Doctor of Philosophy / Department of Statistics / John E. Boyer Jr., Dallas E. Johnson / A crossover design is an experimental design in which each experimental unit receives a series of experimental treatments over time. The order that an experimental unit receives its treatments is called a sequence (example, the sequence AB means that treatment A is given first, and then followed by treatment B). A period is the time interval during which a treatment is administered to the experimental unit. A period could range from a few minutes to several months depending on the study. Sequences usually involve subjects receiving a different treatment in each successive period. However, treatments may occur more than once in any sequence (example, ABAB). Treatments and periods are compared within subjects, i.e. each subject serves as his/her own control. Therefore, any effect that is related to subject differences is removed from treatment and period comparisons. Carryover effects are residual effects from a previous treatment manifesting themselves in subsequent periods. Crossover designs both with and without carryover are traditionally analyzed assuming that the response due to different treatments have equal variances. The effects of unequal variances on traditional tests for treatment and carryover difference were recently considered in crossover designs assuming that the response due to treatments have unequal variances with a compound symmetry correlation structure. The likelihood function for the two treatment/two sequence crossover design has closed form maximum likelihood solutions for the parameters at both the null hypothesis, H0 : sigma_A^2 =\sigma_B^2, and at alternative hypothesis, HA : not H0. Under HA : not H0, the method of moment estimators and the maximum likelihood estimators of sigma_A^2,sigma_B^2 and rho are identical. The dual balanced design, ABA=BAB, which is balanced for carryover effects is also considered. The dual balanced design has a closed form solution that maximizes the likelihood function under the null hypothesis, H0 :sigma_A^2=sigma_B^2, but not for the alternative hypothesis, HA : not H0. Similarly, the three treatment/three sequence crossover design, ABC=BCA=CAB, has a closed form solution that maximizes the likelihood function at the null hypothesis, H0 : sigma_A^2=sigma_B^2 = sigma_C^2, but not for the alternative hypothesis, HA : not H0. An iterative procedure is introduced to estimate the parameters for the two and three treatment crossover designs. To check the performance of the likelihood ratio tests, Type I error rates and power comparisons are explored using simulations.

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On se propose dans cette thèse de modéliser le système pilote-véhicule dans une tâche de conduite de fauteuils roulants électriques par des personnes handicapées ayant une déficience motrice sévère. L'objectif est double. Il est tout d'abord descriptif au sens où l'on va chercher à mieux comprendre les spécificités de la commande d'un fauteuil électrique par des personnes handicapés moteurs. Le second objectif est normatif : le modèle pilote-fauteuil doit permettre de définir le mode de comportement optimal de la personne dans une situation de conduite donnée. Ceci induit une méthode d'analyse objective du pilotage de fauteuil. Le premier chapitre, bibliographique, porte sur les modèles pilote-véhicule relatés dans la littérature. Le second chapitre décrit la conception et la validation de notre simulateur de conduite en fauteuil électrique. Le troisième et le quatrième portent sur l'application des modèles Crossover et OPCM. Les résultats obtenus montrent que ces deux modèles ont des domaines d'applicabilité complémentaires dans notre contexte d'étude / In this thesis we propose to model the pilot-vehicle system made up of a person with a severe motor disability and of an electric wheelchair. The first goal is descriptive: we try to better understand the specificities of the control of an electrical wheelchair. The second goal is normative: the pilot-wheelchair model should define the optimal control mode of the wheelchair in a given situation. This should induce an objective analysis method of the piloting of the wheelchair. The first chapter of the report is devoted to a bibliographical study related to the various pilot-vehicle models. The second chapter describes the design and the validation of our wheelchair driving simulator. The third and the fourth chapters relate to the application of the Crossover models and the OPCM model. The results obtained show that these two models have complementary fields of application in our context of study

The mortality rate for elderly pedestrians struck by vehicles is the highest of any age group, approaching 30% in several large series. Currently, there is a lack of epidemiological studies of the risk factors associated with elderly pedestrian injury; in particular, few prospective studies of elderly pedestrian injuries have been performed. The primary purpose of this project was to identify risk factors that will lead to the development and implementation of effective prevention strategies to reduce the risk of pedestrian injury in this vulnerable population. The project had three phases. In phase 1, pilot studies were performed and identified potential risk factors for elderly pedestrians and confirmed their ability to recall accident details. Risk factors identified included certain walking and street crossing behaviors, as well as the lack of use of assistive devices. In Phase 2, the relatively new case-crossover design was utilized to investigate the association of transient (proximate) triggers or exposures with elderly pedestrian injuries. The relative risk of injury if not obeying the traffic signal is five-fold (odds ratio = 5.2; 95% confidence interval = 1.8 – 15.1). Risk factors such as use of sedating or mood altering medications, or the use of alcohol did not have sufficient discordance for analysis. The behavioral findings suggested that educational programs and behavioral modification might play an important role in designing future interventions. Therefore, in Phase 3, an elderly pedestrian safety program called Safe Crossings was created and evaluated. Over 700 subjects participated in the programs, with 99% reporting they felt it was an important topic and 93% acknowledging they learned something from the program. Focus groups were also utilized to help refine the content and delivery of the program. Posters and brochures were created and distributed in English, Spanish and Creole. The program is now set for wider dissemination and validation.

Since the mid-1980s, California's juvenile justice system has been struggling to address two phenomena: crossover youth and the policy of dual jurisdiction. Crossover youth are children who are simultaneously involved in the child welfare and juvenile justice systems; in conjunction, the policy of dual jurisdiction is a policy that permits juvenile courts to assume collaborative jurisdiction over crossover youth's child welfare and juvenile justice cases. Between 1989 and 2004, the system's actors adhered to California Welfare & Institutions Code (WIC) § 241.1, which prohibited the policy of dual jurisdiction. As a result, the system's actors assigned crossover youth to either the child welfare or juvenile justice system, and these children did not receive proper treatment. However, in January 2005, the California state legislature amended WIC § 241.1 to incorporate Section (e), which is also known as the policy of dual jurisdiction. Subsequently, the system's actors now have the option to assign crossover youth to both the child welfare and juvenile justice systems, and these children can receive holistic services from both systems. Currently, approximately two southern Californian counties implement the policy of dual jurisdiction. This thesis argues that the implementation of dual jurisdiction is necessary as it serves in the best interests of crossover youth by addressing the issue of disproportionate minority contact, decreasing the rates of juvenile recidivism, and increasing the availability of rehabilitative services. This thesis also uses preliminary field research to demonstrate the policy of dual jurisdiction's benefits and to encourage more counties to adopt this policy.

In this study, the flow plates of micro methanol fuel cells are designed and fabricated in-house through MEMS(Micro-Electro-Mechanical System) technology with deep UV lithography manufacturing processes (SU-8 photoresist) and micro electroforming manufacturing processes. The thesis investigates methanol and water crossover in a micro DMFC for serpentine flow field configuration. Experiments are conducted through various experiments with different operating conditions for the anode flow rate (2-10 sccm), cathode flow rate (100-500 sccm), methanol concentration (1, 2 and 3M), and temperature (25, 50 and 75¢J). Experimental results are presented in the form of polarization VI curves and PI curves under the above operating conditions. The experimental results show that the methanol and water crossover flux increases with increases in cell temperatures, methanol concentration and anode pressure drop. It is found that the fuel efficiency of the DMFC is closely related to the methanol crossover. Further examination of the relationship between the methanol crossover and cell performance reveals the possibility of reducing the methanol crossover by optimizing the anode flow rate.

In this thesis, a long-term operation direct methanol fuel cell (DMFC) stack with no performance decay is developed and improved. In a traditional passive portable DMFC, the Methanol solution is storage at anode Reaction chamber. The performance will drop after a short period due to the concentration of Methanol solution becoming lower (about 1.5M). Although High concentration of Methanol solution could increase the operation time, but it will couse crossover to poison the cathode Pt particle, and it is unable to keep long-term operation stably either. In order to achieve long-term operation stably, to maintain the concentration of methanol solution in the anode chamber will be very important. In our fuel supply stack, there are two chambers in the stack to storage methanol and water, and we could control the supplying rate by adjusting the diffusion area to control the diffusion rate of methanol and water. And the methanol solution deliver to anode reaction chamber by cotton tube. If the anode reaction chamber is filled with 1.3¢W, 2M methanol solution and without any fuel supply, operating on the 185mA constant current (82.2mA/cm2 ). The results shows that the performance begin decay about after 15minutes. If the appropriate amount of methanol and water is supplied, the performance can be steady in a long-term operation. But if supply too much methanol solution, the concentration in the anode reaction chamber will rise up, and the high concentration will cause crossover poised the cathode catalyst, and the performance will decay. If supply rate not enough, the concentration in the anode reaction chamber will become lower, and the performance will decay after long-term operation. In this study, based on operate current and the rate of evaporation of methanol solution, to supply appropriate supplying rate and concentration of methanol solution to anode reaction chamber, could keep the performance in a steady output.

Under the impact of the financial tsunami, global economy was weaken, lots of luxury brands¡¦ profits decreased, but trendy brands rise at that time. There are many kinds of trendy brands appear in Taiwan since 2008, and become famous between young people immediately. Trendy brands emphasize with uniqueness¡Bself-expression, not only become the fashion tendency, they also play an important role in teenagers¡¦ sub culture. As trendy brands get popular, some companies want to attract more young people by cooperating with trendy brands. Crossover with trendy brands is the main topic for companies. There is a lack of research about trendy or crossover so far, so this study is based on co-branding theory, analysis the change of consumers¡¦ evaluations about Positive brand emotions, negative brand emotions, involvement, and brand identity after company crossovers with different kinds of trendy brand. Then the study adds fitness between company and trendy brand and self-construal types of consumer as mediators, trying to comprehend the influence. This study finds consumers¡¦ evaluations about positive brand emotions and negative brand emotions will be better if company crossover with trendy brand founded by famous people. But consumers¡¦ evaluations about brand identity will be better if company crossover with both trendy brand founded by famous people and ordinary people. However, fitness between company and trendy brand and consumer¡¦s self-construal types don¡¦t change evaluations after crossover.

Optimization problems are divided into numerical optimization problems and combinatorial optimization problems. Genetic algorithms (GAs) are applied to solve optimization problems widely. GAs with multi-parent crossover are often used to solve numerical optimization problems. However, no effective multi-parent crossover is used for combinatorial optimization problems. Partially mapped crossover (PMX) is the most popular crossover for combinatorial optimization problems. In this thesis, we propose multi-parent partially mapped crossover (MPPMX). A large amount of experimental results show that the improvement ratio of MPPMX reaches 38.63 % over PMX. The p-values of t-test on the difference between MPPMX and PMX range from 10-6 to 10-14, which indicates the significant improvement of MPPMX over PMX.