Thesis (Ph. D. in Civil Engineering)--University of California, Berkeley, 2006. / Cover title. "Fall 2006." Includes bibliographical references (leaves 292-300). Also available online.

published_or_final_version / Education / Master / Master of Education

The thermodynamic equation of seawater - 2010 (TEOS-10) is hampered by the inability to measure absolute salinity or density in situ. No new advances for in situ salinity or density measurement have taken place since the adoption of the practical salinity scale in 1978. In this thesis three possible technologies for in situ measurements are developed and assessed: phased conductivity, an in situ density sensor and sound speed sensors. Of these, only sound speed sensors showed the potential for an in situ TEOS-10 measurement solution. To be implemented, sensor response times need to be matched and the sound speed sensor accuracy must be improved. Sound speed sensor accuracy is primarily limited by the calibration reference, pure water. Test results indicate the TEOS-10 sound speed coefficients may also need to be improved. A calibration system to improve sound speed sensor accuracy and verify the TEOS-10 coefficients is discussed. / Graduate / 0415 / 0986 / TDakin@UVic.ca

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Safety in highway work zones has become a concern among Departments of Transportation (DOTs) throughout the country as the highway network has begun to age and more maintenance and construction work has been necessary. Safety in highway work zones is more compromised than in other areas for two reasons. First, the construction workers are near traveling vehicles as they perform their already dangerous work, increasing the risk of an accident. Second, the highway user is at increased risk because of the increase in roadside obstacles, because other vehicles are more likely to act in unpredictable ways (such as sudden braking or lane changes), and because vehicles are more likely to be traveling closer together (due to decreased capacity). Researchers are looking at several mechanisms for improving safety in highway work zones, including lowering the mean speed of vehicles in the work zone, encouraging drivers to be alert in work zones, improving the control of traffic in merging areas, and improving the safety devices that separate vehicles and construction workers. This study focuses on the goal of reducing speed in work zones. First, methods of speed reduction used by state DOTs throughout the country are identified, and the research surrounding them is summarized. Next, the methodology and results of a field study that tests the efficacy of the Speed Monitoring Display (SMD) are described in detail. Finally, the results of a survey that was conducted to ascertain drivers' opinions of the SMD are presented. For the field study, three main conditions were analyzed: a no-treatment case, with the MUTCD signs and barriers; a treatment case using the SMD; and a treatment case using a police vehicle. In the no-treatment case, average vehicle speed was reduced about 3 mph as vehicles entered the work area of the work zone. With the SMD, average vehicle speed was reduced an additional 4 mph. With the police vehicle, average vehicle speed was reduced about 6 mph more than in the no-treatment case. Thus, average vehicle speed was reduced in all treatment cases; however, the police vehicle was slightly more effective than the SMD at reducing average speeds. (These conclusions are valid at a 95 percent confidence level.) The results of the survey also suggest that the SMD is a promising option for state DOTs. According to drivers' self-reports, those who normally drive a little faster than the speed limit are likely to slow down in reaction to an SMD, but drivers who normally ignore the speed limit are likely to ignore an SMD. The majority of drivers surveyed had positive reactions to SMDs, reporting that they feel SMDs are accurate, not distracting, and not difficult to read.

Reduced-speed school zones greatly improve the safety of young children commuting to and from school and provide larger gaps in traffic for children to cross the street. The main focus of this study was to determine effective methods for increasing speed compliance in reduced-speed school zones. This objective was accomplished through an in-depth literature review, a public opinion survey of Utah drivers, and an evaluation of the effects of speed monitoring displays (SMDs) in school zones. The main focus of the literature review was to determine how to increase and maintain speed limit compliance within school zones. Information about the following topics with respect to school zones was researched and compiled: traffic control devices, SMDs, law enforcement, and other speed influences. A public survey was developed and implemented to evaluate the feelings and concerns of Utah drivers with respect to school-zone safety and school-zone traffic control devices. The survey was conducted in various locations throughout the state of Utah and proved to be an effective tool. The majority of those surveyed felt there was a need to improve school-zone safety in Utah. An evaluation of SMDs in four school zones throughout the state was performed. The results concluded that the SMDs analyzed in this study proved to increase speed compliance in most cases. In some cases, the SMDs maintained their effectiveness at increasing speed compliance over time; on the other hand, others lost some of their effectiveness over time, possibly due to higher percentages of commuter traffic. For the most part, speed compliance increased as manifested by the decrease in mean speed, standard deviation, 10 mph pace range, and the percentage of vehicles exceeding the 20 mph school-zone speed limit. In summary, the results of this study suggest that a combination of effective traffic control devices, public education, and appropriate law enforcement are all necessary to improve speed-limit compliance in school zones.

Background: Physical functioning and mobility of older populations are of increasing interest when populations are aging. Lower body functioning such as walking is a fundamental part of many actions in daily life. Limitations in mobility threaten independent living as well as quality of life in old age. In this study we examine differences in physical aging and convert those differences into the everyday measure of single years of age. Methods: We use the English Longitudinal Study of Ageing, which was collected biennially between 2002 and 2012. Data on physical performance, health as well as information on economics and demographics of participants were collected. Lower body performance was assessed with two timed walks at normal pace each of 8 ft (2.4 m) of survey participants aged at least 60 years. We employed growth curve models to study differences in physical aging and followed the characteristic-based age approach to illustrate those differences in single years of age. Results: First, we examined walking speed of about 11,700 English individuals, and identified differences in aging trajectories by sex and other characteristics (e.g. education, occupation, regional wealth). Interestingly, higher educated and non-manual workers outperformed their counterparts for both men and women. Moreover, we transformed the differences between subpopulations into single years of age to demonstrate the magnitude of those gaps, which appear particularly high at early older ages. Conclusions: This paper expands research on aging and physical performance. In conclusion, higher education provides an advantage in walking of up to 15 years for men and 10 years for women. Thus, enhancements in higher education have the potential to ensure better mobility and independent living in old age for a longer period. (author's Abstract)

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / The deployment of network-based airborne instrumentation systems is leading to cost-efficient replacement of legacy instrumentation systems. One application of airborne data acquisition that has been developed and maintained separately from traditional avionics and orange-wire data acquisition systems is high-speed camera packages. The development of network-based instrumentation systems has led to an opportunity to unify these two previously distinct airborne data acquisition activities. This paper describes the range-video network-based instrumentation system (rNET) being implemented by the 46th Test Wing, 846th Test Support Squadron at Eglin Air Force Base, FL to replace the existing Airborne Separation Video System (ASVS).

Wind is a fluctuating source of energy and, therefore, it can cause several technical impacts. These can be tackled by forecasting wind speed and thus wind power. The introduction of several statistical models in this field of research has brought to light promising results for improving wind speed predictions. However, there is not converging evidence on which is the optimal method. Over the last three decades, significant research has been carried out in the field of short-term forecasting using statistical models though less work focuses on longer timescales. The first part of this work concentrated on long-term wind speed variability over the UK. Two subsets have been used for assessing the variability of wind speed in the UK on both temporal and spatial coverage over a period representative of the expected lifespan of a wind farm. Two wind indices are presented with a calculated standard deviation of 4% . This value reveals that such changes in the average UK wind power capacity factor is equal to 7%. A parallel line of the research reported herein aimed to develop a novel statistical forecasting model for generating monthly mean wind speed predictions. It utilised long-term historic wind speed records from surface stations as well as reanalysis data. The methodology employed a SARIMAX model that incorporated monthly autocorrelation of wind speed and seasonality, and also included exogenous inputs. Four different cases were examined, each of which incorporated different independent variables. The results disclosed a strong association between the independent variables and wind speed showing correlations up to 0.72. Depending on each case, this relationship occurred from 4- up to 12-month lags. The inter comparison revealed an improvement in the forecasting accuracy of the proposed model compared to a similar model that did not take into account exogenous variables. This finding demonstrates the indisputable potential of using a SARIMAX for long-term wind speed forecasting.

The purpose of this master thesis is to investigate the possibility to refine the control system of turbochargers in petrol engines by introducing turbo speed measurement. This thesis also investigates possible control enhancement from an electric wastegate actuator compared with a traditional pneumatic actuator. During the thesis work the control problem is divided into 3 sub systems: boost pressure controller, turbo speed controller, and electric actuator controller. The design procedure of the controllers follows model-based method in which a simulation model for engine and a simulation model for electric actuator are used. The designed controller is then implemented and evaluated in an engine test cell. The result of the thesis work shows that the electric wastegate actuator is preferred as it delivers consistent actuation speed and accurate positioning which favours model-based design that requires exact wastegate position. Although the purposed controller structure that uses turbo speed measurement cannot yet achieve faster generation of boost pressure by the end of the thesis work, the use of turbo speed sensor as controller feedback still shows potential to enhance the boost controller and ease the controller design, as the turbo speed measurement can reflect the boost pressure faster and is less sensitive to the disturbances in the air flow.