异构并行工作站机群系统的性能评价指标

文中在对矩阵乘法进行实验研究的基础上，分析了异构性对工作站机群系统性能的影响，描述了异构性的数学模型，扩展了加速比和效率等性能指标的定义，使之能同时适用于同构，异构两种并行系统的性能评价。     

Simple authentication

This paper describes a simple authentication protocol for use with terminal emulation programs running on small workstations, and communicating with a host computer over a (potentially) insecure network. The technique has the advantage that it requires no more network traffic than would be necessary using a standard user-id/password challenge, and also requires only a small amount of additional intelligence at the workstation. Some management issues are also discussed. The system has been implemented on two host systems and two workstation types.     

ARCNET网络下数据采集的设计与实现

ARCNET的可靠、高速及稳定的性能已在许多工业领域应用，成为工业自动化领域的重要部分。然而计算机管理信息系统所使用的PC机或工作站所处的网络环境一般采用的是以太网。ARCNET网上的一些设备状态信息、生产信息需要提供给上层管理信息系统，这筑需要把ARCNET网上的数据采集到基于以太网的工作站上。在这一需求下，对如何将ARCNET网上的信息传送给以太网进行了研究，并实现了在这一异构网环境下的数据采集。     

A concurrent network architecture for cost-efficient parallel computing using workstation clusters

Within the past few years, workstation clusters have gained an increasing importance as platforms for parallel high-performance simulation problems. In contrast to the specialized and cost-intensive interconnection network of distributed memory multiprocessor systems, workstation clusters utilize local area networks (LANs) and common communication protocols. Therefore, the cost-efficiency of workstation clusters for parallel tasks is high while the communication performance is limited compared to parallel computer systems. To improve the communication performance of clusters, new protocols can be applied as well as specialized interconnection networks. On one hand, these solutions decrease the cost-efficiency of clusters, while on the other hand the performance of local area networks is increasing because of new technologies such as FastEthernet, GigaEthernet or ATM. In this contribution, we propose increasing the communication performance of clusters through the concurrent network architecture (CNA) with multi-channel communication systems. Through the use of parallel and independent LANs, the communication performance of a cluster can be improved while maintaining the cost-efficiency of the wide-spread LAN technology and protocols. This paper gives an overview of the CNA, the requirements of an implementation and a performance evaluation of a CNA workstation cluster.     

Performance analysis of assembly systems with highlift stations: a practical approach

One common problem associated with automatic assembly systems is that some assembly operations may have relatively long cycle times. As a consequence, the productivity, as determined by the operations with the longest cycle time, can be significantly reduced. Therefore, a special form of parallel workstation known as a highlift station was developed to improve the performance of an automatic assembly system. In this paper, we present a simple analytical model that can help engineers to estimate the performance of highlift stations. This model is particularly useful at the design stage, as only approximate results are necessary for selecting the configuration.     

Parallel Algorithm Design on Some Distributed Systems

Some testing results on DAWINING-1000,Paragon and workstation cluster are described in this paper.On the home-made parallel system DAWNING-1000 with 32 computational processors,the practical performance of 1.1777 Gflops and 1.58 Gflops has been measured in solving a dense linear system and doing matrix multiplication,respectively .The scalability is also investigated.The importance of designing efficient parallel algorithms for evaluating parallel systems is emphasized.     

Parallel algorithms for model reduction of discrete-time systems

Computing reduced-order models of controlled dynamical systems is of fundamental importance in many analysis and synthesis problems in systems and control theory. Algorithmic aspects of model reduction methods based on state-space truncation for linear discrete-time systems are addressed here. In contrast to the often-used approach of applying methods for continuous-time systems to discrete-time models employing a bilinear transformation, we devise special algorithms for discrete-time systems. Usually, this is more reliable and efficient. All methods discussed require in an initial stage the computation of the Gramians of the system. Using an accelerated fixed-point iteration for computing the full-rank factors of the Gramians yields some favorable computational aspects, particularly for non-minimal systems. The computations only require efficient implementations of basic linear algebra operations readily available on modern computer architectures. We discuss aspects of the parallel implementation of these methods and show the performance and scalability on distributed memory computers. Our approach enables users to deal with very complex systems using relatively cheap infrastructure, as, for example, a local PC or workstation network.     

Automating maintenance for a one‐way transmitting blackboard system used for autonomous multi‐tier control

The blackboard architecture has particular utility in applications where conclusions must be drawn in the absence of human involvement. Through properly crafted rules, this approach can determine what a collection of data may mean. This can be utilized by other onboard software to limit transmission to only relevant data or conclusions. Some applications, such as robotic exploration, may preclude or severely limit the availability of controller‐to‐craft‐agent communications. In this case, the maintenance of the system must be performed autonomously.This paper discusses common maintenance tasks that may be relevant to a long‐running blackboard‐based system (e.g. clearing extraneous data from the blackboard regularly to improve performance, archiving relevant but infrequently used data for performance enhancement). A system for automating these tasks is presented that is suitable for most blackboard‐style systems. Its particular utility to those that cannot be easily accessed is discussed. Quantitative analysis of the value of removing rules from the system is performed and presented, and these results are extrapolated to several prospective blackboard maintenance approaches.     

Neural networks,rational functions,and realization theory

The problem of parametrizing single hidden layer scalar neural networks with continuous activation functions is investigated. A connection is drawn between realization theory for linear dynamical systems, rational functions, and neural networks that appears to be new. A result of this connection is a general parametrization of such neural networks in terms of strictly proper rational functions. Some existence and uniqueness results are derived. Jordan decompositions are developed, which show how the general form can be expressed in terms of a sum of canonical second order sections. The parametrization may be useful for studying learning algorithms.This work was supported by the Australian Research Council, the Australian Telecommunications and Electronics Research Board, and the Boeing Commencai Aircraft Company (thanks to John Moore).     

Control of large-scale dynamic systems by aggregation

A method is proposed to obtain a model of a dynamic system with a state vector of high dimension. The model is derived by "aggregating" the original system state vector into a lower-dimensional vector. Some properties of the aggregation method are investigated in the paper. The concept of aggregation, a generalization of that of projection, is related to that of state vector partition and is useful not only in building a model of reduced dimension, but also in unifying several topics in the control theory such as regulators with incomplete state feedback, characteristic value computations, model controls, and bounds on the solution of the matrix Riccati equations, etc. Using the quantitative definition of weak coupling proposed by Milne, a suboptimal control policy for the weakly coupled system is derived. Questions of performance degradation and of stability of such suboptimally controlled systems are also answered in the paper.     

Beyond the cybernetic jam fantasy: the continuator

The Continuator is a usable musical instrument combining techniques from interactive and automatic learning systems. It learns and interactively plays with a user in the user's style. Music-generation systems have traditionally belonged to one of two categories: interactive systems in which players trigger musical phrases, events, or effects, such as the Karma musical workstation, and systems such as Risset's interactive piano, which allow for user input such as keystrokes or chords, but can't learn and use preprogrammed musical styles. Most of these systems propose musical effects libraries (a term used in the Karma workstation meaning a generation of music material based on user input). Although some of these effects are musically impressive, these systems can't be considered cybernetic musicians or even musical companions, because they use preprogrammed reactions and have no memory or facility for evolving.     

A necessary and sufficient condition for feedback stabilization in a factorial ring

The necessity for a coprime fractional representation of a plant, in order to completely parametrize all stabilizing compensators by the Youla theory, is examined. It is shown that the coprimeness is necessary for systems in a factorial ring, a class inclusive of multidimensional scalar systems. Some observations on partial-state transfer functions in the feedback configuration are found to be useful in showing the necessity.     

An expert system for decision support of municipal water pollution control

This study presents an expert system (ES) for assisting departments of environmental management in their efforts to improve water quality in a city. The ES was built based on the premise that municipal water quality is related not only to the environmental conditions of a city, but also to its economic and social systems. The system called WPC-ES can analyze relationships between industrial water pollution and economic activities of industrial enterprises of a city. The system includes a decision model at its core, which integrates another four closely related subsystems. As an application, use of the system by the environmental protection agency of a city in the Yellow River Basin of China is presented. The results showed that the system could provide better decision support for environmental management. Some lessons drawn from development of the system are useful for other development efforts of ES for enhancement of water quality in developing countries.     

Group-specific face verification using soft biometrics

Soft biometrics have been recently proposed for improving the verification performance of biometric recognition systems. Examples of soft biometrics are skin, eyes, hair colour, height, and ethnicity. Some of them are often cheaper than “hard”, standard biometrics (e.g., face and fingerprints) to extract. They exhibit a low discriminant power for recognizing persons, but can add some evidences about the personal identity, and can be useful for a particular set of users. In particular, it is possible to argue that users with a certain high discriminant soft biometric can be better recognized. Identifying such users could be useful in exploiting soft biometrics at the best, as deriving an appropriate methodology for embedding soft-biometric information into the score computed by the main biometric.In this paper, we propose a group-specific algorithm to exploit soft-biometric information in a biometric verification system. Our proposal is exemplified using hair colour and ethnicity as soft biometrics and face as biometric. Hair colour and information about ethnicity can be easily extracted from face images, and used only for a small number of users with highly discriminant hair colour or ethnicity. We show by experiments that for those users, hair colour or ethnicity strongly contributes to reduce the false rejection rate without a significant impact on the false acceptance rate, whilst the performance does not change for other users.     

Parallel program analysis on workstation clusters: Memory utilisation and load balancing

Using a workstation cluster for parallel program development requires consideration of various factors to optimise the mapping of the algorithm to the characteristics of the environment. In this paper we present a new analysis and verification of well-known ideas in parallel programming research of specific importance to both the use and design of workstation cluster computing systems. We define a new performance measure related to memory resource utilisation and show how redundant memory usage can lead to poor memory utilisation of the cluster. We also present analytical and experimental evidence that the pool-of-tasks paradigm can lead to significantly improved speedup over series–parallel algorithms, especially when considering equivalent computational and communication requirements. The effect of load balancing on the series–parallel and pool-of-tasks algorithms is examined, and our analysis and experimental results confirm not only that the pool-of-tasks algorithms are more robust to load imbalances but that the effect of the imbalance is mitigated when more workstations are used. © 1998 John Wiley & Sons, Ltd.     

方块脉冲函数用于线性时变系统的分析和最优控制

本文给出了方块脉冲函数的一些运算性质.利用这些性质求解线性时变系统的状态方程 和基于二次型性能指标的最优控制规律,得出了便于应用的均匀分段恒定解答.较沃尔什函 数逼近法容易导出形式简明的递推算法,且子区间的分段数可选取任意整数,因而节省计算机 内存和机时,有助于提高计算和控制的精度.     

野战分组交换网性能的仿真分析

本文采用计算机仿真的方法研究了野战分组交换网的性能,讨论了影响网络性能的主要因素,通过对仿真结果进行分析,得出了一些有益的结论,为实际野战分组交换网的网络设计提供了理论依据。     

发光器件的计算机图象处理

本文较详细地介绍了光源器件的计算机图象处理系统的构成、原理和程序设计.应用本 方法可准确地测定光源器件发光有效面积.文中计算了注入电流Is和条宽S与光强半宽 W1/2的关系,与实测结果作了比较,证实了测定结果的准确性;设计了一套图象处理程序,可方 便地绘制发光有效面积图、光强分布三维立体图及其等截面图,还可绘制和计算出富有实际意 义的光源器件纵向波导分布图.     

Labeling Line Drawings with Hidden-Part-Drawn of Planar Object with Trihedral Vertices

Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is required to extract three-dimensional information from the two-dimensional line drawings. In this paper, a new labeling theory and method are proposed for the two-dimensional line drawing with hidden-part-draw of a three-dimensional planar object with trihedral vertices. Some rules for labeling line drawing are established. There are 24 kinds of possible junctions for line drawing with hidden-part-draw, in which there are 8 possible Y and 16 W junctions. The three problems are solved that Sugihara's line drawing labeling technique exists. By analyzing the projections of the holes in manifold planar object, we have put forward a labeling method for the line drawing. Our labeling theory and method can discriminate between correct and incorrect hidden-part-draw natural line drawings. The hidden-part-draw natural line drawings can be labeled correctly by our labeling theory and method, whereas the labeling theory of Sugihara can only label the hidden-part-draw unnatural line drawings in which some visible lines must be drawn as hidden lines, and some invisible lines must be drawn as continuous lines.     

Sidle：空闲工作站的调度与远程执行系统

本文介绍我们研制的一个空闲工作站调度与远程执行系统Ｓｉｄｌｅ，该系统当前运行在由以太网连接的１９台ＳＵＮ４工作站上，能对用户的多个作业或一个程序的若干部分进行并行处理。它除了具有目前国外现有系统的优点外，还具有以下特点：支持多个外来任务和嵌套的远程执行，使ＣＰＵ利用率更高，调度对用户有更好的透明性。此外，在性能方面也超过现有的系统。