为测试系统诊断设计并构造规则库和推理机

目前ＶＬＳＩ测试系统日趋复杂，要快速，精确地对它们进行诊断，不得不求助于专家系统，专家知识和解释专家知识并控制诊断进程的机制是专家系统的两大要素，它们又分别被称为规则库和推理机，针对这两大要素，本文阐述以下两方面的问题：（１）设计规则库的结构，（２）设计并构造用于ＶＬＳＩ测试系统诊断的推理机。     

PREPARE: a tool for knowledge base verification

The knowledge base is the most important component in a knowledge-based system. Because a knowledge base is often built in an incremental, piecemeal fashion, potential errors may be inadvertently brought into it. One of the critical issues in developing reliable knowledge-based systems is how to verify the correctness of a knowledge base. The paper describes an automated tool called PREPARE for detecting potential errors in a knowledge base. PREPARE is based on modeling a knowledge base by using a predicate/transition net representation. Inconsistent, redundant, subsumed, circular, and incomplete rules in a knowledge base are then defined as patterns of the predicate/transition net model, and are detected through a syntactic pattern recognition method. The research results to date have indicated that: the methodology ran be adopted in knowledge-based systems where logic is used as knowledge representation formalism; the tool can be invoked at any stage of the system's development, even without a fully functioning inference engine; the predicate/transition net model of knowledge bases is easy to implement and provides a clear and understandable display of the knowledge to be used by the system     

An artificial intelligence system of trouble diagnosis for aircraft engines

:Reported here is about the trouble diagnosis system for AN-24 aircraft engine which has been realized by inputting the experiences of the repair mechanics or experts of the engine as a computer software.The system is composed of following four sections which are called “model” ; a phenomena model, an inference model, a learning model, and an interpretation model.Therefore, the system is called as “model diagnosis system”. These four models are relatively independent which makes parallel operation, easy debugging, and addition of new knowledge possible.

The experience of the engine experts has been stored initially to outer knowledge base in the computer. Intermidiate knowledge which arises on the process of the inference is treated at inner knowledge base. The inner knowledge base adopts a blackboard structure. This makes the system not only able to diagnose the vague preconditioned reason, but also to diagnose the unpreconditioned one by learning. The validity of the system was proved from some experiments.     

VIBEX: an expert system for vibration fault diagnosis of rotating machinery using decision tree and decision table

This paper proposes an expert system called VIBEX (VIBration EXpert) to aid plant operators in diagnosing the cause of abnormal vibration for rotating machinery. In order to automatize the diagnosis, a decision table based on the cause-symptom matrix is used as a probabilistic method for diagnosing abnormal vibration. Also a decision tree is used as the acquisition of structured knowledge in the form of concepts is introduced to build a knowledge base which is indispensable for vibration expert systems. The decision tree is a technique used for building knowledge-based systems by the inductive inference from examples and plays a role itself as a vibration diagnostic tool. The proposed system has been successfully implemented on Microsoft Windows environment and is written in Microsoft Visual Basic and Visual C++. To validate the system performance, the diagnostic system was tested with some examples using the two diagnostic methods.     

Data mining in deductive databases using query flocks

Data mining can be defined as a process for finding trends and patterns in large data. An important technique for extracting useful information, such as regularities, from usually historical data, is called as association rule mining. Most research on data mining is concentrated on traditional relational data model. On the other hand, the query flocks technique, which extends the concept of association rule mining with a ‘generate-and-test’ model for different kind of patterns, can also be applied to deductive databases. In this paper, query flocks technique is extended with view definitions including recursive views. Although in our system query flock technique can be applied to a data base schema including both the intensional data base (IDB) or rules and the extensible data base (EDB) or tabled relations, we have designed an architecture to compile query flocks from datalog into SQL in order to be able to use commercially available data base management systems (DBMS) as an underlying engine of our system. However, since recursive datalog views (IDB's) cannot be converted directly into SQL statements, they are materialized before the final compilation operation. On this architecture, optimizations suitable for the extended query flocks are also introduced. Using the prototype system, which is developed on a commercial database environment, advantages of the new architecture together with the optimizations, are also presented.     

基于专家系统的飞机燃油故障诊断方法研究

对于飞机燃油系统故障诊断问题，提出了一种利用专家系统进行飞机燃油系统故障诊断的新方法。通过构建专家系统知识库和推理机，同时利用LabVIEW工具建立了相应的软件环境，开发了飞机燃油故障诊断系统。仿真结果表明，该系统很好地发挥了专家系统的智能性，能够快速准确地诊断出燃油系统的故障，并能提出有效的重构方案，完全适合于飞机燃油系统的故障诊断。     

A fuzzy-based genetic approach to the diagnosis of manufacturing systems

This paper describes the development of a hybrid approach that integrates graph theory, fuzzy sets and genetic algorithms for the diagnosis of manufacturing systems. The approach enables the modelling of causal relations of system components in manufacturing systems. Based on the model thus established, a worst-first search technique has been proposed and developed for the identification of probable fault-propagation paths. As manufacturing diagnosis often involves the interpretation of uncertainty, fuzzy-set theory is employed for this purpose. Unlike conventional diagnostic systems which assume that all the system components or nodes of a manufacturing system model are measurable, the genetic-algorithm-based search engine developed in this work is able to deal with nodes that cannot be, or are not, measured. Details of the hybrid approach, the worst-first search technique and the genetic-algorithms-based search engine are discussed. The framework of a prototype fuzzy-based genetic diagnostic system is described. Details of the system validation are also presented.     

Content-based image retrieval algorithm acceleration in a low-cost reconfigurable FPGA cluster

The SMILE project main aim is to build an efficient low-cost cluster based on FPGA boards in order to take advantage of its reconfigurable capabilities. This paper shows the cluster architecture, describing: the SMILE nodes, the high-speed communication network for the nodes and the software environment. Simulating complex applications can be very hard, therefore a SystemC model of the whole system has been designed to simplify this task and provide error-free downloading and execution of the applications in the cluster. The hardware–software co-design process involved in the architecture and SystemC design is presented as well. The SMILE cluster functionality is tested executing a real complex Content-Based Information Retrieval (CBIR) parallel application and the performance of the cluster is compared (time, power and cost) with a traditional cluster approach.     

Diagnosis of a class of distributed discrete-event systems

Discrete-event modeling can be applied to a large variety of physical systems, in order to support different tasks, including fault detection, monitoring, and diagnosis. The paper focuses on the model-based diagnosis of a class of distributed discrete-event systems, called active systems. An active system, which is designed to react to possibly harmful external events, is modeled as a network of communicating automata, where each automaton describes the behavior of a system component. Unlike other approaches based on the synchronous composition of automata and on the off-line creation of the model of the entire system, the proposed diagnostic technique deals with asynchronous events and does not need any global diagnoser to be built. Instead, the current approach features a problem-decomposition/solution-composition nature whose core is the online progressive reconstruction of the behavior of the active system, guided by the available observations. This incremental technique makes effective the diagnosis of large-scale active systems, for which the one-shot generation of the global model is almost invariably impossible in practice. The diagnostic method encompasses three steps: (1) reconstruction planning; (2) behavior reconstruction; and (3) diagnosis generation. Step 1 draws a hierarchical decomposition of the behavior reconstruction problem. Reconstruction is made in Step 2, where an intensional representation of all the dynamic behaviors which are consistent with the available system observation is produced. Diagnosis is eventually generated in Step 3, based on the faulty evolutions incorporated within the reconstructed behaviors. The modular approach is formally defined, with special emphasis on Steps 2 and 3, and applied to the power transmission network domain     

面向问题求解的集成软件系统的设计研究

问题求解、信息检索和科学计算、通常是由专家系统、数据库管理系统和科学计算语言系统独立完成的。但许多工程应用的实际问题需要三者有机地结合在一起互相合作。本文结合一个具体的集成软件环境的设计，提出了一个集问题求解，信息检索和科学计算于一体的软件模型，研究了数据库、知识库和科学计算模型库的耦合问题，给出了提高耦合系统运行效率的若干方法。     

基于混合卡尔曼滤波器组的航空发动机双通道传感器故障检测

基于机载非线性模型与分段线性卡尔曼滤波器混合组成的混合卡尔曼滤波器组,结合双通道传感器的特点,建立了民用航空发动机传感器故障诊断系统;给出故障诊断原理及算法的同时,将该系统应用于民用涡扇发动机传感器常见典型故障进行了仿真;仿真结果表明,诊断系统可以在发动机发生健康蜕化后,通过只简单更新机载模型的蜕化因子,而保持线性卡尔曼滤波器的参数不变,便能准确地检测和隔离各类传感器故障而不发生误报;该更新过程可以在线自动完成,省时省力,易于工程实现。     

基于数字化平台的柴油机电控系统可靠性计算

为了评估核电厂应急柴油机数字化控制方案替代部分传统继电器控制系统的可行性,对基于数字化专用仪控平台的柴油机电控系统进行了可靠性分析和计算。依据该系统的架构设计,建立了系统可靠性框图模型,并结合可靠性设计和失效率预计数据,采用蒙特卡罗方法计算得到的系统可用性达到99.99%。分析结果表明,冗余设计、故障诊断和维修性设计对系统可用性影响显著。该研究结论为柴油机电控系统的数字化改造提供了可靠性数据参考,并有助于同类系统在设计阶段有效地提升固有可靠性。多种可靠性分析方法从系统架构、功能安全和运行维护方面更准确地描述了电控系统的可用性,为数字化仪控设备的可靠性分析提供了方法借鉴。     

专家系统中基于粗集的知识获取、更新与推理

知识获取、知识更新和不确定性推理是设计专家系统的重要方面。根据粗集理论，提出了一种专家系统的结构模型，该系统在规则获取的基础上，利用系统运行的实例增量式地更新知识库中的规则及其参数，以改善系统的性能，利用知识库中的规则及数量参数进行不确定性推理，得出结论的可信度。     

海洋环境下武器效能评估系统的知识库构建

为了解决海洋环境下武器装备效能的评估问题,利用成熟的关系数据库技术提出了一种通用的知识表示方法,构建出海洋环境对武器效能影响评估系统的知识库。首先介绍了知识的两类来源,分析了效能评估知识的特点,表明传统的知识表示方法难以满足该评估系统的计算要求。然后详细地阐述了将规则、函数、算法、模型等统一到一个关系数据库中的通用关系知识表示方法,与一般知识表示进行比较,并根据其特点研究通用关系知识库的知识存储结构以及效能评估系统的推理机。最后给出基于框架知识的知识表示和推理实例。一个完善的通用关系知识库的构建将有助于解决海洋环境下武器装备效能的定量评估问题,为决策提供参考。     

Combined simulation for process control: extension of a general purpose simulation tool

Combined discrete event and continuous views of production processes are important in designing computer control systems for both process industries and manufacturing. The paper presents an extension of the popular Matlab–Simulink simulation tool to facilitate the simulation of the discrete sequential control logic applied to continuous processes. The control system is modelled as a combined system where the discrete and the continuous parts of the system are separated and an interface is introduced between them. The sequential control logic is represented by a Sequential Function Chart (SFC). A SFC blockset is defined to enable graphical composition of the SFC and its integration into the Simulink environment. A simulation mechanism is implemented which is called periodically from the standard Simulink simulation engine and carries out the correct state transition sequence of the discrete model and executes corresponding SFC actions. Two simulation case studies are given to illustrate the possible application of the developed simulation environment: the simulation of a batch process cell, as an example from the area of process control and an example of a manufacturing system, i.e. the control of a laboratory scale modular production system.     

Knowledge transformation and fusion in diagnostic systems

Diagnostic systems depend on knowledge bases specifying the causal, structural or functional interactions among components of the diagnosed objects. A diagnostic specification in a diagnostic system is a semantic interpretation of a knowledge base. We introduce the notion of diagnostic specification morphism and some operations of diagnostic specifications that can be used to model knowledge transformation and fusion, respectively. The relation between diagnostic methods in the source system and the target system of a specification morphism is examined. Also, representations of diagnostic methods in a composed system modelled by operations of specifications are given in terms of the corresponding diagnostic methods in its component systems.     

Sensor and actuator fault diagnosis of systems with discrete inputs and outputs

The paper describes a method for detecting and identifying faults that occur in the sensors or in the actuators of dynamical systems with discrete-valued inputs and outputs. The model used in the diagnosis is a stochastic automaton. The generalized observer scheme (GOS), which has been proposed for systems with continuous-variable inputs and outputs some years ago, are developed for discrete systems. This scheme solves the diagnostic problem as an observation problem, which is set up here for discrete-event systems. As the system under consideration is described by a stochastic automaton rather than a differential equation, the mathematical background and the diagnostic algorithms obtained are completely different from the well-known observers developed for continuous-variable systems. The GOS is extended here by a fault detection module to cope with plant faults that are different from actuator or sensor faults. The diagnostic algorithm consists of two steps, the first detecting the existence of a fault and the second isolating possible sensor or actuator faults or identifying plant faults. The results are applied to quantized systems whose discrete inputs and outputs result from a quantization of the continuous-variable input and output signals. Experimental results illustrate the proposed diagnostic method.     

基于语义推理的DSS模型研究与应用

基于语义网理论建立基于语义推理的DSS模型。该模型引用W3C提出的资源描述框架（RDF）以描述业务领域中各要素,形成领域本体。并对领域中业务数据进行语义标注,构建事实库。在所构建事实库的基础上,系统根据预设规则进行推理,以达到决策支持的目的。最后基于以上方法对施工项目设备推荐领域进行实例建模,建立设备推荐系统。该系统将Semantic Web与Ontology理论引入到施工项目领域,以解决施工项目过程中存在的设备选型推荐问题,并作为语义Web理论在该领域内应用的一次尝试。     

网格环境下的航空发动机集成设计与分布仿真研究

建立了一个开发航空发动机分布仿真的系统环境．该环境中子模型具有自治性,子模型的设计者可以根据自己的需要选择所使用的工具,定义变量以及他们与其他设计者之间的关系．应用新兴的网格技术建立了一个集成设计和分布仿真的环境框架,它可以灵活地建立和修改基于部件对象模型建立起来的航空发动机模型,并尝试解决仿真中存在的多学科耦合以及大计算量的问题．该框架具有图形化界面,可以方便地更改发动机的参数和结构,其所具有网格技术的易扩展性也为今后建立更复杂的发动机模型提供了良好的平台．研究人员可以应用该系统提供的可扩展设计和仿真环境,灵活地组建新的航空发动机模型并进行仿真．     

Model theory approach to transaction processing system development

This paper presents a new approach, model theory approach, to small and medium scale transaction processing system (TPS) development. A TPS of this paper is an information system designed to process day-to-day business event data at operational level of an organization. The paper is not concerned with data base construction but with transaction processing.

The model theory approach is not a software engineering approach but a systems theory approach. In the approach a model of the target system, which is called a user model, is constructed in set theory using a formal system structure of a TPS. The user model is, then, compiled into an extended Prolog (extProlog) model. The extProlog is an extension of Prolog to meet requirements for management information system development. On compilation a standardized user interface (UI) called internal UI is attached. The extProlog model with the internal UI is, then, executed under control of another standardized UI called an external UI. Implementation is an integral part of the approach. Because the UIs are designed for the formalized (abstract) structure of a TPS, they can be standardized and are provided as black box components to system development. Because a systems developer is required to only build a user model in set theory based on a model theoretic structure in the approach, it is called a model theory approach. Advantages of this approach are that it provides a theoretical structure to information systems development so that systems development can be made an engineering discipline, and facilitates rapid systems development.