Maha Abdallah

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Databases are hosted by a growing number of lightweight intelligent devices like palmtops, cellular phones, car computers and even smart cards. Mobility and disconnected computing are two major issues in such environment. This paper deals with the way databases can be exploited in this context while maintaining a strong transactional coherency. More(More)
1 Although widely used in distributed transactional systems, the so-called Two-Phase Commit (2PC) protocol introduces a substantial delay in transaction processing, even in the absence of failures. This has led several researchers to look for alternative commit protocols that minimize the time cost associated with coordination messages and forced log writes(More)
Peer-to-peer (P2P) systems provide a robust, scalable and decentralized way to share and publish data. Although highly efficient, current P2P index structures based on Distributed Hash Tables (DHTs) provide only exact match data lookups. This compromises their use in database applications where more advanced query facilities, such as range queries, are a(More)
—Peer-to-peer (P2P) architectures have become popular for designing scalable virtual environments (VEs) in recent years. However, one question that remains is whether a single overlay can be flexible enough to support different types of VEs. We present S-VON, a P2P overlay that attempts this goal by providing spatial publish / subscribe (SPS) services.(More)
Peer-to-peer (P2P) architectures have recently become a popular design choice for building scalable Networked Virtual Environments (NVEs). In P2P-based NVEs, system and data management is distributed among all participating users. Towards this end, a Delaunay triangulation can be used to provide connectivity between the different NVE users depending on(More)
The current standard in governing distributed transaction termination is the so-called Two-Phase Commit protocol (2PC). The first phase of 2PC is a voting phase, where the participants in the transaction are given an ultimate right to abort that transaction. Giving up that veto right from all participants reduces the overhead of the atomic commitment(More)
Peer-to-peer (P2P) architectures have recently become a popular design choice to build scalable Networked Virtual Environments (NVEs). While P2P architectures offer better scalability than server-based architectures, efficient distribution and management of avatar and object states remains a highly challenging issue. In this paper, we propose GROUP, a(More)
Grid computing technologies provide mechanisms that allow the seamless sharing of distributed and heterogeneous resources, such as supercomputers, storage systems, and data sources, in a large-scale and dynamic environment. Research works in data grids have generally focused on applications where data resources are stored in files. However, many scientific(More)