Showing papers in "Iie Transactions in 1975"
TL;DR: In this paper, the layout problem is formulated as a quadratic set covering problem, and a branch and bound method for optimizing the resulting problem is devised, which can be provided to the layout engineer for consideration and modification.
Abstract: This paper presents a computerized procedure for layout design. The layout problem is formulated as a quadratic set covering problem. A branch and bound method for optimizing the resulting problem is devised. As a result, optimal and suboptimal layouts can be provided to the layout engineer for consideration and modification.
170 citations
TL;DR: A computer based three dimensional strength model was used to predict hand forces at 38 different positions for a seated operator, and the hip height predictions proved more accurate than the shoulder height predictions.
Abstract: A computer based three dimensional strength model was used to predict hand forces at 38 different positions for a seated operator. These predictions were compared with the forces exerted by 71 male subjects. Error coefficients of variation averaged from 0.27 to 0.49, and correlation coefficients between the measured and predicted hand forces averaged from 0.93 to 0.97. The hip height predictions proved more accurate than the shoulder height predictions.
123 citations
IBM1
TL;DR: In this paper, a new algorithm was developed to calculate economic lot sizes for manufactured products, which allows for fluctuating and uncertain demand patterns which limit the effectiveness of the classical Wilson EOQ formula.
Abstract: A new algorithm has been developed to calculate economic lot sizes for manufactured products. The algorithm allows for fluctuating and uncertain demand patterns which limit the effectiveness of the classical Wilson EOQ formula. In an environment of uncertain future demand, its performance is on a par with the Wagner-Whitin technique. Yet, the computations required are considerably less. For a single product the algorithm would produce results identical to the Part/Period formula of IBM. However, a new derivation is provided which parallels the derivation of the Silver and Meal formula. A new dimension is added when the algorithm is extended to the situation where there are limits on the combined production rate of all products. The algorithm prevents production from exceeding the limit. It therefore allows lot sizing to be implemented gradually, and it continues to protect the production line against sudden increases in demand after implementation. Finally, the dynamic lot sizing algorithm with c...
106 citations
TL;DR: Some summary measures which might be used in specifying the size, shape, logic, time and resource characteristics of project networks of the PERT/CPM type are described and procedures for estimating project duration increase in advance of scheduling are described.
Abstract: This paper describes some summary measures which might be used in specifying the size, shape, logic, time and resource characteristics of project networks of the PERT/CPM type. The results of an investigation to determine relationships between some selected such measures and project duration increase under constrained-resource scheduling are presented, and procedures for estimating project duration increase in advance of scheduling are described.
91 citations
TL;DR: In this article, the authors reviewed five approaches to the smoothing problem: HMMS linear decision rule, DE rule, management coefficients method, use of LP models, production switching method, and management coefficient method.
Abstract: Production scheduling problems are reviewed briefly and the smoothing problem is defined as planning the aggregate production level for each period in a given horizon to meet forecast demand. Five approaches to the problem are reviewed: (1) the HMMS linear decision rule for production and employment; (2) the DE rule for production, in which time lag is incorporated; (3) the management coefficients method; (4) the use of LP models; (5) the production switching method. The assumptions and objectives inherent in each approach are discussed and certain shortcomings are indicated.
76 citations
TL;DR: In this article, the authors present an analytical study of two-stage production systems with variable operation times and provision for intermediate storage. And they show that for moderate coefficients of variation the production rates for these two distributions differ only marginally.
Abstract: This paper presents an analytical study of several aspects of two-stage production systems with variable operation times and provision for intermediate storage. For the exponential service times assumed at one of the stages, the set of simultaneous equations satisfied by the steady-state probabilities are shown to involve the Laplace transform of the density function at the other stage and its various order derivatives. An analysis of this set of equations leads to a recursive solution for the mean production rate of a system with any number of storages. The realistic cases of Erlang and normal density functions are worked out in detail. It turns out that for moderate coefficients of variation the production rates for these two distributions differ only marginally. That this is not generally true is illustrated by considering a uniform distribution, for which the results are significantly different. The problem of balancing the production system is discussed at some length. It is shown that the p...
71 citations
TL;DR: In this paper, an efficient branch and bound algorithm and near optimal heuristic algorithms for solving the problem of withdrawing inventory and/or service facilities for a good or service whose overall demand is declining over time are presented.
Abstract: This paper presents an efficient branch and bound algorithm and near optimal heuristic algorithms for solving the problem of withdrawing inventory and/or service facilities for a good or service whose overall demand is declining over time. In particular, this paper models the problem faced by a manager who must consider closing up to M initially open and operating support facilities as demand shifts and declines over a T period planning horizon. The criterion is minimization of total estimated discounted costs. The costs considered are the variable operating cost at each facility, the transportation costs between facilities and demand centers, and the costs to operate and close each facility. Computational results are presented for both the optimum finding and heuristic algorithms.
69 citations
TL;DR: A comparative study is made between three methods for balancing single-model assembly lines, 10-SP, which selects the best of ten single-pass solutions; ARCUS—a random multi-pass method, and MALB, an iterative backtracking method.
Abstract: A comparative study is made between three methods for balancing single-model assembly lines. These include: 10-SP, which selects the best of ten single-pass solutions; ARCUS—a random multi-pass method, and MALB, an iterative backtracking method. The assembly tasks contain up to 140 work elements with widely differing precedence structures. Measurements of the Balance Delay are used for comparing the solution efficiencies and computation times are also compared. The experiments show significant differences between the three line balancing methods and that these differences are accentuated for certain conditions of task size, precedence structure and the imposed balancing requirements. It is shown that 10-SP is yet another simple but effective technique for balancing single-model assembly lines.
60 citations
TL;DR: The state-of-the-art of deterministic networks is surveyed with a discussion of shortest path, transportation, assignment, transshipment, maximum flow, minimum spanning tree, Chinese postman, Euler path and multicommodity flow models.
Abstract: The state-of-the-art of deterministic networks is surveyed with a discussion of shortest path, transportation, assignment, transshipment, maximum flow, minimum spanning tree, Chinese postman, Euler path and multicommodity flow models. The computational complexity of network models is discussed. The survey concentrates on models and algorithms that can be used to solve large-scale problems.
41 citations
TL;DR: Topics discussed are: random variate generation, programming languages, starting conditions, sample size, variance reduction, design of experiments and validation, and areas needing additional research.
Abstract: Simulation is one of the most powerful analysis tools available to those responsible for the design and/or operation of complex processes or systems. It is heavily based upon computer science, mathematics, probability theory and statistics; yet the process of simulation modeling and experimentation remains very much an intuitive art. This paper attempts to survey selected aspects and point out areas needing additional research. Among the topics discussed are: random variate generation, programming languages, starting conditions, sample size, variance reduction, design of experiments and validation.
40 citations
TL;DR: In this article, the authors deal with the problem of evaluating the effect of a surge on the availability of a series production system (line), a problem of interest to many industrial engineers.
Abstract: This paper deals with the problem of evaluating the effect of a surge on the availability of a series production system (line), a problem of interest to many industrial engineers. Recursive equations are developed to estimate the expected surge protection prior to equipment failure. This expected surge protection can be used to obtain equivalent component lifetimes (time between failures) and repair times, and thus evaluate the effect of surge on the system. The recursive equations for the case of exponentially distributed lifetimes and Erlang distributed repair times are presented and employed in a numerical example.
TL;DR: Basic properties of queueing networks are introduced by their queue length vector processes as being Markov processes or not and some points in need of further research are established.
Abstract: This paper introduces basic properties of queueing networks. Networks are classified by their queue length vector processes as being Markov processes or not. In each case the relevant problems are exposed and the literature of each problem is surveyed. The paper concludes with a discussion of the results, and some points in need of further research are established.
TL;DR: An extended stochastic network simulation model and program, GERTS QR, is utilized to model and analyze “job-shop” systems where both machines and labor are limiting resources.
Abstract: This paper presents an application of a new model for analysis of a special class of multi resource constrained queueing systems. The systems are “job-shop” systems where both machines and labor are limiting resources. The job-shop model has M parallel channels consisting of a work center containing a single machine at which a single processing operation is performed. Each channel has its own queue in which a strict FCFS discipline is enforced; items are not allowed to switch queues or balk. Arrivals to the system are Poisson and are assigned to a specific service channel at arrival time. The labor force consists of N laborers where N < M; it is assumed that all laborers are equally skilled on a given machine (work center). When jobs compete for labor, the labor is assigned on a first-in-first-out basis. An extended stochastic network simulation model and program, GERTS QR, is utilized to model and analyze the systems.
TL;DR: In this paper, the authors considered a production process monitored by the General Control Chart with Warning Limits, where a single assignable cause is assumed to randomly occur which shifts the distribution of the attribute values of parts produced to known values, and an expression for the average cost per good part produced is developed.
Abstract: The paper considers a production process monitored by the General Control Chart With Warning Limits. A single assignable cause is assumed to randomly occur which shifts the distribution of the attribute values of parts produced to known values. The costs of inspection, defective production, and searching for and connecting assignable causes are considered, and an expression for the average cost per good part produced is developed. Markov modeling is used to determine various probabilities and expected values which comprise the average cost expression. A numerical example is presented which indicates the variation in the average cost expression and optimization considerations are presented.
TL;DR: In this paper, a method is developed for determining economical acceptance sampling plans where the characteristics of interest are a mixture of variables and attributes, and an optimum plan is found by minimizing the expected cost model with respect to the decision variables which are the sample size and control limits on the sample means for variables and the sample sizes and acceptance numbers for attributes.
Abstract: A method is developed for determining economical acceptance sampling plans where the characteristics of interest are a mixture of variables and attributes. The method uses a model which has been developed to represent the total expected cost per lot of exercising acceptance sampling. An optimum plan is found by minimizing the expected cost model with respect to the decision variables which are the sample sizes and control limits on the sample means for variables and the sample sizes and acceptance numbers for attributes. Optimization is accomplished using the pattern search.
TL;DR: A new GERTS model and simulator is presented directed to the modeling and analysis of Multi-Resource Constrained (MRC) queueing systems, systems where resource requirements, in addition to the availability of a service center or channel, may constrain the system.
Abstract: This paper presents a new GERTS model and simulator, GERTS QR, directed to the modeling and analysis of Multi-Resource Constrained (MRC) queueing systems. That is, systems where resource requirements, in addition to the availability of a service center or channel, may constrain the system. The development and notation of the GERTS QR model are briefly summarized, and three examples of MRC queueing systems are given to illustrate the application of the model. The three examples are: (1) a labor-limited job shop queueing system, (2) a retail sales outlet, and (3) the planning of a jet engine overhaul facility.
TL;DR: In this paper, Seppala's "Chance-Constrained Programming Algorithm" is used to solve the stochastic multi-facility location problems, where transportation costs are random variables and distances between facilities are Euclidean.
Abstract: This paper first discusses randomness in industrial multi-facility location problems. Different kinds of optimization criteria are then described for a stochastic location problem and the fractile approach is chosen. Seppala's “Chance-Constrained Programming Algorithm” is used to solve the stochastic multi-facility location problems, where transportation costs are random variables and distances between facilities are Euclidean. The covariance matrix of the problem is defined by weighting two extreme cases, where in one case the random cost variables are totally correlated and in another case they are distributed independently of one another. Finally a numerical example is presented and solved. The solutions of deterministic and stochastic versions of multi-facility problems differ greatly from one another.
TL;DR: In this article, a laboratory study of work under a stereo microscope revealed no differences in performance time due to magnification levels of 3.5, 9.25, and 15X.
Abstract: With the trend toward micro-miniaturization in the electronics industry, the development of predetermined time standards for microscopic work has become an important area in work measurement. In conjunction with the development of the MTM-Magnification system, a laboratory study of work under a stereo microscope revealed no differences in performance time due to magnification levels of 3.5, 9.25, and 15X. The simulated task was broken down into elements of reach plus grasp, move plus position, decision, and tap target, and the average time for each element could be accurately predicted using predictors such as Fitts' Index of Difficulty (ID). For example, reach plus grasp time (ms) = 292 + 150 ID - 40 IPC, r 2 = .92, SE = 58.2 ms, where the IPC is a predictor developed in this research.
TL;DR: A practical procedure for applying existing theory to obtain “approximate optimum” replacement policies for homogeneous pieces of equipment and the problem of detecting changes in time-to-failure distributions is described.
Abstract: This paper describes a practical procedure for applying existing theory to obtain “approximate optimum” replacement policies for homogeneous pieces of equipment. In addition, the problem of detecting changes in time-to-failure distributions, the relation of these distributions to the life cycles of equipment, and common mistakes that can result in improper policies are discussed. Application of the procedure is illustrated by two examples encountered by Union Carbide Corporation—Nuclear Division personnel.
TL;DR: In this article, an equivalence relationship between the penalty cost and disservice level that is useful for inventory management is derived using an approximation for the special case of normal lead time demand.
Abstract: An equivalence relationship between the penalty cost and disservice level that is useful for inventory management is the theme of this paper. Using an approximation this relationship is derived for the special case of normal lead time demand. In addition, approximate but explicit formulas for the optimal order size and reorder point are obtained and tables provided so as to reduce the actual computational effort to elementary operations.
TL;DR: The current status of general purpose linear programming algorithms is presented and the following topics are discussed: Simplex Methods Primal-Dual Methods Generalized Inverse Applications Other Approaches Commercial Computer Codes.
Abstract: The purpose of this paper is to present the current status of general purpose linear programming algorithms. After a mathematical statement of the general linear programming problem, the following topics are discussed: Simplex Methods Primal-Dual Methods Generalized Inverse Applications Other Approaches Commercial Computer Codes Several possible areas for future research are indicated both in the body of the paper and in the concluding section.
TL;DR: In this paper, a modified multiple traveling salesmen cost matrix is used to model the routing of solid waste collection vehicles and two examples demonstrate the real world applicability of the procedure and the need for more efficient solution techniques.
Abstract: This note employs a modified multiple traveling salesmen cost matrix to model the routing of solid waste collection vehicles. Two examples are presented to demonstrate the real world applicability of the procedure and the need for more efficient solution techniques. In the first example, a facilities location technique is used in conjunction with the routing model to locate a transfer station.
TL;DR: An extensive example problem is presented in which the two modeling approaches are compared using sensitivity measures and the conclusions drawn are of use to the practitioner who must decide whether to use discrete or continuous modeling of acceptance sampling situations.
Abstract: A mathematical model for multiattribute acceptance sampling is developed. The number of defectives of each attribute in the lot is considered an independent random variable and is properly described by a discrete prior mass function. The concept of distributional reproducibility to hypergeometric sampling is invoked to simplify the expressions normally associated with a discrete model; yet, the model remains exact and may be efficiently optimized. The acceptance sampling situation modeled is identical to one previously published which applied continuous distributions to approximate the lot fraction defective. An extensive example problem is presented in which the two modeling approaches are compared using sensitivity measures. The conclusions drawn from the example are of use to the practitioner who must decide whether to use discrete or continuous modeling of acceptance sampling situations.
TL;DR: In this paper, the authors present two models for which the assumption of serial work station design is dropped, and the algorithms developed for operational design of such assembly lines are presented along with sample problems to demonstrate the computational procedures and advantages of these models.
Abstract: Traditionally assembly line balancing problems have been examined under the assumption of serial work station design. Thus no pair of work stations could be simultaneously working on the same copy of a product. This paper presents two models for which this assumption is dropped. The algorithms developed for operational design of such assembly lines are presented along with sample problems to demonstrate the computational procedures and advantages of these models.
TL;DR: In this paper, a discrete multi-facility model that analyzes tradeoffs between revenue implications and conventional cost considerations is presented, where prices realized and quantities demanded are dependent on the selection of facilities to supply each demand center.
Abstract: Facility location research has paid little attention to the revenue generation aspect of the location decision. However, the choice of facility locations can seriously influence the amount of revenue obtained through its effect on service factors such as delivery time and the compatibility of distribution systems. A discrete multi-facility model that analyzes tradeoffs between revenue implications and conventional cost considerations is presented. In this model, prices realized and quantities demanded are dependent on the selection of facilities to supply each demand center. The model is discussed from the standpoint of its potential application and is shown to have a number of practical advantages over the previous treatment of demand effects of facility location in the literature. This model is formulated as a zero-one linear program, and an exact algorithm for its solution is developed. The new algorithm is shown to be considerably more computationally efficient than a well-known code for zero...
TL;DR: An enumeration algorithm is presented for solving a scheduling problem similar to the single machine job shop problem with sequence dependent setup times, currently being used to develop typical observational timelines for a telescope that will be operated in earth orbit.
Abstract: An enumeration algorithm is presented for solving a scheduling problem similar to the single machine job shop problem with sequence dependent setup times. The scheduling problem differs from the job shop problem in two ways. First, its objective is to select an optimum subset of the available tasks to be performed during a fixed period of time. Secondly, each task scheduled is constrained to occur within its particular scheduling window. The algorithm is currently being used to develop typical observational timelines for a telescope that will be operated in earth orbit. Computational times associated with timeline development are presented.
TL;DR: In this paper, a methodology for modeling, analyzing, and evaluating cash flow streams is described, which is based on solutions to alpha/beta difference equations with easily estimated parameters and a wide variety of linear and nonlinear series patterns for solutions.
Abstract: Advantageous procedures in modeling, analyzing, and evaluating cash flow streams are possible with a new methodology described here. Modeling advantages are achieved through solutions to alpha/beta difference equations which have easily estimated parameters and a wide variety of linear and nonlinear series patterns for solutions. Marginal values and serial sums and averages facilitate regular or marginal analyses. When these solutions are given as time series, then zeta transforms of these series, with auxiliary developments, give discounted present values or a companion index of a specified finite series. Various applications serve to illustrate and verify the methodological procedures, as well as, demonstrate the analytical advantages.
TL;DR: In this article, the authors formulated the job shop problem with due dates to allow overlaps among successive operations on a job and proposed a procedure to generate multiple transport schedules for the manager's consideration.
Abstract: The job shop problem with due dates is formulated to allow overlaps among successive operations on a job. Multiple transports of sub lots and existence of setup times are two applications where this formulation can result in technologically feasible schedules. A procedure is described for generating overlap schedules and it is applied to eight test problems from the literature. The resulting schedules are compared to alternative schedules involving tardiness or overtime. The results indicate that the procedure is effective in generating multiple transport schedules for the manager's consideration. The comparative data provide useful tradeoff information for evaluation of alternatives and indicate that multiple transport scheduling may sometimes be a very economical way to try to meet due dates without using overtime operations.
TL;DR: A survey of the state-of-the-art in queueing theory directs attention to two areas—theory and applications—attempting to indicate their evolution to their present states.
Abstract: Approximately seven years ago T. L. Saaty wrote, “If one also takes the trouble to examine the (queueing) literature, …, he might get the idea that all those contributing to the understanding of congestion phenomena are interested in doing something about them …” This survey of the state-of-the-art in queueing theory directs attention to two areas—theory and applications—attempting to indicate their evolution to their present states. The appropriateness of Saaty's comment now is assessed, and based on this assessment some recommendations about what needs to be done are presented. The notion implied in the foregoing quotation, that if the queueing theorists were really interested in doing something about real-world problems they could, is subjected to scrutiny.
TL;DR: In this paper, an approximation model for determining minimum cost preventive maintenance schedules where accurate failure data are not available except the "average" (mean) and the "typical" value (mode) of the component lifetime is presented.
Abstract: This paper presents an approximation model for determining minimum cost preventive maintenance schedules where accurate failure data are not available except the “average” (mean) and the “typical” value (mode) of the component lifetime.