摘要:

Vinod and Solberg (1985) address an optimization problem within the framework of a closed queueing network model for a Flexible Manufacturing System (FMS). The above problem is referred to as the Optimal System Configuration Problem of an FMS. The optimization parameters in the problem are the number of machines at each workstation and the total number of jobs circulating in the system. In this paper we suggest a more efficient algorithm for the solution of the above-mentioned problem. Our algorithm is of an implicit enumeration nature and derives its efficiency from the exploitation of properties of the throughput function of a closed queueing network. The efficiency of the algorithm is demonstrated with the use of extensive computational results.

ISSN:0740-817X    

DOI:10.1080/07408179508936712

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this article we present an algorithm to transform a set(s) of Boolean equations into a Petri net(s). Boolean logic provides a mathematical basis for switching control and many other areas. In the case of programmable logic controllers used for the sequential control in manufacturing applications, Boolean equations are fundamental both in programming and in understanding their operation. A major difficulty with Boolean equations is the lack of any type of mathematical theory for the analysis of the systems that are being represented by these equations. Petri nets, on the other hand, possess a mathematical framework to analyze the properties of the system being modeled. Furthermore, Petri nets have been proved to be appropriate models for sequential control. The popularity as well as the generality of Boolean logic, on one hand, and the modeling and analytical capabilities of Petri nets, on the other hand, are the major motivations for this research.

ISSN:0740-817X    

DOI:10.1080/07408179508936713

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Selecting the assembly sequence and associated automatic assembly stations necessary to assemble a candidate product design is a critical step in the life cycle of a product. We present a method that determines the best sequence and set of stations using cost and performance measures. The method uses a multi-echelon optimization procedure based on simulated annealing. We show how simulated annealing can be used for such problems and present examples in which we determine the optimal assembly sequence for a product in an automated manufacturing environment.

ISSN:0740-817X    

DOI:10.1080/07408179508936714

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper develops a discrete-event hybrid simulation/analytic model for the study of production networks. The system is represented by a set of nonlinear difference equations for the slow-varying dynamics, which are tractable by simulation, and a set of piecewise linear algebraic equations for the fast dynamics, which are solved analytically. The resulting algorithm saves a great amount of computation and is much faster than conventional piece-by-piece simulators.

ISSN:0740-817X    

DOI:10.1080/07408179508936715

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Clustering a machine-part matrix is the first step in the design of a cellular manufacturing system. It provides a basis for matching the machine groups to the part families that they must produce. The problem of clustering a machine-part matrix can be decomposed into two problems: designing a measure for clustering efficiency (CE) and searching for a permutation of rows and columns of the matrix to maximize this measure. Clustering is done by permuting the rows and columns of the initial machine-part matrix to produce a block diagonal form (BDF). The clustering efficiency of a machine-part matrix measures the desirability of its BDF as a solution to cell design. This paper evaluates six measures of CE and six search methods. Extensive experiments were carried out to find the combination of CE measure and search method that produces the best solution in reasonable CPU time. We used several benchmark machine-part matrices from the literature and several problems obtained from a local manufacturer. We performed a multivariate analysis of variance (MANOVA) to compare the search algorithms and the CE measures.

ISSN:0740-817X    

DOI:10.1080/07408179508936716

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The purpose of this paper is to view recent developments in non-von Neumann and Morgenstern utility functions (vNM) via a stationary statistical-economic model. Such a model is suggested in the literature for evaluating robot precision, assuming that repeatability follows a Rayleigh distribution. Various vNM and non-vNM utility forms are discussed and illustrated for the robot evaluation and selection problem. The approach suggested here may be applicable for companies operating under profit centers where market systematic risk data are not available and decisions are based on the decision maker's (DM) attitude toward risk. Although the numerical illustrations demonstrate a consistency among the expected profit measure for most utility forms that were investigated, the analysis provides an extended framework for dealing with risky production problems. Furthermore, it illustrates the sensitivity of robot operational decisions such as speed and of both the output rate per time unit and the product quality to the DM's attitude toward risk. It allows the DM to analyze and explain decisions as affected by the selection of the utility form, as well as the technological and economic parameters and measures describing the problem, particularly the technical risk involved in the determination of a robot operational problem.

ISSN:0740-817X    

DOI:10.1080/07408179508936717

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Design for assembly (DFA) involves the consideration of the assembly process while designing. It is important in that it is at the design stage that significant decisions about the assembly process are made. This paper overviews the background to DFA and presents an approach to DFA that operates by analyzing a design using constraint networks. This approach gives advice to the designer on changes that should be made to improve the design. The designer can interact with the constraint network system to make gradual improvements. The approach has been implemented as a prototype using the constraint language SPARK. The use of constraint networks for DFA has a number of advantages over more conventional techniques: advice is given on how to improve the design, the designer can interact with the DFA system to improve the design, and the designer can approach the problem from any viewpoint in that a rigid procedure does not have to be followed. The result is a flexible DFA system that can be adapted relatively easily to a particular environment.

ISSN:0740-817X    

DOI:10.1080/07408179508936718

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper we discuss a functional testing problem in the printed circuit card assembly environment. The testing problem the design engineer faces is the following: Assign the maximum number of 100 mil (1 mil = 10−3inch) probes to an appropriately selected set of 50 mil pads in a way that avoids the creation of short circuits or other imposed engineering constraints. Once the above assignment problem is solved, a testing fixture that holds the 100 mil probes at their appropriate positions is constructed. We are addressing the design problem of the above mentioned testing fixture. An integer programming formulation of the problem is presented. A hierarchical decomposition scheme, which at a first level specifies the subset of 50 mil pads to be tested, and at a second level decides on the allocation of a 100 or 50 mil probes to the tested pads, exhibits a near optimal performance for most cases of practical interest. The first-level problem can be solved in polynomial time with a greedy procedure. The second-level problem is equivalent to node packing. For a special class of sparse graphs encountered in our application a simple greedy algorithm optimally solves the corresponding node packing problem.

ISSN:0740-817X    

DOI:10.1080/07408179508936719

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Process planning output can be post-processed into criteria for job scheduling decisions in printed circuit board assembly using surface-mount technology (SMT). Artificial intelligence-based techniques used in computerized planning and scheduling systems in other industries can be extended to printed circuit board operations. These techniques include blackboard architectures, object-oriented programming systems, and nonmonotonic reasoning systems. These techniques were used to demonstrate a unique architecture of blackboard systems that communicate via object-oriented messages to arrive at a shop-floor process plan and production schedule. The methodology was specialized to the assembly of printed circuit boards using surface-mounted components in a high-variety/low-volume product mix. The assembly facility was represented as a hierarchical object of product, process, and organizational knowledge. The system of working heuristics was integrated within a prototype environment with the practitioners that assisted in its development. The end result is a good working methodology for system development, implementation, and maintenance by knowledge worker involvement.

ISSN:0740-817X    

DOI:10.1080/07408179508936720

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In many automated manufacturing environments, particularly flowlines and flexible manufacturing systems (FMSs), machines are arranged along a straight material-handling track with a material-handling device moving jobs from one machine to another. These layouts are referred to as row machine layouts. In this paper we study the row layout problem (RLP) under the design objective of minimizing the total backtracking distance of the material-handling device, which is an NP-complete problem. We propose the use of a dynamic programming algorithm for its solution. A special case of the problem, usually encountered in flexible manufacturing cells and which can be solved with a polynomial procedure, is also discussed. For the equidistance case (i.e., successive candidate locations are in equal distances), we formulate the problem as an integer linear program. The use of standard mathematical programming codes can efficiently solve this formulation.

ISSN:0740-817X    

DOI:10.1080/07408179508936721

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor