Headway Time and Crashes Among Novice Teens and Experienced Adult Drivers in a Simulated Lead Truck Braking Scenario

Driving simulators can be used to evaluate driving performance under controlled, safe conditions. Teen drivers are at particular risk for motor vehicle crashes and simulated driving can provide important information on performance. We developed a new simulator protocol, the Simulated Driving Assessment (SDA), with the goal of providing a new tool for driver assessment and a common outcome measure for evaluation of training programs. As an initial effort to examine the validity of the SDA to differentiate performance according to experience, this analysis compared driving behaviors and crashes between novice teens (n=20) and experienced adults (n=17) on a high fidelity simulator for one common crash scenario, a rear-end crash. We examined headway time and crashes during a lead truck with sudden braking event in our SDA. We found that 35% of the novice teens crashed and none of the experienced adults crashed in this lead truck braking event; 50% of the teens versus 25% of the adults had a headway time time \u3c 3 seconds at the time of truck braking. Among the 10 teens with \u3c 3 seconds headway time , 70% crashed. Among all participants with a headway time of 2-3 seconds, further investigation revealed descriptive differences in throttle position and brake pedal force when comparing teens who crashed, teens who did not crash and adults (none of whom crashed). Even with a relatively small sample, we found statistically significant differences in headway time for adults and teens, providing preliminary construct validation for our new SDA

On robustness against JPEG2000: a performance evaluation of wavelet-based watermarking techniques

With the emergence of new scalable coding standards, such as JPEG2000, multimedia is stored as scalable coded bit streams that may be adapted to cater network, device and usage preferences in multimedia usage chains providing universal multimedia access. These adaptations include quality, resolution, frame rate and region of interest scalability and achieved by discarding least significant parts of the bit stream according to the scalability criteria. Such content adaptations may also affect the content protection data, such as watermarks, hidden in the original content. Many wavelet-based robust watermarking techniques robust to such JPEG2000 compression attacks are proposed in the literature. In this paper, we have categorized and evaluated the robustness of such wavelet-based image watermarking techniques against JPEG2000 compression, in terms of algorithmic choices, wavelet kernel selection, subband selection, or watermark selection using a new modular framework. As most of the algorithms use a different set of parametric combination, this analysis is particularly useful to understand the effect of various parameters on the robustness under a common platform and helpful to design any such new algorithm. The analysis also considers the imperceptibility performance of the watermark embedding, as robustness and imperceptibility are two main watermarking properties, complementary to each other

Adsorption of 1,1,1,2-Tetrafluoroethane on Activated Charcoal

This paper presents adsorption isotherms for HFC-134a on activated charcoal, in the temperature range of 273-353 K and for pressures up to 0.65 MPa, measured using the volumetric method. Three samples of charcoals with widely varying surface areas were chosen. The shapes of the isotherms,obtained from the experimental data were similar in all cases and comparable to those reported in the literature. Adsorption parameters were evaluated from the isotherms using the Dubinin-Astakhov (DA) equation. The concentration dependence of the isosteric enthalpies of adsorption is extracted from the data

Influence of cycle time and collector area on solar driven adsorption chillers

Dynamic performance of a single-stage, two-bed, silica gel + water adsorption chiller operating in Bangalore, India is studied. Driving thermal energy is provided directly by an evacuated tube solar collector field. System dynamics are evaluated in the absence of thermal storage, which causes intra-day fluctuations in heat source and evaporator temperatures, which in turn influence the system performance. These dynamics are demonstrated for representative days in the months of April (summer) and December (winter). The focus is on the effect of variation of the collector area and the adsorption cycle time on the system performance. The maximum temperature of heat transfer fluid (water) is limited to 95 degrees C. The cyclic and daily averages of solar coefficient of performance (DACOPsoi) and cooling capacity (DACC) are used as key performance indicators. One of the key aspects of the this study is to show that both of them can be maximized by suitably choosing the collector area and cycle time. Further, it is demonstrated that the solar driven adsorption chiller described here is ideally suited for cascading with an air-cooled R-134a vapour compression refrigeration system (VCRS). The variable throughput obtained from the solar adsorption chiller can help in liquid sub-cooling and hence to cover the deficit in cooling capacity of the VCRS arising due to high ambient temperature. (C) 2016 Elsevier Ltd. All rights reserved

Demographic Center, and Mr. Mark Filipi, Metropolitan Council for helping me by

I would like to thank my advisor, Dr. David Levinson for his invaluable guidance and assistance during the entire course of my graduate study. I would like to thank Mr. Mark Filipi, Metropolitan Council and Dr. David Anderson, University of Minnesota for providing the data required for the analysis. I also would like to thank Mr. Charles Delisi, MnDOT for providing data required for this study. I would also like to thank the State Demographic Center for providing the data used for important analysis as part of this work. I would also thank Ms. Gail Carson, Stat