• Korean Management Science Review
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• v.13 no.3
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• pp.37-48
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• 1996

This paper presents an Economic Lot Scheduling Problem in which controllable production rates are considered. We also take into account the controllable range of production rate (i.e., maximum and minimum production rate) of each product and the mold cost which varies to the production rate. A mathematical model is developed and an iterative solution procedure is suggested. The objective of this problem is to minimize production related cost and the decision variables are common production cycle time and production rate of each product. As a case study, we adapted this model to the press machine of a company.

• KDI Journal of Economic Policy
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• v.40 no.2
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• pp.53-73
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• 2018

Using an overlapping generations model, this paper examines tax policy effects across generations. The model incorporates housing assets separately from capital assets and includes taxes on labor income, capital income, consumption and housing assets. Tax reforms for each tax rate have different effects on tax burdens across generations and the overall efficiency of the economy, leading to different welfare costs for generations. Specifically, raising housing property taxes results in the smallest welfare loss by future generations, as in the model it does not hurt economic efficiency and the tax burden increases mainly for the elderly, who have accumulated housing assets in preparation for retirement.

• Journal of the Korean Regional Science Association
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• v.40 no.3
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• pp.109-126
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• 2024

The central government has been promoting innovation cities since the early 2000s for the balanced development of the country in order to solve the problems of overcrowding in the metropolitan area and underdevelopment of the country due to rapid urbanization since the 1980s. The 10 innovation cities built through the regional relocation of public institutions were expected to have positive effects such as economic revitalization and population influx, but uncertainties and various externalities still exist. Therefore, this study aims to analyze innovation cities from the perspective of urban resilience to create sustainable cities. To this end, the research analyzed urban factors in the physical, natural, social, economic, and institutional dimensions of Ulsan Ujeong Innovation City, and applied the Adaptive Cycle and Panarchy to comprehensively analyze them. As a result of the analysis, it was found that the built, socio-economic, and natural environments are currently undergoing the adaptive cycle stages of preservation, reorganization, and growth, respectively, and the interaction and structural causal relationships between Korea, Ulsan Metropolitan City, and Ulsan Ujeong Innovation City were identified. The study concluded that Ulsan Ujeong Innovation City can be sustainable by utilizing opportunities such as the central government's Innovation City Season 2 and financial support, construction of Janghyeon Advanced Industrial Complex, and fostering local innovation clusters according to local conditions.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.103-112
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• 2017

PURPOSES : In this study, field performance evaluation of crack treatment of pavement and the feasibility of surface treatment of pavement are presented. The performance and cost of preventive maintenance methods have been previously verified, and the methods are being used in many developed countries and cities. However, the performance and cost of the system have not been verified in domestic, field applications. Therefore, in order to improve performance, the field performance is evaluated, and a reasonable cost is proposed. METHODS : Visual Inspection was conducted to evaluate the field application and performance of the preventive maintenance method. In addition, the PCI index was calculated from the results of visual inspection of the application area of the surface treatment method, and the performance life of each method was predicted. For the economic evaluation, life cycle cost analysis was performed using the life cycle cost analysis program. RESULTS :In order to evaluate and quantify the field performance of crack repair material, the residue condition of the pavement surface after crack treatment, rather than the performance of the material, is evaluated. In addition, the crack resistance and performance life of surface treatment methods are evaluated. The cost of currently available treatment methods are compared to the common pavement cut and overlay method, and it is determined that the preventive method is not economical based on life cycle cost analysis. CONCLUSIONS :Because of the characteristics of cracking, it is necessary to conduct the evaluation of currently applied methods and the analysis of the cause of damage, by visual inspection. Moreover, in order to evaluate the performance and economic suitability of the currently applied surface treatment methods, it is necessary to acquire information on application sections by monitoring their long-term conditions and performance.

• Economic and Environmental Geology
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• v.4 no.2
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• pp.77-90
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• 1971

About four hundred deposits of iron, talc, fluorite, tungsten, molybdenum, lead, zinc and other polymetallic mineral deposits were plotted on the Ore Distribution Map of the Ockcheon Geosynclinal Area. These mineral deposits plotted on the map can be divided into the several metallogenic zones by the consideration of their geologic background including the sedimentary and tectonic cycles and the igneous activities in the geosynclinal evolution, as follows: a. Chungju iron and talc zones. b. Cheong-san copper bearing iron sulphide zone c. Kumsan-Muju fluorite-polymetallic zones. d. Cheong-an Puyong and Ein Suckseong gold zone e. Hwang-gan Seolcheon and Sangju gold zones. Chungju iron zone originated in the iron bed in the Kemyongsan Series corresponding to the Pre-Ockcheon Cycle of evolution history. In early period of the Ockcheon Cycle, Hyangsanri quartzite and Munjuri phyllitic formation corresponding to the lower terrigenous sequence were not mineralized while the next sequence of the Samsungsan basic igneous-metamorphic formation and the Changri limestone formation were mineralized by the copper bearing iron sulphide and the fluorite-polymetallic deposits respectively. Two generations of the gold zones are recognized. The earlier generation distributes directionaly in the outside of the Ockcheon sedimentary belt was followed by the earlier grantitic invasion of Jurasic in age, while the later generation scatters at random which was related to the nondirectional Cretaceous granitic intrusion of the Post-Ockcheon Cycle. Conclusively speaking, it was disclosed that the endogenic mineralization in the Ockcheon geosyn clinal zone was not conspicuous in its inner sedimentary belt except its limestone area but in its outer peripheral granitic or gneissic zones, and the related igneous activities occured in the Post-Ockcheon Cycle of evolution history.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1303-1314
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• 2016

This work examines the most viable nuclear technology options for future underwater designs that would meet high safety standards as well as good economic potential, for construction in the 2030-2040 timeframe. The top five concepts selected from a survey of 13 nuclear technologies were compared to a small modular pressurized water reactor (PWR) designed with a conventional layout. In order of smallest to largest primary system size where the reactor and all safety systems are contained, the top five designs were: (1) a lead-bismuth fast reactor based on the Russian SVBR-100; (2) a novel organic cooled reactor; (3) an innovative superheated water reactor; (4) a boiling water reactor based on Toshiba's LSBWR; and (5) an integral PWR featuring compact steam generators. A similar study on potential attractive power cycles was also performed. A condensing and recompression supercritical $CO_2$ cycle and a compact steam Rankine cycle were designed. It was found that the hull size required by the reactor, safety systems and power cycle can be significantly reduced (50-80%) with the top five designs compared to the conventional PWR. Based on the qualitative economic consideration, the organic cooled reactor and boiling water reactor designs are expected to be the most cost effective options.

• Economic Analysis
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• v.26 no.2
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• pp.43-71
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• 2020

This paper aims to derive macroeconomic implications by analyzing the business cycle characteristics of the youth unemployment. The results of empirical analysis seem to show that youth unemployment appears to be relatively less correlated with business cycle compared to other age groups, and thus it is difficult to explain the recent steady increase in the potential labor force as a result of the business cycle fluctuation alone. Moreover, the alternative unemployment measures of the youth group showing upward trend were estimated to be co-integrated with output measures. This co-integrated trend increase suggests that unlike other age groups, youth may be influenced by structural factors inherent in Korea's economic growth path. The fact that the wage difference based on firm size has widened steadily since the Asian financial crisis and that the proportion of large companies that provide relatively high-quality jobs compared to major industrialized countries is significantly lower may be the evidence of the structural changes in Korean youth labor market. The results of above analysis may explain why the job search periods for youth has lengthened amid these structural changes.

• Journal of the Korea Society for Simulation
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• v.13 no.2
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• pp.35-43
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• 2004

The purpose of this study is an economic analysis of power plant utilities by comparing electricity generating cost including environmental costs. Considering the enormous role of electricity in the national economy, it is very important to study the effect of environmental regulation on the electricity sector. Because power utilities need for large investment during construction, operation and maintenance, and also require much construction lead time. Economic analysis is the important process in the electric system expansion planning. This paper compares the costs of electricity generation including environmental costs between a coal-fired power plant and an LNG combined cycle power plants. With the simulation, this study surveys the sensitivity of fuel prices, interest rate and carbon tax. In each case, this sensitivity can help to decide which utility is economically better in environmental regulation circumstance.

• IE interfaces
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• v.6 no.2
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• pp.37-51
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• 1993

This paper studies the economic replacement method for production facilities which requires huge investment but are necessary for higher productivity and competability of products. That is, the general models for the decision of economic life of properties which minimizes the total costs throughout the usage life(Life cycle costs) are generated. Main factors which make influences for the decision of econmic life can be divided by three. These are the change of salvage value, repair and maintenance costs, and availability of production facilities with the passage of usage time. In this paper, the real world data for these three factors are collected and analyzed for the extraction of representative standard forms with the passage of time. And general models for economic replacement methods and optimal usage terms are presented through tables with the combination of the standard forms of these three main factors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.950-956
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• 2012

As development of battery technologies, the installation of Battery Energy Storage System (BESS) increased. The BESS can be used for various purposes such like frequency response, load leveling, and fluctuation mitigation of renewable energy generators. In this paper, three state BESS model is proposed. the BESS model considering charge, discharge and keeping efficiency, and life cycle according to depth of discharge (DOD). Then, the benefit and cost of BESS installed at substation for load leveling are summarized. The economic evaluation of BESS is analyzed using net present values (NPV) analysis. In case study, the NPV analysis of NaS battery system is carried out using the proposed BESS model. Because the result of economic evaluation of BESS using nowadays cost data is not positive, the sensitivity analysis of BESS is conducted by changing the capital cost and energy cost.