• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.147-147
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• 2021

A partition of water distribution network (WDN) into district metered areas (DMAs) brings the efficiency and efficacy for water network operation and management (O&M), especially in monitoring pressure and leakage. Traditionally, the DMA configurations (i.e., number, shape, and size of DMAs) are permanent and cannot be changed occasionally. This leads to changes in water quality and reduced network redundancy lowering network resilience against abnormal conditions such as water demand variability and mechanical failures. This study proposes a framework to automatically divide a WDN into dynamic DMA configurations, in which the DMA layouts can self-adapt in response to abnormal scenarios. To that aim, a complex graph theory is adopted to sectorize a WDN into multiscale DMA layouts. Then, different failure-based scenarios are investigated on the existing DMA layouts. Here, an optimization-based model is proposed to convert existing DMA layouts into dynamic layouts by considering existing valves and possibly placing new valves. The objective is to minimize the alteration of flow paths (i.e., flow direction and velocity in the pipes) while preserving the hydraulic performance of the network. The proposed method is tested on a real complex WDN for demonstration and validation of the approach.

• 웰빙융합연구
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• 제5권4호
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• pp.11-17
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• 2022

Purpose: This study discusses how Indonesia's response to the Corona Virus Disease-19 pandemic based on the perspective of housing policy capacity which consists of resources, organizations, and networks, politics, systems, and finance. Research design, data and methodology: This study used a qualitative method through a literature review. Data collection techniques were carried out by searching various sources and literature related to housing capacity theory and various data on Indonesia's response to the Covid 19 pandemic. Based on a literature review, this study adapted and modified the five components of capacity, namely resource capacity, organizational and network capacity, political capacity, system capacity and financial capacity in Indonesia in responding to the Covid-19 pandemic. Data analysis used analytical themes which consist of understanding the data, generating initial codes, looking for themes, reviewing themes, defining and naming themes, producing of manuscripts. Results: The results show that the weakness of the system capacity greatly affects Indonesia's housing policy capacity in responding to the Covid-19 pandemic and on the other hand the five housing capacities are an integrated process within the housing policy framework in Indonesia, especially to overcome the Covid-19 pandemic. Conclusions: The findings of this study are the importance of building a system capacity that is directly integrated with housing policy and the strengthening of the resources capacity, organizations, and networks, politics, and finance in the context of Indonesia's housing policy, especially in dealing with the Covid-19 pandemic situation.

• 태양에너지
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• 제10권1호
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• pp.47-56
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• 1990

수직축 다리우스 풍력 터어빈의 공기역학적 특성을 해석코자 날개요소이론과 운동량 이론에 근거하는 이중다류관모델을 정립하여 모델풍동실험과 병행하여 비교분석하였다. 이중 다류관 모델은 아직 수정 보완의 여지는 있으나 터어빈을 통과하는 유동의 변화가 심하지 않은 날개끝속도비나 회전면적비가 작은 경우에는 비교적 정확히 터어빈의 공기역학적 특성을 예측함을 알 수 있었고, 모형풍동실험을 통해 정확한 터어빈 회전수제어로서 각 특성변수들에 대한 영향을 살피었다. 본 연구의 결과로서는 다리우스 터어빈의 설계 및 운전특성 예측에의 응용이 기대될 수 있다.

• 대한가정학회지
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• 제44권4호
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• pp.23-38
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• 2006

The purpose of this study was to investigate the strengths of single-parent families and the related variables based on the family strength approach. The major findings were as follows. First, good communication, family bond, children's adjustment and coping ability were characteristics of single-parent family strengths. Secondly, strengths of single-parent family were related to income and period of becoming a single-parent family. Thirdly, single parents who had a higher level of personal resources such as high self-esteem and economic stability perceived a higher level of family strengths. Fourth, single parents who had a higher level of social support perceived a higher level of family strength. Fifth, there was no interaction effect between personal resource and social resource on single-parent family strengths. Last, both personal and social resources had effects on the strength of single- parent family. Especially personal resource and self-esteem were the most important variables and had a strong influence on single-parent family strengths. The results of this study have important implications for theory, research and practice. Research on the strengths of the Korean single-parent family is new and more extensive investigation is required.

• 한국수자원학회논문집
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• 제50권9호
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• pp.647-652
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• 2017

우리나라 해안지역에는 많은 섬들이 위치하고 있어 대규모 지진해일이 발생하였을 때 섬과 지진해일의 상호작용으로 예기치 않은 지진해일 피해가 우려된다. 2011년 발생한 동일본 지진해일의 경우 제주도를 비롯한 남해안 섬들에 영향을 미쳤다. 본 연구에서는 천수이론에 근거한 수치모형을 이용하여 섬 중앙에 대하여 비대칭으로 입사하는 고립파의 처오름높이에 관하여 연구한다. 연구에서 얻은 결과는 지진해일의 급습에 대비한 방재대책을 수립하는데 사용될 수 있을 것이다.

• Journal of Korea Trade
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• 제23권3호
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• pp.38-51
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• 2019

Purpose - An appreciable number of small- and medium-sized exporters have continuously succeeded in their export marketplaces even though they do not possess enough resources. Advocating that affiliation with an export service-provider plays an important role in this phenomenon, we aimed to theoretically explain how export service providers' competences and relational factors drive small- and medium-sized exporters' competitive advantages in the long-run. Design/methodology - Drawing prominently on the resource-based view and the relationship-marketing theory, we built an empirically testable model. The model showed the roles of exporter capabilities, export service-provider competences, and relational factors on small- and medium-sized exporters' sustainable competitive advantages. Findings - The results of our research showed that exporter production and branding capabilities positively influenced their sustainable competitive advantage. In addition, export service-providers' marketing competence and relationship-building competence positively moderated the effects of exporter capabilities on their parties' sustainable competitive advantages. Finally, affiliation parties' interfirm trust and relationship commitment positively moderated the effects of export service-provider competence on the relationship between exporter capabilities and sustainable competitive advantages. Originality/value - Although prior studies have highlighted the effects of an exporter's resources on export performance, our research filled a knowledge gap of the effects of other resources on export performance. First, we proposed two types of export service-provider, competence marketing and relationship-building, influencing exporters' competitive advantage. Second, the effects of relational factors were proposed in the context of export affiliations.

• 아태비즈니스연구
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• 제11권1호
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• pp.27-44
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• 2020

Purpose - This study examines the factors that influence the performance of contract farming by agricultural cooperatives from the agency theory and resource-based view of the firm. Design/methodology/approach - This study collected 1,090 data related to a sample of contract information between agricultural cooperatives and producers from national agricultural cooperatives federation. In order to examine the performance of contract farming, we use the multiple regression analysis. Findings - Incentives may reduce agency problems by increasing producers' motivation and discouraging their opportunistic behavior. Total asset size and education expenses function like resources that lessen the risks coming from environment uncertainty, and also facilitate the contract farming between producers and agricultural cooperatives. Research implications or Originality - By analyzing the factors that influence on the performance of contract farming between producers and agricultural cooperatives, we propose that incentives, and resources may improve the performance of contract farming between agricultural cooperatives and producers. Overall, the contract farming can co-create the economic efficiency and effectiveness while minimizing risks and uncertainty.

• Ocean Systems Engineering
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• 제12권1호
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• pp.63-86
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• 2022

A refined projection-based purely Lagrangian meshfree method is presented towards reliable numerical analysis of fluid flow interactions with saturated/unsaturated porous media of uniform/spatially-varying porosities. The governing equations are reformulated on the basis of two-phase mixture theory with incorporation of volume fraction. These principal equations of mixture are discretized in the context of Incompressible SPH (Smoothed Particle Hydrodynamics) method. Associated with the consideration of governing equations of mixture, a new term arises in the source term of PPE (Poisson Pressure Equation), resulting in modified source term. The linear and nonlinear force terms are included in momentum equation to represent the resistance from porous media. Volume increase of fluid particles are taken into consideration on account of the presence of porous media, and hence multi-resolution ISPH framework is also incorporated. The stability and accuracy of the proposed method are thoroughly examined by reproducing several numerical examples including the interactions between fluid flow and saturated/unsaturated porous media of uniform/spatially-varying porosities. The method shows continuous pressure field, smooth variations of particle volumes and regular distributions of particles at the interface between fluid and porous media.

• 응용통계연구
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• 제22권1호
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• pp.41-57
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• 2009

본 논문에서는 세계 232 개국에 대한 인구, 경제 및 기타 자원에 관한 자료를 사용하여 국가의 개발정도, 인간개발지수, 경제력 그리고 OECD 가입 여부에 어떤 자원이 어떻게 영향을 미치는가를 통계적으로 고찰해보고자 한다. 여기서 사용하는 국가별 자원 자료는 연속형 자료와 이산형 자료가 혼재되어있는 혼합형이며 많은 결측값이 포함되어 있어 기존의 방법으로는 분석하는 데 한계가 있다. 이 논문에서는 시각적 방법을 동원하여 복합형 자료를 탐색하는 과정을 제시하고 이러한 방법의 한계점을 보이고자한다. 이러한 한계점을 극복하고 객관적인 판단기준을 적용하여 주어진 문제에 대한 과학적인 결론을 유도하기 위해 Shannon (1948)의 엔트로피 이론에 기본을 둔 상호정보(MI)를 활용하고자 한다. 상호정보를 추정하는 방법은 여러 가지가 있으며 각 방법에 따라 결과가 매우 다르게 나타난다. 본 논문에서는 Fayyad와 Irani (1992)의 이산화 방법을 적용하여 MI를 추정하는 방법을 적용한다. 여기서 이루어지는 모든 과정은 다차원 자료의 시각적 탐색 도구인 DAVIS (Huh와 Song, 2002)를 사용하였다.

• 한국통신학회논문지
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• 제41권8호
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• pp.954-957
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• 2016

군용 통신망의 작전상황 등에서 빠른 시간 내에 주파수 배정 문제의 해를 찾는 상황은 빈번하게 발생한다. 이때 사용되는 자원 개수를 최소화하는 것은 비용과 연관되어 중요한 문제이다. 이중 편파 안테나의 편파를 적절히 분배하면 주파수 자원 개수 성능을 최소화하는데 도움이 된다. 본 논문은 그래프의 매칭 이론을 기반으로 하여 편파와 주파수를 $O(N^2)$의 복잡도 이내에 배정하는 알고리즘을 제시한다. 제시하는 알고리즘의 해는 단일 편파 알고리즘 대비 2배에 가까운 성능개선을 보이며 이론적인 최적의 값에 근접함을 확인하였다.