• 무역상무연구
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• 제20권
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• pp.423-440
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• 2003

The trial business of e-trade service providers for supporting small enterprises to find their markets abroad is about to begin from the end of March, 2003. The department of Industrial Resources held the "Committee of e-trade service provider selection" with professors of e-trade field, and selected three companies: ECplaza, EC21 and Tpage Global. The e-trade service providers combine the various technologies of on-line trades and off-line trades to support small enterprises with lack of marketing skills by intermediation of overseas buyers and production, registration of e-catalogs and offers, administration of inquiries, trade negotiations, and contract settlement. Prospective small enterprises with exports under US$ 5 million will be selected by 2005. The selected companies will be supported fully by the government, and will be provided with the services by the e-trade service providers. e-Trade service will be the most potential and successful ones in the future, which helps traders and organizations preparing for globalization.

• 유통과학연구
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• 제14권11호
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• pp.83-90
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• 2016

Purpose - During the last two years, convenient stores (CS) are emerging as one of the most fast-growing retail trades in Korea. The goal of this work is to forecast and to analyze sales at CS using ARIMA-Intervention model (IM) and exponential smoothing method (ESM), together with sales at supermarkets in South Korea. Considering that two retail trades above are homogeneous and comparable in size and purchasing items on off-line distribution channel, individual behavior and characteristic can be detected and also relative superiority of future growth can be forecasted. In particular, the rapid growth of sales at CS is regarded as an everlasting external event, or step intervention, so that IM with season variation can be examined. At the same time, Winters ESM can be investigated as an alternative to seasonal ARIMA-IM, on the assumption that the underlying series shows exponentially decreasing weights over time. In case of sales at supermarkets, the marked intervention could not be found over the underlying periods, so that only Winters ESM is considered. Research Design, Data, and Methodology - The dataset of this research is obtained from Korean Statistical Information Service (1/2010~7/2016) and Survey of Service Trend of Korea Statistics Administration. This work is exploited time series analyses such as IM, ESM and model-fitting statistics by using TSPLOT, TSMODEL, EXSMOOTH, ARIMA and MODELFIT procedures in SPSS 23.0. Results - By applying seasonal ARIMA-Intervention model to sales at CS, the steep and persisting increase can be expected over the next one year. On the other hand, we expect the rate of sales growth of supermarkets to be lagging and tied up constantly in the next 2016 year. Conclusions - Based on 2017 one-year sales forecasts for CS and supermarkets, we can yield the useful information for the development of CS and also for all retail trades. Future study is needed to analyze sales of popular items individually such as tobacco, banana milk, soju and so on and to get segmented results. Furthermore, we can expand sales forecasts to other retail trades such as department stores, hypermarkets, non-store retailing, so that comprehensive diagnostics can be delivered in the future.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.440-445
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• 1994

An application of H$_{\infty}$ synthesis to contact control of a manipulator is suggested. Based on computed torque linearization of a manipulator, a target dynamics for contact motion control is defined and used as a reference model. The target dynamics relates position and force errors through free motion impedance and force error compensators. The H$_{\infty}$ control synthesis is adopted to find an optimum the compensator for position tied force control in various directions of the end-effector. The optimization is performed on the augmented criteria, which trades off the sensitivity function of the errors and the input load at the joints. A design example of the compensator is provided that meets the design specifications.s.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.197-200
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• 2008

In most sensor networks, nodes can be easily compromised by adversaries due to hostile environments. Adversaries may use compromised nodes to inject false reports into the sensor networks. Such false report attacks will cause false alarms that can waste real-world response effort, and draining the finite amount of energy resource in the battery-powered network. A dynamic enroute scheme proposed by Yu and Guan can detect and drop such false reports during the forwarding phase. In this scheme, choosing a threshold value is very important, as it trades off between security power and energy consumption. In this paper, we propose a threshold determining method which uses the fuzzy rule-based system. The base station periodically determines a threshold value though the fuzzy rule-based system. The number of cluster nodes, the value of the key dissemination limit, and the remaining energy of nodes are used to determine the threshold value.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.177-180
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• 2008

There are many application areas of sensor networks, such as surveillance, hospital monitoring, and home network. These are dependent on the secure operation of networks, and will have serious outcome if the networks is injured. An adversary can inject false data into the network through the compromising node. Ye et al. proposed a statistical en-route filtering scheme (SEF) to detect such false data during forwarding process. In this scheme, it is important that the choice of the threshold value since it trades off security and overhead. This paper presents an adaptive threshold value determining method in the SEF using fuzzy logic. The fuzzy logic determines a security distance value by considering the situation of the network. The Sensor network is divided into several areas by the security distance value, it can each area to uses the different threshold value. The fuzzy based threshold value can reduce the energy consumption in transmitting.

• 재무관리연구
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• 제22권1호
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• pp.71-91
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• 2005

본 논문은 KOSPI 200 지수옵션 시장을 대상으로 각 월별 옵션 만기시 원월물에서 근월물로 바뀌는 옵션의 이월현상 효과를 분석하였다. KOSPI 200 지수옵션 시장은 외국의 제반 옵션 시장과는 달리 거래가 근월물에만 집중되고, 근월물에 대한 거래가 근월물의 만기일에도 매우 활발하게 이루어지는 특색을 갖고 있다. 따라서 원월물에서 근월물로 이전되는 과정에서 만기이월에 따라 옵션 가격이 영향을 받는다면, 이는 학술적으로는 옵션시장의 효율성에 대하여, 실무적으로는 옵션 거래전략에 대하여 함의를 갖는다고 말할 수 있다. 본 연구는 1999년부터 2001년까지의 KOSPI 200 지수옵션의 내재변동성을 활용하여 이루어줬으며 다음과 같은 결과를 얻었다. 첫째, 만기일을 포함한 주의 월요일부터 다음 월요일까지, 그리고 만기일 주간의 수요일에서 금요일까지 각 기간 동안의 콜옵션 가격은 전반적으로 하락하는 현상이 발생하였다. 둘째, 기간을 세분화하여 분석하였을 때, 콜옵션은 근월물의 만기일인 목요일에는 가격상승 현상이 나타났으나 해당옵션이 근월물이 된 금요일에는 더 큰 폭의 가격하락 현상이 나타났다. 반대로 풋 옵션은 목요일에는 가격하락 현상이, 금요일에는 가격상승 현상이 나타났다. 이러한 만기 이월현상은 처음으로 밝혀졌으며 그 방향성이 근월물의 만기일에는 옵션을 활용한 복제선물에의 매수포지션, 만기 익일에는 반대로 매도포지션으로 나타난 점은 KOSPI 200 지수 선물의 전반적인 저평가 현상에 대한 차익거래의 수단으로 투자자들이 옵션 시장을 활용한다는 개연성에 대한 증거가 된다. 이러한 결과는 옵션의 가격이 완전시장 가정 하에서 옵션의 가격에 영향을 미친다고 간주되는 변수들뿐만 아니라 옵션의 근월물 여부에도 영향 받고 있음을 의미하며, 이는 효율적 시장가설이나 완전시장 가설에 배치된다고 할 수 있다. 또한 위와 같은 결과를 바탕으로 투자전략을 수립할 때, 시장거래자중 콜옵션을 매수하려고 하는 투자자는 만기일 이후에, 반대로 콜옵션을 매도하려고 하는 투자자는 만기가 포함된 주 초반에 하는 것이 더 효과적임을 의미한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1259-1264
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• 1990

During the past two decades, a lot of researches have been done on the synthesis of grassroot heat exchanger networks(HEN). However, few have been dedicated to retrofit of existing heat exchanger networks, which usually use more amount of utilities (i.e. steam and/or cooling water) than the minimum requirements. This excess gives motivation of trades-off between energy saving and rearranging investment. In this paper, an algorithmic-evolutionary synthesis procedure for retrofitting heat exchanger networks is proposed. It consists of two stages. First, after the amount of maximum energy recovery(MER) is computed, a grass-root network featuring minimum number of units(MNU) is synthesized. In this stage, a systematic procedure of synthesizing MNU networks is presented. It is based upon the concept of pinch, from which networks are synthesized in a logical way by the heuristics verified by the pinch technology. In the second stage, since an initial feasible network is synthesized based on the pre-analysis result of MER and must-matches, an assignment problem between new and existing units is solved to minimize total required additional areas. After the existing units are assigned, the network can be improved by switching some units. For this purpose, an improvement problem is formulated and solved to utilize the areas of existing units as much as possible. An example is used to demonstrate the effectiveness of the proposed method.

• 산업경영시스템학회지
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• 제46권4호
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• pp.93-100
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• 2023

In this paper, an alternative inventory policy that trades off the bullwhip effect at an upstream facility with cost minimization at a current facility, with the goal of reducing system wide total expected inventory costs, when external demand distributjon is autocorrelated, is considered. The alternative inventory policy has a form that is somewhere between one that completely neglects the autocorrleation and one that actively utilizes the autocorrelation. For this purpose, a mathematical model that allows us to evaluate system wide total expected inventory costs for a periodic review system is developed. This model enables us to identify an optimal inventory policy at a current facility that minimizes system wide total expected inventory costs by the best tradeoff of the bullwhip effect at an upstream facility with cost minimization at a current facility. From numerical experiments, it has been found that (i) when the autocorrelation is negative, the optimal policy is one that actively utilizes the autocorrelation, (ii) when the autocorrelation is small and positive, the optimal policy is one that neglects the autocorrelation, and (iii) when the autocorrelation is large and positive, the optimal policy is somewhere between one that actively utilizes the autocorrelation and one that neglect the autocorrelation.

• 한국건설관리학회논문집
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• 제4권4호
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• pp.80-87
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• 2003

최근 건설업은 복합화$\cdot$고도화에 따라 효율적 인 관리가 요망되고 있다. 그 중 출역인원관리는 다양한 공정의 변화와 단위작업의 증가로 인하여 매우 중요하다. 이에 따라 IT기술의 발달과 더불어 공사관리의 효율화를 위하여 인터넷을 기반으로 웹(Web)을 통한 현장관리시스템을 사용하고 있다. 그러나 기존시스템은 작업 일보정보를 입력하는 협력사 중심이 아닌 시공사 중심으로 개발되었고, 협력사에서는 시스템을 사용할 수 있는 환경이 조성되지 못하고 있다. 또한 작업일보 정보가 보관 및 관리 될 때까지 몇 단계를 거 치 면서 정보의 손실 및 누락이 발생되어 작업 일보 정보의 신뢰성을 떨어트리고 있다. 따라서 본 논문은 작업 일보 정보를 수집, 보관, 관리할 수 있고 협력사 중심으로 효율적인 택트공정관리를 할 수 있는 시스템 제시를 목적으로 하였다.

• 한국환경복원기술학회지
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• 제21권2호
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• pp.39-51
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• 2018

Long-term unexecuted urban parks will be released from urban planning facilities after 2020, this may result in development of those parks. However, little research have been focused on how to develop those parks considering conservation, development, spatial pattern, and so on. Therefore, in this study, we suggested an optimization planning model that minimizes the fragmentation while maximizing the conservation and development profit using ACO (Ant Colony Optimization). Our study area is Suwon Yeongheung Park, which is long-term unexecuted urban parks and have actual plan for private development in 2019. Using our optimization planning model, we obtained four alternatives(A, B, C, D), all of which showed continuous land use patterns and satisfied the objectives related to conservation and development. Each alternative are optimized based on different weight combinations of conservation, development, and fragmentation, and we can also generated other alternatives immediately by adjusting the weights. This is possible because the planning process in our model is very fast and quantitative. Therefore, we expected our optimization planning model can support "spatial decision making" of various issue and sites.