Ce mémoire traite d'une méthode bayésienne, analysée par Marchand et Strawderman (2013), pour la construction d'intervalles bayésiens pour des modèles de densités continues avec contrainte sur l'espace des paramètres Θ. Notamment, on obtiendra une classe d'intervalles bayésiens Iπ0,α(.), associés à la troncature d'une loi a priori non informative π0 et générés par une fonction de distribution α(.), avec une probabilité de recouvrement bornée inférieurement par 1-α/1+α. Cette classe inclut la procédure HPD donnée par Marchand et Strawderman (2006) dans le cas où la densité sous-jacente d'un pivot est symétrique. Plusieurs exemples y illustrent la théorie étudiée. Finalement, on présentera de nouveaux résultats pour la probabilité de recouvrement des intervalles bayésiens appartenant à la classe étudiée pour des densités log-concaves. Ces résultats établissent la borne inférieure à 1- 3α/2 et généralisent les résultats de Marchand et al.(2008) tenant sous une hypothèse de symétrie.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Mathematics." Includes bibliographical references (p. 83-85).

The objective of this work is to develop a scheme to minimize a combination of power consumption and congestion delay in communication networks. I model the network as a set of parallel links, with flows that are able to divide their traffic among the links available to them. Power consumption at each link is concave and increasing in the load, with a non-zero intercept at the origin corresponding to idle power consumption. I believe it is possible to minimize the overall power consumption by possibly sharing links and shutting down the idle links, as long as it does not lead to significant congestion in the network. In this project, I focus on developing incentives for flows to choose the minimum cost solution. My solutions involve two elements - (i) a mypopic and selfish controller adopted by each source, which attempts to minimize cost seen by that flow, and (ii) a pricing scheme at each link whose objective is to provide appropriate signals to the controllers at the source. I use ideas drawn from population games to choose the set of source controllers, while I experiment with using marginal costs and weighted Shapley values for the pricing scheme. I show that the weighted Shapley value as a pricing scheme is superior to that of marginal cost pricing in some simple cases.

For synthetic data generation with concave collision objects, two physics simu- lations techniques are investigated; convex decomposition of mesh models for globally concave collision results, used with the physics simulation library Bullet, and a GPU implemented rigid body solver using spherical decomposition and impulse based physics with a spatial sorting-based collision detection. Using the GPU solution for rigid body physics suggested in the thesis scenes con- taining large amounts of bodies results in a rigid body simulation up to 2 times faster than Bullet 2.83.

Magistratūros studijų baigiamojo darbo apimtis 66 puslapiai, kuriuose yra 64 paveikslai ir 4 lentelės. Literatūros sąraše 50 šaltinių. Darbo pradžia 2008 09 01, pabaiga 2010 05 10. Objektas. Keturi skirtingi pobūgniai, kurie skyrėsi savo konstrukcija ir aktyviu separacijos plotu. Tikslas. Nustatyti drėgnų (> 35%) kukurūzų burbuolių iškūlimą, grūdų separaciją pro tiriamus pobūgnius ir grūdų sužalojimą sąlygojančius veiksnius bei pagrįsti racionalias jų vertes. Aktualumas. Pateikto darbo literatūros apžvalgoje išanalizuota kukurūzų grūdų nuėmimo technologijos ir kukurūzų burbuolių kuliamųjų konstrukciniai ypatumai. Atlikta mokslinių tyrimų apžvalga, kurioje išsamiai išanalizuoti kūlimo aparatų technologinių reguliavimų ypatumai, kuliant drėgnas kukurūzų burbuoles ir apibendrinti grūdų separaciją pro pobūgnį sąlygojantys veiksniai. Lietuvoje labai drėgnų (> 35%) kukurūzų burbuolių kūlimas mažai tyrinėtas, todėl būtina išanalizuoti kaip keičiasi iškultų grūdų separacija pro pobūgnį, naudojat skirtingų separacijos plotų pobūgnius. Rezultatai. Eksperimentiniais kukurūzų burbuolių kūlimo tyrimais nustatyti tangentinio kūlimo aparato racionalūs technologiniai parametrai kuliant labai drėgnas kukurūzų burbuoles. Tyrimais pagrįsta, kad pobūgnio aktyvus separacijos plotas ženkliai įtakoja grūdų separaciją. Nustatyta tiekiamų burbuolių srauto įtaka iškultų grūdų separacijai pro atskiras pobūgnio dalis. Taip pat nustatytas kūlimo procesui reikalingos galios poreikis, kuris kinta nuo 1,5... [toliau žr. visą tekstą] / The Master thesis consists of 66 pages, including 64 figures and 4 tables. There are 50 sources in the references. This work was started on the 1st of September 2008 and finished on the 10th of May 2010. The object of the work. Four concaves where the difference between them was their construction and active separation area. The aim of the research. The aim of the research is to define wet (> 35) corn cobs’ threshing, grain separation, factors that determine harm and, also, to motivate their rational values. Relevancy of the research. Certain maize grain harvesting technologies and structural peculiarities of corn cobs threshing-machines’ are analyzed in the literature review. The peculiarities of threshing-machines’ setting while threshing wet corn cobs are analyzed as well. Furthermore, special factors that necessitate grain separation through the concave are also generalized in this thesis. However, extremely wet (> 35) corn cobs’ threshing is only slightly studied in Lithuania. It is essentially important to analyze the shift of the threshing grain separation through the concave, using concaves that have different separation areas. The results. Rational technological parameters of tangential threshing-machine are defined by experimental researches of corn cobs’ threshing. This was done by threshing extremely wet corn cobs. The influence of supplying corn cobs flow to the separation of threshing corns through the particular parts of concave is identified. Finally... [to full text]

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Different universal methods (also called automatic or black-box methods) have been suggested to sample from univariate log-concave distributions. The description of a suitable universal generator for multivariate distributions in arbitrary dimensions has not been published up to now. The new algorithm is based on the method of transformed density rejection. To construct a hat function for the rejection algorithm the multivariate density is tranformed by a proper transformation T into a concave function (in the case of log-concave density T(x) = log(x).) Then it is possible to construct a dominating function by taking the minimum of several tangent hyperplanes which are transformed back by $T^(-1)$ into the original scale. The domains of different pieces of the hat function are polyhedra in the multivariate case. Although this method can be shown to work, it is too slow and complicated in higher dimensions. In this paper we split the $R^n$ into simple cones. The hat function is constructed piecewise on each of the cones by tangent hyperplanes. The resulting function is not continuous any more and the rejection constant is bounded from below but the setup and the generation remains quite fast in higher dimensions, e.g. n=8. The paper describes the details how this main idea can be used to construct algorithm TDRMV that generates random tuples from multivariate log-concave distribution with a computable density. Although the developed algorithm is not a real black box method it is adjustable for a large class of log-concave densities. (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing

A rejection algorithm, called ``transformed density rejection", is presented. It uses a new method for constructing simple hat functions for a unimodal density $f$. It is based on the idea of transforming $f$ with a suitable transformation $T$ such that $T(f(x))$ is concave. The hat function is then constructed by taking the pointwise minimum of tangents which are transformed back to the original scale. The resulting algorithm works very well for a large class of distributions and is fast. The method is also extended to the two- and multidimensional case. (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing

Ce m??moire traite d'une m??thode bay??sienne, analys??e par Marchand et Strawderman (2013), pour la construction d'intervalles bay??siens pour des mod??les de densit??s continues avec contrainte sur l'espace des param??tres ??. Notamment, on obtiendra une classe d'intervalles bay??siens I??0,??(.), associ??s ?? la troncature d'une loi a priori non informative ??0 et g??n??r??s par une fonction de distribution ??(.), avec une probabilit?? de recouvrement born??e inf??rieurement par 1-??/1+??. Cette classe inclut la proc??dure HPD donn??e par Marchand et Strawderman (2006) dans le cas o?? la densit?? sous-jacente d'un pivot est sym??trique. Plusieurs exemples y illustrent la th??orie ??tudi??e. Finalement, on pr??sentera de nouveaux r??sultats pour la probabilit?? de recouvrement des intervalles bay??siens appartenant ?? la classe ??tudi??e pour des densit??s log-concaves. Ces r??sultats ??tablissent la borne inf??rieure ?? 1- 3??/2 et g??n??ralisent les r??sultats de Marchand et al.(2008) tenant sous une hypoth??se de sym??trie.

The fluvial morphology of a river channel is a function of the river’s hydrologic and sediment regime. Within-channel river benches are a fluvial feature widely identified in the international literature as geomorphically and ecologically important. Despite this recognition the relationship between bench morphology and the flow regime is poorly understood. The aim of this thesis is to identify the components of the flow regime responsible for the formation and destruction of within-channel benches. / Opinions on the formative flows for benches are highly varied with reports that benches are formed by flows which just inundate the bench; to low-flow periods and sub-bankfull flows; bankfull flows and the annual flood; and moderate, medium and catastrophic sized floods. A large body of research also treats benches as a static morphology. Opinions on destructive flows are similarly varied. There is little empirical evidence for these suggestions. / A bench is most commonly referred to as comprising a horizontal (planar) surface which results from within-channel deposition, but the term is also used to describe bars, floodplains and erosional features. The inability of researchers to agree on the relationships between bench morphology and river hydrology is influenced by the lack of a consistent definition and classification for benches. To adequately address the aim this thesis is presented in two parts: Part A addresses bench nomenclature and provides a sound basis for Part B which addresses the processes of bench formation and destruction. (for complete abstract open document)