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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Gestion de la qualité de service des systèmes publier/souscrire déployés sur un réseau mobile ad hoc / Gestion de la qualité de service des systèmes publier/souscrire déployés sur un réseau mobile ad hoc

Lahyani abdennadher, Imene 17 December 2015 (has links)
L’objectif de cette thèse est la gestion de la QdS des systèmes publier/souscrire sur MANET. Ceci provoque un maintien permanent de la connectivité entre les parties communicantes du système. Plus précisément, les contributions de cette thèse, sont organisées autour de deux grands axes relatifs aux modules de monitoring et d’analyse de la QdS de ces systèmes dans un contexte ad-hoc. Ceci englobe les etapes de collecte des paramètres de QdS au cours du fonctionnement du système, et de détection des dégradations pouvant l’affecter.Contrairement à ce qui existe dans la littérature, notre module d’analyse, basé sur des méthodes statistiques, se base sur des seuils adaptatifs qui tiennent en comptes de la dynamicité du réseau et des changements affectant le contexte ad-hoc. En outre, le module d’analyse proposé offre à l’utilisateur une variété de choix entre une analyse réactive, proactive et hybride. Notre module permet aussi une localisation des pannes une fois détectées ou prédites. Des expérimentations menées à l’aide du simulateur Jist/Swans ont montré l’efficacité des modules developpés. De plus, une mesure des paramètres de performance du système avant et après introduction des modules développés a montré leur efficacité. Finalement, une étude de la complexité spatiale et temporelle du module analytique proposé a été réalisée. / Mobile ad-hoc networks (MANET) is a set of nodes, communicating meaning wireless channel without any centralized control. The main characteristic of MANET is the frequent mobility of its nodes leading to some dynamic changes of topology. Nodes mobility in such networks introduces possible disconnections between adjacent nodes, and more generally quality of service (QoS) degradation issues that do not fit well with QoS requirements of QoS sensitive applications. Publish/subscribe communicating system has been proposed at the middleware layer in order to communicate mobile entities in MANET. Such system is a decoupled interaction between publishers (or producers) and receivers (or consumers).Our goal in this thesis is to provide a QoS management for publish/subscribe systems when deployed on MANET while assuming a best effort flux at the routing layer. This thesis proposes an analytical model for latency aware publish/subscribe systems on mobile ad-hoc networks. The proposed approach combines both proactive and reactive statistical analysis.On the one hand, the reactive analysis, suitable for multimedia applications, detects failures by approximating latency series with Gumbel distribution. On the other hand, the proactive analysis, suitable for crisis management applications, forecasts failures occurrence relying on Auto Regression or Auto Regressive Integrated Moving Average Formulas. Finally, a hybrid analysis was proposed by dynamically switching from reactive to predictive forms of analysis whenever quality of service violations are noticed. In order to extract failure cause, we refer to the correlation method once failure was detected or predicted. Simulations done, using Jist/Swans simulator, under different scenariosproved the efficiency and accuracy of the proposed scheme.
42

Overlay Neighborhoods for Distributed Publish/Subscribe Systems

Sherafat Kazemzadeh, Reza 07 January 2013 (has links)
The Publish/Subscribe (pub/sub) model has been widely applied in a variety of application scenarios which demand loose-coupling and asynchronous communication between a large number of information sources and sinks. In this model, clients are granted the flexibility to specify their interests at a high level and rely on the pub/sub middleware for delivery of their publications of interest. This increased flexibility and ease of use on the client side results in substantial complexity on part of the pub/sub middleware implementation. Furthermore, for several reasons including improved scalability, availability and avoiding a single point of failure, the pub/sub middleware is commonly composed of a set of collaborating message routers, a.k.a. brokers. The distributed nature of this design further introduces new challenges in ensuring end-to-end reliability as well as efficiency of operation. These challenges are largely unique to the pub/sub model and hence absent in both point-to-point or multicast protocols. This thesis develops solutions that ensure the dependable operation of the pub/sub system by exploiting the notion of overlay neighborhoods in a formal manner. More specifically, brokers maintain information about their neighbors within a configurable distance in the pub/sub overlay and exploit this knowledge to construct alternative forwarding paths or make smart forwarding decisions that improves efficiency, bandwidth utilization and delivery delay, all at the same time. Furthermore, in the face of failures overlay neighborhoods enable fast reconstruction of forwarding paths in the system without compromising its reliability and availability. Finally, as an added benefit of overlay neighborhoods, this thesis develops large-scale algorithms that bring the advantages of the pub/sub model to the domain of file sharing and bulk content dissemination applications. Experimental evaluation results with deployments as large as 1000 nodes illustrate that the pub/sub system scales well and outperforms the traditional BitTorrent protocol in terms of content dissemination delay.
43

應用價值鏈建立台灣暢銷書之成功要素與預測模型 / Applying Vaule Chain to Establish and Predict How to Be the Bestseller in Taiwan

周榆凱, Chou ,Yu-Kai Unknown Date (has links)
圖書出版產業的競爭態勢激烈,是由來已久的問題,就以實際的數據顯示,2004年申請登錄ISBN的新書,種類就高達39713種,可是能在像是金石堂這樣的連鎖書店販售的新書,卻只有23195種;同時,在這二萬多本的新書中,能夠獲得消費者認同與購買的書更是少之又少。就是在這樣的環境中,圖書出版產業該如何生存,成為一個很重要的課題。 圖書出版其實就是藉由文字傳遞作者想要表達的情報,藉以創造利潤的產業。因此,穩定持續比快速週轉重要;要能穩定推出有品質且保障銷售的圖書,例如長銷書以及暢銷書,並建立健全完善的商品規劃與行銷方式,出版社才能有生存的機會與空間。現今出版產業分工清楚,從發行、編輯、業務、行銷、以及印刷管理各功能,都是獨立運作,可是創造出銷售良好的暢銷書,是必須從整體的觀點去審視,透過彼此合作與整合,降低資源浪費或是閒置的問題,產生最大的效益。本研究即以價值鏈各部份做為討論基礎,藉由調查出版從業人員,將市場暢銷書的成功特徵,加以歸納成為成功模式,試圖說明與預測暢銷書所需具備的要件。 圖書產業之價值流程,主要分為「市場資訊蒐集」、「圖書編輯與設計」、「圖書印刷」、「圖書宣傳與發行」、「圖書儲存銷售」、「圖書售後服務」,其各項目都包含了許多項目與因素。藉由因素分析,將價值鏈中『市場資訊收集』歸納出「作者創造需求」與「迎合社會議題」二因素;『文字編輯與設計』則有「內頁呈現與設計」、「書籍內文」、以及「書名與封皮」三因素;『圖書宣傳與設計』是「行銷手法運用」、「市場曝光度」以及「擁有通路力量」。在獲得因素選項後,帶入區別分析與邏輯迴歸模式中,進一步分析何者能成為解釋暢銷書成功之影響因子。 以不分類書種而言,「書名與封皮」、「行銷手法運用」與「市場曝光度」是最後萃取出的重要價值活動,這是導因於目前出版書種過於氾濫,為了讓書籍增加銷售率,出版業者必須讓消費者第一眼就能對書籍有好感,並且配合各樣的行銷方式,利用活動(如:參與書展、研討會等)與廣告,增加書籍在消費者的曝光率,成為市場之暢銷書機會就大增。一般而言,文學類書籍應該是會著重在「書籍內文」,分析結果卻應著重在「行銷手法的運用」,說明消費者對內文接受度已廣泛,如何把書的特性與魅力告訴消費者,才是文學類書籍的銷售的重要條件。受限於財經企管類書籍專業性程度不一,導致進入可能會有障礙。因此,成功之財經企管暢銷書籍,要能在「書名與封皮」給予很親近消費者之名稱,並透過「廣告」與相關議題「活動」之舉辦,向讀者介紹該本書之內容與實用性,增加購買意願。
44

Towards Achieving Highly Parallelized Publish/Subscribe Matching at Line-rates Using Reconfigurable Hardware

Singh, Harshvardhan P. 20 December 2011 (has links)
We present fpga-ToPSS (Toronto Publish/ Subscribe System), an efficient FPGA-based middleware platform geared towards high-frequency and low-latency event processing. fpga-ToPSS is built over reconfigurable hardware---FPGAs---to achieve line-rate processing by exploiting unprecedented degrees of parallelism and potential for pipelining,only available through custom-built, application-specific and low-level logic design. Furthermore, our middleware solution hosts an event processing engine that is built on a hardware-based packet processor and Boolean expression matcher. Our middleware vision extends to a wide range of applications including real-time data analytics, intrusion detection, algorithmic trading, targeted advertisement, and (complex) event processing.
45

Towards Achieving Highly Parallelized Publish/Subscribe Matching at Line-rates Using Reconfigurable Hardware

Singh, Harshvardhan P. 20 December 2011 (has links)
We present fpga-ToPSS (Toronto Publish/ Subscribe System), an efficient FPGA-based middleware platform geared towards high-frequency and low-latency event processing. fpga-ToPSS is built over reconfigurable hardware---FPGAs---to achieve line-rate processing by exploiting unprecedented degrees of parallelism and potential for pipelining,only available through custom-built, application-specific and low-level logic design. Furthermore, our middleware solution hosts an event processing engine that is built on a hardware-based packet processor and Boolean expression matcher. Our middleware vision extends to a wide range of applications including real-time data analytics, intrusion detection, algorithmic trading, targeted advertisement, and (complex) event processing.
46

Information Centric Data Collection and Dissemination Fabric for Smart Infrastructures

Nigam, Aakash 09 December 2013 (has links)
Evolving smart infrastructures requires both content distribution as well as event notification and processing support. Content Centric Networking (CCN), built around named data, is a clean slate network architecture for supporting future applications. Due to its focus on content distribution, CCN does not inherently support Publish-Subscribe event notification, a fundamental building block in computer mediated systems and a critical requirement for smart infrastructure applications. While semantics of content distribution and event notification require different support systems from the underlying network infrastructure, content distribution and event notification can still be united by leveraging similarities in the routing infrastructure. Our Extended-CCN architecture(X-CCN) realizes this to provide lightweight content based pub-sub service at the network layer, which is used to provide advanced publish/subscribe services at higher layers. Light weight content based pub-sub and CCN communication at network layer along with advanced publish/subscribe together are presented as data fabric for the smart infrastructures applications.
47

Information Centric Data Collection and Dissemination Fabric for Smart Infrastructures

Nigam, Aakash 09 December 2013 (has links)
Evolving smart infrastructures requires both content distribution as well as event notification and processing support. Content Centric Networking (CCN), built around named data, is a clean slate network architecture for supporting future applications. Due to its focus on content distribution, CCN does not inherently support Publish-Subscribe event notification, a fundamental building block in computer mediated systems and a critical requirement for smart infrastructure applications. While semantics of content distribution and event notification require different support systems from the underlying network infrastructure, content distribution and event notification can still be united by leveraging similarities in the routing infrastructure. Our Extended-CCN architecture(X-CCN) realizes this to provide lightweight content based pub-sub service at the network layer, which is used to provide advanced publish/subscribe services at higher layers. Light weight content based pub-sub and CCN communication at network layer along with advanced publish/subscribe together are presented as data fabric for the smart infrastructures applications.
48

Optimal and Robust Routing of Subscriptions for Unifying Access to the Past and the Future in Publish/Subscribe

Li, Guoli 18 February 2011 (has links)
A flexible, scalable, and asynchronous middleware abstract is needed for business process management, which involves thousands of tasks and a large number of running instances of large business processes. The content-based publish/subscribe system is an ideal candidate to serve as enterprise service bus for these applications. In the publish/subscribe paradigm, information providers called publishers disseminate publications to all subscribers who have expressed interests by registering subscriptions through a loosely coupled interface. However, the traditional publish/subscribe paradigm only supports stateless subscriptions, that is, event correlation is ignored. Moreover, subscribers can only receive publications issued after their subscriptions. There are many application contexts, however, where access to publications from the past is necessary,such as for replaying a business process execution to debug it. Even more interesting uses arise when data from the past can be correlated with those in the future. Therefore, new languages and new functionalities are needed in the standard publish/subscribe model in order to support business process management. A new subscription language PADRES SQL(PSQL) which can express event patterns and unify both historic and future views for subscribers. PADRES allows a subscriber to access data published both in the past and in the future. Furthermore, complex event detection happens in the broker network. The main difficulties of distributed event detection are routing a composite subscription, including where and how to decompose the composite subscription, and routing the individual parts of the subscription. Our composite subscription routing decisions are based on a cost model which minimizes the routing and detection delay. An adaptive subscription routing protocol is proposed to determine efficient location with dynamic changing workloads. PADRES also provides robust message delivery by exploring alternative paths in a cyclic overlay. Routing optimizations and efficient matching algorithms are studied to improve the performance of the extended publish/subscribe model. With the above features, we propose the Ninos system, the distributed business process execution architecture as a case study,which uses light-weight activity agents to carry out business process execution in a distributed environment. Ninos proves that decentralized business process execution is the trend for next generation products, and the publish/subscribe model is ideal to serve as an enterpriser service bus (ESB) for distributed applications.
49

Overlay Neighborhoods for Distributed Publish/Subscribe Systems

Sherafat Kazemzadeh, Reza 07 January 2013 (has links)
The Publish/Subscribe (pub/sub) model has been widely applied in a variety of application scenarios which demand loose-coupling and asynchronous communication between a large number of information sources and sinks. In this model, clients are granted the flexibility to specify their interests at a high level and rely on the pub/sub middleware for delivery of their publications of interest. This increased flexibility and ease of use on the client side results in substantial complexity on part of the pub/sub middleware implementation. Furthermore, for several reasons including improved scalability, availability and avoiding a single point of failure, the pub/sub middleware is commonly composed of a set of collaborating message routers, a.k.a. brokers. The distributed nature of this design further introduces new challenges in ensuring end-to-end reliability as well as efficiency of operation. These challenges are largely unique to the pub/sub model and hence absent in both point-to-point or multicast protocols. This thesis develops solutions that ensure the dependable operation of the pub/sub system by exploiting the notion of overlay neighborhoods in a formal manner. More specifically, brokers maintain information about their neighbors within a configurable distance in the pub/sub overlay and exploit this knowledge to construct alternative forwarding paths or make smart forwarding decisions that improves efficiency, bandwidth utilization and delivery delay, all at the same time. Furthermore, in the face of failures overlay neighborhoods enable fast reconstruction of forwarding paths in the system without compromising its reliability and availability. Finally, as an added benefit of overlay neighborhoods, this thesis develops large-scale algorithms that bring the advantages of the pub/sub model to the domain of file sharing and bulk content dissemination applications. Experimental evaluation results with deployments as large as 1000 nodes illustrate that the pub/sub system scales well and outperforms the traditional BitTorrent protocol in terms of content dissemination delay.
50

Τεχνολογίες instant messaging σε επίπεδο πελάτη και εξυπηρετητή με την χρήση της υπηρεσίας PubSub

Τόκης, Θεόδωρος 17 February 2015 (has links)
Σκοπός μας είναι να μελετήσουμε, αναπτύξουμε και να υλοποιήσουμε μία υπηρεσία PubSub με την βοήθεια του εργαλείου ανοικτού κώδικα Agsxmpp SDK. Η υπηρεσία αυτή θα είναι διαθέσιμη σε όλους τους χρήστες ενός συστήματος και θα υπάρχει η δυνατότητα στον καθένα να δημιουργεί αναρίθμητα θεματικά «κανάλια» μηνυμάτων κάθε τύπου. Κάθε χρήστης θα έχει δικαίωμα εγγραφής σε ένα τέτοιο «κανάλι» και έτσι θα έχει την δυνατότητα να λαμβάνει τα μηνύματα και τις ανανεώσεις που δημοσιεύονται σε αυτό. Σαν «κανάλια» ορίζουμε τα Nodes, η εγγραφή ορίζεται ως subscribe, η δημοσίευση ως publish και τέλος την ειδοποίηση / παραλαβή ως notification. / Our aim is to study, develop and implement a service with PubSub the help of open source tools Agsxmpp SDK. The service will be available to all users of a system and possible for anyone to create numerous thematic "Channels" each message type. Each user will have the right recording in such a "channel" and thus is able to receive messages and updates posted on this. like "Channels" are defined as Nodes, the record is defined as subscribe, the publication to publish and finally notification / receipt as notification.

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