• 한국농공학회논문집
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• 제65권5호
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• pp.37-49
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• 2023

The drought risk has been increasing recently due to climate change causing the extreme climate to be more frequent. In order to supply agricultural water stably under drought, it is necessary to operate an agricultural reservoir in response to drought. To this end, it is crucial to establish appropriate drought response operation rules considering weather conditions and reservoir status. In the reservoir operation simulation, the supply amount differs from the actual reservoir supply for many reasons, including maintaining water levels for supply and accommodating farmers' requests. So, for a more realistic reservoir operation simulation, it is necessary to reflect the reservoir operation rules of the actual water management site. Therefore, in this study, through a survey, the standards for limitation of agricultural water supply applied to agricultural reservoirs in Korea were investigated, and the criteria for drought response reservoir operation (DRO) were established based on the survey. Then, the DRO was applied to the irrigation period for nine subject reservoirs. The applicability was evaluated by comparing the DRO result to the operation result of HOMWRS (Hydrological Operation Model for Water Resources System). The reservoir drought index, storage rate, and daily supply were compared for evaluation. From the result, DRO showed more stable operation results in most cases against drought as it has fewer days of water supply limitation and a somewhat reservoir storage rate which can be utilized for prolonged drought.

• 환경영향평가
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• 제9권3호
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• pp.203-214
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• 2000

Health risk assessment is applied to streamlining LCA(Life Cycle Assessment) using Monte carlo simulation for probabilistic/stochastic exposure and risk distribution analysis caused by data variability and uncertainty. A case study was carried out to find benefits of this application. BTC(Benzene, Trichloroethylene, Carbon tetrachloride mixture alias) personal exposure cases were assumed as production worker(in workplace), manager(in office) and business man(outdoor). These cases were different from occupational retention time and exposure concentration for BTC consumption pattern. The result of cancer risk in these 3 scenario cases were estimated as $1.72E-4{\pm}1.2E+0$(production worker; case A), $9.62E-5{\pm}1.44E-5$(manger; case B), $6.90E-5{\pm}1.16E+0$(business man; case C), respectively. Portions of over acceptable risk 1.00E-4(assumed standard) were 99.85%, 38.89% and 0.61%, respectively. Estimated BTC risk was log-normal pattern, but some of distributions did not have any formal patterns. Except first impact factor(BTC emission quantity), sensitivity analysis showed that main effective factor was retention time in their occupational exposure sites. This case study is a good example to cover that LCA with probabilistic risk analysis tool can supply various significant information such as statistical distribution including personal/environmental exposure level, daily time activity pattern and individual susceptibility. Further research is needed for investigating real data of these input variables and personal exposure concentration and application of this study methodology.

• 한국화재소방학회논문지
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• 제22권5호
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• pp.29-34
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• 2008

본 연구에서는 대피자의 최적 배연조건 확립을 위하여 CFD모델을 이용한 수치해석을 통해 지하철 승강장 내에서의 화재 시 다양한 배연조건에서의 화재 위험성을 검토하였다. 결과로 스크린도어를 설치한 경우가 설치하지 않은 경우보다 온도의 상승폭이 최대 $65.37%{\sim}74.97%$ 낮게 나타났다. 또한 급기나 압인배기시 승강장에 난류가 발생함에 따라 온도 및 연기층이 교란되어 하락됨에 따라 탈출시 위험을 유발할 수 있는 것으로 판단되었다. 따라서 배연용량 및 승강장 공간 설정시 배연조건에 따른 화재 특성을 고려한 설계가 필요하다.

• Industrial Engineering and Management Systems
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• 제11권1호
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• pp.1-10
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• 2012

Supplier selection is an essential task within the purchasing function of supply chain management because it provides companies with opportunities to reduce various costs and realize stable and reliable production. However, many companies find it difficult to determine which suppliers should be targeted as each of them has varying strengths and weaknesses in performance which require careful screening by the purchaser. Moreover, information required to assess suppliers is not known precisely and typically fuzzy in nature. In this paper, therefore, fuzzy multi-objective linear programming (fuzzy MOLP) is presented under fuzzy goals: cost minimization, service level maximization and purchasing risk. To solve the problem, we introduce an enhanced two-phase approach of fuzzy linear programming for the supplier selection. In formulated problem, Analytical Hierarchy Process (AHP) is used to determine the weights of criteria, and Taguchi Loss Function is employed to quantify purchasing risk. Finally, we provide a set of alternative solution which enables decision maker (DM) to select the best compromise solution based on his/her preference. Numerical experiment is provided to demonstrate our approach.

• Environmental Engineering Research
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• 제24권1호
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• pp.63-73
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• 2019

This study suggests a method for calculating the benefits of water pipe renewal based on an estimate of the water supply suspension risk. The proposed method based on five benefit items is more direct and specific than other benefit estimation methods. In addition, a methodology evaluating the economics of pipe renewal based on pipe failure rate is proposed for estimating the optimal renewal point from an economic perspective. By estimating the optimal renewal period based on a yearly benefit cost ratio per pipe in a case study area, it was possible to draft an optimal renewal plan for the subject region from an economic perspective. Compared with other methodologies, a reasonable optimal renewal period was derived from an economic point of view. The result of this study may be used to develop future water pipe renewal plans. Moreover, the proposed methodologies and results derived from this study can be applied to asset management plans.

• The Journal of Asian Finance, Economics and Business
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• 제9권10호
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• pp.49-59
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• 2022

This paper examined the impact of real exchange rate volatility on trade balance in Malaysia by using quarterly data from year 2000 until 2019. Generalized Autoregressive Heteroscedasticity (GARCH) model was used to extract the volatility component of real exchange rate before examining its impact on trade balance. Furthermore, Autoregressive Distributed Lag (ARDL) model was used to investigate the long-run relationship and short-run dynamic between trade balance, money supply, national income and volatility of exchange rate. Empirical results show the existence of co-movement between variables under study in the long-run. However, the results also suggest that volatility of real exchange rate does not significantly affect trade balance neither in the long-run nor short-run. The risk which is associated in the movement of exchange rate do not influence trader's behaviour toward Malaysia exports and imports. Thus, it should be note that any depreciation or appreciation in Malaysian Ringgit do not have an impact towards trade balance either it is being further improved or deteriorates. Hence, exchange rate volatility may not be too concern for policymakers. This may be partially due to manage floating exchange rate regime that has been adopted by Malaysia eventually eliminated the element of risk in the currency market.

• 한국산학기술학회논문지
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• 제17권10호
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• pp.635-646
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• 2016

본 논문에서는 한국의 주택분양시장과 전세시장 간의 특징적인 상관관계를 고려하여 선분양제도 하에서 분양물량과 전세물량을 동시에 공급하여 안정적으로 주택사업을 수행할 수 있는 주택사업모델을 제안하고자 한다. 본 논문에서 제안한 주택사업모델 상에서 분양물량 및 전세물량의 비율 변화에 따른 위험분산효과를 검토하기 위하여 마코위츠 포트폴리오 이론을 활용하였다. 분양물량과 전세물량을 결정하기 위하여 분양물량을 결정하는 대리변수로 주택매매가격지수를, 전세물량을 결정하는 대리변수로 주택전세가격지수를 활용하였다. 또한 주요 지역을 대상으로 제안한 주택사업모델의 지역별 위험분산효과를 확인하였다. 분석 결과를 종합하면, 먼저 본 연구에서 제안한 주택사업모델은 시장 변동에 따라 특징적인 동태적 관계를 가지고 있는 매매시장과 전세시장의 특성을 반영한 방안임에 따라 위험분산효과는 존재하는 것을 확인되었다. 이는 결국 본 논문에서 제안하는 주택사업모델이 기본적인 가능성을 확인시켜줄 수 있을 것으로 판단된다. 또한 지역별 주택시장 특성에 따른 가격변동 리스크에 효과적으로 대응할 수 있는 것으로 나타났다. 본 논문에서 제안한 주택사업모델을 통해 시행사, 건설회사, 소비자 및 정부 등 각종 시장 참여주체들은 각각 다양한 효과를 기대할 수 있다. 하지만 실제적으로 본 모델을 시장에 적용하기 위해서는 정부의 재정적 지원이 필요할 것으로 판단된다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.101-105
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• 2002

In a traditional hierarchical inventory system, direct orders are the only information for inventory management that is exchanged between the firms involved. But due to the rapid development of modern information technology, it becomes possible for the firms to share more information in real time, e.g. demand and inventory status data. And so the term Supply Chain has emerged because it is seen as an important source of competitive advantage. Now it is possible to challenge traditional approaches to inventory management. In the past, one of the de-facto assumptions for inventory management was that the demand pattern follows a specific distribution function. However, it is undesirable to apply this assumption in real situations because the demand information in the supply chain tends to be distorted due to the bullwhip effect in a supply chain. To overcome this weakness, we propose a new solution method using NN (Neural Network). Our method proceeds in three steps. First, we find the patterns of optimal reorder points by analyzing past data. Second. train the NN using these pattern data and finally decide the reorder point. Using simulation experiment, we show that the proposed solution method gives better result than that of traditional research.

• 무역상무연구
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• 제64권
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• pp.239-264
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• 2014

Two types of responses to climate change exist. First is climate mitigation which includes efforts of reducing CO2 and GHG emissions. Second response is climate adaptation process which is establishing climate resilience in the supply chain. The two are inherently different since mitigation strategy focus on eliminating the source of climate change and is long term in nature but adaptation strategy is moderating the impact of potential or current climate change. In order to embed climate resilience in the supply chain, mitigation strategies and adaption strategies must be implemented simultaneously. Corporation's adaptation to climate change related natural disaster can be seen as a response that includes mitigation and adaptation strategies simultaneously. A comprehensive climate change resilience supply chain approach has to be developed. This paper illustrated guidelines and adaptation process framework businesses can utilize in order to build climate resilience. Screening process before the actual assessment of risk was introduced as well as the whole adaptation process of establishing information system and strengthening climate-related operational flexibility.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.606-611
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• 2018

산업현장과 열병합발전 등 다양한 장소에 사용되는 도시가스는 산업안전보건법 정의에 따라 인화성 가스에 해당되며 한국산업표준 KS C IEC에 의해 가스 폭발위험장소가 설정되어 안전하게 관리가 되어야 한다. 본 연구에서는 일반 화학공장에 적용되는 KS C IEC 표준을 저압 도시가스 사용설비 폭발위험성 예측에 합리적으로 적용하기 위해누출공 크기, 환기 등급, 환기 유효성 등의 주요 변수를 도입하였다.CFD 시뮬레이션 적용의 타당성을 평가하기 위해 전산유체역학 (CFD) 시뮬레이션, 가스누출실험, KS C IEC 표준 계산 통해 얻어진 폭발하한계가상 체적을 이용하여 네 가지 다른 조건에서 폭발 위험성을 평가하였다.