Spatial P2P and GRIDs

The unprecedented growth and increased importance of geographically distributed data coupled with recent trends of globalization has created a strong need for efficient sharing of data globally. In this regard, P2P systems and GRIDs have revolutionized the world. Incidentally, the performance of such systems is critical to user satisfaction. Hence, we investigate efficient search and effective load-balancing mechanisms (via data migration/replication) for P2P systems and GRIDs. In particular, we are currently exploring issues concerning the feasibility of sharing spatial data in P2P systems. While much work has been done towards expediting search in file-sharing P2P systems, issues concerning spatial indexing in P2P systems are significantly more complicated due to overlaps between spatial objects and the complexity of spatial queries. Incidentally, existing R-tree-based structures for distributed environments (e.g., the MC-Rtree) are not adequate for addressing the sheer scale, dynamism and heterogeneity of P2P environments. Hence, we have proposed the P2PR-tree (Peer-to-Peer R-tree), which is a new spatial index specifically designed for P2P systems. The main features of P2PR-tree are two-fold. First, it is hierarchical and performs efficient pruning of the search space. Second, it is completely decentralized, scalable and robust to peers joining/leaving the system. The main contributions of our load-balancing technique for spatial P2P systems are as follows. First, we propose a dynamic data placement strategy involving data migration and replication, the objective being to provide load-balancing and reduced query response times. Second, we propose a novel technique for load-balancing. Our proposed techniques for P2P systems can also be cost-effectively integrated into GRIDs. Notably, our performance evaluations concerning search and load-balancing in spatial P2P systems and in GRIDs have demonstrated the effectiveness of our methods in reducing user response times significantly.

An overview of our proposal on the P2PR-tree can be found here(MS-PowerPoint), while a summary of our contribution to load-balancing in GRIDs is located here(MS-PowerPoint). If you are interested in further details, please feel free to contact me at anirban@tkl.iis.u-tokyo.ac.jp. My research website is http://www.tkl.iis.u-tokyo.ac.jp/~anirban and my personal website is located at http://www.angelfire.com/dbz/anirban.

(Anirban Mondal)