An algorithm that integrates real-time scheduling with replication control is presented. the algorithm adopts a token-based scheme for replication control and attempts to balance the urgency of real-time transactions ...
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An algorithm that integrates real-time scheduling with replication control is presented. the algorithm adopts a token-based scheme for replication control and attempts to balance the urgency of real-time transactions withthe conflict resolution policies. In addition, the algorithm employs epsilon-serializability (ESR), a correctness criterion that is less stringent than conventional one-copy serializability. the algorithm is flexible and very practical, since no prior knowledge of data requirements or execution time of each transaction is required.< >
A protocol for controlling a client-server interaction that can exploit underutilized local-area-network (LAN)-based computing resources is discussed. A queuing simulation is used to assess the impact of three sizes o...
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A protocol for controlling a client-server interaction that can exploit underutilized local-area-network (LAN)-based computing resources is discussed. A queuing simulation is used to assess the impact of three sizes of task chunk and two variations of task mix within those chunks in two different LAN environments. the practicality of the protocol in an executive information system or decision support system (EIS/DSS) environment is verified using results of a prototype implementation.< >
A simple model of asynchronous distributed communication, the process-to-channel/sub agent/-to-process (PCP) model, is presented. this model is used as a framework for presenting channel grammars that specify channel ...
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A simple model of asynchronous distributed communication, the process-to-channel/sub agent/-to-process (PCP) model, is presented. this model is used as a framework for presenting channel grammars that specify channel behavior. the PCP model, in conjunction with channel grammars, provides a versatile and succinct mechanism for specifying and comparing different types of channels, as well as for designing channel implementations. the usefulness of these tools is demonstrated by presenting an implementation of hierarchical F-channels, which are channels based on hierarchical communication speeds and F-channels.< >
A multi-language-based data interface system for heterogeneous distributed processing is introduced. A prototyped environment based on this system is discussed, and an evaluation of the prototyped system is presented....
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A multi-language-based data interface system for heterogeneous distributed processing is introduced. A prototyped environment based on this system is discussed, and an evaluation of the prototyped system is presented. It is shown that by keeping the syntax of the specification language flexible and close to existing high-level languages, a user can learn the interface language quickly. Semantically, this data interface views structured data as consisting of two parts: the data values themselves and the representation of the structure among the data values. through this separation, it is possible to have pipelined data type checking and data conversion operations.< >
In a real-time database system, it is difficult to meet all timing constraints due to the consistency requirements of the underlying database. Real-time database transaction scheduling requires the development of effi...
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In a real-time database system, it is difficult to meet all timing constraints due to the consistency requirements of the underlying database. Real-time database transaction scheduling requires the development of efficient concurrency control protocols that try to maximize the number of transactions satisfying their real-time constraints. Several distributed, lock-based, real-time, concurrency control protocols are described. the relative performance of the protocols in a nonreplicated database environment is reported. the protocols take the real-time requirements of the transactions into account in ordering data accesses, while maintaining data consistency by enforcing serializability.< >
A distributed mutual exclusion algorithm based on Huffmann trees is described. A request message is passed from a leaf node all the way to the root, signaling that a node is allowed to enter the critical section. Faul...
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A distributed mutual exclusion algorithm based on Huffmann trees is described. A request message is passed from a leaf node all the way to the root, signaling that a node is allowed to enter the critical section. Fault tolerance is achieved by forming the Huffman tree dynamically. It is shown that the approach has broad applications in distributedsystems where nodes are often organized as a logical tree for ease of coordination. High fault tolerance is achieved, since a faulty node can be detected by its neighbor and thus be deleted from the tree.< >
Flush channels generalize more conventional asynchronous message passing protocols. A distributed system that uses flush channels allows a programmer the flexibility of specifying the delivery order of each message in...
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Flush channels generalize more conventional asynchronous message passing protocols. A distributed system that uses flush channels allows a programmer the flexibility of specifying the delivery order of each message in relation to other messages transmitted on the channel. An implementation technique that follows directly from a verification methodology for flush channels is presented. A relatively formal argument in support of the technique is included.< >
An approach to analyzing self-stabilization based on the finite-state machine model is presented. A finite-state machine is used to model the behavior of each node in a distributed system. when the self-stabilizing al...
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An approach to analyzing self-stabilization based on the finite-state machine model is presented. A finite-state machine is used to model the behavior of each node in a distributed system. when the self-stabilizing algorithms are applied. the approach is useful for analyzing the correctness of self-stabilizing algorithms and their time complexity. A self-stabilizing algorithm for finding maximal matching is used as an example to show how the finite-state machine model is applied. A simpler proof for the correctness and an upper bound of the time complexity tighter than the one proved by a variant function are attained.< >
distributed wait-depth-limited (DWDL) concurrency control, a locking-based method that limits the wait-depth of blocked transactions to one, which assures that deadlocks are resolved as part of regular transaction pro...
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distributed wait-depth-limited (DWDL) concurrency control, a locking-based method that limits the wait-depth of blocked transactions to one, which assures that deadlocks are resolved as part of regular transaction processing is described. the performance of DWDL is compared withthat of distributed two-phase locking (2PL) and the wound-wait concurrency control method through a detailed simulated. Results show that DWDL behaves similarly to 2PL for low data contention levels, but at high lock contention levels, DWDL outperforms the other methods to a significant degree.< >
the partition-and-replicate-strategy (PRS) algorithm for distributed query processing is evaluated and its performance is validated. Although in principle PRS is better than single-site processing, early experimental ...
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the partition-and-replicate-strategy (PRS) algorithm for distributed query processing is evaluated and its performance is validated. Although in principle PRS is better than single-site processing, early experimental results indicate the contrary. based on experimental results, the factor which causes performance deterioration is identified and a remedy is provided. As a result, it is shown that the PRS strategy outperforms single-site processing in a realistic environment and that various parameters, such as the number of processing sites, partitioning speed relative to join speed, and sizes of the join relations, affect the performance of the PRS strategy significantly. Among these parameters, the algorithm is most sensitive to the partition speed.< >
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