We are developing a task parallel script language named MegaScript for mega-scale parallel processing. MegaScript regards sequential/parallel programs as tasks, and controls them for massively parallel execution. Alth...
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ISBN:
(纸本)9780889867048
We are developing a task parallel script language named MegaScript for mega-scale parallel processing. MegaScript regards sequential/parallel programs as tasks, and controls them for massively parallel execution. Although MegaScript programs require optimizations and extensions specific to the application and the computing environment, modifying the runtime system or task programs greatly reduces portability and reusability. To satisfy these conflicting requirements, we propose a user-level dynamic extension scheme named Adapter. In this scheme, the user defines a customization code and hooks to it a specific event. the runtime system calls back the code for the event locally, enabling it to extend or optimize system behavior without modifying the runtime or task programs. the results of our evaluation of the scheme show that the overhead and programming cost are both small enough for practical use.
We report here a backscattering model of average signal power function (SPF) for laser radar 3D range imagery obtained by arrays of detectors for arbitrary coarse targets. the model relates the average power seen by t...
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ISBN:
(纸本)9781467345651;9780769549033
We report here a backscattering model of average signal power function (SPF) for laser radar 3D range imagery obtained by arrays of detectors for arbitrary coarse targets. the model relates the average power seen by the receiver with laser pulse, target shape, optical scattering properties of surface material, incidence angle and other factors. the optical scattering property of the material is characterized by bidirectional reflectance distribution function (BRDF). the model can be used for demonstration of 3D laser radar system and can also be used to generate library of model data sets for automatic target recognition (ATR). Finally, Compute Unified Device Architecture (CUDA) is introduced for parallelizing these algorithms. the acceleration reaches 56 times speedup on single Fermi-generation NVIDIA GTX 480 as compared to the traditional CPU version of code on Intel i7 930 CPU.
this paper presents a concept called virtual clusters (VCs) to allocate resources for an application from a computing utility with a geographically distributed resource base. the VC creation process is modeled as a fa...
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this paper presents a concept called virtual clusters (VCs) to allocate resources for an application from a computing utility with a geographically distributed resource base. the VC creation process is modeled as a facility location problem and an efficient heuristic is devised to solve it. We extend the model to include an "overload partition" to a VC such that demand surges can be efficiently handled. Extensive simulations have been conducted to examine the performance of VCs under different scenarios and to compare it with a fully dynamic scheme called the Service Grid. the results indicate that VC is more cost-effective and robust than Service Grid.
this paper describes a general technique to identify control flow errors in parallel programs, which can be automated into a compiler. the compiler builds a system of linear equations that describes the global control...
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this paper describes a general technique to identify control flow errors in parallel programs, which can be automated into a compiler. the compiler builds a system of linear equations that describes the global control flow of the whole program. Solving these equations using standard techniques of linear algebra can locate a wide range of control flow bugs at compile time. this paper also describes an implementation of this control flow analysis technique in a prototype compiler for a well-known parallel programming language. In contrast to previous research in automated parallel program analysis, our technique is efficient for large programs, and does not limit the range of language features.
As information systems develop into larger and more complex implementations, the need for survivability increases. When components are exported from a remote system to a local system under different administrative set...
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ISBN:
(纸本)9780889867741
As information systems develop into larger and more complex implementations, the need for survivability increases. When components are exported from a remote system to a local system under different administrative settings and deployed in different environments we have to guarantee the proper execution of those remote components in the currently working environment because the remote components may have failures or malicious codes that can affect the local computing environment. In this paper, we address a multiple-aspect testing approach, which is able to increase the possibility of detecting a fault in a component by having various ways possible to conduct the test on the components. We have implemented a prototype that provides for the multiple-aspect testing for the downloaded components in runtime without access to the source code. Finally, the implementation of the multiple-aspect testing is evaluated and analyzed in terms of detection performance and accuracy.
We compare parallel algorithms for random permutation generation on symmetric multiprocessors (SMPs). Algorithms considered are the sorting-based algorithm, Anderson’s shuffling algorithm, the dart-throwing algorithm...
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Speculative Locking protocol (SL) is a concurrency control protocol that allows for parallel execution of conflicting transactions through a method of multilevel lending and versioning. the SL protocol shows performan...
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ISBN:
(纸本)9780889867048
Speculative Locking protocol (SL) is a concurrency control protocol that allows for parallel execution of conflicting transactions through a method of multilevel lending and versioning. the SL protocol shows performance improvements over the standard two-phase locking (2PL) protocol, but relies on several assumptions that would make it unsuitable in real-world scenarios. In this paper, we have proposed an adaptive speculative locking (ASL) protocol that improves performance of real-time distributed database systems by augmenting the SL protocol with four features: distributed real-time database system support;simultaneous multi-threading or page execution;control of transaction execution through transaction queue management;and restricting system memory through the use of virtual memory. the simulation results demonstrate the superiority of the ASL protocol over the SL protocols through the reduction of data contention caused by finite memory and the overall increase in transaction throughput.
To achieve good parallel efficiency, applications using structured adaptive mesh refinement (SAMR) need to repeatedly repartition and redistribute the underlying dynamic grid hierarchy. However, no single partitioner ...
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ISBN:
(纸本)9780889867741
To achieve good parallel efficiency, applications using structured adaptive mesh refinement (SAMR) need to repeatedly repartition and redistribute the underlying dynamic grid hierarchy. However, no single partitioner works well for all application and computer states. this paper presents the implementation and evaluation of a patch-based partitioner for SAMR grid hierarchies. the partitioner results in a good and stable load balance, on average 3.1%. Space-filling curves are used to reduce the high communication volumes that are inherent in this type of partitioner. the partitioner will be a part of the Meta-Partitioner, a partitioning framework that automatically selects, configures and invokes good-performing partitioners for general SAMR applications. Access to a large number of complementing partitioners is essential for the Meta-Partitioner. the presented partitioner will help to significantly decrease run-times for SAMR applications where load balance is the main priority.
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