Computer-aided design for manufacturing process selection

This paper describes an expert system that helps designers select a manufacturing process in the early stage of product design. First, the paper focuses on net-shape manufacturing processes and identifies the major factors that affect the selection of an appropriate process. Examples of these factors include shape, production volume and material. A versatile methodology should consider all the factors simultaneously in assessing the suitability of the candidate processes. The proposed system uses the concept of design compatibility analysis to represent the suitability of candidate processes with respect to the given product specifications. The system uses this knowledge to eliminate incompatible candidates and rank the compatible set of processes. A prototype system called DFPS uses HyperCard and Prolog to implement the proposed methodology. DFPS also contains information related to each process.     

Prospects for process selection using artificial intelligence

On problem facing modern industry is the lack of a skilled labor force to produce machined parts as has been done in the past. In the near future, this problem may become acute for a number of manufacturing tasks. One such task is process planning. Since process planning requires intelligent reasoning and considerable experiential knowledge, almost all existing computer aided process planning systems require a significant amount of supervision by an experienced human being.There is some prospect that “expert computer system” techniques from the field of Artificial Intelligence may be successfully used to automate (at least partially) several of the reasoning activities involved with process planning. This paper discusses some current prospects for automating a process planning task known as process selection. These ideas are currently being considered for use int he Automated Manufacturing Research Facility project at the U.S. National Bureau of Standards, and steps are being taken to implement them in an expert computer system.     

The design process of expert systems development: some concerns

Abstract: A discussion is presented of why some expert systems that organizations have developed are not successful. The concept of design process plays a very significant role at the outset of the expert system development process. This concept has not been the subject of much debate and attention in expert systems development. From the author's point of view, one of the main issues is how the designer (knowledge engineer) thinks about the design process. In general, the designer's process is influenced by the knowledge engineer's conception. This paper endeavors to disclose some of the main factors related to the knowledge engineer's conception of the design process and an attempt is made to put forward a conceptual model of the expert system design process. This conceptual model is an initial step towards a successful implementation of expert system projects.     

Process selection for the design of aluminum components

This paper describes a method for process selection of aluminum components in the early stages of design. Aluminum has many advantages in a variety of applications in its manufacturability and recyclability. Yet, engineers who are trained to design steel components do not take full advantage of this material. The main reason is that engineers tend to be unaware of the many economical processing methods for aluminum. We have developed a program that combines preliminary screening of processes with normalized cost analysis. Design compatibility analysis (DCA) ranks each process based on its feasibility with the basic geometry, material, and production requirements. For top candidates, the program employs external cost routines for detailed comparisons. The primary processes considered are extrusion, sheet forming, forging, die casting, and sand casting. The program extends its compatibility and cost analysis to secondary operations such as bending and machining. The program should be useful for engineer training and as a preliminary design tool. The program uses HyperCard as a front-end, Prolog for logic-based analysis, and Excel for cost calculations.     

A decision support system for material and manufacturing process selection

The material and manufacturing process selection problem is a multi-attribute decision-making problem. These decisions are made during the preliminary design stages in an environment characterized by imprecise and uncertain requirements, parameters, and relationships. Material and process selection decisions must occur before design for manufacturing can begin. This paper describes a prototype material and manufacturing process selection system called MAMPS that integrates a formal multi-attribute decision model with a relational database. The decision model enables the representation of the designer's preferences over the decision factors. A compatibility rating between the product profile requirements and the alternatives stored in the database for each decision criteria is generated using possibility theory. The vector of compatibility ratings are aggregated into a single rating of that alternative's compatibility. A ranked set of compatible material and manufacturing process alternatives is output by the system. This approach has advantages over existing systems that either do not have a decision module or are not integrated with a database.     

An expert system for the selection of software design patterns

Abstract: This paper describes the development of a prototype expert system for the selection of design patterns that are used in object-oriented software. Design patterns provide one method of software reuse, which supports the goal of improved software development productivity. The prototype system represents an initial step towards providing an automated solution regarding the design pattern application problem, i.e. leading a designer to a suitable design pattern which is applicable to the problem at hand. The feasibility of using expert system technology to aid in the selection problem is demonstrated.     

CAD for process plants: an update

We review the availability of CAD software for the process design activities of physical properties generation, unit operation design, flowsheeting and dynamic flowsheet simulation. Similarly we look at CAD software for materials control, piping documentation and pipe stressing. We report conclusions drawn from our research into the provision and use of CAD turnkey systems for producing schematics at the conceptual design phase, and for equipment specification, layout, piping design and 3D modelling at the engineering design phase.By reviewing the shortcomings of current CAD systems along with developing CAD technology, we were able to specify the requirements of the next generation of process plant CAD.     

关系数据库技术在计算机网络设计中的运用

随着我国社会经济建设水平的不断提高和计算机网络技术的推广普及,关系数据库技术在计算机网络设计中的运用成为社会各领域关注的焦点,本文将从关系数据库技术的角度出发,结合计算机网络设计的实际,对关系数据库技术在计算机网络设计中的运用进行深入的研究和探讨。     

数据质量模型及选择运算中的质量传播研究

针对数据库数据质量评价问题,给出了一个属性粒度的质量评价模型,定义了正确性评价指标。在分析量化前后属性错误率的基础上,给出了两种错误率之间的关系。还研究了关系代数选择运算在键属性条件下的质量传播关系,得出了选择运算前后正确性不变的结论,并分别用属性量化前后错误率进行了表示。     

A process model for interactive systems

Designing user interfaces and designing computational software are very different processes. The differences lead to late discovery of design conflicts, which drives up development costs. A unifying methodology that could provide early discovery and resolution of design conflicts must account for the governing principles of both processes. Disciplined long-term investigation of candidate methodologies requires that these governing principles be fixed and that evolving development methods comprising each process be accommodated. This article describes an application of general systems theory to integrate these principles, proposes a process model that fixes them as explicit elements of a process program, argues the feasibility of the model and its worthiness for further study, and describes its initial implementation.     

基于FCD扩展的多构件选择过程

大型软件系统中的构件间存在依赖关系,因此难以对单个构件独立进行评估。现有的方法大多针对单个构件,并不适合多个构件的评估和选择。对一种成熟的系统分解方法FCD进行扩展,提出了一种针对多构件进行评估和选择的方法。在系统分解的过程中识别出局部需求和横切需求。局部需求被分解到各个模块中作为对候选构件进行局部评估的准则,横切需求则进入全局评估。系统分解的过程中,需求吸取识别出来的现有构件的特征,从而进一步精化,同时考虑到不同粒度的构件的组合。全局选择被定义成为一个在给定约束条件下选择出一组具有最大的全局需求满足度的最优构件组合的非线性优化问题。     

A distributed expert control system for a hydrometallurgical zinc process

A distributed expert control system (DECSHZ) has been built for a hydrometallurgical zinc process, whose basic steps are leaching, purification and electrolysis. It consists of a central computer management system and three local expert control systems, one for each of the basic steps. This paper deals with the design and application of DECSHZ, especially its distributed architecture and main functions; expert control strategies based on rule models and a combination of rule models and steady-state mathematical models; system implementation; and the results of actual runs. DECSHZ has been found to provide not only a very pure product, but also significant economic benefits.     

Simultaneous optimal selection of design and manufacturing tolerances with alternative manufacturing process selection

Tolerance specification is an important part of mechanical design. Design tolerances strongly influence the functional performance and manufacturing cost of a mechanical product. Tighter tolerances normally produce superior components, better performing mechanical systems and good assemblability with assured exchangeability at the assembly line. However, unnecessarily tight tolerances lead to excessive manufacturing costs for a given application. The balancing of performance and manufacturing cost through identification of optimal design tolerances is a major concern in modern design. Traditionally, design tolerances are specified based on the designer’s experience. Computer-aided (or software-based) tolerance synthesis and alternative manufacturing process selection programs allow a designer to verify the relations between all design tolerances to produce a consistent and feasible design. In this paper, a general new methodology using intelligent algorithms viz., Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and Multi Objective Particle Swarm Optimization (MOPSO) for simultaneous optimal selection of design and manufacturing tolerances with alternative manufacturing process selection is presented. The problem has a multi-criterion character in which 3 objective functions, 3 constraints and 5 variables are considered. The average fitness factor method and normalized weighted objective functions method are separately used to select the best optimal solution from Pareto optimal fronts. Two multi-objective performance measures namely solution spread measure and ratio of non-dominated individuals are used to evaluate the strength of Pareto optimal fronts. Two more multi-objective performance measures namely optimiser overhead and algorithm effort are used to find the computational effort of NSGA-II and MOPSO algorithms. The Pareto optimal fronts and results obtained from various techniques are compared and analysed.     

Improved expert selection model for forex trading

Online prediction is a process that repeatedly predicts the next element in the coming period from a sequence of given previous elements. This process has a broad range of applications in various areas, such as medical, streaming media, and finance. The greatest challenge for online prediction is that the sequence data may not have explicit features because the data is frequently updated, which means good predictions are difficult to maintain. One of the popular solutions is to make the prediction with expert advice, and the challenge is to pick the right experts with minimum cumulative loss. In this research, we use the forex trading prediction, which is a good example for online prediction, as a case study. We also propose an improved expert selection model to select a good set of forex experts by learning previously observed sequences. Our model considers not only the average mistakes made by experts, but also the average profit earned by experts, to achieve a better performance, particularly in terms of financial profit. We demonstrate the merits of our model on two real major currency pairs corpora with extensive experiments.     

基于模糊灰关联分析的软件引入决策模型

在模糊环境下提出软件引入的决策模型.该模型是基于移除分辨系数的灰关联分析,案例是评价台湾地区路面管理系统的最佳化优选问题.应用德菲法搜集的案例数据显示了省道和县、乡道主管部门对软件的认知差异和需求偏好.采用理想解趋近法(TOPSIS)比较该模型的强健性.对比结果显示两种方法均建议引入MicroPAVER5.1软件,而所提出模型的适用性比TOPSIS更为广泛.     

Shaping a buyer's software selection process through tendering legislation

Tendering legislation aims to enhance competitiveness by promoting equality, proportionality, transparency, and non‐discrimination. Such legislation applies to the procurement of software packages by public institutions in many countries. This study explores how tendering legislation shapes a buyer's software selection process through the lens of competing decision‐making rationalities. From the literature, 3 rationalities enacted in software selection are deduced that we relate to the software selection literature regarding tendering legislation. Through this lens, we subsequently examine how a large health care provider selected a supplier for an electronic health record system after an extensive tendering process. Many health care professionals within this organization were in favour of a particular software package. Yet, the organization purchased a different package from a relatively unknown supplier, the implementation of which failed. The actors involved experienced shaping on 5 decision‐making themes, the implications of which are evaluated against the functional, economic, and political rationality norms derived from the literature. The findings suggest that compliance with tendering legislation over the public procurement of software results in increased legal complexity, greater linearity and objectivity, more extensive formalization, and less relational communication. Functional norms of rationality are stressed, seemingly to balance the enforced economic norms of rationality and to compensate for the decreased room for political rationality. Even so, the shaping by the tendering legislation threatens functional rationality. Ultimately functional and economic norms of rationality win over political rationality, yet the latter still dribbles through, albeit in a different guise than reported for software selection in general.     

Analysis, design, and development model: a case study of an internet-based system for insert and parameter selection

Abstract. The analysis, design, and development model (ADDM) is based on the systems lifecycle process (SLCP) in which analysts begin to understand external client requirements and internal client specifications as they are designing and developing a complex system. In the ADDM, clients and system analysts (SA) continuously interact as the system is being designed, developed, tested and maintained. In the design phase, system development can be altered when it is most cost‐effective. Depending on the type of environment and SA preference and expertise, various interfaces and software and hardware configurations are created during the SLCP. The SLCP ensures effective standardization and continuous quality improvements throughout development. The model follows modern information technology principles to integrate and monitor SLCP phases. A case is presented that describes an application of the ADDM. This case outlines the architecture of an e‐commerce production system (ECPS). The system has a three‐tier structure consisting of the client interface, Java server page (JSP) and database module. The model assists in designing economic production operations in an industrial setting by allowing a client to retrieve current production data needed for operations through the internet.     

Developing control and integration software for flexible manufacturing systems

The slow growth of computer-integrated manufacturing is attributed to the complexity of designing and implementing their control and integration software. This article expands on a methodology for designing and implementing this software that was introduced in [16]. The goal of this methodology is to build flexible and resuable control and integration software for computer-integrated manufacturing systems. It hinges upon the concepts of software/hardware components, their assemblages, a distributed common language environment, formal models, and generic controllers. Major sources of flexibility are obtained by decoupling process plan models from the model of the factory floor and by using a generic controller. Reusability is achieved by building selfcontained software/hardware components with general, possibly parametrized, interfaces. The interplay between simulated and actual hardware internals of software/hardware components is used as the basis of a testing strategy that performs off-line simulation followed by on-line testing.The methodology has been applied in designing and implementing the control and integration software of an actual Prismatic Machining Cell. The article also reports on the details of this implementation.The names of the authors appear in alphabetical order.     

A non-dominated sorting genetic algorithm based approach for optimal machines selection in reconfigurable manufacturing environment

This paper deals with a problem of reconfigurable manufacturing systems (RMSs) design based on products specifications and reconfigurable machines capabilities. A reconfigurable manufacturing environment includes machines, tools, system layout, etc. Moreover, the machine can be reconfigured to meet the changing needs in terms of capacity and functionality, which means that the same machine can be modified in order to perform different tasks depending on the offered axes of motion in each configuration and the availability of tools. This problem is related to the selection of candidate reconfigurable machines among an available set, which will be then used to carry out a certain product based on the product characteristics. The selection of the machines considers two main objectives respectively the minimization of the total cost (production cost, reconfiguration cost, tool changing cost and tool using cost) and the total completion time. An adapted version of the non- dominated sorting genetic algorithm (NSGA-II) is proposed to solve the problem. To demonstrate the effectiveness of the proposed approach on RMS design problem, a numerical example is presented and the obtained results are discussed with suggested future research.     

用于软件选型的度量模型及系统实现

针对现有软件选型手段存在的缺乏统一标准、主观性和片面性较强的问题,建立了软件选型过程模型,设计了基于模糊综合评价的软件选型度量模型,讨论了软件选型度量模型的三个层次,进而开发了可操作的软件选型度量原型系统,并通过实验验证了该系统的有效性。