• ETRI Journal
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• v.10 no.4
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• pp.146-160
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• 1988

The purpose of the present study is to build a model to determine the structure of long-term quasi-optimal rates of local and toll telephone services. The outline of this study is as follows : Telephone business, providing social goods, is capital-intensive industry which needs huge fixed cost to operate exchanges and telephone networks nationwide. The nature of above industry justifies the market structure of telephone business to be natural monopoly and makes a good reason for government's direct regulation, that is, price regulation. Three is a gap between the present rates and the quasi-optimal ones because some administrative processes intervene in rate making process before execution. On the above diagnostic basis, the present study made an empirical test for the optimality of present rates structure in connection with Ramsey-Boiteux model to maximize the sum of producer's and consumer's surplus and also the current study proposed a qusasi-optimal rates structure for better market performance. From the empirical analysis, we can deduce a policy recommendation the local price should be increased to 47% whereas toll price decreased to 24% in order to improve the net welfare worth of 32.6 billion won.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.1
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• pp.34-41
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• 2004

The chemical heat pump based on the Dehydration/Hydration process with a MgO/$H_2O$ system has been researched. The reactor bed could be expected to store the heat around 200∼37$0^{\circ}C$ by the dehydration reaction and to release the heat around 100∼16$0^{\circ}C$ by the hydration reaction under the heat amplification mode operation. The heat output rate of the heat pump system was evaluated using the experimentally determined parameters. The results show that 6∼50 W/kg of heat output and 0.5∼0.8 of heat recovery ratio are attainable. The heat pump will be applicable for a load leveling in a co-generation system by chemical storage of surplus heat at low heat demand and by supplying heat in the peak load period.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2385-2390
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• 2009

Based on the detailed analysis of output characteristics of PV array and residential load usage pattern, a design method to calculate optimal battery capacity for stand-alone PV generation systems is proposed. And also, according to power flow Actual irradiation and temperature data are analyzed to compose a PV array simulator and also six representative home appliances are electrically modeled for load simulator, along with 24hours usage pattern. The surplus and insufficient power can be calculated from the proposed simulation platform, so that selection of an optimal battery capacity can be possible. The theoretical analysis and design process will be explained, along with informative simulation results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.572-577
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• 1996

Stereolithography is a process used to rapidly produce stereolithographic parts directly from three dimensional CAD models. However, design methodologies necessary to create components to be built by stereolithography are different from those required by conventional machining processes. A case in point is the nescessity of support structures, which are used to support a component during the building the build but are removed once building and curing are complete. Support structures are required to anchor the component to the platform and to prevent sagging or disortion. This paper deals with the specially maintained SupportMap data structure to find some region which need support structures. Interferences between support structures and parts, as well as among support structures are checked and statically stable regions are searched to remove the surplus support structures. Cross shaped tooth profiles are designed for easy eliminating the support structures.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.221-230
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• 1999

Many enterprises are performing the production planning computerization for survival in unlimited competing period. But it is very difficult to directly apply many production planning softwares to the domain-specific areas of many small enterprises because one enterprise is different from the others with respect to product type, production process, and order fulfillment method. Practically most small enterprises depend on experienced production managers in production planning, so then many problems such as overtime work and cost have been appeared. The purpose of this study is to develop production planning module for order-made production system in order to reduce overtime works and surplus costs. We developed production planning module with RDBMS, which is fit for small manufacturing company. Developing this software, we use Visual Basic 5.0 to provide GUI environment for the production planning module and Microsoft Access 97 is used to construct Database. This production planning module is applied to enhancement of productivity in M manufacturing company located in Asan.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.7-17
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• 1998

Stereolithography is a process used to rapidly produce stereolithographic parts directly from three dimensional CAD models. However design methodologies to create components to be built by stereolithography are different from those required by conventional machining processes. As a typical case in point, the support structures are required to support a component at build stage, but are later removed once building and curing are complete. These structures are used to anchor the component to the platform and to prevent sagging or distortion. This paper deals with the Support Map data structure prepared to find the appropriate regions of supports. Interferences between supports and parts, and support structure themselves as well, are checked and thus the system are searching the statically stable regions to remove the surplus support structures. Cross shaped tooth profiles are designed for easy eliminating the support structures.

• Journal of the Korean Regional Science Association
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• v.10 no.2
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• pp.61-71
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• 1994

Despite of being the criteria to choose the efficient and reasonable alternatioves inactual planning process, the measure of accessibility rarely has applied to practices because each model has unexplicity concept of it and limitations in itself. Accessibility implies transportation system which offers opportunity of movement to overcome spatial separation and, simultaneously, land-use system which represents the location of each activity. Therefore, measures of accessibility have to represent the attractiveness of locations and the interactions of activities, that is, land-use and transportation, with an index. Considering that urban activity is based on the economic efficiency, costs and benfits, accessibility means the economic efficiency of the location of activity and the travel in view of land-use and transport repectively. Combined models that measure accessibility with considering land-use and tranportation simultaneously depend on reasonable concepts, but it is too simple for them to explain the accessibility which resulted from complex interaction of urban activities. Combined urban activity model developed by Kim (1983) and Rho (1989) explains the characteristics of activities in each regions and urban strcture in economic general equilibrium states in the long term of urban system. This model measures a regional accessibility with a dual variable which means the location surplus. This is a more systematic and comprehensive model for calculating the regional accessibility because it considers the interaction of each activity in urban system. It needs efforts to apply the accessibility index as a criterion in actual planning process through finding and quantitification of other explanatory variables to measure it in combined urban activity model.

• Journal of the Korean housing association
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• v.11 no.4
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• pp.23-33
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• 2000

Up until the mid-90s, the housing market of Korea has been supplier-oriented with the constant shortage of housing supply. But today, with the surplus of supply over demand and ever-increasing competitiveness in the housing market, understanding consumers needs have become one of the keys to successful business. Consumers overall living standard have increased and they are now looking for better living environment. As a matter of course, there have been much studies focusing on the evaluation factors and consumers preferences of the living environment, somewhat overlooking the asset value of a residential property. Consumers see their house in terms of both a living space and an asset. Therefore, it is these two values altogether that influences the buying decision process of consumers. This study seeks to stress on the importance of the fact that it is both the living environment and asset value of a house that are considered in the buyers valuation of residential property. And the study suggests that influencing factors of housing attributes in the decision-making process of buyers be sub-categorized into two broad groups, value as a living space and value as an asset. This is to serve both the researcher in the academic field and marketers for better understanding of consumers needs and influencing factors of buyers valuation of housings vis-a-vis market.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.61-67
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• 2020

The fourth industrial revolution encourages manufacturing industry to pursue a new paradigm shift to meet customers' diverse demands by managing the production process efficiently. However, it is not easy to manage efficiently a variety of tasks of all the processes including materials management, production management, process control, sales management, and inventory management. Especially, to set up an efficient production schedule and maintain appropriate inventory is crucial for tailored response to customers' needs. This paper deals with the optimized inventory policy in a steel company that produces granule products under supply contracts of three targeted on-time delivery rates. For efficient inventory management, products are classified into three groups A, B and C, and three differentiated production cycles and safety factors are assumed for the targeted on-time delivery rates of the groups. To derive the optimized inventory policy, we experimented eight cases of combined safety stock and data analysis methods in terms of key performance metrics such as mean inventory level and sold-out rate. Through simulation experiments based on real data we find that the proposed optimized inventory policy reduces inventory level by about 9%, and increases surplus production capacity rate, which is usually used for the production of products in Group C, from 43.4% to 46.3%, compared with the existing inventory policy.

• Journal of Society of Preventive Korean Medicine
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• v.24 no.2
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• pp.83-94
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• 2020

Backgrounds : To reduce the patients' economic burden of herbal decoctions use, in 2012, Korean government decided to implement the pilot project of herbal decoctions coverage in the National Health Insurance. Objectives : This study aimed to analyze the policy decision-making process for the pilot insurance project in 2012. Methods : Official documents, research papers, statistical reports, and news articles, etc. on the coverage of herbal decoctions were searched and collected. We used the Kingdon's Policy Stream Model to analyze how the policy of pilot project of herbal decoctions coverage was decided, and who were the main activists for the decision-making process. Results : Components to be included in the 'Problem stream' were the decline in the profits of Korean Medicine institutions, the contraction of the herbal decoctions use, and the fiscal surplus of National Health Insurance. In the 'Policy stream', there were several model studies for herbal decoctions coverage, and examples of herbal benefits in other social insurances. In the 'Political stream', there were the legislative initiatives by member of the National Assembly and the promotion of insurance coverage by the Association of Korean Medicine(AKOM), etc. Policy window for herbal decoctions coverage was opened by the combination of these three streams with the efforts of policy activists, such as the executives of AKOM, and policy researchers. Conclusions : The policy decision process for health insurance coverage of herbal decoctions was analyzed using Kingdon's model, and the analysis shows that the combination of political streams and entrepreneurs' competencies can be an important driving force in policy decision making.