This thesis presents the results of a research project which sought to find links between driver subjective ratings and objective measures of vehicle handling. The experimental data used in this project has been made available from a previous research project. The experimental data was collected using a prototype vehicle which was used in 16 different configurations. Objective data was collected based around the ISO defined steady state, step input, and frequency response tests. Subjective assessments were collected from eight trained test drivers using a numerical rating scale to a questionnaire covering various aspects of vehicle handling. Analysis of the subjective assessments has been done to identify any shortcomings that may affect any subsequent analysis. From the literature review, an approach that claims to relate four simple objective metrics to subjective measures of vehicle handling has been developed in two new ways. Firstly, the proposal was tested [1] with the large amount of subjective data available to see if good levels of correlation could be found between the proposed metrics and driver subjective ratings to specific handling questions. Secondly, the method was extended to include further simple metrics to try and improve links between the subjective and objective data [2]. Non-linear relationships in the correlation of subjective vs. objective data have been investigated for the first time [3] using non-linear genetic algorithms, which, in addition have not previously been used to correlate driver subjective ratings with objective measures that describe vehicle handling. From the results, it has been possible to specify ranges of preferred values of objective metrics in order to produce a subjectively satisfying vehicle. Finally, the work discusses how the results obtained can be used by engineers to aid the vehicle design and development process.

<p> Vehicular communications systems may one day save lives, reduce fuel consumption, and advance connectivity, but they may also transmit information which could be deanonymized to obtain personal information. Vehicle location data are of special concern because they could be used maliciously. This dissertation presents a systematic study resulting in novel definitions, metrics and methods for evaluating and applying location privacy preserving protocols specifically in vehicular settings.</p><p> Previous work in vehicular network privacy has not thoroughly considered vehicular mobility patterns. Previous work in vehicular network privacy has not solved the problem of collusion between MAC layer and application layer attackers. As defenses against location privacy attacks, previous work has favored the privacy methods of anonymization and obfuscation, but these methods have weaknesses. Spatial-temporal cloaking, for example, requires overhead of trusted third parties, and provides little protection in low vehicle densities especially when applications require frequent precise location data. Little published work has addressed the "location" part of location privacy, the geographical distance of location privacy, focusing instead on the size of the anonymity set. The need for new metrics is indicated.</p><p> The present research addresses these issues. In addition to new definitions and metrics, this study develops privacy methods which would (1) accommodate vehicular mobility patterns, (2) defend against collusion by MAC and application layer attackers, (3) produce privacy solutions which depend on cooperation neither by large numbers of other motorists nor by trusted third parties, and (4) function in low vehicle densities, notably during the transition period between system initialization and full saturation, (5) provide protection even when applications require frequent and precise location queries, and (6) provide protection over a geographical range beyond a vehicle's wireless communications range and provide protection over measurable and lengthy spans of time. Finally, it presents a new metric for measuring privacy (KDT), an equation to estimate the safety impact of privacy protocols (SSTE), and three new privacy models, Endpoint Protection Zones (EPZ), Privacy by Decoy (PBD) and Random Rotation of Vehicular Trajectory (RRVT).</p>

Flash boiling may be defined as the finite-rate mechanism that governs phase change in a high temperature liquid that is depressurized below its vapor pressure. This is a transient and complicated phenomenon which has applications in many industries. The main focus of the current work is on modeling flash boiling in injectors used in engines operating on the principle of gasoline direct injection (GDI). These engines are prone to flash boiling due to the transfer of thermal energy to the fuel, combined with the sub-atmospheric pressures present in the cylinder during injection. Unlike cavitation, there is little tendency for the fuel vapor to condense as it moves downstream because the fuel vapor pressure exceeds the downstream cylinder pressure, especially in the homogeneous charge mode. In the current work, a pseudo-fluid approach is employed to model the flow, and the non-equilibrium nature of flash boiling is captured through the use of an empirical time scale. This time scale represents the deviation from thermal equilibrium conditions. The fuel composition plays an important role in flash boiling and hence, any modeling of this phenomenon must account for the type of fuel being used. In the current work, standard, NIST codes are used to model single component fluids like n-octane, n-hexane, and water, and a multi-component surrogate for JP8. Additionally, gasoline-ethanol blends are also considered. These mixtures are azeotropic in nature, generating vapor pressures that are higher than those of either pure component. To obtain the properties of these fuels, two mixing models are proposed that capture this non-ideal behavior. Flash boiling simulations in a number of two and three dimensional nozzles are presented, and the flow behavior and phase change inside the nozzles is analyzed in detail. Comparison with experimental data is performed in cases where data are available. The results of these studies indicate that flash boiling significantly affects the characteristics of the nozzle spray, like the spray cone angle and liquid penetration into the cylinder. A parametric study is also presented that can help understand how the two different time scales, namely the residence time in the nozzle and the vaporization time scale, interact and affect the phenomenon of flash boiling.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.