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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Genetic and Molecular Analysis of Neurospora Duplications and Duplication-Generating Translocations

Singh, Parmit Kumar January 2010 (has links)
Genetic and Molecular / Neurospora Duplications
2

The influence of reactive oxygen species on human lymphoid cell function in vitro

Cromie, Lillian January 1991 (has links)
No description available.
3

Empirecraft / Empirecraft

Almkvist, Jimmy January 2014 (has links)
I have in my thesis produced a start of a multiplayer, voxel, strategy sandbox game with advanced AI. The world is made out of voxels in the form of blocks that both the players and other units can affect and change. In a world where every block follows the laws of physics for both fluids and physics. The game is designed for several players that fights for controll over land and resources. / Jag har i mitt examensarbete producerat en början av ett flerspelar, voxel, strategi och sandlådespel med avancerad AI. Världen är uppbyggd av voxlar i form av block som både spelaren och andra enheter har möjlighet att påverka och förändra. En värld där varje block följer fysiska lagar för både vätska och fysik. Spelet är designat för flera spelare som strider om områden och resurser med hjälp av sina AI kontrollerade bybor.
4

Resource Management In Celluar And Mobile Opportunistic Networks

Singh, Chandramani Kishore 11 1900 (has links) (PDF)
In this thesis we study several resource management problems in two classes of wireless networks. The thesis is in two parts, the first being concerned with game theoretic approaches for cellular networks, and the second with control theoretic approaches for mobile opportunistic networks. In Part I of the thesis, we first investigate optimal association and power control for the uplink of multichannel multicell cellular networks, in which each channel is used by exactly one base station (BS) (i.e., cell). Users have minimum signal to interference ratio(SINR) requirements and associate with BSs where least transmission powers are required. We formulate the problem as a non-cooperative game among users. We propose a distributed association and power update algorithm, and show its convergence to a Nash equilibrium of the game. We consider network models with discrete mobiles(yielding an atomic congestion game),as well as a continuum of mobiles(yielding a population game). We find that the equilibria need not be Pareto efficient, nor need they be system optimal. To address the lack of system optimality, we propose pricing mechanisms. We show that these prices weakly enforce system optimality in general, and strongly enforce it in special settings. We also show that these mechanisms can be implemented in distributed fashions. Next, we consider the hierarchical problems of user association and BS placement, where BSs may belong to the same(or, cooperating) or to competing service providers. Users transmit with constant power, and associate with base stations that yield better SINRs. We formulate the association problem as a game among users; it determines the cell corresponding to each BS. Some intriguing observations we report are:(i)displacing a BS a little in one direction may result in a displacement of the boundary of the corresponding cell to the opposite direction;(ii)A cell corresponding to a BS may be the union of disconnected sub-cells. We then study the problem of the placement of BSs so as to maximize service providers’ revenues. The service providers need to take into account the mobiles’ behavior that will be induced by the placement decisions. We consider the cases of single frequency band and disjoint frequency bands of operation. We also consider the networks in which BSs employ successive interference cancellation(SIC) decoding. We observe that the BS locations are closer to each other in the competitive case than in the cooperative case, in all scenarios considered. Finally, we study cooperation among cellular service providers. We consider networks in which communications involving different BSs do not interfere. If service providers jointly deploy and pool their resources, such as spectrum and BSs, and agree to serve each others’ customers, their aggregate payoff substantially increases. The potential of such cooperation can, however ,be realized only if the service providers intelligently determine who they would cooperate with, how they would deploy and share their resources, and how they would share the aggregate payoff. We first assume that the service providers can arbitrarily share the aggregate payoff. A rational basis for payoff sharing is imperative for the stability of the coalitions. We study cooperation using the theory of transferable payoff coalitional games. We show that the optimum cooperation strategy, which involves the acquisition of channels, and deployment and allocation of BSs to customers, is the solution of a concave or an integer optimization problem. We then show that the grand coalition is stable, i.e., if all the service providers cooperate, there is an operating point offering each service provider a share that eliminates the possibility of a subset of service providers splitting from the grand coalition; this operating point also maximizes the service providers’ aggregate payoff. These stabilizing payoff shares are computed by solving the dual of the above optimization problem. Moreover, the optimal cooperation strategy and the stabilizing payoff shares can be obtained in polynomial time using distributed computations and limited exchange of confidential information among the service providers. We then extend the analysis to the scenario where service providers may not be able to share their payoffs. We now model cooperation as a nontransferable payoff coalitional game. We again show that there exists a cooperation strategy that leaves no incentive for any subset of service providers to split from the grand coalition. To compute this cooperation strategy and the corresponding payoffs, we relate this game and its core to an exchange market and its equilibrium. Finally, we extend the formulations and the results to the case when customers are also decision makers in coalition formation. In Part II of this thesis, we consider the problem of optimal message forwarding in mobile opportunistic wireless networks. A message originates at a node(source), and has to be delivered to another node (destination). In the network, there are several other nodes that can assist in relaying the message at the expense of additional transmission energies. We study the trade-off between delivery delay and energy consumption. First, we consider mobile opportunistic networks employing two-hop relaying. Because of the intermittent connectivity, the source may not have perfect knowledge of the delivery status at every instant. We formulate the problem as a stochastic control problem with partial information, and study structural properties of the optimal policy. We also propose a simple suboptimal policy. We then compare the performance of the suboptimal policy against that of the optimal control with perfect information. These are bounds on the performance of the proposed policy with partial information. We also discuss a few other related open loop policies. Finally, we investigate the case where a message has to be delivered to several destinations, but we are concerned with delay until a certain fraction of them receive the message. The network employs epidemic relaying. We first assume that, at every instant, all the nodes know the number of relays carrying the packet and the number of destinations that have received the packet. We formulate the problem as a controlled continuous time Markov chain, and derive the optimal forwarding policy. As observed earlier, the intermittent connectivity in the network implies that the nodes may not have the required perfect knowledge of the system state. To address this issue, we then obtain an ODE(i.e., a deterministic fluid) approximation for the optimally controlled Markov chain. This fluid approximation also yields an asymptotically optimal deterministic policy. We evaluate the performance of this policy over finite networks, and demonstrate that this policy performs close to the optimal closed loop policy. We also briefly discuss the case where message forwarding is accomplished via two-hop relaying.
5

Smart Client-Server Protocol and Architecture for Adaptive Multimedia Streaming

Abdullah, Miran Taha 04 June 2018 (has links)
En los últimos años, el consumo de servicios multimedia ha aumentado y se prevé que esta tendencia continúe en un futuro próximo, convirtiendo el tema de la evaluación de la Calidad de la Experiencia (QoE) en un tema muy importante para valorar el servicio de los proveedores. En este sentido, la optimización de la QoE recibe cada vez más atención ya que las soluciones actuales no han tenido en cuenta, la adaptación, la viabilidad, la rentabi-lidad y la fiabilidad. La presente memoria se centra en la caracterización, diseño, desarrollo y evaluación de diferentes aplicaciones multimedia, con el fin de optimizar la QoE. Por tanto, este trabajo investiga la influencia que la infraestructura de redes, las características de los videos y los terminales de los usuarios, presentan en la QoE de los servicios multimedia actuales en Internet. Esta tesis se basa en la investigación exhaustiva de la evaluación subjetiva y objetiva de QoE en redes heterogéneas. Los desafíos y cuestiones relacionados con el estado de la técnica y se discuten en esta disertación. En la primera fase, diseñamos una metodología de prueba para evaluar la QoE en la transmisión de video en directo y a través de plataformas de video bajo demanda en redes Wi-Fi y celulares. A partir de esta fase inicial, propondremos los problemas a investigar y las preguntas para resolver a lo largo de esta disertación. Nuestra metodología hace uso de métricas subjetivas y objetivas para evaluar la QoE percibida por los usuarios finales. Se realiza un conjunto de experimentos en laboratorio donde nuestra metodología de pruebas es aplicada. Los resultados obtenidos se recopilan y analizan para extraer las relaciones entre la Calidad de servicio (QoS) y QoE. A partir de estos resultados, se propone un mapeo de QoS-QoE que permite predecir la QoE. En la siguiente fase de la investigación, desarrollamos los algoritmos de optimización de QoE basados en la administración del sistema de red para redes Wi-Fi y celulares. Los algoritmos usan los parámetros clave que se tuvieron en cuenta para la evaluación de QoE. El objetivo de estos algorit-mos es proporcionar un sistema de gestión flexible para las redes con el ob-jetivo de lograr un equilibrio controlado entre la maximización de QoE y la eficiencia del uso de los recursos. Por último, se diseña el banco de pruebas del sistema para evaluar el rendimiento de las aplicaciones de servicios multimedia genéricos en los diferentes entornos de prueba. El banco de pruebas del sistema se basa en el enfoque de virtualización; usa los recursos compartidos de un hardware fí-sico para virtualizar todos los componentes. El banco de pruebas virtualiza-do proporciona funciones de red virtualizadas para diferentes escenarios, como Internet (las redes de distribución de contenido - CDNs) y redes inalámbricas. Por lo tanto, se adoptan protocolos livianos y mecanismos ágiles en el sistema, para proporcionar un mejor servicio a los usuarios fina-les. Los resultados de QoE son proporcionados a los proveedores de servi-cios de acuerdo con los parámetros que se definen en el proceso de la eva-luación. Como resultado hemos obtenido un sistema que presenta un servi-cio rentable como una forma factible para la evaluación de la prueba. / In recent years, multimedia services consumption has increased and it is expected that this trend will continue in the near future, becoming the evaluation of Quality of Experience (QoE) as a very important issue for assessing the quality of providers' services. In this sense, the optimization of the QoE is progressively receiving much attention considering that current solutions are not based on the adaptation, feasibility, cost-effectiveness, and reliability. The present dissertation is focused on the characterization, design, development and evaluation of different multimedia applications aimed to optimize the QoE. Therefore, this work investigates the influence that the networks infrastructure, the videos' characteristics and the users' terminals present on QoE of the current Internet multimedia services. The work is based on a comprehensive research of subjective and objective assessments in heterogeneous networks. Challenges and research questions related to the state of the art are discussed in this dissertation. In the first phase of this dissertation, we design a test methodology for assessing QoE of live video streaming and video on demand platforms to be transmitted over Wi-Fi and cellular networks. From this initial step, we will propound the related research issues and questions to solve this dissertation. Our methodology considers the use of subjective and objective metrics to evaluate the QoE perceived by end-users. A set of laboratory experiments is conducted where our proposed methodology is applied. The obtained results are gathered and analyzed to extract the relations between Quality of Service (QoS) and QoE. From the results, we propose a QoS-QoE mapping which allows predicting QoE. In the next phase of the research, we develop QoE-optimization algorithms based on network system management for Wi-Fi and cellular networks. The algorithms use the key parameters that were taken into account for QoE assessment. The goal of these algorithms is to provide a flexible management system for the networks in order to achieve the desirable trade-off between QoE maximization and resource usage efficiency. Lastly, the system testbed is designed in order to evaluate the performance of generic multimedia services applications for the different environments under test. The system testbed is based on virtualization approach; it uses the shared resources of a physical hardware to virtualize all components. The virtualized testbed provides virtualized network functions for the different scenarios such as the Internet (Content Delivery Networks - CDNs) and wireless networks. Therefore, lightweight protocols and agile mechanisms are adopted in the system to provide enhanced service to end-users. The QoE results are reported to the service providers according to the parameters defined in the evaluation process. As a result, we have obtained a cost-effective system, which is considered as a feasible way for test evaluation. / En els últims anys, el consum de serveis multimèdia ha augmentat i es preveu que aquesta tendència continue en un futur pròxim, convertitnt el tema de l'avaluació de la Qualitat d'Experiència (QoE) una tasca molt im-portant per a valorar el servei dels proveïdors. En aquest sentit, l'optimització de la QoE rep cada vegada més atenció degut a que les solucions actuals no tenen en compte, l'adaptació, la viabilitat, el rendiment i la fiabilitat. La present memòria se centra en la caracterització, disseny, desenvolupament i avaluació de diferents aplicacions multimèdia, amb la finalitat d'optimitzar la QoE. Per tant, aquest treball investiga la influència que la infraestructura de les xarxes, les característiques dels videos i els terminals dels usuaris tenen sobre la QoE dels serveis multimèdia actuals d'Iinternet. Aquesta tesi es basa en una recerca exhaustiva de l'avaluació subjectiva i objectiva de QoE en xarxes heterogènies. Els desafiaments i preguntes relacionats amb l'estat de la tècnica es discuteixen en aquesta dissertació. En la primera fase, dissenyem la metodologia de prova per a avaluar la QoE de transmissió de video en directe i de plataformes de video baix demanda en xarxes Wi-Fi i cel·lulars. A partir d'aquest primer pas, proposem els problemes de recerca relacionats i les preguntes a resoldre a través d'a-questa tesi. La nostra metodologia fa ús de mètriques subjectives i objecti-ves per a avaluar la QoE dels usuaris finals. Es realitzen un conjunt d'expe-riments en laboratori on s'aplica la nostra metodología. Els resultats obtin-guts es recopilen i analitzen per a extraure les relacions entre la QoS i la QoE. A partir d'aquests resultats, esproposa un mapatge de QoS-QoE que ens permetrà predir la QoE. En la següent fase de la recerca, desenvolupem els algoritmes d'optimi-tzació de la QoE per a l'administració de xarxes Wi-Fi i cel·lulars. Els algo-ritmes utilitzen els paràmetres clau que es van tenir en compte per a l'ava-luació de QoE. L'objectiu d'aquests algoritmes és proporcionar un sistema de gestió flexible per ales xarxes que permetrá aconseguir un equilibri con-trolat entre la maximització de la QoE i l'us eficient dels recursos. Finalment, el banc de proves del sistema està dissenyat per a avaluar el rendiment de les aplicacions de serveis multimèdia genèrics en els diferents entorns de prova. El banc de proves del sistema es basa en l'enfocament de virtualització; usa els recursos compartits d'un equip físic que virtualitza tots els components. El banc de proves virtualitzat proporciona les funcions de xarxa virtualitzades per a diferents escenaris, com Internet (les xarxes de distribució de continguts - CDNs) i xarxes sense fils. Per tant, s'adopten protocols lleugers i mecanismes àgils en el sistema per a proporcionar un millor servei als usuaris finals. Els resultats de QoE son proporcionats als proveïdors de serveis d'acord amb els paràmetres que es defineixen en el procés de l'avaluació. Com a resultat, hem obtés un sistema que presenta un servei rendible i com a viable per a l'avaluació de la prova. / Abdullah, MT. (2018). Smart Client-Server Protocol and Architecture for Adaptive Multimedia Streaming [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/103324 / TESIS

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