• 한국농공학회논문집
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• 제57권5호
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• pp.113-122
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• 2015

This study aims to evaluate future stream flow by the operation of agricultural reservoir group at the upper stream of the Miho River. Four agricultural reservoirs with storage capacities greater than one million cubic meters within the watershed were selected, and the RCP 8.5 climate change scenario was applied to simulate reservoir water storage and stream flow assuming that there are no changes in greenhouse gas reduction. Reservoir operation scenarios were classified into four types depending on the supply of instream flow, and the water supply reliability of each reservoir in terms of water supply under different reservoir operation scenarios was analyzed. In addition, flow duration at the watershed outlet was evaluated. The results showed that the overall run-off ratio of the upper stream watershed of the Miho River will decrease in the future. The future water supply reliability of the reservoirs decreased even when they did not supply instream flow during their operation. It would also be difficult to supply instream flow during non-irrigation periods or throughout the year (January-December); however, operating the reservoir based on the operating rule curve should improve the water supply reliability. In particular, when instream flow was not supplied, high flow increased, and when it was supplied, abundant flow, ordinary flow, and low flow increased. Drought flow increased when instream flow was supplied throughout the year. Therefore, the operation of the agricultural reservoirs in accordance with the operating rule curve is expected to increase stream flow by controlling the water supply to cope with climate change.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.99-99
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• 2009

Two different micro-flows during the evaporation of ink droplets were achieved by engineering both surface tension gradient and compositional gradient across the ink droplet: (1) Coffee-ring generating flow resulting from the outward flow inside the ink droplet & (2) Marangoni flow leading to the circulation flow inside the ink droplet. The surface tension gradient and the compositional gradient in the ink droplets were tailored by mixing two different solvents with difference surface tension and boiling point. In order to create the coffee-ring generating flow (outward flow), a single-solvent system using N,N-dimethylformamide with nano-sized spherical alumina particles was formulated, Marangoni flow (circulation flow) was created in the ink droplets by combining N,N-dimethylformamide and fotmamide with the spherical alumina powders as a co-solvent ink system. We have investigated the effect of these two different flows on the formation of ceramic films by inkjet printing method, The packing density of the ceramic films printed with two different ink systems (single- and co-solvent systems) and their surface roughness were characterized. The dielectric properties of these inkjet-printed ceramic films such as dielectric constant and dissipation factor were also studied in order to evaluate the feasibility of their application to the electronic ceramic package substrate.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.109-111
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• 2015

The Arctic transportation offers big opportunities as shorter transport distances, less fuel consumption, less carbon emissions, faster deliveries of goods, and more profits. The present study is aimed to investigate a future flow to deal with policy in arctic transportation using Big data analysis.

• 한국의류학회지
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• 제33권9호
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• pp.1409-1418
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• 2009

This study investigates the relationship among interactivity, telepresence, flow, and future behavior intention in internet shopping. Respondents were female consumers age 20 to 30. These consumers are regarded to have experience in internet shopping. 500 samples were used in this research. For data analysis, descriptive statistics, factor analysis, ANOVA, and multiple regression analysis were used for this study. As the result, interactivity, telepresence, and flow affect future behavior intention. Flow is the most influential variable affecting the future behavior intention. It implies that hedonic shopping experience (aroused by flow) can increase the future behavior intention of consumers. Consumers can operate and change the product image with convenience by encouraging interactivity between the internet fashion shopping mall and consumers. Through the technology, the experience 'flow' of consumers can provide a sense of telepresence as if they were shopping in a real store. Consumers may feel unconscious of the passage of time and feel fun, free, and original. Therefore, the internet shopping mall should pay attention to what customers demand and reflect it through e-mail, real time chatting, and text messages. In addition, rich product information such as detailed images should be supplied to help customers visualize looks.

• 전자공학회논문지
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• 제50권1호
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• pp.34-45
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• 2013

최근 국내외에서는 새로운 네트워크 구조 및 프로토콜에 대한 연구 활동이 활발하게 진행되고 있으며, 이러한 연구활동 지원을 위한 테스트베드 및 관련 기술에 대한 연구 활동이 활발히 진행되고 있다. 국내에서는 OpenFlow 프로토콜 기반의 미래 인터넷 테스트베드 구축과 연구자들에게 독립적인 연구 공간 제공을 위한 네트워크 가상화 기술에 관한 연구가 함께 진행되고 있다. 네트워크 가상화는 많은 연구자들이 테스트베드를 공유하면서 각각의 연구에 대해 서로 영향을 주지 않고 테스트 베드 활용을 극대화하는 기술이다. 본 논문에서는 수락 제어 및 사용자의 최소 대역폭 보장을 제공하는 QoS기능을 포함하는 Enhanced FlowVisor를 구현하였다. 또한, OpenFlow 프로토콜 기반의 미래인터넷 테스트베드에서 Enhnaced FlowVisor의 성능 검증을 위한 실시간 비디오 스트리밍 실험을 수행 하였으며, 실험을 통하여 미래인터넷 테스트베드의 가상화된 네트워크에 각각의 연구들에게 서로의 트래픽 간섭없이 신뢰있고 안정적인 QoS 보장을 제공할 수 있음을 확인하였다.

• 한국병원경영학회지
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• 제11권3호
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• pp.19-41
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• 2006

The Objective of this study was to design the model which predict the future cash flow of hospitals and on the basis of designed model to support sound hospital management by the prediction of future cash flow. The five cash flow measurement variables discussed in financial accrual part were used as variables and these variables were defined as NI, NIDPR, CFO, CFAI, CC. To measure the cash flow B/S related variables, P/L related variables and financial ratio related variables were utilized in this study. To measure cash flow models were designed and to estimate the prediction ability of five cash flow models, the martingale model and the market model were utilized. To estimate relative prediction outcome of cash flow prediction model and simple market model, MAE and MER were used to compare and analyze relative prediction ability of the cash flow model and the market model and to prove superiority of the model of the cash flow prediction model, 32 Regional Public Hospital's cross-section data and 4 year time series data were combined and pooled cross-sectional time series regression model was used for GLS-analysis. To analyze this data, Firstly, each cash flow prediction model, martingale model and market model were made and MAE and MER were estimated. Secondly difference-test was conducted to find the difference between MAE and MER of cash flow prediction model. Thirdly after ranking by size the prediction of cash flow model, martingale model and market model, Friedman-test was evaluated to find prediction ability. The results of this study were as follows: when t-test was conducted to find prediction ability among each model, the error of prediction of cash flow model was smaller than that of martingale and market model, and the difference of prediction error cash flow was significant, so cash flow model was analyzed as excellent compare with other models. This research results can be considered conductive in that present the suitable prediction model of future cash flow to the hospital. This research can provide valuable information in policy-making of hospital's policy decision. This research provide effects as follows; (1) the research is useful to estimate the benefit of hospital, solvency and capital supply ability for substitution of fixed equipment. (2) the research is useful to estimate hospital's liqudity, solvency and financial ability. (3) the research is useful to estimate evaluation ability in hospital management. Furthermore, the research should be continued by sampling all hospitals and constructed advanced cash flow model in dimension, established type and continued by studying unified model which is related each cash flow model.

• 한국정보과학회논문지:정보통신
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• 제41권4호
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• pp.167-176
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• 2014

본 논문은 이동 환경 위주의 미래 인터넷 환경을 위해 제안된 Mobile Oriented Future Internet (MOFI) 구조에 대하여 OpenFlow 기반 구현 이슈와 KOREN 실험망을 이용한 성능 분석을 논의한다. MOFI 구조는 호스트 식별자(host identifier)와 지역 위치자(local locator) 사용, 데이터 전달을 위한 Query 우선의 데이터 전달(Query-First Data Delivery), 식별자와 위치자간 분산형 매핑 시스템(Distributed Mapping System)을 특징으로 한다. 기존 MOFI 연구에서는 intra-domain 이동성 지원을 위해 6-to-4 터널링 기법 및 리눅스 플랫폼을 활용한 구현 방식을 제안하고 실험실 테스트베드에서 성능분석을 수행하였다. 한편, 본 논문에서는 inter-domain 이동성 지원을 위한 세부 절차를 논의하고 Click Modular Router와 OpenFlow 플랫폼을 활용한 MOFI 구현 방식을 제안한다. 나아가, 실제 KOREN 실험망을 활용한 성능 실험을 통해 MOFI 구조와 기존 이동성 제어 방식인 Proxy Mobile IP (PMIP) 기법을 비교한다. 실험 결과, 이동성 제어를 위한 시그널링 지연 시간 및 처리되는 메시지 수 측면에서 MOFI 구조가 기존 PMIP 이동성 제어 기법에 비하여 더 좋은 성능을 보이고 있음을 확인하였다.

• 대한전자공학회논문지TC
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• 제47권7호
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• pp.118-127
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• 2010

패킷 기반의 TCP/IP 프로토콜 기반으로 구축된 인터넷 환경은 30년 넘게 사용되어 왔으나, 향후 통신환경의 급격한 변화와 다양한 사용자 요구사항의 증대로 인해 프로토콜 확장의 제약으로 인한 근본적인 문제점을 나타나게 될 것이다. 이를 해결하기 위해 Clean Slate 설계 방법에 기반을 둔 미래인터넷 연구가 진행되고 있고, 이를 실험하고 검증하기 위한 대규모 테스트베드 구축이 이루어질 것이다. 이를 위한 오픈 플로우 스위치 기술은 기존에 포설된 네트워크 장비를 활용하면서, 인터넷 트래픽에 영향을 주지 않고 독립적인 프로토콜을 시험할 수 있도록 하는 새로운 기술로 제안되었다. 국내에서도 테스트베드 구축의 한 방법으로 NetFPGA기반 오픈 플로우 스위치를 활용한 망구성이 연구되고 있으며 이러한 구조에서 인터넷망을 통한 오픈플로우 스위치 간 연결이 이루어지기 위해서는 오픈 플로우 스위치 간 논리적인 터널링이 제공되어야 한다. 이에 대한 해결책으로 본 논문에서는 NetFPGA 기반의 캡슐레이터를 구현하여 국내연구망인 KOREN에 구현된 여러 오픈 플로우 사이트 간에 MAC in IP 터널링이 이루어 질 수 있도록 하였고 이의 성능을 측정하였다. 측정 결과 기존 소프트웨어 기반의 캡슐레이터에 비해 성능이 향상되었음을 확인하였고, 미래인터넷 기술을 실험할 수 있는 테스트 베드로 활용할 수 있음을 보였다.

• 수산경영론집
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• 제40권1호
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• pp.51-74
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• 2009

The purpose of this study is to ascertain that how the futures market of the Japanese frozen shrimp that is the only fisheries asset all over the world can be efficient. Accordingly, this paper examines efficiency and information flow of the Japanese frozen shrimp market using data from Kansai Commodities Exchange frozen shrimp futures closing prices and spot prices. And then this paper estimates a forward price model using that data. From the model, risk premium is estimated and we could also analyse the future information flow into the futures market which reveals future spot prices. This thesis reached to conclusions as follows: First, the null of zero risk premium is rejected and the value of that is negative. Second, the time pattern of information flow into the futures market is that most of the information on future price arrives within a week and for the last week, most of relevant information is already incorporated. The result of this study contrasts with that of Stockman(1978) about currency futures market of U.S.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.2-4
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• 2010

Due to rapid progress in the performance of high-end computers, numerical prediction of fluid flow and flow-induced sound is expected to become a vital tool for aero- and hydro- dynamic design of various flow-related products. This presentation focuses on the applications of large-scale numerical simulations to complex engineering problems with a particular emphasis placed on the low-speed flows. Flow field computations are based on a large eddy simulation that directly computes all active eddies in the flow and models only those eddies responsible for energy dissipations. The sound generated from low-speed turbulent flows are computed either by direct numerical simulation or by decoupled methods, according to whether or not the feedback effects of the generated sound onto the source flow field can be neglected. Several numerical examples are presented in order to elucidate the present status of such computational methods and discussion on the future prospects will also be given.