent human properties in vehicle guidance [8]. As compared to classic driver models from linear control theory, this approach provides vehicular control independent of the respective driving maneuver and offers a small number of meaningful driver parameters. For a detailed discussion of other driver controllers we refer to [2]. ANTICIPATION LEVEL The computation of nominal path and speed trajectories for vehicle guidance requires a vehicle dynamics model which can be treated with optimal control methods. Suitable for this application is the single track model [11] shown in Fig. 3. The latter is a planar vehicle model where front and rear wheels are condensed to one single wheel each and the center of gravity is situated on road height. Vertical dynamics, pitch and roll motions as well as displacements of the wheels relative to the vehicle body are neglected. Figure 3: Single track model [11]. y,r F x,r F β
Abstract
In this paper, we present a two-level driver model for the use in real-time vehicle dynamics applications. On the anticipation level of this model, nominal trajectories for [...]
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Advances in Feature Identification Using Tri-Axial MFL Sensor Technology
F. Sander, S. Miller

Collection of open conferences in research transport (2006). Vol. 2006, 49

Abstract
Pipeline operators have been using intelligent in-line inspection (ILI) tools as part of their pipeline integrity management systems for several decades now. A wide variety of ILI tools have been developed to serve a multitude of uses. Most notable is the detection, locating, and sizing of metal loss corrosion. Magnetic Flux Leakage Technology (MFL) was developed for that exact purpose, however over the years technology and innovation has vastly improved the capabilities of MFL tools. This paper contains a comparison of historical and current pipeline feature identification/classification capabilities for axial magnetizing MFL tools with Tri-Axial sensor technology. The pipeline features discussed include corrosion, mechanical defects, structural pipeline components, as well as the physical and magnetic parameters that affect accurate identification, location, and/or sizing. Some of these features have never been detected, identified, or reported in the past, and now constitute a significant portion of the training and testing procedure that occurs in the certification of a new MFL data analyst.Copyright © 2006 by ASME
Abstract
Pipeline operators have been using intelligent in-line inspection (ILI) tools as part of their pipeline integrity management systems for several decades now. A wide variety [...]
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Single-Event Upset Analysis and Protection in High Speed Circuits
A. Benso, P. Prinetto, S. Carlo, G. Natale, M. Hosseinabady, P. Lotfi-Kamran

Collection of open conferences in research transport (2006). Vol. 2006, 48

Abstract
The effect of Single-Event Transients (SETs) (at a combinational node of a design) on the system reliability is becoming a big concern for ICs manufactured using advanced technologies. An SET at a node of combinational part may cause a transient pulse at the input of a flip-flop and consequently is latched in the flip-flop and generates a soft-error. When an SET conjoined with a transition at a node along a critical path of the combinational part of a design, a transient delay fault may occur at the input of a flip-flop. On the other hand, increasing pipeline depth and using low power techniques such as multi-level power supply, and multi-threshold transistor convert almost all paths in a circuit to critical ones. Thus, studying the behavior of the SET in these kinds of circuits needs special attention. This paper studies the dynamic behavior of a circuit with massive critical paths in the presence of an SET. We also propose a novel flip-flop architecture to mitigate the effects of such SETs in combinational circuits. Furthermore, the proposed architecture can tolerant a Single Event Upset (SEU) caused by particle strike on the internal nodes of a flip-flop.
Abstract
The effect of Single-Event Transients (SETs) (at a combinational node of a design) on the system reliability is becoming a big concern for ICs manufactured using advanced [...]
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Overview of Air Traffic Control using an SIMD COTS system
J. Kidman, J. Baker, W. Meilander, S. Reddaway

Collection of open conferences in research transport (2005). Vol. 2005, 52

Abstract
traffic control is an important application with demanding real-time database processing requirements. Systems that have been implemented using current approaches have typically been expensive, late, over-budget and have not performed up to specification. In part this is because, in attempting to meet the real-time requirements, developers have been driven to use complex algorithms and software for what are inherently relatively simple requirements. Our analysis indicates that the use of modern SIMD COTS systems enables guaranteed real-time performance to be achieved with simpler algorithms on modest amounts of hardware. This paper covers the system, the approach to the application and some of the solution details.
Abstract
traffic control is an important application with demanding real-time database processing requirements. Systems that have been implemented using current approaches have typically [...]
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Simulating the National Airspace System
W. Weiss, E. Lacher

Collection of open conferences in research transport (2005). Vol. 2005, 51

Abstract
This paper describes an event-step simulation model being developed for the FAA that can be used to evaluate how a change in one component of the airspace system affects the flow of air traffic in the rest of the system. The primary measure of system performance in the model is delay. The model design, sample model applications, and future model enhancements are discussed.
Abstract
This paper describes an event-step simulation model being developed for the FAA that can be used to evaluate how a change in one component of the airspace system affects the [...]
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Airspace congestion smoothing by multi-objective genetic algorithm
D. Daniel, P. Stephane, S. Oussedik

Collection of open conferences in research transport (2005). Vol. 2005, 50

Abstract
International audience; Air traffic control systems become more and more congested due to the increase of demand. One way to reduce this congestion is to modify the flight plans (slot of departure and route of aircraft) in order to adapt the demand to the available capacity. This paper addresses the general time-route assignment problem which can be stated as follows: one has to find an optimal time of departure and an optimal route for all the aircraft involved in the considered airspace, in order to minimize the associated congestion and the induced delay. This problem is a multi-objective NP_Hard problem. We perform our research on the application of multi-objective stochastic methods on real traffic data without using the flow network concept, but by simulating the flight of each aircraft. The first results show that our approach is able to reduce congestion of the French airspace by a factor 2.
Abstract
International audience; Air traffic control systems become more and more congested due to the increase of demand. One way to reduce this congestion is to modify the flight [...]
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A 10-Bit Algorithmic A/D Converter for Cytosensor Application
T. Rengachari, U. Moon, V. Sharma, G. Temes

Collection of open conferences in research transport (2005). Vol. 2005, 49

Abstract
novel 10-bit algorithmic A/D converter for cytosensor applications is described in this paper. The converter is capable of a conversion rate of 1.5-bits/phase. It has advantages compared with conventional architectures with respect to nonideal effects.
Abstract
novel 10-bit algorithmic A/D converter for cytosensor applications is described in this paper. The converter is capable of a conversion rate of 1.5-bits/phase. It has advantages [...]
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Systematic Figure of Merit Computation for the Design of Pipeline ADC
L. Barrandon, S. Crand, D. Houzet

Collection of open conferences in research transport (2005). Vol. 2005, 48

Abstract
The emerging concept of SoC-AMS leads to research new top-down methodologies to aid systems designers in sizing analog and mixed devices. This work applies this idea to the high-level optimization of pipeline ADC. Considering a given technology, it consists in comparing different configurations according to their imperfections and their architectures without FFT computation or time-consuming simulations. The final selection is based on a figure of merit. Comment: Submitted on behalf of EDAA (http://www.edaa.com/)
Abstract
The emerging concept of SoC-AMS leads to research new top-down methodologies to aid systems designers in sizing analog and mixed devices. This work applies this idea to the [...]
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Applying Statistical Control Techniques to Air Traffic Simulations
K. Benson, D. Goldsman, A. Pritchett

Collection of open conferences in research transport (2005). Vol. 2005, 46

Abstract
While the literature contains several adaptive sampling techniques for statistical comparison of competing simulated system configurations and for embedded statistical computations during simulation run-time, these techniques are often difficult to apply to air traffic simulations because of the complexity of air traffic scenarios and because of the variety of model and data types needed to fully describe air traffic. Adaptive sampling techniques can be beneficial to the study of air traffic; for example, adaptive techniques can use ranking and selection methods to compare the relative worth of the competing configurations and calculate the number of observations required for rigorous statistical comparison, often dramatically reducing the run-time duration of simulations. In this paper, we will describe the implementation of such procedures in the Reconfigurable Flight Simulator for air traffic simulations. We also discuss implications for the coordination of simulation, analysis, and design activities.
Abstract
While the literature contains several adaptive sampling techniques for statistical comparison of competing simulated system configurations and for embedded statistical computations [...]
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Robust Tracking of Longitudinal Objects Lying on the Sea Floor with an AUV equipped of a Scanning Sonar
C. Barat, M. Rendas

Collection of open conferences in research transport (2005). Vol. 2005, 45

Abstract
The paper considers the problem of using an autonomous underwater platform equipped with a scanning profiler sonar to track elongated objects lying on the sea floor, e.g., pipelines. The algorithm presented assumes the existence of features that enable the discrimination between sonar profiles received from the tracked object and those received from the background sea bottom. The algorithm does not require explicit classification of the profiles received (as coming from the tracked object or from the sea bottom), and does not rely on reconstruction of the geometry of the surface of the tracked object (allowing tracking of proud or partially buried objects). Simulation results illustrate the performance of the algorithm presented, as well as the effect of departures from the assumed geometric and reflectivity characteristics of the actual tracking configuration. Results of processing of real sonar profiles obtained at sea with a man-made object of cylindrical geometry are presented, demonstrating the appropriateness of the approach proposed
Abstract
The paper considers the problem of using an autonomous underwater platform equipped with a scanning profiler sonar to track elongated objects lying on the sea floor, e.g., [...]
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The microarchitecture of FPGA-based soft processors
P. Yiannacouras, J. Rose, J. Steffan

Collection of open conferences in research transport (2005). Vol. 2005, 44

Abstract
more embedded systems are built using FPGA platforms, there is an increasing need to support processors in FPGAs. One option is the soft processor, a programmable instruction processor implemented in the reconfigurable logic of the FPGA. Commercial soft processors have been widely deployed, and hence we are motivated to understand their microarchitecture. We must re-evaluate microarchiteture in the soft processor context because an FPGA platform is significantly different than an ASIC platform---for example, the relative speed of memory and logic is quite different in the two platforms, as is the area cost. In this paper we present an infrastructure for rapidly generating RTL models of soft processors, as well as a methodology for measuring their area, performance, and power. Using our automatically-generated soft processors we explore the microarchitecture trade-off space including: (i) hardware vs software multiplication support; (ii) shifter implementations; and (iii) pipeline depth, organization, and forwarding. For example, we find that a 3-stage pipeline has better wall-clock-time performance than deeper pipelines, despite lower clock frequency. We also compare our designs to Altera's NiosII commercial soft processor variations and find that our automatically generated designs span the design space while remaining very competitive.
Abstract
more embedded systems are built using FPGA platforms, there is an increasing need to support processors in FPGAs. One option is the soft processor, a programmable instruction [...]
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Achieving O(N) in simulating the billiards problem in discrete-event simulation
R. Rogers, G. Harless

Collection of open conferences in research transport (2005). Vol. 2005, 43

Abstract
The paper identifies underlying issues associate with simulating those classes of problems which require both arbitrary spatial and temporal precision and which must deal the with the complexities of a multitude of asynchronous pair-wise interactions occuring among a dynamic non-uniform distribution of numerous spatial components. The principal issue of interest discussed focuses on a proposed simulation modeling methodology which dynamically sectors the trajectory space based on the number of spatial objects occupying a portion of the trajectory space (i.e. object space density). That is, the trajectory space is divided into sectors of various sizes such that each sector contains no more than some specified number of spatial components. The authors demonstrate that with such a dynamic sectoring methodology a theoretical reduction in the total number of pair-wise comparisons required during each time advancement can be achieved. Additionally, the theoretical computational complexity associated with identifying spatial conflicts will be better than O(N/sup 2/) for a non-uniform distribution of N spatial objects.
Abstract
The paper identifies underlying issues associate with simulating those classes of problems which require both arbitrary spatial and temporal precision and which must deal [...]
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Tele-traffic engineering for enhanced UMTS multi-rate applications
F. Velez, E. Jose

Collection of open conferences in research transport (2005). Vol. 2005, 42

Abstract
The tele-traffic behaviour of enhanced UMTS (E-UMTS) is addressed in three different scenarios - business city centre (BCC), urban and roads. E-UMTS allows data rates up to 8-10 Mb/s to be achieved, far beyond the values for UMTS. In the absence of mobility, the difference between the supported users in each of the scenarios is not relevant. However, when mobility is considered, from BCC to the other two scenarios, the difference in the number of users is higher than 50% with 75 channels per link (per cell), and decreases around 40% with 100 channels. Within each of the scenarios, while in BCC the difference is small (17% reduction), in the other scenarios the reduction is higher than 50%. When the number of channels increases 33%, from 75 to 100 channels, the number of supported users increases ~100%, from 15.6 to 32.5 in the urban scenario and from 15 to 30 in the roads one, i.e., there is a statistical multiplexing gain.
Abstract
The tele-traffic behaviour of enhanced UMTS (E-UMTS) is addressed in three different scenarios - business city centre (BCC), urban and roads. E-UMTS allows data rates up to [...]
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Multilayer Traffic Engineering Performance in Overlay Networks
D. Colle, B. Puype, P. Demeester, M. Pickavet

Collection of open conferences in research transport (2006). Vol. 2006, 40

Abstract
Multilayer Traffic Engineering uses fast switching optical networks to modify or up/downgrade upper layer logical topologies according to changing traffic patterns. The multilayer overlay model limits information exchange between layers and thereby impacts overall performance.
Abstract
Multilayer Traffic Engineering uses fast switching optical networks to modify or up/downgrade upper layer logical topologies according to changing traffic patterns. The multilayer [...]
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A collaborative approach for human-centered driver assistance systems
J. Hollan, D. Forster, O. Achler, P. Fastrez, J. Haue, J. McCall, M. Trivedi, E. Boer

Collection of open conferences in research transport (2005). Vol. 2005, 40

Abstract
This paper describes an interdisciplinary research collaboration to design a human-centered driver assistance system. Driving behavior is captured using a novel intelligent vehicle test bed. The synchronized capture of driver behavior and driving context provides an empirical basis for the design and evaluation.
Abstract
This paper describes an interdisciplinary research collaboration to design a human-centered driver assistance system. Driving behavior is captured using a novel intelligent [...]
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Mixed conflict model for Air Traffic Control
T. Feydy, N. Barnier, P. Brisset, N. Durand

Collection of open conferences in research transport (2005). Vol. 2005, 39

Abstract
ce congestion is today the most critical issue European Air Traffic Management (ATM) has to face. Current real-time Air Traffic Control (ATC) is achieved by human controllers. One of their main tasks is to keep separation between aircraft, asking to the pilots to do basic avoidance manoeuvres. We propose here two mixed CSP models of this separation issue, combining discrete and continuous variables. An implementation of these models allows to produce optimal solutions for problems where numerous aircraft are conflicting.
Abstract
ce congestion is today the most critical issue European Air Traffic Management (ATM) has to face. Current real-time Air Traffic Control (ATC) is achieved by human controllers. [...]
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Analysis for instances' staying-time distribution in the workflow
S. Zhang, Y. Fan, S. Liu

Collection of open conferences in research transport (2005). Vol. 2005, 38

Abstract
Performance analysis can help us reduce requests' congestions in a workflow network, cut servers' cost or strike a best balance between them. Analysis for requests' remaining time at a workflow network plays an important role in the per-formance analysis for time-constrained workflow. Because requests' remaining time has complex relations with the arrival rate of users' service requests, the service rate of each server for each activity, servers' number and the structure of the workflow network, it is difficult to give a quantificational analysis for requests' remaining time. We develop a method to determine probability density function of requests' remaining time at a workflow network so that we will know the accurate proportion of requests can be executed without delay. An experiment illustrates our method can be effectively utilized in practice.
Abstract
Performance analysis can help us reduce requests' congestions in a workflow network, cut servers' cost or strike a best balance between them. Analysis for requests' remaining [...]
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Impact of Change Processes on Relationships Between Safety Culture and Organizational Climate Within Air Traffic Control
Å. Ek, M. Arvidsson, R. Akselsson, C. Johansson, B. Josefsson

Collection of open conferences in research transport (2006). Vol. 2006, 37
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Multi-Center Traffic Management Advisor: Operational Test Results
D. Rowe, T. Hoang, M. Nickelson, T. Farley, S. Landry, K. Levin, J. Welch

Collection of open conferences in research transport (2005). Vol. 2005, 37

Abstract
The Multi-Center Traffic Management Advisor (McTMA) is a research prototype system which seeks to bring time-based metering into the mainstream of air traffic control (ATC) operations. Time-based metering is an efficient alternative to traditional air traffic management techniques such as distance-based spacing (miles-in-trail spacing) and managed arrival reservoirs (airborne holding). While time-based metering has demonstrated significant benefit in terms of arrival throughput and arrival delay, its use to date has been limited to arrival operations at just nine airports nationally. Wide-scale adoption of time-based metering has been hampered, in part, by the limited scalability of metering automation. In order to realize the full spectrum of efficiency benefits possible with time-based metering, a much more modular, scalable time-based metering capability is required. With i
Abstract
The Multi-Center Traffic Management Advisor (McTMA) is a research prototype system which seeks to bring time-based metering into the mainstream of air traffic control (ATC) [...]
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Conflict Prevention and Separation Assurance in the Small Aircraft Transportation System
D. Williams, C. Muñoz, M. Consiglio, V. Carreño

Collection of open conferences in research transport (2005). Vol. 2005, 36

Abstract
multilayer approach to the prevention of conflicts due to the loss of aircraft -to -aircraft separation which relies on procedures and on -board automation was implemented as part of the SATS HVO Concept of Operations. The multilayer system gives pilots support and guidance during the execution of normal operations and advance warning for procedure deviations or off -nominal operations. This paper describes the major concept elements of this multilayer approach to separation assurance and conflict prevention and provides the rationale for its design. All the algorithms and functionality described in this paper have been implemented in an aircraft simulation in the NASA Langley Research Center’s Air Traffic Operation Lab and on the NASA Cirrus SR22 research aircraft.
Abstract
multilayer approach to the prevention of conflicts due to the loss of aircraft -to -aircraft separation which relies on procedures and on -board automation was implemented [...]
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A sliding mode control design for aircraft rendezvous at meter fix
E. Nationale, F. Mora-Camino, T. Miquel, A. Achaibou

Collection of open conferences in research transport (2005). Vol. 2005, 35

Abstract
International audience; The delegation to the flight crew of some tasks currently performed by air traffic controllers provides new perspectives to potentially increase air traffic control efficiency. More specifically, the task of establishing properly spaced landing sequences is very demanding in heavy traffic conditions for the air traffic controllers in charge of the terminal manoeuvring area. Automatic merging and station keeping operations could relieve air traffic controller of providing time consuming radar vectoring instructions. The objective of this communication is to provide technical insight into the airborne devices and algorithms which may be used onboard aircraft to automatically achieve a specified distance or delay with respect to another aircraft at a specified meter fix. A nonlinear control law based on sliding mode control is proposed to control the lateral motion of the trailing aircraft. The design is followed by two illustrative examples which show the effectiveness of the proposed approach.
Abstract
International audience; The delegation to the flight crew of some tasks currently performed by air traffic controllers provides new perspectives to potentially increase air [...]
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Real-time coordination of autonomous vehicles
M. Bouroche, B. Hughes, V. Cahill

Collection of open conferences in research transport (2006). Vol. 2006, 34

Abstract
utonomous vehicles seem to be a promising approach to both reducing traffic congestion and improving road safety. However, for such vehicles to coexist safely, they need to coordinate their behaviour to ensure that they do not collide with each other. This coordination is typically based on (wireless) communication between vehicles and needs to satisfy stringent real-time constraints. However, realtime message delivery cannot be guaranteed in dynamic wireless networks which means that existing coordination models that rely on continuous connectivity cannot be employed. In this paper, we present a novel coordination model for autonomous vehicles that does not require continuous real-time connectivity between participants in order to ensure that system safety constraints are not violated. This coordination model builds on a real-time communication model for wireless networks that provides feedback to entities about the state of communication. The coordination model uses this feedback to ensure that vehicles always satisfy safety constraints, by adapting their behaviour when communication is degraded. We show that this model can be used to coordinate vehicles crossing an unsignalised junction
Abstract
utonomous vehicles seem to be a promising approach to both reducing traffic congestion and improving road safety. However, for such vehicles to coexist safely, they need to [...]
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Cybercars : Past, Present and Future of the Technology
M. Parent, A. De La Fortelle

Collection of open conferences in research transport (2005). Vol. 2005, 34

Abstract
utomobile has become the dominant transport mode in the world in the last century. In order to meet a continuously growing demand for transport, one solution is to change the control approach for vehicle to full driving automation, which removes the driver from the control loop to improve efficiency and reduce accidents. Recent work shows that there are several realistic paths towards this deployment : driving assistance on passenger cars, automated commercial vehicles on dedicated infrastructures, and new forms of urban transport (car-sharing and cybercars). Cybercars have already been put into operation in Europe, and it seems that this approach could lead the way towards full automation on most urban, and later interurban infrastructures. The European project CyberCars has brought many improvements in the technology needed to operate cybercars over the last three years. A new, larger European project is now being prepared to carry this work further in order to meet more ambitious objectives in terms of safety and efficiency. This paper will present past and present technologies and will focus on the future developments.
Abstract
utomobile has become the dominant transport mode in the world in the last century. In order to meet a continuously growing demand for transport, one solution is to change [...]
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Tarrant Regional Water District's Risk Management Plan for Prestressed Concrete Cylinder Pipe
B. Mergalas, D. Marshall, M. Zarghamee, Y. Kleiner

Collection of open conferences in research transport (2005). Vol. 2005, 33

Abstract
The Tarrant Regional Water District (TRWD) operates two, 120 km long, large diameter prestressed concrete cylinder pipelines in north central Texas to daily supply water to over 1.5 million people. Both pipelines have suffered from failures due to corrosion, hydrogen embrittlement or inadequate thrust restraint, with about 800 pipe segments damaged. A model was developed to determine remaining strength of the damaged pipe. About 100 pipe segments, most of which have been replaced, were found to be damaged enough that they could fail and about 250 more were found to be damaged enough that further deterioration would put them at risk of failure. To prioritize their replacement, the District will use a fuzzy risk model. TRWD is attempting to balance the high cost of mitigating all damaged pipes with the potential cost of consequential damages due to a failure by modeling the risk. This paper will discuss the path TRWD is taking to further its model development of risk management of the pipeline.
Abstract
The Tarrant Regional Water District (TRWD) operates two, 120 km long, large diameter prestressed concrete cylinder pipelines in north central Texas to daily supply water to [...]
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Comparing traffic engineering objective functions
G. Leduc, F. Skivée, S. Balon

Collection of open conferences in research transport (2005). Vol. 2005, 32

Abstract
We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem as a linear program and solve it to optimality, thus finding for each objective function the best possible target of any heuristic TE algorithm. Our first results on the GEANT network suggest that they can give quite different results.
Abstract
We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective [...]
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Air and Ground Simulation of Terminal-Area Traffic Management with Airborne Spacing
P. Lee, T. Callantine, E. Palmer, J. Mercer, T. Prevot

Collection of open conferences in research transport (2005). Vol. 2005, 31

Abstract
Controller and pilot decision support tools for operations with airborne spacing in the terminal area were evaluated in a simulation conducted at NASA Ames Research Center as part of the NASA Advanced Air Transportation Technologies project Distributed Air Ground Traffic Management element. The results indicate that airborne spacing improves spacing accuracy and may help reduce go-arounds. Controller workload is acceptable and spacing clearances containing lead aircraft callsigns are clear. Expected operational benefits depend on traffic flow coordination and predictable spacing guidance and support tool behavior.
Abstract
Controller and pilot decision support tools for operations with airborne spacing in the terminal area were evaluated in a simulation conducted at NASA Ames Research Center [...]
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Accommodating ATC System Evolution through Advanced Training Techniques
R. Bolczak, J. Celio

Collection of open conferences in research transport (2005). Vol. 2005, 30

Abstract
The Federal Aviation Administration (FAA) expects air traffic volume and complexity to continue to increase, and with it the demand for air traffic control (ATC) services. The present controller training process and methods need to be enhanced to deal effectively with projected hiring increases, workforce changes, and operational changes anticipated in the future air transportation evolution. Advanced training techniques, such as scenario based instruction, voice recognition and synthesis and Intelligent Tutoring Systems (ITS) will reduce the time and costs required to attain Certified Professional Controller (CPC) status. Benefits such as increased flexibility in scheduling, more rapid response to facility staffing needs, and reduced stress on training resources such as instructors can be realized. The expected introduction of advanced ATC automation capabilities will affect the skills and knowledge mix of the controller workforce and may provide the opportunity for controller specialization that would result in increased efficiency while lowering overall costs. This paper summarizes the recent MITRE CAASD research into training methods, provides a high-level overview of the advanced ATC automation capabilities that could be introduced, presents recommendations for changes to the training process and its potential impact on training for both the current and future systems.
Abstract
The Federal Aviation Administration (FAA) expects air traffic volume and complexity to continue to increase, and with it the demand for air traffic control (ATC) services. [...]
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Predictability for real-time command and control
W. Meilander, J. Potter, J. Baker

Collection of open conferences in research transport (2005). Vol. 2005, 29

Abstract
This paper describes a new and different paradigm for real-time command and control that we show can provide a static, polynomial-time scheduling algorithm. Current efforts in real -time scheduling have been unable to predict system performance, and use a unpredictable "dynamic" scheduling algorithm. The Nation’s Air Traffic Control (ATC) System has been unable to satisfy performance requirements, and is extremely expensive. An editorial in "USA Today" (419-1999) cites expenditures in ATC at $41 billion. But, current multiprocessor technology cannot do the job. The FAA wisely required a “proof of concept” study before the (AAS) contract. But that study, after expending a billion dollars, was abandoned, and production moved forward. AAS was canceled in 1995 exactly in line with real-time scheduling theory predictions. Garey, Graham, and Johnson state: "For these scheduling problems, no efficient optimization algorithm has yet been found, and indeed, none is expected.”[9]. Stankovic et. al. state: "…complexity results show most real-time multiprocessing scheduling is NP -hard.” [6]. We offer a completely different approach, that has been shown to overcome the severe limitations of multiprocessi ng. Additionally, we show that real-time parallel-processing techniques can be statically scheduled to solve the set of tasks making up the ATC problem for a worst-case environment.
Abstract
This paper describes a new and different paradigm for real-time command and control that we show can provide a static, polynomial-time scheduling algorithm. Current efforts [...]
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Aviation communications emulation testbed
C. Sheehe, T. Mulkerin

Collection of open conferences in research transport (2005). Vol. 2005, 28

Abstract
viation related applications that rely upon datalink for information exchange are increasingly being developed and deployed. The increase in the quantity of applications and associated data communications expose problems and identify issues to resolve. NASA's Glenn Research Center is developing an aviation communications emulation testbed for studying the communications issues, which arise as datalink applications are employed within the National Airspace System (NAS). The testbed is evolving and currently provides the hardware and software needed to study the communications impact of air traffic control (ATC) and surveillance applications in a densely populated environment. The communications load associated with up to 160 aircraft transmitting and receiving ATC and surveillance data can be generated in realtime in a sequence similar to what would occur in the NAS. The ATC applications that can be studied are the aeronautical telecommunications network's (ATN) context management (CM) and controller pilot data link communications (CPDLC). The surveillance applications are automatic dependent surveillance - broadcast (ADS-B) and traffic information services - broadcast (TIS-B).
Abstract
viation related applications that rely upon datalink for information exchange are increasingly being developed and deployed. The increase in the quantity of applications and [...]
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Performance evaluation of QoS routing algorithms
K. Maalaoui, M. Tezeghdanti, J. Bonnin, A. Belghith

Collection of open conferences in research transport (2005). Vol. 2005, 27

Abstract
International audience; Summary form only given. New emergent distributed multimedia applications require end-to-end quality of service (QoS) guarantees and have stringent constraints on delay, jitter, cost, etc. Taking into account such needs in IP networks stands of utmost necessity. MPLS and traffic engineering provide indeed an adequate mean to establish constrained routes which satisfy application requirements especially in terms of bandwidth and delay. These routes are computed by running a QoS algorithm on the traffic engineering database maintained by an extended IGP routing protocol. In this paper, we first study and analyze three known QoS algorithms, namely SPF-TE, WSPF and DORA. This study is done through very detailed simulations using ONS, a simulator of the OSPF protocol, recently developed and integrated into the well known NS simulator. We show that while all these algorithms outperform clearly SPF, the algorithm usually used within OSPF, DORA algorithm stands slightly better than the two others. Then, we propose three different potential improvements of DORA and propose a new QoS algorithm termed WDORA that incorporates one these improvements. We show that WDORA outperforms DORA for different performance metrics.
Abstract
International audience; Summary form only given. New emergent distributed multimedia applications require end-to-end quality of service (QoS) guarantees and have stringent [...]
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Traffic characterization for traffic engineering purposes: analysis of Funet data
R. Susitaival, I. Juva, M. Peuhkuri, S. Aalto

Collection of open conferences in research transport (2005). Vol. 2005, 26

Abstract
For Internet traffic engineering purposes, it is important to characterize traffic volumes typically over 5-minute intervals. Based on measurements made in a local network at Lucent in winter 1999, Cao et al., (2000) proposed a moving IID Gaussian model for the characterization of 5-minute traffic volumes, with a power-law relationship between the mean and the variance. In this paper we analyze novel measurements gathered from a 2.5 Gbps link in the Finnish university network (Funet) in summer 2004. We investigate the validity of the moving IID Gaussian model and the proposed mean-variance relationship when the measurement interval is varying from 1 second to 5 minutes. As a result, we find that the Gaussian assumption is much more justified with current core link rates. The mean-variance relationship seems, indeed, to follow a power-law with exponent approximately equal to 1.3 in our data set. However, the IID assumption concerning the standardized residual is not verified, but we find a clear positive correlation between adjacent 5-minute volumes, and only slightly weaker negative correlation for traffic volumes with distance 20-30 minutes. In addition, we demonstrate that the same phenomenon is already prevailing in the Lucent data set.
Abstract
For Internet traffic engineering purposes, it is important to characterize traffic volumes typically over 5-minute intervals. Based on measurements made in a local network [...]
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Hazardous material transport accidents: analysis of the D.G.A.I.S. database
G. Spadoni, S. Bonvicini

Collection of open conferences in research transport (2005). Vol. 2005, 24

Abstract
In this paper results are presented and discussed about the analysis of the data of hazardous materials road transport accidents reported by the Canadian database D.G.A.I.S. (Dangerous Goods Accident Information System). The records of the database have been subdivided first of all on the basis of the transport phase to which they belong; then they have been classified by the accident typology and, for each type, by its primary cause. Subsequently accidents with hazmat release have been grouped considering the physical state of the spilled substance, in order to determine, basing on the leaked mass, the release categories and their occurrence probabilities. Finally the post-release event trees have been drawn and quantified for flammables. This work has allowed on one hand to determine the major causes of accidents and thus the actions to adopt for reducing the accident frequencies; on the other hand it has been possible to extract data for transport risk analysis, also suggesting useful improvements for bettering the quality of the information recorded by accident databases.
Abstract
In this paper results are presented and discussed about the analysis of the data of hazardous materials road transport accidents reported by the Canadian database D.G.A.I.S. [...]
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New Solution for Urban Traffic: Small-Type Monorail System
O. Seiichi, M. Hiraishi, A. Ito, K. Goda, Y. Sugita, T. Kuwabara

Collection of open conferences in research transport (2005). Vol. 2005, 23

Abstract
In Japan, the first urban straddle type monorail system, Tokyo Monorail, was put into operation in 1964. Since then, four more monorail systems have been constructed with the active participation of Hitachi in Kitakyushu, Osaka, Tama, and Okinawa. The straddle type monorail can be constructed using the space above public roads without disturbing everyday traffic. Monorail trains with rubber tires are environmentally friendly and produce little noise and vibration. The straddle type monorail has become an important part of the urban public transportation system, chiefly because of its many advantages over other transportation means including the subway. These advantages include (1) improved environment, (2) a shorter construction period, and (3) lower costs. Thus, the monorail system in Japan is an effective solution to environmental problems and traffic congestion in urban cities, which also stimulates local economy. The demand for urban monorail systems has recently begun to come from smaller local cities where the daily ridership is much lower than that in Tokyo, Osaka, Kitakyushu, and other major cities in Japan. To enhance the financial viability of monorail construction in smaller cities and to construct smaller monorails, the Japan Monorail Association (JMA) set up a research committee to investigate the development of a small monorail. This committee, mainly headed by Hitachi, carried out comprehensive research of the market demand for monorail systems and initiated the development of a compact monorail. Hitachi developed a number of new design elements including an articulated bogie to enable trains to negotiate sharp curves. We also worked to design a compact and light monorail that makes use of next-generation signal systems. These basic elements can also be used for other people-mover systems in amusement parks, airports, and business complexes.
Abstract
In Japan, the first urban straddle type monorail system, Tokyo Monorail, was put into operation in 1964. Since then, four more monorail systems have been constructed with [...]
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Differentiated traffic engineering for QoS provisioning
M. Shayman, V. Tabatabaee, B. Bhattacharjee, R. La

Collection of open conferences in research transport (2005). Vol. 2005, 22

Abstract
We introduce a new approach for QoS provisioning in packet networks based on the notion of differentiated traffic engineering (DTE). We consider a single AS network capable of source based multi-path routing. We do not require sophisticated queuing or per-class scheduling at individual routers; instead, if a link is used to forward QoS sensitive packets, we maintain its utilization below a threshold. As a consequence, DTE eliminates the need for per-flow (IntServ) or per-class (DiffServ) packet processing tasks such as traffic classification, queueing, shaping, policing and scheduling in the core and hence poses a lower burden on the network management unit. Conversely, DTE utilizes network bandwidth much more efficiently than simple over-provisioning. In this paper, we propose a complete architecture and an algorithmic structure for DTE. We show that our scheme can be formulated as a non-convex optimization problem, and we present an optimal solution framework based on simulated annealing. We present a simulation-based performance evaluation of DTE, and compare our scheme to existing (gradient projection) methods.
Abstract
We introduce a new approach for QoS provisioning in packet networks based on the notion of differentiated traffic engineering (DTE). We consider a single AS network capable [...]
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Air Traffic Management Simulation Data Visualization and Processing Tool
T. Callantine

Collection of open conferences in research transport (2005). Vol. 2005, 21

Abstract
Large-scale distributed simulations in which pilot participants fly simulators through multiple airspace sectors managed by controller participants create a rich operational environment for investigating new air traffic management concepts. This paper describes a Java™-based tool that aids in integrating, visualizing, and transforming data collected from large-scale human-in-the-loop air traffic management simulations. I. Introduction UTURE Air Traffic Management (ATM) concepts commonly leverage flight deck and ground-based automation and new interface tools to improve efficiency. To evaluate the feasibility and benefits of proposed concepts, researchers need ways to assess changes in practitioner roles and responsibilities, in addition to traditional system performance, human performance, and acceptability metrics. One way to investigate air-ground integration issues is to use large-scale simulations in which pilot participants fly simulators through multiple airspace sectors managed by controller participants, creating a rich ATM environment. This paper describes a Java™-based tool called DProc that aids in visualizing, integrating and transforming data collected from large-scale ATM simulations. DProc was implemented to process data from simulations in the Airspace Operations Laboratory (AOL) at NASA Ames Research Center. Controller stations, piloted and pseudo-piloted aircraft simulations—as well as simulation manager and ‘host computer’ components—all produce data describing particular aspects of an overall simulation. A given controller station, for example, logs actions performed by that air traffic controller subject, while the host computer provides a repository for aircraft state and trajectory information and logs descriptive data. Researchers may be interested in tracing event sequences, information flows, and operational contexts associated with certain outcomes of interest. This may entail identifying what other human subjects or automation agents are doing when one performs an action, and measuring relationships such as the time between various events or actions. Analysts can, of course, use traditional tools like spreadsheets to examine ATM simulation data and analyze interactions. However, the different types, formats, and sheer quantity of data can make this difficult. Moreover, data collected in a research environment with prototype automation tools may require integrity checking and other preprocessing steps prior to analysis. DProc addresses these issues by creating a database of merged simulation data from various sources. The DProc interface enables researchers to replay simulated traffic and visualize recorded events together with aircraft states. Visualization data may be color-coded according to traffic characteristics (e.g., aircraft weight class, equipage, engaged autoflight modes), or filtered to highlight events associated with a particular controller, aircraft, or class of aircraft. In addition to replaying data, DProc is also capable of producing plots of aircraft tracks or event locations. In addition to visualizations, DProc also produces batch output suitable for input to a spreadsheet or other analysis tool. As an example, the paper notes how DProc produces input files for data mining applications. Finally, the paper describes potential enhancements to DProc. For example, audio and video, as well as other subjective data collected during or after a simulation run might also be integrated and used to support analysis.
Abstract
Large-scale distributed simulations in which pilot participants fly simulators through multiple airspace sectors managed by controller participants create a rich operational [...]
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A BGP Attack Against Traffic Engineering
D. Nicol, X. Dimitropoulos, J. Kim, G. Riley, S. Ko

Collection of open conferences in research transport (2005). Vol. 2005, 19

Abstract
the Internet grows, traffic engineering has become a widely-used technique to control the flow of packets. For the inter-domain routing, traffic engineering relies on configurations of the border gateway protocol (BGP). While it is recognized that the misconfiguration of BGP can cause negative effects on the Internet, we consider attack methods that disable traffic engineering regardless of the correctness of configurations. We focus on the redirection of traffic as our attack objective, and present attack scenarios on some dominant sample network topologies to achieve this objective. We also evaluate and validate these attacks using two different discrete-event simulators, one that models BGP behavior on a network, and another that emulates it using direct-execution of working BGP code.
Abstract
the Internet grows, traffic engineering has become a widely-used technique to control the flow of packets. For the inter-domain routing, traffic engineering relies on configurations [...]
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LOGGING, ALERT & EMERGENCY SYSTEM FOR ROAD TRANSPORT VEHICLES - An Experimental eCall, Black-box and Driver Alerting System
J. Fernandez, V. Egido, M. Mata, F. Cantalapiedra, S. Bemposta

Collection of open conferences in research transport (2006). Vol. 2006, 23

Abstract
This paper describes the experimental platform developed at UEM, mounted on a conventional vehicle. It monitors most of the driver’s actions on the controls of the vehicle, logs the vehicle speed and position using a GPS, detects and recognizes vertical traffic signs, and records the last seconds of the trip with a panoramic video camera. If an accident occurs, the system calls emergency services (112 in Spain) sending vehicle position information (via SMS) and opening a voice channel Remove selected. SIN FINANCIACIÓN No data (2006) UEM
Abstract
This paper describes the experimental platform developed at UEM, mounted on a conventional vehicle. It monitors most of the driver’s actions on the controls of the vehicle, [...]
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A Neuro-Dynamic Based Conflict Resolution Scheme for Air Traffic Management
X. Papageorgiou, K. Kyriakopoulos

Collection of open conferences in research transport (2005). Vol. 2005, 17

Abstract
The aim of this paper is to study a numerical solution for the 2-D conflict resolution problem in air traffic management (ATM). This numerical solution is achieved using nonlinear programming and neural-networks. We use a set of optimal solutions obtained by nonlinear programming in order to train the neural network. We validated our methods with simulations and we compared the optimal and suboptimal solutions for the same scenario
Abstract
The aim of this paper is to study a numerical solution for the 2-D conflict resolution problem in air traffic management (ATM). This numerical solution is achieved using nonlinear [...]
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Co-Operative Air Traffic Management: Concept and Transition
T. Prevot, P. Lee, T. Callantine, J. Mercer, N. Smith, E. Palmer, V. Battiste

Collection of open conferences in research transport (2005). Vol. 2005, 16

Abstract
Co-Operative Air Traffic Management (CO-ATM) is a concept under exploration at NASA Ames Research Center for transformation of aircraft and air traffic management operations towards the Next Generation Air Transportation System (NGATS). A goal of the CO-ATM concept is to provide a scalable framework to significantly increase NAS capacity and efficiency while maintaining safety. A second goal of this concept is to provide airspace users with increased flexibility in managing their operations. The concept aims at achieving substantial capacity and efficiency benefits through improved information exchange and changes in roles and responsibilities. It builds on lessons learned from Distributed Air/Ground Traffic Management (DAG-TM) research, and addresses identified safety, coordination, automation and mixed equipage concerns. CO-ATM provides a transition path from the current system to the next generation with gradual shifts in roles and responsibilities and incentives for aircraft operators to equip. CO-ATM envisions sector controllers controlling conventional aircraft along predictable flight paths and area controllers coordinating strategic trajectory changes with flight crews of equipped aircraft in the same airspace via data link. Area controllers operate with extensive automation support for conflict detection and resolution and traffic flow management. Flight path changes are automatically shared as 4D trajectories between area and sector positions. Routine tasks like handoffs and transfer of communication are conducted by the automation. Equipped aircraft may be cleared to operate at different levels of autonomy. Tasks like aircraft-to-aircraft spacing may be delegated to the flight crews by the controller. Flight crews of equipped aircraft can coordinate preferred trajectories for traffic flow constraints with the area controller or operate at higher levels of autonomy, if desired and authorized. The paper reviews plans and concepts for the NGATS and relevant research findings from DAG-TM studies. It introduces the CO-ATM concept in detail and presents a possible transition path in line with ongoing research at NASA Ames, addressing the integration of trajectory based operations and Airborne Separation Assistance Systems (ASAS). This concept is currently in its definition and exploration phase and is in line with research funded in the NextNAS project of NASA's Airspace Systems Program.
Abstract
Co-Operative Air Traffic Management (CO-ATM) is a concept under exploration at NASA Ames Research Center for transformation of aircraft and air traffic management operations [...]
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Special Phased Array Applications for Pipeline Girth Weld Inspections
M. Moles, S. Labbe

Collection of open conferences in research transport (2006). Vol. 2006, 22

Abstract
Ultrasonic phased arrays present major improvements over conventional multiprobe ultrasonics for inspecting pipeline girth welds, both for onshore and for offshore use. Probe pans are lighter and smaller, permitting less cutback; scans are quicker due to the smaller probe pan; phased arrays are considerably more flexible for changes in pipe dimensions or weld profiles, and for different scan patterns. More important, some of the potential advantages of phased arrays are now becoming commercially available. These include: • Compensating for variations in seamless pipe wall thickness. • Wedge temperature compensation. • Improved focusing for thick and thin wall inspections. • Premium inspections for risers, tendons and other components. • Small diameter pipes. • Multiple displays. • Clad pipe. The paper describes the latest phased array UT results for special applications.Copyright © 2006 by ASME
Abstract
Ultrasonic phased arrays present major improvements over conventional multiprobe ultrasonics for inspecting pipeline girth welds, both for onshore and for offshore use. Probe [...]
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A Contribution to Branch Prediction Modeling in WCET Analysis
C. Burguière, C. Rochange

Collection of open conferences in research transport (2005). Vol. 2005, 15

Abstract
Submitted on behalf of EDAA (http://www.edaa.com/); International audience; The wider and wider use of high-performance processors as part of real-time systems makes it more and more difficult to guarantee that programs will respect their strict deadlines. While the computation of Worst-Case Execution Times relies on static analysis of the code, the challenge is to model with enough safety and accuracy the behaviour of intrisically dynamic components. In this paper, we focus on the dynamic branch predictor. Several models to bound the number of branch mispredictions have been previously published. Some of them exhibit a high complexity while other ones have shown that taking into account semantic information from the source code makes things more tractable. We extend this work to more general nested loop structures. We also give some simulation results that show that the way branch mispredictions are usually taken into account cannot be both safe and accurate in the case of high-performance pipelines. We propose a more realistic approach to be used as part of WCET computation.
Abstract
Submitted on behalf of EDAA (http://www.edaa.com/); International audience; The wider and wider use of high-performance processors as part of real-time systems makes it more [...]
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Configurable Air Transport
J. Snead

Collection of open conferences in research transport (2005). Vol. 2005, 14

Abstract
*This paper describes a concept of a large flying fuselage transport aircraft that carries the cargo or missionized payload in several large, detachable modules instead of carrying this cargo or payload internally as in current aircraft designs. The paper addresses the application of this concept to the global military airlift missions of air refueling, materiel transport, and persistent air power projection. The paper concludes with a brief discussion of the extension of this module-based aircraft design to other emerging military and commercial air transport needs.
Abstract
*This paper describes a concept of a large flying fuselage transport aircraft that carries the cargo or missionized payload in several large, detachable modules instead of [...]
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Distributed simulation: a proposed approach for air
J. Rehmann, P. Krois, A. Rehmann

Collection of open conferences in research transport (2005). Vol. 2005, 13

Abstract
This paper describes the use of distributed human-in-the-loop (HITL) simulation to address complex research questions about human performance requirements of future operational concepts and advanced technologies. Recent events in the Federal Aviation Administration (FAA) and associated research communities that support a move toward distributed simulation are reviewed. The risks of distributed simulation are discussed along with classes of fast time and human-in-the-loop simulation. Specific and candidate architectural requirements to achieve a distributed simulation capability are also described.
Abstract
This paper describes the use of distributed human-in-the-loop (HITL) simulation to address complex research questions about human performance requirements of future operational [...]
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Performance evaluation of a vision based lane tracker designed for driver assistance systems
J. McCall, M. Trivedi

Collection of open conferences in research transport (2005). Vol. 2005, 12

Abstract
Driver assistance systems that monitor driver intent, warn drivers of lane departures, or assist in vehicle guidance are all being actively research and even put into commercial production. It is therefore important to take a critical look at key aspects of these systems, one of which being lane position tracking. In this paper we present an analysis of lane position tracking in the context of driver support systems and examine previous research in this area. Using this analysis we present a lane tracking system designed to work well under a variety of road and environmental conditions. We examine what types of metrics are important for evaluating lane position accuracy for specific overall system objectives. A detailed quantitative evaluation of the system is presented in this paper using a variety of metrics and test conditions.
Abstract
Driver assistance systems that monitor driver intent, warn drivers of lane departures, or assist in vehicle guidance are all being actively research and even put into commercial [...]
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A framework for integrating disadvantaged analysis into transportation planning models
T. Yiğitcanlar, Y. Duvarcı

Collection of open conferences in research transport (2006). Vol. 2006, 18

Abstract
29th Australasian Transport Research Forum, ATRF 2006; Gold Coast, QLD; Australia; 27 September 2006 through 29 September 200 The ability to access personal or public transportation is fundamental for people to connect with employment opportunities, health and medical services, educational services, and the community at large. However certain populations lack the ability to provide their own transportation or have difficulty accessing whatever conventional public transportation may be available (Department of Transportation 2003). The ‘transportation disadvantaged’ populations are those persons who are unable to transport themselves or are unable to purchase transportation due to physical or mental disability, income status, or age. Therefore, the transportation disadvantaged are dependent upon others to obtain access to health care, employment, education, shopping, and other life sustaining activities. Additionally, since disadvantage is a personal experience, it can be simply characterised as what people perceive to be transportation disadvantage (Raje 2003).
Abstract
29th Australasian Transport Research Forum, ATRF 2006; Gold Coast, QLD; Australia; 27 September 2006 through 29 September 200 The ability to access personal or public transportation [...]
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A Comparison of Inherent Risk Levels in ASME B31.8 and UK Gas Pipeline Design Codes
J. Haswell, G. Goodfellow

Collection of open conferences in research transport (2006). Vol. 2006, 16

Abstract
The approach to gas pipeline risk and integrity management in the US, involving the development of integrity management plans for High Consequence Areas (HCA), is usually qualitative, as outlined in ASME B31.8S. Depending on the engineering judgement of the assessment team this can lead to a wide variety of results making risk comparison between pipelines difficult. Qualitative risk ranking methods are popular in Europe, but quantitative risk assessment (QRA) is also used for setting acceptable risk levels and as an input to risk and integrity management planning. It is possible to use quantitative risk assessment methods to compare the levels of risk inherent in different pipeline design codes. This paper discusses the use of pipeline quantitative risk assessment methods to analyse pipelines designed to ASME B31.8 and UK IGE/TD/1 (equivalent to PD 8010, published by BSI, for the design of gas pipelines) codes. The QRA utilises predictive models for consequence assessment, e.g. pipeline blowdown and thermal radiation effects, and failure frequency, in determining the risk levels due to an operational pipeline. The results of the analysis illustrate how the risk levels inherent in the two codes compare for different class locations & minimum housing separation distances. The impact of code requirements on design factor, depth of burial, population density and the impact of third party activity on overall risk levels are also discussed.Copyright © 2006 by ASME
Abstract
The approach to gas pipeline risk and integrity management in the US, involving the development of integrity management plans for High Consequence Areas (HCA), is usually [...]
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Finding Critical Traffic Matrices
Y. Zhang, Z. Ge

Collection of open conferences in research transport (2005). Vol. 2005, 10

Abstract
traffic matrix represents the amount of traffic between origin and destination in a network. It has tremendous potential utility for many IP network engineering applications, such as network survivability analysis, traffic engineering, and capacity planning. Recent advances in traffic matrix estimation have enabled ISPs to measure traffic matrices continuously. Yet a major challenge remains towards achieving the full potential of traffic matrices. In practical networking applications, it is often inconvenient (if not infeasible) to deal with hundreds or thousands of measured traffic matrices. So it is highly desirable to be able to extract a small number of "critical" traffic matrices. Unfortunately, we are not aware of any good existing solutions to this problem (other than a few ad hoc heuristics). This seriously limits the applicability of traffic matrices. To bridge the gap between the measurement and the actual application of traffic matrices, we study the critical traffic matrices selection (CritMat) problem in this paper. We developed a mathematical problem formalization after identifying the key requirements and properties of CritMat in the context of network design and analysis. Our complexity analysis showed that CritMat is NP-hard. We then developed several clustering-based approximation algorithms to CritMat. We evaluated these algorithms using a large collection of real traffic matrices collected in AT&T's North American backbone network. Our results demonstrated that these algorithms are very effective and that a small number (e.g., 12) of critical traffic matrices suffice to yield satisfactory performance.
Abstract
traffic matrix represents the amount of traffic between origin and destination in a network. It has tremendous potential utility for many IP network engineering applications, [...]
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Collapse Arrestors for Deepwater Pipelines: Finite Element Models and Experimental Validations for Different Cross-Over Mechanisms
A. Assanelli, R. Toscano, R. Chareau, L. Mantovano, E. Dvorkin, P. Amenta, D. Johnson

Collection of open conferences in research transport (2006). Vol. 2006, 13

Abstract
Using finite element models it is possible to determine the cross-over external pressure of different pipeline arrestor designs. In this paper these finite element models are discussed and validated by comparing their results with experimental determinations. The flipping and flattening cross-over mechanisms are considered in the experimental validation of the numerical models.Copyright © 2006 by ASME
Abstract
Using finite element models it is possible to determine the cross-over external pressure of different pipeline arrestor designs. In this paper these finite element models [...]
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Public transport development and equal access for all to urban amenities?
D. Caubel

Collection of open conferences in research transport (2006). Vol. 2006, 9

Abstract
Proceeding in CD ROM; The social dimension of urban transport policies becomes a paramount issue of the public action. This may result from the observed growth of social inequalities, and the persistence or even the worsening of segregation processes. In particular, this issue leads to questions about the access to activities and services that individuals need everyday. It also relates to the characterization of an equal access for all to the city."br /""br /"In this context, the aim of the paper is to validate, by the measure in the case of the Lyons conurbation, the existence of urban accessibility disparities between the richest and the deprived territories residents, by accounting for the private car and the public transport. We show that there are equal accesses to amenities by car, but the travel modes unequal access implies inequities in accessing urban activities. "br /""br /"Then, our paper analyses the social impacts of the public transport policy contents aiming at reducing the urban accessibility disparities or the gaps to the “standard society”. The assessment made, based on the interpretation of the Lyons Urban Travel Plan, accounts for concrete answers of the access to amenities improvement for everyone, and in particular for the underprivileged populations. Nevertheless, these answers prove to be limited. A public transport policy cannot claim to reduce the unequal access between territories and to fight against the exclusion of a minority of the population, without accounting for the local and overall contexts of urban morphology, without being in line with regional planning policies – in particular the activities location control policies.
Abstract
Proceeding in CD ROM; The social dimension of urban transport policies becomes a paramount issue of the public action. This may result from the observed growth of social inequalities, [...]
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Commercial Aircraft Fuel Efficiency Potential Through 2010
D. Greene

Collection of open conferences in research transport (2005). Vol. 2005, 7

Abstract
ft are second only to motor vehicles in the use of motor fuels, and air travel is growing twice as fast. Since 1970 air travel has more than tripled, but the growth of fuel use has been restrained by a near doubling of efficiency, from 26.2 seat miles per gallon (SMPG) in 1970 to about 49 SMPG in 1989. This paper explores the potential for future efficiency improvements via the replacement of existing aircraft with 1990's generation'' and post 2000'' aircraft incorporating advances in engine and airframe technology. Today, new commercial passenger aircraft deliver 50--70 SMPG. New aircraft types scheduled for delivery in the early 1990's are expected to achieve 65--80 SMPG. Industry and government researchers have identified technologies capable of boosting aircraft efficiencies to the 100--150 SMPG range. Under current industry plans, which do not include a post-2000 generation of new aircraft, the total aircraft fleet should reach the vicinity of 65 SMPG by 2010. A new generation of 100--150 SMPG aircraft introduced in 2005 could raise the fleet average efficiency to 75--80 SMPG in 2010. In any case, fuel use will likely continue to grow at from 1--2%/yr. through 2010. 20 refs., 2 figs., 2 tabs.
Abstract
ft are second only to motor vehicles in the use of motor fuels, and air travel is growing twice as fast. Since 1970 air travel has more than tripled, but the growth of fuel [...]
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Simplified methods for next generation IP access networks planning
A. García Gutiérrez, K. Hackbarth Planeta

Collection of open conferences in research transport (2006). Vol. 2006, 7

Abstract
The scope of this paper is to derive a set of simple formulas providing a traffic aggregation in important points of an Internet access networks. The paper shows that the resources associated to the access network depend on user type-, technology and service parameter. Existing calculation methodologies applies on individual approximations whereas this proposal exposes the combined application of these individual and wellknown approximations providing a scheme of generic dimensioning formulas. The dimensioning formulas for a generic applications are derived for the three main levels: connection, session and burst level, and the traffic aggregation is considered through three different and combined variables describing users, accesses and services forming a cube with three axes. The adaptation of corresponding parameters following the different axes allows the calculation of complete access network traffic scenarios, grouped by the so called CASUAL concept: Cube of Accesses / Services / Users. A set of CASUAL based tools allows an estimation of the aggregated traffic in different access points as multiplexers, IP point of presence or edge routers.
Abstract
The scope of this paper is to derive a set of simple formulas providing a traffic aggregation in important points of an Internet access networks. The paper shows that the [...]
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Burst Detection and Location in Water Transmission Pipelines
A. Simpson, G. Olsson, M. Lambert, D. Misiunas

Collection of open conferences in research transport (2005). Vol. 2005, 6

Abstract
This paper presents results from testing of a burst detection and location technique on a water transmission pipeline. The primary targets of the method are medium and large bursts that are the result of a sudden rupture of a pipe wall or other physical element in the pipeline system. The technique is based on the continuous monitoring of the pressure in the pipeline combined with a hydraulic transient modeling. Analysis of a burst-induced pressure transient wave and its reflections from the pipeline boundaries is used to derive the location and size of the burst. The method has earlier demonstrated promising results on a laboratory pipeline and a dead-end branch of a real water distribution network. Results presented here show that the approach has a potential to be used for burst detection and location in long transmission pipelines. Bursts of different sizes, locations and opening times were successfully detected and located. Different operational regimes of the pipeline were considered. The technique could help to minimize the response time to the pipe failure and therefore reduce the losses associated with a burst and improve reliability of the pipeline operation.
Abstract
This paper presents results from testing of a burst detection and location technique on a water transmission pipeline. The primary targets of the method are medium and large [...]
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Development of a Pipeline Surface Loading Screening Process
D. Warman, J. Hart, J. Chorney, M. Reed

Collection of open conferences in research transport (2006). Vol. 2006, 5

Abstract
Pipeline Operators receive numerous requests annually to cross their pipelines. In many of these cases detailed analysis using a number of different methods are performed since no simplified approach is available. The Canadian Energy Pipeline Association (CEPA) with Kiefner and Associates, Inc. undertook the development of a screening methodology for vehicle loading. The hope is a standard approach to these analyses might be established to assist pipeline operating companies. This paper describes an approach detailing the development and implementation of a simplified screening process to assess the effects of surface loads on buried pipelines. A design basis was established based on a literature review to identify theoretical models, standards, codes, and recommended practices that are currently used to assess the surface loading effects on buried pipelines. This design basis was incorporated into a methodology utilized to develop a screening tool which provides a simple “pass/no pass” determination and is based on attributes which are generally easy to obtain (e.g., wheel or axle load, ground surface loading pressure, depth of cover, maximum allowable operating pressure and design factor). Situations which pass the initial screening would require no additional analysis while situations that do not pass the initial screening may need to be evaluated on a more detailed basis. Simplified graphs have been developed to assist in additional screening prior to performing a more detailed evaluation.Copyright © 2006 by ASME
Abstract
Pipeline Operators receive numerous requests annually to cross their pipelines. In many of these cases detailed analysis using a number of different methods are performed [...]
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Dataflow Mini-Graphs: Amplifying Superscalar Capacity and Bandwidth
A. Roth, P. Prahlad, A. Bracy

Collection of open conferences in research transport (2005). Vol. 2005, 3

Abstract
mini-graph is a dataflow graph that has an arbitrary internal size and shape but the interface of a singleton instruction: two register inputs, one register output, a maximum of one memory operation, and a maximum of one (terminal) control transfer. Previous work has exploited dataflow sub-graphs whose execution latency can be reduced via programmable FPGA-style hardware. In this paper we show that mini-graphs can improve performance by amplifying the bandwidths of a superscalar processor's stages and the capacities of many of its structures without custom latency-reduction hardware. Amplification is achieved because the processor deals with a complete mini-graph via a single quasi-instruction, the handle. By constraining mini-graph structure and forcing handles to behave as much like singleton instructions as possible, the number and scope of the modifications over a conventional superscalar microarchitecture is kept to a minimum. This paper describes mini-graphs, a simple algorithm for extracting them from basic block frequency profiles, and a microarchitecture for exploiting them. Cycle-level simulation of several benchmark suites shows that mini-graphs can provide average performance gains of 2-12% over an aggressive baseline, with peak gains exceeding 40%. Alternatively, they can compensate for substantial reductions in register file and scheduler size, and in pipeline bandwidth.
Abstract
mini-graph is a dataflow graph that has an arbitrary internal size and shape but the interface of a singleton instruction: two register inputs, one register output, a maximum [...]
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Kentsel Lojistik Ve Lojistik Köy Uygulaması
R. Erdumlu

Collection of open thesis in transport research (2006). Vol. 2006, 21

Abstract
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006 Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2006 Bu çalışmada, Kentsel Lojistik ve Lojistik Köy kavramları ele alınıp, kentsel lojistik kavramı çerçevesinde geliştirilen optimum modelleme yöntemlerinin karşılaştırmalı olarak değerlendirilmesinin yapılması ve incelenen modeller neticesinde İstanbul’da organize lojistik bölge kurulumu için büyüklük ve lokasyon tayini hedeflenmiştir. Endüstriyel üretim alanları, organize sanayi bölgeleri, küçük sanayi bölgeleri ve kooperatifler, serbest bölge ve limanlar; yük üretim, tüketim ve geçiş noktaları kentsel alanların çevresinde yoğunlaşmaktadır. Bu durum, lojistik maliyetlerin yüksek olması, trafik ve gürültü gibi çevresel kirlilikler ve diğer verimsizliklere neden olmaktadır. Kesin Ağırlık Merkezi veya Taşıma Maliyetlerinin En Küçüklenmesi yöntemi ile yer seçimi kararı, taşıma modu, ağırlık ve mesafeye dayalı taşıma maliyetine bağlıdır. Bu modelde bilinenler, tedarik ve teslimat kaynaklarının koordinatları, yük miktarları ve bilinmeyen ise kurulacak Organize Lojistik Bölge’nin koordinatlarıdır. Bu problemde amaç fonksiyonu toplam taşıma maliyetinin minimum yapılması olarak tanımlanır. Elde edilen çözüm bize kurulması gereken OLB’nin koordinatlarını verecektir. Uygulama esnasında klasik algoritma ve yöntemlerin uygulanabilirliğinin sağlanabilmesi adına sınırlı sayıda nokta tespit edilmiş ve bu noktalar arasında OLB’nin tayini yapılmaya çalışılmıştır. In this study, optimum modelling techniques, which were developed for City Logistics, were examined comparatively including the discussion of Urban Logistics and Freight Village concepts. Moreover, determination of optimal location and size of such logistics terminals in Istanbul was aimed. Industrial production areas, industrial zones, small industrial zones and co-operative societies, free zones and ports; freight production, consumption and crossing points are on the increase in urban areas. This situation causes the high logistics costs, undesirable environmental factors such as traffic and high noise levels and other lacks of productivity. Determining optimal location with P-center problems or minimizing transportation costs methods are dependent on transmission mode, freight and transport costs that change with transmission distances. In these models, the coordinates of supply and delivery points and weights are known and coordinates of industrial zone are unknown. Objective function is described as minimizing total transmission costs. The solution set will give us the coordinates of the logistics terminal which is thougt to be build. This problem was studied with limited industrial zone and freight transport points in order to use the classical algorithms and methods and the coordinates of logistics terminal were calculated just considering these points. Yüksek Lisans M.Sc.
Abstract
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006 Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, [...]
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Routing, Protection and Traffic Engineering in WDM All-Optical Networks
M. Koubàa

Collection of open thesis in transport research (2005). Vol. 2005, 12

Abstract
This thesis mainly focuses on all-optical lightpaths establishment. We consider all along the thesis optical networks with finite resources, that is with a given maximum amount of wavelengths per fiber. Both exact and approximate optimization techniques are considered. In a first step, we investigate the problem of routing and wavelength assignment (RWA) considering permanent lightpath demands (PLDs) and develop ILPs (Integer Linear Programs) for both the routing and the wavelength assignment sub-problems. This work is then extend to deal with two classes of traffic demands referred to as scheduled lightpath demands (SLDs) and random lightpath demands (RLDs). On one hand, SLDs are characterized by pre-known dates of arrival and life durations. They may correspond for instance to a set of long term lightpath establishments in order to provide Optical Virtual Private Network services. On the other hand, RLDs are characterized by random arrival and life duration processes. In a second step, we deal with the routing and spare capacity assignment (RSCA) problem. Once again ILPs and heuritics are proposed to deal with the RSCA problem for PLDs, SLDs and RLDs. Due to the wavelength continuity constraint, a new lightpath demand may be rejected. In a third step, we focus on the improvement of the lightpath demand rejection ratio by means of lightpath rerouting strategies. We have developed such strategies in order to minimize traffic disruption on already routed demands. For each step, we have developed multiple optimization tools which have been applied to a wide range of network sizes, topologies and traffic scenarios. Our conclusions are then drawn based on these results.; Cette thèse porte essentiellement sur les problématiques fondamentales d'optimisation combinatoire qui se dégagent de la modélisation structurelle et algorithmique du dimensionnement des réseaux de transport WDM tout-optiques. L'optimisation de ces réseaux est nécessaire aux opérateurs de télécommunication, qui demandent la garantie d'une exploitation efficace des ressources déployées. La thèse est organisée en trois parties. La première partie traite du problème de routage et affectation de longueur d'onde. Nous proposons de résoudre le problème considérant des demandes de trafic permanentes. Des méthodes à la fois exactes basées sur la programmation linéaire et approchées ont été développées. Nous étendons ensuite le modèle de trafic pour considérer simultanément des demandes de trafic pré-planifiées et des demandes de trafic aléatoires. Différent algorithmes de routage ont été développés. Les différents algorithmes ont été comparés en terme de taux de rejet global. La deuxième partie concerne le problème de routage et affectation de longueurs d'onde avec protection. Les ressources dédiées à la protection sont rarement sollicitées, nous cherchons à en minimiser le nombre grâce au multiplexage des circuits optiques de protection. Des méthodes exactes et approchées sont encore une fois proposées considérant les demandes de trafic citées ci-dessus. La dernière partie présente un algorithme de reroutage de canaux optiques afin d'améliorer le taux de rejet dans les réseaux tout-optiques sans convertisseurs en longueurs d'onde. Plusieurs variantes de l'algorithme ont été proposées. Les résultats obtenus montrent un gain intéressant en terme de taux de rejet.
Abstract
This thesis mainly focuses on all-optical lightpaths establishment. We consider all along the thesis optical networks with finite resources, that is with a given maximum amount [...]
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The impact of bicycle lanes on critical gaps at unsignalised T-junctions /
Collection of open thesis in transport research (2006). Vol. 2006, 19

Abstract
Thesis (MEng(TransportSystemsEng))--University of South Australia, 2006. There is a significant gap in the current understanding of issues relating to bicycle safety. The provision of cycling facilities has long been based on professional opinion and has rarely been based on academic research. In particular, it is widely considered that the provision of bicycle lanes improves safety for cyclists, however there is little or no research to confirm this belief. This thesis seeks to improve the current understanding of the impact of bicycle lanes on safety by utilising gap acceptance theory. Unsignalised T-junctions have been surveyed to gather gap data for the estimation and comparison of critical gaps. The findings of this research indicate that bicycle lanes may in fact reduce safety at unsignalised intersections.
Abstract
Thesis (MEng(TransportSystemsEng))--University of South Australia, 2006. There is a significant gap in the current understanding of issues relating to bicycle safety. The [...]
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BGP-based interdomain traffic engineering
B. Quoitin

Collection of open thesis in transport research (2006). Vol. 2006, 18

Abstract
In a few years, the Internet has quickly evolved from a research network connecting a handful of users to the largest distributed system ever built. The Internet connects more than 20,000 Autonomous Systems (ASs) which are administratively independent networks. While the initial Internet was designed to provide a best-effort connectivity among these ASs, there is nowadays a growing trend to deploy new services such as Voice/Video over IP or VPNs. To support these emergent services, ASs need to better engineer their Internet traffic. Traffic Engineering encompasses several goals such as better spreading the traffic load inside a network and obtaining better end-to-end performance (lower latency or higher bandwidth)."br""br" Engineering the traffic inside a single AS is feasible and pretty well understood. To the opposite, interdomain traffic engineering is still a difficult problem. The main issue comes from the current Internet routing architecture, articulated around the Border Gateway Protocol (BGP). BGP propagates a subset of the Internet topology for scalability and stability reasons and does not optimize a single global objective. This limits the control each AS has on its routing and has dramatic implications for interdomain traffic engineering."br""br" In this thesis, we evaluate the primitive BGP-based routing control mechanisms. For this purpose, we designed and implemented a new approach for modeling BGP on large Internet-scale network topologies. Finally, to overcome the limitations of BGP in terms of routing control, we propose Virtual Peerings, a new mechanism based on a combination of BGP and IP tunneling. We apply Virtual Peerings to solve various interdomain traffic engineering problems such as balancing the load of Internet traffic received by an AS or decreasing the end-to-end latency of Internet paths. (FSA 3)--UCL, 2006
Abstract
In a few years, the Internet has quickly evolved from a research network connecting a handful of users to the largest distributed system ever built. The Internet connects [...]
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Not available
J. Chueire

Collection of open thesis in transport research (2005). Vol. 2005, 8

Abstract
Este trabalho trata da questão da segurança viária na cidade de São José do Rio Preto. É feito um diagnóstico da situação atual, à luz da composição e estrutura dos órgãos locais envolvidos, direta ou indiretamente, com o problema; do tratamento dado à segurança viária nas áreas de engenharia, educação e esforço legal; das informações obtidas em pesquisas de campo sobre o tráfego de veículos; e dos dados de acidentes de trânsito obtidos em levantamento efetuados. Também é proposto um plano de ações para o aumento da segurança viária na cidade, contemplando medidas diversas envolvendo os seguintes aspectos: maior segurança na circulação de pedestres, redução da velocidade de circulação dos veículos, melhoria da sinalização de trânsito, promoção de campanhas educativas contínuas, implementação de políticas educativas específicas para motociclistas, aperfeiçoamento da fiscalização, criação de um departamento específico para cuidar da segurança no trânsito dentro da Secretaria de Trânsito e Transportes, informatização dos dados e processamento das informações relativas aos acidentes de trânsito, avaliação do risco de acidentes utilizando auditoria de campo e técnica de conflitos de tráfego, implementação de ações efetivas nos campos de engenharia e esforço legal para reduzir os acidentes, melhoria do transporte público, etc. This work deals with the subject of traffic safety in the city of São José do Rio Preto. A diagnosis of the current situation, using the composition and structures of the local organs, direct or indirectly involved with the problem; of the treatment given to the traffic safety in the areas of engineering, education and legal effort; from the information obtained in field researches on the traffic of vehicles; and from the data of traffic accidents obtained is done in this work. A plan of actions is also proposed for the increase of the traffic safety in the city, considering several measures involving the following aspects : larger safety in the pedestrians\\'circulation, reduction of the speed of circulation of the vehicles, improvement of the traffic signs, promotion of continuous educational campaigns, implementation of specific educational politics for motorcyclists, improvement of the police actions, creation of a specific department of traffic safety in the Traffic and Transports Secretary, utilization of computer for processing the traffic accidents information, evaluation of accidents risk using field audit and traffic conflicts techniques, implementation of effective actions in the fields of engineering and legal effort to reduce the accidents, improvement public transportation, etc.
Abstract
Este trabalho trata da questão da segurança viária na cidade de São José do Rio Preto. É feito um diagnóstico da situação atual, à luz da composição e estrutura [...]
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The use of aaSIDRA software in modelling mixed-traffic flows at a signalized intersection case study in Hochiminh City, Vietnam /
Collection of open thesis in transport research (2006). Vol. 2006, 14

Abstract
Thesis (MEng(TransportSystemsEng)--University of South Australia, 2006. Mixed traffic, which is the typical type of traffic flow in Hochiminh city and other cities in Vietnam, brings a lot of issues to a traffic system, such as traffic congestion, delay and road safety. In order to deal with such issues, studies of mixed-traffic flows at intersections, which are the most vulnerable locations in the traffic network, are needed. There are various methods that have been used in this kind of study, in which the methods using traffic simulation software such as aaSIDRA appears to be the most effective. This thesis is going to model a signalized intersection in Hochiminh City using aaSIDRA software, which has never before been used to simulate mixed-traffic flows, with high proportion of motorcycles, at intersections. Due to constraints of time, only one hour of traffic data obtained at one signalized intersection in Hochiminh City is used for modelling in this research. In the modelling process, the output results estimated by aaSIDRA will be compared with the measured values to find the most appropriate model for the intersection. The final model for the studied intersection will be found by applying a calibration process, of which different passenger car equivalent (PCE) values for motorcycles are used in the calculations. Finally, all the required results will be analysed and discussed carefully. The performance of the intersection will be evaluated by analysing measures of performance such as degrees of saturation, delays, queue lengths and movement speeds available in the aaSIDRA output. Some useful recommendations will also be given to improve the accuracy and reliability of the model.
Abstract
Thesis (MEng(TransportSystemsEng)--University of South Australia, 2006. Mixed traffic, which is the typical type of traffic flow in Hochiminh city and other cities in Vietnam, [...]
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Congestion Inference and Traffic Engineering in Networks
V. Arya

Collection of open thesis in transport research (2005). Vol. 2005, 7

Abstract
This thesis focuses on problems related to Inference of Congestion in the Internet and Multicast Traffic Engineering in Overlay Networks. In the first part of the thesis, we propose methods which help to improve the quality of the congestion inference on both end-to-end paths and internal network links in the Internet. "br /"Today, transport protocols which transfer data in the Internet classify all packet losses as congestion. However, the development of various wireless access networks had led to the growth of wireless links in the Internet. Therefore, the packet losses observed by a transport protocol may have resulted either due to congestion or due to the presence of wireless links on the end-to-end path. In order to make best use of available network bandwidth, a transport protocol must reduce its sending rate only in response to congestion losses and not in response to wireless losses. In the second chapter of this dissertation, we consider the problem of differentiating congestion and wireless losses for unreliable transport protocols which transfer multimedia flows. Previously proposed end-to-end loss differentiation schemes chapter of this dissertation, we show efficient ways of encoding multicast trees within data packets. These encodings are almost optimal in terms of space and can be read and processed efficiently. They can be used to represent multicast trees within data packets to route multicast traffic on explicit trees in a stateless manner. We show the correspondence of multicast trees to theoretical tree data structures and obtain lower bounds on the number of bits needed to represent multicast trees.significantly misclassify wireless and congestion losses. We propose an explicit loss differentiation scheme which uses agents at the boundaries of wireless links and results in an accurate inference of congestion on the end-to-end path. We show how the agents can intelligently record the cause of packet losses within packets which are not lost, with low overhead. Inferring the level of congestion on internal network links or paths is useful for the purposes of monitoring and management of networks. The level of congestion on a link can be inferred by measuring the loss rate on that link. Installing or upgrading network elements to monitor internal links is an expensive process and hence the characteristics of internal links are often inferred from end-to-end measurements. "br /"The process of inferring characteristics of internal links from end-to-end measurements has come to be known as Network Tomography. One of the earliest proposed methods of performing network tomography is MINC (Multicast-based Inference of Network Characteristics), which infers loss rates (congestion) on internal network links using end-to-end multicast measurements. In MINC, per-link loss rates are inferred by analyzing binary feedbacks which are reported by multicast receivers in response to measurement probes sent from the source. However, due to the presence of buggy or malicious multicast receivers, feedbacks collected may be incorrect leading to a faulty inference of link loss rates. "br /"In the third chapter of this dissertation, we present a statistical verification procedure which can identify if the binary feedback data collected from receivers of a multicast tree contains incorrect feedbacks. The procedure does not require the knowledge of multicast tree topology and is able to identify incorrect data even in the presence of colluding receivers. "br /"In order to infer link characteristics from end-to-end multicast measurements, dedicated infrastructures to perform these measurements need to be deployed. For large scale multicast measurements, the task of deployment is complex and expensive. To avoid this, it was proposed to couple the process of reporting binary feedbacks for MINC loss inference with RTCP (Real-Time Control Protocol). "br /"In this passive measurement architecture, existing multicast sessions which use RTP (Real-Time Transport Protocol) to transfer their data can use their data packets as probes and report binary feedbacks needed for loss inference by piggy-backing them on RTCP packets. For loss inference, MINC requires receivers to report per probe binary feedbacks and this poses constraints since RTCP feedback bandwidth must not exceed 5% of data bandwidth. In the fourth chapter of this dissertation, we develop an extended MINC loss estimator which can perform loss inference using aggregate receiver feedbacks. Aggregate feedbacks require less feedback bandwidth and the estimator is able to perform loss inference using aggregate feedbacks without significant loss of accuracy. We also compare this estimator to the approach where MINC loss inference is performed using a reduced set of binary feedbacks. "br /"In the second part of the thesis, we propose a method which helps to perform multicast traffic engineering in overlay networks. In overlay networks, the network nodes which are generally servers can perform intelligent and adaptive networking functions which normally routers do not support. By studying the state of overlay paths, nodes can route traffic dynamically and perform load balancing or routing based on certain constraints. One of the tasks which overlay networks support is multicast routing. To make best use of the traffic conditions in the network, overlay nodes can route multicast traffic adaptively and achieve goals of traffic engineering. To be able to do so, they need mechanisms to choose specific or explicit multicast trees in the overlay. One way of routing traffic on explicit trees is to perform source routing, that is, to specify the tree within multicast data packets. In the fifth; Résumé non disponible en françai
Abstract
This thesis focuses on problems related to Inference of Congestion in the Internet and Multicast Traffic Engineering in Overlay Networks. In the first part of the thesis, [...]
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Theoretical and operational aspects of optimal airport arrival trajectories
F. Vormer

Collection of open thesis in transport research (2005). Vol. 2005, 6

Abstract
The thesis considers the trajectories that are used to guide aircraft from en-route flight to an airport. Although there is currently some room to adapt the trajectories to a specific situation, they are usually largely based on published standardised trajectories. In this study the potential of optimising the arrival trajectories using data about the current situation is investigated. A trajectory scheduling algorithm based on a multi-objective genetic optimisation algorithm is developed. Fast-time simulations are carried out for traffic arriving at Amsterdam Airport Schiphol. It is shown that optimising the arrival trajectories can increase throughput and has the potential of reducing impact on the environment significantly. Optimising the arrival trajectories may have implications for the pilots and air traffic controllers tasks though. It is studied by means of experiments in a flight simulator how the shape of the trajectory influences the task demand load imposed on the pilot. A number of metrics are proposed to describe the task demand load. Off-line analyses using these metrics indicate that task demand load may increase when optimised arrival trajectories are used instead of standard trajectories. It is shown though that recently proposed displays for the flight deck that give 4-D guidance information may help to reduce the task demand load. In addition, the task demand load imposed on air traffic controllers is assessed with metrics describing airspace complexity. Off-line analyses indicate that task demand load for air traffic controllers may increase in case conventional air traffic control is maintained.
Abstract
The thesis considers the trajectories that are used to guide aircraft from en-route flight to an airport. Although there is currently some room to adapt the trajectories to [...]
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A microsimulation model of travel choices for use in transport corridor analysis /
Collection of open thesis in transport research (2006). Vol. 2006, 12

Abstract
Thesis (PhD)--University of South Australia, 2006. The aim of this research project is to improve our understanding of how planning policies, which seek to influence patterns of land use and activities, can promote changes in travel behaviour towards 'more sustainable transport', with particular reference to metropolitian transport corridors.
Abstract
Thesis (PhD)--University of South Australia, 2006. The aim of this research project is to improve our understanding of how planning policies, which seek to influence patterns [...]
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Safety Culture in Sea and Aviation Transport
Å. Ek

Collection of open thesis in transport research (2006). Vol. 2006, 10

Abstract
The research presented in this thesis investigates sea and aviation transport safety culture, with a focus on perceptions and attitudes. A safety culture reflects the attitudes, beliefs, perceptions, and values that individuals share in relation to safety. Safety culture is often identified as being essential to an organization's ability to manage safety-related aspects of its operations. The aims of this research are: to assess individual perceptions and judgments of safety culture in practical contexts by using nine aspects of safety culture found in the safety culture literature; to increase knowledge about the safety culture aspects by conducting comparative studies in three transport branches; and to investigate relationships between safety culture aspects and organizational climate dimensions. The approach to safety culture presented in this thesis focuses on good organizational learning and investigates nine aspects: Learning, Reporting, Justness, Flexibility, Communication, Attitudes towards safety, Safety-related behaviours, Risk perception, and Working situation."br /" "br /" Studies were conducted in airport ground handling (one site), passenger shipping (six ships), and air traffic control (three sites), where the safety culture was assessed using observations, questionnaire packages, interviews, and collection of facts. In total, 949 subjects completed a questionnaire package containing nine scales, one for each safety culture aspect, and 80 interviews were conducted. Ekvall's organizational climate questionnaire, which focuses in part on an organization's ability for innovation and change, was completed by 719 subjects."br /" "br /" The nine scales representing the nine safety culture aspects were found to function well with good reliability in the three transport settings, and may constitute valuable methods for monitoring and improving safety culture in working environments. Obtaining both questionnaire data (the nine scales) and interview data was valuable; the questionnaire package provided comparative data across transport branches and allowed establishment of reference data concerning safety culture aspects in each of the three branches. The interviews provided knowledge and examples of positive and negative expressions of safety culture that the interviewees had experienced."br /" "br /" The comparative studies of safety culture aspects were conducted using a multiplex approach of data collection, which provided valuable knowledge about safety culture in practical contexts."br /" "br /" The comparisons of average scores for the nine safety culture aspects showed that air traffic control often had somewhat higher average scores than the other two branches, while the ground handling ramp organization generally had the lowest average scores."br /" "br /" Compared to employees, managers generally had somewhat more positive perceptions and judgments of safety culture aspects, but the two groups differed very little in their perceptions and judgments of the organizational climate. Managers? expectations and goals concerning safety culture aspects were compared to employees? actual questionnaire scores. Employees? reports of the safety culture aspects were often poorer than both managers? estimations of reality and managers? lower acceptable limits for safety culture aspect scores."br /" "br /" Individual characteristics, such as gender, age, and time in company, were found to have very little effect on how the safety culture aspects were perceived and judged."br /" "br /" The organizational climate on board three passenger/cargo ships was found to be somewhere in between the normative ?innovative? and the ?stagnating? organization types, and very often closer to the ?stagnating? type. The organizational climate at each of the three air traffic control sites was similar to the climate in ?innovative? organizations."br /" "br /" Relationships existed between safety culture aspects and organizational climate dimensions. In passenger shipping, better Challenge/Motivation among personnel and a higher level of Support for ideas were significantly positively related to most safety culture aspects. In air traffic control, a higher level of Support for ideas and a lower level of Conflicts were significantly positively related to many safety culture aspects."br /" "br /" The results show that learning processes are better developed in the air traffic control setting than in passenger shipping and airport ground handling ramp activities. Compared to the other two branches, air traffic control can be characterized by a more mature approach to reporting anomalies and by having a more developed procedure for analysing limitations and implementing improvements."br /" "br /" Further research in the safety culture field should concentrate on developing methods for assessing the behavioural and situational areas of safety culture; testing the relation of safety culture to safety management and safety behaviour; determining which aspects and items are important for measuring safety culture; and finding indications of what elements influence safety behaviours, and how they exert this influence. I forskningsarbetet som presenteras i denna avhandling har säkerhetskulturen studerats inom sjö- och flygtransportbranscherna med fokus på individers attityder och uppfattningar om säkerhetskulturen. En säkerhetskultur avspeglar de attityder, uppfattningar och värderingar som individer i en organisation delar när det gäller säkerheten. Säkerhetskulturen identifieras ofta vara grundläggande för en organisations förmåga att hantera säkerhetsrelaterade aspekter. Målsättningarna med forskningsarbetet har varit: att i praktiska sammanhang undersöka individers uppfattningar och bedömningar av nio aspekter av en säkerhetskultur vilka återfinns i litteraturen inom forskningsområdet; att få ökad kunskap om de nio säkerhetskulturaspekterna genom att genomföra jämförande studier i tre transportbranscher; att undersöka relationer mellan säkerhetskulturaspekterna och dimensioner i organisationsklimatet. Den säkerhetskulturansats som presenteras i avhandlingen fokuserar på gott organisatoriskt lärande och undersöker nio aspekter: Lärande, Rapporterande, Rättvisa, Flexibilitet, Kommunikation, Attityder till säkerhet, Säkerhetsrelaterade beteenden, Riskperception och Arbetssituation."br /" "br /" Studier genomfördes i följande branscher: inom en rampverksamhet på flygplats, inom passagerarsjöfart (sex fartyg) och inom flygtrafikledning (tre enheter). Säkerhetskulturen studerades genom att använda observationer, frågeformulärpaket, intervjuer och insamling av fakta. Totalt fyllde 949 subjekt i frågeformulärpaketet som innehöll nio frågeformulär (en för varje säkerhetskulturaspekt) och 80 intervjuer relaterade till säkerhetskulturen genomfördes. 719 subjekt fyllde i Ekvalls organisationsklimatfrågeformulär vilket delvis fokuserar på att mäta en organisations förmåga till innovation och förändring."br /" "br /" De nio frågeformulären som representerade de nio säkerhetskulturaspekterna visade sig fungera bra (med god reliabilitet) i de tre transportbranscherna, och kan utgöra värdefulla metoder för att monitorera och förbättra säkerhetskulturen i praktiska sammanhang. Att samla in data genom både frågeformulär och intervjuer var värdefullt; frågeformulärpaketet gav data som tillät jämförelse mellan transportbranscher och en möjlighet att skapa ett referensmaterial inom varje transportbransch. Intervjuerna gav kunskap om och exempel på positiva och negativa yttringar av säkerhetskulturen som de intervjuade hade fått erfarenhet av."br /" "br /" Jämförelser av de nio säkerhetskulturaspekternas medelvärden visade att flygtrafikledningen ofta hade något högre medelvärden jämfört med de andra två branscherna, medan ramporganisationen generellt sett hade de lägre medelvärdena."br /" "br /" Jämfört med anställda så hade ledare generellt sett mer positiva uppfattningar om säkerhetskulturaspekterna, men de två grupperna skiljde sig mycket litet åt i hur man uppfattade organisationsklimatet. Ledares förväntningar och mål när det gällde säkerhetskulturaspekterna jämfördes med anställdas verkliga värden på säkerhetskulturaspekterna erhållna från frågeformulärdata. De värden/bedömningar som anställda gav för säkerhetskulturaspekterna var ofta lägre/sämre än både ledares uppskattning av verkligheten och ledares lägsta acceptabla gräns för värden på säkerhetskulturaspekterna."br /" "br /" Individfaktorer som kön, ålder, tid i företaget visade sig ha liten effekt på hur säkerhetskulturaspekterna uppfattades och bedömdes."br /" "br /" Organisationsklimatet som studerades ombord på tre av de sex fartygen kunde till sin karaktär placeras mellan de normativa ?innovativa? och ?stagnerade? organisationstyperna, och ofta närmare den ?stagnerade? typen."br /" "br /" Organisationsklimatet inom de tre enheterna inom flygtrafikledningen var i huvuddrag mest lik klimatet i ?innovativa? organisationer."br /" "br /" Man kunde hitta relationer mellan säkerhetskulturaspekterna och organisationsklimatdimensionerna. Inom passagerarsjöfarten var bättre Utmaning/Motivation hos personalen och ett bättre Idéstöd signifikant positivt relaterat till de flesta säkerhetskulturaspekterna. Inom flygtrafikledningen, var ett bättre Idéstöd och färre Konflikter signifikant positivt relaterade till många säkerhetskulturaspekter."br /" "br /" Resultaten visade att processer för lärande är bättre utvecklade inom flygtrafikledningen än inom passagerarsjöfart och rampverksamhet. Jämfört med de andra två branscherna, kan flygtrafikledningen karakteriseras ha en mer mogen ansats till att rapportera anomalier och ha en mer utvecklad process för att analysera och implementera förbättringar."br /" "br /" Fortsatt forskning inom säkerhetskulturområdet bör fokusera på att utveckla metoder för att mäta beteendeelement och systemelement hos en säkerhetskultur; testa relationen mellan säkerhetskultur, säkerhetshantering och säkerhetsbeteenden; bestämma vilka aspekter och specifika frågor som är viktiga vid mätning av säkerhetskultur; samt söka finna vilka komponenter som påverkar säkerhetsbeteenden och hur dessa komponenter utövar sitt inflytande på säkerhetsbeteenden.
Abstract
The research presented in this thesis investigates sea and aviation transport safety culture, with a focus on perceptions and attitudes. A safety culture reflects the attitudes, [...]
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A Framework for Evaluation and Design of an Integrated Public Transport System
C. Häll

Collection of open thesis in transport research (2006). Vol. 2006, 9

Abstract
Operators of public transport always try to make their service as attractive as possible, to as many persons as possible and in a so cost effective way as possible. One way to make the service more attractive, especially to elderly and disabled, is to offer door-to-door transportation. The cost for the local authorities to provide this service is very high and increases every year. To better serve the needs of the population and to reduce the cost for transportation of elderly and disabled, public transportation systems are evolving towards more flexible solutions. One such flexible solution is a demand responsive service integrated with a fixed route service, together giving a form of flexible public transport system. The demand responsive service can in such a system be used to carry passengers from their origin to a transfer location to the fixed route network, and/or from the fixed route network to their destination. This thesis concerns the development of a framework for evaluation and design of such an integrated public transport service. The framework includes a geographic information system, optimization tools and simulation tools. This framework describes how these tools can be used in combination to aid the operators in the planning process of an integrated service. The thesis also presents simulations made in order to find guidelines of how an integrated service should be designed. The guidelines are intended to help operators of public transport to implement integrated services and are found by evaluating the effects on availability, travel time, cost and other service indicators for variations in the design and structure of the service. In a planning system for an integrated public transport service, individual journeys must in some way be scheduled. For this reason the thesis also presents an exact optimization model of how journeys should be scheduled in this kind of service. "p"Report code: LiU-TEK-LIC- 2006:38
Abstract
Operators of public transport always try to make their service as attractive as possible, to as many persons as possible and in a so cost effective way as possible. One way [...]
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Organizational Psychology and Safety Culture in Air Traffic Control: Concerning Organizational Climate, Situational Leadership and Psychosocial Work Environment
M. Arvidsson

Collection of open thesis in transport research (2006). Vol. 2006, 8

Abstract
The air traffic control industry in Europe is under mounting pressure due to increasing air traffic and inefficient routines caused by a fragmented air space. In order to handle the demands the European Commission has launched a program entitled the Single European Sky initiative which seeks to promote a more efficient way of handling the air traffic over Europe. A reorganization of air traffic management will be introduced during this process and air traffic control centers in Europe will be merged. New tech-nology will further be implemented and the air space will be rationalized. In this context the Swedish air traffic control provider is an interesting case since an adaptation to increasing air traffic and the Single European Sky initiative has already begun through the introduction of new organizational structures and new technology."br /" "br /" As psycho-organizational aspects can be identified as affecting safety out-comes in high risk organizations with highly reliable operations, the overall aim of the research presented in this thesis was to study different psycho-organizational aspects in Swedish air traffic control during times of change. The studies on which this thesis is based focused on: innovative organizational climate, examining the innovative preparedness and capacity to cope with changes in a highly regulated organizational environment; situational leader-ship, examining leadership characteristics in a high risk organization with a well developed safety culture; psychosocial work environment, examining critical psychosocial environmental factors in a high risk organization with de-manding work operations; and safety culture, examining perceptions of safety culture as well as the relationships between safety culture aspects and or-ganizational climate dimensions."br /" "br /" All in all, five studies were conducted of which four were empirical. The empirical studies were all conducted at two air traffic control centers and an administrative air traffic services (ANS) unit which was part of the LFV Group Swedish Airports and Air Navigation Services. The three study loca-tions employed 635 air traffic controllers and other staff members. The or-ganizational climate was measured with the Creative Climate Questionnaire (CCQ) (Ekvall, 1990), the situational leadership with the Leader Effectiveness and Adaptability Description (LEAD) (Hersey & Blanchard, 1988; Holmkvist, 2000), the psychosocial work environment with the Copenhagen Psychosocial Questionnaire (COPSOQ) (Kristensen, Hannerz, Høgh & Borg, 2005), and the safety culture with the safety culture assessment questionnaire devel-oped by Ek (2006)."br /" "br /" Study I concluded that the existing empirical research concerning relation-ships between organizational climate, leadership and safety culture or safety climate is limited. Previous research supports the assumption that safety culture is related to other psycho-organizational aspects, but the knowledge base is still too limited to be conclusive. The ambiguity in defining and op-erationalizing the concepts is an additional weakness in the field."br /" "br /" It was further assumed that the innovative organizational climate would be under-developed in air traffic control due to the strict regulatory framework which is present in this environment. The results from Study II revealed, however, that the innovative organizational climate was quite positive in spite of the rule governed work. Differences in the assessment of the inno-vative organizational climate could be identified according to work charac-teristics and work tasks but not according to organizational position."br /" "br /" Study III concluded that the situational leadership characteristics differed according to situation. The leadership behavior was more relationship-oriented in Success and Group situations compared with Hardship and Individual situations. The leadership adaptability ? the leader's ability to adjust leader-ship style according to the situation ? was superior in Success and Individual situations than in Hardship and Group situations. Operational conditions, lead-ership structures and working tasks were, on the other hand, not associated with leadership behavior."br /" "br /" Three aspects of the psychosocial work environment were identified as dif-ficult in air traffic control in Study IV. In an otherwise positive assessment, Sensorial demands, Freedom and Feedback were challenging aspects. These as-pects seemed to be characteristic for operative air traffic control work since the operative personnel assessed them to be statistically significantly less positive than did the administrative personnel. Organizational position was also found to be influential in the assessment of psychosocial work envi-ronmental factors since the management group made more positive as-sessments on a number of dimensions. The effect of differences in opera-tional conditions was, however, limited."br /" "br /" The safety culture was positively assessed in the Swedish air traffic control context according to Study V. The administrative ANS unit had generally somewhat lower scores than the two operative air traffic control centers. Overall, Communication, Justness and Flexibility received slightly lower scores than the rest of the safety culture aspects. The results further demonstrated that the two organizational climate dimensions, Support for ideas and Conflicts, were positively and most frequently related to the various safety culture as-pects at the two air traffic control centers. However, few relationships were found between the safety culture and organizational climate concepts at the administrative ANS unit."br /" "br /" Because of the limited knowledge concerning the influence of organiza-tional aspects on safety and their possible relationships with safety culture and safety climate, more research in this area is desired, especially in the field of air traffic control. Due to differences in national conditions and culture as well as local variations, studies similar to those conducted in Sweden are also needed in other European countries in order to make the transition to the Single European Sky as smooth, safe and efficient as pos-sible. Föreliggande avhandling behandlar organisatoriska aspekter såsom organi-sationsklimat, psykosocial arbetsmiljö, situationsanpassat ledarskap samt säkerhetskultur inom den svenska flygtrafikledningen."br /" "br /" Avhandlingen är en del av ett större forsknings- och utvecklingsprojekt ? Human Factors in Air Navigation Services (HUFA) ? som drivs i samarbe-te mellan det svenska Luftfartsverket och Lunds universitet. Bakgrunden till projektet är att flygtrafiktjänsten i dag är föremål för stora förändringar. Flygledningscentralerna vid Malmö-Sturup och Stockholm-Arlanda har ny-ligen genomgått betydande organisationsförändringar samt infört ny teknik. Förändringarna har initierats som ett led i en internationell harmoniserings-process där målet är att möta ökande trafikvolymer. Det europeiska luft-rummet är idag till stora delar uppdelat efter nationsgränser, vilket ger ett fragmenterat luftrum med många luftrumssektorer som inte tillåter en op-timering av flygtrafikflödena. Då prognoser gör gällande att flygtrafiken kommer att fördubblas fram till år 2020 och systemet redan idag är överbe-lastat har Europakommissionen initierat ett projekt kallat ?Single European Sky? som syftar till att effektivisera flygledningsarbetet bl.a. genom att re-ducera antalet flygledningscentraler och skapa ett gemensamt Europeiskt övre luftrum. Flera flygledningscentraler kommer därför att slås samman med krav på nya organisationsstrukturer, ny teknik och nya luftrumsindel-ningar."br /" "br /" Tidigare forskning har påvisat att t.ex. organisationsförändringar kan ha negativ inverkan på säkerheten i organisationer vars verksamhet karaktäri-seras av många riskfaktorer. Sedan tidigare är det också känt att organisa-tioner vars verksamhet i stor utsträckning styrs av instruktioner, regler och rutiner har svårt att skapa ett gynnsamt förändringsklimat. Säkerhetskultur och innovativt organisationsklimat är därför två centrala aspekter som av-handlingen behandlar. Man har också tidigare konstaterat att ledarskapet har stor betydelse för säkerhetskulturen där ledarnas engagemang, attityder och beteende i relation till säkerheten påverkar övriga medarbetares upp-fattningar, attityder och beteende osv. Man vet också att psykosociala fak-torer kan inverka på individens arbetsprestationer där t.ex. stress kan vara en orsak till slarv och misstag. Förändringar är också en extra belastning som kan få effekter för säkerheten i ett redan krävande arbete."br /" "br /" Tidigare forskning kring säkerhet och säkerhetsbeteende har i första hand satt fokus på individfaktorer som kritiska determinanter vid incidenter och avvikelser. Omfattande forskningsinsatser märks kring utformning av gränssnitt, rutiner och arbetsprocedurer osv. Under senare år kan dock ett trendskifte identifieras där psyko-organisatoriska aspekter som säkerhets-kultur ägnas allt mer uppmärksamhet som viktiga faktorer för säkerheten i högriskorganisationer. Organisatoriskt lärande, attityder, tillit och rättvisa är exempel på psyko-organisatoriska dimensioner som anses viktiga i en sä-kerhetskultur. Dock verkar sambanden mellan säkerhetskulturen och andra psyko-organisatoriska aspekter dåligt utforskad. Då säkerhetskulturen anses utgöra en del av det övergripande klimatet på arbetsplatsen är det rimligt att tro att såväl organisationsklimat som ledarskap och psykosocial arbetsmiljö på något sätt relaterar till säkerhetskulturen och i någon utsträckning också påverkar denna. Begreppet säkerhetskultur antyder att det utgör en del av en mer övergripande organisationskultur även om relationerna mellan sä-kerhetskultur och organisationskultur inte är helt klara. Det ifrågasätts om det är klokt att separera säkerhetskulturen från den övergripande kultur som existerar i anslutning till den övriga verksamheten. Beroendet är myck-et starkt då dessa är i förbindelse genom allmänna arbetsprocesser och or-ganisatoriska faktorer. Den övergripande produktionskvaliteten anses också hänga samman med kvaliteten på säkerhetsarbetet. Detta till trots verkar ledarskapets relationer till säkerhetskulturen vara det enda område som är väl utforskat. Någon enstaka studie har fokuserat kring relationerna mellan organisationsklimat och säkerhetsklimat där samband mellan ett allmänt organisationsklimat och säkerhetsklimat har kunnat påvisas."br /" "br /" Projektet involverar tre enheter inom Luftfartsverket med sammanlagt 635 anställda. Av dessa enheter är två operativa flygledningscentraler, där den ena i huvudsak hanterar överflygande trafik sk. en route, (här omnämnd som överflygningscentralen) och den andra i huvudsak betjänar flygtrafik på väg till och från flygplatser sk. arrival and depature (här omnämnd som start- och landningscentralen). Utöver de operativa flygledningscentralerna ingår ock-så en administrativ enhet vid Luftfartsverkets huvudkontor kallat ANS (Air Navigation Services)."br /" "br /" Avhandlingen omfattar sammantaget fem olika studier där Studie I är en teoretisk litteraturstudie som behandlar relationer mellan organisationskli-mat, ledarskap och säkerhetskultur och säkerhetsklimat. Studie II-V bygger på empiriskt material insamlat vid de ovan nämnda flygledningscentralerna och ANS."br /" "br /" Avsikten med Studie I var att genom en litteraturstudie undersöka vilken empirisk kunskap som finns med avseende på relationer mellan organisa-tionsklimat och säkerhetsklimat eller säkerhetskultur. Avsikten var också att studera i vilken utsträckning och på vilket sätt etablerade ledarskapsteorier har tillämpats inom säkerhetsforskningen för att undersöka påverkanspro-cesser och relationer mellan ledarskap och säkerhetskultur eller säkerhets-klimat. Av de sammanlagt nio undersökningar som var föremål för gransk-ning behandlade fyra relationer mellan organisationsklimat och säkerhets-klimat eller säkerhetskultur, där i samtliga fall samband mellan de undersök-ta aspekterna kunde konstateras. De övriga fem undersökningarna behand-lade ledarskapets betydelse för säkerheten. Ledarskapsteorier som introdu-cerades i dessa undersökningar var transaktionellt och transformellt ledar-skap, utbytesteorier samt ledarskapsstil. Den övergripande slutsatsen som kunde dras från denna litteraturstudie var att även om samtliga granskade undersökningar bidrog med nyttig kunskap inom området finns fortfarande behov av mer forskning. Vissa problem kunde också identifieras med avse-ende på generaliserbarhet, definition av begrepp, operationalisering och grundläggande vetenskaps teoretiska utgångspunkter."br /" "br /" Syftet med Studie II var att undersöka beredskapen att möta förändringar i en verksamhet som till stora delar omgärdas av regler och rutiner genom att studera det innovativa organisationsklimatet. De övergripande resultaten påvisade ett klimat som trots den regelstyrda verksamheten var förhållan-devis positivt. Resultaten visade också att personalen vid start- och land-ningscentralen uppfattade det innovativa klimatet som något mer positivt än personalen vid överflygningscentralen. De olika operationella förutsätt-ningarna kan därför anses spela en roll för klimatet. ANS bedömde vidare organisationsklimatet som något positivare i jämförelse med överflygnings-centralen samt något negativare än start- och landningscentralen. Resultaten kunde också visa att olika arbetsuppgifter inverkade på uppfattningen av organisationsklimatet då den administrativa personalen i vissa avseenden gjorde en signifikant mer positiv bedömning av klimatet. Vidare kunde konstateras att organisatorisk position i termer av chef eller medarbetare inte hade någon inverkan på hur organisationsklimatet uppfattades."br /" "br /" Studie III syftade till att undersöka det situationsanpassade ledarskapet i en högriskmiljö med väl utvecklad säkerhetskultur. Ledarskapet operationalise-rades i termer av ledarstil, stilanpassning samt över- och understyrning och studerades utifrån fyra olika situationer - utveckling, motgång, grupp och individ. Resultaten visade att situationen har stor inverkan på ledarskapet. Ledarskapsstilarna var signifikant olika i de undersökta situationerna. Le-darskapsstilen var mer relationsorienterad i framgångs- och gruppsituatio-ner än i motgångs- och individsituationer. Stilanpassningen ? ledarens för-måga att anpassa sitt ledarskap till medarbetarnas erfarenhet och vilja att ta ansvar ? var statistiskt signifikant bättre i utvecklings- och individsituationer jämfört med motgångs- och gruppsituationer. Skillnaden i operativa förut-sättningar mellan flygledningscentralerna verkade dock inte ha någon inver-kan på ledarskapet."br /" "br /" Studie IV avsåg att undersöka den psykosociala arbetsmiljön inom flygled-ningen med avseende på krav, inflytande, stöd och stress. De övergripande resultaten gav en bild av en tämligen positiv arbetsmiljö. Utmärkande nega-tivt för flygtrafikledning verkar dock vara Sensoriska krav, Feedback och Fri-hetsgrader, som alla bedömdes vara problematiska i arbetet. De olika opera-tionella förutsättningarna mellan flygledningscentralerna gav inga signifi-kanta skillnader i arbetsmiljö. Skillnad i arbete verkar däremot ha betydelse då den operativa personalen uppfattade Sensoriska krav, Inflytande, Feedback och Frihetsgrader som mindre positiva och Kvantitativa krav och Sociala relatio-ner som mer positiva jämfört med den administrativa personalen. Tydliga skillnader framkom också i jämförelsen av position, där chefer i allmänhet uppfattade arbetsmiljön som mer positiv än icke-chefer."br /" "br /" Den femte studiens övergripande syfte var att undersöka säkerhetskulturen inom svensk flygtrafikledning. De övergripande resultaten visade att säker-hetskulturen i stort bedömdes vara överrensstämmande mellan de olika un-dersökta enheterna. ANS gav dock generellt sett något lägre bedömningar. Det kunde också konstateras att chefer i allmänhet ansåg säkerhetskulturen som bättre utvecklad jämfört med övrig personal. Individuella faktorer som kön, ålder, anställningstid hade däremot liten eller ingen effekt på uppfatt-ningen av säkerhetskulturen. Studien avsåg också att undersöka relationen mellan organisationsklimatet och säkerhetskulturen. På flygledningscentra-lerna kunde samband konstateras mellan i huvudsak organisationsklimat-dimensionerna Idéstöd och Konflikter och säkerhetskulturen, medan inga starka samband kunde identifieras vid ANS. Säkerhetskulturen visade sig också vara stabil under en 20-månadersperiod. Vid en intervjustudie visade resultaten att en väl utvecklad rapporteringskultur kan identifieras vid de undersökta flygledningscentralerna. Dialogen bedömdes som öppen och rättvis i vilken operatörerna kan dela sina erfarenheter utan rädsla för re-pressalier."br /" "br /" Då kunskapen kring hur organisatoriska aspekter inverkar på säkerheten i en högriskmiljö och relationerna kring organisatoriska faktorer och säker-hetskultur och säkerhetsklimat fortfarande är oklara, efterlystes mer forsk-ning inom detta område, med ett särskilt fokus på flygtrafikledning. För att övergången till Single European Sky skall kunna genomföras så smidigt, säkert och effektivt som möjligt bör också liknande studier som de i av-handlingen behandlade genomföras i fler europeiska länder, då kulturella skillnader och lokala variationer sannolikt påverkar övergången.
Abstract
The air traffic control industry in Europe is under mounting pressure due to increasing air traffic and inefficient routines caused by a fragmented air space. In order to [...]
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Traffic signal co-ordination on Pultney Street using Paramics V5.2 /
Collection of open thesis in transport research (2006). Vol. 2006, 7

Abstract
Thesis (MEng(TransportSystemsEng))--University of South Australia, 2006. Includes bibliographical references : leaves 66-67. Introduction -- Literature review -- Research methodology -- Analysis and discussion -- Conclusions and recommendations -- Future works.
Abstract
Thesis (MEng(TransportSystemsEng))--University of South Australia, 2006. Includes bibliographical references : leaves 66-67. Introduction -- Literature review -- Research [...]
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Air Traffic Control in Sweden : Differences between a public and private alternative in an upcoming deregulation
J. Löfmark, L. Saleh, D. Zand

Collection of open thesis in transport research (2006). Vol. 2006, 6

Abstract
Background: In Sweden, air traffic control is currently performed in a mo-nopoly with the state owned Luftfartsverket as the only sup-plier. A deregulation process has been initiated with the ration-ale of cost reductions, both for airports and airline passengers. Problem and purpose: Economic arguments have been predominant for this potential deregulation and the underlying assumptions are that private al-ternatives would improve efficiency and reduce costs. This has lead the authors to identify what private alternatives would do differently than the current public operator in order to offer these benefits. Method: To fulfill the purpose the authors have used a qualitative ap-proach based on interviews with the current public operator as well as a new potential private alternative. In addition to this, interest organizations and regulative agencies have been con-tacted and secondary data incorporated to provide a holistic perspective. Conclusion: The authors have identified differences in activities between a public and private alternative that would create an advantageous effect on the market. They are: a different management of re-tirement funds, prolonged retirement age, new compensation system, altered recruitment policy, a full utilization of staff and a seizing of non-value adding activities.
Abstract
Background: In Sweden, air traffic control is currently performed in a mo-nopoly with the state owned Luftfartsverket as the only sup-plier. A deregulation process has been [...]
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Interdomain traffic engineering with MPLS
C. Pelsser

Collection of open thesis in transport research (2006). Vol. 2006, 5

Abstract
During the last years, MultiProtocol Label Switching (MPLS) has been deployed by most large Service Providers (SP). The main driver for MPLS deployment is the ability to provide new services with stringent Service Level Agreements (SLAs) such as layer-2 and layer-3 Virtual Private Networks (VPNs) as well as Voice and Video over IP. Most of these services are already deployed inside single SP networks. However, customers now require world-wide VPN and VoIP services. Therefore, SPs need to collaborate to offer these services across multiple SP networks. Inside a single SP network, each node usually knows the complete topology of the network with the load and delay of all the links. Based on this information, each router is able to compute constrained paths toward any other router inside the SP network. Then, it can establish a connection and reserve resources along the computed path with the Resource reSerVation Protocol (RSVP-TE). However, when services with stringent requirements must cross multiple SP networks the computation of the path becomes a problem. Routers in different SP networks exchange routing information by using the Border Gateway Protocol (BGP). BGP provides reachability information. It does not distribute complete topology, delay and bandwidth information. One way to provide guaranteed services crossing different SPs is to delegate the computation of the paths to a Path Computation Element (PCE) that learns the topology of the different SPs. However, this requires that SPs reveal information that they usually consider confidential, their topology. In this thesis, we perform active measurements to show the difficulty to engineer the interdomain traffic with BGP. MPLS together with RSVP-TE provide much more control on the traffic. We define extensions to RSVP-TE for the protection of inter-AS MPLS paths. The aim is to be able to provide the same service guarantees as inside a domain while keeping the internal topology of SPs confidential, as required by SPs. We propose and evaluate distributed techniques relying on PCEs for the computation of interdomain constrained paths respecting the latter confidentiality requirement. (FSA 3)--UCL, 2006
Abstract
During the last years, MultiProtocol Label Switching (MPLS) has been deployed by most large Service Providers (SP). The main driver for MPLS deployment is the ability to provide [...]
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Toplu Taşıma Sistemleri Entegrasyonu Ve Şişli Mecidiyeköy Uygulaması
Y. Disli

Collection of open thesis in transport research (2006). Vol. 2006, 4

Abstract
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006
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Psychophysics study on conspicuity, aesthetics and urban environment harmony of traffic signs
A. Fontana

Collection of open thesis in transport research (2005). Vol. 2005, 4

Abstract
Neste trabalho são analisadas a conspicuidade (impacto visual), a estética e a harmonia com o meio ambiente dos principais sinais verticais de trânsito na área urbana. A análise é realizada com base nas respostas de questionários aplicados a grupos de pessoas (sujeitos), utilizando o método de comparação aos pares, da psicofísica. A pesquisa se concentrou nos seguintes sinais de regulamentação: sinal vertical de parada obrigatória, sinal vertical de sentido de circulação de via, sinal vertical de lombada, e no sinal de orientação de indicação de lugares. No caso dos sinais de regulamentação foram investigadas as seguintes características: tamanho da placa, largura do suporte e cor do suporte. No sinal de indicação de lugares, foram investigadas a cor do fundo da placa e a cor da estrutura de sustentação. No que concerne ao sinal de parada obrigatória, a pesquisa aponta como mais indicados uma largura da placa de 80 cm, suporte com largura de 12,5 cm e cor vermelha ou branca. Quanto ao sinal de sentido de circulação de via, as características mais indicadas são: largura da placa entre 60 e 70 cm, suporte com largura de 12,5 cm e cor vermelha. Em relação a placa de lombada, as características mais indicadas são: largura da placa de 80 cm, suporte com largura de 12,5 cm e cor preta. No que diz respeito de indicação de lugares, a pesquisa aponta como mais indicadas as seguintes características: cor da placa azul (distinta da cor verde regulamentada pelo Código de Trânsito Brasileiro) e suporte de sustentação da placa de cor verde (cor regulamentada pelo código do país) na cor preta ou verde. A comparação de alguns dos resultados encontrados no trabalho com aqueles obtidos em outras pesquisas mostram grande conformidade. Cabe ressaltar, contudo, que os resultados obtidos no trabalho devem ser vistos como tendências, pois o tamanho e a estratificação das amostras não satisfazem os requisitos para que os resultados tenham confiabilidade estatística. In this work the conspicuity (visual impact), aesthetic and the environment harmony of the main traffic signs in the urban area are analyzed. The analysis is performed based on questionnaires answers applyed the groups of people (subjects), using the psychophysics method of comparison in pairs. The research is focus in the following traffic signs: regulatory signs - stop sign, one way sign - , speed bump warning sign and guide signs. In the case of the regulatory and warning signs the next attributes had been investigated: size of the sign, width and color of the support. In guide sings, the ground color sign and structure color had been investigated. About stop sign, the research points as more indicated a sign width of 80 cm, support width of 12,5 cm and red or white color. Concerning on one way sign, the pointed out characteristics are: sign width between 60 and 70 cm, support width of 12,5 cm and red color. In relation the speed bump warning sign, the more indicated characteristics: sign width of 80 cm, support width of 12,5 cm and black color. About guide sings, the research indicates as more indicated the following featuress: blue color to the sign ground (distinct of the green sing regulated by the brazilian traffic code) and black or green color to sustentation structure of the green color sign (color regulated by country laws). The comparison of some results found in the work with those gotten in other early research shows a great conformity. Its important to highlightes, however, that the results gotten in the work must be seen as tendencies, because the sample size and stratification does not satisfy the requirements to the trustworthiness statistics results.
Abstract
Neste trabalho são analisadas a conspicuidade (impacto visual), a estética e a harmonia com o meio ambiente dos principais sinais verticais de trânsito na área urbana. [...]
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An eletronic system to support collective transport users.
D. Caetano

Collection of open thesis in transport research (2005). Vol. 2005, 2

Abstract
O principal objetivo deste trabalho foi o desenvolvimento de um sistema informatizado para o auxílio na escolha modal pelos usuários de transporte público. Neste sistema, as alternativas a considerar e soluções geradas devem se basear nas solicitações do usuário e poderão ser usadas para o planejamento tático e/ou estratégico do sistema de transporte considerado. O sistema foi modelado para solução através do algoritmo de fluxo em rede Label Correcting, capaz de lidar com esse problema multimodal, implementado em uma linguagem de programação orientada a objetos. O sistema foi concebido como uma aplicação de internet e, embora seja voltado para um sistema de transporte genérico, foi aplicado e testado com base nas alternativas de transporte disponíveis e malha de ruas da Cidade Universitária Armando de Salles Oliveira. The main target of this master of science research is the development of a tool to help on modal selection by the public transportation users, which will be implemented as an eletronic information system.Since the infomation must be provided in real time to the user,it is important to the system to be fast and easy to use.It is also a requirement that the system presents options and information to help the user on the selection of the best choice among all possible ones. The alternatives to be considered and generated solutions shall be based on the user requests related to origin and destination of the desired trip. The requests will be stored and could be used for tactic and/or strategic planning of the concerned system of transport. This multimodal problem will be modeled to be solved with the Label Correcting network flow algorithm and implemented using an object oriented language. Although addressed to a generic transport system,it will be implemented and tested based on the available transport alternatives and street mesh of the Cidade Universitaria Armando de Salles Oliveira. The system may be available to users through internet.
Abstract
O principal objetivo deste trabalho foi o desenvolvimento de um sistema informatizado para o auxílio na escolha modal pelos usuários de transporte público. Neste sistema, [...]
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Impacts to Dungeness Crab from the Southwest Washington Littoral Drift Restoration Project
N. Kohn, G. Williams, W. Pearson, J. Skalski

Collection of open reports in transport research (2005). Vol. 2005, 36

Abstract
The Benson Beach littoral drift restoration project is a demonstration project that will replenish sand on Benson Beach, the public beach north of the North Jetty at the mouth of the Columbia River (MCR), using material dredged from the river during normal maintenance dredging of the navigational channel. A U.S. Army Corps of Engineers (Corps) proposal involves pumping the material from a sump area on the south side of the jetty to Benson Beach using a cutter suction dredge, also known as a pipeline dredge. If this one-time demonstration project proves feasible and successful, up to a million cubic yards of sediment could be used to replenish the outer coast littoral drift system in successive years by the same process. The primary goal of this study was to assess the potential risk of impacts to Dungeness crab from the proposed Benson Beach littoral drift restoration process of using the cutter suction dredge to move sediment from the proposed sump area on one side of the North Jetty to the beach on the other side of the jetty. Because there are no direct measurements of crab entrainment by pipeline dredge operating outside of the lower Columbia River navigation channel, dredge impacts for the proposed demonstration project were estimated using a modification of the dredge impact model (DIM) of Armstrong et al. (1987). The model estimates adult equivalent loss (AEL) of crabs using crab population density from trawl surveys, dredge project information (gear type, season, location, volume), and an entrainment function relating crab population density to entrainment by the dredge. The input used in applying the DIM to the Benson Beach littoral drift restoration included the specific dredging scenario provided by the Corps, existing data on crab density in previously proposed sump areas, and a series of entrainment functions. A total of fourteen scenarios were modeled and the outcomes compared with six reference scenarios intended to represent realistic to worst cases. Dungeness crab entrainment and subsequent loss of recruitment to adult age classes and the crab fishery estimated for the Benson Beach littoral drift restoration project varied widely (over three orders of magnitude) because of the range of assumptions about initial crab density, dredging scenarios, and entrainment functions. Although the comparison to reference scenarios helps put the results in perspective, losses to the crab fishery could still span two orders of magnitude. This uncertainty can only be assessed by direct measurements of crab entrainment during the demonstration project if crab losses are to be more accurately estimated for the demonstration, which is recommended in order to evaluate cumulative crab losses from successive replenishment efforts.
Abstract
The Benson Beach littoral drift restoration project is a demonstration project that will replenish sand on Benson Beach, the public beach north of the North Jetty at the mouth [...]
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Air Traffic Management accident risk. Part 1: The limits of realistic modelling
P. Brooker

Collection of open reports in transport research (2005). Vol. 2005, 35

Abstract
The prime goal of the Air Traffic Management (ATM) system is to control accident risk. Some key questions are posed, including: What do design safety targets really mean and imply for risk modelling? In what circumstances can future accident risk really be modelled with sufficient precision? If risk cannot be estimated with precision, then how is safety to be assured with traffic growth and operational/technical changes? This paper endeavours to answer these questions by an analysis of the nature of accidents, causal factors and practical collision risk modelling. The main theme is how best to combine sound safety evidence and real world hazard analysis in a coherent and systematic framework.
Abstract
The prime goal of the Air Traffic Management (ATM) system is to control accident risk. Some key questions are posed, including: What do design safety targets really mean and [...]
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Air traffic management accident risk, part 2: repairing the deficiencies of ESARR4
P. Brooker

Collection of open reports in transport research (2005). Vol. 2005, 34

Abstract
This is a critique of ESARR4 and its main supporting documents. ESARR4 is the Eurocontrol Safety Regulatory Requirement Number 4 [Eurocontrol safety regulatory requirement ESARR4, Edition 1.0., Eurocontrol, Safety Regulation Commission, Brussels, 2001]: ‘Risk assessment and mitigation in ATM’, ATM standing for Air Traffic Management. It is demonstrated that ESARR4 and its supporting documents are defective. There is a lack of clarity about responsibilities for ATM safety. The claims ESARR4 etc. make for its proposed methodologies are overstated—not supported by sound evidence from real world hazard analysis. Serious negative effects from this defective document include mis-allocation of scarce safety resources and the diversion of attention away from real safety improvements—wasteful of regulators’ and managers’ time. Suggestions are made for repairing these deficiencies. The most important underlying change would be a refocusing on practical safety assessment based on methods that have already demonstrated their merits.
Abstract
This is a critique of ESARR4 and its main supporting documents. ESARR4 is the Eurocontrol Safety Regulatory Requirement Number 4 [Eurocontrol safety regulatory requirement [...]
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Technical Analysis of Hydrogen Production: Evaluation of H2 Mini-Grids
S. Lasher, J. Sinha

Collection of open reports in transport research (2005). Vol. 2005, 33

Abstract
We have assessed the transportation of hydrogen as a metal hydride slurry through pipelines over a short distance from a neighborhood hydrogen production facility to local points of use. The assessment was conducted in the context of a hydrogen "mini-grid" serving both vehicle fueling and stationary fuel cell power systems for local building heat and power. The concept was compared to a compressed gaseous hydrogen mini-grid option and to a stand-alone hydrogen fueling station. Based on our analysis results we have concluded that the metal hydride slurry concept has potential to provide significant reductions in overall energy use compared to liquid or chemical hydride delivery, but only modest reductions in overall energy use, hydrogen cost, and GHG emissions compared to a compressed gaseous hydrogen delivery. However, given the inherent (and perceived) safety and reasonable cost/efficiency of the metal hydride slurry systems, additional research and analysis is warranted. The concept could potentially overcome the public acceptance barrier associated with the perceptions about hydrogen delivery (including liquid hydrogen tanker trucks and high-pressure gaseous hydrogen pipelines or tube trailers) and facilitate the development of a near-term hydrogen infrastructure.
Abstract
We have assessed the transportation of hydrogen as a metal hydride slurry through pipelines over a short distance from a neighborhood hydrogen production facility to local [...]
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Technological Revolutions and Stock Prices
L. Pastor, P. Veronesi

Collection of open reports in transport research (2005). Vol. 2005, 32

Abstract
During technological revolutions, stock prices of innovative firms tend to exhibit high volatility and bubble-like patterns, which are often attributed to investor irrationality. We develop a general equilibrium model that rationalizes the observed price patterns. The high volatility results from high uncertainty about the average productivity of a new technology. Investors learn about this productivity before deciding whether to adopt the technology on a large scale. For technologies that are ultimately adopted, the nature of uncertainty changes from idiosyncratic to systematic as the adoption becomes more likely; as a result, stock prices fall after an initial run-up. This 'bubble' in stock prices is observable ex post but unpredictable ex ante, and it is most pronounced for technologies characterized by high uncertainty and fast adoption. We examine stock prices in the early days of American railroads, and find evidence consistent with a large-scale adoption of the railroad technology by the late 1850s.
Abstract
During technological revolutions, stock prices of innovative firms tend to exhibit high volatility and bubble-like patterns, which are often attributed to investor irrationality. [...]
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Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes
L. Wang, S. Mattigod, I. Aksay, A. Felmy, D. Hobbs, D. Dabbs

Collection of open reports in transport research (2005). Vol. 2005, 31

Abstract
uminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations.
Abstract
uminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level [...]
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