A "Consumer Grid" provides the individual-based-counterpart to the organisation-based computational Grid. We describe a Peer-to-Peer system for utilising computational resources on the Grid - extending exist...
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ISBN:
(纸本)076951880X
A "Consumer Grid" provides the individual-based-counterpart to the organisation-based computational Grid. We describe a Peer-to-Peer system for utilising computational resources on the Grid - extending existing work undertaken in systems such as Entropia and SETI@ home. the potential of such a distributed computing resource has been in some ways demonstrated recently by the SETI@home project, having used over 650,000 years of CPU time at the time of writing. A user develops applications within such an environment using a visual workflow system called "Triana" - which automatically generates suitable code for distribution, and can support the user in making placement decisions for their modules. Triana will also be deployed as the workflow enactment engine along withthe Grid Application Toolkit (GAT) within the European GridLab project.
Complex applications need powerful computers to achieve results in a valid time. However, such machines are very expensive and not always available. An alternative is the adoption of several simple, less powerful, and...
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ISBN:
(纸本)9781605585475
Complex applications need powerful computers to achieve results in a valid time. However, such machines are very expensive and not always available. An alternative is the adoption of several simple, less powerful, and less expensive computers, which triggers the need for an adaptable framework that would support parallel and distributed execution in several environments and with different communication protocols. By executing in a heterogeneous environment, the user benefits from a higher number of machines. the framework we propose allows switching from a heterogeneous to a more specialized executing environment, if or when it is available. It supports both newcomers who can use existing default implementations to more quickly create applications of their own, and experienced programmers who, besides using existing framework ions and implementations, can also implement some parts to increase performance. In fact, the main objective is supporting researches, being acceptable to loose some performance when compared to a tailored, and harder to implement solution, still having a better performance when compared to a nonparallel approach. Copyright 2009 ACM.
this paper presents an efficient distributed dynamic channel allocation algorithm for mobile communications systems. the algorithm is based upon the mutual exclusion model, where the channels are grouped by the number...
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ISBN:
(纸本)076950728X
this paper presents an efficient distributed dynamic channel allocation algorithm for mobile communications systems. the algorithm is based upon the mutual exclusion model, where the channels are grouped by the number of cells in a cluster and each group of channels can not be shared concurrently within the cluster. We discuss the algorithm and prove its correctness. We also show that the algorithm requires at most (worst case) O(N-g * N(n)logN(n)) messages, where N-g is the number of groups and N-n is the number of neighbors. this is compared to Choy's algorithm which requires O(N-g(2) * N-n), where N-g is the number of groups. Our simulations experiments indicate that DDRA algorithm outperforms previous schemes. A 5% reduction in the denial rate, and a 10-30% reduction in the acquisition time channel were obtained using our algorithm when compared to previous algorithm.
We introduce DVSA, distributed virtual shared areas, a virtual machine supporting the sharing of information on distributed memory architectures. the shared memory is structured as a set of areas where the size of eac...
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Mixed-parallel applications can take advantage of large-scale computing platforms but scheduling them efficiently on such platforms is challenging. When relying on classic list-scheduling algorithms, the issue of inde...
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ISBN:
(纸本)9781424415595
Mixed-parallel applications can take advantage of large-scale computing platforms but scheduling them efficiently on such platforms is challenging. When relying on classic list-scheduling algorithms, the issue of independent and selfish task allocation determination may arise. Indeed the allocation of the most critical task may lead to poor allocations for subsequent tasks. In this paper we propose a new mixed-parallel scheduling heuristic that takes into account that several tasks may have almost the same level of criticality during the allocation process. We then perform a comparison of this heuristic with other algorithms in simulation over a wide range of application and on platform conditions. We find that our heuristic achieves better performance in terms of schedule length, speedup and degradation from best.
In this work we propose a fault-tolerant mechanism for parallel programs based on task replication. We use a sequential discrete-event simulator of a distributed system subject to failures to compare a semi-active app...
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ISBN:
(纸本)076950728X
In this work we propose a fault-tolerant mechanism for parallel programs based on task replication. We use a sequential discrete-event simulator of a distributed system subject to failures to compare a semi-active approach and a passive approach of the protocol. In our model, each time a task of a given parallel program is allocated, a copy of it is stored in a second processor, called the buddy processor. If the original processor fails, the copies of the tasks at the buddy processor will be processed, providing fault tolerance. Some performance measures, such as program execution times and processor utilization factors, are given for the different versions of the mechanism. the performance has been studied as a function of processor degradation, and program and system sizes.
Gypsy is a component-based, dynamically extensible environment for mobile agent systems. the runtime environment consists of lightweight servers that provide a distributed execution environment for agents, and a remot...
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this paper proposes a novel algorithm for load balancing in the parallel and distributed systems. Firstly, almost all jobs are organized into the standard job combinations, each of which consists of one to four jobs. ...
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ISBN:
(纸本)0769529097
this paper proposes a novel algorithm for load balancing in the parallel and distributed systems. Firstly, almost all jobs are organized into the standard job combinations, each of which consists of one to four jobs. then they are assigned to the machines according to the assignment algorithm for job combinations, which is a special integer partition algorithm. the maximum error between the optimal algorithm and our algorithm is estimated. the experimental results show that our algorithm performs efficiently.
the distributed video coding (DVC) is a new coming video compression technology that utilizes a different computing complexity mode from the traditional video codec. As a new paradigm there are some fundamental and ha...
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ISBN:
(纸本)0769529097
the distributed video coding (DVC) is a new coming video compression technology that utilizes a different computing complexity mode from the traditional video codec. As a new paradigm there are some fundamental and hard questions in DVC that are not sufficiently addressed, for example the complexity balance between DVC encoder and decoder. this will be an important factor for some promising real time applications. In this context, this paper studies the factors which affect the decoding complexities of turbo code based DVC especially focuses on quantization, side information and turbo code bit rates. Analyzing and simulation results show that precise side information will decrease the turbo decoding complexity, large reductions in computations can be traded against relatively small increases in bit rate, and uniform quantizer possesses the advantage than the non-uniform quantizer in computation load at a expense of a little decrease in rate distortion performance.
the proceedings contain 7 papers. the topics discussed include: robust record-replay with processor extraction;debugging support tool for MCAPI applications;detection of transactional memory anomalies using static ana...
ISBN:
(纸本)9781450301367
the proceedings contain 7 papers. the topics discussed include: robust record-replay with processor extraction;debugging support tool for MCAPI applications;detection of transactional memory anomalies using static analysis;unit testing for concurrent business code;a platform for search-based testing of concurrent software;profiling of real-world web applications;and open virtualization framework for testing ground systems.
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