Encontrados 27 documentos, a visualizar página 1 de 3
Comparing clustering and partitioning strategies
Afonso, Carlos; Ferreira, Fábio; Exposto, José; Pereira, Ana I.In this work we compare balance and edge-cut evaluation metrics to measure the performance of two well-known graph data-grouping algorithms applied to four web and social network graphs. One of the algorithms employs a partitioning technique using Kmetis tool, and the other employs a clustering technique using Scluster tool. Because clustering algorithms use a similarity measure between each graph node and part...
Estratégias de participação para a optimização da descarga distribuída da Web
Exposto, JoséTese de doutoramento em Informática (ramo de conhecimento em Engenharia de Computadores) ; Face à imensidão de informação na Web, a descarga de páginas utilizada, por exemplo, em motores de pesquisa, sugere a criação de um sistema de agentes distribuídos (robôs) que descarreguem vários servidores em simultâneo. Porém, quando procuramos optimizar os mecanismos de descargas somos confrontados, pela necessidad...
Deploying applications in multi-SAN SMP Clusters (extended version)
Alves, Albano; Pina, António; Rufino, José; Exposto, JoséThe effective exploitation of multi-SAN SMP clusters and the use of generic clusters to support complex information systems require new approaches; multi-SAN SMP clusters introduce new levels of parallelism and traditional environments are mainly used to run scientific computations. In this paper we present a novel approach to the exploitation of clusters that allows integrating in a unique metaphor: the repres...
Estratégias de partição para a optimização da descarga distribuída de Web
Exposto, JoséFace à imensidão de informação na Web, a descarga de páginas utilizada, por exemplo, em motores de pesquisa, sugere a criação de um sistema de agentes distribuídos (robôs) que descarreguem vários servidores em simultâneo. Porém, quando procuramos optimizar os mecanismos de descargas somos confrontados, pela necessidade de obedecer às actuais políticas de delicadeza que obrigam à existência de um intervalo de te...
Shortcut routing for chord graphs in the domus hash space
Rufino, José; Pina, António; Alves, Albano; Exposto, JoséWe present and evaluate shortcut routing algorithms for Chord graphs in the hash space, specifically developed to accelerate distributed lookups in the Distributed Hash Tables (DHTs) of the Domus framework. The algorithms explore our findings about the relation of exponential and euclidean distances in Chord graphs, in conjunction with the availability, in each DHT node, of multiple routing tables of the underlyi...
Efficient partitioning strategies for distributed web crawling
Exposto, José; Macedo, Joaquim; Pina, António; Alves, Albano; Rufino, JoséThis paper presents a multi-objective approach toWeb space partitioning, aimed to improve distributed crawling efficiency. The in- vestigation is supported by the construction of two different weighted graphs. The first is used to model the topological communication infras- tructure between crawlers and Web servers and the second is used to represent the amount of link connections between servers’ pages. The va...
Efficient partitioning strategies for distributed Web crawling
Exposto, José; Macedo, Joaquim; Pina, António Manuel Silva; Alves, Albano Agostinho Gomes; Amaro, José Carlos RufinoThis paper presents a multi-objective approach to Web space partitioning, aimed to improve distributed crawling efficiency. The in- vestigation is supported by the construction of two different weighted graphs. The first is used to model the topological communication infras- tructure between crawlers and Web servers and the second is used to represent the amount of link connections between servers’ pages. The v...
pDomus: a prototype for cluster-oriented distributed hash tables
Rufino, José; Pina, António; Alves, Albano; Exposto, JoséThe Domus architecture for distributed hash tables (DHTs) is specially designed to support the concurrent deployment of multiple and heterogeneous DHTs, in a dynamic shared-all cluster environment. The execution model is compatible with the simultaneous access of several distributed/parallel client applications to the same or different running DHTs. Support to distributed routing and storage is dynamically conf...
Full-speed scalability of the pDomus platform for DHTs
Rufino, José; Pina, António; Alves, Albano; Exposto, José; Lopes, Rui PedroDomus is an architecture for Distributed Hash Tables (DHTs) tailored to a shared-all cluster environment. Domus DHTs build on a (dynamic) set of cluster nodes; each node may perform routing and/or storage tasks, for one or more DHTs, as a function of the node base (static) resources and of its (dynamic) state. Domus DHTs also benefit from a rich set of user-level attributes and operations. pDomus is a prototype...
Domus - an architecture for cluster-oriented distributed Hash tables
Rufino, José; Pina, António; Alves, Albano; Exposto, JoséThis paper presents a high level description of Domus, an architecture for cluster-oriented Distributed hash Tables. As a data management layer, Domus supports the concurrent execution of multiple and heterogeneous DHTs, that may be simultaneously accessed by different distributed/parallel client applications. At system level, a load balancement mechanism allows for the (re)distribution of each DHT over cluster...
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