An expert system for the optimal mesh design in the hp-version of the finite element method

This paper suggests a simple expert system frame and provides the domain knowledge for the optimal mesh design and the prediction of the error in the energy norm for the problem of plane elasticity using the hp-extension in the finite element method. The expert system monitors the progress of the analysis, guides the user through the various steps and is able to reason about its own advice. In an example the user–expert communication is shown and the superiority of the results is demonstrated.     

基于专家系统的振动台振级调整算法的研究

振动台振级调整算法是振动校准自动控制系统中的关键技术。本文结合人工操作振动台的控制策略,提出了一种基于专家系统的振动台振级调整算法,并在LabVIEW环境下采用图形化编程实现了基于该方法的振级调整自动控制系统。试验结果表明,基于专家系统的振动台振级调整算法能得到良好的控制效果,该算法满足振动校准过程高精度与智能化的要求,提高了校准系统的效率和自动化程度。     

An economic model for determining the optimal quality and process control policy in a queue-like production system

This paper interrelates and synthesizes the economic design of quality and process control policy and the management of a production system described in terms of an M/G/X queue. A mathematical model is developed to determine the optimal quality and process control policy when both the quality and quantity issues in the production system are considered. The optimal control policy is defined as the one that maximizes the expected profit per unit time over an infinite horizon. Hypothetical data is used to illustrate the impact of on-line control policies on the operating characteristics of the production process.

For a given control policy, it is shown that the expected profit per unit time of the production system can be increased by either improving the reliability of the production system, increasing the arrival rate of incoming jobs, increasing the system's processing rate, or shortening the system's shutdown time. The results also indicate that the larger the performance difference between the in-control and the out-of-control states, the greater the amount of effort should be involved in quality and process control. Finally, it is important for the capacity design of a production system to take into account the requirrments for both quality control and process adjustment.     

产品设计专家系统研究

介绍了产品设计的目的和任务,信息时代的产品设计发展状况及存在的问题,讨论了将人工智能理论与专家系统技术应用于产品设计领域,提出一个产品设计专家系统的框架结构.利用智能代理技术实现了信息与资料的整理,依据形态分析法实现了辅助创新设计,并提出采用数学建模法进行产品方案的评定.     

Hybrid expert system for the failure analysis of mechanical elements

An expert system for the failure analysis of metallic mechanical components is described, with emphasis on the structure and the solution strategy followed by the software. The system treats failure in common mechanical elements and is aimed to guide non-experts through the process of basic failure analysis. The system acts as a “virtual colleague”, providing guidance and experience during failure studies. As such, it allows the users to gradually increase their experience while using the software in distinct applications. The system works interactively through a system of structured questions. The answers provided by the user permit the software to direct the analysis toward its solution. Decisions are taken in a hybrid way, through case based reasoning and rule based reasoning, the former using a database of solved cases, the latter mimicking the way experts treat failure analysis. The paper describes the development method, the logic behind the operation of the system and the interaction between case based reasoning and rule based reasoning modules. Its performance in four real-world failure cases is used to demonstrate its feasibility and usefulness.     

An expert system for hydrocarbon pyrolysis reactions

The behaviour of complex chemical reactions such as the cracking of hydrocarbons may be represented by a set of differential equations each of which corresponds to a mass balance over a single elementary species, reactant or product. The simulation of the overall reaction is achieved by numerical integration of this set of equations. For reactions such as combustion and pyrolysis of organic molecules the number of elementary reactions is very large indeed and in order to produce a viable model of the reaction it is necessary to produce a subset that approximates to the behaviour of the real system.We have developed an expert system on a VAX11/780 that generates reaction mechanisms on the basis of a generator of elementary reactions that is constrained by rules relating to initial conditions and kinetic and thermodynamic data. Chemical species are represented by PROLOG lists that can be manipulated in a variety of ways in order to generate reactions such as dissociation, abstraction, combination etc. The emphasis of the system is on eliminating unproductive reactions at an early stage in order to avoid the generation of hundreds of redundant reactions.The mechanisms generated so far for small acyclic hydrocarbons compare favourably with those produced by human experts. It appears that some relatively straightforward extensions of the existing system will result in a powerful tool for the investigation of complex reactions and the evaluation of kinetic data.     

An expert system for network management control

Abstract

Due to the varying time and the complexity of the commercial telecommunication network configuration, routing of the communication traffic becomes very important for telecommunication systems. No one can keep in mind all the complex routing plans used in networks, so it is hard to quickly take proper actions while the switching node is being blocked.

In this paper, we propose an expert system which can collect traffic data, monitor network status, reason and take appropriate actions for extreme traffic congestion on a network just as a network management expert can do. It would certainly streamline the whole network control procedure, and. provide dynamic routing functions based on the original static routing method adopted in Taiwan. It does improve both network efficiency and network reliability.     

Integrated model for determining the optimal initial settings of the process mean and the optimal production run assuming quadratic loss functions

Chen and Chung (1996 Chen, SL and Chung, KJ. 1996. Determining the optimal production run and the most profitable process mean for a production process. International Journal of Production Research, 34: 2051–2058.  ) addressed the problem of the joint determination of the optimal process mean and production run for an industrial process. Their study considered a product with an upper and a lower specification limit. The optimal process mean and optimal production run were obtained by balancing the profit of meeting and not meeting the specification limits. However, Chen and Chung did not consider the quality cost for the product within the specification limits. The present paper revisits the problem and incorporates the quality cost by introducing a Taguchi loss function for determining simultaneously the optimal process mean and production run. As per Chen and Chung, the present paper assumes a 100% inspection scheme. It also investigates the differences between Chen and Chung's approach and the Reward Theorem approach. A sample inspection scheme is also proposed. Numerical examples are provided to demonstrate the application of the model. A sensitivity analysis of the model is provided. Some new directions for further research are also outlined.     

Iterative algorithm for determining optimal beam profiles in a three-dimensional space

A new, to our knowledge, iterative algorithm for achieving optimization of beam profiles in a three-dimensional volume is presented. The algorithm is based on examining the region of interest at discrete plane locations perpendicular to the propagation direction. At each such plane an intensity constraint is imposed within a well-defined transverse spatial region of interest, whereas the phase inside that region as well as the complex amplitude outside the region is left unchanged from the previous iteration. Once the optimal solution is found, the mask that generates the desired distribution can be readily implemented with a planar diffractive optical element such as a computer-generated hologram. Several computer simulations verified the utility of the proposed approach.     

A method for determining the stress intensity threshold level for fatigue crack propagation

The influence of a decreasing rate of stress intensity factor with crack propagation, $\text{d}\text{K/}\text{d}\text{a}$, on a stress intensity threshold level, $\text{δK}{}_{\mathrm{th}}$, below which fatigue crack propagation becomes insignificant is investigated. Specimens, 200 mm wide, 10 mm thick with a 40 mm-long central crack, are fatigued at the decreasing rates, $\text{∥}\text{d(δK)}\text{d}\text{a∥}$, of 2,44, 5 and 10 kg/mm^5/2 with a peak load control system and a pair of crack followers. In this range of $\text{d}\text{(δK)/}\text{d}\text{a}$, the stress intensity threshold levels, $\text{δK}{}_{\mathrm{th}}$, have the same value regardless of $\text{d}\text{K/}\text{d}\text{a}$. Therefore, the present method of decreasing the stress intensity factor at a constant rate is suitable for determining the characteristic $\text{δK}{}_{\mathrm{th}}$ of materials. Furthermore, the influence of stress ratio, $\text{R}$, is investigated at the decreasing rate, $\text{∥}\text{d}\text{(δK)/}\text{d}\text{a]}$, of 10 kg/mm^5/2.     

An expert system for the design and analysis of composite structures

A prototype expert system is described for concurrent design and analysis of composite structures. This system integrates symbolic, numerical and knowledge-based tools in an object-oriented programming environment for design synthesis, evaluation and modification. The system determines structural behavior utilizing a combination of analytical and numerical tools. Design modifications and structural optimization are performed using heuristic and experientially derived knowledge bases. The different domain-specific programs and commercial packages utilized by the system are integrated using a generic interfacing mechanism. The utility of the system is demonstrated by means of a design case study for a typical aircraft or rotorcraft structural component.     

An expert system for preliminary numerical design modelling

This paper is based upon the premise that computers can do more than just ‘number crunching’ to assist a designer in his task. Key features of the design process where traditional computer-aided design (CAD) approaches have had limited success are presented. The approach of expert systems, which shows promise of assisting in these features, is outlined and a system based on this approach, DESIGNER, described. This system can be applied to any numerical design problem and is illustrated through an example from preliminary ship design.     

真空冶金设备抽气装置专家系统及应用实例

介绍了专家系统的特点和应用,分析了大型真空冶金抽气装置的特性、故障多发原因以及排查中的困难,指出采用专家系统的可行性和实际意义,明确了在真空冶金抽气装置中建立专家系统的具体内容.以宝钢RH-KTB炉外精炼真空系统为例,给出了设备运行监测方案,建立了专家系统知识库,编制的软件可对设备的运行状态进行即时评价和故障预报,当真空系统出现故障时,采用逆向推理机制,从目标出发,寻找故障可能原因,并给出推理解释.专家系统对监测参数阈值的机器学习,提高了专家系统实际应用中的推理效率和准确性.专家系统软件经离线测试和现场在线应用达到预期的目标,可以推广应用.     

An automatic method of determining the level of molten substances

Conclusions The measuring circuit of the level indicator was tested out on a cold (water) model of the instrument which made it possible to measure directly the liquid level in the tank. The measurement error was due mainly to the failure to observe accurately condition (4) and to the grade of accuracy of the instrument, which amounted to 1.5% of the maximum level, fixed at 50 cm for this experiment.When operating with an actual oven the error rises (according to tentative calculations) by a factor of 1.5 to 2.5 due to the additional temperature errors.The measuring range depends on the electrodes used and can amount to 1-1.5 m. The measuring time depends entirely on the servo-motor of the bridge.The above level indicator can be used for a continuous automatic measurement of the level of metal (slag) in laboratory installations or industrial metallurgical ovens.     

FMS Designer: An expert system for flexible manufacturing system design

Implementation of flexible manufacturing technology in the batch manufacturing environment has created major problems for designers and engineers who are responsible for specification and design of flexible manufacturing systems (FMS). The FMS design task appears to be an excellent application for expert systems techniques. This paper describes current results of an ongoing research effort to develop an expert system which analyses the output from an FMS simulation model, determines whether operational and financial objectives are met, identifies design deficiencies or opportunities for improvement, and proposes designs which overcome deficiencies or exploit improvement opportunities. An overview of the FMS design expert system is given and a case study is presented to illustrate how the system operates. Areas for future research are also discussed.     

An expert system for the design and selection of ball bearing parameters

Artificial Intelligence (AI) is an emerging technology. Research in Al is focused on developing computational approaches to intelligent behaviour.The computer programs with which AI could be associated are primarily processes associated with complexity, ambiguity, indecisiveness, and uncertainty. One of these computer programs is referred to as Knowledge-based Expert System (KBES) as it represents knowledge acquired from various experts in a particular field of interest to the user. The expert system emulates human behaviour in solving problems thought to require experts for their solution by utilizing computer programs that incorporate experts' heuristic reasoning. In this paper, the application of KBES to aid the design of ball and roller bearing is discussed. The precision rolling-element bearing of the twentieth century is a product of exacting technology and sophisticated science. A bearing supports radial and axial loads, at the same time allowing relative motion between two elements of a machine. Various requirements and steps in the design of ball and roller bearings are discussed. Equations are developed for the relevant design parameters and input into the expert system shell called VP-Expert. The expert system rules are also provided.     

Issues in expert system development

The explicit representation of domain knowledge and its separation from the processes which manipulate it and the representation formalism particular to artificial intelligence allow expert systems to solve problems which are characterized by a high combinatoric complexity or which are sufficiently ill defined as to not have reasonable software engineering solutions. The expert system approach to problem-solving differs radically from its conventional system development counterpart. This paper defines the expert system and introduces the production system architecture. The relative strengths and weakenesses of expert system and software engineering approaches to problem solving are discussed. Also addressed are criteria for identifying problems amenable to expert system solution and some justifications for system development.Paper presented at the Ninth International Thermal Expansion Symposium, December 8–10, 1986, Pittsburgh, Pennsylvania, U.S.A.