Today, nonhomogeneous materials are used in many technological applications. Nonhomogeneity can be introduced intentionally in order to improve the thermomechanical performance of material systems. The concept of functionally graded materials (FGMs) is an example of such an application. Nonhomogeneity can also be an intrinsic property of some of the natural materials such as natural soil. The main interest in this study is on the contact mechanics of nonhomogeneous surfaces. There is an extensive volume of literature on the contact mechanics of nonhomogeneous materials. In most of these studies, the elastic gradation is assumed to exist in depth direction. But, it is known that elastic gradation may also exist laterally. This may either occur naturally as in the case of natural soil or may be induced as a result of the applied processing technique as in the case of FGMs. The main objective in this study is therefore to examine the effect of the lateral nonhomogeneities on the contact stress distribution at the surface of an elastically graded material. In the model developed to examine this problem, a laterally graded surface is assumed to be in sliding contact with a rigid stamp of arbitrary profile. The problem is formulated using the theory of elasticity and reduced to a singular integral equation. The integral equation is solved numerically using a collocation approach. By carrying out parametric studies, the effects of the nonhomogeneity constants, coefficient of friction and stamp location on the contact stress distribution and on the required contact forces are studied.

There are a lot more roads being built periodically in most of the countries with the advancement of modern society. In order to promote the overall traffic flow quality within different cities, city traffic management has been playing a more and more essential role during the last few decades. In recent years, a significantly increasing attention has been paid to the management of traffic flow in major cities all over the world. In this thesis, we develop a stochastic dynamic model for urban traffic along with physical constraints characteristic of intersections equipped with traffic light. We assume that the incoming traffic to each stream in an intersection is amenable to the Poisson random process with variable intensity (mean). We introduce expressions for traffic throughput, congestion as well as operator's waiting time for the typical intersection in a city and hereafter define an appropriate objective functional. Afterwards, we formulate an optimization problem and propose the sequential (or recursive) algorithm based on the principle of optimality (dynamic programming) due to Bellman. The solution if implemented is expected to improve throughput, reduce congestion, and promote driver's satisfaction. Because the dynamic programming method is computationally quite intensive, we consider the scenario that one unit traffic stream stands for a specific number of vehicles which actually depends on the volume of traffic flow through the intersection. The system is simulated with inputs described by several distinct nonhomogeneous Poisson processes. For example, we apply the typical traffic arrival rate in Canada with morning peak hour at around 7:30 AM and afternoon peak hour at around 4:30 PM whilst it is also applied with morning rush hour at about 8:00 AM and afternoon rush hour at about 6:00 PM like in China. In the meanwhile, we also present a group of numerical results for the traffic arrival rates that have shorter morning peak-hour period but longer afternoon rush hour period. This may occasionally happen when there are some social activities or big events in the afternoon. In addition, another series of experiments are carried out to illustrate the feasibility of the proposed dynamic model based on the traffic arrival rates with only one peak-hour throughout the whole day. The system is simulated with a series of experiments and the optimization problem is solved by dynamic programming based on the proposed algorithm which gives us the optimal feedback control law. More specifically, the results show that both the optimal traffic light timing allocated for each stream and the congestion broadcast level (CBL) of each road segment during each time segment are found. Accordingly, the corresponding optimal cost can be found for any given initial condition. It is reasonably believed that this stochastic dynamic model would be potentially applicable for real time adaptive traffic control system.

Fiber pushout test models are developed for a fiber-matrix-composite with a nonhomogeneous interphase. Using design of experiments, the effects of geometry, loading and material parameters on critical parameters of the pushout test such as the load-displacement curve and maximum interfacial shear and normal stresses are studied. The sensitivity analysis shows that initial load displacement curve is dependent only on the indenter type and not on parameters such as fiber volume fraction, interphase type, thickness of interphase, and boundary conditions. In contrast, interfacial shear stresses are not sensitive to indenter type, while the interfacial radial stresses are mainly sensitive to fiber volume fraction and the boundary conditions.

No description available.

The diploma thesis deals with the topic of discounts and premiums in the valuation theory. More specifically, it covers the area of entity-level discounts. First part of the thesis is devoted to general theoretical analysis of the topic. Next chapter is dedicated to key person discount and portfolio discount, including empirical evidence, relevant factors of influence, their quantification and several case studies. Final part of the thesis describes possibilities of utilization of these two types of discounts in Czech practice.

In this thesis, we will study issues related to prediction problems and put an emphasis on those arising when recurrent events are involved. First we define the basic concepts of frequentist and Bayesian statistical prediction in the first chapter. In the second chapter, we study frequentist prediction intervals and their associated predictive distributions. We will then present an approach based on asymptotically uniform pivotals that is shown to dominate the plug-in approach under certain conditions. The following three chapters consider the prediction of recurrent events. The third chapter presents different prediction models when these events can be modeled using homogeneous Poisson processes. Amongst these models, those using random effects are shown to possess interesting features. In the fourth chapter, the time homogeneity assumption is relaxed and we present prediction models for non-homogeneous Poisson processes. The behavior of these models is then studied for prediction problems with a finite horizon. In the fifth chapter, we apply the concepts discussed previously to a warranty dataset coming from the automobile industry. The number of processes in this dataset being very large, we focus on methods providing computationally rapid prediction intervals. Finally, we discuss the possibilities of future research in the last chapter.

In this thesis, we will study issues related to prediction problems and put an emphasis on those arising when recurrent events are involved. First we define the basic concepts of frequentist and Bayesian statistical prediction in the first chapter. In the second chapter, we study frequentist prediction intervals and their associated predictive distributions. We will then present an approach based on asymptotically uniform pivotals that is shown to dominate the plug-in approach under certain conditions. The following three chapters consider the prediction of recurrent events. The third chapter presents different prediction models when these events can be modeled using homogeneous Poisson processes. Amongst these models, those using random effects are shown to possess interesting features. In the fourth chapter, the time homogeneity assumption is relaxed and we present prediction models for non-homogeneous Poisson processes. The behavior of these models is then studied for prediction problems with a finite horizon. In the fifth chapter, we apply the concepts discussed previously to a warranty dataset coming from the automobile industry. The number of processes in this dataset being very large, we focus on methods providing computationally rapid prediction intervals. Finally, we discuss the possibilities of future research in the last chapter.

In the thesis there is studied nonhomogenous boundary value problem for the stationary Navier-Stokes system in domains which may have two types of outlets to infinity: paraboloidal and layer type. The boundary is multiply connected. It consists of connected noncompact components, forming the outer boundary, and connected compact components, forming the inner boundary. We suppose that the fluxes over the components of the inner boundary are sufficiently small, while we do not impose any restrictions on fluxes over the infinite components of the outer boundary. We prove that the formulated problem admits at least one weak solution which, depending on the geometry of the domain, may have either finite or infinite Dirichlet integral. / Disertacijoje nagrinėjama stacionari Navjė-Stokso sistema su nehomogenine kraštine sąlyga srityse su išėjimais į begalybę. Bendru atveju išėjimai į begalybę gali būti tiek paraboloidiniai, tiek sluoksnio tipo. Srities kraštą sudaro baigtinis skaičius nekompaktiškų jungių komponenčių, kurios suformuoja išorininį kraštą, ir baigtinis skaičius kompaktiškų jungių komponenčių, kurios suformuoja vidinį srities kraštą. Darydami prielaidą, kad srautai per vidinio krašto komponentes yra pakankamai maži, o srautų dydžiui per išorinio krašto komponentes nedarant jokių apribojimų, įrodome suformuluoto uždavinio bent vieno sprendinio egzistavimą. Priklausomai nuo srities geometrijos, uždavinio sprendinys gali turėti tiek baigtinį, tiek begalinį Dirichlė integralą.

Disertacijoje nagrinėjama stacionari Navjė-Stokso sistema su nehomogenine kraštine sąlyga srityse su išėjimais į begalybę. Bendru atveju išėjimai į begalybę gali būti tiek paraboloidiniai, tiek sluoksnio tipo. Srities kraštą sudaro baigtinis skaičius nekompaktiškų jungių komponenčių, kurios suformuoja išorininį kraštą, ir baigtinis skaičius kompaktiškų jungių komponenčių, kurios suformuoja vidinį srities kraštą. Darydami prielaidą, kad srautai per vidinio krašto komponentes yra pakankamai maži, o srautų dydžiui per išorinio krašto komponentes nedarant jokių apribojimų, įrodome suformuluoto uždavinio bent vieno sprendinio egzistavimą. Priklausomai nuo srities geometrijos, uždavinio sprendinys gali turėti tiek baigtinį, tiek begalinį Dirichlė integralą. / In the thesis there is studied nonhomogenous boundary value problem for the stationary Navier-Stokes system in domains which may have two types of outlets to infinity: paraboloidal and layer type. The boundary is multiply connected. It consists of connected noncompact components, forming the outer boundary, and connected compact components, forming the inner boundary. We suppose that the fluxes over the components of the inner boundary are sufficiently small, while we do not impose any restrictions on fluxes over the infinite components of the outer boundary. We prove that the formulated problem admits at least one weak solution which, depending on the geometry of the domain, may have either finite or infinite Dirichlet integral.

No description available.