결과 내 재검색





        검색결과 8

        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Waterworks facilities inevitably experience some amount of leakage even if there is a lot of investment or state-of-the-art technology that is applied such as DMA(District Metered Area) system construction, leakage detection, repair, pipe rehabilitation, etc. The primary reason is the leakage is naturally restored over time. In the UK, this restoration characteristic is defined as NRR(Natural rate of rise of leakage) and used to decision making for prioritizing active leakage control of DMAs. However, this restoration characteristic is well recognized, but researches on NRR in the water distribution system are insufficient in Korea. In this study, the estimation method of NRR was developed suitable for applicating in Korea considering of SCADA data, water infrastructure, and water usage patterns by modification of the UK's NRR method. The proposed method was applied to 9 DMAs and verified it's applicability by comparing with the other water loss performance indicators. It is expected that the proposed method can be used to support decision making for sustainable NRW(Nor-revenue water) management in the water distribution system.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pressure monitoring is expected to be expanded in a water distribution system according to accelerated development of smart water network management technologies caused by appearances of affordable digital infrastructures like computing, storage and bandwidth. However, the placement of pressure sensors has been determined by engineer’s technical decisions since there is no well-defined criteria for deciding a suitable location of pressure sensor. This study presents a placement method of pressure sensors based on the consideration of allowable error in calibrating water network analysis modeling. The proposed method is to find a minimum set of pressure sensors for achieving a reliable management of water transmissions main and increasing the efficiency of their real-time operation. In the case study in Y area’s transmission main, the proposed method shows equally distributed pressure sensors in terms of hydraulics. It is expected that the proposed method can be used to manage transmission mains stably and construct a robust real-time network analysis system as a minimal criteria.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research carried out an analysis on input cost and leakage reduction effect by leakage reduction method, focusing on the project for establishing an optimal water pipe network management system in the Taebaek region, which has been executed annually since 2009. Based on the result, optimal cost-benefit analysis models for water distribution network rehabilitation project were developed using DEA(data envelopment analysis) and multiple regression analysis, which have been widely utilized for efficiency analysis in public and other projects. DEA and multiple regression analysis were carried out by applying 4 analytical methods involving different ratios and costs. The result showed that the models involving the analytical methods 2 and 4 were of low significance (which therefore were excluded), and only the models involving the analytical methods 1 and 3 were suitable. From the result it was judged that the leakage management method to be executed with the highest priority for the improvement of revenue water ratio was installation of pressure reduction valve, followed by replacement of water distribution pipe, replacement of water supply pipe, and then leakage detection and repair; and that the execution of leakage management methods in this order would be most economical. In addition, replacement of water meter was also shown to be necessary in case there were a large number of defective water meters.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        District Metered Area (DMA) construction is one of the most cost effective alternatives for management of water loss (i.e., water leakage) and energy consumption (i.e., water pressure) in water distribution systems. Therefore, it’s being implemented to numerous new and existing water distribution systems worldwide. However, due to the complexity of water distribution systems, especially large-scale and highly looped systems, it is still very difficult to define the optimal boundary of DMAs considering all the aspects of water distribution system management requirements. In this study, a DMA design methodology (or a DMA design model) was developed with Geographic Information Systems (GIS) and hydraulic distribution system model to determine the optimal DMA boundary.
        2011.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 국내 양잠산업은 의류중심의 전통적인 양잠산업에서 기능성 양잠산업으로 변화를 꾀하고 있다. 이 런 여건변화에 대응하기 위해 2009년에 「기능성 양잠산업 육성 및 지원에 관한 법률」이 시행되어 기능 성 양잠산업 종합계획 수립 근거가 마련되었다. 기능성 양잠산업 발전을 위한 종합계획을 수립하기 위해 서는 현재 양잠산업의 실태와 문제점 파악이 선결되어야 할 것이다. 본 논문의 목적은 양잠산물의 생산· 판매구조와 산업 분야별 애로요인 및 개선사항에 제시하는데 초점이 맞추어져 있다. 본 연구의 주요 연구 내용은 양잠산물 단위당 생산액, 생산 및 소비형태, 가공업체의 원료구매 및 제품 판매구조, 양잠산물 유 형별 부가가치 발생 크기, 분야별 애로요인 및 개선사항으로 구성되어 있다.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농산물 수출잠재력이 높은 러시아국가 중에서 한국과 거리가 가깝고 수출교두보로 활용하기 에 유리한 극동러시아 지역으로의 수출사례를 분석하여 수출시장 진출의 성공가능성을 높일 수 있는 시사 점을 도출하기 위해 수행하였다. 수출사례 조사업체 수는 5개, 수출사례는 8개이며, 분석대상 품목은 김 치, 딸기, 장미, 멜론, 배, 사과 등 7개 수출품목이다. 수출 성공사례는 사전 시장조사 및 수요파악, 포장 방법 개선, 유통채널 진입 및 정착, 홍보 및 판촉활동 요인으로, 실패사례는 소비자 인지도 및 선호도 파 악 미흡, 저품위 수출 요인으로 구분하여 분석하였다.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        In order to export Korean spray roses to the China, it is needed to analyse chinese preferences, rose attributes, and purchase intentions. The purpose of this study is to present the implications on the production and distribution of roses for export by analyzing the quality preference attributes and purchase intention of Korean rose for Chinese flower experts. A survey on the preference and purchase intention of Korean flower roses by Chinese flower experts was conducted through face - to - face interviews with flower show participants in China. Approximately 100 Chinese flower experts who participated in the Flower Show in 2016 received the questionnaire, and 86 survey results could be used for analysis. Survey data were analyzed using ordered probit and bivariate probit models. As a result of an analysis, it was found that Chinese flower experts were more likely to buy Korean roses than Chinese roses even if they consider flower color, leaf shape and size and color diversity. The probability of purchasing more than twice the price was higher than that of the color diversity considering the flower shape, leaf shape and size, but the bivariate order probit model was larger than that of flowers, leaves and size, and the order of probability size was changed. In order to increase the export of Korean spray roses to the Chinese market, We need to increase Chinese experts’ preferences and satisfaction. For this purpose, it is very important to develop export varieties of roses with large flower buds and shape / coloring, and to apply the useful post-harvest technology that can extend freshness and distribution period of export roses.
        2015.02 서비스 종료(열람 제한)
        상수관망의 운영에 있어서 핵심적인 사항 중의 하나는 관망의 압력균등화이다. 관망의 압력균등화는 시간과 공간적으로 이루어져야 하며 이를 위한 대표적인 방법은 가압장을 설치하는 것이다. 가압장은 관말단에 잔류수압(Residual Pressure Head)이 부족할 것으로 예상될 경우 용수에 추가적인 에너지를 가하여 원활한 용수공급을 가능하게 하는 시설이다. 그러나 가압장에는 펌프를 사용하기 때문에 지속적인 운영비용이 발생하고 기계적인 고장에 취약한 단점을 가지고 있다. 이와 같은 가압장의 단점을 보완하기 위하여 배수관망내에 탱크(In-line Tank)를 설치하는 것이 대안이 될 수 있다. 탱크의 초기투자 비용은 가압장보다 크지만 유지비용이 적고, 고장에 따른 용수공급 중단이 될 가능성이 낮다. 또한, 관파괴에 의한 단수발생시 탱크 인접지역에 비상용수원으로 활용될 수 있다. 그러나 시설비나 부지 문제로 인하여 배수관망에 많은 수의 탱크를 설치하기는 어렵다. 이에 본 연구에서는 배수관망내 필요한 탱크의 개수에 따라 적정배치를 결정할 수 있는 방법론을 제시하였다. 즉, 예산이나 설치부지 등의 제한으로 설치가능한 탱크의 수가 결정되면 이를 최적으로 배치할 수 있는 방법론을 의미한다. 이를 위한 목적함수로 시공간적 관망내 압력 균등지표(Temporal and Spatial Pressure Evenness Index, TSPEI)를 제시하였다. TSPEI 산정은, 먼저 24시간의 Extended Period Simulation을 통하여 절점별로 압력의 일변동(일최대압력-일최소압력)을 산정하고, 두번째로 모든 절점의 압력 일변동을 합산하여 구한다. 이때 가능한 탱크 조합중 TSPEI가 가장 작은 조합이 최적조합이 된다. 제안된 방법을 샘플관망(Mays' network)을 대상으로 적용성을 검증하였다. 그 결과 설치 가능한 탱크의 수를 2개, 3개, 4개로 가정하여 각각의 경우에 대해 최적탱크조합을 산정하였으며, 각각의 탱크 조합에서 일관된 경향이 나타남을 확인하였다.