基于产生式规则的“机械零部件失效分析,失效诊断专家系统”的研究

本文介绍了基于产生式规则专家系统的基本结构和工作原理。在机械零部件失效分析、失效诊断中表明该系统具有良好的知识获取能力，实时分析，诊断能力。为了提高该系统的性能，提出了联合使用神经网络和专家系统技术的设想。     

一个基于神经网络的专家系统

医疗专家系统主要使用基于知识的技术，其中的决策规则和策略来自于人类的专家。把这些知识和各种推理方法结合，可以建立一个模拟专家决策过程的系统。建立这样一个系统，需要经常与专家磋商，以获取专家的知识，因而需要大量的时间和精力。为此，本文提出直接从数据中提取有效的信息，即用神经网络提取隐含在大量数据中对医疗诊断有效的信息，继之与基于规则的知识，各种推理方法相结合，建立一个神经网络专家系统。     

基于神经网络和框架推理的风险应对专家系统

为了提高飞机装配项目风险应对的效率及可靠性,提出一种将神经网络和框架知识系统相结合的风险应对方法。该方法基于框架表示理论,以方案与风险因子之间存在映射为规则,将专家风险应对经验存储于专家系统知识库之中。使训练后的神经网络以连接权的形式获取知识。使用时,运用匹配算法对神经网络输出和知识库中的知识进行推理匹配,得到最终应对方案。该方法在某型飞机装配项目的风险管理中得到应用,验证了方法的有效性。     

病虫害诊断的神经网络专家系统的设计与实现

本文设计了病虫害诊断的神经网络专家系统的知识获取，知识库、推理机制和人机界面等主要功能模块，并实现了基于改进型神经网络的棉花病虫害诊断专家系统。该诊断系统已投入了实际使用，收到了明显的经济效益。     

基于专家系统的减速离合器故障诊断研究

介绍专家系统的原理.并把专家系统方法应用在减速离合器故障信号诊断中,实现了基于专家系统的产品故障诊断功能.应用故障树分析法建立专家系统的知识库部分,通过故障树定性分析,再将简化的故障树用于基于规则的专家系统的知识库,既能解决知识获取的困难,又能简化知识库,降低知识的冗余,有利于系统的快速诊断.     

煤矿瓦斯预测知识获取模型的应用研究

将粗糙集与神经网络结合,提出由样本更新、粗糙集预处理、神经网络训练、规则提取4个模块组成的煤矿瓦斯预测知识获取模型,将其应用于实时数据进行实验,结果表明,该模型实时性好、可靠性及精度高,可以较好地解决煤矿瓦斯预测知识获取困难的问题,为煤矿瓦斯预测专家系统知识库的建立奠定基础。     

基于改进的BP网络的语法分析系统设计

针对汉语语法分析问题提出了一种基于改进的BP网络的语法分析专家系统的设计方案。其核心是构造存储和管理文法知识的知识库及具有语言专家智能行为和语法分析能力的推理机。本系统中知识库采用产生式规则的知识表达方式，并将知识二元化存储在神经网络中；推理机采用神经网络进行推理。最后给出了系统的运行实例，说明该系统的有效性。     

基于人工神经网络的葡萄病害诊断专家系统

设计了一种基于人工神经网络的葡萄病害诊断专家系统。以常见的18种主要的葡萄病害为研究对象,将专家知识转换为诊断规则,并作为学习样本输入神经网络进行训练,形成人工神经网络推理机。同时,采用知识库、规则推理和人工神经网络推理相结合的系统结构来优化专家系统,在提高专家系统自学能力的同时也提高了系统的响应速度。采用C#、Matlab和.NET技术混合编程实现专家系统,实验结果表明该系统有较高的诊断准确率并能稳定运行。该系统在Web上运行,更有利于系统的推广应用。     

初中几何专家系统中的知识获取及实现

描述了初中几何专家系统中知识获取及实现的一般过程,指出了知识获取及实现中的难点和重点。由于研究问题的复杂性,专家系统规则库中规则量往往十分庞大,这给规则库的管理和维护带来很大不便。专家系统知识库的冗余性是影响系统运行效率和知识库维护的一个重要方面,针对一个具体的专家系统——平面几何智能解题系统,分析了关于知识库规则生成时效率低的问题,然后利用基于粗糙集的约简理论来消除和减少规则库的冗余,使得系统规则库中的规则精炼、简洁,易于维护,同时大大提高了系统的效率。     

汽轮发电机组故障诊断专家系统的研究

建立一个基于知识的汽轮发电机组故障诊断专家系统ＫＢＦＤＥＳ，该系统采用“框架＋规则”知识表示技术，并将框架驻留在内存，而将规则驻留在虚拟盘上；在诊断过程中采用广义的不精确推理策略，并对重要信息用一个组合神经网络进行智能识别；系统将神经网络技术和ＩＤ３算法结合，可以实现从诊断实例自动获取知识。     

FMS智能故障诊断专家系统的建立和开发

采用基于人工智能的故障诊断专家系统方法，附以模糊数学、神经网络、机器学习、数据库等理论，解决故障诊断中知识的合理表达，基于符号和数值的多种快速推理机制，知识的自动获取及知识库智能化管理等关键技术，建立了一个智能模糊故障诊断专家系统。     

基于模糊自组织映射神经网络的故障诊断方法

在研究Kohonen自组织映射网络理论的基础上运用模糊理论方法建立了刹车系统模糊故障诊断模型。该模型只需选择足够的具有代表性的故障样本训练神经网络，将代表故障的信息输入给训练好的神经网络，根据神经网络的输出结果，就可以判断发生故障的类型。该模型除能识别已训练过的故障，还能识别未训练过的故障，并且聚类能力强、速度快，因此很符合复杂系统的故障诊断。     

医学专家系统中知识表示、获取和推理的两种方法

文章提出使用模糊数学的方法和基于规则的神经网络的方法来构造一个呼吸道疾病方面的专家系统,包括知识的表示、获取和推理。对模糊数学方法,用模糊集来表示所考虑的症状与所有可能的疾病。医学知识存储在症状与疾病的模糊关系上。推理时使用模糊关系合成的方法。对基于规则的神经网络方法,从规则集中自动构造网络的结构,确定隐层节点数和连接权值。用并行的方法进行推理。     

A Multi-Net System for the Fault Diagnosis of a Diesel Engine

A multi-net fault diagnosis system designed to provide an early warning of combustion-related faults in a diesel engine is presented. Two faults (a leaking exhaust valve and a leaking fuel injector nozzle) were physically induced (at separate times) in the engine. A pressure transducer was used to sense the in-cylinder pressure changes during engine cycles under both of these conditions, and during normal operation. Data corresponding to these measurements were used to train artificial neural nets to recognise the faults, and to discriminate between them and normal operation. Individually trained nets, some of which were trained on subtasks, were combined to form a multi-net system. The multi-net system is shown to be effective when compared with the performance of the component nets from which it was assembled. The system is also shown to outperform a decision-tree algorithm (C5.0), and a human expert; comparisons which show the complexity of the required discrimination. The results illustrate the improvements in performance that can come about from the effective use of both problem decomposition and redundancy in the construction of multi-net systems.     

A Neural Network Approach for the Determination of Interhospital Transport Mode

We report on the construction of neural networks for determining whether pediatric patients requiring transport to a tertiary care center should be moved by air or by ground. The networks were based on the functional-link net architecture. In two experiments, feedfonvard supervised-learning neural nets were trained with examples of an expert's decisions and then were used in a consulting mode to provide advice on cases not previously encountered. Training and validation were performed by a combination of the k-fold cross-validation and leaving-one-out sampling methods. Use of the functional-link net rather than the customary backpropagation net enabled us to carry out the training with fairly large amounts of data in realistically short time periods. In the first experiment, capillary refill, skin color, and stridor were consistently the input variables that were most strongly associated with the decision output. In both experiments, the networks were validated by comparing their performance retrospectively against the determination of an expert pediatric transport physician. The network was trained based on the expert's opinion about the correct mode of transport for each case with error rates of less than 10^-5.     

基于BP神经网络的水牛疾病诊断系统

针对传统专家系统获取知识困难自学习能力差和推理能力弱等缺点,设计并实现了基于BP神经网络的水牛疾病诊断专家系统.系统用专家以往诊断水牛疾病的病历来训练神经网络,并通过训练过的神经网络来实现疾病的诊断,然后针对诊断结果进行反向推理以确诊水牛疾病,结果表明,该系统很好地改进了传统专家系统存在的一些缺点.另外,该水牛疾病诊断系统的实现方法可推广应用到其它动物的疾病诊断系统中,为疾病诊断系统的开发提供了一条有效的新途径.     

Evaluation of the Use of Induction in the Development of a Medical Expert System

In an earlier study, two medical expert systems for diagnosing thyroid disorders, developed by the application of induction on a sample of previously diagnosed cases and on expert-generated rules, diagnosed a set of test cases better than an expert system developed by the more traditional method of collaboration between a knowledge engineer and an expert. In this paper, an alternative measure of the accuracy of diagnosis of each system is used to evaluate the systems. Diagnoses for every distinct case represented by a combination of indicating factors are compared with diagnoses that the expert made. The induced systems provide diagnoses for many more distinct cases, but a much higher proportion of these diagnoses are incorrect. It is argued that generalizing to unseen cases is an inappropriate use of induction algorithms. The systematic development of a decision table is a more appropriate method for devising a medical expert system.     

用于一致性检查的知识库Petri网模型

知识库是一致性是决定专家系统效率及求解正确性的关键因素。本文以Ｐｅｔｒｉ网为工具对知识库进行模拟分析，把知识库一致性的检查化简为线性代数问题，把这一方法应用于分布式知识库系统，首次得到了检查其一致性的形式方法。本文最后给出了一致性检查的充分必要条件，为建立（分布式）知识库的自动维护系统打下了基础。     

A Recency Inference Engine for Connectionist Knowledge Bases

Knowledge-based neural networks (KBNNs) can be used as expert system knowledge bases. This approach shifts the interests in using connectionist knowledge bases for inferencing in an interactive fashion and giving reasonable justifications for their conclusions. The primary goal of this article is to present a good inference and control mechanism for such knowledge bases. For this purpose, the article develops a stand alone inference engine that uses a connectionist knowledge base, seeks to reduce the amount of data requested in order to reach a conclusion, and explains how a particular conclusion was reached. The inference engine was evaluated on illustrative example applications. Results obtained demonstrate that in spite of its simplicity the presented technique is superior to other techniques over sparse input knowledge bases.     

Stock market one-day ahead movement prediction using disparate data sources

There are several commercial financial expert systems that can be used for trading on the stock exchange. However, their predictions are somewhat limited since they primarily rely on time-series analysis of the market. With the rise of the Internet, new forms of collective intelligence (e.g. Google and Wikipedia) have emerged, representing a new generation of “crowd-sourced” knowledge bases. They collate information on publicly traded companies, while capturing web traffic statistics that reflect the public’s collective interest. Google and Wikipedia have become important “knowledge bases” for investors. In this research, we hypothesize that combining disparate online data sources with traditional time-series and technical indicators for a stock can provide a more effective and intelligent daily trading expert system. Three machine learning models, decision trees, neural networks and support vector machines, serve as the basis for our “inference engine”. To evaluate the performance of our expert system, we present a case study based on the AAPL (Apple NASDAQ) stock. Our expert system had an 85% accuracy in predicting the next-day AAPL stock movement, which outperforms the reported rates in the literature. Our results suggest that: (a) the knowledge base of financial expert systems can benefit from data captured from nontraditional “experts” like Google and Wikipedia; (b) diversifying the knowledge base by combining data from disparate sources can help improve the performance of financial expert systems; and (c) the use of simple machine learning models for inference and rule generation is appropriate with our rich knowledge database. Finally, an intelligent decision making tool is provided to assist investors in making trading decisions on any stock, commodity or index.