Decentralized and unstructured peer-to-peer applications such as Gnutella are attractive because they require no centralized directories and no precise control over network topology or data placement. Search algorithm...Decentralized and unstructured peer-to-peer applications such as Gnutella are attractive because they require no centralized directories and no precise control over network topology or data placement. Search algorithm is the major component of the distributed system and its efficiency also does influence the systems performance. However the flooding-based query algorithm used in Gnutella produces huge traffic and does not scale well. Gnutella-like P2P topology has power-law characteristic, so a search algorithm was proposed based on high degree nodes of power-law network, High Degree Nodes-Based Search （HDNBS）. Extensive simulation results show that this algorithm performs on power-law networks very well, achieves almost 100% success rates, produces O（logN） messages per query and can locate target file within O（lagN） hops.展开更多
This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations th...This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations the service intends to perform. When all of the services can be recognized by their roles, the appropriate services can be selected. Based on the interaction policy, a role-based interaction model not only facilitates access control, but also offers flexible interaction mechanism for adapting service-oriented applications. This interaction model adopts programmable reactive tuple space to facilitate context-dependent coordination.展开更多
文摘Decentralized and unstructured peer-to-peer applications such as Gnutella are attractive because they require no centralized directories and no precise control over network topology or data placement. Search algorithm is the major component of the distributed system and its efficiency also does influence the systems performance. However the flooding-based query algorithm used in Gnutella produces huge traffic and does not scale well. Gnutella-like P2P topology has power-law characteristic, so a search algorithm was proposed based on high degree nodes of power-law network, High Degree Nodes-Based Search （HDNBS）. Extensive simulation results show that this algorithm performs on power-law networks very well, achieves almost 100% success rates, produces O（logN） messages per query and can locate target file within O（lagN） hops.
文摘This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations the service intends to perform. When all of the services can be recognized by their roles, the appropriate services can be selected. Based on the interaction policy, a role-based interaction model not only facilitates access control, but also offers flexible interaction mechanism for adapting service-oriented applications. This interaction model adopts programmable reactive tuple space to facilitate context-dependent coordination.
