• 한국경제지리학회지
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• 제12권4호
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• pp.540-556
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• 2009

허브-스포크 망은 항공, 육상 교통 및 정보통신분야에서 유동의 규모의 경제를 고려하여 기간망을 설계하는 대표적인 입지 최적화 문제이다. 이 연구는 우선, 기존의 허브 스포크 망에 관한 지리학 및 타 분야의 연구 경향과 함께 최근 논의되고 있는 신뢰성에 기반한 허브 입지 모델을 소개한다. 기본 모델은 입지 배분 방식에 따라 단일 배분 및 다중 배분 입지 모델로 구분되고, 기본 모델의 확장 형태로서 최소 유동량 제약을 적용한 입지 디자인 모델이 제시되었다. 모델의 행태를 살펴보기 위해 미국의 15개 도시의 신뢰성 및 유동 자료를 이용하여 네트워크의 규모의 경제성과 네트워크 비용, 그리고 신뢰성간의 관계에 초점을 두어 분석을 하였다. 이 연구는 경제성과 신뢰성에 바탕을 둔 입지 문제 및 네트워크 최적화 분야에 고려해야 할 요인의 특성을 밝혔다는 점에서 그 중요성이 강조된다.

• Water Engineering Research
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• 제5권2호
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• pp.81-99
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• 2004

Long term streamflow regime under virtual climate change scenario was examined. Rainfall forecast simulation of the Canadian Global Coupled Model (CGCM2) of the Canadian Climate Center for modeling and analysis for the IPCC SRES B2 scenario was used for analysis. The B2 scenario envisions slower population growth (10.4 billion by 2010) with a more rapidly evolving economy and more emphasis on environmental protection. The relatively large scale of GCM hinders the accurate computation of the important streamflow characteristics such as the peak flow rate and lag time, etc. The GCM rainfall with more than 100km scale was downscaled to 2km-scale using the space-time stochastic random cascade model. The HEC-HMS was used for distributed hydrologic model which can take the grid rainfall as input data. The result illustrates that the annual variation of the total runoff and the peak flow can be much greater than rainfall variation, which means actual impact of rainfall variation for the available water resources can be much greater than the extent of the rainfall variation.

• 멤브레인
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• 제21권2호
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• pp.107-117
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• 2011

바나듐 레독스-흐름 전지 (V-RFB)는 대용량 전력저장 시스템의 하나로 연구가 많이 진행되고 있다. 특히 최근에 지구온난화의 해결을 위한 태양광, 풍력 발전 등 재생에너지에 의한 발전과 함께 이 전력 원들의 부하 평준화 및 전력 공급 원활화 등을 위한 전력 저장 시스템의 하나로 주목을 받고 있다. 본 총설에서는 V-RFB 에 대한 원리 및 구성, 최근 연구 동향, 경제성, 요소기술에 대해 설명하고자 한다.

• 한국경제지리학회지
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• 제1권1호
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• pp.113-135
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• 1998

관광개발이 지역경제에 미치는 파급효과를 분석하기 위하여 투입-산출분석, 관광소득승수분석, 노동창출효과분석 등의 방법을 사용해 왔으나, 2차적 자료가 부족한 소지역을 대상으로 하는 분석에는 적응하기 어려운 실정이다. 본 연구에서는 관광사업체를 대상으로 하는 현지 조사에 근거하여 관광객으로부터 관광사업체로 유입되고 사업체에 의해 지출되는 화폐흐름을 추적하는 '관광지출흐름분석' 방법의 타당성을 검증하고자 한다. 3개의 사례지역을 대상으로 한 조사로부터, 이 방법이 관광개발이 유발하는 연간 지출액의 규모와 그 지리적 범위를 추정하게 하고 생산액, 노동유발효과 등 지역경제에 대한 의미있는 지수를 측정할 수 있게 함을 알 수 있다.

• 상하수도학회지
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• 제38권1호
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

• 한국경제지리학회지
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• 제12권4호
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• pp.406-420
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• 2009

유럽연합의 경제적 통합과 지리적 확대는 역내 회원국간 교역흐름과 교역구조에 많은 변화를 가져왔다. 첫째, 유럽연합의 역내 교역량은 경제통합과 단일시장 확대로 지속적으로 증가해 왔다. 이러한 교역량 확대는 시장통합에 따른 회원국간 무역창출 및 무역전환효과에 의한 것이기도 하지만, 신규 회원국의 가입에 따른 시장확대에 의해 이루어졌으며 신규 회원국의 가입이 교역량 증대에 미치는 효과는 점차 약화되고 있다. 둘째, 경제통합과 단일시장 확대에 따른 무역확대로 서부유럽은 물론 남부유럽과 중 동부유럽의 역내시장에 대한 수출 입 의존도는 증대되었다. 특히 남부유럽 및 중 동부 유럽의 역내 수출 입 의존도가 상대적으로 더 높게 증가하였다. 셋째, 유럽연합의 역내 회원국간 교역구조는 상품의 자유로운 이동과 단일시장 확대로 규모경제가 가능해짐으로써 상품의 차별화에 의한 산업내 교역이 증가하였다. 산업내 교역에서도 수평적 산업내 교역은 감소하고 수직적 산업내 교역은 증가하였다. 그리고 산업내 교역은 서부유럽의 교역에서 높았으며 산업간 교역은 남부유럽 및 중 동부유럽의 교역에서 상대적으로 높게 나타났다. 그러나 남부유럽 및 일부 중 동부유럽국가의 교역구조도 산업간 교역에서 산업내 교역으로 변화되고 있다.

• 한국항만경제학회지
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• 제18권2호
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• pp.109-133
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• 2002

The China entered World Trade Oganization(WTO) last year, thus opening its border to more - and freer - trade. With its foreign trade rapidly expanding and with economic growth continuing at a substantial -rate, China will be the largest container traffic generating country in the world. In the light of this potential trade bonanza, regional ports in North-East Asia strive to gain a competitive-edge. The Port of Busan, the world's third largest container port, wants to capture a significant share of the china's container cargoes. In this circumstance, development strategies of the Port of Busan are suggested as follows. First, to cope with increasing volumes, the New Busan Port on Gaduk island should be constructed without failure. Second, it is necessary to add modernized high-performance gantry cranes and to train crane operators' skill. Third, it needs to apply Dwell Time- Sliding Scale System for transshipment cargoes. Fourth, it needs to develop the EDI network in terminal areas or adjacent hub ports to exchange trustworthy and satisfactory informations Fifth, port authority -needs to enlarge designated Free Trade Zone to facilitate the free flow of cargoes. Sixth, the restoration of rail links between North and South Korea is abundantly clear. Thus it needs to enlarge railroad facilities in advance. Seventh, it needs to establish the Port Authority of Busan immediately. Finally, it needs to strengthen port sales and to open events like 'Marine Week 2001' regularly to attract potential canters or big shippers.

• 청정기술
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• 제2권2호
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• pp.51-59
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• 1996

Billions of tons of industrial waste are generated annually in industrialized countries. Managing and legally disposing of these wastes costs tens to hundreds of billions of dollars each year, and these costs have been increasing rapidly. The escalation is likely to continue as emission standards become even more stringent around the world. In the face of these rapidly rising costs and rapidly increasing performance standards, traditional end-of-pipe approaches to waste management have become less attractive. The most economical waste management alternatives in many cases have become recycling of the waste or the redesign of chemical processes and products so that wastes are prevented or put to productive use. These strategies of recycling or reducing waste at the source have collectively come to be known as pollution prevention. The engineering challenges associated with pollution prevention are substantial. This presentation will categorize the challenges in three levels. At the most macroscopic level, the flow of materials in our industrial economy, from natural resource extraction to consumer product disposal, can be redesigned. Currently, most of our raw materials are virgin natural resources that are used once, then discarded. Studies in what has come to be called industrial ecology examine the material efficiency of large-scale industrial systems and attempt to improve that efficiency. A second level of engineering challenges is found at the scale of individual industrial facilities, where chemical processes and products can be redesigned so that waste is reduced. Finally, on a molecular level, chemical synthesis pathways, combustion reaction pathways, and other material fabrication procedures can be redesigned to reduce emissions of pollution and unwanted by-products. All of these design activities, shown in Figure 1, have the potential to prevent pollution. All involve the tools of engineering, and in particular, chemical engineering.

• 품질경영학회지
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• 제50권1호
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• pp.153-167
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• 2022

Purpose: The purpose of this study is to guide the operation managers who plan daily production of large mass-processing facility that services multi-customers with multi-product, small-batch item characteristics by providing the practical best production quantity and the inventory allowed to build. Methods: Close observation of a subcontract paint-shop operator captured the daily decision process which was reflected in the subcontractor-unique mathematical model and the system dynamics simulation model. Multiple simulations were run to find the practical best production quantity and the maximum allowable stock level of inventory that did not undermine the profit from practical best daily production. Actual data and a few constant values were obtained from the firm under study. Results: While the inventory holding cost for the customer-owned material harms the total profit of the subcontractor, the running cost of the processing facility hinders production in small batches. This balances the maximum possible productions and results in practical best daily production which can be found through simulation runs with actual data. The maximum level of stocked inventory is deduced from the practical best daily production. Conclusion: To build a large volume that enables economy-of-scale production, operators should deal with multi-product small-batch items from multiple customers. When the planned schedule of the time and amount of material in-flow tend not to be reliable, operators can find it practical to execute level production across the planning horizon instead of adjusting to day-to-day in-flow fluctuations.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.142-142
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• 2023

Humans inevitably and continuously produce wastewater in daily life worldwide. To decrease the degradation of river water bodies and aquatic ecosystem therein, humans have built systems at different scales to collect, drain, and treat household-produced wastewater. Particularly, municipal wastewater treatment plants (WWTPs) with centralized controls have played a key role in reducing loads of nutrients in domestic wastewater for the last few decades. Notwithstanding such contributions, impaired rivers regarding water quality and habitat integrity still exist at the whole river basin scale. It is highly attributable to the absence of dilution capacity of receiving streams and/or the accumulation of the pollutant loads along flow paths. To improve the perspective for individual WWTPs assessment, the first crucial step is to achieve systematic understanding on spatial distribution characteristics of all WWTPs together in a given river basin. By taking the initiative, our former study showed spatial hierarchical distributions of WWTPs in three large urbanized river basins in Germany. In this study, we uncover how municipal WWTPs in the contiguous United States are distributed along river networks in a give river basin. The extended spatial scope allows to deal with wide ranges in geomorphological attributes, hydro-climatic conditions, and socio-economic status. Furthermore, we identify the relation of the findings with multiple factors related to human activities, such as the spatial distribution of human settlements, the degree of economy development, and the fraction of communities served by WWTPs. Generalizable patterns found in this study are expected to contribute to establishing viable management plans for recent water-environmental challenges caused by WWTP-discharges to river water bodies.