• 해양환경안전학회지
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• 제27권7호
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• pp.1067-1073
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• 2021

선박으로부터 발생하는 온실가스 배출을 저감하기 위한 규제가 점차 강화되고 있다. 현존선에서도 EEXI(Energy Efficiency Existing Index)가 도입되었으며 이와 같은 온실가스 배출 감축목표를 달성하기 위해 다양한 연구가 진행되고 있다. 본 연구에서는 국제항해에 종사하는 현존선 중 자동차운반선에 태양광 발전시스템을 적용하여 연료유 사용량을 줄임으로써 온실가스 배출이 저감될 수 있는 시스템을 제안하였다. 제안된 태양광 발전시스템은 태양광 모듈, 에너지저장시스템, 전력변환장치 등으로 구성되었으며, 본 시스템의 적용 가능성을 확인하기 위해 전력전자프로그램을 통해 시스템을 모델링하였으며, 시뮬레이션을 실시하였다. 또한, 실제 선박에 적용하기 위한 타당성 검증을 위해 경제성 분석을 실시하였으며, 약 11년 이후 경제성 부분에서도 유의미한 결과가 도출됨을 확인할 수 있었다.

• 한국물환경학회지
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• 제22권1호
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• pp.97-103
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• 2006

Excess sludge treatment and disposal currently represent a rising challenge for domestic or wastewater treatment plants due to economic, environmental and regulation factors. Conventional gravity sedimentation process has been widely used in sludge thickening. The operation method of the process is very simple, but the process requires long detention time for sludge thickening, uses polymers, and shows low sludge thickening efficiency. To solve the problems, we studied on DAF (Dissolved Air Flotation) system. We use bulking sludge of a paper manufacturing plant. The effects of parameters such as SVI (Sludge Volume Index), storage time, initial concentration and wet density of excess sludge were examined. The results showed that the more SVI was low, the more sludge was thickened. As storage time goes by, SVI was increased and thickening performance was deteriorated. In order to improve flotation performance at high concentration, high recycling ratio and pressure did not increase the concentration due to thickening limitation. The addition of 0.8 g/L of loess was increased flotation efficiency of 1.41 times.

• 한국지열·수열에너지학회논문집
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• 제10권1호
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• pp.7-13
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• 2014

This study intends to analyse the economical aspect of a GSHP(Ground Source Heat Pump) system compared to the conventional system which is consisted with a boiler and a chiller. This study has simulated four systems in Incheon. It developed and analyzed for applications in a residential and an office building which was based on the hourly EPI(Energy Performance Index, $kWh/m^2yr$). Case 1 is utilizing a boiler and a chiller to meet heating and cooling demand of a house. Case 2 is utilizing the same conventional set up as Case 1 of a office. Case 3 is summation of Case 1(house) and 2(office) systems and loads. And Case 4 is utilizing a GSHP to meet the combined loads of the house and office. The method of the economic assessment has been based on IEA ECBCS Annex 54 Subtask-C SPB(Simple Payback) method. The SPB calculated the economic balanced year of the alternative system over the reference system. The SPB of the alternative systems (GSHP) with 10%, 30% and 50% initial incentive has been calculated as 9.38, 6.72 and 4.06 year respectively while the SPB without initial incentive of systems was 10.71 year.

• 한국인터넷방송통신학회논문지
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• 제23권1호
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• pp.151-156
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• 2023

본 논문은 주어진 예산과 광고를 접하는 최소 인원수를 초과하는 제약조건을 만족시키면서 신제품에 대한 인지도를 극대화시키기 위해 다수의 광고매체들 중에서 어느 광고매체를 몇 회 광고해야 하는지를 결정하는 최적화 문제를 다룬다. 본 문제에 대해 지금까지는 선형계획법 (LP) 소프트웨어 패키지를 활용하는 수학적 접근법만이 활용되고 있으며, 다항시간 알고리즘은 제안되지 않고 있는 실정이다. 본 논문은 이 문제에 대해 O(nlog n) 수행 복잡도의 다항시간으로 최적 해를 얻을 수 있는 휴리스틱 알고리즘을 제안한다. 제안된 방법은 광고매체를 가장 경제적으로 선정하는 평가기준을 제안하였으며, 이 평가기준을 적용하여 광고매체 선정과 광고횟수를 결정하였다. 제안된 알고리즘은 Excel을 활용하였음에도 불구하고, 실험 데이터에 적용한 결과 LP와 동일한 결과를 얻었다.

• 기술사
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• 제45권5호
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• pp.26-35
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• 2012

Korea is now the 12th largest economy in the world, surpassing its annual trade in the amount of $1 trillion, and it has joined the socalled 20-50 Club, becoming one of the seven countries in the world with capita income of more than $20,000 with population of 50 million. However it ranked 24th of the Global competitiveness index evaluated by World Economic Forum based on the basic requirements including infrastructures, efficiency enhances, innovation and sophistication factors, etc. The extensive and efficient SOC infrastructures are critical for ensuring the global competitiveness of each country. Effective modes of SOC facilities including quality roads, railroads, ports, air transport, etc will be able to reduce the annual traffic congestion cost as well as macro economic logistics costs in Korea, thereby the global competitiveness can be strengthened in the global market.

• East Asian Economic Review
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• 제24권4호
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• pp.389-416
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• 2020

This paper provides empirical evidence on the reorganization of GVCs in East Asia, highlighting that structural trends explain a decrease in the fragmentation of production after 2011 but that it is not the result of rising trade costs along the value chain. Using harmonized inter-country input-output tables, the paper first analyzes the global import intensity of production to document changes in the structure of GVCs. It then calculates theory-consistent bilateral trade costs for intermediate and final products using an approach derived from the gravity literature and introduces a new index of cumulative trade costs along the value chain. These data are used to discuss whether the decrease in global imports is the consequence of shifts in demand, efficiency-enhancing strategies of firms or rising trade costs. Between 2011 and 2016, cumulative trade costs have decreased in East Asian GVCs. However, as COVID-19 is likely to intensify trade and investment uncertainties, trade costs could increase in the future. Policies aimed at reducing uncertainties and preserving the gains from trade and investment liberalization will be key in this new environment.

• International Journal of Quality Innovation
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• 제8권1호
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• pp.40-75
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• 2007

In the early industrial age which with high intensity of machine and labor, using financial measurement index was good enough to tie in company's mechanization and philosophy of management and been in efficiency. But being comply with "New Economic age," a new economic environment is full of knowledge and information, the enterprise competition had changed from tangible assets, plants to intangible innovation ability of knowledge. As recognizing the new tendency by enterprise, they value gradually the growth and influence from learning. Practice of organization learning not only needs firm structure and be in coordination with both hardware and software, but also needs an affect measurement model to offer enterprise to estimate learning performance. It's a good instrument of financial performance measure mold in the past years, But it's for measuring the past, couldn't formulate enterprise trend to future, hard to estimate investment for future, such as development of products, organization learning, knowledge management etc, as which intangible assets and knowledge ability just the key factors of being win around competition environment in the future. In 1992, Kaplan and Norton brought up Balance Scorecard (BSC) on Harvard Business Review, as an instrument helping enterprise to measure performance, which is being considered to be a most influence management instrument. It added non-financial index such as customer, internal process and learning growth besides traditional financial index, as offering enterprise an index to measure and manage intangible assets and intellectual property. As being aware of organization learning is hard to be ignored in the new economic age, this research is based on learning and growth of BSC, and citing one national material company try to let the most difficult measurement performance of organization learning, to be estimate through BSC, analyze of factor and individual case, to discuss the company how to make the related strategy and vision of organization learning to develop learning and growth of the structure of BSC, subject the matter of out put factors to be discussed, and measure the outcomes as a result of research. The research affect offers (1) the base implement procedure of carrying out BSC; (2) the reference of formulating measurement index while enterprise using BSC to estimate performance of organization learning; (3) the possibility bottleneck maybe forcing while carrying out BSC, to be an improvement or preventive for enterprise.

• 한국항만경제학회지
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• 제32권2호
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• pp.91-103
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• 2016

본 연구는 DEA-CCR, BCC 그리고 Malmquist 지수를 이용하여 국내 화물자동차운송업체의 효율성과 생산성을 분석하는 것을 연구의 목적으로 하였다. 취급량 기준 국내 상위 14개 화물자동차운송업체를 분석대상으로 하였으며, 투입변수로 화물취급업소 수, 트럭 수, 자산을 이용하였으며, 산출변수로 취급량과 매출액을 선정하였다. 화물자동차운송업체의 효율성 분석을 위해 DEA 모형을 적용했으며, Malmquist 지수를 적용하여 생산성을 분석하였다. DEA분석 결과 DMU4,5,10 총 3개 업체의 CCR, BCC, 규모의 효율성이 모두 1로 효율적 운영이 이루어지고 있는 것으로 나타났다. 한편 Malmquist 지수분석결과, 2012-2013년도를 제외하고는 모두 1보다 작은 값을 보여 생산성이 감소한 것으로 나타났고, TECI는 2012-2013년도를 제외하고 지수가 모두 1보다 높아 효율성이 높은 것으로 나타났지만, TCI는 반대로 2012-2013년도를 제외하고 모두 1보다 낮은 지수로 기술이 퇴보된 추세로 분석됐다.

• 한국항만경제학회지
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• 제38권2호
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• pp.123-138
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• 2022

우리나라는 동북아지역에서 아시아 허브항만의 위상을 유지하기 위해 항만시스템의 업그레이드에 막대한 예산을 투입하고 있다. 그 결과로 우리나라 대표항만인 부산항은 세계 5위 수준의 컨테이너 물동량 처리 수준을 보이고 있다. 그러나 부산항을 제외한 다른 항만은 낮은 순위에 자리하고 있다. 이 연구는 자료포락분석(DEA) 모델과 Malmquist 생산성지수(MPI)를 이용하여 국내 주요 항만의 효율성과 생산성을 분석하는데 목적이 있다. 특히 변수의 수가 의사결정단위(DMU) 수를 초과할 경우 판별력이 약해지는 DEA모델을 보완하기 주성분분석(PCA, Principal Component Analysis)을 DEA모델에 결합한 PCA-DEA모델을 이용하였다. 그리고 MPI는 다년간의 항만의 생산성을 측정하기 위하여 적용하였다. 그 결과로 우리나라 주요항만의 효율성과 생산성 순위를 결정할 수 있었으며, 광양항과 울산항 2010년과 2018년 비교시 효율성 측면에서 상위권을 보였으며, 생산성 분석 결과에 있어서 대산항과 목포항이 다른 항만에 비해 상대적으로 높게 나타났다. 이 연구결과는 항만별 경쟁력을 객관적으로 평가하고 전략을 마련하는데 활용될 수 있다.

• 산업경영시스템학회지
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• 제45권3호
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• pp.49-56
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• 2022

ROK Navy intends to secure the Korean-type aircraft carrier in order to effectively prepare for various future security threats. In general, the Korean national competency is considered to be at the level of having an aircraft carrier, but it is unclear what scale aircraft carrier would be appropriate. In this study, the efficiency was evaluated through the relative comparison between national competency(national power, economic power) and the scale of aircraft carriers, and the optimal scale of the Korean-type aircraft carrier that could be acquired was presented. A DEA(Data Envelopment Analysis) model was applied to aircraft carriers(19 aircraft carriers in 11 countries) currently in operation and scheduled to be possessed in the world. As input variables, CINC(Composite Index of National Capability) and GDP(Gross Domestic Product), which are the most widely used as indicators of national and economic power, and as output variables, the full-load displacement, length, and width of aircraft carriers were selected. ARIMA(short-term within 5 years) and simple regression(long-term over 5 years) were used to estimate the future national competency of each country at the time of aircraft carriers acquisition. The relative efficiency score of the Korean-type aircraft carrier currently being evaluated is 1.062, and it was evaluated as small-scale aircraft carrier compared to the national competency. Based on Korean national competency, the optimal scale of the Korean-type aircraft carrier calculated by aggregating benchmark groups, is 58,308.1 tons of full-load displacement, 279.4m in length, and 68.3m in width.