Showing papers in "Interfaces in 1986"
TL;DR: In this article, the analytic hierarchy process (AHP) and its applications in diverse decision problems are briefly reviewed and some of the major extensions and criticisms of the method are discussed.
Abstract: This paper briefly reviews the analytic hierarchy process (AHP) and its applications in diverse decision problems. It addresses some of the major extensions and criticisms of the method, as well.
1,296 citations
TL;DR: In this article, a comparative site analysis was made by applying Data Envelopment Analysis (DEA), incorporating project cost, user time delay, and environmental impact data, and arguments were developed to bracket these pairs of price weights into an "assurance region" for the preferred site(s).
Abstract: In 1984, the Texas Legislature funded a four-university, interdisciplinary effort to identify feasible sites for location of a very high-energy physics lab in Texas and to evaluate the comparative advantages of one site versus another. Six feasible sites were identified and a comparative site analysis was made by applying Data Envelopment Analysis (DEA), incorporating project cost, user time delay, and environmental impact data. In addition, for the efficient sites, the price weights for user time delay and environmental impact, given normalization on project cost, were analyzed and arguments were developed to bracket these pairs of price weights into an “assurance region” for the preferred site(s). The South Dallas site was found to be preferred for a wide range of conditions, while the North Houston site was sensitive to the method of indexing the impact of the environment. The method appears to be applicable to a wide range of siting problems faced by not only government, but also industry.
676 citations
TL;DR: In this paper, a stochastic dynamic programming model, SDP, determines the optimal allocation of hydro and thermal resources in a large Brazilian multi-owned hydrothermal generating system.
Abstract: Coordination of the operation of the large Brazilian multi-owned hydrothermal generating system, at the institutional level, was achieved through a pool structure in which all member utilities share the cost of operating the thermoelectric system. At the technical level, a stochastic dynamic programming model, SDP, determines the optimal allocation of hydro and thermal resources in the system. The SDP model was extensively validated by 18 electrical utilities and officially adopted by the pool in 1979. Comparisons with a previously adopted model projected expected savings of $87 million in five years, a 28 percent reduction in operating costs. Actual savings from 1979 to 1984 are about $260 million. The SDP model is also the focal point of a chain of generation expansion models, insuring that the probabilistic criteria used for planning and the operation of the Brazilian system are compatible.
93 citations
TL;DR: In this article, the value of combining forecasts has been investigated and the results have led to significant gains in our ability to forecast and to help people to use forecasts, especially in the area of judgmental forecasting.
Abstract: Before 1960, little empirical research was done on forecasting methods. Since then, the literature has grown rapidly, especially in the area of judgmental forecasting. This research supports and adds to the forecasting guidelines proposed before 1960, such as the value of combining forecasts. New findings have led to significant gains in our ability to forecast and to help people to use forecasts.
83 citations
TL;DR: The United Airlines has developed and implemented a computerized station manpower planning system for scheduling shift work at its reservations offices and airports as mentioned in this paper, which utilizes integer and linear programming and network optimization techniques.
Abstract: United Airlines has developed and implemented a computerized station manpower planning system for scheduling shift work at its reservations offices and airports. The system utilizes integer and linear programming and network optimization techniques and encompasses the entire scheduling process from forecasting of requirements to printing employee schedule choices. Since its implementation in 1983, it has been used to develop work schedules for 4,000 employees on a regular basis and is eventually expected to schedule 10,000 employees or 20 percent of United's total work force. The system has produced direct labor cost savings of over $6 million annually while earning rave reviews from United upper management, operating managers, and affected employees.
80 citations
TL;DR: For about 25 years, attempts have been made to schedule classes and meetings by computer (to timetable) by computer in Germany, and during the last 12 years several programs for mainframe computers have been used on a large scale.
Abstract: For about 25 years, attempts have been made to schedule classes and meetings (to timetable) by computer. In Germany, many programs have been developed, and during the last 12 years several programs for mainframe computers have been used on a large scale. During the last five years, more and more schools are using microcomputers to produce their timetables.
62 citations
TL;DR: In this paper, two systematic methods are used to elicit and organize value attributes and identify the value attributes is an early and important step in such an analysis; two systematic approaches are described.
Abstract: Currently, structuring decision problems is more art than science. A useful decision analysis should characterize and discriminate between alternatives so that the decision maker can make an informed decision. Identifying the value attributes is an early and important step in such an analysis; two systematic methods are used to elicit and organize value attributes.
62 citations
TL;DR: As the spreadsheet evolves further, the management science specialist and the generalist user will come together to form a powerful team.
Abstract: Spreadsheet modeling software has evolved to the point where it now provides generalists with the power to analyze their own decisions quickly and easily. These new “modelers” aspiring to extend their spreadsheet experience will find further possibilities in decision tree analysis, expert systems, optimization, risk analysis simulation, and statistical analysis and forecasting. As the spreadsheet evolves further, the management science specialist and the generalist user will come together to form a powerful team.
60 citations
TL;DR: A large 0-1 integer program is approximately solved by a very fast heuristic as part of a decision support system for assigning classes to rooms at the University of California at Berkeley.
Abstract: A large 0-1 integer program is approximately solved by a very fast heuristic as part of a decision support system for assigning classes to rooms at the University of California at Berkeley. The system has been implemented and has been in regular use since the fall of 1983.
46 citations
TL;DR: A study was carried out to assist in the relocation of the Red Cross Blood Donor Clinic and Transfusion Center in Quebec City and provides advice based on sparse data.
Abstract: A study was carried out to assist in the relocation of the Red Cross Blood Donor Clinic and Transfusion Center in Quebec City. While models for this type of problem exist, many of them are data-hungry. This one provides advice based on sparse data.
38 citations
TL;DR: The new projective scaling algorithm for linear programming has caused quite a stir in the press, mainly because of reports that it is 50 times faster than the simplex method on large problems and has a polynomial bound on worst-case running time that is better than the ellipsoid algorithm's.
Abstract: N. Karmarkar’s new projective scaling algorithm for linear programming has caused quite a stir in the press, mainly because of reports that it is 50 times faster than the simplex method on large problems. It also has a polynomial bound on worst-case running time that is better than the ellipsoid algorithm’s. Radically different from the simplex method, it moves through the interior of the polytope, transforming the space at each step to place the current point at the polytope’s center. The algorithm is described in enough detail to enable one to write one’s own computer code and to understand why it has polynomial running time. Some recent attempts to make the algorithm live up to its promise are also reviewed.
TL;DR: In this paper, the authors proposed a heuristic for routing special education students in an urban environment, where the students must be picked up at home and delivered to selected schools which meet their specific educational needs.
Abstract: In routing special-education students in an urban environment, the students must be picked up at home and delivered to selected schools which meet their specific educational needs. In addition to the many-to-several problem structure, special sequencing restrictions and route duration limitations exist. Heuristics can achieve significant savings for both route distance and route duration, and a shuttle system is also found to be effective.
TL;DR: A group of US and Chinese analysts helped plan for comprehensive water pollution control of the Huangpu River in Shanghai, exploring normative decision analysis as one tool as discussed by the authors, trying to adapt this quintessential Western way of thinking to the Chinese decision-making structure.
Abstract: A group of US and Chinese analysts helped plan for comprehensive water pollution control of the Huangpu River in Shanghai, exploring normative decision analysis as one tool. Trying to adapt this quintessential Western way of thinking to the Chinese decision-making structure was interesting and instructive.
TL;DR: In this paper, the authors proposed a package of cost-effective improvements for capacity expansion, which included closely spaced intermediate signals and strategically located sections of double track, for Canadian National Railway's already congested single track main line.
Abstract: In the late 1970s, traffic volumes over the next decade were predicted to double on Canadian National Railway's already congested single track main line. As part of a plant expansion program, a transportation planning research team developed two “what-if” simulation models to evaluate the relative effect of the many factors influencing main line capacity. When used together, they predict train delay under various track and signal designs, operating methods, and traffic scenarios. We then proposed a package of cost-effective improvements for capacity expansion, which included closely spaced intermediate signals and strategically located sections of double track. These improvements, together with the application of the simulation models to plant design, have enabled CN to defer capital expenditures of over C$350 million beyond the 1980s.
TL;DR: In this paper, a rigorous proof of Andersen's theorem is given, and it is shown that operations research specialists are like car-repairmen who rebuild the engine when a tune-up would do.
Abstract: This paper gives a rigorous proof of Joe’s theorem. It also provides a novel presentation of Andersen’s conjecture, and it shows why some operations research specialists are like car-repairmen who rebuild the engine when a tune-up would do.
TL;DR: The real message of the essay is that the authors all have second thoughts about some of their papers and that it is healthy to acknowledge and laugh about them.
Abstract: Entitled “Pulling the Goalie Revisited,” the piece goes beyond discussing a misapplication to make use of some entirely new hockey-league data. And though it's true that the original analysis contained a flaw, there are as many MS/OR professionals who failed to spot it as there are shoes in the closet of Imelda Marcos. The real message of the essay is that we all have second thoughts about some of our papers and that it is healthy to acknowledge and laugh about them. Indeed, a correlation appears to exist: the professions least able to laugh at themselves seem the ones most laughed at by others.
TL;DR: Citgo Petroleum Corporation has recently realized a reduction in petroleum products inventory of $116 million (based on historical inventory-to-sales ratios), resulting in annual interest savings of $14 million, as well as improvements in coordination, pricing, and purchasing decisions estimated at $2.5 million annually.
Abstract: Citgo Petroleum Corporation has recently realized a reduction in petroleum products inventory of $116 million (based on historical inventory-to-sales ratios), resulting in annual interest savings of $14 million, as well as improvements in coordination, pricing, and purchasing decisions estimated at $2.5 million annually. An optimization-based decision support system coupled with a state-of-the-art, on-line corporate data base provides management with the information which resulted in these benefits. These profit improvements are the documented benefits of an approach which combines management science and top management skills to achieve a comprehensive program for controlling working capital and planning operations.
TL;DR: The fact-net model, a diagnostic procedure developed by the authors, is applied to a real-world, unstructured operational problem along with two other currently used methods, and the three methods are compared.
Abstract: Solving the wrong problem, or type 3 error, is often what separates the effective from the ineffective management scientist. Management scientists commit type 3 errors because they lack formal training in problem identification techniques. There are logical and rational problem identification approaches for diagnosing operational, managerial, and strategic problems. The fact-net model, a diagnostic procedure developed by the authors, is applied to a real-world, unstructured operational problem along with two other currently used methods, and the three methods are compared.
TL;DR: In this article, six rules are used to select among seven exponential smoothing models (to pick the model that yields the lowest error on a fit to historical data) Comparisons of accuracy are made among forecasts generated by the selection rules and the individual smoothing model, and results indicate that the use of rules leads to increases in accuracy.
Abstract: Six rules are used to select among seven exponential smoothing models (to pick the model that yields the lowest error on a fit to historical data) Comparisons of accuracy are made among forecasts generated by the selection rules and the individual smoothing models The results indicate that the use of rules leads to increases in accuracy A combination of selection rules led to the most accurate forecasts The rules also led to lower variances in the accuracy of forecasts, that is, they help to avoid large errors
TL;DR: In this article, the authors propose to use management science and operations research to help modernize the country, however, the traditions of China, as well as its recent past, make the effective application of MS/OR problematical.
Abstract: Apparently the leaders of China intend to use management science and operations research to help modernize the country. However, the traditions of China, as well as its recent past, make the effective application of MS/OR problematical.
TL;DR: Imprecise data can be used to provide an objective evaluation of the benefits of an IS and serve as a “gate keeper” to screen out unjustifiable ISs before a costly analysis is performed.
Abstract: Information systems (ISs) are used by high-level management to support the decision-making process. The decision to proceed from an initial IS evaluation to a costly, in-depth analysis must be based upon the value of using the IS. Management tends to avoid objective evaluation of an IS because many of the benefits (and costs) are intangible and difficult to quantify with precision. However, imprecise data can be used to provide an objective evaluation of the benefits of an IS. Such an evaluation may serve as a “gate keeper” to screen out unjustifiable ISs before a costly analysis is performed.
TL;DR: Hoesch Siegerlandwerke AG developed a computer-based strategic planning system to replace the manual planning system and enable the company to consider alternative plans easily, to perform mass calculations and cost accounting operations quickly, and to maximize efficiency as discussed by the authors.
Abstract: Hoesch Siegerlandwerke AG developed a computer-based strategic planning system to replace the manual planning system and enable the company to consider alternative plans easily, to perform mass calculations and cost accounting operations quickly, and to maximize efficiency.
TL;DR: In this paper, a decision analytic model was used to choose between two site locations for drilling an oil well, the decision maker considered geological and engineering factors in light of his attitudes toward risk and money.
Abstract: The decision environment in which an independent oil and gas producer operates is extremely complex. In a specific case a decision analytic model was found to be useful. To choose between two site locations for drilling an oil well, the decision maker considered geological and engineering factors in light of his attitudes toward risk and money. A decision-tree analysis provided a framework for systematically analyzing the problem and reaching a decision.
TL;DR: The VISION decision simulator was developed to implement dynamic programming-based improvements in raw materials returns at Weyerhaeuser as mentioned in this paper, and the resulting operational benefits exceed $100 million in increased profits.
Abstract: The VISION decision simulator was developed to implement dynamic-programming-based improvements in raw materials returns at Weyerhaeuser. Operational benefits to date exceed $100 million in increased profits. In addition, management philosophy has been changed, and, with the recent weakening in forest product markets, VISION benefits have increased in importance.
TL;DR: Scenarios as mentioned in this paper is a tool for forecasting long-range, complex, and highly uncertain business environments, which offers logically consistent sets of conditions, trend analysis, and simulated models for strategic business planning.
Abstract: Scenarios provide a tool for forecasting long-range, complex, and highly uncertain business environments. They offer logically consistent sets of conditions, trend analysis, and simulated models for strategic business planning. Scenarios are applicable to the planning needs of aerospace and defense companies, whose principal customer is the US Department of Defense. The case history reviews the experience of Battelle and the Goodyear Aerospace Corporation in forecasting by use of scenarios the international environment and US defense expenditures to 1995 and deriving strategic business plans from them.
TL;DR: In this paper, researchers from the US and China apply optimization methodology to the problem of scheduling a bulk-pickup-and-delivery fleet for a fleet operation in Shanghai.
Abstract: Researchers from the US and China apply optimization methodology to the problem of scheduling a bulk-pickup-and-delivery fleet for a fleet operation in Shanghai. Preliminary observations on the problem and on the differences and similarities in the application of MS/OR in China and the US are offered.
TL;DR: A Greek manufacturer of printed circuit boards achieved a significant improvement in the performance of a programmable drilling machine by using a traveling salesman heuristic as discussed by the authors, which was carried out on the company's small personal computer using BASIC.
Abstract: A Greek manufacturer of printed circuit boards achieved a significant improvement in the performance of a programmable drilling machine by using a traveling salesman heuristic. Most of the development work was carried out on the company’s small personal computer using BASIC. In order to tackle larger drilling tasks and to facilitate the input process, the BASIC program was translated into machine code and a drilling machine-computer interface was designed, leading finally to the manufacture of a drilling optimization device.
TL;DR: In fact, things are not all bad with MS/OR as discussed by the authors : there is a widely shared consensus on the basic goals of the profession and the future holds great promise, partly because of several favorable external developments.
Abstract: Things are not all bad with MS/OR. In fact things are pretty good: There is a widely shared consensus on the basic goals of the profession. We have made substantial progress towards these goals. And the future holds great promise, partly because of several favorable external developments.
TL;DR: A survey of 64 private and government organizations in Finland revealed that they used over 150 different operations research models as discussed by the authors, based on published reports, interviews with representatives of university departments, and personal observations.
Abstract: A survey of 64 private and government organizations in Finland revealed that they used over 150 different operations research models. Academic operations research was reviewed on the basis of published reports, interviews with representatives of university departments, and personal observations. Considerable activity exists to promote the theory and practice of management science/operations research in industry, in the public sector, and in several universities.
TL;DR: A comprehensive hyd-scheduling system, HYSS, was developed for the Pacific Gas and Electric Company to produce optimal release policies for each of the 86 hydropower plants in the 23 river-basin hydroelectric system as mentioned in this paper.
Abstract: A comprehensive hydro-scheduling system, HYSS, was developed for the Pacific Gas and Electric Company to produce optimal release policies for each of the 86 hydropower plants in the 23 river-basin hydroelectric system. HYSS has become the basic tool used to operate the utility's complex hydro-generation system efficiently. The use of HYSS has helped increase production of hydropower, resulting in a reduction of revenues required from ratepayers of an estimated $10 million to $45 million each year. Also, the improved schedules for hydropower result directly in better resource planning throughout the company.