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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Wayfinding in a City Environment: Driver Experience and Strategies

King, Katherine 15 August 2014 (has links)
The following study aimed to understand pure wayfinding search strategies and identify the most efficient strategy when discovering a new environment. Participants performed one drive in a simulated city environment within a driving simulation lab. Their objective was to locate a target within the city, without any navigational aids (maps, GPS, etc.). Efficiency measures, such as number of road segments covered between origin and target, were evaluated. Experience and gender were also analyzed. There was a significant difference of efficiency between search strategies. Experience did not impact a driver’s efficiency. The knowledge from this study can be used in city planning of high tourist areas or major facilities.
42

An experimental study of driver fatigue: subjective driver fatigue score, driving performance, and driver fatigue countermeasures

LIU, Shixu 05 1900 (has links)
Two experiments were conducted to study driver fatigue. The first investigated driver fatigue and driving performance. Thirty one Participants completed a questionnaire to obtain their Subjective Driver Fatigue Score (SDFS) quantifying fatigue levels. Driving performance was evaluated by measuring steering wheel, lateral position, etc. The results showed significant increases in the SDFS and driving performance impairment following simulated driving sessions. Further analysis suggested a linear relationship between the SDFS and the standard deviation of lateral acceleration. Subjective fatigue assessment and driving performance were plotted as radar diagrams to show the multidimensional characteristics. The second experiment examined effects of caffeine and music on the SDFS, driving performance, and 8 EEG signal parameters. Initially, there was no significant inter-sessional variation in the dependent variables, suggesting all sessions were started at similar states. The final SDFS for caffeine and music sessions were significantly lower than control sessions, suggesting both inhibited subjective fatigue increase. Driving performance deteriorated less significantly in caffeine sessions than in control and music sessions. The results suggested that caffeine was more effective than music. EEG was not changed significantly. However, the amplitude of α wave increased significantly for an extremely fatigued individual, along with vehicle drifting and micro-sleep. In conclusion, the SDFS developed in this study successfully estimated subjective driver fatigue levels and showed a linear relationship with driving performance during driving tasks. Caffeine and music reduced driver fatigue subjectively similarly, but caffeine also helped subjects maintain driving performance. / Thesis / Doctor of Philosophy (PhD) / In this project, two experiments were conducted to study driver fatigue. A subjective driver fatigue score was specially developed and used as a driver fatigue indicator. This score was sensitive to driver fatigue changes, and showed a linear relationship with the standard deviation of lateral acceleration. Two popular driver fatigue countermeasures, caffeine and music, were examined to investigate the effects on subjective driver fatigue and driving performance. The results showed that caffeine reduced subjective driver fatigue and helped driver maintain good driving performance; however, music only helped drivers reduce subjective driver fatigue.
43

Examining the impact a bus driver attendance incentive program had on bus driver attendance in a rural Mississippi school district

Allison, Samuel B. 08 December 2023 (has links) (PDF)
This study examines the impact of a bus driver attendance incentive program implemented in a rural Mississippi school district with the aim of improving bus driver attendance rates. There is a shortage of bus drivers across Mississippi which has made bus driver attendance paramount. Bus driver absenteeism causes disruptions in student transportation services and affects overall school operations. To address this problem, a rural Mississippi school district introduced a bus driver attendance incentive program that provided financial incentives for bus drivers who maintained perfect attendance rates each month. The research methodology involved collecting and analyzing attendance data for bus drivers over a period of 2 academic years: 1 year prior to the COVID-19 Pandemic and before the implementation of the incentive program and the other 1 year after the introduction of the incentive plan. Although the findings did not reveal a significant positive impact on bus driver attendance between the 2 years in the study, the data did show a number of drivers benefited from the incentive program.
44

AN ELECTROLYTIC CAPACITOR-LESS APPROACH TO ELIMINATING FLICKER IN LED LIGHTING

Kavouras, Alex M., Sr. 02 May 2016 (has links)
No description available.
45

An Examination of Driver Performance Under Reduced Visibility Conditions When Using An In-Vehicle Signing Information System (ISIS)

Collins, Dennis James 10 April 1997 (has links)
Recent technological innovations and the need for increased safety on the world's roads have led to the introduction of In- Vehicle Information Systems (IVIS). These systems will provide navigation and advisory information to drivers while they are driving. One aspect of these systems, In-vehicle Signing Information Systems (ISIS), would provide the warning, regulatory, and advisory information that is currently found on road signs. These systems may be of particular benefit when external elements such as rain, snow, or night driving reduce or eliminate the opportunity for drivers to detect road signs. This study attempts to determine what benefits, if any, are realized by drivers using this system. Fifty-eight drivers operated an instrumented Oldsmobile Aurora under eight conditions. The eight conditions consisted of a daylight-clear weather-ISIS condition, a daylight-clear weather-No ISIS condition, a daylight-rain-ISIS condition, a daylight-rain-No ISIS condition, a night-clear weather-ISIS condition, a night-clear weather-No ISIS condition, a night-rain-ISIS condition, and a night-rain-No ISIS condition. Younger drivers (18-30 years old) and older drivers (65 years or older) took part in this study. Three measures of driver performance were collected along with subjective preference data. Each measure was evaluated in order to determine what impact, if any, weather, time of day, age, and ISIS use had on performance. Subjective data was evaluated to determine driver preference and acceptance of the ISIS display. The results indicated that use of the ISIS display led to reduced speeds and greater reaction distances for all drivers. Evidence was found that seems to indicate that older drivers may receive a greater benefit in complex, unfamiliar, or low visibility situations. Evidence was also found that indicates that all drivers may receive a greater benefit at night for the complex or unfamiliar situations. Subjectively, the majority of the drivers indicated that the ISIS display made them more aware of road sign information. / Master of Science
46

Topologies and Modelings of Novel Bipolar Gate Driver Techniques for Next-Generation High Frequency Voltage Regulators

FU, Jizhen 30 July 2010 (has links)
As is predicted by Moore’s law, the transistors in microprocessors increase dramatically. In order to increase the power density of the microprocessors, the switching frequency of the Voltage Regulator (VR) is expected to increase to MHz level. However, the frequency dependent loss will increase proportionally. In order to meet requirements of the next-generation microprocessors, three new ideas are proposed in this thesis. The first contribution is a new bipolar Current Source Driver (CSD) for high frequency power MOSFET. The proposed CSD alleviates the gate current diversion problem of the existing CSDs by clamping the gate voltage to a flexible negative value during turn off transition. Therefore, the proposed driver turns off the MOSFET much faster. For buck converters with 12 V input at 1MHz switching frequency, the proposed driver improves the efficiency from 80.5% using the existing CSD to 82.5% at 1.2V/30A, and at 1.3V/30A output, from 82.5% to 83.9%. The second contribution is an accurate analytical loss model of a power MOSFET with a CSD. The current diversion problem that commonly exists in CSDs is investigated mathematically. The inductor value of the CSD is optimized to achieve minimum loss for the synchronous buck converter. The experimentally measured loss matches the calculated loss very well. The efficiency with the optimal CSD inductor is improved from 86.1% to 87.6% at 12V input, 1.3V/20A output in 1MHz switching frequency and from 82.4% to 84.0% at 1.3V/30A output. The third contribution is a new inductorless bipolar gate driver for control FET of buck converters. The most important advantage of the driver presented in this thesis is that it can turn off the power MOSFETs with a negative voltage, which will significantly reduce the turn off time and thus switching loss. In addition, the proposed bipolar gate driver has no inductor in the driver circuit; therefore it can be fully integrated into a chip. For buck converter with 5V input, 1.3V/25A load, in 2 MHz frequency, the proposed gate driver increases the efficiency from 75.8% to 77.8% and from 72.9% to 76.5% at 5V input, 1.3V/25A load, in 2.5 MHz switching frequency. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-07-30 14:06:04.003
47

Driver Acceptance of Advanced Driver Assistance Systems and Semi-Autonomous Driving Systems

Rahman, Md Mahmudur Mahmudur 12 August 2016 (has links)
Advanced Driver Assistance Systems (ADAS) and semi-autonomous driving systems are intended to enhance driver performance and improve transportation safety. The potential benefits of these technologies, such as reduction in number of crashes, enhancing driver comfort or convenience, decreasing environmental impact, etc., are well accepted and endorsed by transportation safety researchers and federal transportation agencies. Even though these systems afford safety advantages, they challenge the traditional role of drivers in operating vehicles. Driver acceptance, therefore, is essential for the implementation of ADAS and semi-autonomous driving systems into the transportation system. These technologies will not achieve their potential if drivers do not accept them and use them in a sustainable and appropriate manner. The potential benefits of these in-vehicle assistive systems presents a strong need for research. A comprehensive review of current literature on the definitions of acceptance, acceptance modelling approaches, and assessment techniques was carried out to explore and summarize the different approaches adopted by previous researchers. The review identified three major research needs: a comprehensive evaluation of general technology acceptance models in the context of ADAS, development of an acceptance model specifically for ADAS and similar technologies, and development of an acceptance assessment questionnaire. Two studies were conducted to address these needs. In the first study, data collection was done using two approaches: a driving simulator approach and an online survey approach. In both approaches, participants were exposed to an ADAS and, based on their experience, responded to several survey questions to indicate their attitude toward using the ADAS and their perception of its usefulness, usability, reliability, etc. The results of the first study showed the utility of the general technology acceptance theories to model driver acceptance. A Unified Model of Driver Acceptance (UMDA) and two versions (a long version with 21 items and a short version with 13 items) of an acceptance assessment questionnaire were also developed, based on the results of the first study. The second was conducted to validate the findings of first study. The results of the second study found statistical evidence validating UMDA and the two versions of the acceptance assessment questionnaire.
48

ROADSkills: Developing an evidence-based and user-informed approach to refreshing older adults' driving skills / Refreshing older adults' driving skills

Sangrar, Ruheena January 2020 (has links)
Driving is the preferred mode of transportation among community-dwelling older Canadians. Unfortunately, drivers aged 70+ have a high risk of being injured or killed in a collision. Many collisions are caused by poor driving habits, which could be avoided by improving their behind-the-wheel behaviours. The manuscripts in this thesis describe the development of an evidence-based and user-informed driver training program aimed at refreshing older adults’ driving skills. First, a systematic review of older driver training programs was undertaken to examine evidence specific to the impact of this training on improving road safety knowledge, self-perceived driving abilities, and on-road performance. Results highlighted the breadth of approaches used to train older drivers. Interventions were most effective when feedback was tailored to the specific needs of an aging driver. The second manuscript outlines a qualitative descriptive analysis exploring older adults’ motivations to participate in driver training with key stakeholders (i.e., older drivers and service delivery providers). Findings indicated having insight into one’s driving abilities, experiencing a near-miss or crash, as well as an openness to improving behind-the-wheel skills were factors that could influence seeking out and participating in such training. Stakeholders also emphasized considerations for educating older drivers. The final manuscript describes the design and evaluation of a driver training program. In this randomized controlled trial, older drivers watched either a video of tailored feedback on their driving or a generic video on aging-in-place. When the on-road performance was compared between treatment groups, those who received tailored feedback significantly reduced the number of errors they made behind-the-wheel. Ensuring driver training programs are designed to consider the specific needs and preferences of older adults is critical, which can lead to innovations that help maintain driving ability and community mobility in later life. / Thesis / Doctor of Philosophy (PhD) / Being able to drive is important to many older Canadians. Unfortunately, drivers aged 70+ have a high risk of being injured or killed in a car crash. Many crashes could be avoided by improving their driving skills. This thesis describes the development of an older driver training program. The first study examined research evidence on such programs where tailoring feedback was key to improving on-road performance. In the second study, older adults and other stakeholders identified what was important when designing training for aging drivers. They felt the focus should be on areas of improvement as well as strengths when behind-the-wheel. In the final study, older drivers underwent training where they watched either a video with feedback on their driving or a generic video on aging-in-place. Those who received feedback made fewer mistakes behind-the-wheel. Findings emphasize the importance of including older adults’ needs and preferences when designing driver training programs.
49

Driver Management for Less-than-Truckload Carriers

Karacik, Burak 02 January 2007 (has links)
The trucking industry is vitally important to the economy, providing an essential service by transporting goods between businesses and consumers. The less-than-truckload (LTL) industry is an important segment, serving businesses that ship quantities between 150 lbs and 10,000 lbs. Large LTL carriers use thousands of drivers to move loads between terminals in their network, and each driver may be used for multiple dispatches between rest periods. Driver wages are a major component of transportation costs. Consequently, cost-effective driver management is of crucial importance for the profitability of LTL carriers. This thesis investigates a variety of issues related to driver management. In this thesis, we describe a dynamic driver scheduling scheme developed for a large U.S. LTL carrier. Dynamic driver scheduling is challenging because drivers must abide by a complex set of rules, including government and union regulations, and trucking moves are not pre-scheduled. The technology developed combines greedy search with enumeration of time-feasible driver duties, and is capable of generating cost-effective schedules covering 15,000 20,000 loads in minutes. One of the key tactical questions faced by an LTL carrier is how many drivers to locate at each terminal. Unionized carriers have bid drivers that can only move loads between their domicile and a designated region. The developed allocation technology determines the number of drivers to allocate to each terminal as well as the designated region for bid drivers. Computational experiments based on real-life dispatch data demonstrate the effectiveness of our domiciling methodology, and show that union rules may result in substantially larger driver fleets, in some cases up to 50% larger. Finally, we investigate a fundamental question related to driver management in order to obtain some fundamental insights: determining the minimum number of drivers required to cover a set of loaded moves. The problem is shown to be polynomially solvable without any restrictions on driver schedules. For variants with restrictions, several easily computable lower bounds are derived, integer programming formulations are presented, and fast heuristics are designed and analyzed. A computational study provides insights into the quality of the lower bounds and heuristic solutions.
50

DRIVING SIMULATION AND REACTION TIME INVESTIGATION ON DRIVER FOOTEDNESS

Ali, Ahmed M. 29 August 2019 (has links)
No description available.

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