基于对象分布式实时系统的容错模型研究

该文在基于对象的分布式实时系统调度模型研究的基础上,对G-Net模型进行了扩展,即给出了一种基于时间约束G-Net的分布式实时系统容错模型。该模型提供了容错和模块化机制,降低了分布式实时系统设计的复杂性,提高了系统的可维护性,有助于大型复杂可靠的分布式实时系统的设计。最后,该文还给出了基于时间约束G-Net模拟器的结构。     

利用UML建立学生就业管理系统模型

UML是可视化建模的工业标准[2]。本文论述了建立良好的模型对开发大型系统的重要性。并以学生就业管理系统为例,来重点说明运用UML来建立系统应用模型的过程。     

系统辨识在水压仿真器试验建模中的应用

水压仿真器作为一种特殊电液压力伺服系统,通过控制伺服阀的开口直接控制工作腔的压力变化,很难通过理论方法进行建模。应用系统辨识方法对水压仿真器的数学模型进行了研究,首先设计能使系统稳定的简单闭环,再对系统施加合适的输入信号,记录系统的输出信号进行试验建模,最后推导出被控对象的数学模型。经过验证,辨识模型基本能够反映实际系统的特性,这种辨识方法是研究水压仿真器或相似压力伺服系统特性的一种可行方法。     

利用UML建立学生就业管理系统模型

UML是可视化建模的工业标准。本文论述了建立良好的模型对开发大型系统的重要性。并以学生就业管理系统为倒，来重点说明运用UML来建立系统应用模型的过程。     

基于系统辨识算法的风力机桨距系统故障诊断

针对风力机桨距系统故障,提出一种基于观测器的多新息随机梯度辨识算法的故障诊断方法．多新息随机梯度辨识算法通过扩展新息长度能够改进随机梯度辨识算法的估计精度,根据系统的规范状态空间模型,结合状态观测器可以实现系统状态和参数的交互估计．将桨距系统模型转换为可辨识的状态空间模型,依据桨距系统故障会引起系统参数变化的特点,采用所提出的算法对系统状态和参数进行估计,将桨距系统故障诊断问题转化为系统状态和参数估计问题．仿真结果表明,所提出的方法能够有效诊断桨距系统故障．     

An investigation on the nature of decision support system software

Decision Support Systems (DSS) software is investigated and a conceptual model presented in this paper. The purpose of this model is to facilitate a better understanding of the nature of DSS software. The model is composed of six problem transformational processes linking up seven problem phases. The six transformational processes are: problem transforming system, problem mapping system, problem solving system, procedural program generation system, programming language compiling system, and code generation system, by identifying the seven problem phases this hierarchical provides a conceptual foundation for developing DSS software. Spun-off from this model is a framework for implementing knowledge-based DSS with automatic modeling capabilities. The structure of future DSS software to run on fifth generation computers is also addressed.     

模糊系统理论在宏观调控研究中的应用

本文为解决宏观调控系统中各种量不确定问题，建立一种较实用的模糊系统模式，用以描述该系统。文中就此模式的连续性，稳定性等进行讨论，并将这种模糊系统模式应用地宏观经济调控研究中。     

On the stability of qualitative models

This paper considers a discrete-time continuous-variable autonomous system for which only a quantised state measurement [x(k)] is available. The qualitative model of this system is a nondeterministic automaton thay describes, for a given quantised initial state [x(0)], the sequence of quantised states [x(k)]. The paper deals with the question for which stable linear systems is the qualitative model also stable. A necessary and sufficient condition on the qualitative model is proved under which the continuous-variable system is stable. This condition refers to the eventual boundedness of the nondeterministic automation. An example demonstrates that this stability criterion can be used only if a qualitative model of the system is available.     

柔性工作流建模引入NVP 的可靠性优化研究

针对当前大型企业的工作流管理系统普遍存在建模能力不充分、可靠性不足等问题,提出一种基于N版本程序设计（N-Version Programming）容错策略的柔性工作流建模方法,该方法相比于传统工作流模型,有效应用N版本程序设计容错模式,为工作流关键活动节点增加容错机制,从而显著提升工作流管理系统的可靠性．同时为满足模型应用的现实需求,详细分析N版本程序设计的可靠性优化,最后通过模型实例,说明该建模方法在模型描述能力和系统可靠性方面的优势．     

并行计算机高可用性分析与设计

随着并行计算机系统规模的不断增大,系统的失效率呈线性增长。如何保证大规模并行系统能够提供持续不断的服务,即提高系统的可用性,达到高可用的目标,已成为并行系统设计的重要方面。系统级容错的概念目前已经提出,但系统可用性的度量仍然需要深入研究。本文运用组合模型和马尔科夫过程模型,对系统可靠性和可用性进行了建模模和分析,推导了基于马尔科夫过程的可用性度量公式,得出运用高可用技术可以提高系统的可用性。在此基础上,还给出了一个大规模并行计算机系统的高可用系统结构。     

Petri网化简规则在系统中的实现

Petri网是分析系统的一种很好的数学和图形工具。网的复杂性随着网中可达状态和变迁数目的增加而大大增加。这就使得对一个复杂网分析的难度不易控制。对此,提出了化简的思想,降低复杂度后再分析。文章将化简规则转化成算法,并在实际系统中实现。     

Fuzzy bounded least-squares method for the identification of linearsystems

This paper presents the fuzzy bounded least-squares method which uses both linguistic information and numerical data to identify linear systems. This method introduces a new type of fuzzy system, i.e., a fuzzy interval system. The steps in the method are as follows: 1) to utilize all the available linguistic information to obtain a fuzzy interval system and then to use the fuzzy interval system to give the admissible model set (i.e., the set of all models which are acceptable and reasonable from the point of view of linguistic information); 2) to find a model in the admissible model set which best fits the available numerical data. It is shown that such a model can be obtained by a quadratic programming approach. By comparing this method with the least-squares method, it is proved that the model obtained by this method fits a real system better than the model obtained by the least-squares method. In addition, this method also checks the adequacy of linear models for modeling a given system during the identification process and can help one to decide whether it is necessary to use nonlinear models     

On the use of OBDDs in model-based diagnosis: An approach based on the partition of the model

In this paper, we discuss how Ordered Binary Decision Diagrams (OBDDs) can be exploited for the computation of consistency-based diagnoses in model-based diagnosis. Since it is not always possible to efficiently encode the whole system model within a single OBDD, we propose to build a set of OBDDs, each one encoding a portion of the original model. For each portion of the model, we compute an OBDD encoding the set of local diagnoses; the OBDD encoding global diagnoses is then obtained by merging all the local-diagnoses OBDDs. Finally, minimal-cardinality diagnoses can be efficiently computed and extracted.The paper reports formal results about soundness, completeness and computational complexity of the proposed algorithm. Thanks to the fact that encoding diagnoses is in general much simpler than encoding the whole system model, this approach allows for the successful computation of global diagnoses even if the system model could not be compiled into a single OBDD. This is exemplified referring to a challenging combinatorial digital circuit taken from the ISCAS85 benchmark.     

“软件人”感知系统的协同分类模型研究

“软件人”是计算机网络世界中的一类软件人工生命，是一种网络中的“虚拟机器人”，它具有拟人结构。作为对人的模拟，其感知系统应该像人的感知系统一样，具有区分感知对象的能力。基于人体感知系统的启发，运用大系统分析的“分解一集结”方法，本文提出了一种“软件人”感知系统的协同分类模型。该模型通过多分类器系统模拟人的不同感觉，从而实现“软件人”对感知对象的多感觉协同分类。仿真实验结果初步验证了本文提出模型的可行性。今后的工作是研究如何构造实际系统并将其应用于数字气田建设的数据处理工作中。     

水面舰艇CGF系统的若干关键技术研究

水面舰艇计算机生成兵力，是海战模拟中的重要环节，是模拟海战场的重要组成部分。通过建立水面舰艇的运动、动力学数学模型，同时建立舰艇上有关情报侦察系统、武器系统的数学模型，实现这些模型的仿真运行，建立水面舰艇CGF，并将该CGF置于战术模拟训练仿真环境中，对于提高战场环境的仿真可信度，提高模拟训练的效果具有重要意义。该文对水面舰艇CGF系统的工作原理、物理模型、智能决策模型等关键技术进行了研究，并给出了水面舰艇CGF系统简化的舰艇机动模型、舰空导弹弹道模型、对空警戒雷达的功能仿真模型。对完善水面舰艇CGF系统，进一步研究海军训练DIS系统有很重要的意义。     

Optimization of the structure of multifunctional information systems according to the criterion of a required value of the efficiency ratio

A model of the reliability of multifunctional information systems is proposed. Based on this model an integral estimation of the reliability of such systems is obtained, expressed in the form of an efficiency ratio. An algorithm for optimization of a multifunctional information system according to the criterion of a required value of the efficiency ratio of the system is presented. The algorithm is illustrated by an example.     

Numerical Linearisation Method to Efficiently Optimise the Oscillation Damping of an Interdisciplinary System Model

This paper presents a method to numerically linearise a complex mechanicalsystem. The method is applied to the parameter optimisation of a controlled elastic hydro-mechanical system. The virtual spring damper control concept is used to damp the oscillating system. The system dynamics of the full system are modelled as an interdisciplinary model. From this a mechanical substitution model is derived and linearised at a given operating point. The system matrix of the linearised system is used to efficiently calculate an optimisation criterion that leads to optimal control parameters for rapid oscillation damping. To verify the results a classical, but very time consuming, optimisation is performed. The quality of the optimal parameter sets found is evaluated by comparing simulation results of the complex interdisciplinary model. The system response is almost the same in both cases. The parameters found using the linear model are only slightly different to the parameters found using the non-linear and interdisciplinary model. The performance of the linear model based optimisation is good – it reduces the computational cost by a factor of more than one hundred.     

Fault detection and isolation of the three-tank system using the modal interval analysis

Analytical redundancy is a widely used technique for fault detection. It consists of comparing the behaviour of a real system with a reference obtained by simulation of its model. The main problem is that there are always imprecisions and uncertainties which are not represented in the model so the behaviour of the real system and the behaviour of the model are not exactly the same. One way to represent these uncertainties in the model is using interval models. The results of the simulation of these types of models may be represented by envelopes. This paper proposes an approach to generate envelopes based on interval techniques of the modal interval analysis. As an example, this approach is used to detect and isolate faults in a physical system formed by three interconnected tanks.     

Conditions of exact tracking by the linear system output of the standard model of a reduced order

A problem is considered for an exact tracking by the output of a linear stationary system presented in the space of states of the standard model of a reduced order in comparison with the dimension of the system state vector. A minimum possible order of the standard model is defined, at which it is possible to perform the exact tracking of it by the output, conditions are defined of the exact tracking by the output of the standard model of a reduced order, and also a set of the control laws that ensure the exact tracking and the internal stability of the system. The solution relies on the method of canonization of matrices. A methodical example is given.     

On the role of a queueing network model in the design of a complex assembly system

This paper describes the modeling, analysis and re-design of a complex assembly system consisting of many processes (assembly, testing and inspection) and resources (machines and operators) and an advanced material handling system with intricate routing logics. It presents a systematic approach using both analytical and simulation models for the evaluation and modification of the complex assembly system. It demonstrates the application of a queueing network model to quickly generate rough-cut solutions and provide qualitative information for the evaluation of design alternatives. Iteratively, processes and resources that affect the system performance are identified, one at a time, and the system modified accordingly, until a satisfactory performance is obtained. The preliminary analyses using the queueing network model help to identify bottleneck processes, estimate optimal pallets, and determine a more efficient system layout. The use of the analytical model significantly reduces the number of the lengthy simulation runs. A detailed simulation model is subsequently employed for fine-tuning and further improvement. Compared with the original design, significant improvements have been made: a higher throughput, a reduced cycle time with less operators, and lower WIP inventories.