A review of conventional and knowledge based systems for machining price quotation

Price estimation for the preparation of quotations is critical process for companies that have to struggle to get orders by offering competitive pricing. For machining companies, said process is complex because of the large amount of variation that can occur. In this case, a manufacturing expert is generally in charge of this task. However, manufacturing experts have several other important tasks to which they must attend. The use of software systems that automate the estimation of costs and prices is common, knowledge-based systems are one of the primary alternatives for two fundamental reasons: they behave the same way an expert would and they save and maintain all knowledge within the company regardless of who has worked on them. This paper covers the principal cost and price estimation methods and reviews the knowledge-based systems that have been implemented in the area of machined part manufacturing. Recommendations as to how future knowledge-based systems for the estimation of this type of pricing should develop are also included.     

A data analysis decision support system for the carbon dioxide capture process

This paper presents the development process of an expert decision support system for pre-filtering and analysis of data from the carbon dioxide (CO₂) capture process. Chemical absorption has become one of the dominant CO₂ capture technologies because of its efficiency and low cost. Since the chemical absorption process consists of dozens of components, it generates more than a 100 different types of data. Monitoring the vast amount of data can be complex, and data filtering and analysis processes are desirable. Specifically, invalid data captured as the equipment is started and shut down need to be filtered, and the filtered data need to be analyzed for different purposes. The expert decision support system for data pre-filtering and analysis not only filters out invalid data using different expert rules, but it can also modify or reuse filtering settings, and export the filtered data to various file formats for further analysis. During development of the expert decision support system, knowledge acquisition was emphasized. The system development process incorporated various technologies including the model-view-control (MVC) design pattern, the embedded database technology, the Java event delivery techniques and the eXtensible Markup Language (XML). Some sample sessions from system executions and some results generated from pre-filtering the data will also be discussed.     

基于优化神经网络算法的大数据专家系统的继电保护二次回路故障定位系统(RSFLS)的研究与实现

为解决继电保护二次回路故障排查耗时耗力、考虑因素不全面、受限于人员经验等问题,本文提出基于优化神经网络的大数据专家系统的方法,并搭建继电保护二次回路故障定位系统（RSFLS）。在对继电保护二次回路抽象分类的基础上,建立基于实体-关系模型（E-R模型）的缺陷数据库模型,利用优化神经网络进行随机化和自学习,并融合继电保护人员的经验库,形成基于优化神经网络的专家系统架构,从而匹配定位故障点。该方法有效解决了传统二次回路故障排查方法所存在的准确性不高、随机性较大、时效性较低等问题。基于该方法开发的RSFLS系统已投入实际应用,能有效缩短继电保护二次回路故障排查时间、提高排查准确性。测试结果证明所述方法和系统在提升继电保护系统可靠性方面有显著效果。     

Using a fuzzy approach to support financial analysis in the corporate acquisition process

In the global market place, many companies have had to adapt their strategies to meet significant challenges. A strategy adopted by some companies has been international expansion via acquisitions. The need for expert knowledge to determine an appropriate company to acquire has been complicated by the sheer size of the global market place. The costs associated with this in relation to time and personnel have created the need for a computerised expert system to be developed. This paper endeavours to show how a proposed fuzzy based system can assist in the identification of a company for acquisition. The authors discuss the manipulation of the magnitude of fuzzy membership functions to communicate priorities within the system. The fuzzy system is designed to assist financial experts in identifying a suitable company for acquisition in the corporate acquisition process. This includes the deliberate weighting of certain inputs and results above others in the decision-making process. The system attempts to learn and simulate the human precedence given to particular financial statistics in company analysis. The system uses the magnitude of the fuzzy membership functions to reflect the human precedence given to each financial ratio. This enables a particular company's strengths and weakness to be considered while concurrently considering their significance and relevance to the acquiring organisation. The system will enable a larger number of companies to be analysed in a more time and cost-effective manner. The development of this system is intended to illustrate that a fuzzy system can aid the financial experts of an acquiring organisation in the global acquisition process.     

Expert system-based selection of the preferred direction of build for rapid prototyping processes

Current commercial rapid prototyping technologies are based on a layered additive process to build parts. The layer-based process results in a stairstepping effect, which can be apparent on curved and sloped surfaces. The selection of the build orientation, whether based on experience, trial and error, or not even considered, is one critical factor that affects the quality of the surface finish. Furthermore, it influences other important aspects, such as the build time and the amount of support structure needed. The authors propose an expert system tool that considers the various parameters that affect the production of the prototype and interacts with the user to recommend the best direction to build. The recommendation is based both on the user's input and on a decision matrix based on the result of interviews with experts, which is implemented within the expert system. If an optimal orientation is not possible, the tool helps the user to select an acceptable build direction. The expert system can also draw attention to issues such as trapped volumes, which can be detrimental to the build process. It helps to reduce the design time, to automate the build process and to minimize the cost of the prototype. The results of this work form a base for ongoing research to complete a tool that considers all major issues for a preferred orientation.     

Knowledge-based approach and system for assembly-oriented design,Part II: the system implementation

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the second part of the report (Part II). It will focus on the development of knowledge-based expert design system for assembly oriented design. The knowledge-based assembly oriented design system, i.e., the assembly oriented design expert system (AODES) is constructed to integrate assembly modeling and design, assembly planning, assemblability analysis and evaluation within a concurrent engineering environment. This intelligent system is implemented by integrating object-oriented representation, constraint-based modeling, rule-based reasoning, truth maintenance, and interfacing to database management system and CAD module, in which fuzzy logic based knowledge representation and inference technique are also applied to deal with uncertain data and knowledge in the design process. The developed system differs from the existing systems adopting part-first bottom-up modeling technique, in which a comprehensive intelligent framework is used for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. It is able to help obtain better design ideas, provide users with suggestions so as to create and improve a design, and therefore give users the possibility to assess and reduce the total production cost at an early stage during the design process. Through the use of the system, the concurrent engineering knowledge can be effectively incorporated into the assembly design process in an integrated manner. A case assembly design shows that the intelligent modeling and design system is feasible.     

Expert System Hardware for Fault Detection

This paper focuses upon the development of three new electronic architectures of inference engines as a part of a hardware expert system applied to very high-speed faults detection in industrial processes. The architecture of this expert system consists of an inference engine (a dedicated processor that is necessary due to the high-speed requirements and the repetitiveness of the operation), which uses a pattern-directed inference system; a fact base, which stores the status of the signals at each moment, and a static knowledge base, which contains the inference rules compiled from expert knowledge. A circuit for analyzing time is also presented. This allows time to be taken as another variable of the process and carries out a redundancy analysis simultaneously with the fault detection module.     

Using enterprise architecture analysis and interview data to estimate service response time

Insights into service response time is important for service-oriented architectures and service management. However, directly measuring the service response time is not always feasible or can be very costly. This paper extends an analytical modeling method which uses enterprise architecture modeling to support the analysis. The extensions consist of (i) a formalization using the Hybrid Probabilistic Relational Model formalism, (ii) an implementation in an analysis tool for enterprise architecture and (iii) a data collection approach using expert assessments collected via interviews and questionnaires. The accuracy and cost effectiveness of the method was tested empirically by comparing it with direct performance measurements of five services of a geographical information system at a Swedish utility company. The tests indicate that the proposed method can be a viable option for rapid service response time estimates when a moderate accuracy within 15% is sufficient.     

X射线粉末衍射仪智能辅助校正系统

X射线粉末衍射仪（X-Ray powder Diffraction,XRD）是物质研究的精密仪器,物理结构复杂,微小的硬件偏差会对衍射数据质量造成影响,对其硬件设备进行偏差校正将有效保证数据正确性,在校正偏差前需要进行偏差类型识别.通常衍射仪设备调校多由设备厂商专家使用专用仪器和设备逐项排查的方式进行偏差校正,对人员经验有较高依赖、调校过程复杂且效率低.为了提高偏差识别效率,本文探讨了X射线粉末衍射仪偏差类型及其产生原因,并开发了一套基于分类预测的X射线粉末衍射仪智能辅助校正系统.该系统采用通用计算机硬件平台,通过特征提取、模型训练等步骤分析标准样品衍射数据,自动化识别仪器状态、辅助校正.结果表明该系统可以快速识别偏差,达到辅助校正的目的.     

Decision support in the quotation process of engineered-to-order products

Sub-suppliers acting in the supply chain of the car industry have to adopt a strategy of products customization to be at the competitive edge. This is caused by the diversity of client’s requirements that entails customer engineered products with a high level of variety. A business strategy based on engineered-to-order products requires systems for efficient generation of product variants. This also includes a need of decision support in the order preparation process as well as in the quotation preparation process. Decision support that gives access to detailed and accurate information in the quotation preparation enables a high level of product adaptation while ensuring company efficiency. By the introduction of a design automation system, this can be achieved. However, means to manage different application domains, projects, task knowledge and design information are required together with a possibility to perform detailed analyses on the system generated information. The objective of this work is to contribute in that area. Initially, a number of success criteria were identified and explorative work was conducted for the purpose to develop a conceptual model and principles that an application system would reside upon. The result is a framework consisting of an information model and underlying principles to be used when developing a design automation system for quotation preparation. A system founded on the framework supports management and analysis of quotations and product variants. The functionality and usefulness has been demonstrated and validated by a system implementation developed in collaboration with an industry partner.     

基于Internet的远程故障诊断系统的研究

提出了一种基于Internet的远程故障诊断系统IRDS（Internet-based Remote Fault Diagnosis System）,该系统既可用于现场诊断,也可以实现远程诊断,将机器的知识库和专家知识经验充分结合起来。在本文中,重点介绍了网络组成和Web数据库技术,真正做到了资源共享,提高了效率,降低了成本,适应现代生产发展的需要。     

航电设备故障诊断专家系统研究与实现

对航电设备和故障诊断专家系统研究的基础上,设计了“智能指引完备过程规则树”的知识表示方式和存储结构,实现了完整表达和记录专家排故经验的功能,给出了一种与规则树对应的诊断方法,通过计算机操作即可自动、真实地模拟专家的思想进行排故,该系统已成功应用于国家某重点项目中,实践表明该系统能提高故障诊断的定位准确度和定位速度,设计思想具有通用性,可应用于其他领域的故障诊断专家系统。     

Dynamic evaluation of the development process of knowledge-based information systems

Codifying expert domain knowledge is a difficult and expensive task. To evaluate the quality of the outcome, often the same domain expert or a colleague of similar expertise is relied on to undertake a direct evaluation of the knowledge-based system or indirectly by preparing appropriate test data. During an incremental knowledge acquisition process, a data stream is available, and the knowledge base is observed and amended by an expert each time it produces an error. Using the kept record of the system’s performance, we propose an evaluation process to estimate its effectiveness as it gets evolved. We instantiate this process for an incremental knowledge acquisition methodology, Ripple Down Rules. We estimate the added value in each knowledge base update. Using these values, the decision makers in the organisation employing the knowledge-based information system can apply a cost-benefit analysis of the continuation of the incremental knowledge acquisition process. They can then determine when this process, involving keeping an expert online, should be terminated. As a result, the expert is not kept on-line longer than it is absolutely necessary. Hence, a major expense in deploying the information system—the cost of keeping a domain expert on-line—is reduced.     

Nontechnical problems in knowledge engineering: Implications for project management

Building knowledge-based systems is generally seen as a technical process. While technical difficulties do arise in the course of this process, nontechnical aspects of project development can also be problematic. However, the latter may be harder for technically trained project personnel to recognize as such and solve. This paper addresses some nontechnical issues that can arise in the course of expert systems projects. Some are already well known in the expert systems world; others may not normally be thought of as issues at all, but we urge that they be considered as such. Since all such issues waste time, money, and goodwill, project personnel have reason to identify and avoid them.     

Automatic reintegration of previously machined materials

Processed material can become obsolete for several “business” reasons. Virtually all manufacturing operations accumulate processed materials that can not be used anymore. Current systems to integrate previously machined materials back into the manufacturing process are informal and often not economically feasible. To utilize material more effectively, the raw material selection process should include obsolete parts as well as raw stock in their scope of selection. A prototype expert system has been developed in Prolog to manage the material salvage operations. The expert system will determine whether an obsolete part can be used to make an alternative part based on a search through the part design database. The expert system is written in Prolog and uses first- order predicate logic to determine whether one part will fit inside another part. The current prototype handles rotational parts.     

A quantitative model for the support of software management

The software production and maintenance management support project (SPMMS) will define and produce a complete, consistent and efficient information system supporting all management activities in the life cycle of software.Adequate management of the production and maintenance of software can be achieved only with the support of quantitative analysis. This analysis must examine all attributes of the process by which software is developed and maintained. Initial results are available of an investigation into the use of quantitative models within an SPMMS.There are several issues and problems of project management. Existing models for cost and some approaches to the measurement of quality have disadvantages. An experience database helps estimating and planning and control. Criteria for model selection can be given (as a basis for assessing external and internal models). A CQA model is incorporated within SPMMS. This is part of the SPMMS approach to integrated and automatic management support.     

A rule-based expert system approach to process selection for cast components

A knowledge-based expert system at the discretion of casting product designers can be employed as a real-time expert advisor to assist product designers to achieve the correct casting design and select the most appropriate casting process for a given component. This paper proposes a rule-based expert system approach for casting process selection, and describes an ongoing rule prototype development. The system in its present development state consists of five interconnected levels each concerning a particular process selection parameter or group of parameters including alloy to be cast, casting geometric features, casting accuracy, production quantity and overall comparative costs. The system progressively evaluates the user's specifications against the capabilities of various casting processes and in each level selects the processes that satisfy the design parameters specified. The final comparative cost level compares the processes that have satisfied all the criteria in the previous levels and recommends the most economical option.     

Maintenance considerations in CIM design: An expert system perspective

An unmanned manufacturing system (UMS) will typically be characterized by a large number of highly reliable components which are interconnected in a highly complex fashion. These characteristics suggest: (1) there will be a large number of ways in which a UMS can fail; (2) the mean time between repeat occurrences of a given type of problem will be quite large; and (3) the time and place where a failure creates an observable symptom may be quite different from the time and place where the failure occurred. This suggests that an UMS could be difficult to maintain. Maintenance personnel obviously need assistance for dealing with the complex cognitive problems which can arise in troubleshooting the UMS. This paper describes a procedure for developing an expert system to provide this assistance. Simulation is utilized to generate proxy data on how the system could be expected to behave when a given type of failure occurs. Transfer-function/intervention analysis is utilized to develop models which describes the system transient response to the various types of failures. Failure problems are diagnosed by comparing the shape of the actual transient response with the shapes of transient responses which correspond to the various types of failures.     

Designing wire-rope-based mechanical systems in an expert system environment

This paper presents concepts related to the development of an expert system suitable for wire-rope-based mechanical system design. The design of mechanical systems with wire ropes, involving the selection of a wire rope and its supporting structure, is currently accomplished by implementing a cataloged solution for the given application and is typically performed without benefit of detailed analysis. For the most part, resulting systems reflect the wire rope engineer's preferences and experience with various wire rope configurations and designs. The current study presents concepts for an expert systems approach to the design problem that utilizes recently developed, detailed wire rope analysis capabilities. Thus the expert system not only incorporates the expertise in the form of rules but also interacts with analysis packages for design development. It is believed that wire rope systems designed in this manner may prove less costly to manufacture and have lifetimes exceeding those currently specified for most applications.