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Workflow mechanism is used into grid system to combine multiple grid services to implement complex grid application. But the workflow is not programmable, and is not flexible enough for users as well. In this paper, a Distributed Programmable Grid System (DPGS) is put forward. In DPGS, a course-grained parallel programming interface GridPPI is implemented. Through it, user could couple multiple web services in DPGS to completed complicated requests. Based on Globus Toolkit 3.9.3, the DPGS provides a simply organized, extendable and scalable grid environment for grid designer to design and deploy traditional or new applications.

The gossip mechanism could support reliable and scalable communication in large-scale settings. In large-scale peer-to-peer environment, however, each node could only have partial knowledge of the group membership. More seriously, because the node has no global knowledge about the underlying topology, gossip mechanism incurs much unnecessary network overhead on the Internet. In this paper, we present Genius, a novel peer-to-peer location-aware gossip. Unlike many previous location-aware techniques which utilize BGP or other router-level topology information, Genius uses the network coordinates map produced by Vivaldi as the underlying topology information. By utilizing the information, Genius could execute near-preferential gossip, that is, the node should be told the gossip message by nodes as close as possible, through which much unnecessary ‘long-range’ communication cost could be reduced. Further, the node direction information inherited in the coordinate space is exploited. We present preliminary experimental results which prove the feasibility of our scheme.

In this paper, a practical coarse-grained distributed parallel programming interface for grid computing (PI4GC) is introduced. It provides a group of generic and abstract function prototypes with well-specified semantics. PI4GC is an MPI-like interface plus high-level parallel tasking over grid. Following its specification, users could couple multiple computing tools distributed over grid to run complex computing problems. We first describe the motivations of PI4GC and related works. Then its specification is put forward in detail. At last, implementation of PI4GC over OGSA is also discussed simply.

Metasearch engines are developed to overcome the shortcoming of single search engine and try to benefit from cooperative decision by combining the results of multiple independent search engines that make use of different models and configurations. In this work, we study the metasearch problem via voting that facilities multiple agents making cooperative decision. We can deem the source search engines as voters and all ranked documents as candidates, then metaseach problem is actually to find a voting algorithm to obtain group’s preferences on these documents(candidates). In addition to two widely discussed classical voting rules: Borda and Condorcet, we study another two voting algorithms, Black and Kemeny. Since Kemeny ranking problem is NP-hard, a new heuristic algorithm has been proposed for metasearch. Some experiments have been carried out on TREC2001 data for evaluating these metasearch algorithms coming from voting.