Most literature on consecutive-k-out-of-n:F systems gives recursive equations for computing the system reliability. This paper gives a formula for computing the system reliability directly. Using this formula, the sys...
详细信息
Most literature on consecutive-k-out-of-n:F systems gives recursive equations for computing the system reliability. This paper gives a formula for computing the system reliability directly. Using this formula, the system failure distribution is derived. Upper and lower bounds for the system reliability or the system failure distribution are given. Some numerical examples are included.
Adapting applications to each other requires mapping between the concepts, functions, or data native to each application, and identifying the abstractions under which each application can perform correctly and efficie...
详细信息
Adapting applications to each other requires mapping between the concepts, functions, or data native to each application, and identifying the abstractions under which each application can perform correctly and efficiently. Determining appropriate abstractions at any level is never easy, but doing so is critical to an application?s utility and success.
The communication complexity of a linear transformation is the number of scalars which must be transferred between two processors, each of which holds half the input vector in order to perform the transformation such ...
详细信息
The communication complexity of a linear transformation is the number of scalars which must be transferred between two processors, each of which holds half the input vector in order to perform the transformation such that each processor holds half the output vector, This letter shows that the communication complexity of the the discrete Fourier transform of size n is at most n/2, That is, given a suitable partition of the input and output vectors, only n/4 complex numbers must be sent in each direction. In contrast, fast Fourier transform (FFT) algorithms transfer at least n/2 complex numbers in each direction.
This paper describes a technique for calculating the multichannel loading of telephone carrier systems. The approach described is designed to exploit the modern computer more effectively while, at the same time, avoid...
详细信息
This paper describes a technique for calculating the multichannel loading of telephone carrier systems. The approach described is designed to exploit the modern computer more effectively while, at the same time, avoiding some of the weaknesses encountered in previous calculations, namely: (1) the dependence on a "multichannel peak factor" (MCPF), which is established experimentally by partially justified methods (2) the addition of a MCPF for a fixed number of channels to the multichannel equivalent-level distribution (1 percent point) to obtain the instantaneous multichannel peak value. Ideally, this MCPF should be allowed to vary simultaneously with the channel activity and other variables. A further advantage, in the approach submitted here, is that the results obtained contain additional information, derived from the fact that the multichannel load is given in terms of a distribution of peaks with specified probability values. This information is required when dealing with overload and near-linear distortion noise analysis, or in studies involving PCM companding laws. Briefly, the method used is to derive a probability distribution function which describes the amplitude characteristic of multichannel signals as functions of the number of channels in the system. Two basic sets of data are used: (1) the channel activity (2) the instantaneous amplitude probability distribution for an active channel. This information is used in conjunction with the Monte Carlo sampling technique to simulate the instantaneous amplitude from the multichannel signal. This simulation process, incorporated into a computer program, provides a means of generating samples and, by using a sufficient number of samples, a probability distribution is obtained to describe the multichannel loading.
It is well known that the average case deterministic communication complexity is bounded below by an entropic quantity, which one would now call deterministic information complexity. In this paper we show a correspond...
详细信息
It is well known that the average case deterministic communication complexity is bounded below by an entropic quantity, which one would now call deterministic information complexity. In this paper we show a corresponding upper bound. We also improve known lower bounds for the public coin Las Vegas communication complexity by a constant factor. (c) 2006 Elsevier B.V. All rights reserved.
In this paper the problem of electron injection from silicon into silicon dioxide is tackled by means of a physical approach based on a simple model that provides good agreement with experimental data for MOS structur...
详细信息
In this paper the problem of electron injection from silicon into silicon dioxide is tackled by means of a physical approach based on a simple model that provides good agreement with experimental data for MOS structures. The model implements the calculation of the electron energy distribution at the Si-SiO2 interface by means of an efficient nonlocal algorithm, thus making possible a consistent treatment of the tunneling of hot electrons across the oxide. The oxide-field dependence of electron injection is addressed and the relationship between barrier lowering and electron energy distributions is discussed.
This paper investigates the problem of finding an optimal static pessimistic replica control scheme. It has been widely accepted that coteries (proposed by Garcia-Molina and Barbara) provide the most general framework...
详细信息
This paper investigates the problem of finding an optimal static pessimistic replica control scheme. It has been widely accepted that coteries (proposed by Garcia-Molina and Barbara) provide the most general framework for such schemes. We demonstrate that voting schemes, a very small subset of static pessimistic schemes, are optimal for fully connected networks with negligible link failure rates, as well as for Ethernet systems. We also show that voting is not optimal for somewhat more general systems. We propose a modification of the algorithm of Tong and Kain for computing optimal voting in operation independent case, so that it runs in linear (rather than exponential) time. Finally, we propose the first efficient algorithm for computing the optimal vote assignment and appropriate thresholds for fully connected networks when relative frequencies of read and write operations are known. We also extend this result to Ethernet systems.
Scheduling precedence constrained task graphs, with or without duplication, is one of the most challenging NP-complete problems in parallel and distributed computing systems. Duplication heuristics are more effective,...
详细信息
Scheduling precedence constrained task graphs, with or without duplication, is one of the most challenging NP-complete problems in parallel and distributed computing systems. Duplication heuristics are more effective, in general, for fine grain tasks graphs and for networks with high communication latencies. However, most of the available duplication algorithms are designed under the assumption of unbounded availability of fully connected processors, and lie in high complexity range. Low complexity optimal duplication algorithms work under restricted cost and/or shape parameters for the task graphs. Further, the required number of processors grows in proportion to the task-graph size significantly. An improved duplication strategy is proposed that works for arbitrary task graphs, with a limited number of interconnection-constrained processors. Unlike most other algorithms that replicate all possible parents/ancestors of a given task, the proposed algorithm tends to avoid redundant duplications and duplicates the nodes selectively, only if it helps in improving the performance. This results in lower duplications and also lower time and space complexity. Simulation results are presented for clique and an interconnection-constrained network topology with random and regular benchmark task graph suites, representing a variety of parallel numerical applications. Performance, in terms of normalized schedule length and efficiency, is compared with some of the well-known and recently proposed algorithms. The suggested algorithm turns out to be most efficient, as it generates better or comparable schedules with remarkably less processor consumption.
This paper presents the process, strategy, and results associated with porting a typical combustion physics flow solver to current state-of-the-art and future massively-parallel computer architectures. Major focus is ...
详细信息
This paper presents the process, strategy, and results associated with porting a typical combustion physics flow solver to current state-of-the-art and future massively-parallel computer architectures. Major focus is placed on the distinct algorithmic structure of these types of codes and how it can be integrated with modern programming paradigms for heterogeneous platforms (i.e., distributed many-core systems with accelerators). An end-to-end case study is presented that exemplifies the process in a generic manner, which then serves as a clear guide with respect to the strategy and best practices leading to a robust and adaptable framework that performs well, is durable over time, is portable, and requires minimal human-effort. This end is accom-plished beginning with the use of a mature, validated, structured, multiblock code framework optimized for application of both Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS). This code has been ported to a variety of platforms over the past decade, including most recently the Oak Ridge Leader-ship computing Facility's "Summit" Platform. The experience gained on these multiple platforms provides general insights and thus the results presented are not specific to any one code or platform other than the overarching trend toward distributed many-core systems with accelerators in order to move toward exascale performance. The resultant performance and scalability of the ported code is demonstrated on a real-world application;a state-of-the-art rotating detonation rocket engine simulation that matches the complex geom-etry and boundary conditions imposed as part of a companion experimental campaign.
暂无评论