Showing papers in "Iie Transactions in 1996"
TL;DR: In this article, the Response Surface Methodology (RSM) is used for scheduling and scheduling in response surface methodologies, and it is shown that it can be used in a variety of scenarios.
Abstract: (1996). Response Surface Methodology. IIE Transactions: Vol. 28, Scheduling and Logistics, pp. 1031-1032.
4,299 citations
TL;DR: Burdea and Coiffet as mentioned in this paper reviewed virtual reality technology and gave a good review of Burdea et al.'s work, including a review of virtual reality games.
Abstract: (1996). A review of: “Virtual Reality Technology” Grigore Burdea and Philippe Coiffet John Wiley & Sons, Inc., 1994. IIE Transactions: Vol. 28, No. 6, pp. 523-524.
175 citations
TL;DR: Geometric feature variations are the result of variations in the shape, orientation or location of part features as defined in the ANSI Y14.5M-1982 tolerance standard as discussed by the authors. When such feature variations occu...
Abstract: Geometric feature variations are the result of variations in the shape, orientation or location of part features as defined in ANSI Y14.5M-1982 tolerance standard. When such feature variations occu...
166 citations
TL;DR: In this article, an integer program that is solved using a GA to assist in the design of cellular manufacturing systems is presented, where a unique representation scheme for individuals (part/machine partitions) is used to reduce the size of the cell formation problem and increase the scale of problems that can be solved.
Abstract: The design of a cellular manufacturing system requires that a part population, at least minimally described by its use of process technology (part/machine incidence matrix), be partitioned into part families and that the associated plant equipment be partitioned into machine cells. At the highest level, the objective is to form a set of completely autonomous units such that inter-cell movement of parts is minimized. We present an integer program that is solved using a genetic algorithm (GA) to assist in the design of cellular manufacturing systems. The formulation uses a unique representation scheme for individuals (part/machine partitions) that reduces the size of the cell formation problem and increases the scale of problems that can be solved. This approach offers improved design flexibility by allowing a variety of evaluation functions to be employed and by incorporating design constraints during cell formation. The effectiveness of the GA approach is demonstrated on several problems from the literature.
144 citations
TL;DR: This paper presents the optimization model to develop the specification region for multiple quality characteristics based on the framework of multivariate quality loss function and suggests a multivariate normal distribution is considered for the quality characteristics.
Abstract: Economic specification limits have typically been developed on the basis of a single quality characteristic. From the viewpoint of the customer, products are often evaluated based on multiple quality characteristics. The specification region for multiple quality characteristics must be determined on an economic basis where we minimize the total loss to both the producer and the customer and thus to the whole society. In this paper a multivariate normal distribution is considered for the quality characteristics. The specification region is given by truncating the multivariate normal distribution. We present the optimization model to develop the specification region for multiple quality characteristics based on the framework of multivariate quality loss function.
126 citations
TL;DR: In this article, the authors consider an assembly problem where two critical components are required for assembly of the final product, the demand for which is stochastic and the supplier delivery process may be random owing to uncertainty in the production process (e.g., semiconductor industries).
Abstract: In this paper we consider an assembly problem where two critical components are required for assembly of the final product, the demand for which is stochastic. The components can be ordered separately from individual suppliers or in a set (a set refers to the components in the required ratio) from a joint supplier. We consider the case where the assembly stage is free, i.e., the firm procures and stores the components and sells complete sets. The supplier delivery process may be random owing to uncertainty in the production process (e.g., semiconductor industries). We assume that a supplier, with probability β (say), supplies 100% of the order quantity in the current period, and with probability (1 - β) supplies nothing. If there is no delivery during this period, the order is delivered in the next period. The added complexity of coordinating shipments of different components requires careful planning in placing the orders. In the single-period problem, if no order is placed with the joint supplier, the order quantities from the individual suppliers follows an order-up-to policy structure with identical order levels. However, it is optimal to diversify (i.e., order from the joint supplier as well) when the inventory level is below a certain threshold (determined in this paper). With lower initial inventory levels, the firm cannot risk the cost of stockouts if the individual supplier(s) fail to deliver in the current period. With certain conditions on the cost and delivery parameters of the suppliers, we show that the policy structure for the multi-period problem is similar to that of the single-period problem, except that the order up-to-levels are not the same. Intuitively, it might be optimal to order extra components for use in the future. This is a direct consequence of the uncertainty in the delivery timing of the suppliers. Finally we conduct a computational study of the two-period problem and determine the effect of supplier costs and the probability of delivery on the optimal order policy. The policies are intuitive and offer a better understanding of the effect of supply and demand uncertainty on the assembly problem.
111 citations
TL;DR: In this paper, a preventive maintenance policy was proposed to enhance the reliability of a deteriorating production system and derive an optimal preventive policy for the Weibull and extreme-value distributions.
Abstract: The traditional Economic Manufacturing Quantity (EMQ) model assumes that the production process (system) is perfect. However, owing to aging, the production process will shift from the ‘in-control’ state to the ‘out-of-control’ state and produce defective items. When the process shift distribution follows an Increasing Failure Rate (IFR) distribution, preventive (scheduled) maintenance policy is usually used to enhance its reliability. In this paper we incorporate a preventive maintenance policy into this deteriorating production system and derive an optimal preventive maintenance policy. Two well-known IFR distributions, Weibull and extreme-value distributions, are considered and some examples are used to illustrate the proposed model. Finally, the advantages of the proposed model are addressed in the conclusion.
105 citations
TL;DR: In this paper, the effects of increasing component commonality for a single-period model with a two-product, two-level configuration under a general component cost structure is considered.
Abstract: In this paper we study the effects of increasing component commonality for a single-period model. A two-product, two-level configuration under a general component cost structure is considered. The economic implications of replacing different products' components by common components are analyzed. We develop optimal solutions for the Commonality and Non-Commonality (Basic) Models and provide bounds on the total savings resulting from using commonality. We demonstrate, under general and specific component cost structures, that some forms of commonality may not always be a preferred strategy. Furthermore, we present conditions under which commonality should not be used. Finally, an extension to the two-product multicomponent model is provided.
102 citations
TL;DR: It is shown that the age replacement and ordering decisions for a system with only one component subject to random failure and with room for only one spare in stock has some convexity properties that make it amenable to minimization.
Abstract: We examine age replacement and ordering decisions for a system with only one component subject to random failure and with room for only one spare in stock. The system incurs costs for replacement, shortage, holding, and breakage; the lead time for receipt of an ordered spare is constant. We consider the solvability and desirability of jointly optimizing these two traditionally separate decisions. We show that the problem has some convexity properties that make it amenable to minimization. For our data set, we find that using separate optimization gives an average loss of 3% relative to the joint minimum; about a tenth of die time the difference was more than 10%, but in general this loss can vary from zero to arbitrarily large.
102 citations
TL;DR: In this paper, a variable-sampling-interval (VSI) control chart with fixed times (VSIFT) is proposed, in which samples are always taken at specified equally spaced fixed time points, but additional samples are allowed between these fixed times when indicated by the data from the process.
Abstract: When control charts are used for process monitoring, the traditional practice is to take samples from the process by using a fixed sampling interval (FSI) between samples. Recently developed variable-sampling-interval (VSI) charts vary the sampling interval as a function of the process data to give faster detection of process changes. This paper considers a type of VSI control chart in which samples are always taken at specified equally spaced fixed time points, but additional samples are allowed between these fixed times when indicated by the data from the process. The location of the fixed times would typically be determined by administrative considerations such as testing schedules or by the desirability of sampling according to natural periods in the process. Markov process methods are given for analyzing the performance of these VSI with fixed times (VSIFT) charts. The VSIFT feature is considered for the X¯-chart, the EWMA chart and the CUSUM chart. It is shown that VSIFT charts will detect most proc...
101 citations
TL;DR: In this article, a rating scheme is described that allows the designer to translate form properties of a design into quantitative scores, and thus provides a means of identifying weaknesses in the design and comparing alternatives.
Abstract: Quantitative measures and a procedure for evaluating the ease of disassembly of products when recycling them are presented. A rating scheme is described that allows the designer to translate form properties of a design into quantitative scores, and thus provides a means of identifying weaknesses in the design and comparing alternatives. As part of a broader effort in design for disassembly and recycling, the current work emphasizes the provision of feedback to the designer. The discussion focuses around robotic disassembly for recycling of small electrical appliances; however, the same methodology applies to manual dismantling and other products.
TL;DR: In this paper, a U-shaped manufacturing module with fewer workers than machines is modeled and a definition of the module's rules of movement is presented, where workers move in order around the layout.
Abstract: We model a U-shaped manufacturing module that operates with fewer workers than machines. Workers move in order around the layout. A definition of the module’s rules of movement are presented. The t...
TL;DR: It is proved that all the expected profit functions are concave (jointly concave), and decelerated demand for lower-grade products can be met, if necessary, by higher-grade units.
Abstract: Production systems with random functionality yields and downward substitutable demand are modeled and investigated. Such systems arise frequently in the electronics and petrochemical industries. We analyze two single-period models. The first models a single production process in which the total yield of usable products is uncertain; furthermore the realized usable products are of two grades, higher and lower, and the portions of each grade products are also uncertain. Demand for lower-grade products can be met, if necessary, by higher-grade units. The second model we analyze has two parallel production processes: one is as in die previous model; the other is attempting to produce lower-grade products only, but their yield is random. In both single-process and two-process scenarios the relative magnitudes of the salvage values of the two product grades lead to somewhat different models that need to be analyzed separately. We prove that all the expected profit functions are concave (jointly concave), and de...
TL;DR: In this paper, the authors used Data Envelopment Analysis (DEA) to measure multiple performance criteria for 42 dispatching rules in a job shop environment and evaluated the efficiency of each dispatching rule relative to the other rules.
Abstract: This paper uses Data Envelopment Analysis (DEA) to measure multiple performance criteria for 42 dispatching rules in a job shop environment. We introduce a DEA application in production scheduling. Seven performance measures are considered in the evaluation. Without pre-assigning weights to any performance measure, DEA evaluates the efficiency of each dispatching rule relative to the other rules. After running a large number of experiments, the results show that two extreme subgroups of dispatching rules perform consistently. The shortest processing time related rules form the top group, while the longest processing time related rules form the bottom group. The due date or slack-related rules perform well in tardiness. However, they are ranked low if all seven criteria are considered together. The results provide guidance to scheduling practitioners in choosing priority dispatching rules when there are multiple objectives.
TL;DR: In this article, the authors discuss various aspects of parallel machining that influence the generation of process plans, and describe a process planner that uses a genetic algorithm for sequencing operations, which is more complicated than their sequential counterparts.
Abstract: Parallel numerically controlled machines can perform multiple machining operations simultaneously using combinations of interacting workholding and tool holding devices. One type of parallel machine, the Mill/Turn, also has the ability to perform both turning and milling operations in the same setup. These machines, in addition to being suitable for large volume machining, also have the potential for efficiently producing small batch sizes. Consequently, Mill/Turns can be used as a rapid prototyping tool. One of the major hurdles to integrating Mill/Turns into manufacturing environments is the absence of computer-aided processing planning systems. This problem is more acute in the parallel-machining domain because process plans for parallel machining are more complicated than their sequential counterparts. In this paper we discuss various aspects of parallel machining that influence the generation of process plans, and describe a process planner that uses a genetic algorithm for sequencing operations. Imp...
TL;DR: In this paper, a structured procedure for order pick system analysis and design has been established on literature review and interviews with and presentations to OPS experts, including the thinking processes that occur between OPS designers and owners.
Abstract: We present a structured procedure for order pick system (OPS) analysis and design that has been established on literature review and interviews with and presentations to OPS experts. In particular, we attempt to include the thinking processes that occur between OPS designers and owners. The design procedure and related issues are discussed in the order of input, selection, and evaluation stages.
TL;DR: In this article, the authors investigate automated storage/retrieval systems where a due date is specified for each retrieval order and consider the inclusion of both order retrieval and storage in the same tour when possible.
Abstract: In this paper we investigate automated storage/retrieval systems where a due date is specified for each retrieval order. We consider the inclusion of both order retrieval and storage in the same tour when possible. Rules are developed for sequencing and batching orders to tours such that the total tardiness of retrievals per group of orders is minimized.
TL;DR: In this paper, an analytical design algorithm is presented to determine the near-minimum number of pickers required in an end-of-aisle order-picking operation based on a miniload automated storage/retrieval system.
Abstract: In this paper we present an analytical design algorithm to determine the near-minimum number of pickers required in an end-of-aisle order-picking operation based on a miniload automated storage/retrieval system. The algorithm is based on an approximate analytical model we developed to estimate the expected picker utilization (and the storage/retrieval machine utilization) for general system configurations with two or more pick positions per aisle and/or two or more aisles per picker. For systems with two pick positions, we also investigate the possibility of improving the picker utilization by sequencing container retrievals within each order.
TL;DR: In this paper, the authors propose an analytical method for the performance evaluation of closed-loop production lines with unreliable machines and finite buffers, where failure and repair times are exponentially distributed.
Abstract: The purpose of this paper is to propose an analytical method for the performance evaluation of closed-loop production lines with unreliable machines and finite buffers. Such a system consists of a set of K machines separated by buffers of finite capacity. There is a fixed number of pallets circulating in the closed loop. We assume that machines have deterministic processing times but are subject to failures. Failures and repair times are exponentially distributed. We approximate the behavior of this system by a continuous flow model. The continuous flow model is then analyzed with a decomposition technique, which is similar to that used for (open) production lines. Numerical experiments are reported that show that the results provided by this method are in general fairly accurate.
TL;DR: In this article, a robust tabu search approach to the traveling-salesman problem with time windows is presented, which uses a two-level tour hashing scheme within a reactive tabu-search procedure.
Abstract: This paper presents a robust tabu search approach to the traveling-salesman problem with time windows. The approach uses a two-level tour hashing scheme within a reactive tabu search procedure to d...
TL;DR: This analysis shows that a bottleneck station draws buffers toward it, but the optimal allocation depends on the location and severity of the bottleneck, as well as the number of buffers available.
Abstract: The optimal placement of a predetermined amount of buffer capacity in balanced serial production lines is a well-understood problem: in lines with moderate variability, the optimal allocation involves equal numbers of buffers at each site; in lines with severe variability, the equal allocation is modified slightly to place more buffers toward the center of the line. Buffering unbalanced lines is a much less well-understood problem. We study the problem of buffering serial lines with moderate variability and a single bottleneck; i.e., a single station with a larger mean processing time than all other stations. Our analysis shows that a bottleneck station draws buffers toward it, but the optimal allocation depends on the location and severity of the bottleneck, as well as the number of buffers available. Furthermore, relatively large imbalances in mean processing times are required to shift the optimal buffer allocation away from an equal allocation. Finally, line length appears to have a relatively small e...
TL;DR: This work considers a production facility that produces items for which demand occurs according to a Poisson process, and assumes the facility is assumed to deteriorate while it is in operation, with an increasing likelihood of deterioration.
Abstract: We consider a production facility that produces items for which demand occurs according to a Poisson process. The facility is assumed to deteriorate while it is in operation, with an increasing fai...
TL;DR: A graphical, interactive technique for modeling univariate simulation input processes by using a family of probability distributions based on Bezier curves that has an open-ended parameterization and is capable of accurately representing an unlimited variety of distributional shapes.
Abstract: We describe a graphical, interactive technique for modeling univariate simulation input processes by using a family of probability distributions based on Bezier curves. This family has an open-ende...
TL;DR: When production yields are random and orders need to be satisfied in full, several successive production runs may be initiated until an order is met as discussed by the authors, and this multiple lot-sizing problem is known as multiple lot sizing.
Abstract: When production yields are random and orders need to be satisfied in full, several successive production runs may need to be initiated until an order is met. Variants of this multiple lot-sizing pr...
TL;DR: Using results for the AR(1) process, it is shown that generally better performance can be achieved with no skipping and much larger batch sizes.
Abstract: Modern statistical process control must often cope with large quantities of highly autocorrelated data. Alwan and Radson (1992) proposed the monitoring of autocorrelated processes by plotting the averages of small batches of data separated by skipping observations. Using results for the AR(1) process, we show that generally better performance can be achieved with no skipping and much larger batch sizes. The resulting batch-means charts derive from methods used in simulation output analysis and can be implemented easily with common digital control systems.
TL;DR: In this paper, a new model for the optimal design of X¯ charts utilized for the statistical monitoring of processes where production runs have a finite duration is presented, which considers the effect of the setup operation on the chart design.
Abstract: A new model is presented for the optimal design of X¯ charts utilized for the statistical monitoring of processes where production runs have a finite duration. The proposed model considers the effect of the setup operation on the chart design. The model contains both Duncan's model and a model due to Ladany as particular cases, yet it allows the user to consider more realistic production environments. Two types of finite-length production process are considered: a repetitive manufacturing process and a job-shop process. New relationships between the length of the production run, the power of the chart and the nature of the process setup are found by numerically analyzing the behavior of the model.
TL;DR: In this paper, a mixed-integer nonlinear programming problem is formulated to minimize long run inventory holding and order costs per unit of time, and a new algorithm to generate order frequencies, called the powers-of-two-factorof-three technique, is described.
Abstract: The Warehouse Scheduling Problem is a deterministic multi-item inventory problem with a restriction on warehouse floor space available. We formulate a mixed integer nonlinear programming problem for the objective of minimizing long run inventory holding and order costs per unit of time. We integrate algorithms for staggering orders, described in companion papers, with a heuristic to choose the order sequences. The result is called Sequenced Staggering. We describe a new algorithm to generate order frequencies, called the powers-of-two-factor-of-three technique, as a generalization of Roundy's roundoff technique for powers-of-two policies. We report on a computational study of four hybrid algorithms for solving the warehouse scheduling problem, including the competing algorithm of Gallego, Queyranne, and Simchi-Levi. Based on these results, we recommend the combination of powers-of-two frequencies with Sequenced Staggering.
TL;DR: In a dynamic environment, such as high-technology industry, a forward picking area requires an intelligent approach to ongoing rewarehousing (reassignment of stock items to locations) as discussed by the authors.
Abstract: In a dynamic environment, such as high-technology industry, a forward picking area requires an intelligent approach to ongoing rewarehousing (reassignment of stock items to locations). The items go...
TL;DR: A problem of scheduling nindependent and simultaneously available jobs on munrelated parallel machines is considered, which can be solved inO (n3m + n2m log(nm)time), to minimize the total compression cost plus the total flow time.
Abstract: We consider a problem of scheduling nindependent and simultaneously available jobs on munrelated parallel machines. The job processing times can be compressed through incurring an additional cost, which is a convex function of the amount of compression. Two problems are formulated as assignment problems, which can be solved inO (n3m + n2m log(nm))time. One is to minimize the total compression cost plus the total flow time. The other is to minimize the total compression cost plus the sum of earliness and tardiness costs.
TL;DR: In this paper, an exact algorithm for the multi-period facility location problem is proposed that efficiently integrates mixed-integer and dynamic programming methods to reduce the size of the general facility location problems substantially.
Abstract: An exact algorithm for the multi-period facility location problem is proposed that efficiently integrates mixed-integer and dynamic programming methods. Two simplification procedures are introduced to reduce the size of the general multi-period facility location problem substantially. Because the proposed algorithm utilizes dynamic programming to obtain the optimal sequence over the entire planning horizon, many near-optimal solutions also become available that are extremely useful for postoptimality analysis. The solution method is tested and compared with a well-known procedure on several problems with varying conditions. The comparisons appear very promising, and the required CPU times by the proposed method are substantially reduced.