• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.190-190
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• 2016

The Water, Energy, and Food (WEF) nexus is an emerging concept for sustainable resources planning and management. The three valuable resources are inevitably interconnected, that is, it takes water to produce energy; it takes energy to extract, treat, and distribute water; and both water and energy are required to produce food. Although it is challenging to fully understand the complicated interdependency, a few studies have been devoted to interpret the concept and develop the assessment tools. The tools were mainly developed for nation-wide simulations without considering inter-basin or inter-state resources trade. This study tries to present an idea to develop and implement the WEF nexus simulation model in regional scale by advancing the existing nation-wide model with additional capability to simulate the inter-basin trade. This simulation could help local planners and engineers to determine optimal policies and infrastructure solutions to reach and ensure local demand satisfaction. The simulation model is implemented in hypothetical areas with different conditions of WEF demands and supplies. Although the inter-basin trade scenarios are simulated manually, it shows that the inter-basin resources trade could enhance the resources security for a longer time period. In future, an optimization model might be developed to provide the automatic calculation to reach optimum amount of WEF for the trade, which can be a helpful tool in decision making process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1080-1089
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• 1999

The union upper bounds to the bit error probability of maximum likelihood(ML) soft-decoding of parallel concatenated convolutional codes(PCCC) and serially concatenated convolutional codes(SCCC) can be evaluated through the weight enumerating function(WEF). This union upper bounds become the lower bounds of the BER achievable when iterative decoding is used. In this paper, to compute the WEF, an efficient error event search algorithm which is a combination of stack algorithm and bidirectional search algorithm is proposed. By computor simulation, it is shown that the union boounds obtained by using the proposed algorithm become the lower bounds to BER of concatenated convolutional codes with iterative decoding.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.163-163
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• 2019

The rapidly growing global population increases the awareness of water, energy, and food security worldwide. The concept of Water, Energy, and Food nexus (hereafter, WEF nexus) has been widely introduced as a new resources management concept that integrate the water, energy, and food in a single management framework. Recently, WEF nexus analyzes not only the interconnections among the resources, but also considers the external factors (such as environment, climate change, policy, finance, etc) to enhance the resources sustainability by proper understanding of their relations. A nation-level resources management is quite complex task since multiple regions (e.g., watersheds, cities, and counties) with different characteristics are spatially interconnected and transfer the resources each other. This study proposes a multiple region WEF nexus simulation and transfer model. The model is equipped with three simulation modules, such as local nexus simulation module, regional resources transfer module, and optimal investment planning module. The model intends to determine an optimal capital investment plan (CIP), such as build-up of power plants, water/waste water treatment plants, farmland development and to determine W-E-F import/export decisions among areas. The objective is to maximize overall resources sustainability while minimize financial cost. For demonstration, the proposed model is applied to a semi-hypothetical study area with three different characterized cities. It is expected the model can be used as a decision support tool for a long-term resources management planning process.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.409-409
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• 2019

개발도상국 중심의 전 세계인구 증가추세와 도시화 현상, 경제발전 등의 요인으로 자원 수요량이 꾸준히 증가하고 있으며 글로벌 자원전쟁 및 기후변화는 자원 확보 및 활용에 대한 불확실성을 가중시키고 있다. 특히 필수자원인 물, 에너지 그리고 식량은 서로 밀접한 연관성 (Interconnection)으로 인해 각 자원 간의 상호의존성(Interdependence), 상충관계(Trade-off), 시너지(Synergy)가 존재한다. 이를 인식하고 관련 데이터베이스를 구축하여 통합적인 관점에서 분석하는 것이 물-에너지-식량 넥서스(Water-Energy-Food Nexus, WEF Nexus)이다. 현재 해외에서는 WEF Nexus에 대한 정의를 정립하고 적용방안에 대한 연구가 활발히 진행 중이다. 하지만 국내 연구는 대부분 개념과 필요성 제시에 불과하며, 정량적인 방법들에 대한 분석은 부족한 실정이고, 다양한 적용방안에 대한 연구는 초기 단계에 불과하다. 이에 본 연구는 국내외 WEF Nexus에 대한 정량적 가치평가 연구들을 조사 분석하여, 국내 적용 시의 문제점 및 시사점을 제시하고자 한다. 국외에서도 전력, 양수발전, 소규모 수력발전, 원예, 도시농업 등 다양한 분야에서 WEF Nexus 접근방식을 통한 연구들이 진행되고 있으나 실제 구체적이고 명확한 방식에 의해 정량적 가치를 도출한 사례는 많지 않은 실정이다. 그러나 넥서스 접근방법의 긍정적 효과를 제시하기 위해서는 이와 같은 정량적 분석이 시급이 필요한 시점이다. WEF Nexus 접근법을 국내에 성공적으로 적용시키기 위해서는 (1) 자원별 데이터베이스 구축 (2) 다양한 다양한 평가 툴 개발 및 적용 (3) 자원간 통합적 접근 방안이 필요하다. 이러한 과정들 하나하나가 현실적이고 구체화하기 위해서는 아직까지 많은 시행착오가 필요할 것으로 보인다. 본 연구에서는 국제사회에서 제한적으로 적용된 다양한 정량화 방안들을 검토하고 국내 적용을 위해서 어떠한 사항들이 필요하고 구축되어야 하는지 제시하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.292-292
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• 2022

가뭄은 사회기반시설, 인적 자본 등과 같은 자산에 직접적인 영향을 미치지 않으나 물을 중요한 투입재로 사용하는 농업부문에 피해가 집중된다. 가뭄 재해는 준비와 대응에 따라 피해에 큰 차이가 크기 때문에 다른 재해와는 달리 강도뿐만 아니라 지속기간을 고려해야 한다. 효과적인 가뭄 위험 관리를 위해서는 가뭄의 특징과 가뭄 준비 및 대응 수단에 따른 환경 및 경제적 영향을 평가할 수 있는 모형 구축과 다양한 농업자원을 동시적으로 연계 평가하여 지속가능성을 판단할 수 있는 기술 개발이 필요하다. 이에 본 연구에서는 기후변화 등의 외부요인을 반영한 물-에너지-식량 (Water-Energy-Food, WEF) 넥서스 기반 농업 가뭄 평가 플랫폼 설계를 제안하고자 한다. 이를 위해 물-에너지-식량 넥서스 연계 해석 고도화 기술을 개발하고, 생물-물리학적 모델 및 경제학적 모델 연계형 기후-토양-물-에너지-식량 넥서스 (CS-WEF NEXUS) 플랫폼을 구축하여, 최종적으로 기후변화 및 농업부문 가뭄 준비 및 대응 수단의 영향 평가를 바탕으로 한 의사결정 지원 도구를 제시하는 것이 최종 목표이다. 본 연구에서 구축된 플랫폼은 넥서스 연계 해석을 통해 농업 가뭄 대응을 위한 식량 및 에너지 안보 정책에도 미칠 수 있는 영향을 분석할 수 있으며, 다양한 식량-물-에너지 정책들이 타 요소들에 미치는 영향을 쉽게 평가할 수 있다는 점에서 정책적 의사결정 지원 시스템으로서 활용도가 높을 것으로 예상한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.43-47
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• 2000

In regions of low signal-to-noise ratio (SNR), performance analysis uses simulations of hybrid concatenated coding systems. However, for higher SNR regions beyond simulation capabilities, average upper bounds to bit error rate (BER) and word error rate (WER) are used. In [1], all weight enumerating functions are needed to obtain average bounds. In this paper, we use RSC as constituent codes, by using effective free distances instead of WEF, we derive average BER and WER bounds of hybrid concatenated convolutional codes (HCCC) and analyze the BER and WER over AWGN and Rayleigh/Rician fading channels.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.104-113
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• 2017

K. Suwab, a chairman of the World Economic Forum (WEF), reported the emerging of the $4^{th}$ industrial revolution by the convergence of artificial intelligence and robot as well as the fusion of true and virtual reality in the WEF 2016. He suggested the $4^{th}$ industrial revolution would change greatly the paradigm of industry and society in the future, and damage the security and quality of the human job severely. In this review the argument of terminology, the impacts on economics, industry technologies and jobs by the $4^{th}$ industrial revolution have been discussed. And the role of magnetics on the 2-4th industrial revolutions was reviewed briefly.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.153-153
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• 2018

Water-Energy-Food (WEF) nexus is a new holistic resources management concept that considers the interconnections among resources for sustainable resources planning and management. The current challenge is to fulfill the required demand in the lack of available resources. A traditional way to provide more available resource is by increase in production, but it caused increment of indirect demand of other interlinked resources. Importing resources from other area (where local supply is redundant) is another option to secure local resources with additional economic expenditure. The WEF nexus-trading model adapts the previously developed nationwide nexus simulation model with additional input parameters and functions to simulate trading scenarios. In general, the analysis starts with the quantification of local resources deficit (potential importing amount) and redundancy (potential exporting amount) of each area. Then, a trade module is initiated by determining possible donor area and importation amount. Finally, the nexus simulation for all area is re-run to determine final resources supply-demand results including the trading amount. The trade option provides an opportunity to meet local demands without draining local resources. However, the production capability of donor area may limit the importation amount. The newly developed trade option allows more alternatives for stakeholders to determine resources management plans.

• 한국상하수도협회지
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• s.5
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• pp.126-135
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• 2004

• Magazine of the Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.33-38
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• 2018