Structural design language for coupled knowledge-based systems

A Structal Design Language (SDL) has been developed in INTERLISP environment for building coupled knowledge-based expert systems for integrated design of a class of structures. The integrated design includes the preliminary design, structural analysis, design of members, design of connections, and computer-aided drafting of the final design. The complex body of knowledge needed for detailed design of a structure is fractionated into smaller and more manageable knowledge sources which are organized into a hierarchy of cooperating conceptual specialists. SDL provides a multiwindow graphics interface capable of displaying both the orthographic and isometric views of the frame structure and beam-column connections. A three-dimensional face frame representation sentation is used for the graphic display of the beam-column connections. SDL has been used to develop a prototype knowledge-based system for integrated design of steel building structures consisting of moment-resisting frames.     

Architecture of a coupled expert system for optimum design of plate girder bridges

A prototype knowledge-based expert system has been developed for optimum design of steel plate girders used in highway bridges. This expert system, called PG-BRIDGE1, is a coupled system in which AI-based symbolic processing is combined with the traditional numerical processing. Plate girders can be unstiffened or stiffened with single- or doublesided transverse stiffeners. They can be homogeneous or hybrid, made of high-strength flange plates and low-strength web plate. A mathematical optimization algorithm has been developed for minimum weight design of plate girders using the generalized geometric programming technique. The basis of design is the American Association of State Highway and Transportation Officials (AASHTO) specifications. The plate girders are subjected to the live (moving) loads of the AASHTO specifications. The knowledge base and symbolic processing has been developed using the Expert System Development Environment (ESDE). Numerical processing for structural analysis, optimization algorithm and graphics interface have been developed in FORTRAN 77.     

Knowledge engineering in the computer-aided design of control systems

Abstract: MAID is an expert system for the computer-aided design of control systems. It is developed in conjunction with the successful application of a systematic control system design technique. The design problem has been decomposed into sub-problems, resulting in good modularity of design knowledge. Interactive design and the designer's intuition are emphasized. MAID, which acts as a designer's assistant, was developed using the expert systems development facility provided within a control system design package. The coupling of symbolic and numerical processing was carried out in a natural way.     

Quantitative knowledge based approach for preliminary design of tall buildings

A knowledge based expert system for the preliminary design of tall buildings has been developed. The system implementation is based on the integration of symbolic and numerical processing. A domain independent shell has been employed in the expert system development and verification. The rule based knowledge base of the system includes a set of IF/THEN rules that provide the inference mechanism with the information needed in the judgemental process. A numerical algorithm is introduced to help quantify the decision making process by relating the confidence factors for each possible solution to a numerical quantity defined as the virtual number of stories. The judgemental process is coupled with the numerical algorithm through the external program facility provided in the expert system development shell.     

An expert system on design of liquid-retaining structures with blackboard architecture

Abstract: The design of liquid‐retaining structures involves many decisions to be made by the designer based on rules of thumb, heuristics, judgement, codes of practice and previous experience. Structural design problems are often ill structured and there is a need to develop programming environments that can incorporate engineering judgement along with algorithmic tools. Recent developments in artificial intelligence have made it possible to develop an expert system that can provide expert advice to the user in the selection of design criteria and design parameters. This paper introduces the development of an expert system in the design of liquid‐retaining structures using blackboard architecture. An expert system shell, Visual Rule Studio, is employed to facilitate the development of this prototype system. It is a coupled system combining symbolic processing with traditional numerical processing. The expert system developed is based on British Standards Code of Practice BS8007. Explanations are made to assist inexperienced designers or civil engineering students to learn how to design liquid‐retaining structures effectively and sustainably in their design practices. The use of this expert system in disseminating heuristic knowledge and experience to practitioners and engineering students is discussed.     

Virt: A universal programming language

Conclusion The language VTRT has been implemented in Borland Pascal as a protected-mode MS DOS interpreter. The integrated development environment program includes a special-purpose text editor and a debugger, which allows stepwise tracing of the program at the source code level and the pseudocode level, executes the program up to an interrupt point, and ensures full control over all interpreter components (symbol table, stack, heap). VIRT has been tested in practice and a library of various applications has been developed: numerical methods, graph algorithms, symbolic processing and knowledge representation, automatic theorem proving. To test the possibilities of crosslanguage cooperation, a DLL library of graphic procedures was created in Borland Pascal, and an interface module was written in VIRT. In this way, several specific applications have been developed using VERT tools. The most promising directions for further study of VIRT include construction of database management systems, construction of case systems, construction of interpreters for functional languages, and knowledge processing. Of special interest is the use of VIRT to solve artificial intelligence problems. Note that arrays in VIRT are even better adapted to the needs of symbolic processing than lists in Lisp. Indexed access gives a definite advantage to the use of iterative procedures compared with recursive programming. An arbitrary list can be efficiently represented by a VIRT array, but not conversely. VIRT provides a single language environment for problems of various profiles (numerical calculations, symbolic processing, deductive inference, user interface) that require integration into a single system. Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 130–150, September–October, 1998.     

Interactive microcomputer-aided design of shop-welded and field-bolted beam-column connections

A microcomputer-aided design (MicroCAD) system has been developed for interactive design of connections in steel buildings made of standard rolled l-sections, called Steelcon. Design of different connections is based on the American Institute of Steel Construction specification. Connecting elements may be plates, angles, or T-sections. Connectors may be bolts or welds. The MicroCAD system can display/plot any isometric view of the connection plus the orthographic views, i.e. front, side, and top views. The application of the MicroCAD system to the design of simple (type 2) shop-welded and field-bolted beam-column angle and plate connections is discussed. Microcomputer graphics for displaying the isometric and orthographic views including the dimensions and designation are presented. This MicroCAD system can be used effectively for practical design of connections in steel buildings.     

催化知识智能处理的初步研究

应用专家系统技术处理催化剂设计中大量非数值信息具有重要的实用价值。本文采用专家系统工具M.1,通过一个“离子浸渍吸附”子系统的原型构造实例,讨论催化知识构成和相应的处理方法。在此基础上,提出了结合传统的数值模拟技术构造催化专家系统的设想。     

A blackboard architecture for plastics design

Engineering design is a complex, ill-structured problem involving vast amounts of knowledge that often deal with incomplete, and uncertain, information. The design process typically involves a number of sub-tasks, some of which are amenable to numeric or algorithmic processing (e.g., analysis and optimization); most other sub-tasks require symbolic processing, and are typically solved by expert designers who rely on experiential knowledge used in the form of heuristics. The latter set of sub-tasks were chiefly responsible for creating the symbolic bottleneck that has set back the efforts to automate the design process. However, with the advent of recent AI methodologies we now have techniques for tackling the symbolic bottleneck. Even though some progress has been made in this area with the aid of knowledge-based expert systems, many important questions still remain to be research. In the DESIGNER project we are performing empirical studies that focus on these questions using the plastics design problem as our test bed. We have focused on the preliminary or the base-case design in this domain and have implemented a working prototype called DESIGNER, based on the blackboard architecture. This paper discusses the various aspects of DESIGNER, which is a hybrid, integrated, conferring expert system (HICEX). We are currently extending DESIGNER's capabilities to address the other aspects of the plastics design problem such as part design, plastics processing selection, etc. We are also investigating decentralized communication architectures for integrating multiple experts on the design problem.     

Computer-aided design of structures using LISP

An experimental knowledge-based expert system, called SSPG. is presented for design of stiffened steel plate girders, using the LISP programming language. Employing previously acquired knowledge of the optimum span-to-web depth ratios, SSPG is capable of yielding a “practical” minimum weight design without performing a costly formal optimization. This research indicates the effectiveness of the LISP language for computer-aided design of structures where not only subjective knowledge and heuristics are needed but also substantial numerical computations are involved.     

Symbolic and numeric knowledge integration in multiple fault troubleshooting

Many expert system researchers have reported in recent years that situation-action symbolic production rules frequently fail to provide adequate knowledge representation schemes without resorting to numeric computation. However, despite the need to integrate symbolic and quantitative computation into one coherent framework of knowledge, surprisingly few architectures have been proposed for achieving this goal. This paper explores the integration of qualitative and numeric processing in expert systems. We address the topic with respect to the construction of expert systems that perform the tasks of design and multiple fault troubleshooting. This paper shows that these tasks can be handled effectively when an appropriate interface is established between the heuristic and the numeric knowledge-based components. Specifically, we demonstrate how to interface heuristic knowledge with non-linear optimization models in order to allow an expert system greater expressiveness. An actual example is presented from the machining domain.     

Heuristic, symbolic logic and knowledge-based approach to the design and construction of buildings

The emergence of knowledge-based expert systems provide means with which one can use the computer as an aid to the solution of an ill-structured problem. Expert systems are interactive computer programs based on heuristics, incorporating judgement, rules of thumb, intuition and expertise to provide knowledgeable advice about variety of tasks. Such specialized interactive computer programs can broadly be classified as (1) identifying the relevant design knowledge, (2) providing a formalism for representing and processing the knowledge and (3) implementing the formalism in a computer environment. While the first issue of identifying the relevant knowledge is through knowledge acquisition from various domain experts and verification of the same by other domain experts. The second issue is proper formalism for the varied knowledge requiring the use of logics (prepositional calculus) as a symbolic language; heuristics or rules of thumb wherever necessary and a suitable reasoning methodology, i.e. an inference technique. The third issue is the evaluation of a suitable strategy for successful computer implementation, i.e. the computer problem is subdivided into smaller tasks which have easy solutions; and the capability of interacting the solutions of the smaller tasks into a larger framework. Therefore, this will require theorem proving, search technique and a special purpose computer language such as PROLOG or readily available domain independent shells, i.e. expert system tools. The overall synthesis of all the above is termed as a knowledge-based expert system (KBES). In this paper a KBES is developed for a highly complex building element, ‘beam design’, as part of a larger model involving planning, analysis, design, optimization and cost forecasts along with other allied services such as plumbing and electrical services. In the development of KBES; the knowledge-base is purely heuristic and subjected to alteration by numerical calculations. For an effective search the modified depth technique is adopted. Heuristics are employed to further the search as and when required from the point of view of practical computer implementation. In the overall development, use is made of dependency diagrams, charts, tables and search trees. For computer implementation the necessary tool chosen was the M1 shell developed by Teknowledge Inc., U.S.A. This requires a PC-AT with 640 kB RAM and 40 MB hard disk. A brief overview of the expert system, followed by an example problem, is presented.     

AN INTELLIGENT DECISIONMAKER FOR OPTIMAL CONTROL

We present an expert system that can handle various complicated decision-making problems of optimal control that are hardly solvable manually or even by computer-aided design techniques. The expert system is the first implementation of solving decision-making problems of optimal control using a computer, which paves the way for us to develop the real-time intelligent optimal control environment. Through a user-friendly interface, the expert system can receive the needed information from the user, perform heuristic search, and provide the results of a decisionmaker quickly both on the screen and from a printer. The important features of this expert system are that it () makes a decision on the problem-solving strategies for optimal control, that is, provides the solution structure and transversality conditions as well as types of some key equations; (2) processes symbolic information; (3) breaks down the whole search into three reasoning levels such that the problem can be solved easily and the search routine can be simplified; (4) utilizes “filter rules” to reduce production rules and enhance the program efficiency; (5) modifies the knowledge base and creates new rules in production rule memory; and (6) applies a “certainty factor” to represent imprecise knowledge. The expert system has been implemented using the AI tool OPS5 on a VAX 11/780 computer running under VMS. An example is also used to illustrate our expert system.     

Automated knowledge acquisition for design and manufacturing: The case of micromachined atomizer

In order to remain competitive in the global market, original equipment manufacturers (OEMs) are developing a process-based, knowledge-driven product development environment with emphasis on the acquisition, storing, and utilization of manufacturing knowledge. This is usually achieved by using the symbolic artificial intelligence (AI) approach. Specifically, knowledge-based expert systems are developed to capture human expertise, mostly in terms of IF–THEN production rules. It has been recognized that the development of symbolic knowledge-based expert systems suffers from the so-called knowledge acquisition bottleneck. Knowledge acquisition is the process of collecting domain knowledge and transforming the knowledge into a computerized representation. It is a challenging and time-consuming process due to the difficulties involved in eliciting knowledge from human experts. This paper presents an automated approach for knowledge acquisition by integrating neural networks learning ability and fuzzy logics structured knowledge representation. Using this approach, knowledge is automatically acquired from data and represented using humanly intelligible fuzzy rules. The approach is applied to a case study of the design and manufacturing of micromachined atomizers for gas turbine engine. The influence of geometric features on the performance of the atomizers is investigated. The results are then compared with those obtained using traditional regression analysis approach (abstract mathematical models). It was found that the automated approach provides an efficient means for knowledge acquisition. Since the fuzzy rules extracted are easy to understand, they can be used to allow more clear specification of manufacturing processes and to shorten learning curves for novice manufacturing engineers.     

Designing on‐demand education for simultaneous development of domain‐specific and self‐directed learning skills

On‐demand education enables individual learners to choose their learning pathways according to their own learning needs. They must use self‐directed learning (SDL) skills involving self‐assessment and task selection to determine appropriate pathways for learning. Learners who lack these skills must develop them because SDL skills are prerequisite to developing domain‐specific skills. This article describes the design of an on‐demand learning environment developed to enable novices to simultaneously develop their SDL and domain‐specific skills. Learners received advice on their self‐assessments and their selections of subsequent learning tasks. In the domain of system dynamics – a way to model a dynamic system and draw graphs depicting the system's behaviour over time – advice on self‐assessment is provided in a scoring rubric containing relevant performance standards. Advice on task selection indicates all relevant task aspects to be taken into account, including recommendations for suitable learning tasks which meet the individual learner's needs. This article discusses the design of the environment and the learners' perceptions of its usefulness. Most of the times, the learners found the advice appropriate and they followed it in 78% of their task selections.     

Rule-based design of a material processing component

The main thrust of this research is in developing aknowledge-based system for the design of components for a material processing system. In particular, this paper concentrates on developing methodologies forinitial design andredesign in a quantitative and qualitative format. A die for plastic extrusion has been selected as the subject material processing component. A design algorithm using best first heuristic search and expert knowledge, both in procedural and declarative form, is the core of the scheme. Apart from this expert, the suggestedselection procedure for candidate design is also seen to accelerate the design scheme. The methodologies presented enableefficient design of the component. Some generality has been accomplished by the implementation of the techniques to dies of different cross-sectional shapes. The software is written inLisp within an object-oriented software package using analysis modules written in C.     

设备诊断型专家系统的一种开发工具

本文设计了一种用于开发诊断型专家系统的工具系统.该系统能完成知识获取、一致性 检测和诊断推理等任务.它具有使用变量、常量和函数来描述领域知识、集成符号推理和数值 计算等特点.该系统用Microsoft C5.0语言在IBM微机上得以实现.     

DEVELOPMENT OF AN INTELLIGENT PRODUCT DESIGN SYSTEM: INTEGRATION STRATEGIES

Conventional computer-aided design (CAD) packages have drastically reduced the workload of the human designer and shortened the product design cycle. However, the degree of effort and volume of information required to use these tools limit their use to the later stages of design. Intelligent computer-aided design (ICAD) systems have sought to provide a more complete design tool to assist the designer in all phases of design. ICAD systems incorporate conventional CAD elements as well as knowledge engineering constructs. The level of integration between different components of an ICAD system determines its usefulness. Most commercial intelligent CAD packages are tied to a specific set of CAD tools, restricting their application domains. This dependence on specific software tools can be reduced by using general purpose modules to interface with available CAD packages. This paper discusses a method of introducing knowledge engineering technology to help develop an advanced intelligent product design system by integrating ICAD's Concept Modeller with SDRC's l-DEAS package for engineering product design. This integration is necessary because neither the Concept Modeller nor the I-DEAS package provides any unified design environment where users can access both symbolic and numerical design tools as needed to carry out design synthesis and analysis activities. Interfacing engineering design and knowledge processing together is not an easy task. The task is further complicated since it needs to be done only by those who have enough knowledge of both technologies, and also because it may result in reorganization of the traditional design process altogether. The proposed intelligent product design system uses artificial intelligence techniques to take care of human experts knowledge and it advocates the use of several commercial software packages that come from a variety of sources (and are proven to be robust) to perform design synthesis in a cost-efficient and timely manner. The technique described here is relatively easy to implement and is well suited to industrial needs.     

An online expert system for fault diagnosis in hydraulic systems

Fault diagnosis has become increasingly important for industrial automation and many approaches have been investigated for the online diagnostic task. This work demonstrates a new online expert system for dynamic industrial automated processes. The emphasis of this diagnostic system lies in the functions provided for fault detection, prediction, compensation and diagnosis. The system uses experiential knowledge cooperatively with scientific knowledge in a new interactive formation. It is developed in two parts using the DASYLab software for the numerical computations and the KPWin development tool for the symbolic representations. The system was developed in collaboration with the company Automation Systems S.A., which specializes in hydraulic systems, and is used for fault detection in production machines.     

NUREST:一个实时专家系统开发工具

对实时专家系统的特点作了概要论述,将专家系统技术和实时控制技术相结合,设计并实现了应用于实时问题求解的实时专家系统开发工具NUREST。主要讨论了它的知识表示、实时控制机制、推理机制以及实现技术,并给出了开发的炼钢控制实时专家系统实例。