Results 261 to 270 of about 8,384 (311)
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Proceedings IEEE Virtual Reality (Cat. No. 99CB36316), 2003
This paper is concerned with the concurrency control for collaborative virtual environments. In particular, we describe how concurrent actions are coordinated in a multi-user, large-scale 3-D layout system CIAO. In contrast to many existing systems that sacrifice responsiveness in order to maintain consistency, CIAO achieves optimal response and ...
Un-Jae Sung +2 more
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This paper is concerned with the concurrency control for collaborative virtual environments. In particular, we describe how concurrent actions are coordinated in a multi-user, large-scale 3-D layout system CIAO. In contrast to many existing systems that sacrifice responsiveness in order to maintain consistency, CIAO achieves optimal response and ...
Un-Jae Sung +2 more
openaire +1 more source
On Concurrency Control by Multiple Versions
ACM Transactions on Database Systems, 1982We examine the problem of concurrency control when the database management system supports multiple versions of the data. We characterize the limit of the parallelism achievable by the multiversion approach and demonstrate the resulting space-parallelism trade-off.
Christos H. Papadimitriou +1 more
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The Computer Journal, 2001
Summary: Serializability as an isolation criterion, though well suitable for traditional transactions, would overly restrict the concurrency of long lasting activities such as workflows. By using semantic information it is possible to weaken, or give up altogether, the serializability criterion and yet ensure workflow execution correctness. The problem,
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Summary: Serializability as an isolation criterion, though well suitable for traditional transactions, would overly restrict the concurrency of long lasting activities such as workflows. By using semantic information it is possible to weaken, or give up altogether, the serializability criterion and yet ensure workflow execution correctness. The problem,
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Concurrency Control by Locking
SIAM Journal on Computing, 1983We present a geometric method for studying concurrency control by locking. When there are only two transactions, our method yields an exact characterization of safe locking policies and also of deadlock-free locking policies. Our results can be extended to more than two transactions, but in that case the problem becomes NP-complete.
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The Complexity of Reliable Concurrency Control
SIAM Journal on Computing, 1985Summary: We define what it means for a schedule to be reliable, that is, correct in the face of possible transaction failures (assuming that aborting a transaction to restore correctness is not allowed). It turns out that the right definition is recursive, and surprisingly involved.
Christos H. Papadimitriou +1 more
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The Complexity of Distributed Concurrency Control
SIAM Journal on Computing, 1981We present a formal framework for distributed databases, and we study the complexity of the concurrency control problem in this framework. Our transactions are partially ordered sets of actions, as opposed to the straight-line programs of the centralized case. The concurrency control algorithm, or scheduler, is itself a distributed program.
Paris C. Kanellakis +1 more
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Concurrent checking in dedicated controllers
Proceedings 1989 IEEE International Conference on Computer Design: VLSI in Computers and Processors, 2003A novel method for introducing online test facilities in a controller with a very low overhead is presented. This online test consists of detecting illegal paths in the control flow graph. These illegal paths may be due to either permanent faults or transient errors.
Régis Leveugle, Gabriele Saucier
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Cooperative concurrency control on the Web
Proceedings of the Sixth IEEE Computer Society Workshop on Future Trends of Distributed Computing Systems, 2002Sharing of data in collaborative environments requires mechanisms that ensure the consistency of data in spite of concurrency and failures. This is traditionally handled by transactions or extended transaction mechanisms. The World Wide Web, although originally designed as an information storage and retrieval system, is being extended to serve as a ...
Michael Mock +2 more
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Concurrent control with “readers” and “writers”
Communications of the ACM, 1971The problem of the mutual exclusion of several independent processes from simultaneous access to a “critical section” is discussed for the case where there are two distinct classes of processes known as “readers” and “writers.” The “readers” may share the section with each other, but the “writers” must have exclusive access. Two solutions are presented:
Pierre-Jacques Courtois +2 more
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Concurrency control performance in DAYS
Proceedings of the 3rd ACM international workshop on Data engineering for wireless and mobile access, 2003Through the use of broadcast, data may be retrieved by wireless users in an efficient manner. In this paper, we provide a description of our architecture, DAYS, which is designed to provide a flexible broadcast environment which allows clients to update the content of the broadcast.
Ahmad S. Al-Mogren, Margaret H. Dunham
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