• 한국수자원학회논문집
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• 제46권4호
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• pp.373-387
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• 2013

수자원시스템의 효율적인 운영 및 관리를 위해서는 하천 시설물들을 효율적으로 연계운영 할 필요가 있다. 그러나 이를 위한 시뮬레이션 모형은 최선의 대안을 보장하지 못하고, 최적화 모형은 복잡한 수계 현황을 유연하게 고려하는데 어려움이 있다. 따라서 시뮬레이션과 최적화 기법의 한계점을 서로 보완해서 활용하는 것이 바람직하다. 이에 본 연구에서는 시뮬레이션과 최적화 기법의 원론적 비교를 통해 각 기법의 장 단점을 분석하고, 두 방법의 한계점을 극복할 수 있는 시뮬레이션 기반의 최적화 모형, CoWMOM의 활용을 제안한다. 아울러 댐-보 연계운영 모형의 활용방안으로 i) 과거의 특정 기간에 대한 분석 도구로써의 활용법과, ii) 미래 수문 정보가 불확실한 상황에서 댐-보 연계운영을 하는 현실에 적합한 모형 활용 절차를 제시한다.

• 한국통신학회논문지
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• 제34권2A호
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• pp.99-106
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• 2009

본 논문에서는 OFDMA(Orthogonal Frequency Division Multiplex Access) 기반 셀룰러 시스템에 셀 간 간섭회피 및 제거 기법을 적용하기 위한 UCA(UIIM Channel Algorithm) 알고리즘을 제안한다. 3가지 주파수 설계 방식 하에 서로 다른 2가지 UCA 알고리즘으로 단말에 주파수를 할당하는 방법들의 성능을 살펴본다. 제안한 UCA 알고리즘은 홈 섹터와 인접 섹터에서 전송된 수신 신호 파워 정보를 사용한다. 모의실험을 통해서 모든 UCA 알고리즘과 주파수 설계의 조합을 비교한다. 주된 비교 수단은 하위 5% 단말 데이터 신호대 간섭 및 잡음비이다. 제안한 UCA 알고리즘은 셀 안쪽에 위치한 단말에게는 상대적으로 낮은 파워를 할당하여 인접 셀에 유도되는 간섭을 회피하고 심벌 반복을 통하여 셀 외곽에 위치한 단말에 대한 간섭을 완화시킨다. 주파수 설계 1을 적용한 UCA 알고리즘 2가 하위 5% 단말 데이터 신호대 간섭 및 잡음비 면에서 다른 경우들에 비해 좋은 성능을 보인다.

• 한국건설관리학회논문집
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• 제5권1호
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• pp.124-132
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• 2004

대부분 국내 건설현장의 인력관리는 협력업체별 당일 출역현황만을 관리하고 있다. 그러나 이와 같은 인력관리 방법은 적정투입 인력 및 생산성 확인, 계획대비 실투입 인력의 오차를 명확히 파악할 수 없기 때문에 이로 인해 발생하는 공기지연을 사전에 예방할 수 없는 한계를 가지고 있다. 이는 건설현장에서 공정계획과 인력자원이 상호 유기적으로 연계된 관리 노력의 부재에 그 원인이 있다. 따라서 건설현장의 공정관리 능력향상을 통하여 공정계획을 기반으로 한 체계적인 협력업체 인력관리의 필요성이 요구된다. 본 고에서는 CPM 공정표에 인적자원을 연계하여 관리할 수 있는 변혁 프로그램으로써 일일공정 Check System을 개발하였다. 또한 실제 공사 중인 아파트현장의 골조공사에 이를 적용하여 본 시스템의 활용 타당성과 효과를 검증하였다.

• 교육시설 논문지
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• 제20권2호
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• pp.33-42
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• 2013

Due to the lack of available site in urban setting outdoor space in elementary schools are getting smaller and tend to be replaced by indoor spaces. Focusing on courtyard, piloti space and roof space, this study analyzed the current condition and usage of the outdoor spaces in the urban mini-schools based on the analysis of architectural drawing, interview, survey, and observation. Following issues are found for appropriate planning for outdoor spaces in the urban mini-schools. Firstly, roof space needs to be coordinated with the physical education and outdoor class curriculum and should be planned separately for quiet activities. Secondly, the piloti space should be planned as an independent space rather than a connection between classroom and outdoor space, with appropriate surveillance from teacher's space for the lower graders. Thirdly, courtyard space, typical space in urban mini school surrounded by densely arranged buildings, should be thermally controlled for outdoor class or resting with appropriate screen from noise to keep quiet atmosphere.

• 산업공학
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• 제13권3호
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• pp.424-430
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• 2000

Supply chain management (SCM) is an area that has recently received a great deal of attention in the business community. While SCM is relatively new, the idea of coordinated planning is not. During the last decades, many researchers have investigated multi-stage inventory problems. However, only a few papers address the problem of cost-optimal coordination of multi-stage inventory control with respect to service measures. Even published approaches have a shortcoming in dealing with a delivery lead time consisted of a shipping time and a waiting time. Assumed that there is no waiting time, or that the delivery lead time is implicitly compounded of a shipping time and a waiting time, the problem is often simplified into a multi-stage buffer allocation and a single-stage stochastic buffer sizing problem at all installations. This paper presents a simulation-based heuristic algorithm and a comparison with others for the problem that cannot be decomposed into a multi-stage buffer allocation and a single-stage stochastic buffer sizing problem because the waiting time ties together all stages. The comparison shows that the simulation-based heuristic algorithm performs better than other approaches in saving average inventory cost for both Poisson and Normal demands.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.2982-3003
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• 2014

With the explosive deployment of the wireless communications technology, the increased QoS requirement has sparked keen interest in network planning and optimization. As the major players in wireless network optimization, the BS's resource utilization and mobile user's QoS can be improved a lot by the load-balancing technology. In this paper, we propose a load-balancing strategy that uses Coordinated Multiple Points (CoMP) technology among the Base Stations (BS) to effectively extend network coverage and increase edge users signal quality. To use universally, different patterns of load-balancing based on CoMP are modeled and discussed. We define two QoS metrics to be guaranteed during CoMP load balancing: call blocking rate and efficient throughput. The closed-form expressions for these two QoS metrics are derived. The load-balancing capacity and QoS performances with different CoMP patterns are evaluated and analyzed in low-dense and high-dense traffic system. The numerical results present the reasonable CoMP load balancing pattern choice with guaranteed QoS in each system.

• 한국농공학회논문집
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• 제57권2호
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• pp.1-13
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• 2015

The Coupled Model Intercomparison Project Phase 5 (CMIP5), coordinated by the World Climate Research Programme in support of the Intergovernmental Panel on Climate Change (IPCC) AR5, is the most recent, provides projections of future climate change using various global climate models under four major greenhouse gas emission scenarios. There is a wide selection of climate models available to provide projections of future climate change. These provide for a wide range of possible outcomes when trying to inform managers about possible climate changes. Hence, future agrometeorological indicators estimation will be much impacted by which global climate model and climate change scenarios are used. Decision makers are increasingly expected to use climate information, but the uncertainties associated with global climate models pose substantial hurdles for agricultural resources planning. Although it is the most reasonable that quantifying of the future uncertainty using climate change scenarios, preliminary analysis using reasonable factors for selecting a subset for decision making are needed. In order to narrow the projections to a handful of models that could be used in a climate change impact study, we could provide effective information for selecting climate model and scenarios for climate change impact assessment using maximum/minimum temperature, precipitation, reference evapotranspiration, and moisture index of nine Representative Concentration Pathways (RCP) scenarios.

• 산업공학
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• 제23권4호
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• pp.311-318
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• 2010

In the daily multi-reservoir operating problem, monthly storage targets can be used as principal operational guidelines. In this study, we tested the use of a simple back-propagation Artificial Neural Network (ANN) model to derive monthly storage guideline for daily Coordinated Multi-reservoir Operating Model (CoMOM) of the Han-River basin. This approach is based on the belief that the optimum solution of the daily CoMOM has a good performance, and the ANN model trained with the results of daily CoMOM would produce effective monthly operating guidelines. The optimum results of daily CoMOM is used as the training set for the back-propagation ANN model, which is designed to derive monthly reservoir storage targets in the basin. For the input patterns of the ANN model, we adopted the ratios of initial storage of each dam to the storage of Paldang dam, ratios of monthly expected inflow of each dam to the total inflow of the whole basin, ratios of monthly demand at each dam to the total demand of the whole basin, ratio of total storage of the whole basin to the active storage of Paldang dam, and the ratio of total inflow of the whole basin to the active storage of the whole basin. And the output pattern of ANN model is the optimal final storages that are generated by the daily CoMOM. Then, we analyzed the performance of the ANN model by using a real-time simulation procedure for the multi-reservoir system of the Han-river basin, assuming that historical inflows from October 1st, 2004 to June 30th, 2007 (except July, August, September) were occurred. The simulation results showed that by utilizing the monthly storage target provided by the ANN model, we could reduce the spillages, increase hydropower generation, and secure more water at the end of the planning horizon compared to the historical records.

• 한국기후변화학회지
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• 제8권3호
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• pp.239-245
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• 2017

This study aimed to suggest priority for developing emission factor (EF) and to develop the methodology of quantitative assessment of EF in the forestry sector. Based on the stock-difference method, 17 kinds of EFs (27 EFs based on forest types) were required to calculate the carbon emission in the forestry sector. Priority for developing EFs followed the standards, which is a development plan by the government agency, importance of carbon stock for greenhouse gas, and EFs by the species. Currently, the most urgent development of EFs was carbon fraction in biomass and carbon stock in dead wood. Meanwhile, the quantitative assessment of EF consisted of 7 categories (5 categories of compulsory and 2 categories of quality evaluation) and 12 verification factors. Category in compulsory verification consisted of administrative document, determination methodology of emission factors, emission characteristic, accuracy of measurement and analysis, and data representative. Category in quality evaluation consisted of data management and uncertainty estimates. Based on the importance of factors in the verification process, each factor was scored separately, however, the score needs to be coordinated by the government agency. These results would help build a reliable and accurate greenhouse gas inventory report of Korea.

• 한국물환경학회지
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• 제38권4호
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• pp.177-189
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• 2022

Nature-based Solutions (NbS) are defined as practical and technical approaches to restoring functioning ecosystems and biodiversity as a means to address socio-environmental challenges and provide human-nature co-benefits. This study reviews NbS-related literature to identify its key characteristics, techniques, and challenges for its application in climate-adaptive water management. The review finds that NbS has been commonly used as an umbrella term incorporating a wide range of existing ecosystem-based approaches such as low-impact development (LID), best management practices (BMP), forest landscape restoration (FLR), and blue-green infrastructure (BGI), rather than being a uniquely-situated practice. Its technical form and operation can vary significantly depending on the spatial scale (small versus large), objective (mitigation, adaptation, naturalization), and problem (water supply, quality, flooding). Commonly cited techniques include green spaces, permeable surfaces, wetlands, infiltration ponds, and riparian buffers in urban sites, while afforestation, floodplain restoration, and reed beds appear common in non- and less-urban settings. There is a greater lack of operational clarity for large-scale NbS than for small-scale NbS in urban areas. NbS can be a powerful tool that enables an integrated and coordinated action embracing not only water management, but also microclimate moderation, ecosystem conservation, and emissions reduction. This study points out the importance of developing decision-making guidelines that can inform practitioners of the selection, operation, and evaluation of NbS for specific sites. The absence of this framework is one of the obstacles to mainstreaming NbS for water management. More case studies are needed for empirical assessment of NbS.