One of the barriers that prevents the expansion and adoption of Grid technologies is the lack of a standard programming paradigm to port existing applications among different environments. The distributed Resource Man...
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parallel database systems are capable of providing significant performance gains in terms of transaction processing rates. These gains are realized by running many transactions concurrently. A requirement in real-time...
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ISBN:
(纸本)0769521320
parallel database systems are capable of providing significant performance gains in terms of transaction processing rates. These gains are realized by running many transactions concurrently. A requirement in real-time transaction scheduling is to complete the transactions within their deadline. Due to its simplicity, two-phase locking (2PL) is one of the most commonly used concurrency control mechanism. Two alternative methods of securing locks in the 2PL protocol are static locking or dynamic locking. We report performance of the two locking variants of the 2PL protocol under various degrees of resource and data contention in a real-time parallel database system.
Modelling and simulation permeate all areas of business, science and engineering and increasingly complex simulation systems often require huge computing resources and data sets that are geographically distributed. Th...
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Nonlocking multistage interconnection networks are favored to be used as switching networks whenever possible. Crosstalk-free requirement in photonic networks adds a new dimension of constraints for nonblockingness. R...
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ISBN:
(纸本)0769521320
Nonlocking multistage interconnection networks are favored to be used as switching networks whenever possible. Crosstalk-free requirement in photonic networks adds a new dimension of constraints for nonblockingness. Routing algorithms play a fundamental role in nonlocking networks, and any algorithm that requires more than linear time would be considered too slow for real-time applications. One remedy is to use multiple processors to route connections in parallel. In this paper, we study the connection capacity of a class of rearrangeable nonlocking and strictly nonlocking networks with/without crosstalk-free constraint, model their routing problems as weak or strong edge colorings of bipartite graphs, and propose efficient routing algorithms for these networks using parallelprocessing techniques.
This paper gives an overview of the material to be discussed in the invited keynote presentation by H. J. Siegel;it summarizes our research in [1]. Performing computing and communication tasks on parallel and distribu...
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In this paper, we consider the task allocation problem for computing a large set of equal-sized independent tasks on heterogeneous computing systems. This problem represents the computation paradigm for a wide range o...
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ISBN:
(纸本)0769521320
In this paper, we consider the task allocation problem for computing a large set of equal-sized independent tasks on heterogeneous computing systems. This problem represents the computation paradigm for a wide range of applications such as SETI@home and Monte Carlo simulations. We consider a general problem in which the interconnection between the nodes is modeled using a graph. We maximize the throughput of the system by using an extended network flow representation. We then develop a decentralized adaptive algorithm. This algorithm leads to a simple decentralized protocol that coordinates the resources in the system. The effectiveness of the proposed task allocation approach is verified through simulations.
In studying or designing parallel and distributed systems one should have available a robust analytical model that includes the major parameters that determine the system performance. Jackson networks have been very s...
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ISBN:
(纸本)0769521320
In studying or designing parallel and distributed systems one should have available a robust analytical model that includes the major parameters that determine the system performance. Jackson networks have been very successful in modeling parallel and distributed systems. However, they have their limitations. In particular, the product-form solution of Jackson networks assumes steady state and exponential service centers or certain specialized queueing disciplines. In this paper, we use a transient model studying distributed systems with finite workload (no new arrivals). Using some nonexponential distributions we show to what extent the exponential distribution can be used to approximate other distributions. When the number of tasks to be executed is large enough, the model approaches the product-form solution in those cases where the Jackson networks can be applied. We also study some cases where Jackson networks can't be applied (the nonexponential servers have queueing). The model can be used for reliability analysis of systems that allow failures without repair (fail-stop).
distributed shared memory (DSM) is one of the main abstraction to implement data-centric information exchanges among a set of processes. Ensuring causal consistency means all operations executed at each process will b...
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ISBN:
(纸本)0769521320
distributed shared memory (DSM) is one of the main abstraction to implement data-centric information exchanges among a set of processes. Ensuring causal consistency means all operations executed at each process will be compliant to a cause effect relation. This paper first provides an optimality criterion for a protocol P that enforces causal consistency on a DSM. This criterion addresses the number of write operations delayed by P (write delay optimality). Then we present a protocol which is optimal with respect to write delay optimality and we show how previous protocols presented in the literature are not optimal with respect to such a criterion.
Real-Time Corba and minimumCORBA are the foundations many so called distributed real-time embedded (DRE) systems are built upon. These specifications describe middleware suitable for connecting different parts of a co...
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ISBN:
(纸本)0769521320
Real-Time Corba and minimumCORBA are the foundations many so called distributed real-time embedded (DRE) systems are built upon. These specifications describe middleware suitable for connecting different parts of a complex embedded system. Efficient group based communication in such a system can be achieved by using the Event Service. This article focuses on the design of such a service complying to the OMG Event Service standard. It is optimised for the CAN bus, a widely used interconnect, where real-time characteristics are a requirement. A new protocol for the efficient distribution of events in a CAN-based distributed control system is presented, a protocol which is tailored to the CAN bus and produces very low overhead by utilising CAN-specific features.
Power control is an important issue in wireless networks, which still has no satisfactory solution. Due to the limited amount of power available to wireless units, there is a need for systems that operate with reduced...
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ISBN:
(纸本)0769521320
Power control is an important issue in wireless networks, which still has no satisfactory solution. Due to the limited amount of power available to wireless units, there is a need for systems that operate with reduced power consumption levels. We propose a new model for the problem, that exploits the relationship among necessary power and reach of broadcast. The resulting model is called the power control problem in ad hoc networks (PCADHOC). We derive a linear integer programming model, which is used to find lower bounds on the amount of required power. The constraints of the problem guarantee that all required transmissions can be successfully performed. A distributed algorithm based on variable neighborhood search is proposed to solve the PCADHOC. The results of experiments with the algorithm show that the power savings are considerable.
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