• 한국항만학회지
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• 제9권2호
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• pp.39-49
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• 1995

Recently, the traffic volume has been greatly increased partly because of high growth rate of domestic and world economy, and partly because of increased transhipment demand resulting from the destruction of Kobe port by earthqwake early this year. So, container facilities in Pusan Port are under serious congestion. The congestion costs in connection with container traffic in Pusan Port is estimated to be 29.3 billion won in 1994. In 1995 the situation is still worsening. PECT has continued to grow annually by 35% in cargo handling exceeding more than 31% of the total container volumes handled in Korea. The BOR of container berths in PECT in 1994 is 75% reflecting extreme congestion in container traffic. The reason for such serious congestion in PECT is the shortage of container handling facilities in comparison with ever-increasing cargo traffic. In order to solve the provisional problem, the shortage of handling capacity, a model developed to optimize the operation of PECT is described and demonstrated. The model minimizes total port costs, including the costs of dock labour, facilities and equipment, ship, containers, and cargo. The object of this study is, through the model results, mainly to determine the optimal combination of berths and cranes under various circumstances and to show that total costs per ship or unit of cargo served can be reduced by increasing the number of cranes per berth and berth utilization above present levels. Eventually, the results obtained with this model in PECT suggest that increase to 3 in the number of cranes per existing berth could reduce the need for major investments in berths and even reduce operating costs.

• 산학경영연구
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• 제19권1호
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• pp.25-34
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• 2006

직접시공이나 하도급시공은 건설산업기본법에 의해 정한 시행령에 따라 시공하는 것이 원칙이나 직접시공이나 하도급시공시 수익성을 비교하여 이익 창출을 극대화하는 방향으로 의사결정이 된다. 이 연구에서는 민간공사 사례를 바탕으로 직접시공과 하도급시공의 공사원가와 수익성을 비교분석하였다. 자료 수집은 S건설에서 2002년과 2003년에 공사한 근린생활 및 단독주택을 토대로 하였다. 공사건수의 사례는 직접시공과 하도급시공 각각 3건의 공사에 의한 평균비율 값에 의하여 비교분석하였다. 이 연구의 사례를 분석한 결과, 공급가액 대비 매출총이익에 대한 수익률은 하도급시공이 직접시공 보다 1.3% 높은 수익률을 올린 것으로 분석되었다. 영업이익에 대한 수익률은 하도급시공이 직접시공보다 2.3% 높은 수익률을 올린 것으로 분석되었다. 마지막으로 하도급시공(영업이익률 11.7%)이 직접시공 공사에 대해 4대 보험료 차감후의 최종 영업 이익률이 4.4% 더 많이 발생한 것으로 분석되었다. 그러므로 건설회사는 하도급을 주는 것이 수익률이 높다는 것을 알 수 있고, 노무자 관리 또한 용이한 것으로 나타났다.

• 한국컴퓨터정보학회논문지
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• 제23권8호
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• pp.133-142
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• 2018

Subway metro scheduling is one of the most important problems impacting passenger convenience today. To operate efficiently, the Seoul metro uses regular, periodic schedules for all lanes, both north and southbound. However, many past studies suggest that non-periodic scheduling would better optimize costs. Since the Seoul metro is continuously facing a deficit, adopting a non-periodic schedule may be necessary. Two objectives are presented; the first, to minimize the average passengers' waiting time, and the second, to minimize total costs, the sum of the passenger waiting time, and the operational costs. In this paper, we use passenger smart card data and a precise estimation of transfer times. To find the optimal time-table, a genetic algorithm is used to find the best solution for both objectives. Using Python 3.5 for the analysis, for the first objective, we are able to reduce the average waiting time, even when there are fewer trains. For the second objective, we are able to save about 4.5 thousand USD with six fewer trains.

• Industrial Engineering and Management Systems
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• 제8권4호
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• pp.221-227
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• 2009

There are customer services jointly provided by two facilities so that each customer will complete the course made up of both facilities' sub-services. The two facilities are assumed invested respectively by an infrastructure owner and one subordinate facility owner, whose partnership is built on their capital investments. This paper presents a mathematical model of Stackelberg competition between the two facility owners to derive their optimal Nash equilibrium. In this study, each facility owner's profit is consisted of fixed revenue fractions of sold services, operating costs (including depreciation cost) and maintenance costs of her facility. The maintenance costs of one facility are incurred both by failures and deterioration due to usage. Moreover, for both facilities, failures are rectified immediately by minimal repairs and preventive maintenance is carried out at a fixed time epoch. Additional assumptions are also employed to develop the model such as customer arrivals are manipulated to follow a Poisson process, and each facility's lifetime is independently Weibull-distributed. The Stackelberg game proceeds as follows. At the first stage of decision making process, the infrastructure owner (acting as a leader) decides the allocation of revenue shares based on her self-interest. After observing the allocation of revenue shares, the subordinate facility owner determines her own optimal price of services. This paper investigates actions and reactions of the two partners in the system. Then analytical conditions are proposed to achieve a unique optimal Nash equilibrium. Finally, some suggestions for further research are discussed.

• 가정∙방문간호학회지
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• 제19권2호
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• pp.119-126
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• 2012

Purpose: The purpose of this study is to identify clubhouses general characteristics, core services, funding sources and costs in Korean Clubhouse Model, and to compare with Korean and international clubhouses. We explored the annual budget, cost per member, and cost per visit for 1 year. Methods: The data were collected from 14 Korean clubhouses and analyzed using descriptive statistics and Spearman's rank correlation with the SPSS 14.0 program. Results: The average of clubhouse operating period was 8.2 years. There were an average of 40.4 active members; among them, 84.1% were schizophrenia. In addition, there were an average of 5.8 staff and 15.3 services in each clubhouse. Cost estimates were as follows: annual budget (excluding housing) $223.633, cost per member $5,704, and cost per visit $21.35. There were significant difference among the annual budget, number of staff, number of service, and active members, but hours of Work-Ordered Day and social activities hours were not statistically significant. Conclusion: Findings provide a more understanding of operations, programs, and costs of Korean clubhouses.

• 드라이브 ㆍ 컨트롤
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• 제9권4호
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• pp.19-25
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• 2012

This paper explains how eliminating contamination from the manufacturing processes will lead to better product quality and hence the need for reworking, a trouble free commissioning period and greatly improved production efficiency. All of these will reduce costs and energy usage. It will also ensure that the product is delivered to the customer in a condition that will ensure improved reliability and longer life, again reducing both energy and other operating costs. Correctly designing the contamination control measures will achieve and maintain the level of fluid cleanliness that is required by the end user. The filter is critical to cleanliness management and should be selected with the same degree of thought and consideration as for other major components. This paper explains the role that Cleanliness Management plays in the reducing the carbon footprint of systems and processes by making them perform more efficiently for longer periods. It also examines two differing ways of selecting filters to incorporate the features of newer designs, and shows how significant savings in the costs of ownership can be achieved using these approaches.

• 수산해양교육연구
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• 제28권6호
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• pp.1629-1639
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• 2016

This study is to estimate the production efficiency of abalone aquaculture and to find its determinants utilizing the survey data of operating expenses in 2015. The first part of the analysis applied both DEA and Super-DEA for the estimation of efficiency of each aquaculture household as DMU. We used wages, feeding costs and area as inputs and annual profits and sales as outputs of the model. The second part of the study applied both Tobit and OLS for the identification of determinants of the efficiency. We investigated cost-ratio, depreciation costs, careers, value of living seeds, cleaning costs of farming ground and a ratio of 1 and 2 year-old abalone at shipment as potential determinants. The estimation results show us that the average technical efficiency, pure technical efficiency, and scale efficiency score turn out to be 72%, 81% and 85% respectively. The Super-BCC and Super-CCR models reveal their average efficiency scores as 81% and 80%. All of the variables used to identify the determinants of the efficiency. The study results suggests that the production efficiency can be improved by cleaning farming ground and hence lowering the death rate of seeds.

• 전기학회논문지
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• 제61권9호
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.624-631
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• 2022

Highway Rest Areas are envisioned to provide an accessible space for rest and parking for travelers, especially those driving a long distance. In addition, modern highway Rest Areas provide many amenities to highway users, including wifi service, picnic tables, litter barrels, running water, public telephones, and sometimes even free coffee. Various studies were conducted in the domain of Rest Area facility design and their operating costs in different states; however, limited studies were conducted on the maintenance costs of these facilities. Therefore, this study's main objective is to compute the annual maintenance cost of Rest Areas in the state of Nevada. This study also analyzes the main cost categories of the maintenance works. The raw cost data of Nevada Rest Area maintenance from 1990 to 2012 were collected from the Nevada Department of Transportation (NDOT). Results show that the maintenance cost fluctuated over the study period; the maintenance cost decreased from 1991 to 2004 and then increased until 2012. The primary cost categories of maintenance work are labor, equipment, and material costs. Among these, labor cost was the largest category with 56 percent of the total maintenance cost, followed by equipment cost and material cost. The findings of this study may help NDOT and other transportation agencies plan their budget for future Rest Area maintenance activities.

• 농촌지도와개발
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• 제16권4호
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• pp.913-938
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• 2009

This study attempts to develop a framework to analyze and estimate various effects of agro-product e-commerce, and to find out the actual effects of the farmers operating on-line shopping systems through the developed framework. A depth-interview semi-structured on 5 farmers was acted to seek out latent effects which were disassembled and re-assembled into 3 dimensions; input costs, e-internal effects and e-external effects. E-external effects divide into e-indirect effects and e-societal effects. A survey from 29 farmers reveals that the e-internal effects are 26,929 thousand KRW a year, e-external effects 6,734 thousand KRW, and input costs 7,202 thousand KRW. ROI(Return on Investment) in 2007 is calculated at 367%.