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Songsakul, Thitima. "Problems in contracting for biodiversity use and conservation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59536.pdf.
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Zhang, Mei. "Some problems on conservation laws and Vlasov-Poisson-Boltzmann equation /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ma-b23749465f.pdf.
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Thesis (Ph.D.)--City University of Hong Kong, 2009."Submitted to Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves [90]-94)
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Balfoussias, S. S. "Problems in modelling industrial demand for fuels." Thesis, University of York, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372766.
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Dincer, Senay Ayse. "Technological Properties And Conservation Problems Of Some Medieval Bricks And Tiles." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614260/index.pdf.
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The aim of this study is to examine the technology of the relatively deteriorated historic tile, brick and mortar samples of Sivas Gök Medrese and Tokat Gö
k Medrese. Their main deterioration factors were analyzed mainly as salt weathering. It was examined in detail, and the possible desalination methods were discussed. For this purpose, the studies were carried out with a field survey and laboratory experiments on the two sites. Documentation of visual decay forms of Tokat Gö
k Medrese were done with AutoCAD. The density and porosities of tile body and mortar samples were determined by using RILEM standards. The pore size distributions of tile and mortar samples were examined by Mercury Intrusion Porosimetry. Modulus of elasticity of tile body and mortar samples was determined and compared with the other Seljuk building materials. Mineralogical compositions of the tile body and glaze, adhesive tile mortars of Sivas Gö
kmedrese and Tokat Gö
kmedrese were analyzed with X-Ray Powder Diffraction (XRD). Their microstructure and chemical compositions were determined by using Scanning Electron Microscope coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX). The salts were determined for various methods such as spot tests and XRD analyses. The possible treatment methods of salt crystallization were discussed according to the properties of the examined samples. One of the most essential causes of decay factor was salt crystallization for the two buildings which causes detachment and loss of tiles. The deteriorations were distributed over the upper and lower sides of the wall which were close to the dampness zones from the roof and above ground. The experiments proved different kinds of salts such as thenardite, sylvite, halite, natrite, nitratine and niter coming from the ground and the restoration materials such as cement based mortars. The relative humidity of the environments was compared with that of salt characteristics. It was proved that the tiles were adversely affected from salt crystallization. The best desalination method was discussed. Advection method by using poultices was based on the transformation of ions through the flowing moisture. The most prominent characteristic of the poultices must have smaller pore size distribution than original salty materials. The pore size distributions of the tiles and gypsum mortars were determined to compare and chosen the best poultice from the literature. It was concluded that kaolin-sand-based poultices having known properties was the best one as considering the pore size distribution of the tiles and mortars. The study on material properties and desalination process was expected to help different monuments having salt problem.
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Boussaa, Djamel. "Urban conservation in North Africa and the Gulf : problems, challenges and opportunities." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445957.
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Şerifaki, Kerem Böke Hasan. "Conservation problems of historic wall paintings of taxiarhis church in cunda, ayvalık/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/mimarirestorasyon/T000393.pdf.
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Liu, Li. "Energy conservation in wireless sensor networks and related problems of graph theory." Paris 11, 2008. http://www.theses.fr/2008PA112223.
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Cette thèse est divisée en deux grandes parties selon le domaine de recherche :le problème de conservation d’énergie dans les réseaux des nœuds sans fil et le problème de la planification des grilles dans le système informatique. Le chapitre 1 introduit de nouveaux problèmes des WSNs se posent compare aux réseaux traditionnels et les réseaux traditionnels et les réseaux sans fil. Le chapitre 2 adresse une application qui surveille une série d’objectifs avec des emplacements connus par un ensemble de nœuds capteurs dans un WSN hétérogène. Plus loin, dans le chapitre 3, nous étudions le problème sous des conditions spécifiques. En se basant sur le modèle décrit dans les chapitres 2 et 3, nous continuons à supposer que le temps de travail d’un nœud capteur seulement pour la connexion est d fois, celui de la surveillance et la connexion. Dans le dernier chapitre, nous étudions le problème de maximiser la durée de vie et le problème de minimiser le retard, tous les deux sont liés au problème de routage dans les WSN pistant un mobile. Une autre question qu’on étudie dans cette thèse est la planification des grilles dans le système informatique. Le chapitre 6 tente de répondre à la première question, que ce soit. Dans ce chapitre, nous introduisons une nouvelle approche qui respecte les taches parallélismes pour l’informatique de grille. Le chapitre 7 tente de donner un nouveau modèle du système des grilles pour garantir la qualité de planification. Ce chapitre est censé résoudre le problème de savoir comment répartir l’optimale des ressources et adaptative dans la dynamique, évolutive et la distribution contrôlée environnement réseauThis thesis is divided into two major parts according to the research fields : the energy conservation problems in wireless sensor networks and the scheduling problems in grid computing systems. Chapter 1 introduces the emergence of wireless sensor networks and its characteristics according to which the new problems of wireless sensor networks arise compared with the traditional network and wireless networks. Chapter 2-4 present the problem of energy conservation with coverage. We address an application which monitors a set of targets with coverage. We address an application which monitors a set of targets with known locations by a set of sensor nodes in heterogeneous wireless sensor networks. For further studies, we consider this problem under some specific conditions. We consider the wireless sensor networks satisfying that each node monitors one target or just for connection. Furthermore, we continue this work and defines the working time of a node is exactly d times. In chapter 5, present the efficient data routing problem for mobile tracking wireless sensor networks. Another issue we study in this thesis is about scheduling problems in grid computing systems. In chapter 6, we introduce a new approach that is with respect to job parallelism for computational grid. Chapter 7, tries to give a new grid system model to guarantee the quality of a schedule. This chapter is supposed to solve the problem of how to allocate the resources optimally and adaptively in the dynamic, scalable and distribute-controlled grid environment
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Bailey, Catherine Aileen. "Archival theory and machine readable records : some problems and issues." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27685.
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It is a common feeling among archivists that the basic principles of archival theory may have to be examined and redefined in light of the development of computer technology. This need exists not so much because archivists are currently faced with a new and unfamiliar medium, but because the new technology changes not only the uses made of the information but also the way in which we perceive it.
The many attempts to approach the problem in the last twenty years have tended to be focused on single archival functions rather than on fundamental archival principles, and the solutions proposed were essentially practical. This thesis takes a global approach to archival theory and tries to answer the general question: are traditional archival principles valid as a guide in the treatment of machine readable records? In order to answer this question, the thesis puts into relationship the terminologies of computer and archival science, analyses and reconciles them, and proceeds to examine the basic concepts of the nature of archives and records, their life cycle, their appraisal, arrangement and methods of communication, and studies their application to machine readable records. The conclusion of this study is that the theoretical foundation of archival science is valid for the management of all archival documents regardless of their physical medium, and that any differences in treatment are a result of practical application of the theory. However, the development and diffused use of computer technology have opened new areas of concern to all archivists which must be explored from a theoretical perspective. Archival science does not, therefore, need to be redefined, but merely expanded.Arts, Faculty of
Library, Archival and Information Studies (SLAIS), School of
Graduate
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Lee, Wan Lung. "Moving mesh methods for singular problems in two dimensions." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/596.
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Yong, Darryl H. "Solving boundary-value problems for systems of hyperbolic conservation laws with rapidly varying coefficients /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6760.
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Pettersson, Per. "Uncertainty Quantification and Numerical Methods for Conservation Laws." Doctoral thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-188348.
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Conservation laws with uncertain initial and boundary conditions are approximated using a generalized polynomial chaos expansion approach where the solution is represented as a generalized Fourier series of stochastic basis functions, e.g. orthogonal polynomials or wavelets. The stochastic Galerkin method is used to project the governing partial differential equation onto the stochastic basis functions to obtain an extended deterministic system. The stochastic Galerkin and collocation methods are used to solve an advection-diffusion equation with uncertain viscosity. We investigate well-posedness, monotonicity and stability for the stochastic Galerkin system. High-order summation-by-parts operators and weak imposition of boundary conditions are used to prove stability. We investigate the impact of the total spatial operator on the convergence to steady-state. Next we apply the stochastic Galerkin method to Burgers' equation with uncertain boundary conditions. An analysis of the truncated polynomial chaos system presents a qualitative description of the development of the solution over time. An analytical solution is derived and the true polynomial chaos coefficients are shown to be smooth, while the corresponding coefficients of the truncated stochastic Galerkin formulation are shown to be discontinuous. We discuss the problematic implications of the lack of known boundary data and possible ways of imposing stable and accurate boundary conditions. We present a new fully intrusive method for the Euler equations subject to uncertainty based on a Roe variable transformation. The Roe formulation saves computational cost compared to the formulation based on expansion of conservative variables. Moreover, it is more robust and can handle cases of supersonic flow, for which the conservative variable formulation fails to produce a bounded solution. A multiwavelet basis that can handle discontinuities in a robust way is used. Finally, we investigate a two-phase flow problem. Based on regularity analysis of the generalized polynomial chaos coefficients, we present a hybrid method where solution regions of varying smoothness are coupled weakly through interfaces. In this way, we couple smooth solutions solved with high-order finite difference methods with non-smooth solutions solved for with shock-capturing methods.
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Leung, Wai-hung, and 梁偉雄. "The conservation of coastal wetlands, especially the Mai Po marshes, in Hong Kong: problems and prospects." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31253441.
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Bertsimas, Dimitris J., and Jose Nino-Mora. "Conservation Laws, Extended Polymatroids and Multi-Armed Bandit Problems; A unified Approach to Indexabel Systems." Massachusetts Institute of Technology, Operations Research Center, 1993. http://hdl.handle.net/1721.1/5203.
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We show that if performance measures in stochastic and dynamic scheduling problems satisfy generalized conservation laws, then the feasible space of achievable performance is a polyhedron called an extended polymatroid that generalizes the usual polymatroids introduced by Edmonds. Optimization of a linear objective over an extended polymatroid is solved by an adaptive greedy algorithm, which leads to an optimal solution having an indexability property (indexable systems). Under a certain condition, then the indices have a stronger decomposition property (decomposable systems). The following classical problems can be analyzed using our theory: multi-armed bandit problems, branching bandits. multiclass queues, multiclass queues with feedback, deterministic scheduling problemls. Interesting consequences of our results include: (1) a characterization of indexable systems as systems that satisfy generalized conservation laws, (2) a. sufficient condition for idexable systems to be decomposable, (3) a new linear programming proof of the decomposability property of Gittins indices in multi-armed bandit problems, (4) a unified and practical approach to sensitivity analysis of indexable systems, (5) a new characterization of the indices of indexable systems as sums of dual variables and a new interpretation of the indices in terms of retirement options in the context of branching bandits, (6) the first rigorous analysis of the indexability of undiscounted branching bandits, (7) a new algorithm to compute the indices of indexable systems (in particular Gittins indices), which is as fast as the fastest known algorithm, (8) a unification of the algorithm of Klimov for multiclass queues and the algorithm of Gittins for multi-armed bandits as special cases of the same algorithm. (9) closed form formulae for the performance of the optimal policy, and (10) an understanding of the nondependence of the indices on some of the parameters of the stochastic schediiuling problem. Most importantly, our approach provides a unified treatment of several classical problems in stochastic and dynamic scheduling and is able to address in a unified way their variations such as: discounted versus undiscounted cost criterion, rewards versus taxes. preemption versus nonpreemption, discrete versus continuous time, work conserving versus idling policies, linear versus nonlinear objective functions.
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Haenraets, Jan H. M. "Identifying key problems regarding the conservation of designed landscapes : designed landscapes of the recent past." Thesis, De Montfort University, 2010. http://hdl.handle.net/2086/3880.
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The purpose of the study was to improve the understanding of the present situation and the key problems regarding the conservation of designed landscapes of the recent past. Another aim was to investigate roles and initiatives undertaken by key stakeholders and recommend key areas for measures and action to enhance the conservation and protection of designed landscapes of the recent past. The emphasis of the research was on the United Kingdom but relevant findings and actions from an international context were included. A qualitative method was applied using the between-method triangulation research methodology, which combined two methods of investigation, namely data triangulation and theory triangulation. Theory triangulation allowed for an investigation of the wider context or ‘the general’ and a comparison of findings from published sources and records, including an examination of the existing inventories and the roles and initiatives of key stakeholders. The data triangulation used a case study survey, with questionnaires and interviews, to enable the collection and analysis of data from different categories of stakeholders from a site-specific perspective or ‘the particular’ context. The case study survey investigated eleven case study sites using questionnaires and interviews. A total of 146 respondents were contacted and 103 completed responses were received. The results revealed that several recommendations for actions to improve the conservation and protection of heritage of the recent past exist, and that general conservation principles and methodologies exist for the conservation of designed landscapes, but that a lack of recognition and awareness for the significance of designed landscapes of the recent past results in poor implementation of such principles, and the continuing destruction and disfigurement of significant sites. The findings of the study led in the conclusions to the preparation of recommendations for measures and actions by stakeholders, to improve the protection and conservation of landscapes of the recent past.
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Leung, Wai-hung. "The conservation of coastal wetlands, especially the Mai Po marshes, in Hong Kong : problems and prospects /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17457403.
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Frenzel, David [Verfasser]. "Weighted Essentially Non-Oscillatory Schemes in Optimal Control Problems Governed by Nonlinear Hyperbolic Conservation Laws / David Frenzel." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219476986/34.
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Makrodimitri, Magdalini. "Sustainability and heritage conservation : a study of the problems of heating and thermal comfort in churches in the UK." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/264994.
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This PhD thesis looks at the issue of heating historic churches. These structures pose particular challenges: they consist of large high volumes, they are composed of materials that are vulnerable to changes in indoor microclimate, they usually possess fabric of low energy efficiency, it is often very difficult to insert new systems without damaging the historic fabric, and they are only very intermittently occupied. Churches are thus particularly difficult to heat satisfactorily; most early churches were entirely unheated. Later, local heating, such as stoves, were introduced to respond to congregations’ demand for comfort. Newer churches then started being built with heating systems from the start. Although these were rarely satisfactory, modern solutions have generally either attempted to provide low-level continuous background heating or concentrated on heating the congregation or a combination of the two. This thesis starts by looking at existing systems for heating churches and the current literature used to establish so-called best practice. It then sets out to investigate whether these solutions are actually working. It starts by establishing the ideal environmental conditions for conservation of the fabric. It uses existing literature on the conservation of museum artefacts, looking at each material found in churches in turn to map the various requirements and see if a set of conditions can be found that will ensure preservation of all the materials involved. Next, the thesis uses monitoring to establish what conditions actually exist in historic churches. Four churches in Cambridge were chosen to conduct an on-site survey. The four case studies adopt different modern heating solutions and each was carefully monitored throughout the year to establish what the exact conditions were. At the same time the thesis recorded thermal comfort and energy performance. There has been no study that brings together information on proper environmental conditions for protection of all the various categories of materials, perceived thermal comfort and energy performance in church buildings so this thesis sets out to provide one. The thesis shows that most modern heating strategies for historic churches fail to satisfy all three strands of environmentally sustainable performance indicators for church buildings, i.e. energy performance, thermal comfort, and the preservation of the historic fabric. It ends by tentatively suggesting how these challenges might be approached. The final section of the thesis details the limitations of the study and the various areas that require further study. Overall the study seeks to provide a useful survey of the existing literature on the subject and raise some important questions about the current strategies being employed for heating historic churches. Although the study is restricted to examples in a relatively small geographical area, the conclusions could be applied generally to other Northern European examples and the implications apply not only to other churches but also similar large-volume historic buildings such as town halls, dining halls and guild halls all over Europe.
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Wain, Leonie Alison, and n/a. "Investigating the condition of organic coatings on metals: electrochemical evaluation techniques in a conservation context." University of Canberra. Resources, Environmental & Heritage Sciences, 2002. http://erl.canberra.edu.au./public/adt-AUC20050726.144111.
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Electrochemical techniques have potential for use in conservation, both to evaluate the
protectiveness of existing coatings on metal artefacts and to evaluate potential new conservation
coatings. Three electrochemical methods have been examined in this study for
their applicability to conservation problems. Corrosion Potential Measurement is simple
but provides only minimal information on the corrosion processes occurring in an electrochemical
system. Electrochemical Impedance Spectroscopy provides both mechanistic
and predictive information on coating performance, but the data are complex to interpret
and measurements require equipment that is at present too bulky for effective on-site use
and beyond the budget of most conservation laboratories. Electrochemical Noise Measurement
can be performed using cheap, portable instrumentation and theoretically requires
relatively simple statistical processing and interpretation, making it attractive for
conservation applications. This project looks at the development of a simple, low cost
electrochemical noise measurement system for conservation needs, and uses it to compare
Electrochemical Noise Measurement with the other two techniques.
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Chen, Weitao. "Fast Sweeping Methods for Steady State Hyperbolic Conservation Problems and Numerical Applications for Shape Optimization and Computational Cell Biology." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366279632.
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Burns, William C. G. "Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea, and contiguous Area (ACCOBAMS) : problems and prospects." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55150/.
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Perge, Emilie. "Poverty within tropical forest : assets and activities to develop pro-poor forest conservation." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6930/.
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Poverty within forests is often acknowledged but poorly assessed through economic evi- dence. To some extent, this lack of evidence explains why even if forest conservation has positive effects on households' welfare, such benefits are quite limited. This thesis is aimed at investigating in three steps how forest conservation can help poor forest households to improve their welfare. A first chapter deals with assessing poverty of forest households in Bolivia looking at their asset accumulation and allowing for a poverty trap mechanism that may arise, preventing households to be better off. The empirical analysis does not find evidence for the exis- tence of a poverty trap. Households are slowly accumulating assets over time but such an accumulation does not lead to any improvements in their welfare. Households would remain persistently poor. A second chapter focuses on forest households' labour supply and allocations. Using primary data I collected in Cameroon, a non-separable agricultural household model is employed to identify factors influencing household labour supply and allocations into di- verse activities. The empirical results shows that leisure is an inferior good, households working more when having greater income. Furthermore, households participating in for- est activities have higher levels of welfare than households that do not. Increasing prices of forest resources helps households to improve their welfare. The last chapter deals with designing payments for forest conservation so as to encourage forest households to internalise externalities. These payments are theoretically analysed using a principal-agent game in order to define incentives such that a forest group plants and conserves a great number of trees. Payments are non-zero when observing such con- servation levels and equal to zero in all other cases. Doing so creates a virtuous circle on forest resources. Pro-poor conservation schemes as opposed to non-pro poor, are achiev- able with lower payments.
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Pfirsching, Marion [Verfasser]. "A multi-scale model for material flow problems based on a non-local conservation law: simulation and optimization / Marion Pfirsching." München : Verlag Dr. Hut, 2018. http://d-nb.info/1162768134/34.
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Mendes, JociclÃa de Sousa. "Dynamic of landscape of the river estuary apa mundau: space-time evolution and potential environmental." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10320.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorAs unidades de paisagem do litoral cearense possuem um grande valor paisagÃstico, entretanto vÃm sendo utilizadas de forma incorreta, principalmente nas Ãltimas dÃcadas, comprometendo a sustentabilidade ecolÃgica dos ecossistemas e provocando mudanÃas nas caracterÃsticas dos ambientes naturais, bem como no modo de vida das comunidades tradicionais. Nesse contexto, a criaÃÃo de Ãreas de ProteÃÃo Ambiental està sendo vislumbrada como uma alternativa para controlar essas mudanÃas e manter as relaÃÃes ecolÃgicas estabelecidas entre os seres vivos e o ambiente fÃsico. A pesquisa, pois, teve o objetivo de elaborar um diagnÃstico da APA do EstuÃrio do Rio MundaÃ, localizada na costa oeste do estado do Cearà e propor medidas de gestÃo integrada. Para isso, o estudo abrangeu a anÃlise das condiÃÃes geoecolÃgicas da Ãrea, dos usos a que està sendo submetida e dos efeitos decorrentes dessa utilizaÃÃo, por influÃncia de fatores de ordem ambiental e social. O referencial teÃrico utilizado foi o da geoecologia das paisagens, que ofereceu as condiÃÃes de realizar a anÃlise do espaÃo geogrÃfico, a partir da junÃÃo de procedimentos tÃcnicos contemporÃneos das ciÃncias ambientais, como: i) anÃlise do Ãndice de CondiÃÃo de Vida e Moradia (ICV-MO); ii) anÃlise da qualidade da Ãgua, na qual foi realizado um diagnÃstico da situaÃÃo atual do sistema estuarino; iii) tÃcnicas cartogrÃficas, que possibilitaram a realizaÃÃo da anÃlise espaÃo-temporal da APA, verificando a dinÃmica atuante, assim como os usos realizados. A APA possui sistemas ecolÃgicos de grande importÃncia natural e econÃmica para a regiÃo em que estÃo inseridos, mas que vÃm sendo, entretanto, explorados e ocupados de forma incorreta, gerando diversos impactos ambientais e causando degradaÃÃo, tanto pelas intervenÃÃes humanas sem planejamento ambiental como pela falta de cumprimento da legislaÃÃo vigente. Verificou-se que as mudanÃas significativas na paisagem da APA nos Ãltimos cinquenta e quatro anos foram causadas por intensa dinÃmica ambiental e por prÃticas sociais e econÃmicas que contrariam a legislaÃÃo brasileira, tais como ocupaÃÃo indevida da Ãrea de manguezal, mineraÃÃo ilegal nas dunas, deposiÃÃo inadequada de resÃduos sÃlidos e atividades de carcinicultura no leito do rio. Todavia, concluiu-se que a Ãrea do estuÃrio do rio MundaÃ, apesar de apresentar problemas ambientais, sociais e estruturais, ainda mantÃm um ambiente propÃcio ao desenvolvimento com qualidade, desde que sejam revistos a funcionalidade e os objetivos da APA para a adoÃÃo e o exercÃcio de planos de gestÃo e de fiscalizaÃÃo de forma apropriada e contÃnua.
The landscape units of the coastal zone of the Brazilian state of Cearà have considerable scenic value, but have been exploited inadequately, especially in recent decades. This process has affected the ecological sustainability of the local ecosystems and provoked profound changes in the characteristics of both natural environments and the lifestyle of local traditional communities. In this context, the creation of environment protection areas (known as APAs in Brazil) is considered to be a practical alternative for the control of these changes and the management of the ecological relationships established between living organisms and the physical environment. The objective of the present study was thus to provide a diagnosis of the APA of the estuary of the Mundaà River, located in western CearÃ, and propose measures for the integrated management of the area. The study includes the analysis of the geo-ecological conditions of the area, the forms in which it is being exploited, and the effects of this use, based on the evaluation of both social and environmental factors. The study was based on a landscape geo-ecological approach, which offers a baseline for the analysis of geographic space, derived from the integration of modern technical environmental science procedures, such as (i) the analysis of the Living and Dwelling Conditions Index (ICV-MO); (ii) analysis of water quality, based on a diagnosis of the current situation of the estuarine system; (iii) cartographic techniques, which permitted the development of a spatial-temporal analysis of the APA, the identification of the current dynamics, and the types of land use practiced in the area. The APA encompasses ecological systems that have considerable natural and economic value for the region in which they are located, but which are currently being exploited and occupied inadequately. This has generated a variety of environmental impacts and caused degradation, not only through the lack of environmental planning, but also disrespect for the current legislation. A number of significant changes were identified in the landscape of the APA over the past 54 years, which have been caused by the intense dynamics of the natural environment, as well as social and economic practices, which have ignored Brazilian legislation, such as the gratuitous occupation of mangroves, illegal mining of dunes, inadequate disposal of solid waste, and shrimp farming in the river bed. Despite the environmental, social, and structural problems identified during the present study, the present study concluded that the estuary of the Mundaà River can still be developed satisfactorily, as long as the objectives and operation of the APA can be adapted to include continuous management and monitoring procedures appropriate to the characteristics of the area.
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Hartel, Colleen M. "The Role of Wildlife Value Orientations in Framing Interactions with Wildlife Near the Home: A Mixed-methods Analysis of Self-reported Problems with Wildlife." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1525541681974028.
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Abboud, Feriel. "Restoration super-resolution of image sequences : application to TV archive documents." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1038/document.
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Au cours du dernier siècle, le volume de vidéos stockées chez des organismes tel que l'Institut National de l'Audiovisuel a connu un grand accroissement. Ces organismes ont pour mission de préserver et de promouvoir ces contenus, car, au-delà de leur importance culturelle, ces derniers ont une vraie valeur commerciale grâce à leur exploitation par divers médias. Cependant, la qualité visuelle des vidéos est souvent moindre comparée à celles acquises par les récents modèles de caméras. Ainsi, le but de cette thèse est de développer de nouvelles méthodes de restauration de séquences vidéo provenant des archives de télévision française, grâce à de récentes techniques d'optimisation. La plupart des problèmes de restauration peuvent être résolus en les formulant comme des problèmes d'optimisation, qui font intervenir plusieurs fonctions convexes mais non-nécessairement différentiables. Pour ce type de problèmes, on a souvent recourt à un outil efficace appelé opérateur proximal. Le calcul de l'opérateur proximal d'une fonction se fait de façon explicite quand cette dernière est simple. Par contre, quand elle est plus complexe ou fait intervenir des opérateurs linéaires, le calcul de l'opérateur proximal devient plus compliqué et se fait généralement à l'aide d'algorithmes itératifs. Une première contribution de cette thèse consiste à calculer l'opérateur proximal d'une somme de plusieurs fonctions convexes composées avec des opérateurs linéaires. Nous proposons un nouvel algorithme d'optimisation de type primal-dual, que nous avons nommé Algorithme Explicite-Implicite Dual par Blocs. L'algorithme proposé permet de ne mettre à jour qu'un sous-ensemble de blocs choisi selon une règle déterministe acyclique. Des résultats de convergence ont été établis pour les deux suites primales et duales de notre algorithme. Nous avons appliqué notre algorithme au problème de déconvolution et désentrelacement de séquences vidéo. Pour cela, nous avons modélisé notre problème sous la forme d'un problème d'optimisation dont la solution est obtenue à l'aide de l'algorithme explicite-implicite dual par blocs. Dans la deuxième partie de cette thèse, nous nous sommes intéressés au développement d'une version asynchrone de notre l'algorithme explicite-implicite dual par blocs. Dans cette nouvelle extension, chaque fonction est considérée comme locale et rattachée à une unité de calcul. Ces unités de calcul traitent les fonctions de façon indépendante les unes des autres. Afin d'obtenir une solution de consensus, il est nécessaire d'établir une stratégie de communication efficace. Un point crucial dans le développement d'un tel algorithme est le choix de la fréquence et du volume de données à échanger entre les unités de calcul, dans le but de préserver de bonnes performances d'accélération. Nous avons évalué numériquement notre algorithme distribué sur un problème de débruitage de séquences vidéo. Les images composant la vidéo sont partitionnées de façon équitable, puis chaque processeur exécute une instance de l'algorithme de façon asynchrone et communique avec les processeurs voisins. Finalement, nous nous sommes intéressés au problème de déconvolution aveugle, qui vise à estimer le noyau de convolution et la séquence originale à partir de la séquence dégradée observée. Nous avons proposé une nouvelle méthode basée sur la formulation d'un problème non-convexe, résolu par un algorithme itératif qui alterne entre l'estimation de la séquence originale et l'identification du noyau. Notre méthode a la particularité de pouvoir intégrer divers types de fonctions de régularisations avec des propriétés mathématiques différentes. Nous avons réalisé des simulations sur des séquences synthétiques et réelles, avec différents noyaux de convolution. La flexibilité de notre approche nous a permis de réaliser des comparaisons entre plusieurs fonctions de régularisation convexes et non-convexes, en terme de qualité d'estimationThe last century has witnessed an explosion in the amount of video data stored with holders such as the National Audiovisual Institute whose mission is to preserve and promote the content of French broadcast programs. The cultural impact of these records, their value is increased due to commercial reexploitation through recent visual media. However, the perceived quality of the old data fails to satisfy the current public demand. The purpose of this thesis is to propose new methods for restoring video sequences supplied from television archive documents, using modern optimization techniques with proven convergence properties. In a large number of restoration issues, the underlying optimization problem is made up with several functions which might be convex and non-necessarily smooth. In such instance, the proximity operator, a fundamental concept in convex analysis, appears as the most appropriate tool. These functions may also involve arbitrary linear operators that need to be inverted in a number of optimization algorithms. In this spirit, we developed a new primal-dual algorithm for computing non-explicit proximity operators based on forward-backward iterations. The proposed algorithm is accelerated thanks to the introduction of a preconditioning strategy and a block-coordinate approach in which at each iteration, only a "block" of data is selected and processed according to a quasi-cyclic rule. This approach is well suited to large-scale problems since it reduces the memory requirements and accelerates the convergence speed, as illustrated by some experiments in deconvolution and deinterlacing of video sequences. Afterwards, a close attention is paid to the study of distributed algorithms on both theoretical and practical viewpoints. We proposed an asynchronous extension of the dual forward-backward algorithm, that can be efficiently implemented on a multi-cores architecture. In our distributed scheme, the primal and dual variables are considered as private and spread over multiple computing units, that operate independently one from another. Nevertheless, communication between these units following a predefined strategy is required in order to ensure the convergence toward a consensus solution. We also address in this thesis the problem of blind video deconvolution that consists in inferring from an input degraded video sequence, both the blur filter and a sharp video sequence. Hence, a solution can be reached by resorting to nonconvex optimization methods that estimate alternatively the unknown video and the unknown kernel. In this context, we proposed a new blind deconvolution method that allows us to implement numerous convex and nonconvex regularization strategies, which are widely employed in signal and image processing
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Ricchiuto, Mario. "Contributions to the development of residual discretizations for hyperbolic conservation laws with application to shallow water flows." Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00651688.
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In this work we review 12 years of developments in the field of residual based discretizations for hyperbolic problems and their application to the solution of the shallow water equations. Fundamental concepts related to the topic are recalled and he construction of second and higher order schemes for steady problems is presented. The generalization to time dependent problems by means of multi-step implicit time integration, space-time, and genuinely explicit techniques is thoroughly discussed. Finally, the issues of C-property, super consistency, and wetting/drying are analyzed in this framework showing the power of the residual based approach.
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Goetz, Claus Rüdiger [Verfasser], and Armin [Akademischer Betreuer] Iske. "Approximate Solutions of Generalized Riemann Problems for Hyperbolic Conservation Laws and Their Application to High Order Finite Volume Schemes / Claus Rüdiger Goetz. Betreuer: Armin Iske." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1045730483/34.
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Goetz, Claus Rüdiger Verfasser], and Armin [Akademischer Betreuer] [Iske. "Approximate Solutions of Generalized Riemann Problems for Hyperbolic Conservation Laws and Their Application to High Order Finite Volume Schemes / Claus Rüdiger Goetz. Betreuer: Armin Iske." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://nbn-resolving.de/urn:nbn:de:gbv:18-65183.
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Alrmah, Masoud Ahmed. "Numerical Investigation Of Solidification." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606140/index.pdf.
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Finite element solution of solidification process in 2-D Cartesian and axisymmetric geometries is investigated. The use of finite element may result in spurious increase of temperature in the field and the selection of the mushy zone range when used as a numerical tool along with the selection of the mesh size results in large errors in the predicted solidification time.
The approach works best for problems where the mushy zone range is finite and the thermal conductivities of both phases are high.
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Queruz, Francisco. "CONTRIBUIÇÃO PARA IDENTIFICAÇÃO DOS PRINCIPAIS AGENTES E MECANISMOS DE DEGRADAÇÃO EM EDIFICAÇÕES DA VILA BELGA." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/7685.
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The development of actions and policies of patrimonial preservation acquires each time more importance for the societies that are trying to preserve its cultural heritages. This work presents a multiple case study performed in the buildings of the Belgian Village, in Saint Maria, in order to identify the most important agents and mechanisms that are involved in the deterioration of these constructions, which are important for the community. The proposal was supported by the premise that only with the knowledge of the factors that take place on the constructions it would be possible to plan its maintenance. This study initiated with the revision of the concepts of conservation and restoration of the cultural heritage, by a historical retrospect, and had arrived to the plural and multifaceted definitions of those terms. Also the pathological characteristics of the constructions, their rehabilitation and problems had been studied. These made possible to describe a proper classification of agents and mechanisms of degradation. The elaborated case studies was performed by field inspection and had allowed a generalized analysis of the more frequent problems and, thus, that would be inferred about the possible involved causes in this process. The results showed that a great set of problems that happen on the buildings occur in the superficial layers in its majority. Also it could be observed that the damages originated by climatic and environmental condition do not possess dependence with some specific type of problem in its majority, what it evidences the actions of recklessness, improper interventions and lack of preventive maintenance in the constructions.O desenvolvimento de ações e políticas de preservação patrimonial adquire cada vez mais importância para as sociedades que buscam preservar as suas heranças, seus bens. Este trabalho apresenta um estudo de caso múltiplo, elaborado sobre as edificações da Vila Belga, de Santa Maria, para identificar os principais agentes e mecanismos envolvidos na deterioração dessas edificações tombadas e importantes para a comunidade. A proposta apoiou-se na premissa de que somente com o conhecimento dos fatores que incidem sobre as edificações torna-se possível planejar sua manutenção. Iniciando-se com a revisão dos conceitos de conservação e restauração do patrimônio cultural, por meio de uma retrospectiva histórica, chegou-se às atuais definições, plurais e multifacetadas. Também foram estudadas as características das edificações, a reabilitação e as manifestações patológicas a que poderiam ser expostas, o que possibilitou elaborar uma classificação própria de agentes e mecanismos de degradação. Os estudos de caso elaborados por meio de levantamentos de campo permitiram que se obtivesse um panorama geral dos processos patológicos mais freqüentes e, assim, que se inferisse sobre as possíveis causas envolvidas nesse processo. Os resultados alcançados mostraram que existe um grande conjunto de patologias que incidem sobre as edificações e que são, em sua maioria, atuantes nas camadas superficiais das elevações. Também se pôde observar que os danos originados pelos condicionantes climáticos e ambientais não possuem, em sua maioria, dependência com algum tipo específico de patologia, o que evidencia as ações de negligência, as intervenções indevidas e a falta de manutenção preventiva nas edificações.
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LIMA, Lidiane dos Santos Monteiro. "Problemas de Riemann para um Sistema Simétrico de Duas Leis de Conservação." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/1972.
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Previous issue date: 2010-04-09In this dissertation we describe the solutions to the Riemann problem for a system of two conservation laws written in the normal from according to classification of Schaeffer-Shearer in [9]. Through changes of variables Schaeffer-Shearer determined the normal form for a nonlinear system of two conservation laws with an isolated umbilical point in state space. The normal form consists of a system of two equations, with homogeneous and quadratic functions of flow that depend only on two parameters. Also in [9] were established four distinct regions in terms of parameters, denoted by I, II, III and IV, in which varying pair of parameters in each region, the curves of waves that make up the solution of the Riemann problem have the same configuration. In this dissertation we consider the case in which the pair of parameters belongs to region IV, and in the particular case in which one of the parameters is null. In this case, the classic Lax criterion for admissibility of shocks (discontinuity solutions) generally is sufficient to obtain uniqueness of solution. Although, for some initial states, it is necessary to admit in solution also the called compressive shocks, which do not satisfy the Lax criterion.
Nesta dissertação determinamos as soluções do problema de Riemann para um sistema de duas leis de conservação escrito na forma normal segundo a classificação de Schaeffer-Shearer, em [9]. Através de mudanças de variáveis, Schaeffer-Shearer determinaram a forma normal para um sistema não linear de duas leis de conservação com um ponto umbílico isolado no espaço de estados. A forma normal consiste de um sistema de duas equações, com funções de fluxo quadráticas homogêneas que dependem apenas de dois parâmetros. Também em [9] foram determinadas quatro regiões distintas no plano dos parâmetros, denotadas por I, II, III e IV, onde, variando o par de parâmetros em cada região, as curvas de onda que compõem a solução do problema de Riemann tem a mesma configuração. Nesta dissertação consideramos o caso em que o par de parâmetros pertence a região IV, e ainda no caso particular em que um dos parâmetros é nulo. Neste caso, o clássico critério de Lax para admissibilidade dos choques (soluções descontínuas), em geral, é suficiente para se obter unicidade de solução. Embora, para alguns estados iniciais, é necessário admitir na solução também os chamados choques compressivos, que não satisfazem o critério de Lax.
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Brown, Peter M. "An investigation of unbalanced forced-air heating systems in historic homes and the potential for resultant moisture problems in the building envelope." Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1214378.
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Unblanced forced-air heating systems create a situation that may be detrimental to the building envelope. These systems create an air pressure differential, which acts as a moisture transport mechanism, which has the potential to carry moisture, through the smallest of openings in the building envelope. Once this warm air enters the wall cavity it comes into contact with the unheated surfaces of the components making up the building envelope, which are below dew point during the heating months. As this moisture-laden air reaches its dew point, condensation occurs.Department of Architecture
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Fogarty, Tiernan. "Finite volume methods for acoustics and elasto-plasticity with damage in a heterogeneous medium /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/6751.
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Laurent-Brouty, Nicolas. "Modélisation du trafic sur des réseaux routiers urbains à l’aide des lois de conservation hyperboliques." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4056.
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Cette thèse se consacre à la modélisation mathématique du trafic routier à l'aide des lois de conservation hyperboliques. Nous nous intéressons plus particulièrement à l’application des modèles macroscopiques en milieu urbain. Les zones urbaines sont désormais régulièrement confrontées à des niveaux de congestion record et à des épisodes de pollution atmosphérique causés par le trafic routier. L’objectif de cette thèse est alors de développer des modèles de trafic qui représentent de manière réaliste l’évolution des véhicules en milieu urbain. Dans un premier temps, nous considérons le modèle Aw-Rascle-Zhang avec relaxation. Nous construisons une suite de solutions approchées à l'aide de la méthode de suivi des fronts (wave-front tracking en anglais) couplée à une méthode de décomposition temporelle (splitting en anglais) en référentiel Lagrangien. Pour chaque valeur du paramètre de relaxation, nous montrons que cette suite converge vers une solution faible et entropique du système pour une donnée initiale à variation bornée. Par la suite, nous calculons une borne supérieure sur la décroissance des ondes positives. Nous démontrons que les solutions du système convergent vers une solution faible du modèle Lighthill-Whitham-Richards (LWR), c'est à dire vers la solution de la loi de conservation scalaire, lorsque le paramètre de relaxation tend vers zéro. Nous concluons par une discussion sur le caractère entropique de cette solution faible du modèle LWR. Dans un second temps, nous proposons un nouveau modèle macroscopique de trafic routier qui préserve le caractère borné de l'accélération des véhicules. Notre modèle couple une Équation aux Dérivées Partielles (EDP), la loi de conservation scalaire, à plusieurs Équations aux Dérivées Ordinaires (EDO), décrivant la trajectoire de véhicules accélérant à taux constant. Ces véhicules sont traités dans le modèle comme des goulots d'étranglement mobiles. Nous proposons la construction de solutions approchées avec un algorithme de suivi des fronts d'ondes et prouvons l'existence et l'unicité de la solution pour le problème de Cauchy associé à une donnée initiale constante par morceaux. Nous produisons ensuite des simulations numériques de notre modèle dans différentes situations urbaines, allant de la résolution du problème de Riemann à la simulation d'un axe urbain comportant plusieurs feux de signalisation. Enfin nous comparons ces simulations aux solutions du modèle LWR appliqué aux mêmes situations. Pour terminer, nous proposons un nouveau modèle macroscopique de trafic routier avec des stockages tampon (buffers en anglais) aux intersections afin de résoudre le modèle LWR sur des réseaux routiers. Ce modèle utilise des buffers de dimension finie, qui garantissent la propagation de la congestion au sein du réseau. Il comporte également des fonctions de répartition de véhicules aux jonctions qui sont dépendantes du temps, et peuvent dès lors être contrôlées au cours du temps. La dynamique du trafic est d'abord établie à l'aide des lois de conservation hyperboliques, conformément au modèle LWR, puis retranscrite dans une formulation de Hamilton-Jacobi. Nous prouvons alors l'existence, l'unicité et la stabilité des solutions vis à vis des données initiales en résolvant un problème de point fixe dans un espace de Banach approprié. La propriété de stabilité garantit que la solution du problème peut être contrôlée et optimisée en modifiant les fonctions de répartition des véhicules aux jonctions. Cela représente une avancée dans la résolution du problème d'assignation dynamique du trafic routier (Dynamic Traffic Assignment en anglais). Pour finir, nous détaillons l'application du modèle à un réseau routier réaliste comportant plusieurs intersections et des routes de longueur finieThis thesis is devoted to the modeling of traffic flow using hyperbolic conservation laws, with a specific focus on urban applications. Urban areas are today facing severe episodes of air pollution and increasing congestion due to traffic. The objective is to overcome some of the current limitations of macroscopic traffic flow models in urban situations. We first study the seminal Aw-Rascle-Zhang model with relaxation. We prove well-posedness of the model using wave-front tracking approximations and splitting technique in a Lagrangian setting. Besides, we provide an estimate on the decay of positive waves. We then show that the solutions of the Aw-Rascle-Zhang system with relaxation converge to a weak solution of the LWR model when the relaxation parameter goes to zero. Finally, we propose a discussion on the entropy aspect of this weak solution of the LWR model. We then propose a new macroscopic traffic flow model accounting for the boundedness of traffic acceleration, which is required for physical realism. Our model is built on the coupling between the scalar conservation law accounting for the conservation of vehicles and a number of ordinary differential equations describing the trajectories of accelerating vehicles, which we treat as moving constraints. We detail a wave-front tracking algorithm to construct approximate solutions of the model, with general flux functions and show existence of solutions to the Cauchy problem for a piecewise constant initial datum. Finally, we provide numerical simulations of the model in different urban situations, from a single Riemann problem to sequences of traffic lights, and confront the results to numerical simulations of the LWR model. Finally, we introduce a new macroscopic traffic flow model with buffers on road networks. This model features buffers of finite size, enabling backward propagation of congestion on the network, and time-dependent routing functions at the junctions. The dynamics are first defined on the level of conservation laws, and then transformed in an Hamilton-Jacobi formulation. We prove existence, uniqueness and stability of the solutions with respect to the routing ratios and initial datum using a fixed-point problem in a proper Banach space. Thanks to stability, the model provides a controllable framework, using routing ratios as control parameters. This represents an advance towards solving the Dynamic Traffic Assignment (DTA) problem. In the end we detail how this framework applies to a classical road network with several intersections and finite-length links
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Dochuk, Darren T. "Redeeming the time, conservative evangelical thought and social reform in Central Canada, 1885-1915." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0001/MQ28191.pdf.
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Brading, Katherine. "Symmetries, conservation laws and Noether's variational problem." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288912.
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Stevens, Ben. "Short-time structural stability of compressible vortex sheets with surface tension." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:378713da-cd05-4b9a-856d-bee2b0fb47ce.
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The main purpose of this work is to prove short-time structural stability of compressible vortex sheets with surface tension. The main result can be summarised as follows. Assume we start with an initial vortex-sheet configuration which consists of two inviscid fluids with density bounded below flowing smoothly past each other, where a strictly positive fixed coefficient of surface tension produces a surface tension force across the common interface, balanced by the pressure jump. We assume the fluids are modelled by the compressible Euler equations in three space dimensions with a very general equation of state relating the pressure, entropy and density in each fluid such that the sound speed is positive. Then, for a short time, which may depend on the initial configuration, there exists a unique solution of the equations with the same structure, that is, two fluids with density bounded below flowing smoothly past each other, where the surface tension force across the common interface balances the pressure jump. The mathematical approach consists of introducing a carefully chosen artificial viscosity-type regularisation which allows one to linearise the system so as to obtain a collection of transport equations for the entropy, pressure and curl together with a parabolic-type equation for the velocity. We prove a high order energy estimate for the non-linear equations that is independent of the artificial viscosity parameter which allows us to send it to zero. This approach loosely follows that introduced by Shkoller et al in the setting of a compressible liquid-vacuum interface. Although already considered by Shkoller et al, we also make some brief comments on the case of a compressible liquid-vacuum interface, which is obtained from the vortex sheets problem by replacing one of the fluids by vacuum, where it is possible to obtain a structural stability result even without surface tension.
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Gisclon, Marguerite. "Etude des conditions aux limites pour des systèmes strictement hyperboliques, via l'approximation parabolique." Lyon 1, 1994. http://www.theses.fr/1994LYO10294.
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On etudie les systemes hyperboliques de lois de conservation en dimension un d'espace, en particulier ce qu'il reste d'une condition aux limites de dirichlet, de neumann ou melee, posee pour une perturbation parabolique du systeme, lorsque le cfficient de diffusion tend vers zero. De telles perturbations ont en general un sens physique dans le probleme qu'on etudie, elles modelisent en effet les effets de dissipation. Dans un premier temps, on montre que les limites de deux problemes differents pour l'equation de burgers, que joseph et le floch avaient decrites par des formules complexes, sont en fait egales. Il s'agit d'un probleme scalaire. Pour des systemes, la couche limite qui se forme dans le cas ou le bord n'est pas caracteristique (le cas caracteristique serait analogue au probleme, toujours ouvert, de la convergence de navier-stokes vers euler dans un domaine borne) est decrite. Par une methode d'energie, on demontre la validite du developpement asymptotique sur un intervalle de temps fini, anterieur a la formation des chocs. Dans le cas du p-systeme notamment, la condition aux limites residuelle est explicitee
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Hua, Jiale. "Glimm type functional and one dimensional systems of hyperbolic conservation laws /." access abstract and table of contents access full-text, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ma-b23749921f.pdf.
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Thesis (Ph.D.)--City University of Hong Kong, 2009."Submitted to Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 88-95)
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Stuch, Benjamin [Verfasser]. "Food Security and Biodiversity Conservation under Global Change / Benjamin Stuch." Kassel : Kassel University Press, 2016. http://d-nb.info/1123731233/34.
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Dymski, Nikodem. "Lois de conservation pour la modélisation de dynamiques de groupe." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4073.
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Cette thèse est consacrée à la modélisation macroscopique du trac routier ou celle-ci décrit le trac avec des variables moyennées sur plusieurs voitures. Il se concentre principalement sur une situation dans laquelle le flux maximal de voitures est limité par un point qui reste fixe sur la route. Grâce à ces considérations, nous pouvons décrire le trafic à des postes de péage et à des chantiers. D'un point de vue mathématique des systèmes hyperboliques de lois de conservation avec condition de contrainte. La recherche est basée sur trois modèles macroscopiques, à savoir le modèle de Lighthill-Witham-Richards (LWR), le modèle Aw-Rascle-Zhang (ARZ) et le modèle de transition de phase (TP). Le but de la thèse est d'établir l'existence et les propriétés d'une solution faible. La thèse comprend 6 chapitres et 2 annexes. Dans le premier chapitre, nous introduisons les idées de base de la modélisation du trafic. Le second chapitre est dédié à une discussion détaillée des modèles macroscopiques de base dans le trac. Dans le troisième chapitre, nous décrivons le modèle LWR contenant une contrainte ponctuelle locale sur le flux. Le quatrième chapitre est dédié au modèle ARZ avec une contrainte ponctuelle locale sur le flux. Nous prouvons là l'existence de la solution faible correspondant au solver de Riemann non conservatif dans la classe des fonctions à variations bornées. Le but est obtenu en montrant la convergence d'une suite de solutions approchées construites à partir de la méthode de Wave Front Tracking. Dans le chapitre 5, nous décrions deux modèles TP avec contrainte ponctuelle locale sur le flux. Ensuite nous étudions leurs consistances, leurs L1loc - continuités et leurs domaines invariants. Le reste du chapitre est dédié à l'existence d'une solution faible dans la classe des fonctions a variations bornées pour l’un de ces modèles. Le but est obtenu en montrant la convergence d'une suite de solutions approchées construites à partir de la méthode de Wave Front Tracking. Le sixième chapitre est consacré à deux modèles macroscopiques sur les réseaux routiers. Le premier est le modèle LWR avec une contrainte mobile et le second est le modèle PT présenté dans le deuxième chapitreThis thesis is devoted to macroscopic traffic flow modelling, which describes traffic flow by variables averaged over multiple vehicles. It mainly focuses on a situation in which the maximum flow of cars is limited at a fixed point along the road. Thanks to such considerations, we can model traffic flow through toll gates or construction sites. From a mathematical point of view we consider systems of hyperbolic conservation laws with constraint condition. Research is based on three macroscopic models, namely Lighthill-Witham-Richards model (LWR), Aw-Rascle-Zhang model (ARZ) and phase transition model (PT). The aim of thesis is to establish the existence and properties of a weak solutions. The thesis consists of 6 chapters and 2 appendices. In the first chapter, we introduce basic ideas of traffic modelling. The second chapter is devoted to a detailed discussion of basic macroscopic traffic flow models. In the third chapter, we describe the LWR model with a local point constraint on the flow. The fourth chapter is devoted to ARZ model with local point constraint on the flow. We prove there the existence of the weak solutions, corresponding to a non-conservative Riemann solver, in the class of functions with bounded variation. The goal is obtained by showing the convergence of a sequence of approximate solutions constructed via the Wave Front Tracking method. In the fifth chapter, we describe two PT models with the local point constraint on the flow. Then we examine their consistency, L1loc-continuity and invariant domains. The remainder of the chapter is devoted to the existence result of a weak solution in the class of function with bounded variation for one of these models with a metastable phase. The goal is obtained by showing the convergence of a sequence of approximate solutions constructed via Wave Front Tracking method. The sixth chapter is devoted to two macroscopic models on road networks. The first is the LWR model with moving constraint on the flow and the second is the PT model introduced in the second chapter
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OUAKNINE, ROGER. "La conservation des aliments par ionisation ; les problemes poses par clostridium botulinum." Strasbourg 1, 1987. http://www.theses.fr/1987STR10748.
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Chung, Heera. "The church defence problem in Conservative politics, 1841-1847." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401142.
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Eersteling, Gjalt. "The effect of managerial ownership on the demand for conservatism." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277250.
Full textAbstract:
In this paper the relation between managerial ownership and conservatism is examined. Managerial ownership decreases agency problems caused by the separation of ownership and control. Managerial ownership increases the time horizon of managers and decreases expropriating behaviour. Conservatism is hypothesized to have the same effect on managers due to the asymmetric timeliness of earnings. This suggest that in firms with lower managerial ownership a demand for conservatism arises to substitute for the alignment function of managerial ownership. This paper test this with two approaches. The first replicates the methodology of previous literature. The findings provide no evidence for substitution between managerial ownership and conservatism. Because the estimators of the first methodology are biased a second method is used applying fixed effects. Consistent with the first approach no supporting evidence is found. However, it finds that firms in the sample have conservative accounting. The main implication of this paper is that rewarding managers with shares is not decreasing their conservative behaviour.
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De-Xing, Kong, and Yao Hui. "Global exact boundary controllability of a class of quasilinear hyperbolic systems of conservation laws II." Universität Potsdam, 2003. http://opus.kobv.de/ubp/volltexte/2008/2656/.
Full textAbstract:
In this paper, by a new constructive method, the authors reprove the global exact boundary controllability of a class of quasilinear hyperbolic systems of conservation laws with linearly degenerate fields. It is shown that the system with nonlinear boundary conditions is globally exactly boundary controllable in the class of piecewise C¹ functions. In particular, the authors give the optimal control time of the system. Finally, a new application is also given.
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Hartmann, Klaas. "Biodiversity conservation and evolutionary models." Thesis, University of Canterbury. Mathematics and Statistics, 2008. http://hdl.handle.net/10092/1776.
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Biodiversity conservation requires a framework for prioritising limited resources to the many endangered species. One such framework that has seen much attention and is considered extensively in this thesis, is the Noah's Ark Problem (NAP). The NAP combines a biodiversity measure (Phylogenetic Diversity; PD) with species survival probabilities and conservation costs. The aim of the NAP is to allocate the limited conservation resources such that the future expected PD is maximised. Obtaining optimal solutions to the NAP is a computationally complex problem to which several efficient algorithms are provided here. An extension to the NAP is also developed which allows uncertainty about the survival probability estimates to be included. Using this extension we show that the NAP is robust to uncertainty in these parameters and that even very poor estimates are beneficial. To justify using or promoting PD, it must produce a significant increase in the amount of biodiversity that is preserved. We show that the increase attainable from the NAP is typically around 20% but may be as high as 150%. An alternative approach to PD and the NAP is to prioritise species using simple species specific indices. The benefit of these indices is that they are easy to calculate, explain and integrate into existing management frameworks. Here we investigate the use of such indices and show that they provide between 60% and 80% of the gains obtainable using PD. To explore the expected behaviours of conservation methods (such as the NAP) a distribution of phylogenetics trees is required. Evolutionary models describe the diversification process by which a single species gives rise to multiple species. Such models induce a probability distribution on trees and can therefore be used to investigate the expected behaviour of conservation methods. Even simple and widely used models, such as the Yule model, remain poorly understood. In this thesis we present some new analytic results and methods for sampling trees from a broad range of evolutionary models. Lastly we introduce a new model that provides a simple biological explanation for a long standing discrepancy between models and trees derived from real data -- the tree balance distribution.
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Swan, George Julius Fraser. "Understanding conservation conflicts surrounding predation and game shooting interests." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/32644.
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Many predatory species cause negative impacts on human interests by threatening game, livestock or human safety. These impacts can create conflicts where stakeholders differ over wildlife management and when one party is perceived to exert their interests at the expense of the other. Finding effective methods to mitigate conservation conflicts requires an interdisciplinary perspective that investigates (i) the reality of the apparent impacts, (ii) the efficacy of any methods intended to remedy them and (iii) the perceptions, motivations and objectives of key stakeholders. In this thesis, I investigated a conservation conflict in the U.K. surrounding predators and game management. I did so with specific reference to the common buzzard Buteo buteo, a species that, due to predation of released pheasants Phasianus colchicus, is both subject to illegal persecution and on- going controversy concerning the licenced selective removal of ‘problem individuals’. I first review the literature to assess the ecological evidence that certain ‘problem individuals’ can be both disproportionately responsible in impacts upon human interests and more likely to reoffend. I show that while there is evidence for these animals across many different taxa, the benefits of their removal can sometimes be short-lived. I highlight possible indirect impacts of selective management and identify it as a potential compromise between different stakeholder groups. Next, I evaluate the performance of Bayesian stable isotope mixing models (BSIMMs) in quantifying the diets of wild animals. By comparing indirect and direct observations of buzzard foraging, I demonstrate that, with the correct selection of trophic discrimination factors, stable isotope analyses can provide a reliable picture of dietary composition that mirrors direct observations. I then apply these mixing models to evaluate the ecological basis of selective removal of ‘problem buzzards’. The results suggest that the consumption by buzzards of released pheasants is not limited to release pens where gamekeepers perceive buzzard predation to be a problem. However, I then show that stable isotope analysis of blood sampled from two of the four buzzards caught inside pens indicates frequent consumption of released pheasants, relative to the rest of the buzzard population. These results suggest that, while some pheasant consumption may go undetected, selecting only buzzards inside pens for removal is likely to target ‘problem birds’. I then investigate buzzard foraging and breeding ecology on land managed for pheasant shooting. I find that buzzards nest at higher density in areas with greater abundances of pheasants and rabbits Oryctolagus cuniculus. However, records of provisioning from nest cameras showed that only rabbits were caught in proportion to their abundance and only rabbit provisioning rate was associated with buzzard productivity. I suggest that the positive relationship between buzzard and pheasant abundance, although seemingly unconnected to pheasant predation, might influence how gamekeepers perceive buzzard impact. Next, I conduct semi-structured interviews on the subject of predator control with 20 gamekeepers across the south of England, to explore the underlying beliefs, norms and information sources that motivate their behaviour. From these interviews, I identify a number of separate, but interconnected, motivations that influence predator control including professional norms, potential penalties, and interpretations of what is ‘natural’. The influences of these motivations are discussed in detail and a conceptual model, incorporating the theory of planned behaviour, is developed. Finally, the key contributions of this thesis are drawn together and discussed in their wider context. Taken together, the results of this thesis illustrate how predator management occurs simultaneously within social and ecological contexts that incorporate the individual attributes of both predators and people. The results of this thesis have direct implications for the management of predators, the representation of stakeholder perspectives and the design of conflict mitigation measures.
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Milisic, Vuk. "Approximation cinétique discrète de problèmes de lois de conservation avec bord." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2001. http://tel.archives-ouvertes.fr/tel-00005164.
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Nous étudions l'approximation cinétique discrète de lois de conservation scalaires quasi-linéaires dans le quart d'espace positif. Cette approximation est obtenue par l'introduction de systèmes de type BGK relaxant la loi scalaire. Nous démontrons la convergence des systèmes semi-linéaires vers la loi scalaire. Nous discrétisons ces modèles pour obtenir une gamme de schémas numériques adaptés au problème avec bord. Dans une troisième partie, nous appliquons ces schémas à un certain nombre de cas test numériques.
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Milišić, Vuk. "Approximation cinétique discrète de problèmes de lois de conservation avec bord." Bordeaux 1, 2001. http://www.theses.fr/2001BOR12449.
Full textAbstract:
Nous étudions l'approximation cinétique discrète de lois de conservation scalaires quasi-linéaires dans le quart d'espace positif. Cette approximation est obtenue par l'introduction de systèmes de type BGK relaxant la loi scalaire. Nous démontrons la convergence des systèmes semi-linéaires vers la loi scalaire. Nous discrétisons ces modèles pour obtenir une gamme de schémas numériques adaptés au problème avec bord. Dans une troisième partie, nous appliquons ces schémas à un certain nombre de cas test numériques.
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SADOUN, BENMEDJEBER DJAMILA. "Le probleme de la conservation des produits lactes : interet des techniques par ionisation." Strasbourg 1, 1987. http://www.theses.fr/1987STR13188.
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Une etude preliminaire realisee en algerie sur la duree de conservation des laits en poudre pour nourrissons, consommes dans ce pays, a mis en evidence une alteration importante de cet aliment apres un an de stockage (degradation des vitamines b1 et c, mais egalement des glucides et des lipides, surprenantes par leur ampleur). Une etude plus detaillee de la fraction lipidique de ces laits, realisee en france mais en ayant choisi des conditions de stockage proches de celles de ghardaia (sud algerien et caracterisees par de fortes amplitudes journalieres de temperature), a permis de confirmer, mais dans une moindre mesure, ces resultats. Dans de telles conditions, une duree de conservation de ces laits de 2 ans parait excessive. Si par contre les poudres de lait sont conservees a des temperatures constantes, aucune alteration des constituants lipidiques n'a ete observee (si ce n'est une diminution normale des teneurs en vitamines a et e), et cela meme lorsque la temperature de stockage est relativement elevee (+30**(o) c). L'interet de l'ionisation comme technique de conservation des laits en poudre semble limitee. Cette etude a cependant permis de montrer qu'a la dose de 1 kgy les proprietes nutritionnelles et organoleptiques de l'aliment etaient conservees et qu'aucun phenomene de rancissement n'etait apparu apres 6 mois de stockage. Cette technique par contre semble plus interessante pour les laits liquides. En ce qui concerne les laits pasteurises, il a ete montre qu'a la dose de 0,25 kgy il etait possible de limiter tres largement la proliferation bacterienne et aussi de doubler la duree de conservation tout en maintenant sensiblement les qualites nutritionnelles et organoleptiques de l'aliment. L'ionisation du lait maternel (a la dose de 0,25 kgy) permet de reduire d'un facteur 10 la contamination bacterienne et de conserver intacts les principaux constituants chimiques, en particulier le facteur antiinfectieux. De ce fait, apres 7 jours de stockage a +4**(o)c, le lait est pratiquement sterile. Un traitement ionisant des laits maternels couple a un traitement thermique tres modere pourrait se reveler fort interessant