Дисертації: "Psp system"

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Wallart, Lisa. "Caractérisation du système BAC : vers l'hypothèse d'un système Psp original chez Pseudomonas aeruginosa." Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMR119.

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L’émergence et la propagation des bactéries multirésistantes aux antibiotiques est devenue une problématique majeure de santé publique. En particulier, P. aeruginosa fait partie des pathogènes opportunistes humains pour lesquels il devient urgent de développer de nouvelles stratégies thérapeutiques. P. aeruginosa est un germe qui cible préférentiellement les individus dont le système immunitaire est affaibli. Ainsi, les patients atteints de mucoviscidose, d’un cancer, du SIDA, ou hospitalisés sur une longue durée sont des sujets à haut risque d’infection à P. aeruginosa. Chez ces patients, ces infections sont associées à une forte morbidité et mortalité, en raison de la persistance et de la résistance des bactéries colonisant les tissus de l’hôte sous forme de biofilms.Mes travaux de thèse s’inscrivent dans l’objectif de découvrir de nouvelles cibles pour le design de futurs traitements novateurs. Je décris dans ce manuscrit les derniers éléments de caractérisation du système BAC (pour « Biofilm Associated Cluster »), qui nous permettent de l’envisager comme un système Psp original. Ce système est ainsi constitué de 6 protéines codées par l’opéron bacABCDEF. L’expression de cet opéron se ferait en réponse à des stimuli et serait sous la dépendance du facteur sigma σ54 et du système à deux composants Gac/Rsm. La structure de BacA (protéine présentant un domaine DUF2170), nouvellement élucidée, est homologue à celle de protéines chaperonnes du SST3 suggérant que BacA serait impliquée dans la régulation de l’expression de bacABCDEF. La protéine BacB est quant à elle un homologue structural des protéines PspA et Vipp1 supposant que le système BAC serait impliqué dans la protection membranaire sous l’action d’un stress extra-cytoplasmique encore inconnu. La protéine BacD semble être une flotilline, protéine « échafaudage » connue pour résider dans les microdomaines fonctionnels, aussi appelés lipid rafts The emergence and spread of bacteria that are multi-resistant to antibiotics has become a real public health concern. In particular, P. aeruginosa is one of the major human opportunistic pathogens for which it is urgent to develop new therapeutic strategies. P. aeruginosa is a microorganism that preferentially targets immuno-compromised individuals. Thus, patients suffering from cystic fibrosis, cancer, AIDS, or hospitalized for a long period are subjects at high risk of P. aeruginosa infection. In these patients, these infections are associated with high morbidity and mortality, due to the persistence and resistance of bacteria colonizing host tissues most often within biofilms.My thesis work is part of the objective of discovering new targets for the design of future innovative treatments. In this manuscript I describe the latest elements of characterization of the BAC system (for “Biofilm Associated Cluster”), which allow us to consider it as an original Psp system. This system is thus made up of 6 proteins encoded by the bacABCDEF operon. The expression of this operon would occur in response to stimuli and would be dependent on the sigma factor σ54 and the Gac/Rsm two-components system. The structure of BacA (protein presenting a DUF2170 domain), newly elucidated, is homologous to that of T3SS chaperone proteins suggesting that BacA is involved in the regulation of bacABCDEF expression. The BacB protein is a structural homolog of the PspA and Vipp1 proteins, suggesting that the BAC system is involved in membrane protection under the action of a yet unknown extra-cytoplasmic stress. The BacD protein appears to be a flotillin, a “scaffolding” protein known to reside in functional membrane microdomains, also called lipid rafts

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Kreis, Eri Sato. "ANA-PSp: um sistema computacional para análise aeroelástica de pontes suspensas por modelos matemáticos reduzidos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-31032008-151227/.

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As características arquitetônicas e o desempenho estrutural de pontes suspensas, estaiadas ou pênseis, têm determinado a sua crescente utilização em obras de arte destinadas a vencer grandes vãos. Essa utilização crescente que ocorreu no mundo nas últimas décadas se repete agora nos últimos anos no país. Várias dessas obras estão em execução e em projeto. Um dos aspectos relevantes na análise estrutural das pontes suspensas é o de seu comportamento quando submetidas à ação do vento. Apresenta-se o sistema computacional ANA-PSp desenvolvido especialmente para o estudo do movimento de tabuleiros de pontes suspensas sujeitas a esforços aeroelásticos e aerodinâmicos. Esse sistema computacional formado por um conjunto de subsistemas, é elaborado para a análise aeroelástica de pontes suspensas sob a ação de vento e permite análises paramétricas extensas dos fenômenos de drapejamento (flutter) e de martelamento (buffeting). A discretização da estrutura é efetuada pelo método dos elementos finitos e a redução dos graus de liberdade é realizada por superposição modal com modos selecionados que melhor descrevem os movimentos do tabuleiro. Utiliza-se modelo matemático reduzido para a análise multimodal no domínio do tempo e da freqüência. A velocidade crítica ou velocidade de drapejamento é determinada por procedimento de autovalores complexos com a obtenção de freqüências e taxas de amortecimentos modais para várias velocidades do vento. Adicionalmente, o fenômeno do drapejamento é estudado por séries temporais de respostas de coordenadas generalizadas e de deslocamentos selecionados e por análise espectral dessas séries temporais, que permitem a verificação das características de vibração do tabuleiro da ponte no domínio da freqüência. O estudo do fenômeno de martelamento considera esforços aeroelásticos determinísticos e esforços aerodinâmicos estocásticos e apresentam-se resultados em espectros de potência de deslocamentos e em desvios padrão de deslocamentos ao longo do tabuleiro. Para validar o sistema ANA-PSp, apresentam-se estudos de caso para a ponte estaiada da Normandia, para a ponte pênsil colapsada de Tacoma Narrows e para a ponte estaiada projetada, mas não executada, sobre o Rio Tietê e localizada na extremidade do complexo viário Jacu-Pêssego. The architectonic characteristics and the structural performance of suspension bridges and cable-stayed bridges have determined their growing use on large span bridges. This growing usage, which has occurred world-wide during the last decades, is now being repeated in Brazil during the last few years. Several such bridges are presently either undergoing construction or being designed. One of the outstanding aspects in the structural analysis of suspension bridges is their behavior under wind action. This paper presents the computer system ANA-PSp, specially developed for studying the movement of suspended bridge decks under aeroelastic and aerodynamic forces. This computer system is formed by a group of subsystems and is created for aeroelastic analysis of suspended bridges under wind action. It allows extended parametric analyses of the flutter and the buffeting phenomena. Structural discretization is done by the finite element method and the reduction of degrees of freedom is obtained by modal superposition of the selected modes which best describe the deck movements. A reduced mathematical model is used for the multimodal analysis in the time and frequency domains. Critical velocity or flutter velocity is determined by a procedure of complex eigenvalues which obtains frequencies and damping ratios for different wind speeds. Additionally, the flutter phenomenon is studied by temporal series of answers to generalized coordinate responses and of selected displacements by spectral analysis of such temporal series, which allow us to verify the characteristics of the vibrations of the bridge deck in the frequency domain. The study of the buffeting phenomenon considers deterministic aeroelastic and stochastic aerodynamic forces. The paper presents results in displacement power spectra and in the standard deviation of displacements along the deck. In order to validate system ANA-PSp, case studies are presented for the cable-stayed Ponte de Normandie in Le Havre (France), for the collapsed suspension bridge on Tacoma Narrows and for the cable-stayed bridge, already designed but not built, on Tietê River, located at one end of the highway complex Jacu-Pêssego (São Paulo, SP, Brazil).

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Banelis, Andrius. "Kardiovaskulinės reabilitacijos pacientų informacinės sistemos kūrimas ir tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050525_154503-81122.

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Project dedicated for the united information base creation and storage of the cardiovascular reabilitation patients. Using this reabilitation it is necessary to watch the test results of the patient, analyse and systematize them. Besides collected information can be used for the later treatment of the patient. Thus having a huge storage it is hard to find record if it is on paper, in that case invoking information technology, which will ease storage of the big information quantity, quick it processing and analysis. Besides selection of that organization bussines reorganization will sharply increase workers work efficiency. Nowadays test equipment deliver results which a specialist have to transform into understandable form that these results could be used for analysis about patient health status.

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Duan, Daliang. "Epsp : un environnement support de genie logiciel base sur l'approche du prototypage de systeme et sur le langage prolog." Toulouse 3, 1987. http://www.theses.fr/1987TOU30223.

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Epsp offre une interface informelle pour etablir un prototype de systeme en prolog (psp). Cette interface a essentiellement pour but de rendre prolog le plus transparent possible a l'utilisateur. Epsp utilise une specification executable comme prototype, ecrit en prolog. Epsp permet le raffinage a partir de la specification par tranformation successive du psp. Epsp est constitue de plusieurs outils logiciels. Il est developpe en prolo nongp et pascal

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Gill, Martin L. "Combining MAS and P2P systems : the Agent Trees Multi-Agent System (ATMAS)." Thesis, University of Stirling, 2005. http://hdl.handle.net/1893/108.

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The seamless retrieval of information distributed across networks has been one of the key goals of many systems. Early solutions involved the use of single static agents which would retrieve the unfiltered data and then process it. However, this was deemed costly and inefficient in terms of the bandwidth since complete files need to be downloaded when only a single value is often all that is required. As a result, mobile agents were developed to filter the data in situ before returning it to the user. However, mobile agents have their own associated problems, namely security and control. The Agent Trees Multi-Agent System (AT-MAS) has been developed to provide the remote processing and filtering capabilities but without the need for mobile code. It is implemented as a Peer to Peer (P2P) network of static intelligent cooperating agents, each of which control one or more data sources. This dissertation describes the two key technologies have directly influenced the design of ATMAS, Peer-to-Peer (P2P) systems and Multi-Agent Systems (MAS). P2P systems are conceptually simple, but limited in power, whereas MAS are significantly more complex but correspondingly more powerful. The resulting system exhibits the power of traditional MAS systems while retaining the simplicity of P2P systems. The dissertation describes the system in detail and analyses its performance.

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Mészáros, István. "Distributed P2P Data Backup System." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2013. http://www.nusl.cz/ntk/nusl-236378.

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Tato diplomová práce představuje model a prototyp kooperativního distributivního systému zálohování dat založeném na P2P komunikační síti. Návrh systému umožňuje uživatelům přispět svým lokálním volným místem na disku do systému výměnou za spolehlivé úložiště jejich dat u jiných uživatelů. Představené řešení se snaží splnit požadavky uživatelů na ukládání dat, zároveň však také řeší, jak se vypořádat s mírou nepředvídatelnosti uživatelů ohledně poskytování volného místa. To je prováděno dvěma způsoby - využitím Reed - Solomon kódů a zároveň také tím, že poskytuje možnost nastavení parametrů dostupnosti. Jedním z těchto parametrů je časový rozvrh, který značí, kdy uživatel může nabídnout předvídatelný přínos do systému. Druhý parametr se týká spolehlivosti konkrétního uživatele v rámci jeho slíbeného časového úseku. Systém je schopen najít synchronizaci ukládaných dat na základě těchto parametrů. Práce se zaměřuje rovněž na řešení zabezpečení systému proti širšímu spektru možných útoků. Hlavním cílem je publikovat koncept a prototyp. Jelikož se jedná o relativně nové řešení, je důležitá také zpětná vazba od široké veřejnosti, která může produkt používat. Právě jejich komentáře a připomínky jsou podnětem pro další vývoj systému.

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Juříček, Petr. "ANALÝZA VYUŽITÍ PPP PROJEKTŮ PŘI ZAJIŠTĚNÍ RESTRIKTIVNÍCH FUNKCÍ STÁTU." Doctoral thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-199394.

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This dissertation examines the possibility of private sector involvement in financing the Czech prison system. In the Western World, this form of provision has now become common practice. The paper explores the possibilities of both full and partial participation of the private sector in the provision of one of the restrictive services that in the Czech Republic are delivered exclusively by the state. The theoretical section discusses different alternatives regarding the financial provision through public-private partnerships (PPP projects). These are viewed as part of a wider and comprehensive area of public contracting. Due to the absence of this form of provision in the Czech Republic, all information regarding this alternative has been sourced from foreign prison systems where private forms of prison service have a long tradition (e.g. the concept of privatization by Charles Logan). The findings are then applied and compared with the foundations of the Czech prison system (whose primary role is security and specialist provision) with respect to the economic efficiency of the whole system. A case study is presented which outlines different projections regarding operating costs in a sample of three American prisons with the aim to compare the estimated and real costs depending on the form of provision, i.e. by state or through private management. The research section of the dissertation uses data from the Feasibility study of building a private prison in the Czech Republic. Using calculated values, CBA analysis is employed to evaluate three possible alternatives of financing the construction of a private prison. To evaluate the costs, the following methods were used: the Public Sector Comparator, the DBFO model (Design -- Build -- Finance -- Organize) and the BOT model (Build -- Organize -- Transfer) which primarily utilizes the work potential of prisoners in relation to the increase of return on investment in penitentiary provision. The results of the BOT model showed that the mere existence of participation of a private partner in the Czech prison system can be beneficial as it introduces an important element of competition and basic principles of market economy into the system. However, greater efficiency can only be achieved provided that a more efficient system of settlement of outstanding debts of prisoners is employed. This requires a more sophisticated policy for employing prisoners.

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Weragama, Dinesha Samanthi. "Intelligent tutoring system for learning PHP." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/63202/1/Dinesha%20Samanthi_Weragama_Thesis.pdf.

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This thesis investigates the possibility of using an adaptive tutoring system for beginning programming students. The work involved, designing, developing and evaluating such a system and showing that it was effective in increasing the students’ test scores. In doing so, Artificial Intelligence techniques were used to analyse PHP programs written by students and to provide feedback based on any specific errors made by them. Methods were also included to provide students with the next best exercise to suit their particular level of knowledge.

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Wächter, Silke. "Pesso-Psychotherapie (PBSP) : eine Evaluationsstudie zur Wirksamkeit /." München : CIP-Medien, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=9783932096679.

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Chatzidrossos, Ilias. "P2P Live Video Streaming." Licentiate thesis, KTH, Communication Networks, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12373.

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The ever increasing demand for video content directed the focus of researchfrom traditional server-based schemes to peer-to-peer systems for videodelivery. In such systems, video data is delivered to the users by utilizing theresources of the users themselves, leading to a potentially scalable solution.Users connect to each other, forming a p2p overlay network on top of theInternet and exchange the video segments among themselves. The performanceof a p2p system is characterized by its capability to deliver the videocontent to all peers without errors and with the smallest possible delay. Thisconstitutes a challenge since peers dynamically join and leave the overlay andalso contribute different amounts of resources to the system.The contribution of this thesis lies in two areas. The first area is theperformance evaluation of the most prominent p2p streaming architectures.We study the streaming quality in multiple-tree-based systems. We derivemodels to evaluate the stability of a multiple tree overlay in dynamic scenariosand the efficiency of the data distribution over the multiple trees. Then, westudy the data propagation in mesh-based overlays. We develop a generalframework for the evaluation of forwarding algorithms in such overlays anduse this framework to evaluate the performance of four different algorithms.The second area of the thesis is a study of streaming in heterogeneous p2poverlays. The streaming quality depends on the aggregate resources that peerscontribute to the system: low average contribution leads to low streamingquality. Therefore, maintaining high streaming quality requires mechanismsthat either prohibit non-contributing peers or encourage contribution. In thisthesis we investigate both approaches. For the former, we derive a model tocapture the evolution of available capacity in an overlay and propose simpleadmission control mechanisms to avoid capacity drainage. For the latter, inour last work, we propose a novel incentive mechanism that maximizes thestreaming quality in an overlay by encouraging highly contributing peers tooffer more of their resources. QC 20100506

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Martins, Vidal. "Data Replication in P2P Systems." Phd thesis, Université de Nantes, 2007. http://tel.archives-ouvertes.fr/tel-00481828.

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Cette thèse porte sur la réplication de données dans les systèmes pair-à-pair (P2P). Elle est motivée par l'importance croissante des applications de collaboration répartie et leurs besoins spécifiques en termes de réplication de données, cohérence de données, passage à l'échelle, et haute disponibilité. En employant comme exemple un Wiki P2P, nous montrons que les besoins de réplication pour les applications collaborative sont : haut niveau d'autonomie, réplication multi-maître, détection et résolution de conflit basé sur sémantique, cohérence éventuelle parmi des répliques, hypothèses faibles de réseau, et indépendance des types de données. Bien que la réplication optimiste adresse la plupart de ces besoins, les solutions existantes sont peu applicables aux réseaux P2P puisqu'elles sont centralisées ou ne tiennent pas compte des limitations de réseau. D'autre part, les solutions existantes de réplication P2P ne répondent pas à toutes ces exigences simultanément. En particulier, aucune d'elles ne fournit la cohérence éventuelle parmi des répliques avec des hypothèses faibles de réseau. Cette thèse vise à fournir une solution de réconciliation fortement disponible et qui passe à l'échelle pour des applications de collaboration P2P en développant un protocole de réconciliation qui assure la cohérence éventuelle parmi des répliques et tient compte des coûts d'accès aux données. Cet objectif est accompli en cinq étapes. D'abord, nous présentons des solutions existantes pour la réplication optimiste et des stratégies de réplication P2P et nous analysons leurs avantages et inconvénients. Cette analyse nous permet d'identifier les fonctionnalités et les propriétés que notre solution doit fournir. Dans une deuxième étape, nous concevons un service de réplication pour le système APPA (en anglais, Atlas Peer-to-Peer Architecture). Troisièmement, nous élaborons un algorithme pour la réconciliation sémantique répartie appelée DSR, qui peut être exécuté dans différents environnements répartis (par ex. grappe, grille, ou P2P). Dans une quatrième étape, nous faisons évoluer DSR en protocole de réconciliation pour des réseaux P2P appelé P2P-reconciler. Finalement, la cinquième étape produit une nouvelle version de P2P-reconciler, appelée P2P-reconciler-TA, qui exploite les réseaux P2P conscients de leur topologie (en anglais, topology-aware) afin d'améliorer les performances de la réconciliation. Nous avons validé nos solutions et évalué leurs performances par l'expérimentation et la simulation. Les résultats ont montré que notre solution de réplication apporte haute disponibilité, excellent passage à l'échelle, avec des performances acceptables et surcharge limitée.

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Hayek, Rabab. "Summary management in P2P systems." Nantes, 2009. http://www.theses.fr/2009NANT2066.

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Le but de cette thèse est de contribuer au développement des techniques de localisation et de description de données dans des environnements P2P. Au niveau de la couche application, nous nous concentrons sur l’exploitatoin des sémantiques qui peuvent être capturées à partir des données partagées. Ces sémantiques peuvent améliorer l’efficacité de recherche, ainsi que permettre des requêtes complexes. A cet effet, nous présentons une technique originale d’indexation de données dans les systèmes P2P qui se base sur les résumés linguistiques. Nos résumés sont des vues synthétiques et multidimensionnelles qui supportent la localisation des données pertinentes en se basant sur leur contenu. Plus intéressant, ils fournissent des représentations intelligibles de données, qui peuvent renvoyer des réponses approximatives à des requêtes d’utilisateur. Au niveau de la couche réseau P2P, nous nous concentrons sur l’exploitation des caractéristiques de la topologie, à savoir les caractéristiques de leur regroupement (clustering). Des informations sur le clustering du réseau P2P peuvent être utilisées pour réduire le trafic de réseau produit par le mécanisme de flooding. Ceci permet d’améliorer l’exécution des systèmes P2P, indépendamment de l’emploi des index de données à la couche application, puisque le mécanisme de flooding représente toujours un bloc constitutif fondamental des systèmes non structurés P2P. Dans cette thèse, nous présentons un bref état de l’art sur les systèmes P2P de partage de données P2P et nous nous concentrons sur l’évolution des systèmes simples de partages des fichiers vers des systèmes de gestion des données. En second lieu, nous proposons une solution pour la gestion des résumés de données dans des systèmes P2P. Nous définissons un modèle approprié et des techniques efficaces pour la création et la mise à jour des résumés. Nous discutons également le traitement des requêtes dans le cadre des résumés. Troisièmement, nous proposons une technique de recherche basée sur clustering implémentée au dessus d’un protocole de custering selon la connectivité des noeuds. Nous nous concentrons sur la réduction des messages de requêtes redondants qui surchargent inutilement le système. Nous avons validé nos solutions par la simulation et les résultats montrent une bonne performance The goal of this thesis is to contribute to the development of data localization and summarization techniques in P2P environments. At the application layer, we focus on exploiting the semantics that can be captured from the shared data. These semantics can improve the search efficiency, and allow for more query facilities. To this end, we introduce a novel data indexing technique into P2P systems that relies on linguistic summarization. Our summaries are synthetic, multidimensional views that support locating relevant data based on their content. More interestingly, they provide intelligible data representations which may return approximate answers for user queries. At the P2P network layer, we focus on exploiting the characteristics of the overlay topology, namely its clustering features, in order to reduce the traffic overhead generated by flooding-based mechanisms. This allows to improve the performance of P2P systems, irrespective of the employment of techniques relying on data semantics at the application layer. To this end, we define a cluster-based search technique which is implemented over a connectivity-based clustering protocol. A connectivity-based clustering protocol aims to discover the natural organization of nodes, based on their connectivity. Thus, it delimits the boundaries of non-overlapping subgraphs (i. E. Clusters) which are loosely connected, and in which nodes are highly connected. In this thesis, we first survey P2P data sharing systems. We focus on the evolution from simple file-sharing systems with limited functionalities, to Peer Data Management Systems (PDMSs) that support advanced applications with more sophisticated data management techniques. Second, we propose a solution for managing linguistic summaries in P2P systems. We define an appropriate summary model and efficient techniques for summary creation and maintenance. We also discuss query processing in the context of summaries. Third, we propose a cluster-based search technique on top of existing connectivity-based clustering protocols. We focus on reducing redundant query messages which unnecessarily overload the system. We validated our solutions through simulation and the results show good performance

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Jawad, Mohamed. "Data privacy in P2P Systems." Nantes, 2011. http://www.theses.fr/2011NANT2020.

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Les communautés en ligne pair-a-pair (P2P), comme les communautés professionnelles (p. Ex. , médicales ou de recherche) deviennent de plus en plus populaires a cause de l’augmentation des besoins du partage de données. Alors que les environnements P2P offrent des caractéristiques intéressantes (p. Ex. , passage a l’échelle, disponibilité, dynamicité), leurs garanties en termes de protection des données sensibles sont limitées. Ils peuvent être considérés comme hostiles car les données publiées peuvent être consultées par tous les pairs (potentiellement malicieux) et utilisées pour tout (p. Ex. , pour le commerce illicite ou tout simplement pour des activités contre les préférences personnelles ou éthiques du propriétaire des données). Cette thèse propose un service qui permet le partage de données sensibles dans les systèmes P2P, tout en assurant leur confidentialité. La première contribution est l’analyse des techniques existant pour la confidentialité de données dans les architectures P2P. La deuxième contribution est un modèle de confidentialité, nomme PriMod, qui permet aux propriétaires de données de spécifier leurs préférences de confidentialité dans de politiques de confidentialité et d’attacher ces politiques a leurs données sensibles. La troisième contribution est le développement de PriServ, un service de confidentialité, base sur une DHT qui met en oeuvre PriMod afin de prévenir la violation de la confidentialité de données. Entre autres, PriServ utilise de techniques de confiance pour prédire le comportement des pairs Online peer-to-peer (P2P) communities such as professional ones (e. G. , medical or research communities) are becoming popular due to increasing needs on data sharing. P2P environments offer valuable characteristics but limited guarantees when sharing sensitive data. They can be considered as hostile because data can be accessed by everyone (by potentially malicious peers) and used for everything (e. G. , for marketing or for activities against the owner’s preferences or ethics). This thesis proposes a privacy service that allows sharing sensitive data in P2P systems while protecting their privacy. The first contribution consists on analyzing existing techniques for data privacy in P2P architectures. The second contribution is a privacy model for P2P systems named PriMod which allows data owners to specify their privacy preferences in privacy policies and to associate them with their data. The third contribution is the development of PriServ, a privacy service located on top of DHT-based P2P systems which implements PriMod to prevent data privacy violations. Among others, PriServ uses trust techniques to predict peers behavior

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Hubený, Lukáš. "Porovnání technologií pro tvorbu informačních systémů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217486.

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The topic of this master thesis is a comparison of the technologies for information systems creation. There are compared four fundamental technologies: Php, ASP.NET, JSP and Perl. The comparison of these technologies have two main stages: The first stage is mostly theoretical and demonstrate theoretical advantages and drawbacks of these platforms. The second stage demonstrates on some short examples advantages of platforms during information systems programming. Co-operation with database systems is compared too.

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Wächter, Silke. "Pesso-Psychotherapie (PBSP) eine Evaluationsstudie zur Wirksamkeit." München CIP-Medien, 2008. http://d-nb.info/992784697/04.

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16

Houlné, Guy. "Structure et expression des genes codant pour les apoproteines des antennes collectrices de photons ps2 et ps1 chez euglena gracilis." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13169.

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17

Gronau, Norbert, and Simone Schmid. "Martüberblick : Konfiguratoren in ERP-/PPS-Systemen." Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2006/682/.

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Die Orientierung am Kunden und dessen individuellen Wünschen ist heutzutage von großer Bedeutung. Mit Hilfe eines Produktkonfigurationssystems ist es möglich, Produkte nach bestimmten Regeln aus bestimmten Bauteilen virtuell zu entwickeln [1] und somit die gewünschten Leistungsmerkmale der Kunden auf ihre Durchführbarkeit hin zu überprüfen. In der vorliegenden Marktuntersuchung wurden die Leistungsfähigkeit von Konfiguratoren sowohl in ERP-/PPS-Systemen als auch als Stand-alone-Lösung untersucht und darauf überprüft, inwiefern sie zur Bewältigung komplexer und variantenreicher Produktgestaltungsaufgaben geeignet sind. Market research : configurators in ERP-/PPS-Systems: Today customer orientation is of great importance. With the help of a product-configuration-system it is possible to develop products virtually under specific rules and therefore to prove the customer capability characteristics for their practicability. In the present market research the capability of configurators in ERP-/PPS-systems as well as in stand-alone-solutions were checked and it was tested to what extend they are suitable to cope with complex product implementation. ------- © GITO mbH Berlin

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18

Heidrich, Eyleen Sabine [Verfasser]. "Aktivierung des Psp-Systems durch TatA-induzierten Membranstress in Escherichia coli / Eyleen Sabine Heidrich." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1204458421/34.

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Mellberg, Simon. "Omarbetning utav PHP-skript och databasintegritet." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-167253.

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Den här rapporten beskriver det arbete som är utfört hos Techsam AB för att eliminera eller åtminstone minska riskerna att data går förlorad eller förändras. Projektets syfte är att redogöra problemområden och åtgärda nuvarande system. Problemområden är alla ställen det görs en insättning eller en uppdatering utav databasen. Projektets huvudsakliga uppgift är att utveckla det system som redan finns driftsatt. Databasintegritet är en viktig punkt i projektet, och det finns större möjligheter att kontrollera data desto längre mot slutet produkten kommer. Därmed har andra lösningar införts i början utav produktionen. De lösningarna är visuella stöd och varningar som hjälper att göra rätt beslut. Eftersom systemet endast används \textit{''in-house''} finns det inga krav på utseende eller säkerhet utifrån, utan kraven ligger kring funktion och integritet mot databasen. Utseendet har inte påverkats. This report describes the work that is done at Techsam AB to eliminate or at least lower the risk of dataloss or change of data. The project purpose is to uncover problematic areas and fix these issues. Problematic areas are everywhere where data is sent och updated in the database. The projects main assignment is to update the system that is already in use. Databaseintegrity is an important topic in this article, and there the possibilities to check data are greater the further down the line you get. Therefore other solutions have been used to aid the user. Those solutions are visual aids and warnings to help make correct decisions. Since the system is only used in-house there are no demands on the apperance nor security outwards, the demands are on the function and integrity towards the database. The appereance have not been altered.

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Steude, Volker Werners Brigitte. "PPS-Systeme auf Basis von Simulation /." Lohmar : Eul, 2003. http://www.gbv.de/dms/zbw/363288775.pdf.

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Filali, Imen. "Improving resource discovery in P2P systems." Nice, 2011. http://www.theses.fr/2011NICE4012.

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Le modèle de communication pair-à-pair a beaucoup attiré l’attention dans les dernières années car il est considéré comme un paradigme puissant pour déployer et exécuter des applications distribuées à grande échelle. Dans ce contexte, le problème de découverte de ressources, c’est-à-dire la recherche d’une ressource donnée répondant aux besoins de l’application constitue un aspect critique dans les systèmes pair-à-pair. Cette thèse se concentre sur la recherche de ressources dans les systèmes pair-à-pair non structurés ainsi que structurés. Dans la première partie de cette thèse, nous proposons un algorithme de découverte de ressources dans un environnement non structuré qui ajuste l’horizon de la requête dynamiquement dans le but de retrouver les ressources demandées d’une manière efficace. La deuxième partie porte sur la conception et l’implémentation d’une architecture pair-à-pair hiérarchique ayant pour but le stockage et la recherche de ressources sémantiques à grande échelle. Cette infrastructure combine le modèle pair-à-pair au niveau de l’architecture elle même et le modèle RDF au niveau de la représentation des données The Peer-to-Peer (P2P) communication model has drawn much attention in the last few years and has been emerged as a powerful paradigm to build large scale distributed applications. Resource discovery constitutes a critical aspect of P2P systems; it involves the matching of the user’s application requirements to available resources. The thesis focuses on the resource discovery in P2P systems encompassing unstructured and structured P2P overlays. In the first part of this work, we have concentrated on resource discovery in unstructured P2P systems. We have proposed and evaluated a novel algorithm for resource location in unstructured P2P networks that dynamically adjust the query horizon in order to efficiently locate the required resources. The second part of the thesis deals with the design and the implementation of a hierarchical P2P semantic space infrastructure aiming at the distributed storage and retrieval of the semantic data at large scale. This infrastructure combines the strengths of both P2P paradigm at the architectural level and the Resource Description Framework (RDF) data model at the knowledge representation level. While the P2P communication model addresses the system complexity by allowing flexible and decentralized resource storage and processing, the semantic web technologies, on the other hand, address the problem of information complexity by providing advanced support for data presentation and querying

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Gonçalves, Joana Margarida Dias de Bragança. "Peer-level characterization of P2P systems." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2182.

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Havlíček, Jiří. "Systém pro vedení bakalářských a diplomových prací." Master's thesis, Vysoká škola ekonomická v Praze, 2014. http://www.nusl.cz/ntk/nusl-193936.

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This thesis deals with the analysis, design and final implementation of information system for thesis management. In the introduction the theoretical background is defined and avail-able technologies are identified and later practically used within the implementation. Fur-ther, the functional and non-functional demands are identified, use case scenarios defined and later on the system is designed and implemented. The requirements are defined based on the universal use within the use cases of the University of Economics in Prague. Within the last part, a user manual can be found.

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Kormaňák, Tomáš. "Jednoduchý informační systém pro základní a střední školy." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-72113.

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The subject of this project is to develop an information system for recording study achievements of primary and secondary school students with an online access for their parents. In the first part, the author focuses on a survey of current supply of similar applications already on the market and their properties, with a priority look at the way how they are provided. In the second part the author drafts and develops a new and simple information system, which can compete with other rough applications. Emphasis is given to the simplicity of the application as well as its usage. This application is designed to be provided as 'Software as a service' and therefore is easy to employ.

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Wepiwé, Giscard. "HiPeer: an evolutionary approach to P2P systems." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980482771.

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Cavalcanti, de Castro Marcel. "Enhancing P2P Systems over Wireless Mesh Networks." Doctoral thesis, Karlstads universitet, Avdelningen för datavetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-8691.

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Due to its ability to deliver scalable and fault-tolerant solutions, applications based on the peer-to-peer (P2P) paradigm are used by millions of users on the internet. Recently, wireless mesh networks (WMNs) have attracted a lot of interest from both academia and industry, because of their potential to provide flexible and alternative broadband wireless internet connectivity. However, due to various reasons such as unstable wireless link characteristics and multi-hop forwarding operation, the performance of current P2P systems is rather low in WMNs. This dissertation studies the technological challenges involved while deploying P2P systems over WMNs. We study the benefits of location-awareness and resource replication to the P2P overlay while targeting efficient resource lookup in WMNs. We further propose a cross-layer information exchange between the P2P overlay and the WMN in order to reduce resource lookup delay by augmenting the overlay routing table with physical neighborhood and resource lookup history information. Aiming to achieve throughput maximization and fairness in P2P systems, we model the peer selection problem as a mathematical optimization problem by using a set of mixed integer linear equations. A study of the model reveals the relationship between peer selection, resource replication and channel assignment on the performance of P2P systems over WMNs. We extend the model by formulating the P2P download problem as chunk scheduling problem. As a novelty, we introduce constraints to model the capacity limitations of the network due to the given routing and channel assignment strategy. Based on the analysis of the model, we propose a new peer selection algorithm which incorporates network load information and multi-path routing capability. By conducting testbed experiments, we evaluate the achievable throughput in multi-channel multi-radio WMNs. We show that the adjacent channel interference (ACI) problem in multi-radio systems can be mitigated, making better use of the available spectrum. Important lessons learned are also outlined in order to design practical channel and channel bandwidth assignment algorithms in multi-channel multi-radio WMNs.

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Kašparec, Michal. "Víceúčelový informační systém založený na PHP frameworku." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220297.

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This project compare several well-known PHP frameworks and their main characteristics. Creating the content management system with using sophisticated administration interface and access rights. Realization module for ordering and managing smart card for public transport company. Using modern payment methods using 3D secure. Dynamically change the price lists, zones and types of cards. It is created checking neighbor zones that can not be chosen meaningless combinations zones.

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Koláček, Vojtěch. "Komplexní webový herní systém." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2011. http://www.nusl.cz/ntk/nusl-237059.

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This Master's Thesis deals with the analysis of technologies for modern web-based user interfaces, and with the design and implementation of a complex web system with focus on an ergonomic and robust graphical user interface. A set of comparison tests is performed on technologies for web-based user interfaces (Ajax, Adobe Flex, and Microsoft Silverlight); throughput, response time, processing and rendering time of each technology is tested. The web system is designed and implemented as an Ajax strategy game which utilizes the YUI JavaScript library on the client side. The server side comprises of a web server implemented in PHP which offers services to the client, and a message server implemented in C++ that facilitates communication with the client in real-time using HTTP long polling. Tests measuring throughput and response time of the user interface analyze the performance and quality of the implemented system. In the end the tests are analyzed, and the advantages, disadvantages, and flaws of the implementation are evaluated.

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Klimeš, Petr. "Rezervační systém využívající grafické možnosti HTML5." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229438.

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The purpose of the thesis is to design and implement on-line reservation system, which will graphically display an interactive map of the reservation place and will enable to create and redesign these places. The system is going to serve as reservation and sale tool for tickets on cultural, social and other events.

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Šmigura, Jiří. "Návrh a realizace informačního systému společnosti SnugDesign s.r.o." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2016. http://www.nusl.cz/ntk/nusl-241131.

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The subject of this Master’s thesis is focused on an analysis of promotional agency’s requirements concerned with producing a bespoke Information System. The subsequent evaluation of the current situation becomes together with a result of the analysis of requirements a relevant foundation in formulating a scheme for the solution and for the realization of the Information System.

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Ben, Hafaiedh Khaled. "A Scalable P2P RIA Crawling System with Fault Tolerance." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34646.

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Rich Internet Applications (RIAs) have been widely used in the web over the last decade as they were found to be responsive and user-friendly compared to traditional web applications. RIAs use client-side scripting such as JavaScript which allows for asynchronous updates on the server-side using AJAX (Asynchronous JavaScript and XML). Due to the large size of RIAs and therefore the long time required for crawling, distributed RIA crawling has been introduced with the aim to decrease the crawling time. However, the current RIA crawling systems are not scalable, i.e. they are limited to a relatively low number of crawlers. Furthermore, they do not allow for fault tolerance in case that a failure occurs in one of their components. In this research, we address the scalability and resilience problems when crawling RIAs in a distributed environment and we explore the possibilities of designing an efficient RIA crawling system that is scalable and fault-tolerant. Our approach is to partition the search space among several storage devices (distributed databases) over a peer-to-peer (P2P) network where each database is responsible for storing only a portion of the RIA graph. This makes the distributed data structure invulnerable to a single point of failure. However, accessing the distributed data required by crawlers makes the crawling task challenging when the number of crawlers becomes high. We show by simulation results and analytical reasoning that our system is scalable and fault-tolerant. Furthermore, simulation results show that the crawling time using the P2P crawling system is significantly faster than the crawling time using both the non-distributed crawling system and the distributed crawling system using a single database.

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Thomas, Tony. "Location-based Search Service for a P2P OpenStack System." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240416.

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The thesis work designs and develops a mechanism that enables tosearch for nodes in a Peer-to-Peer (P2P) system based on their geographiclocation. For a P2P node, the mechanism builds and maintainsa distributed search index. We introduce a bootstrapping (or startup)protocol, NSBootstrap, which builds this search index for a P2P node.We also introduce a lookup protocol that utilizes this index, NSSearch.The mechanism has been tested on an emulated P2P environmentwith up to 3000 nodes. The evaluation suggests that the state maintainedon a node grows logarithmically with N, the total number ofP2P nodes in the system. Moreover, a new node joining the P2P systemrequires log(N) steps to converge through our mechanism. Additionally,a valid search query within the scope of the search index iscompleted with log(N) steps. I det här examensarbetet designas och utvecklas en mekanism som möjligör sökning efter Peer-to-peer noder baserat på deras geografiska position. I en peer-to-peer node skapar och underhåller mekanismen ett distribuerat sökindex. I arbetet introduceras ett bootstrapping (eller uppstarts-) protokoll, som vi kallar NS-Bootstrap, som är ansvarigt för att bygga sökindexet för en peer-to-peer-nod. Vi inför också ett sökpro- tokoll som använder detta index, NSSearch. Mekanismen har testats i en emulerad peer-to-peer-miljö med upp till 3000 noder. Den utvär- deringen tyder på att tillståndsdata som upprätthålls i en nod växer logaritmiskt med N, där N är det totala antalet peer-to-peer noder i systemet. Dessutom visar experimenten att en ny node som går med i peer- to-peer systemet kräver log(N ) steg för att konvergera via vår meka- nism. Dessutom, en giltig sökförfrågan inom sökindexets omfattning genomförs med i log(N ) .

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Ribeiro, Ricardo Luiz Mendes. "PFL: do PDS ao PSD." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/8/8131/tde-09092016-130237/.

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Este trabalho aborda a trajetória do PFL (Partido da Frente Liberal), desde a sua fundação em 1985 até 2010, quando já sob nova denominação DEM deixou de contar com seus três principais líderes: Jorge Bornhausen, Marco Maciel e Antônio Carlos Magalhães. A tese busca explicar as razões do sucesso do partido, até 2002, e de sua decadência a partir de então. Como principal hipótese, argumenta-se que a conexão com o governo federal foi a causa principal tanto do sucesso quanto da decadência da legenda, desencadeada pela passagem do PFL para a oposição após a vitória do Partido dos Trabalhadores na eleição presidencial de 2002. A análise da inserção do PFL no presidencialismo de coalizão e a narrativa da atuação dos três principais líderes do partido junto às altas esferas do governo federal foram os principais subsídios para a construção indutiva da comprovação da hipótese acima formulada. This work addresses the path of the PFL (Partido da Frente Liberal), since its foundation in 1985 until 2010, when already under the new name - DEM - no longer count on its three main leaders: Jorge Bornhausen, Marco Maciel and Antonio Carlos Magalhães. The thesis seeks to explain the reasons for the party\'s success, until 2002, and its decline from then on. As the main hypothesis it is claimed that the connection to the federal government was the main cause of both, the success and the decline, triggered by the passage of the PFL to the opposition after the Workers Party (PT) victory in the presidential election of 2002. The analysis of PFL in the Brazilian coalitional presidentialism and the narrative of the three main important party leaders connections with high ranks of federal government provide the inductive proof of the above hypothesis.

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Zhang, Kan. "A cluster based incentive mechanism for P2P systems." Thesis, University of Derby, 2011. http://hdl.handle.net/10545/231451.

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Peer-to-Peer (P2P) networking is distributed computing paradigm, in which the nodes are self-organized and can directly exploit resources from each other without dedicated servers. Free riders in. the Peer-to-Peer systems are the nodes that only consume services but provide little or nothing in return. They seriously degrade the fault-tolerance, scalability and content availability of the Peer-to-Peer systems. The solution to this problem in Peer-to-Peer systems is to have incentive mechanisms that aim to improve the network utility by influencing the nodes to become more cooperative. This thesisp roposess evend esignr equirementsf or an incentivem echanisma ccording to the characteristics of Peer-to-Peer systems, latest distributed computing development trends and the related implementation techniques. This thesis also provides a classification of the existing incentive mechanisms for Peer-to-Peer systems. For each category, the thesis, outlines their principle, provides typical examples, applications and discusses their limitations. Bartering exchange ring based incentive mechanism was found to have the potential of fulfilling all the proposed design requirements. It organizes the nodes with asymmetric interests in the bartering exchange rings, enforcing the nodes to contribute while consuming. However the existing bartering exchanger ing formation approacheso nly rely on historical search records which may lead to a risk of using out of date information. Moreover, these incentive mechanismsla ck of accountability so that the self-interestedr ational nodes can still obtain complete resources and only contribute before finishing the consumption. A novel cluster based incentive mechanism (CBIM) is proposed in this thesis which enables dynamic ring formation by modifying the Query Protocol of the underlyingP2P systems. The query messages become the media that the nodes can use to publish supply and demand information on. The nodes can then cooperate to form a cluster through the query messages while searching. A cluster can be formed when every node publishes same number of requests and provisions in a query message and all the requests can be satisfied. Graph theoretically, a cluster consists of one or more bartering exchange rings. The CBIM also uses a reputation system to alleviate the effect of malicious behaviours. The nodes try to identify free riders by fully utilizing their local transaction information. The identified free riding nodes are blacklisted and thus isolated. The simulation results indicate that by applying the CBIM, the overall request success rate of the network can be considerably improved since the rational nodes are forced to become more cooperative and the free riding behaviours can be identified to a certain extent

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Huang, Fei. "On Reducing Delays in P2P Live Streaming Systems." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29006.

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Анотація:

In the recent decade, peer-to-peer (P2P) technology has greatly enhanced the scalability of multimedia streaming on the Internet by enabling efficient cooperation among end-users. However, existing streaming applications are plagued by the problems of long playback latency and long churn-induced delays. First of all, many streaming applications, such as IPTV and video conferencing, have rigorous constraints on end-to-end delays. Moreover, churn-induced delays, including delays from channel switching and streaming recovery, in current P2P streaming applications are typically in the scale of 10-60 seconds, which is far below the favorable user experience as in cable TV systems. These two issues in terms of playback latency and churn-induced delays have hindered the extensive commercial deployment of P2P systems. Motivated by this, in this dissertation, we focus on reducing delays in P2P live streaming systems. Specifically, we propose solutions for reducing delays in P2P live streaming systems in four problem spaces: (1) minimizing the maximum end-to-end delay in P2P streaming; (2) minimizing the average end-to-end delay in P2P streaming; (3) minimizing the average delay in multi-channel P2P streaming; and (4) reducing churn-induced delays. We devise a streaming scheme to minimize the maximum end-to-end streaming delay under a mesh-based overlay network paradigm. We call this problem, the MDPS problem. We formulate the MDPS problem and prove its NP-completeness. We then present a polynomial-time approximation algorithm, called Fastream-I, for this problem, and show that the performance of Fastream-I is bounded by a ratio of O(SQRT(log n)), where n is the number of peers in the system. We also develop a distributed version of Fastream-I that can adapt to network dynamics. Our simulation study reveals the effectiveness of Fastream-I, and shows a reasonable message overhead. While Fastream-I yields the minimum maximum end-to-end streaming delay (within a factor of O(SQRT(log n)), in many P2P settings, users may desire the minimum average end-to-end P2P streaming delay. Towards this, we devise a streaming scheme which optimizes the bandwidth allocation to achieve the minimum average end-to-end P2P streaming delay. We call this problem, the MADPS problem. We first develop a generic analytical framework for the MADPS problem. We then present Fastream-II as a solution to the MADPS problem. The core part of Fastream-II is a fast approximation algorithm, called APX-Fastream-II, based on primal-dual schema. We prove that the performance of APX-Fastream-II is bounded by a ratio of 1+w, where w is an adjustable input parameter. Furthermore, we show that the flexibility of w provides a trade-off between the approximation factor and the running time of Fastream-II. The third problem space of the dissertation is minimizing the average delay in multi-channel P2P streaming systems. Toward this, we present an algorithm, called Fastream-III. To reduce the influence from frequent channel-switching behavior, we build Fastream-III for the view-upload decoupling (VUD) model, where the uploaded content from a serving node is independent of the channel it views. We devise an approximation algorithm based on primal-dual schema for the critical component of Fastream-III, called APX-Fastream-III. In contrast to APX-Fastream-II, APX-Fastream-III addresses the extra complexity in the multichannel scenario and maintains the approximation bound by a ratio of 1+w. Besides playback lag, delays occurring in P2P streaming may arise from two other factors: node churn and channel switching. Since both stem from the re-connecting request in churn, we call them churn-induced delays. Optimizing churn-induced delays is the dissertation's fourth problem space. Toward this, we propose NAP, a novel agent-based P2P scheme, that provides preventive connections to all channels. Each channel in NAP selects powerful peers as agents to represent the peers in the channel to minimize control and message overheads. Agents distill the bootstrapping peers with superior bandwidth and lifetime expectation to quickly serve the viewer in the initial period of streaming. We build a queueing theory model to analyze NAP. Based on this model, we numerically compare NAP's performance with past efforts. The results of the numerical analysis reveal the effectiveness of NAP. Ph. D.

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36

Ullah, Ihsan. "Towards user-aware P2P live video streaming systems." Troyes, 2011. http://www.theses.fr/2011TROY0012.

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De part son support du facteur d’échelle et son faible coût de déploiement, le modèle Pair-à-Pair (P2P) est un excellent support pour les applications de diffusion vidéo sur Internet. Toutefois, étant donné que ce modèle inclue dans la diffusion de contenu les hôtes finaux contrôlés par les utilisateurs, le comportement de ces derniers impacte directement la performance de ces applications induisant des problématiques de qualité de service. Dans cette thèse, nous intégrons le comportement de l’utilisateur pour l’amélioration de performance des systèmes pair-à-pair de diffusion de contenu vidéo en direct. Tout d’abord, nous présentons une synthèse des mesures à grande échelle qui nous permet de comprendre le comportement d’un utilisateur dans sa globalité. Nous présentons ensuite deux modèles. Le premier modèle, non-contextuel, s’appuie uniquement sur l’historique des sessions passées. Il est basé sur deux méthodes statistiques, l’une basée sur la moyenne mobile et l’autre sur l’inférence Bayésienne. Le second modèle est un réseau Bayésien qui considère toutes les variables identifiées dans la synthèse des mesures. Nous validons ce modèle par simulation sur des traces de comportements réalistes générés synthétiquement à partir d’un modèle semi-Markovien. Nous proposons enfin deux stratégies pour stabiliser la topologie d’un réseau P2P et analysons l’amélioration de la performance par expérimentations dans un réseau local et sur PlanetLab et montrons le gain apporté par nos travaux Potential scalability and low deployment cost of the Peer-to-Peer (P2P) architecture makes it a favorable choice for video streaming services. P2P systems involve end-hosts, called peers, in the stream delivery task by turning them into relays. Since peers are controlled by users, their behavior directly impacts the performance of these systems. Current approaches lack a comprehensive consideration of user behavior, hence suffering from Quality-of-Service issues. In this thesis, we focus on user behavior for performance improvement of P2P live streaming systems. To precisely understand the user behavior, we perform a synthesis of its measurements and based on it, we propose both a non-contextual and a contextual model. The former model includes two statistical methods, one based on exponential moving average and the other on Bayesian inference. Both of them only rely on the history of past sessions. The later model consists in a Bayesian network model that takes into account all variables identified in user behavior measurements. We validate our model through simulations over synthetic traces of realistic user behaviors generated through a semi-Markovian model. Finally, we propose two strategies that make use of our models to make P2P live streaming systems user-aware. These mechanisms are aimed at the stabilization of the overlay. Experiments in a LAN environment and over PlanetLab show that our approaches significantly improve the performance of an existing system

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37

Huang, Zhe. "Design of heterogeneous P2P video-on-demand systems /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?ECED%202008%20HUANG.

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Jínek, Tomáš. "Návrh, tvorba a implementace softwarové aplikace ve firemním prostředí." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2020. http://www.nusl.cz/ntk/nusl-417686.

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The main goal of this thesis is design and implement information system Dropohs into business environment, that will create and manage eshops, which will automatically communicate with online service Dropshipping for autonomous solution of orders and their distribution. Next goal will be to analyze this system after running it in real environment. This system was made with MVC based PHP framework.

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Kumar, Rakesh. "PeerSelector: A framework for grouping peers in a P2P system." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99561.

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This master thesis presents a framework called PeerSelector that has been designed and implemented to group peers in a Peer-to-Peer (P2P) system according to certain criteria. The framework is portable and can be deployed with any distributed P2P system. We devised the framework with such functionality in mind because we consider that grouping peers according to certain criteria can benefit the users of the system by providing them with more flexibility to group peers according to their own interests, without depending on entities such as ISPs for peer clustering. We designed and implemented a modular architecture for the framework. More specifically, PeerSelector consists of modules that implement basic functionalities such as grouping peers according to geo-location, RTT-based latency, and the number of AS (Autonomous System) hops. When peers are grouped according to the respective metrics, they are stored in queues, namely the distance, latency, and hop-count queues. Any P2P system that is integrated with our framework fetches peers from such queues, on demand. The results from the framework functionality testing show that the framework is successfully able to cluster peers according to the user's indicated interest. In addition, the framework has been integrated with two existing P2P protocols with minor adjustments, confirming the flexibility and portability of the framework across applications. We have carried out experiments to investigate if using our peer clustering techniques helps a P2P client increase its download performance. In our experiments with a live swarm, we learned that grouping peers according to geo-location does not influence the download performance drastically: download performance increases slightly or remains the same for almost 75 percent of the cases. For the two other clustering metrics, latency and AS hops, our preliminary experimental results don't always show an improvement of the client's download performance. Denna examensarbete presenterar en konstruktion kallad PeerSelector som har blivit designat och implementerat för att gruppera klienter i ett P2P-system efter vissa kriterier. Konstruktionen är portabel och kan användas med alla distribuerade P2P-system. PeerSelector är utformat så att användarna kan gruppera klienterna efter deras egna intressen, vilket ger ökad flexibilitet, utan att vara beroende av enheter så som ISP. Vi har designat och använt en modulär arkitektur för konstruktionen av PeerSelector. Detta betyder att den består av moduler som utför basfunktioner så som att gruppera klienterna efter geografiskt läge, RTT-baserad fördröjning, och antal AS-stopp. När klienterna är grupperade efter respektive ämnesdomän, är de förpassade in i olika kösystem, i synnerhet efter sträcka, fördröjning och stopp-räkning. Alla P2P-system som är integrerade med vår konstruktion hämtar på begäran klienter från dessa kösystem. Resultaten från funktionalitetstester visar att PeerSelector kan gruppera klienter efter användarens intressen. Vidare har denna konstruktion inkorporerats med två existerande P2Pprotokoll genom mindre justeringar, vilket bekräftar såväl flexibiliteten och portabiliteten av konstruktionen. Vi har genomfört experiment för att undersöka om användandet av våra klientgrupperande tekniker hjälper P2P klienter att öka deras nedladdningshastighet. Genom våra experiment lärde vi oss att grupperandet av klienter efter geografisk position inte nämnvärt påverkar nedladdningshastigheten, den ökar något eller förblir det samma i ca 75 % av fallen. I två andra mätningar, fördröjning och AS stopp, visade vårt första experimentella resultat inte alltid en förbättring av klientens nedladdningshastighet.

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Passos, Miguel Ângelo Valente de. "A geolocalização na PSP: a atualidade e potencialidades futuras." Master's thesis, 2020. http://hdl.handle.net/10400.26/32961.

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As tecnologias têm, desde a década de 50 do século passado, tomado um papel cada vez mais preponderante no suporte a toda a atividade desenvolvida pelo Ser Humano. Veja-se o exemplo da pandemia COVID-19 (decretada em 20 de março de 2020 através do Decreto n.º 2-A/2020) que obrigou ao encerramento de diversas instituições e empresas, nomeadamente escolas e grandes superfícies comerciais. Só graças à exploração das tecnologias disponíveis é que os alunos têm acesso aos conteúdos escolares e as empresas têm a possibilidade de laborar em regime de teletrabalho. As Polícias enquanto instituições fundamentais para a manutenção do Estado de Direito Democrático encontram-se em constante atualização tecnológica, por forma a procurarem desenvolver métodos de potenciar a sua atividade através dessas mesmas tecnologias atualmente disponíveis. Uma dessas ferramentas é a georreferenciação dos recursos policiais, mas também das mais diversas ocorrências. Verificámos que são escassos os estudos que analisam a aplicação da ferramenta da geolocalização por Polícias. Por haver uma lacuna de estudos nesta área, optámos por fazer uma análise sobre a utilização da georreferenciação pela PSP em 2020. Inicialmente fizemos uma súmula teórica referente ao funcionamento desta tecnologia e posteriormente apresentamos as conclusões de alguns estudos alusivos à utilização da georreferenciação pelas Polícias. Em termos metodológicos, as técnicas utilizadas foram as entrevistas a polícias que devido à sua função atual têm conhecimento empírico da utilização desta ferramenta na PSP. Consideramos também serem as pessoas indicadas para nos assinalarem as vantagens, mas também possíveis desvantagens e/ou sugestões de melhorias da exploração desta ferramenta. Como forma de sistematizar e comparar a informação mais pertinente dessas entrevistas utilizamos, por fim, a técnica de análise de conteúdo que nos permitiu inferir e contribuir para a resposta aos objetivos de investigação. Do presente estudo pudemos concluir que atualmente se verifica uma falta de investimento económico e académico nesta área, mas também a necessidade de interligação entre a ferramenta de georreferenciação e o SEI. Technologies have, since the '50s of the last century, taken an increasingly preponderant role in supporting all the activity developed by the Human Being. See the example of the pandemic COVID-19 (enacted on March 20, 2020, through Decree No. 2-A / 2020) that forced the closure of several institutions and companies, namely schools and large commercial areas. Only thanks to the exploitation of available technologies do students have access to school content and companies can work in teleworking. The Police as fundamental institutions for the maintenance of the State of Democratic Law are in constant technological update, to seek to develop methods to enhance their activity through these same technologies currently available. One of these tools is the georeferencing of police resources, but also the most diverse occurrences. We found that few studies analyze the application of the geolocation tool by police officers. As there is a lack of studies in this area, we opted to carry out an analysis of the use of georeferencing by PSP in 2020. Initially we made a theoretical summary regarding the operation of this technology and later we present the conclusions of some studies referring to the use of georeferencing by the Police. In methodological terms, the techniques used were interviews with police officers who, due to their current role, have empirical knowledge of the use of this tool in PSP. We also consider that people are indicated to point out the advantages, but also possible disadvantages and / or suggestions for improvements in the exploitation of this tool. Finally, as a way of systematizing and comparing the most relevant information from these interviews, we used the content analysis technique that allowed us to infer and contribute to the response to the research objectives. From the present study we can conclude that there is currently a lack of economic and academic investment in this area, but also the need for interconnection between the georeferencing tool and the SEI.

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Dhadphale, Apurv Ashok. "The reputation system for robust, structured p2p systems /." 2009. http://hdl.handle.net/10106/2051.

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Teo, Chung Piaw, Jim Dai, and Rajeeva Lochana Moorthy. "On Optimizing PSA Berth Planning System." 2003. http://hdl.handle.net/1721.1/3720.

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Competition among container ports continues to increase as the differentiation of hub ports and feeder ports progresses. Managers in many container terminals are trying to attract carriers by automating handling equipment, providing and speeding up various services, and furnishing the most current information on the flow of containers. At the same time, however, they are trying to reduce costs by utilizing resources efficiently, including human resources, berths, container yards, quay cranes, and various yard equipment. When planning berth usage, the berthing time and the exact position of each vessel at the wharf, as well as various quay side resources are usually determined in the process. Several variables must be considered, including the length overall (LOA) and arrival time of each vessel, the number of containers for discharging and loading, and the storage location of outbound/inbound containers to be loaded onto/discharged from the corresponding vessel. Furthermore, we aim to propose berthing plan that will be "robust", since the actual arrival time of each vessel can vary substantially from forecast. This is particular important for vessels from priority customers (called priority vessels hereon), who have been promised berth-on-arrival (i.e. within two hours of arriving) service guarantee in their contract with PSA. A robust plan will also helps to minimize the frequent updates (changes) to berthing plan that have repercussion in resource and sta deployment within the terminal. Thus, the problem reduces to one of finding a berthing plan, so that priority vessels can be berthed-on-arrival with high probability, and the vessels can be berthed as close to their preferred locations as possible, to reduce the cost of transporting the containers within the terminal. In this paper, we described an approach to address this problem. Singapore-MIT Alliance (SMA)

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Sidhom, Iyadh. "A Distributed SIP P2P telephony system." Thesis, 2008. http://spectrum.library.concordia.ca/976087/1/MR42342.pdf.

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Since the telephone was invented, it has revolutionalized the telecommunications and enabled people to talk to each other over long distances. Through the years, the telephone has been greatly improved and many new models have been developed to serve the different needs of the diversified set of users. Peer-to-peer systems inherently have high scalability, robustness and fault tolerance because there is no centralized server and the network self-organizes itself. These features can be used in order to construct peer-to-peer internet telephony systems where there is no central server and with a lower cost than the current internet telephony systems. In this thesis, we propose a fully distributed peer-to-peer architecture, called SIP2P, for the Session Initiation Protocol (SIP). Peers connect directly to other peers, constructing an overlay network of peers which communicate to each other in order to provide the same services as the central server in the conventional SIP. The nodes that define the overlay not only act as an ordinary SIP user agent but they can also perform all together the role of the SIP proxy, SIP register and the SIP location service. The behavior of the conventional SIP servers is distributed over all the nodes participating in the overlay. An implementation of the SIP2P system concludes the thesis in order to validate and evaluate its distributed design

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Liu, Shin-Ho, and 劉欣和. "Implementation of the P2P-IPTV System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/76061613682521397129.

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碩士 國立臺灣科技大學 電機工程系 97 A real-time application layer multicast system has been developed in this thesis. The system comprises: one tracker server, one live media streaming server and many user terminal peers. When one new peer requests the media server to join the IPTV system, the tracker server determine to accept or not by recognizing its ID. To improve the IPTV service efficiency, the system would select a parent peer with low-delay and uplink capability better than the incoming peer. It would maintain the basic stable transmission framework. When one peer determined to leave the multicast tree, it has to find for each children peer a new parent peer according to above rules before updating the parent peer parameter of current one. In addition, the system can adjust the streaming bandwidth of media server in accordance with current network condition. When one peer received the import streaming, it would also out-port the streaming to other online peers, which would help to evenly distribute the transmission loading for the whole IPTV system. The key of user profile is encrypted with AES. We have implemented one a multicast system that integrates tracker server, live media streaming server and user terminal. Experiments show that the average frame rate and the transmission delay of all peers can be maintained at acceptable performances even when most peers are with low uplink capability.

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Liang, Hong-Han, and 梁宏漢. "A P2P-based QoS Monitor System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/57112690430380555851.

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碩士 國立中央大學 資訊工程研究所 95 Network services are more and more popular, and every Internet Service Provider (ISP) begins to offer all kinds of network services, including Voice over IP (VoIP), video conference and so on. In order to receive the normal service, these services must meet Quality of Service (QoS) requirements demanded by customers. To define normal services, the customers will sign Service Level Agreements (SLA) with ISPs to ensure ISP can reach QoS, which customers demand. Because the customers may use the network services in different ISPs, network managers are not able to know network service status across network domains, and the right of the customers is ignored. This thesis proposes a P2P-based QoS Monitoring System (QMS). It considers the customers view, gathers a large number of users that distributed in the network, and makes comprehensive network connection service monitoring, so that common customers can use this system to determine whether its network meets SLA signed with the ISP, and guarantees customers'' right. The proposed system uses P2P architecture to improve flexibility and robustness. Even if a user leaves this system, another user at the same network domain can replace to maintain QoS information of monitoring continuously. In addition, the feature of the P2P architecture that users are distributed everywhere is used to increase the range of QoS monitoring and ISPs need not to change configurations of network devices. Every monitored destination uses 2696.536 bps, it is enough for ADSL. The proposed system can avoid problem that user cannot get QoS information because ISPs block packets from some domains in using firewall or network device configuration. The proposed system can get QoS information from other nodes. This system is divided into the two kinds of roles, One is the Monitor Agent, which is installed in customers’ computers, and monitors each other to get network connection information between two Monitor Agents; Another is the Monitor Information Collector, which collects network connection information form the Monitor Agent and provides information to all customers who install this system.

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Chen, Wei-Dun, and 陳煒惇. "Location-based P2P Mobile Guide System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/49712618091605050718.

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碩士 真理大學 資訊工程學系碩士班 100 In recent years, location-based services have received increased attention, with many developed practical applications for GPS, such as traffic navigation, travel guides, album maps, etc. This study developed a P2P mobile guide system that supports both indoor and outdoor locations. When a user walks indoor or outdoor exhibition areas with mobile guide equipment, this system can indicate the position of the user, and the location-based P2P clustering mechanism enables the user to download relevant 3D scenes and multimedia information in P2P mode from nearby peers with the same guide interest, thus, guide data transmission efficiency is effectively increased.

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Ho, Fang. "OBN: An on-demand P2P streaming system." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-1303200709323605.

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"Modeling and analysis of P2P VoD system." 2012. http://library.cuhk.edu.hk/record=b5549552.

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点对点网络是今年兴起的一个热门研究课题。点对点网络有非常好的文件分发能力，在传统的服务器客模式下，服务器需要为每位客建立独立的链接。随着用的增加服务器的能力很快会变成瓶颈。点对点网络的优势在于能够通过下载相同内容的客共享交换内容，从而利用每位客的上传带宽.基于这个特点,即使没有服务器的帮助，只要客都无私的共享自己的内容，点对点网络可以以非常高的效率分发大文件。目前已经有很对研究成果是关于点对点网络的体系结构设计和网络协议设计。但随着文件大小和数量的快速增长，客除了贡献带宽还会贡献一块硬盘来缓存一些自己并不感兴趣的内容来增加客间互相帮助的概率。尤其是视频点播应用的兴起给点对点网络的内容传输带来了新的挑战。例如如何能保证所有客流畅的点播视频，以及如何优化每个客缓存的内容来最小化服务器带宽需求。在本篇论文中，我们将集中讨论点对点视频点播系统并解决以下问题： 我们的目的是节省服务器带宽。一个最基本的问题是客节点的最优缓存替换策略问题。首先我们定义了完美请求调度策略，在这个调度策略的基础上提出RLB 缓存替换策略从而得到最小化服务器带宽。 第二个问题是不同的请求调度策略和最优的缓存替换策略之间是如何相互影响的。我们提出了FSBD 模型。通过研究每个客能发出的请求数目，我们恩能够比较不同的缓存替换策略和不同的调度策略之间的关系。 最后一个问题，我们研究了点对点视频点播系统在电影数量远远多于客数量的极端情况。在这种情况下，由于客只能贡献非常少量的硬盘来缓存电影，提供电影的覆盖和提高视频点播系统的吞吐量是一个互相矛盾的问题。两者不能同时达到最优。 除了以上的理论分析，我们通过模拟试验来验证理论模型的正确性。此外我们还提出了非常简单有效的分布式缓存替换策略用于实际系统的实现。相信以上的研究工作对于点对点视频系统的设计和实现有重要的帮助。 Peer-to-Peer (P2P) systems become a hot research topic in recent years because of their excellent ability for content distribution. In traditional Client/Server(C/S) mode, the server must serve each user directly. The server capacity is the bottleneck when user population becomes large. The power of P2P network is to encourage peers to share common content with each other to offload server. The P2P systems distribute content very efficiently if all peers help others selflessly with minimal support from the server. There are many works dedicated to the architecture and protocol design for P2P systems. These works study how to organize peers to exchange content efficiently. As content size and content population are growing very fast today, P2P networks are used to support Video on Demand (VoD) streaming service. For VoD streaming, besides bandwidth, the peers are required to contribute storage to cache some content that they may not be interested in. The new challenges include how to guarantee that all peers can play video smoothly and how to cache the content at different peers to minimize server load . In this thesis, we study the following problems in a P2P VoD streaming system: What the optimal movie replication strategy to minimize server load is. To study this problem, we first make an assumption to simplify the P2P service model. We assume that all peers follow a Perfect Fair Sharing (PFS) scheduling strategy. Based on this setup, we proposed Random Load Balance (RLB) algorithm to achieve minimum server load. We derive analytical bounds on the achieved server load. Next, We observe that different P2P scheduling strategies lead to different “optimal replication strategies. Our second setup is to relax the assumption of perfect fair sharing scheduling by proposing a Fair Sharing with Bounded Degree (FSBD) model, parameterized by the maximum number of peers that can be used to serve a single request. PFS is a special case of FSBD. We compare different replication strategies for different in-degree bounds and see how and why different replication strategies are favored depending on the in-degree. For the last problem, we let the movie population become large and assume that there is some skewness in movie popularity. Then peers can’t reduce server load and provide availability of all movies at the same time. In other words, peers must be selective in replicating sufficiently popular movies. It is a tradeoff between coverage of movies and streaming throughput provided by the P2P system. Besides analysis, we also use simulation to validate our models. As a robust solution under different P2P service models, we proposed a simple adaptive movie replication algorithm with computation efficiency. Our study leads to several fundamental insights for the design of P2P VoD systems in practice. Detailed summary in vernacular field only. Detailed summary in vernacular field only. Detailed summary in vernacular field only. Detailed summary in vernacular field only. Detailed summary in vernacular field only. Zhou, Yipeng. Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. Includes bibliographical references (leaves 162-170). Abstract also in Chinese. Abstract --- p.i Acknowledgement --- p.i Chapter 1 --- Introduction --- p.1 Chapter 1.1 --- Background --- p.2 Chapter 1.2 --- P2P VoD Streaming System --- p.6 Chapter 1.3 --- Contribution --- p.11 Chapter 1.4 --- Organization --- p.12 Chapter 2 --- Model --- p.14 Chapter 2.1 --- Assumptions and Notations --- p.15 Chapter 2.2 --- User Behavior Model --- p.19 Chapter 2.3 --- Movie Popularity --- p.22 Chapter 2.4 --- Optimizing Server Load --- p.25 Chapter 3 --- Analysis --- p.30 Chapter 3.1 --- Request Scheduling Strategy --- p.31 Chapter 3.2 --- Fixed Bandwidth Allocation --- p.33 Chapter 3.2.1 --- FBA with Homogeneous Peers --- p.33 Chapter 3.2.2 --- FBA with Heterogeneous Peers --- p.37 Chapter 3.3 --- Perfect Fair Sharing --- p.37 Chapter 3.3.1 --- PFS with Homogeneous Peers --- p.41 Chapter 3.3.2 --- PFS with Heterogeneous Peers --- p.48 Chapter 3.4 --- Fair Sharing with Fixed Degree --- p.50 Chapter 3.5 --- FBA v.s. PFS v.s. FSFD --- p.53 Chapter 3.6 --- Fair Sharing with Bounded Degree --- p.55 Chapter 4 --- Adaptive Movie Replication Algorithms --- p.62 Chapter 4.1 --- Adaptive RLB Algorithm --- p.63 Chapter 4.2 --- Distributed Adaptive Replication Algorithm --- p.66 Chapter 4.2.1 --- Other Algorithms --- p.70 Chapter 5 --- Simulation --- p.73 Chapter 5.1 --- Simulation Setting --- p.74 Chapter 5.2 --- Simulation for PFS --- p.76 Chapter 5.2.1 --- Stationary demand and static replication assignment --- p.77 Chapter 5.2.2 --- Evaluate adaptive replication algorithms --- p.81 Chapter 5.2.3 --- Performance analysis and discussion --- p.85 Chapter 5.2.4 --- Copy Distribution of ARLB --- p.89 Chapter 5.3 --- Simulation for FBA, FSFD and FSBD --- p.91 Chapter 5.3.1 --- Model Validation --- p.91 Chapter 5.3.2 --- Test of DAR Algorithm --- p.93 Chapter 5.3.3 --- Robustness Validation --- p.96 Chapter 6 --- Division of Labor --- p.102 Chapter 6.1 --- Background: models and algorithms --- p.103 Chapter 6.2 --- Availability versus Throughput --- p.106 Chapter 6.2.1 --- ATD and its Drawbacks --- p.107 Chapter 6.2.2 --- Coverage Assured Replication --- p.110 Chapter 6.2.3 --- Automatic Division of Labor --- p.113 Chapter 6.3 --- Optimal Coverage --- p.115 Chapter 6.3.1 --- Save Most Popular Movies for P2P --- p.115 Chapter 6.3.2 --- The Value of Optimal K --- p.118 Chapter 6.3.3 --- Performance with or without CA --- p.121 Chapter 6.4 --- Sensitivity --- p.122 Chapter 6.4.1 --- θ versus K* --- p.122 Chapter 6.4.2 --- The Effect of Popularity Skewness:θ --- p.123 Chapter 6.4.3 --- System Parameters versus K* --- p.124 Chapter 6.4.4 --- The Effect of System Parameters --- p.126 Chapter 7 --- Related Work --- p.131 Chapter 8 --- Conclusion --- p.141 Chapter A --- Equation Derivation --- p.144 Bibliography --- p.162

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Fang, Ho, and 方鶴. "OBN: An on-demand P2P streaming system." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/91898574293956404387.

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碩士 國立清華大學 資訊系統與應用研究所 94 For peer-to-peer (P2P) media streaming systems, one of the critical issues is to discover suitable supplying peers which can provide required media segments to the requesting peer. Through a simulation-based study, OBN [4] is shown to be a promising mechanism for finding streaming suppliers. OBN presents a special peering structure and corresponding routing approach for efficient supplier discovery in an on-demand P2P media streaming system. We examine the feasibility of OBN by realizing it on top of PlanetLab [1]. This thesis contributes on further OBN system design and implementation which take into account the additional requirements imposed by the real network environment.

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Yang, Ya-Chu, and 楊雅筑. "P2P Real-Time Road Traffic Navigation System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/45204203283585692657.

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碩士 國立交通大學 網路工程研究所 96 Existing centralized real-time traffic information systems provide excellent road guidance. However, the cost for constructing and maintaining the traffic center is expensive. Recently, several decentralized ad-hoc based traffic information systems are proposed. Vehicles in this kind of system detect traffic conditions with GPS devices and exchange observed traffic conditions with each other through inter-vehicle communication. However, ad-hoc based traffic information system has problem to efficiently disseminated traffic condition in large scale places when the penetration rate is low. For this reason, we propose a combined IVC and infrastructure-based decentralized P2P real-time road traffic information system. The system aims at providing accurate traffic reports and supporting efficient traffic report lookup. The system is organized as a two-layer hierarchical architecture. All vehicles participate in the ad-hoc network and broadcast observed traffic condition through IVC. Parts of vehicles are elected as super nodes and they form a P2P overlay atop ad-hoc network to support traffic report lookup through infrastructure-based wireless network interfaces. Simulation results demonstrate that the proposed system dose provide efficient traffic report lookup.

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