• 산업경영시스템학회지
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• 제17권31호
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• pp.59-72
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• 1994

This paper deals with ordering policies of consumable goods which have large demand rates in a multi-level distribution system. The system we are concerned consists of one Central Distribution Center(CDC) and N non-identical Regional Distribution Centers(RDCs) which have different demand rates, minimum fillrates, leadtimes, etc. The customer demand on the RDC is stationary poisson and the RDCs demand on the CDC is superposition of Q-stage Erlang distributions. We approximate the RDCs and CDC demand distribution to nomal in order to enhance the efficiency of algorithm. The relevant costs include a fixed ordering cost and inventory holding cost, and backorder cost. The objective is to find a continuous-review ordering policy that minimizes the expected average costs under constraints of minimum fill rates of RDCs and maximum allowable mean delay of CDC. We developed an algorithm for determining the optimal ordering policies of the CDC and the RDCs. We verified and compared the performance of the algorithm through the simulation using the algorithm result as the input parameters.

• 보건의료산업학회지
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• 제3권2호
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• pp.1-15
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• 2009

The purpose of this study is to analyze the internal factors that influence the performance of local government hospitals in Korea. There are 34 hospitals in korea as of 2008. Among these hospitals 5 are profit-making and the other loss-making in terms of profitability. Data was collected by Institute of local government hospital union. The major findings of this study was as follows : Firstly, 7 hospitals are high level, over than 100% of fixed ratio. But that result was better than the other study 5 years ago. Secondly, 29 hospitals are bellow 85% of bed occupancy rate. There are a number of hospitals didn't use the facilities and the personnel cost in total costs are high. And lastly, as a result of multiple regression analysis, the factors had on significant effect on normal profit to total assets are personnel cost(-), liability to total assets(-), average length of stay(-), outpatient visits to inpatient days(-). In conclusion, to improve the profitability of hospitals, the efforts to reduce personnel cost and to increase bed occupancy rate.

• Journal of the Korean Statistical Society
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• 제31권4호
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• pp.415-431
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• 2002

A unified framework for statistical inference for the mean of the normal distribution to derive point estimates, confidence intervals and statistical tests is proposed. This optimal design is justified after investigating the basic information and requirements that are possible and impossible to control when specifying practical and statistical requirements. Point estimation is only credible when viewed in the larger context of interval estimation, since the information required for optimal point estimation is unspecifiable. Triple sampling is proposed and justified as a reasonable sampling vehicle to achieve the specifiable requirements within the unified framework.

• 한국철도학회논문집
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• 제9권1호
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• pp.23-28
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• 2006

Many services have been served by the exiting subway systems since they have opened in 1975. But its efficiency and competition were going down because of the high construction cost and difficult connection with other transportations, etc. Otherwise, the light rail transit system is much lower construction cost than the subway and the high way building. Also those systems are good at the inexpensive operation cost, the fixed time and safety, the easy access. Recently, the several provinces are planning or advancing the light rail transit system because of these many benefits. Consequently, those system's economical feasibility analysis is required rapidly to show the resonable construction's cause and to get the private investment. This paper offers the system's economical feasibility through the several benefit analysis after the light rail transit system's construction.

• 통상정보연구
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• 제14권3호
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• pp.31-47
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• 2012

1999년 유로존(Eurozone)은 단일통화 출현을 목표로 출범하였다. 유로화(Euro)의 사용은 회원국들에게 있어 GDP의 약 1%에 이르는 환전비용과 환위험 관리비용을 제거하였다. 또한 안정적인 역내 물가수준을 유지할 수 있었고 저금리 기조를 유지하며 투자와 고용의 촉진이 이루어졌다. 유로화의 국제적 위상에서도 세계 외환보유고 비중이 2010년 기준 26.9%로 제2위의 기축통화국으로 자리매김하였다. 역내 회원국들 간에도 환율 고정에 따른 환율 위험을 떨어드려 투자와 경제성장을 유도하였다. 특히나 금융시장에서는 거래비용의 감소로 유로화의 수요가 증가하였고 교역에서도 대금지급수단으로 유로화가 사용됨으로써 교역증가로 인한 단일시장 효과를 유발하고 있다. 본 연구에서는 EU내 단일통화 사용이 회원국들 간의 수출과 수입에 미치는 파급효과에 대해 임의효과모형(random effect estimation)과 고정효과모형(fixed effect estimation)으로 분석해 보았다.

• 한국콘텐츠학회논문지
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• 제18권9호
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• pp.44-54
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• 2018

건설사업을 수행함에 있어 설계분야는 최종 성과물의 성패에 결정적인 영향을 미칠 뿐만 아니라 기술집약적 고부가가치를 창출하기 때문에 국가 산업발전의 핵심영역으로 그 중요성이 점차 부각되고 있다. 또한, 설계업무는 전문기술인력을 기반으로 수행되므로 설계의 품질 및 경쟁력을 확보하기 위해서는 지속적인 우수인력의 유입과 기술개발이 필요하며, 무엇보다도 적정 수준의 설계 대가 확보가 수반되어야할 것이다. 그러나 대표적인 건설설계 분야에 해당하는 도로공사 실시설계에 대하여 국내 대가기준의 현황을 검토한 결과, 대가 산정방식의 혼재, 공사비요율방식의 부정확성, 실비정액가산방식의 비활성화 등과 같은 문제점이 분석되었고, 이로 인하여 대가 산정 시 사업의 특성을 반영한 적정 대가의 산출이 어려운 것으로 파악되었다. 따라서 해당사업의 과업내용에 따라 설계의 적정대가를 책정할 수 있도록 대가기준이 개선되어야 할 것이며, 본 연구는 이러한 개선방안 마련의 일환으로 실제 수행 완료된 도로공사 실시설계의 사업 및 대가 정보를 수집하여 상관분석 및 다중회귀분석을 실시함으로써 도로공사 실시설계 대가의 영향요인을 도출하고 영향수준을 분석하였다.

• 전기학회논문지
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• 제67권2호
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• pp.179-185
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• 2018

A considerable cost gap between three major power generation technologies, namely nuclear, coal, and combined cycle gas turbine (CCGT), has been a well-established fact in the Korean electricity market. Alternatively, this paper analyzes the levelized costs of electricity (LCOE) of the three technologies reflecting overall social costs of electricity generation including accident risk, $CO_2$ emission, and air pollution damage. The paper unveils to what extent current discriminative subsidies on fuels regarding the social costs, mostly through tax exemptions, affect economic competitiveness of the technologies. In particular, it finds relative positions of coal and CCGT could be altered depending on appreciation level of the social costs. It has limits in analyzing fixed costs of the technologies, however, due to limited data availability of nuclear power, and suggests further studies on the issue.

• 한국항해항만학회지
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• 제38권6호
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• pp.567-575
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• 2014

In recent times, an obvious strategy in liner shipping markets that has come to the fore is slow steaming. Nowadays, most liner shipping companies have decelerated the voyage speed to 15-18 knots on major routes, and some leading liner shipping companies have a plan to reduce it to below 15 knots. Slow steaming is helpful in reducing the operating cost and the amount of greenhouse-gas emissions on a single vessel with lower fuel consumption. However, it also creates various negative effects such as the opportunity cost, additional fixed costs and an in-transit inventory cost on a loop. Hence, the net operating cost on a loop is changing dynamically due to the changes of voyage speed based on various slow steaming effects. The aim of this study is to analyze the slow steaming effects in the liner shipping, and to find the best voyage speed that minimizes the operating cost on a loop. Moreover, this study suggests the recommendable strategy for liner shipping companies. To achieve the aim of this study, a simulation model has been designed using System Dynamics.

• 한국IT서비스학회지
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• 제16권2호
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• pp.45-60
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• 2017

The study suggests a contract model of application operation through case study of A bank's IT outsourcing application contract based on workload. The IT outsourcing order form has a problem in that the scope of work is ambiguous due to the integration of operation and maintenance. In this study, application operation and maintenance were separated by referring to application operation history provided in ISO/IEC15504-5 standard. The scope of the IT outsourcing service was clarified by organizing the definition and detail activities of the application operation business. Application operation contract method has generally applied estimation method by the number of input manpower and period by agreement between buyer and client. As there is no activity to calculate the number of input manpower based on the operational work history and based on the standard workload per activity. In this case is not guaranteed due to the simple agreement between the contractors. In this paper, we propose an application operating cost estimation model that measures the size of the operating software using function point analysis that is the basis of application operation tasks. In order to verify the validity of the application operation cost model, we verified the correlation between the application size and the labor cost through regression analysis using SPSS.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.67-74
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• 1979

This survey was carried out to grasp the actual condition of a power tiller utilization . Now, the power tiller has become the leading machinery in the field of agriculture throughout the country . Two hundred farm houses, located in the provincial districts of Kimcheon and kum0rung, hav etaken part in the survey from October 1, 1976 to September 30, 1977. The results are summarized as follows . 1. The average size of cultivated land of a farm household in the districts surveyed was 1.77ha which was bigger than that of whole country. And the average age of power tiller drivers was analyzed in which only 105 of total drivers was on their 30's. 2. Distribution of a power tiller utilization was appeared to be 34.4% for transporting , 24% for tilling , 23% for pumping , 11.5% for threshing and 6.6% for spraying. 3. Frequency of a power tiller utilization was high during the month of June, July and October while it was low during February and December . 4. Distribution of repairing cost was 8.5% for trailer, 7.1% for throttle lever and 6.7% for casket, respectively. The annual cost for repairing was 5,290 won.5. The annual cost for using a power tiller was composed of 51.5% of fixed cost and 48.5% of operating cost. 6. Economic analysis showed that it was not economically practical for individual ownership of a power tiller on the farm surveyed. Therefore, custom operation and joint ownership by a few farmers were recommended.