In this paper we consider the retrieval of variable bit rare (VBR) video from the distributed video sewer Video sewer often employs the constant rate retrieval scheme, in which a fixed amount of disk bandwidth is rese...
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ISBN:
(纸本)0818691948
In this paper we consider the retrieval of variable bit rare (VBR) video from the distributed video sewer Video sewer often employs the constant rate retrieval scheme, in which a fixed amount of disk bandwidth is reserved throughout the retrieval to guarantee the continuous playback requirement. In constant rate retrieval, the allocated disk bandwidth is not always fully utilized in order to avoid excessive prefetch buffer requirement. this results in poor disk bandwidth utilization. We present a novel retrieval algorithm for stored variable bit rate video called piecewise fixed rate retrieval scheme. this scheme divides the total retrieval duration into several intervals during which a constant amount of disk bandwidth is reserved in order to maximize the disk bandwidth utilization. We examine the effectiveness of the retrieval scheme through extensive simulation studies. Compared to existing retrieval schemes, piecewise fixed rate retrieval achieves the great reduction in retrieval rare variability of disk bandwidth allocated and results in high disk bandwidth utilization.
In this paper, we study the exchange of messages among a set of processors linked through an interconnection network. We focus on general, non-unimiform versions of all-to-all (or complete) exchange problems in asynch...
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ISBN:
(纸本)3540648097
In this paper, we study the exchange of messages among a set of processors linked through an interconnection network. We focus on general, non-unimiform versions of all-to-all (or complete) exchange problems in asynchronous systems with a linear cost model and messages of arbitrary sizes. We extend previous complexity results to show that the general asynchronous problems are NP-complete. We present several approximation algorithms and determine which heuristics are best suited to several parallel systems. We conclude with experimental results that show that our algorithms outperform the native all-to-all exchange algorithm on an IBM SP2 when the number of processors is odd.
the need to solve ever-larger transient CFD problems more efficiently and reliably has led to the use of mesh adaptation on distributed memory parallel computers. PTETRAD is a portable parallelisation of a general-pur...
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ISBN:
(纸本)3540648097
the need to solve ever-larger transient CFD problems more efficiently and reliably has led to the use of mesh adaptation on distributed memory parallel computers. PTETRAD is a portable parallelisation of a general-purpose, unstructured, tetrahedral adaptation code. the variation of the tetrahedral mesh density both in space and time gives rise to dynamic load balancing problems that are time-varying in an unpredictable manner. the performance of a C/MPI version of PTETRAD will be demonstrated and the implementation of complex parallel hierarchical data-structures discussed. the need to make coding of such applications easier is addressed through the design of a novel abstract interface. the relationship of this interface to existing software and hardware systems will be described and the performance benefits illustrated by means of an example. the portable implementation of this interface by means of shared abstract data types will be considered.
In this paper, we propose three tree-based parallel load-balancing methods, the MCSTPLB method, the BTPLB method, and the CBTPLB method, to deal withthe load unbalancing problems of solution-adaptive finite element a...
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ISBN:
(纸本)3540648097
In this paper, we propose three tree-based parallel load-balancing methods, the MCSTPLB method, the BTPLB method, and the CBTPLB method, to deal withthe load unbalancing problems of solution-adaptive finite element application programs. To evaluate the performance of the proposed methods, we have implemented those methods along withthree mapping methods, the AE/ORB method, the AE/MC method, and the MLkP method, on an SP2 parallel machine. the experimental results show that (1) ifa mapping method is used for the initial partitioning and this mapping method or a load-balancing method is used in each refinement, the execution time of an application program under a load-balancing method is always shorter than that of the mapping method. (2) the execution time of an application program under the CBTPLB method is better than that of the BTPLB method that is better than that of the MCSTPLB method.
A heuristic distributed algorithm for allocating power among OFDM subchannels is proposed. Its performance and convergence in a multi-cell system with frequency reuse factor 4 are evaluated through simulation. With a ...
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A heuristic distributed algorithm for allocating power among OFDM subchannels is proposed. Its performance and convergence in a multi-cell system with frequency reuse factor 4 are evaluated through simulation. With a realistic simulation which considers uniformly distributed mobiles, propagation loss and fading, it is shown that this simple distributed algorithm enhances the throughput of OFDM systems as compared to equal power allocation.
We present the implementation of an architecture for the distributed control of an omnidirectional mobile robot driven by stepper motors. We have developed the kinematic modelling of such a robot from which control an...
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We present the implementation of an architecture for the distributed control of an omnidirectional mobile robot driven by stepper motors. We have developed the kinematic modelling of such a robot from which control and sensor equations are derived. these relations permit us to map in time, movements with respect to a fixed floor frame into wheels movements, and vice versa. A hierarchical control model has been selected for real time computation of control algorithm and parallel synchronisation of motors movement. It consists on a low cost specific hardware which includes one master processor (a PC) plus three slave microcontrollers (8051).
In this paper we describe the design of a distributed animation system built using the Java language, a parallel Virtual Machine platform, and the World-Wide Web. We focus on two aspects. One is the design of a platfo...
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In this paper we describe the design of a distributed animation system built using the Java language, a parallel Virtual Machine platform, and the World-Wide Web. We focus on two aspects. One is the design of a platform to support distributed 3D animation, the other is the improvement of the efficiency of the parallelcomputing. Due to the collaborative and distributed nature of the Web, the Web browser is integrated withthe distributedcomputing system like a parallel Virtual Machine. the model emphasizes the separation of interface and function. It provides a very friendly and portable interface to manipulate the PVM console and the 3D animation system. To improve the efficiency of the parallelcomputing, we propose a new load balancing strategy, called global distributed control to balance the load in the network processors. the algorithm not only has the ability to dynamically adjust to the load imbalance, but also has the fault tolerance ability. It performs the best when it is compared withthree traditional load balancing schemes. (C) 1997 Elsevier Science B.V.
this paper describes the implementation of a real-time video algorithm on a context-switched FPGA. the FPGA is based on the Xilinx XC4000E FPGA, and includes extensions for dealing with state saving and forwarding and...
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ISBN:
(纸本)0818681594
this paper describes the implementation of a real-time video algorithm on a context-switched FPGA. the FPGA is based on the Xilinx XC4000E FPGA, and includes extensions for dealing with state saving and forwarding and for increased routing demand due to time-multiplexing the hardware. the algorithm makes use of special features of this architecture to achieve high utilization of the silicon at run time. Two configuration planes are programmed as distributed RAM and two planes perform replications of the calculation in parallel. the interplay between the CLB architecture, communication between configuration planes, context-switching overhead, and the end-user application are examined as we map the algorithm onto this architecture.
Modeling the performance behavior of parallel machines is important for compiler support of efficient parallel programming. For parallel machines with a distributed memory organization this includes the simulation of ...
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ISBN:
(纸本)0818677589
Modeling the performance behavior of parallel machines is important for compiler support of efficient parallel programming. For parallel machines with a distributed memory organization this includes the simulation of the communication behavior In this article, we investigate the communication behavior of the Intel Paragon for point-to-point and collective communication operations like single-broadcast and multi-broadcast operations. We derive runtime formulae for these operations that depend on some machine parameters and the message size. Experiments show that the predicted runtimes differ by only a small amount from the measured runtimes.
the proceedings contains 22 papers from the 1997 internationalsymposium on Field Programmable Gate Arrays. Topics discussed include: field programmable gate array (FPGA) architectures;FPGA partitioning and synthesis;...
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the proceedings contains 22 papers from the 1997 internationalsymposium on Field Programmable Gate Arrays. Topics discussed include: field programmable gate array (FPGA) architectures;FPGA partitioning and synthesis;rapid prototyping and emulation;reconfigurable computing;and FPGA floorplanning and routing.
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