Michal Szychowiak

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This paper considers methods for knowledge exploitation in security policies for Service-Oriented Architecture (SOA) environments, discovering the modality conflicts in particular. Two algorithms for discovering SOA-specific modality conflicts are proposed. First, a trivial (ad-hoc) approach is presented and further extended by the improved algorithm which(More)
This paper presents a new technique of recovery for object-based Distributed Shared Memory (DSM) systems. The new technique, integrated with a coherence protocol for atomic consistency model, offers high availability of shared objects in spite of multiple node and communication failures, introducing little overhead. It ensures fast recovery in case of(More)
This paper presents an extended architecture of a policy definition framework fine-tuned for service-oriented environments conforming to the SOA distributed processing paradigm. We establish key requirements for such a framework, and use these to confront existing distributed policy frameworks. We also define a policy language destined to fulfill all(More)
Modern Distributed Shared Memory (DSM) systems offer high speed application processing by allowing to use relaxed consistency models, such as processor consistency. Unfortunately, most of the existing coherence protocols implementing relaxed consistency in multiprocessors or loosely couples clusters use write-update strategy which incurs large communication(More)
This paper describes a checkpointing mechanism destined for Distributed Shared Memory (DSM) systems with speculative prefetching. Speculation is a general technique involving prediction of the future of a computation, namely accesses to shared objects unavailable on the accessing node (read faults). Thanks to such predictions objects can be fetched before(More)
In the mobile environment, weak consistency replication of shared data is the key to obtaining high data availability, good access performance, and good scalability. Therefore new class of consistency models, called session guarantees, recommended for mobile environment, has been introduced. Session guarantees, called also client-centric consistency models,(More)
This paper discusses a way of incorporating speculation techniques into Distributed Shared Memory (DSM) systems with checkpointing mechanism without creating unnecessary checkpoints. Speculation is a general technique involving prediction of the future of a computation, namely accesses to shared objects unavailable on the accessing node (read faults).(More)
This paper presents rVsMR rollback-recovery protocol for distributed mobile systems, guarantying Monotonic Reads consistency model, even in case of server’s failures. The proposed protocol employs known rollback-recovery techniques, however, while applying them, the semantics of session guarantees is taken into account. Consequently, rVsMR protocol is(More)
This paper describes a checkpointing mechanism destined for Distributed Shared Memory (DSM) systems with speculative prefetching. Speculation is a general technique involving prediction of the future of a computation, namely accesses to shared objects unavailable on the accessing node (read faults). Thanks to such predictions objects can be fetched before(More)