• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.221-224
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• 2002

포항제철소에는 13개의 발전기가 있어 제철소에서 필요로 하는 전력을 자체적으로 945MWH 규모로 공급하고 있다. 발전소에서 사용되는 에너지원은 제철공정에서 부수적으로 발생하는 부생가스(BFG, COG, LDG, CFG)와 외부에서 구매하는 중유, LNG가 있다. 안정적인 전력공급과 비용절감을 위한 발전기 가동계획을 수립하기 위해서는, 조업상황에 따라 변동되는 전력소요량 및 부생가스 발생량을 예측하여 발전기별로 사용될 연료량을 배분하고, 발전기별 효율을 반영한 발전량을 결정하게 된다 이러만 발전기 가동계획 수립을 수작업에 의존하고 있어, 수시로 변화하는 상황에 신속한 대처가 곤란하고, 모든 요소를 고려하기가 어려워 에너지비용을 절감할 수 있는 기회손실의 우려가 있었다. 본 연구에서는 LP 및 NLP를 적응하여 발전기별 연료배분 및 발전량을 결정하는 과정을 자동적으로 수행하는 발전기 가동계획수립 Model을 개발하였다. Data 입·출력용으로 Excel, LP Package는 What's Best, Programming Language는 VBA(Visual Basic for Application)를 활용하였다.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.179-184
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• 2012

Environmental impact is getting more attention in many feasibility studies for railroad-related projects and research items. For sustainable growth and green transportation, the benefits typically used for feasibility studies in railway-related projects, are composed mostly of economic criterions which is not considering growing attention on changing paradigm. Based on the analysis of current methodologies, improvements in estimating environmental impact especially on noise and pollution are suggested. Active steering bogie has been proposed to satisfy stabilizing and steering performance of railroad. This paper describes the feasibility study of the active steering bogie for a urban railway vehicle based on environment-related criteria.

• Journal of Energy Engineering
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• v.17 no.3
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• pp.139-144
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• 2008

Recently due to march as the high oil price, It is necessary for Korea to grope a plan, which is to increase the energy efficiency of existing facilities as well as to develop overseas gas and oil resources. With this point, this work carried out to approach the high pressure LNG pipeline network of Inchon receiving terminal with Newton method as corrective flowrate. We found that the high pressure network mainly depends on FCVs(Flow Control Valves). The high pressure pump showed the maximum efficiency at the FCVs of 50% opening and could discharge LNG only above the LNG head of 1,500m from a system curve obtained. The operating cost of pumps was estimated from their operating points. We compared the operating cost under normal operation with the operating cost under maximum efficiency. Especially, we obtained the day savings of a year as wells as the hour savings of a day. From the results, the high pressure network win be able to reduce the operating cost of 138 million wons in a year. This means that a pump can reduce the operating cost of 9,823 thousands won. Consequently, this work could find the operating features of the pumps under the complicated high pressure LNG network and the savings effect of the pump operating cost. Also, the results will be able to macroscopically contribute the heightening of national energy competitiveness as well as to microscopically contribute the future effective operation of LNG receiving terminal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.149-158
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• 2019

The scheduling of planned maintenance problem of a system consisting of a number of components was studied. The purpose of maintenance scheduling is to minimize the cost of maintaining long-term operations. On the system side, the cost of a system shutdown can be minimized by grouping and inspecting a number of components. In addition, proper inspection cycles can be selected for each component to identify the failure sufficiently early to minimize the cost of the failure. To reduce the complexity of the calculations, the 'base interval approach' used in previous studies was applied and, in addition, the inspection cost savings from simultaneous inspections of multiple components were considered. To compare the effectiveness of inspection cost savings, this paper presents the results of simulation analysis performed by referring to the cases in the existing studies.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1057-1063
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• 2014

Concerning $CO_2$ reduction from International Societies, lots of laboratories and relevant societies suggest many reports on how to reduce fuel consumption from their specific ways. Undoubtedly, cutting costs is the final desired destination for owner outcome, but many questions there are on the way yet: how is this measure working? how efficient is it? On what size of ship would it work best and be the most effective? etc. Fuel cost is one of the major cost elements for ship owners and/or operators. And by reducing fuel consumption owners and/or operators will reduce both their costs and the environmental impact from their ship. This paper is aim to address how the measures work for saving fuel consumption through improve propulsion efficiency, installation cost and benefit can be calculated easily in the return on investment for estimated one year operation, and finally their compatibility with other fuel saving measure devices.

• Journal of Environmental Policy
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• v.9 no.4
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• pp.3-27
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• 2010

In this paper, we have analyzed the cost structure of the Korean manufacturing industry in relation to the central government's environmental investment(CGEI below) by applying translog variable cost function. Important findings are as follows. First, sufficiency degree of CGEI of 0.7230, less than optimal level of 1, causes production inefficiency. Therefore, central government should forward a strategy to raise CGEI to meet appropriate standards. In addition, inspite of the deficiency of CGEI, shadow priceis lower than market price due to q-value of 0.9572, yielding unfavorable conditions for CGEI. However, CGEI brings about increase in output, variable cost saving, and economies of scale of firms. Second, by comparing this study with an existing study(2010), we have discovered the following facts. In both studies, we find that there are deficiency of investment, unfavorable conditions in investment, economies of scale, and output increase due to investment. However, the current study has found that, CGEI, which shows efficiency by positive(+) shadow price, saves variable cost. Therefore, firms suffer from production inefficiency due to variable cost caused by a shortage of efficient CGEI. Moreover, the previous study conducted in 2010 found that investment in prevention of environmental pollution(IPEP below), which indicates inefficiency by negative(-) shadow price, cannot reduce variable cost. In such circumstances, firms yield abnormal production efficiency based on variable cost savings caused by inefficient IPEP. For this reason, firms should raise IPEP to optimal level to reduce IPEP inefficiency to achieve production efficiency by reducing variable cost.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.273-285
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• 2012

Current TMDL based on the 'Polluter Pays Principle' in Republic of Korea is individually operated by each local government for the designed allocated pollution load of unit watershed and unit district. However, unlike the motion of the air contaminants, the polluted contaminants in a river move from upstream to downstream, and a river can affect to districts more than two. In addition, a decision making on the construction of a sewage treatment facilities follows the concept of 'economy of scale'. These reasons support the collaboration among local governments in order to reduce the costs in improving water quality. This study suggested a method to reduce water quality management cost by redistributing reduction load considering cost-effectiveness for an entire watershed. The assessment on the suggested method is conducted in Youngsan river watershed. Without variation in total load, reduction load assigned for unit watershed and unit district is retributed in the region where pollutant source is concentrated, and then water quality and cost reduction improved from the redistribution of reduction load is analyzed. The results show that the cost saved by the suggested method is KRW 124 billion for scenario-1 and 172 billion for scenario-2 considering total cost of KRW 788 billion for the existing plan. We expect that the suggested method is a good example to reduce water quality management cost in local governments for TMDL.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.595-598
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• 2004

외식업체에서 비용의 가장 많은 부분을 차지하는 것이 인건비이다. 따라서 종업원 스케쥴링은 비용절감을 위한 중요한 요소이다. 그러나 스케쥴링은 여러 가지 요구 조건들을 만족시켜야 하므로 복잡하고 많은 시간과 노력이 소요되는 비생산적인 업무이다. 본 연구의 목적은 수리계획법을 이용하여 스케쥴링 업무에 드는 시간과 비용을 절감하고 인력을 효율적으로 관리하는 방안을 모색하는 것이다. 이러한 연구목적을 위해 본 연구에서는 사례기업을 대상으로 수리계획법의 현실 적용효과와 문제점을 확인하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.120-125
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• 2007

경관조명은 야간관광자원 활성화를 통한 대외 경쟁력을 강화하고, 도시경쟁력을 향상시키며, 관광객들에게 도시 브랜드를 전달할 수 있는 수단으로 중요시되고 있다. 본 연구는 경관조명의 활성화에 따른 유지관리 비용을 절감할 수 있는 방안을 검토하기 위하여 국제 조명위원회(CIE)에서 제시하고 있는 조도 및 휘도 기준을 조사하였으며, 한강상 교량과 일산호수공원의 일부 지역에 대한 경관조명 설치현황 및 전력요금 사용실태를 조사하였다. 또한 '조명연출방법'과 '조명자재 선정에 의한 방법'에 따라 유지관리 비용 절감 현황을 검토하였으며, 각 회로를 세분화 하여 시간대별 제어가 가능하도록 하고, 조명연출에 적합한 조명 자재를 선정하여 적용함으로써 유지관리 비용이 절감됨을 알 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1335-1338
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• 2005

최근에 정부는 IT839 전략을 발표하여 IT 산업의 새로운 서비스 도입과 신규 수요 창출에 역량을 집중하고 있으며, 신규 서비스로서 RFID/USN 도입을 강력히 추진하고 있다. 또한 민간분야에서도 유비쿼터스 환경에서 센서 네트워크를 이용한 여러 가지 연구가 활발히 진행되고 있는데, 이러한 센서 네트워크가 경제적으로 성공하기 위해서는 유지보수 비용절감이 필수적이다. 본 논문에서는 센서 네트워크의 유지보수 비용을 최소화하기 위한 방법으로 온디맨드 패러다임에 의한 에너지 절감 방안을 제시한다. 구체적으로 센서 네트워크의 각 구성요소에 온디맨드 패러다임을 어떻게 적용하여 에너지 절감의 최적화를 이룰수 있는지와 센서 네트워크와 상위 정보네트워크간의 관계를 설명한다.