• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2002년도 춘계 국제 학술대회
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• pp.54-64
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• 2002

This study evaluated advanced water treatment (AWT) system in Korea. There are currently 16 plants operating with AWT. However, no attempt has been made to evaluate AWT system. This study selected one water treatment plant with AWT (pre-ozonation ＋ BAC). Using the operation data from 1995 to 2001 and pilot study results, the post-evaluation of the AWT system has been conducted. The study found that AWT improved water qualities of organic, ammonia, and turbidity, as expected. However, the extent of the improvement was generally short of the pilot study expectations. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction, Both operation of pre-ozonation and reduced ammonia loading were responsible for the reduction. AWT increased the operation cost. Maintenance, raw water, and power cost increased, while labor and chemical cost decreased. Manpower reduction resulting form automation caused the decrease of labor cost. The reduction of chlorine consumption caused the decrease of chemical cost.

• 전기학회논문지
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• 제65권6호
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• 산업경영시스템학회지
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• 제31권2호
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• pp.19-27
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• 2008

This paper addresses determining the location of the distribution centers in a discrete dynamic distribution system. In discrete and finite time horizon, the demands of retailers are dynamic for the periods. Some locations among the retailers can be chosen for the role of the distribution centers at the beginning of each period. The distribution centers have to be located at the location of minimizing logistics cost. Logistics cost factors are the operation cost and the fixed cost of distribution center, and the transportation cost. The distribution centers of minimizing sum of operation cost, fixed cost and transportation cost are determined among retailers in each period for the planning period. A mathematical model was formulated and a dynamic programming based algorithm was developed. A numerical example was shown to explain our problem.

• 상하수도학회지
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• 제14권1호
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• pp.45-53
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• 2000

The optimum operation of domestic wastewater treatment plant can give influence on operational cost and future expansion in Korea where has 93 operational domestic wastewater treatment plants. Also, the study on optimum operation can reduce operation cost and budget of municipalities whom have responsibility of wastewater treatment plant operation. In this study, 9 domestic wastewater treatment plants which can represent 93 plants in Korea have been selected and operational data are gathered. The collected data are inputted to computer simulator based on IAWQ's Activated Sludge Model No.1 and optimum operation methods are developed. Also, the electric power for aeration which has large portion of overall operation cost are calculated based on design and operation conditions and these are compared. In this study, it was found that design wastewater characteristics are 1.6 times higher than those of daily maximum except for E plant and that estimation methods for design wastewater characteristics have to be improved. Based on computer simulation, we found there is no need to operate all aeration tanks due to weak influent overall power for aeration can be reduced to about 43% of design one.

• 한국산림과학회지
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• 제104권4호
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• pp.615-621
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• 2015

본 연구는 산림작업이 지속적으로 이루어진 5개 지방청 8개 경영계획구를 대상으로 조림 및 숲가꾸기 작업에서 임도시설 전 후의 접근성과 산림작업비용의 절감효과를 분석하였다. 분석 결과, 임도 및 공도로부터 500 m 이내의 사업실행 면적이 임도 시설 전 평균 28.5%에서 임도 시설 후 평균 90.3%로 약 3.2배 증가하였으며, 임도 시설에 따른 조림 및 숲가꾸기 작업에서의 산림작업비용 절감효과는 평균 576천원/km/년인 것으로 나타났다. 따라서 임도시설이 원활한 산림작업을 위한 접근성 개선 및 작업비용 절감효과가 있는 것으로 나타났으며, 임도의 시설효과 분석을 통해 임도 확충 정책의 추진을 위한 기초자료의 제공이 가능할 것으로 판단된다.

• 한국치위생학회지
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• 제20권5호
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• pp.707-716
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• 2020

Objectives: This study aims to provide basic data for high-quality dental services. In addition, we will promote the operation of preventive dentistry that implements preventive measures. It was conducted to study the change of patient's treatment behavior and treatment cost due to the discontinuation of preventive dentistry in university dental hospitals. Methods: This study collected data using the integrated medical information system of the C University Dental Hospital. From September 1, 2017 to August 31, 2019, data were analyzed using frequency, percentage, mean, standard deviation, chi-square test using SPSS version 24.0 statistical program, and T-test. Results: There was a significant difference in the number of preventive dental treatment cases from 58.3% of preventive dental operation periods to 41.7% of preventive dental operation periods. As a result of comparing the medical expenses, the total medical expenses during the preventive dental operation period decreased from 521,308,872 won to 379,724,995 won during the discontinuation period, 141,583,877 won. The number of medical treatments by treatment behavior decreased 3,835 (28.4%) from a total of 13,520 preventive dental operation periods to 9,685. Conclusions: This study is meaningful as the first study to confirm the change in the treatment behavior and the change in the cost of treatment due to the discontinuation of the operation of preventive dentistry at university dental hospitals. In conclusion, it is thought that there is a possibility of the lack of accessibility and the limitation of professional preventive care due to the discontinuation of preventive dentistry.

• 한국경영과학회지
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• 제26권1호
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• pp.71-85
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• 2001

This paper considers a cost model for a U-shaped manufacturing cell formation which incorporates a required number of machines and various material flows together under multi-part multi-cell environment. The model is required to satisfy both the specified operation sequence of each part and the total part demand volume, which are considered to derive material handling cost in U-shaped flow line cells. In the model several cost-incurring factors including set-up for batch change-over, processing time for operations of each part, and machine failures are also considered in association with processing load and capacity of each cell. Moreover, a heuristic for a good machine layout in each cell is newly proposed based on the material handling cost of each alternative sequence layout. These all are put together to present an efficient heuristic for the U-shaped independent-cell formation problem, numerical problems are solved to illustrate the algorithm.

• 한국항만경제학회지
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• 제22권2호
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• pp.61-82
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• 2006

In order to cope with improvement of labor cost and cargo volume, Korean ports, especially Busan port, are in need of many new facilities. Of course, current facilities should be fully used, and at the same time it needs to make every effort to maximize its productivity as well as cost saving. To this end, this study has decided to focus on automatic yard operation suitable to the domestic container terminal environments, making a survey of many advanced container terminals, trying to find out their common factors, and finally suggesting several alternatives based on the combination of these factors. Also, this study has suggested the present value of initial investment and operating cost by alternative, and at the same time presented the relationship between cargo handling volume and cost/revenue of the optimal alternative, so that it may be of help in decision making.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.550-552
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• 1995

Real time informations from industrial power system in operation can be used for efficient energy conservation, optimal operation of electrical equipments, and expansion planning of apparatus. Requirements for energy conservation and supplied power quality in customers are increasing significantly because of their effects on the production cost and efficiency. Thus, the development of low cost power management system which can can operate in domestic power system properly is substantially requested. In this research, operation software for real time monitoring and control system in customer power system has been developed to achieve the above purposes. The development of the operating software and related technologies are expected to be applied successfully for reducing electricity cost, enhancing power quality, determining facility expansion planning, operating optimal power system, increasing production efficiency, and reducing maintenance cost.

• 국제초고층학회논문집
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• 제6권4호
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• pp.323-326
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• 2017

Sustainability is becoming more and more important in our everyday lives. Thus, it is apparent that more sustainable initiatives are incorporated in a building design concept to reduce operation costs and environmental impacts. However, will the construction cost go up if the building is going green - especially if it is a tall building? This is the question on everyone's mind. In the following paragraphs, we will look into a case study of a skyscraper in Nanning, China. That 411-metre skyscraper, Nanning China Resources Centre East Office Tower, is currently under construction. Designed to LEED-CS Gold standards, the building has adopted a number of sustainable design elements and operation practice, which indeed only accounts for a small percentage of the total construction cost.