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This paper presents the most exhaustive study of synchronization to date. We span multiple layers, from hardware cache-coherence protocols up to high-level concurrent software. We do so on different types of architectures, from single-socket -- uniform and non-uniform -- to multi-socket -- directory and broadcast-based -- many-cores. We draw a set of(More)
We introduce "asynchronized concurrency (ASCY)," a paradigm consisting of four complementary programming patterns. ASCY calls for the design of concurrent search data structures (CSDSs) to resemble that of their sequential counterparts. We argue that ASCY leads to implementations which are portably scalable: they scale across different types of hardware(More)
This paper presents a technique for semantic Web service composition inspired by the behavior of ants. The proposed technique combines a service composition graph model with the ant colony optimization met heuristic to select the optimal composition solution. In our approach, we have considered as selection criteria the QoS attributes of the services and(More)
Scaling to a large number of cores with non-uniform communication latency and unpredictable response time may call for viewing a modern many-core architecture as a distributed system. In this view, the cores replicate shared data and ensure consistency among replicas through a message-passing based <i>agreement</i> protocol. In this paper, we present the(More)
The behavior of biological swarms offers us many clues regarding the design of efficient optimization methods applicable in various domains of computer science. Inspired by the behavior of ants, we propose in this paper two methods for semantic Web service discovery and composition. For efficiently discovering the services that will be involved in the(More)
This paper presents a framework for automatic service composition which combines a composition graph model with an Ant Colony Optimization metaheuristic to find the optimal composition solution. The composition graph model encodes all the possible composition solutions that satisfy a user request. The graph will be further used as the search space for the(More)
We argue that there is virtually no practical situation in which one should seek a "theoretically wait-free" algorithm at the expense of a state-of-the-art blocking algorithm in the case of search data structures: blocking algorithms are simple, fast, and can be made "practically wait-free". We draw this conclusion based on the most exhaustive study of(More)