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Despite research suggesting that pro-environmental behaviors offer a range of positive benefits for organizations and that corporate social responsibility (CSR) positively affects employee behaviors and attitudes, very few studies have investigated how CSR affects pro-environmental behaviours. As such, this study investigates the impact of perceived CSR on employees' pro-environmental behaviours through organizational identification and coworkers' pro-environmental advocacy. Using a multistage sampling technique, a survey of line managers was conducted across 32 hotels in the understudied context of Malaysia's hotel industry. Based on 331 completed questionnaires, the results suggest that perceived CSR activities drive organizational identification and trigger coworkers’ pro-environmental advocacy, which in turn generate employees’ pro-environmental behaviours. The study offers valuable insights into the complex relationship between perceived CSR and pro-environmental behaviors and discusses the theoretical and research contributions and managerial implications.

This study investigated the mediating role of work meaningfulness on the relationship between employees' perception about organization's corporate social responsibility (CSR) practices and their engagement. Moreover, the joint moderating effects of incremental moral belief and moral identity centrality were also tested. Utilizing survey‐based data, this study analyzed the responses of 622 employees working in various industries. Results showed that incremental morality beliefs strengthened the effect of CSR perceptions on work meaningfulness, especially when moral identity centrality was weaker. Specifically, CSR perceptions had the strongest positive effect on work meaningfulness among employees with stronger incremental morality beliefs and weaker moral identity centrality. Another interesting finding of this study was that incremental morality beliefs strengthened the effect of CSR perception on employee engagement via work meaningfulness, especially when moral identity centrality was lower. This study found that CSR perceptions had the strongest positive effect on employee engagement via work meaningfulness among employees with stronger incremental morality beliefs and weaker moral identity centrality. The findings confirmed that incremental morality beliefs and moral identity centrality jointly moderated these relationships.

The primary aim of this study is to investigate how employees' corporate social responsibility (CSR) perceptions contribute to their voluntary pro‐environmental behaviors. This study also seeks to understand the moderating effects of employees' CSR motive attribution (substantive and symbolic) on the relationship between CSR perceptions and voluntary pro‐environmental behaviors. A questionnaire survey was conducted on 784 employees working in various industries such as telecommunication, pharmaceutical, medical, manufacturing, hospitality, and electronic. Results revealed that CSR perceptions positively affected voluntary pro‐environmental behaviors of employees. Moreover, employee's substantive CSR motive attribution strengthened the positive effect of CSR perceptions on voluntary pro‐environmental behavior, whereas symbolic CSR motive attribution weakened the positive effect of CSR perceptions on voluntary pro‐environmental behavior. This study provides guidance for managers who wish to address sustainability and CSR issues to enhance employees' voluntary pro‐environmental behavior. Organizations should integrate CSR initiatives into their sustainable strategy to increase employee's voluntary pro‐environmental behavior.

Corporate social responsibility (CSR) is a useful tool for effective organizational, social, and environmental functioning. This study expanded CSR and green research streams by examining the positive effect of employee's perceived CSR on pro‐environmental behaviour through mediation of organizational identification, as well as the moderation mechanisms of corporate entrepreneurship and employees' environmental consciousness for such an effect. The study drew on a survey sample of 479 employees and 122 department managers from various hotels in Pakistan. Key findings showed that CSR had both a direct and an indirect influence, through organizational identification, on pro‐environmental behaviour. The results lent support for the interactive effect of corporate entrepreneurship and environmental consciousness with CSR in predicting pro‐environmental behaviours. This is the first study of its kind to study a comprehensive model linking perceived CSR with employee's pro‐environmental behaviours in hotel industry through intervening variables.

In this study, the adsorption of methylene-blue (MB) and Cd(II) onto low cost material and easy separation towards cleaner environment was investigated. The cobalt ferrite embedded nitrogen doped carbon nanocomposite (CF@NC) was fabricated using albumen protein bi-metals complexes. The prepared nanocomposite was characterized using several analytical techniques. The electron microscopy results revealed that nanoparticles were spherical in the size range between 10 and 20 nm. The results of Brunauer–Emmett–Teller revealed that the fabricated nanocomposite (CF@NC) had porous nature and the surface area of this nanocomposite was found to be 691.82 m2g−1. The surface of CF@NC adsorbent had a negative charge, a value of about −27.5 mV determined by zeta potential measurement. The adsorption studies were carried out using different parameters such as pH, concentration of the pollutants, adsorption time and temperature for the adsorption of both pollutants. The adsorption kinetics supported the pseudo-second-order reaction and the adsorption isotherm supported the Langmuir isotherm models. The maximum adsorption capacity for Cd(II) and MB was estimated to be 245.09 mg g−1 and 421.94 mg g− 1. The results concluded that the prepared nanocomposite was a promising hybrid nanocomposites for the rapid adsorption of Cd(II) and MB from water.

Purpose Exploring factors that can influence employee's entrepreneurial intentions is critical to entrepreneurship and entrepreneurial practice. This study is going to examine the effect of narcissism on entrepreneurial intentions. Moreover, the mediating role of entrepreneurial self-efficacy in narcissism-entrepreneurial intentions link is also tested. Lastly, how environmental complexity moderates these relationships is explored. Design/methodology/approach Data were collected from 362 employees working in technology incubators and science parks of Saudi Arabia. These technology incubators and science parks were established by the Saudi government as a part of entrepreneurship ecosystem evolution strategy to encourage and support entrepreneurial innovations. Findings The results show that narcissistic employees display greater levels of entrepreneurial intentions, and entrepreneurial self-efficacy mediates the effect of narcissism on entrepreneurial intentions; and environmental complexity moderates the narcissism-entrepreneurial intentions link. Originality The effect of narcissism on entrepreneurial intentions has not been examined before. This study extends knowledge on entrepreneurial innovations by linking narcissism with entrepreneurial intentions through mediation of entrepreneurial self-efficacy and moderation of environmental complexity.

PurposeThe purpose of this paper is to investigate the actual benefits of radio frequency identification (RFID) on supply chain performance through the empirical evidence.Design/methodology/approachThe research reviews and classifies the existing quantitative empirical evidence of RFID on supply chain performance. The evidence is classified by process (operational or managerial) and for each process by effect (automational, informational, and transformational).FindingsThe empirical evidence shows that the major effects from the implementation of RFID are automational effects on operational processes followed by informational effects on managerial processes. The RFID implementation has not reached transformational level on either operational or managerial processes. RFID has an automational effect on operational processes through inventory control and efficiency improvements. An informational effect for managerial processes is observed for improved decision quality, production control and the effectiveness of retail sales and promotions coordination. In addition, a three‐stage model is proposed to explain the effects of RFID on the supply chain.Research limitations/implicationsLimitations of this research include the use of secondary sources and the lack of consistency in performance measure definitions. Future research could focus on detailed case studies that investigate cross‐functional applications across the organization and the supply chain.Practical implicationsFor managers, the empirical evidence presented can help them identify implementation areas where RFID can have the greatest impact. The data can be used to build the business case for RFID and therefore better estimate ROI and the payback period.Originality/valueThis research fills a void in the literature by providing practitioners and researchers with a better understanding of the quantitative benefits of RFID in the supply chain.

The purpose of this study is to compare a focused cellular manufacturing environment with traditional cellular manufacturing, and job shop environments. We define focused cellular manufacturing as a configuration scheme that groups components by end-items and forms cells of machines to fabricate and assemble end-items. In addition, this research includes three levels of batch sizes and two levels of set-up times in its performance criteria which few researchers in this area have done. The results indicate that the focused cellular manufacturing scheme has a batching advantage. This advantage dominated the balanced machine utilization benefit of the job shop configuration scheme and out weighed the set-up time reduction advantage of the cellular manufacturing scheme for average end-item completion times and average work-in-process inventory levels. The cellular manufacturing and job shop schemes overcame the batch size advantage only when batch sizes were small or set-up times were large.

The development of a profitable-to-promise order management model in a make-to-order manufacturing environment is presented. The primary objective is to maximize profitability while ensuring that the firm has adequate resources to satisfy demand. The effectiveness of Activity-Based Costing and Theory of Constraints-based approaches is compared to assess order profitability. This order management model uses a mixed-integer program to consider simultaneously capacity, the relevant costs of supply chain resources and profitability. The results suggest that a close examination of cost structures is necessary for choosing an effective framework for a profitable-to-promise application. In manufacturing environments where direct manufacturing costs constitute a relatively small percentage of the total manufacturing cost, it would be beneficial to consider an Activity-Based Costing approach. On the other hand, in environments where direct costs are large, a Theory of Constraints-based approach would suffice.

This paper is aimed at comparing cellular manufacturing with focused cellular manufacturing. We define focused cellular manufacturing as a layout scheme that groups components by end‐items and forms cells of machines to fabricate and assemble end‐items. It is not classified as a cellular manufacturing layout since it does not attempt to take advantage of process similarities. It also is not classified as a flow shop since there are no machines dedicated to individual operations and the machines are not arranged in a series. In addition, this research includes batching and assemble times in its criteria which few researchers in this area have done. The results indicate that the focused cellular manufacturing scheme has a batching advantage. This advantage out‐weighed the set‐up time reduction advantage of the cellular manufacturing scheme for average end‐item completion times and average work‐in‐process inventory levels. The cellular manufacturing scheme overcame the batching advantage only when there were small batch sizes or large set‐up time magnitudes.

It is now well known that most major companies no longer operate in a single market. To penetrate global markets and obtain their benefits, companies are under tremendous pressure to reduce the price of their products, and thus their production and material costs. When a foreign location is used, the components of a product are produced there and final assembly takes place either at the foreign location or at the parent domestic plant. This paper first presents the issues related to international facilities location (IFL) problems, and provides the framework required to deal with such problems. It then presents a heuristic algorithm for solving the IFL problem. Extensive computational experience was gained by solving a variety of IFL problems of different sizes.

The global manufacturing research group (GMRG) is a multi‐national group of researchers who are dedicated to the study and improvement of manufacturing practices worldwide. The GMRG developed a survey that has been administered to companies in the machine tools and non‐fashion textile industries. In this study we utilize the GMRG data collected during 1993‐1995 and we focus on improvement programs and their impact on performance outcomes. Specifically, the improvement programs of interest are cellular manufacturing, factory automation, just‐in‐time (JIT) systems, and total quality management (TQM); the performance measures used were the percentage change in manufacturing cost, product quality, delivery speed, and on‐time deliveries. The relationships among the programs and outcomes were modelled and analyzed using the partial least squares (PLS) approach to structural equation modelling (SEM).

This paper reports the results of our collaborative work with Changde Telecommunication Equipment Company (CTEC) which produces digital transfer control systems for telephone networks. The manufacturing operations consist of two principle stages of module production and system assembly. Critical system components are produced in the module production stage where high inventories were a major managerial concern. We studied CTEC’s module production system and proposed three modifications to reduce inventories and improve system performance. The current system and the proposed modifications were simulated and compared in terms of various operational and financial criteria. The simulation was repeated in its entirety under a high level of demand due to CTEC’s anticipation of increased market share. The results, endorsed by CTEC’s management, demonstrate that significant operational and financial benefits can indeed be realized using the proposed modifications. This study provides motivation for the development of concepts and methodologies that will be useful in future theoretical and practical research.

This empirical research study investigates the manufacturing planning and control (MPC) practices associated with successful company performance. To form a database of global manufacturing practices, data collected from machine tools and textile industries in 12 countries around the world via the Global Manufacturing Research Survey was combined. An exploratory factor analysis was first conducted to reduce the dimensionality of the data. Three Discriminant Analyses were then performed on the factor scores of successful and non-successful companies, between free and planned economies and among the 12 countries represented in the database, with an emphasis on the factors found to be associated with success. The results show that close coordination of several business functions with the MPC system is essential for success. Significant differences were found between state-managed and free-market economies and among the countries represented in the database. In general, countries with free-market economies had high success coefficients, led by Japan, which had the most combined use of essential success factors, while countries with planned economies had low success coefficients.

In today's markets, customers want to buy the best quality products at the lowest prices, regardless of where they are produced. Hence, most companies can no longer afford to operate in a single domestic market. To penetrate global markets and obtain their benefits, companies are under tremendous pressure to be competitive and to reduce their production costs. Establishing foreign manufacturing facilities has therefore been taking place rapidly and is further enhanced by trade agreements such as NAFTA. Even though there has been much written on facilities location, in general the literature on international facilities location is rather limited. This paper surveys the available literature and provides an efficient branch and bound procedure for solving the uncapacitated multi-period international facilities location problem. This branch and bound procedure is applied to a case study and tested for its efficiency. The solutions and computation times are compared with those obtained using LINDO. This extens...

Often in lean manufacturing, multiple products are produced in U-shaped manufacturing cells to simultaneously achieve product variety and production efficiency. We examine two design issues for mixed-model U-lines: work rules (a first-come-first-serve rule and a crossover-and-return rule) and inventory flow choices (direct flow and buffered flow). Simulation results indicated that throughput and labor utilization can be improved by implementing a “buffer” with the first-come-first-serve rule. Interestingly, the effectiveness of an inventory flow choice was dependent on the work rule (interaction effect), and relationships among performance dimensions differed across the designs.

For many years, facilities location problems have attracted a great deal of attention in the literature. As a result, there is now a variety of methods for solving these problems. However, due to the recent interest, little research is found relating to the issues concerning international facilities location problems. Furthermore, in spite of the extensive modelling work done on facilities location, little modelling research exists on location problems. Provides a capacitated multi‐period, 0‐1 mixed integer programming formulation for the international facilities location problem and discusses its applications to an actual company case. This application is carried out to demonstrate not only how the model can be applied in practice but also to show its potential benefits when compared to other methods.

This paper considers the permutation flowshop scheduling problem with significant sequence dependent set-up times and develops a savings index heuristic algorithm to find an approximately minimum makespan schedule. The proposed algorithm determines the savings in time associated with a particular sequence and selects the sequence with the maximum time savings as the best heuristic solution. Computational experience indicating the effectiveness and efficiency of the proposed savings index heuristic algorithm are reported and discussed.

American designers are designing more flexibility into flexible manufacturing systems (FMSs). However, there has been little research on the scheduling of these more flexible systems. This study adds insights into how these systems should be scheduled and increases our understanding of the influences of routing flexibility. A few American FMSs use off-line schemes for scheduling but most use real-time schemes. This research compares seven real-time and two off-line scheduling schemes for a random flexible manufacturing system. The results indicate that full advantage can be taken of these more flexible systems if off-line schemes are used. The scheme that takes the greatest advantage of increased flexibility is an off-line scheme that decomposes the scheduling problem. As flexibility increases this scheme is able to schedule more output and reduce the average flow time of parts, and it accomplishes this with little additional computational effort.

Mixed-model assembly lines often create model imbalance due to differences in task times for the different product models. Smoothing algorithms guided by meta-heuristics that can escape local optimums can be used to reduce model imbalance. In this research, we utilise the meta-heuristics tabu search (TS), the great deluge algorithm (GDA) and record-to-record travel (RTR) to reduce three objective functions: the absolute deviation from cycle time, the maximum deviation from cycle time, and the sum of the cycle time violations. We found that the GDA was significantly superior to the RTR and TS algorithms across all problem sizes and objective functions. For the 19 task problems, RTR performed significantly better than TS for all three objective functions. On the other hand, for the 61 and 111 task problems TS performed significantly better than RTR for all three objective functions.

This paper is motivated by the need for developing well-structured methodologies and mechanisms that enable an efficient coordination of swap/exchange transactions among same-level supply chain partners in the petroleum and energy industries. A mathematical model that can capture the complexity in the swap transactions between two companies is presented. The model is then applied to a real case study from the petrochemicals industry, and the solutions of the model are evaluated and their performances are compared to those of current industry practices.

SUMMARY The research on lot sizing is extensive; however, no author in the literature reviewed to date provides an optimal solution algorithm to a prevalent problem which is found in manufacturing. A multi-level, general product-structure, variable-cost model is presented which follows the procedure of a closed-loop material requirements planning (MRP) system, and incorporates many conditions that production and material managers find in practice. A branch and bound (B&B7) algorithm is developed. The efficiency of B&B is derived from effective lower bounds and solution procedures which are determined on the basis of the space-time structure of the MRP lot-sizing problem and its non-convex total-cost function. This path-dependent lower bound is computationally efficient and guarantees an optimal solution. The B&B algorithm is tested on problems and compared to heuristics in the literature.

Multi-activity, multi-facility design systems occur in a wide variety of industrial and service applications: e.g.: regional health care centers with configurations of activities at each center, and multi-echelon inventory distribution systems. The problem in designing such systems is to determine from a candidate set of possible locations what facility locations should be opened and what types of activities should be carried out at each of the open facilities. This article presents an efficient heuristic procedure for such a problem. The heuristic procedure described can be used to solve both the uncapacitated and the capacitated problems where capacity is expressed in terms of the number of activities which can be supported by the facilities. Extensive computational experience with the heuristic is presented. The performance of the heuristic is compared against optimal solutions and the results look very encouraging.

The National Aeronautics and Space Administration (NASA) is charged with developing a Flight Operations Planning Schedule for Space Shuttle Operations in the 1980s. During this decade, NASA plans to launch up to thirty space shuttle flights per year when the program reaches the mature phase. Traditional planning techniques for space flights (PERT-type models) are inadequate for this task because of their inability to resolve conflicts arising from multiple demands for limited resources generated by numerous simultaneous projects (space flights). This paper describes a requirements planning system developed by the authors and adopted by NASA for this resource constrained multiple project scheduling problem.

Two heuristics based on branch and bound (BB thus, LAM efficiently uses computer-storage capacity and allows solution of larger problems. The “total average modification'’(TAM) heuristic uses B&B, applied level by level, and modified setup and carrying costs to solve the variable production/purchasing costs MRP lot-sizing problem. LAM and TAM are tested on problems and compared to heuristics in the literature. TAM may be used to solve large MRP lot-sizing problems encountered in practice.

The branch and bound method was used to find the “best” number of sales regions and to reconfigure regional boundaries for the Variable Annuity Life Insurance Company (VALIC). The solution specified (1) an increase in sales regions from 16 to 25, and (2) the geographic customer base to be served by each region. Savings were estimated to be $8,833,000.

The conventional approach to the assembly line balancing problem assumes that the manufacturing methods to be used have been predetermined. However, in practice the design engineer has several alternatives available in the choice of processing, typically involving a trade-off between labor or capital intensive options. The choice of manufacturing method is frequently viewed as an investment or capital budgeting decision, contrasting projected savings in labor cost with the additional fixed cost for the more capital intensive alternatives. The manufacturing tasks (based on the selected processing alternatives) are then assigned to work stations so as to minimize the number of work stations (i.e., labor costs) necessary to achieve a desired production rate. This paper describes a method of simultaneously considering both the choice of manufacturing alternatives and the assignment of tasks to stations so as to minimize total costs (labor and fixed) over the expected life of the production line. The importance of considering these decisions jointly results from the fact that the benefits obtained from specific manufacturing alternatives should not be limited to anticipated labor savings alone. The true measure of achievable labor savings can only be determined after an assignment of tasks to stations has been chosen. For instance, although a processing alternative may reduce the total work content of a set of tasks, if the resulting line balancing assignment does not reduce the number of stations required to achieve a desired production rate, the assumed savings will not be achievable and will serve only to increase the idle time of the line. On the other hand, an apparently trivial reduction in the time to complete a certain task may lead to a more efficiently balanced line, producing a much greater real savings in labor cost than had been anticipated, due to a reduction in both work content and idle time for the line. The combined processing alternative line balancing problem can be formulated as an integer programming problem. Two alternate formulations are provided which differ in the degree of flexibility in selecting a cycle time. A branch and bound procedure is described for the fixed cycle time situation which takes advantage of the special structure of the problem to provide an efficient method capable of solving problems of practical interest. The effectiveness of the proposed procedure is demonstrated by application to an actual redesign of an assembly line for a major auto-industry supplier.

In this paper a heuristic procedure is developed for solving the problem of planning machine replacements for a serially dependent production system. Given a finite planning horizon, the decision-maker wishes to decide (1) which periods, if any, that the entire production system must be shut down in order to make replacements, and (2) what specific machine or machines in the system should be scheduled for replacement during each of these downtime periods. The problem involves a balancing of costs. If the production system is brought down to make one or more replacements a fixed downtime cost is incurred; this cost is independent of the machines replaced during the downtime. In addition, other fixed coats are incurred for each of the machines replaced. Our motivation for scheduling these replacements is to realize lower variable costs for operating the machines. The variable operating costs are assumed to increase as the age or vintage of the machines increases. An optimal replacement policy is one in whic...

An important problem confronting health care administration is cost containment in hospitals. Much of the current high costs can be traced directly to outdated procedures in materials management leading to waste, excessive inventory and unnecessary obsolescence of expensive short shelf life items. In this paper, we illustrate how a modern requirements planning system for surgical supplies was developed for a private hospital in Houston and used to effectively hold inventory levels to the minimum required to support a detailed schedule of surgical procedures. We also discuss some specific problems involved in the transfer of manufacturing technology to the hospital setting.

The mixed integer-linear models that have been used in most analyses of warehouse location problems fail to capture the potential operating efficiencies associated with large scale facilities. This paper presents an algorithm for finding a minimal cost warehouse system design wherein individual warehouses have limited capacities and exhibit economies of scale. The iterative procedure defines and solves a series of conventional transportation problems in order to converge on the optimal system design. The algorithm is well suited to solving large problems of the type commonly encountered in practice.

Within the past several years, considerable research has been devoted to the aggregate production planning problem starting with the pioneering work of Holt el al, (1955) and the resulting Linear Decision Rule (LDR). However, researchers have also recognized that developing optimal aggregate production plans, per se, is not sufficient for solving real problems; these plans have to be disaggregated into specific schedules for specific products. Consequently, the thrust of current research is on the ‘disaggregation’ problem. Simultaneously a number of companies have been installing MRP systems with reports of significant improvements in inventory control, production planning, work force scheduling and production costs. This paper reports on an experiment which was designed and conducted to compare the effectiveness of the ‘aggregate-disaggregate’ and MRP approaches to production planning in a simulation environment. LDR was used as the optimal aggregate technique in the aggregate-disaggregate appro...

The objective of this note is (i) to identify and briefly review some references not included in [El-Shaieb, A. M. 1973. A new algorithm for locating sources among destinations. Management Sci. 20 221–231.] as well as more recent additions and (ii) to give computational comparisons of three other solution methods with that of El-Shaieb on his 30-city test data.

SUMMARY A critical assumption in balancing assembly lines is that the line is ‘ serial ’ with no ‘ paralleling’ of tasks allowed. This constrains the cycle time to be at least equal to the maximum task time, which in turn limits the production rate. One alternative to increasing the production rate (hence lowering the cycle time) is by allowing parallel tasks in the assembly line at the cost of additional facilities. In this case, the problem becomes one of selecting the tasks to be paralleled such that the total cost is minimized. This problem is formulated as a mixed integer programme, and a branch and bound algorithm is presented for its solution. The structural properties of this programming problem are discussed, which con be used to improve the computational efficiency of our branch and bound algorithm. An illustrative problem and preliminary computational results are provided.

The multi-asset investment renewal problem is characterized by two types of costs: transaction costs incurred when any renewal takes place at a point in time, and investment costs which are associated with renewing individual assets. A discrete-time version of this renewal scheduling problem is formulated as an integer program that, due to its structure, admits to an efficient branch and bound approach to solution. Computational experience with the solution algorithm is presented.

This paper presents the development and application of a heuristic scheduling rule for the Testing Department of a tyre and rubber company. The company had set down five major objectives for this department: (1) minimize average flow-time; (2) maintain an average flow-time of less than two weeks; (3) maintain pre-set maximum individual test flow times; (4) assign a higher priority to important jobs; (5) maintain a balanced mix between truck and passenger tyres. A composite scheduling rule was designed to meet these objectives which contains the following four components: (a) slack-time per remaining operation; (b) shortest processing time; (c) an urgency factor to prioritize important jobs; (d) a balancing factor to enable a desired proportion between truck and passenger tyres. This composite rule is tested against the existing scheduling scheme used by the foreman and against the simple S.P.T. rule. The results are very encouraging.

The planning of production, inventories, and work force at an aggregate level to respond to fluctuating demands on a production system has received substantial theoretical treatment in the literature for several years. However, widespread implementation of the available analytical techniques has not occurred. The objectives of this research are to explore this implementation problem: (1) by developing a simulation model of an operating firm, (2) by using this simulation to compare the performance of aggregate production planning models, and (3) by formulating a generalized methodology for implementing quantitative planning models into the decision procedures of operating firms.

This paper describes an efficient solution procedure for the warehouse location problem in which limitations on the amount of goods which can be handled are also imposed. The proposed branch-and-bound solution method is made efficient by developing dominance, lower and upper bounding procedures and branch and node selection rules utilizing the special structure of this problem. Computational results are provided for large sized problems.

This study was prompted by a recently published article in this journal on facility location by D. R. Sule. We show that the claim made by Sule of a novel and extremely simple algorithm yielding optimum solutions is not true. Otherwise, the algorithm would represent a breakthrough in decision-making for which a number of notoriously hard problems could be efficiently recast as location problems and easily solved. In addition, several variants of common location problems addressed by Sule are reviewed. In the last twenty years, many methods of accurately solving these problems have been proposed. In spite of their increased sophistication and efficiency, none of them claims to be a panacea. Therefore, researchers have concurrently developed a battery of fast but approximate solution techniques. Sule's method was essentially proposed by Kuehn and Hamburger in 1963, and has been adapted many times since. We exhibit several examples (including the one employed by Sule) in which Sule's algorithms lead to nonoptimal solutions. We present computational results on problems of size even greater than those utilized by Sule, and show that a method devised by Erlenkotter is both faster and yields better results. In a cost-benefit analysis of exact and approximate methods, we conclude that planning consists of generating an array of corporate scenarios, submitting them to the “optimizing black box,” and evaluating their respective merits. Therefore, much is to be gained by eliminating the vagaries of the black box—that is, by using an exact method—even if the data collection and the model representation introduce sizable inaccuracies. Ironically, large problems (those that typically require most attention) cannot be solved exactly in acceptable computational times. Pending the imminent design of a new generation of exact algorithms, the best heuristics are those that guarantee a certain degree of accuracy of their solutions.

This note shows two easily incorporated improvements in computing the lower bounds for Warszawski's branch and bound algorithm for the multi-commodity location problem. The lower bounds become relatively stronger, thereby making the branch and bound algorithm more efficient.

Distribution systems designs commonly require the optimal location decisions of regional ware-houses or distribution centers which function as intermediate facilities between plants and customers. This paper deals with such a location problem in which the facilities can handle one of several commodities. We term this problem the multi-commodity facility location problem. A branch and bound algorithm is proposed for solving this problem. Improved bounds are developed for increasing the efficiency of the algorithm. Computational results are provided.

This note questions the authors' claim for optimality in designing cusum charts using the heuristic pattern search method.

This paper introduces an efficient branch and bound algorithm for a special class of mixed integer programming problems called the warehouse location problem. A set of branching decision rules is proposed for selecting warehouses to be constrained open and closed from any node of the branch and bound tree. These rules are tested for their efficiency in reducing computation times and storage requirements to reach optimal solutions. An improved method of solving the linear programming problems at the nodes which substantially reduces the computations is also introduced in this paper.