Abstract

The calibration of paleoclimate proxies is one of the key problems in the study of paleoclimate at present. Historical documentary records of climate are suitable for calibration on dating and the climatic implication of the proxy data in a climatological sense. A test calibration on correcting the Delingha tree ring precipitation series using Chinese historical documentary records shows that among the 44 extreme dry cases in 1401–1950 AD, 42 cases (or 95.5%) are believable. Thus the long series of Delingha rings-denoted precipitation is highly reliable. Another test to validate the monsoon intensity proxy data based on the Zhanjiang Huguangyan sediments using historical records indicates that the years of Lake Maar Ti content series-designated winter monsoon intensities are entirely opposite to historical documents-depicted years of harsh winters in 800–900 AD. As a result, serious doubt is raised about the climatic implication of this paleo-monsoon proxy series. Zhang, D., 2011: Test calibration of the paleoclimatic proxy data with Chinese historical records. Adv. Clim. Change Res., 2 (1), doi: 10.3724/SP.J.1248.2011.00038.

Abstract

The limited funding available for roadway capacity expansion and the growing funding gap, in conjunction with the increasing congestion, creates a critical need for innovative lane use management options for Indiana. Various cost-effective lane use management strategies have been implemented in the U.S. and worldwide to address these challenges. However, all the strategies have their own costs, operational characteristics, and additional requirements for field deployment. Hence there is a need for systematic simulation-based methodology to perform a comprehensive study to identify congested corridors and the specific set of lane use management strategies that are effective in Indiana. A systematic simulation-based methodology is proposed for evaluating lane use management strategies. A 10-mile stretch of the I-65 corridor south of downtown Indianapolis was selected as the study corridor using traffic analysis. The demand volumes for the study area were determined using subarea analysis. Its performance was evaluated using a microsimulation-based analysis in the context of alleviating congestion for three strategies: reversible lanes, high occupancy vehicle (HOV) lanes and ramp metering. Furthermore, an economic evaluation of these strategies was performed to determine the financial feasibility of their implementation. Results from this analysis indicated that reversible lanes and the ramp metering strategies improved traffic conditions on the freeway in the major flow direction. Implementation of the HOV lane strategy resulted in improved traffic flow conditions on the HOV lanes but aggravated congestion on the general purpose (GP) lanes. The HOV lane strategy was found to be economically infeasible due to low HOV volume on these lanes. The reversible lane and ramp metering strategies were found to be economically feasible with positive net present values (NPV), with the NPV for the reversible lane strategy being the highest.

Abstract

Engines for A/B/C class vehicles place high emphasis on economic viability. Thus, many innovations focus on"br" optimum system integration of cost effective technologies, which are individually optimized and controlled within"br" the interrelations of engine, exhaust gas aftertreatment system and vehicle. The European project REWARD"br" conducted such a comprehensive approach with a 1.6 liter diesel engine for a small SUV class vehicle. The core"br" of this development is a new combustion concept which is combined with a specifically tailored aftertreatment"br" system. The goal is the demonstration of an increased fuel economy and a reduction of emissions significantly"br" below the Euro 6 limits under real driving conditions. These targets are demonstrated with a vehicle emphasizing"br" that the improvements refer exclusively to the new engine and aftertreatment system development."br" The approach focuses on conventional combustion parameters such as the optimum design matching of new"br" combustion bowls with advanced fuel injectors, injection characteristics and a reduced in-cylinder charge motion"br" (swirl). Outside of these core features further parameters refer to high-pressure/ low-pressure EGR and the"br" charging system. The target is to minimize engine-out emissions and to provide specific exhaust characteristics"br" which are optimum matched to particular aftertreatment system concepts."br" Various aftertreatment concepts have been systematically evaluated in view of their performance, reliability and"br" economy. Initially, NOx reduction with a single NOx Storage Catalyst (NSC) was considered. However, even if"br" combined with the low engine-out NOx solution, this initial approach requires excessive NSC purging at elevated"br" exhaust temperatures, which severely deteriorates the fuel economy. Thus, NSC has been completely omitted and"br" replaced by Selective Catalytic Reduction (SCR) with economically “active” urea dosing. Due to a sophisticated"br" temperature management system low temperature operation can be bridged by a diesel Cold Start Concept"br" (dCSCTM) catalyst. The paper describes the comprehensive approach and presents some projected results.

Abstract

Geotechnical in-situ test methods provide valuable data for asset development, operation, and decommissioning. For confidence in test results, industry typically requires calibration and verification of in-situ test sensors to be conducted in a calibration laboratory. A calibration laboratory typically operates according to ISO/IEC 17025 (2017) ‘general requirements for the competence of testing and calibration laboratories’, or similar standard. This paper summarises observations from practice, with focus on the following challenges (1) evaluation of measurement uncertainty of key parameter values for which no standardised methods or verification materials are available, (2) validation of test methods with no backup from a formal standard published by a standardisation organisation and (3) field test site and interlaboratory comparisons within a competitive industry setting. Specific examples are presented for the (1) estimation of calibration uncertainty for sleeve friction of a subtraction-type cone penetrometer and (2) method validation for thermal conductivity of soil derived from in-situ heat flow measurements.

Abstract

The two authors’ company (IGS) is an in situ testing and sampling contractor. Approximately 40% of the company’s business is cone penetration testing (CPT). The CPT cones they use are good quality commercial units supplied by the Dutch company Geomil, with qc capacities ranging from 3MPa to 100MPa. Both compression-type and subtraction-type cones are used. IGS undertakes their own in-house calibrations on all cones, using externally calibrated load cells, and a combination of dead weights and hydraulic load application. Calibration and adjustment is undertaken on every cone on an unusually frequent basis, explained in the paper, far more frequently than current standards or manufacturer recommendations require. At each calibration, the reference readings (sometimes known as baseline readings) of each cone’s tip qc, sleeve fs, and pore pressure U sensors are noted. And the slope of the applied-load/pressure-vs-cone-readout for each of these sensors (ie accuracy) is measured and adjusted to give as close as reasonably possible 100% accurate output. All of this is recorded for each cone. Thus the authors have a database of reference reading drift that can be compared to slope adjustments (ie calibration adjustments) that have been needed to achieve the desired cone accuracy. This paper graphically reports the data for tip and sleeve of eight typical CPT cones of the day-to-day types used by the company.

Abstract

Even the most experienced geotechnical engineer is likely to assume that the results of cone penetration tests are unquestionably accurate, reliable and repeatable. There are, however, multiple factors, some that have nothing to do with the soil properties, that need to be carefully addressed prior to testing if the equipment is to return results that can be relied on for design purposes. In soils which are very soft or soft, cone penetration test results can be particularly sensitive to the method of calibration. A high degree of rigour to the calibration process is required, otherwise there is a risk that the results obtained could be inaccurate and adversely impact on the reliability of the interpretation of design soil strength profiles. In this technical note sources of error in cone calibration are discussed. Reference is made to ISO 22476-1 which was revised in 2022, with the addition of a defined approach to calibration. Examples are used to demonstrate the typical errors that could be introduced during calibration.

Abstract

Despite substantive growth in utilization of positron emission tomography (PET) myocardial perfusion imaging (MPI), evidence on its prognostic value is limited. We aimed to comprehensively evaluate the prognostic literature of PET perfusion measures according to the most recent American Heart Association recommendations for assessment of novel cardiovascular biomarkers. We searched the literature for studies reporting associations of PET MPI measures and outcomes in patients with known or suspected coronary artery disease. We documented hazard ratios (HR) and 95% confidence intervals (CI) of association effects and quantitatively synthesized them with random-effects meta-analyses. Discrimination, calibration and risk reclassification after addition of PET MPI measures to standard prognostic models were documented. We identified 20 eligible studies with median n = 551 patients. In meta-analyses, the extents of ischemic and scarred myocardium were significantly associated with cardiac death. Meta-analyses of multivariate estimates for abnormal summed stress score ≥ 4 and myocardial perfusion reserve < 2 revealed significant associations with major adverse cardiovascular events [HR (95% CI) 2.30 (1.53–3.44) and 2.11 (1.33–3.36), respectively]. Changes in model discrimination, calibration or risk reclassification were reported in 5 studies (8 prognostic evaluations). There were marginal improvements in discrimination based on C index and no improvements in model calibration. Net reclassification index ranged from 9.8% to 14.2% and risk classification was significantly improved in 4/5 prognostic evaluations. PET MPI measures were strongly associated with adverse patient outcomes. Risk classification was more consistently improved than discrimination and calibration after addition of PET MPI measures, but reporting of such metrics was overall limited.

Abstract

This paper describes a system for pedestrian detection in infrared images implemented and tested on an experimental vehicle. A specific stabilization procedure is applied after image acquisition and before processing to cope with vehicle movements affecting the camera calibration. The localization of pedestrians is based on the search for warm symmetrical objects with specific size and aspect ratio. A set of filters is used to reduce false detections. The final validation process relies on the human shape’s morphological characteristics. Document type: Part of book or chapter of book

Abstract

:This paper presents an autocalibration method to determine the pose of a stereo vision system based on knowing the geometry of the ground in front of the cameras. This pose changes considerably while the vehicle is driven, therefore it is good to know constantly the pose of the camera for several applications based on computer vision, such as advanced driver assistance systems, autonomous vehicles or robotics. These constant changes of the pose make interesting to be able to detect constantly the variations in its extrinsic parameters (height, pitch, roll). The validation of the autocalibration method is accomplished by a visual odometry implementation. A study of the improvement of the results of the visual odometry estimation taking into account the changes of the camera pose is presented, demonstrating the advantages of the autocalibration method. This work was also supported by Spanish Government through the CICYT projects FEDORA (Grant TRA2010-20255-C03-01) and Driver Distraction Detector System (Grant TRA2011-29454-C03-02).