We consider a problem of estimating the economics of scale for the natural gas industries. The goal programming/constrained regression is employed for estimating the economics of scale for the natural gas industry, and the problem is formulated as a linear programing problem. Also the translog cost function is used to represent the cost structure for the natural gas industry. The Korean Gas Corporation was selected as a case study, and we demonstrate that the suggested goal programming/constrained regression approach is appropriate for estimating the economies of scale for the Korean nature gas industry.

This paper presents the better efficient evaluation of the Small and Medium Enterprises by use of fuzzy multi-criteria decision making methodology under intersectional dependence relations. The five Small and Medium Enterprises alternative will be evaluated by Fuzzy Analytic Hierarchy Process(FAHP) based on entropy weight in this study. A case study is presented to illustrate the use of entropy weight measurement with intersectional dependence problems. These problems are evaluated seven criteria : market criteria, thchnology criteria, management ability criteria, planning criteria, propulsion ability criteria, project propulsion basis criteria, propulsion result criteria.

The Generalized Assignment Problem(GAP) determines the minimum assignment of n tasks to m workstations such that each task is assigned to exactly one workstation, subject to the capacity of a workstation. In this paper, we presented a new heuristic search algorithm for GAPs. then we tested it on 4 different benchmark sample sets of random problems generated according to uniform distribution on a microcomputer.

Generally, the standard sizes of military combat fatigues should be determined by considering the coverage rate in order to minimize the military personnel who can't put on the ready made military combat fatigues. The coverage rate should be increased by the longer interval of the standard size but the satisfactory rate will be decreased due to the longer interval of size. This study develops a method selecting optimal standard sizes of the military combat fatigues in order to maximize the satisfactory rate that insures the coverage rate to meet a given level for ready made military combat fatigues. This method selects candidate standard sizes at second and finally, establishes a 0-1 inter programming model. The result shows that the method increases both coverage and satisfactory rate more than those of the previous method.

The most research on facility layout problems ignored the actual shapes of activity spaces and the aisles between activities. In many cases, the research also ignored the actual shape of building where the activities are to be arranged. In this paper, We present a block based layout technique that applies a genetic algorithm to search for a very good facility layout with horizontal aisles. From the extensive experiments for two different cases with respect to the shape of activity space, it was found that the proposed method generated better layouts than the ones obtained by applying Tam's algorithm in all test problems. The proposed algorithm showed about 10% improvement of performance on the average. We determined the best combination of the reproduction rule and the genetic operators with their probabilities for each test problem through the experiment.

This paper proposes an approach for individual selection in genetic algorithms to improve problem solving efficiency and effectiveness. To investigate the utility of combining simulated annealing with genetic algorithm, two experiment are conducted that compare both the conventional genetic algorithm and suggested approach. Result indicated that suggested approach significantly reduced the required time to find optimal solution in moderate-sized problems under the conditions studied. It is also found that quality of the solutions generated by suggested approach in large- sized problems is greatly improved.

There have been lots of research on temporal data management for the past two decades. Most of them are based on some logical data model, especially on the relational data model, although there are some conceptual data models which are independent of logical data models. Also, many properties or issues regarding temporal data models and temporal query languages have been studied. But some of them were shown to be incompatible, which means there could not be a complete temporal data model, satisfying all the desired properties at the same time. Many modeling issues discussed in the papers, do not have to be done so, if they take object-oriented data model as a base model. Therefore, this paper proposes a temporal data model, which is based on the object-oriented data model, mainly discussing the most essential issues that are common to many temporal data models. Our new temporal data model and query language will be illustrated with a small database, created by a set of sample transaction.

Demand for new information services is ever increasing as information technology advances in an unprecedented pace. Capabilities of information technology to overcome the time and space limitations enables efficient storage and processing of a large volume of data shared by many users in geographically dispersed areas. As the users ask for more useful information services, it is necessary to develop information services tp meet the needs of users. Enhancing information services is also necessary to cope actively with the pressures to open the information service is also necessary to cope actively with the pressures to open the information and telecommunications market as the level of Korean information services industry is still in its infancy. Value Added Network(VAN) services have a tremendous growth potential and its economic and social impact would be great as the information society matures. This study suggests a direction for the development of value added and new-media services based on the survey of individual and business users of information services.

Software cost estimation is an important both for buyers and sellers(developers). We reviewed domestic and foreign researches and practices on software cost estimation with function point method comprehensively, In this paper, we derived four promising alternative function point models. They are an IFPUG(International Function Point User Group)-based model(Model I), a shorthand model for client/sever software systems(Model II), a data-oricnted model for relatively large software projects(Model III), and a general- purpose function point model for non business application softwares as well as business applications(Model IV). Empirical data shows that Model I, II, and IV are very useful function point models. In particular, model II and IV look very useful models since they are concise and accurate. These models can be incorporated in a new improved guideline for software cost estimation. General opinion survey shows that Model I, II and IV are preferable. There are no significant differences in preference between buyers and sellers. The survey also shows that users think function point method is better than step(line of code)-oriented cost estimation methods in many ways including objectivity and estimation accuracy.

This study addresses strategic issues related to the question of" how can a supply chain become more competivity\ulcorner" We examine several cases of manufacturing supply chains. Results show that each constituent firm is required to maintain different manufacturing capabilities and to play different roles by its position (up/mid/down-stream) in a chain. Furthermore, there are patterns of required capabilities by the positions in a chain. These findings imply that the "position in a chain" should be treated as one of the strategic factors when discussing the buyer-seller relationship. It is also shown that different action programs are required for building different manufacturing capabilities of individual firms in a supply chain. Additionally, we argue that some programs need to be done simultaneously, by all the members of the chain, while some need to be carried out by only a small group or an individual firm. Finally, we propose a direction for a theoretical framework for analyzing supply chain structures and strategies.ures and strategies.

This study concerns performance evaluation of the research-funding agencies focused on Korea Science and Engineering Foundation(KOSEF). On the basis of the constituents approach and the systems approach of organizational effectiveness theory, the evaluation items are derived reflecting generic characteristics of the research-funding agencies, and their priorities are determined using analytic hierarchy process(AHP). Three groups of constituents with differing interest and expections are identified, and their perceptions on the importance of the evaluation items are measured through questionnaire survey. Analyses show that the evaluation items perceived important by each constituency are significant different from one another. The implications of the result to the Government and KOSEF are discussed.

Higher level representation splay an important role in model management systems. The role is to make decision makers friendly represent their problem using the representations. In this research, we address higher level representations including five distinctivenesses: Objective, Node, Link, Topological Constraint including five components, and Decision, Therefore, it is developed a system called HLRNET that implements the building procedure of network models using structural knowledge and object data The paper particularly elaborates all components included in each of distinctiveness extracted from structural characteristics of a lot of telecommunication network models. Higher level representations represented with five destinctivenesses should be converted into base level representations which are employed for semantic representations of linear and integer programming problems in a knowledge-assisted optimization modeling system. The system is illustrated with an example of the local access network model.