4,601 research outputs found

    A theoretical and computational basis for CATNETS

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    The main content of this report is the identification and definition of market mechanisms for Application Layer Networks (ALNs). On basis of the structured Market Engineering process, the work comprises the identification of requirements which adequate market mechanisms for ALNs have to fulfill. Subsequently, two mechanisms for each, the centralized and the decentralized case are described in this document. These build the theoretical foundation for the work within the following two years of the CATNETS project. --Grid Computing

    DĂ©couverte et allocation des ressources pour le traitement de requĂȘtes dans les systĂšmes grilles

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    De nos jours, les systĂšmes Grille, grĂące Ă  leur importante capacitĂ© de calcul et de stockage ainsi que leur disponibilitĂ©, constituent l'un des plus intĂ©ressants environnements informatiques. Dans beaucoup de diffĂ©rents domaines, on constate l'utilisation frĂ©quente des facilitĂ©s que les environnements Grille procurent. Le traitement des requĂȘtes distribuĂ©es est l'un de ces domaines oĂč il existe de grandes activitĂ©s de recherche en cours, pour transfĂ©rer l'environnement sous-jacent des systĂšmes distribuĂ©s et parallĂšles Ă  l'environnement Grille. Dans le cadre de cette thĂšse, nous nous concentrons sur la dĂ©couverte des ressources et des algorithmes d'allocation de ressources pour le traitement des requĂȘtes dans les environnements Grille. Pour ce faire, nous proposons un algorithme de dĂ©couverte des ressources pour le traitement des requĂȘtes dans les systĂšmes Grille en introduisant le contrĂŽle de topologie auto-stabilisant et l'algorithme de dĂ©couverte des ressources dirigĂ© par l'Ă©lection convergente. Ensuite, nous prĂ©sentons un algorithme d'allocation des ressources, qui rĂ©alise l'allocation des ressources pour les requĂȘtes d'opĂ©rateur de jointure simple par la gĂ©nĂ©ration d'un espace de recherche rĂ©duit pour les nƓuds candidats et en tenant compte des proximitĂ©s des candidats aux sources de donnĂ©es. Nous prĂ©sentons Ă©galement un autre algorithme d'allocation des ressources pour les requĂȘtes d'opĂ©rateurs de jointure multiple. Enfin, on propose un algorithme d'allocation de ressources, qui apporte une tolĂ©rance aux pannes lors de l'exĂ©cution de la requĂȘte par l'utilisation de la rĂ©plication passive d'opĂ©rateurs Ă  Ă©tat. La contribution gĂ©nĂ©rale de cette thĂšse est double. PremiĂšrement, nous proposons un nouvel algorithme de dĂ©couverte de ressource en tenant compte des caractĂ©ristiques des environnements Grille. Nous nous adressons Ă©galement aux problĂšmes d'extensibilitĂ© et de dynamicitĂ© en construisant une topologie efficace sur l'environnement Grille et en utilisant le concept d'auto-stabilisation, et par la suite nous adressons le problĂšme de l'hĂ©tĂ©rogĂ©nĂ©itĂ© en proposant l'algorithme de dĂ©couverte de ressources dirigĂ© par l'Ă©lection convergente. La deuxiĂšme contribution de cette thĂšse est la proposition d'un nouvel algorithme d'allocation des ressources en tenant compte des caractĂ©ristiques de l'environnement Grille. Nous abordons les problĂšmes causĂ©s par la grande Ă©chelle caractĂ©ristique en rĂ©duisant l'espace de recherche pour les ressources candidats. De ce fait nous rĂ©duisons les coĂ»ts de communication au cours de l'exĂ©cution de la requĂȘte en allouant des nƓuds au plus prĂšs des sources de donnĂ©es. Et enfin nous traitons la dynamicitĂ© des nƓuds, du point de vue de leur existence dans le systĂšme, en proposant un algorithme d'affectation des ressources avec une tolĂ©rance aux pannes.Grid systems are today's one of the most interesting computing environments because of their large computing and storage capabilities and their availability. Many different domains profit the facilities of grid environments. Distributed query processing is one of these domains in which there exists large amounts of ongoing research to port the underlying environment from distributed and parallel systems to the grid environment. In this thesis, we focus on resource discovery and resource allocation algorithms for query processing in grid environments. For this, we propose resource discovery algorithm for query processing in grid systems by introducing self-stabilizing topology control and converge-cast based resource discovery algorithms. Then, we propose a resource allocation algorithm, which realizes allocation of resources for single join operator queries by generating a reduced search space for the candidate nodes and by considering proximities of candidates to the data sources. We also propose another resource allocation algorithm for queries with multiple join operators. Lastly, we propose a fault-tolerant resource allocation algorithm, which provides fault-tolerance during the execution of the query by the use of passive replication of stateful operators. The general contribution of this thesis is twofold. First, we propose a new resource discovery algorithm by considering the characteristics of the grid environments. We address scalability and dynamicity problems by constructing an efficient topology over the grid environment using the self-stabilization concept; and we deal with the heterogeneity problem by proposing the converge-cast based resource discovery algorithm. The second main contribution of this thesis is the proposition of a new resource allocation algorithm considering the characteristics of the grid environment. We tackle the scalability problem by reducing the search space for candidate resources. We decrease the communication costs during the query execution by allocating nodes closer to the data sources. And finally we deal with the dynamicity of nodes, in terms of their existence in the system, by proposing the fault-tolerant resource allocation algorithm

    Theoretical and Computational Basis for Economical Ressource Allocation in Application Layer Networks - Annual Report Year 1

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    This paper identifies and defines suitable market mechanisms for Application Layer Networks (ALNs). On basis of the structured Market Engineering process, the work comprises the identification of requirements which adequate market mechanisms for ALNs have to fulfill. Subsequently, two mechanisms for each, the centralized and the decentralized case are described in this document. --Grid Computing

    Grid resource discovery based on web services

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    The size of grid systems has increased substantially in the last decades. Resource discovery in grid systems is a fundamental task which provides searching and locating necessary resources for a given process. Various different approaches are proposed in literature for this problem. Grid resource discovery using web services is an important approach which has resulted in many tools to become de facto standards of today's grid resource management. In this paper, we propose a survey of recent grid resource discovery studies based on web services. We provide synthesis, analysis and evaluation of these studies by classification. We also give a comparative study of different classes proposed
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