• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.259-261
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• 2000

UPFC(Unified Power Flow Controller) consists of two voltage sourced converter(VSC)s inserted into AC system through series and parallel coupling transformer, where two VSCs are linked by capacitor at DC-side. Since VSC acts as an AC voltage source behind a reactance, where both magnitude and phase angle of the source are controllable, UPFC can be represented by the equation related to input-output relation of two VSCs. Voltage control of DC-link capacitor provides the path of real power flow between two VSCs. While UPFC is controlled for maintaining the given reference value in steady state, it should be controlled for damping power oscillation in dynamics. For such a control objective, the control strategy based on the energy function was proposed and has been shown to be effect and robust for damping power oscillation of power system. In this paper, UPFC model based on the VSC was analysed and applied to power-flow control and stability analysis. The control strategy based on the energy function is adopted for damping power oscillation of power system. The effectiveness of proposed control strategy was verified by simulation study

• 한국컴퓨터정보학회논문지
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• 제17권4호
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• pp.155-161
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• 2012

본 연구의 목적은 제조기업이 자원기반관점의 생산전략을 추구하면서 경쟁력의 원천이 되는 핵심역량을 육성하고, 가치혁신전략의 일환으로서 혁신 제품개발 및 사업 모델 혁신을 추진하여 경영을 다각화할 때, 기업성과에 미치는 구조적 영향 관계를 분석하고, 또한 핵심역량의 육성이 가치혁신전략의 수행에 어떤 영향을 미칠 것인지를 검증하는 데 있다. 결과적으로 본 연구를 통하여 제조기업에 대한 핵심역량과 가치혁신전략 그리고 기업성과 간에 논리적, 개념적으로 타당한 구조적 관계가 있음이 확인되었다. 또한 기업이 궁극적인 목적인 기업성과를 극대화하기 위해서는 미래 경쟁력의 원천이 될 핵심역량을 전략적으로 육성하고, 가치혁신전략을 기반으로 경영을 다각화해야 함을 알 수 있다.

• 통상정보연구
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• 제9권2호
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• pp.65-86
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• 2007

This paper reviews the properties and application methods of widely used types of risk measures, identifies the rationale and business-side effects of hedging, derives the theoretical formula of optimal hedging ratio, and analyzes the various functional aspects of VaR(Value-at-risk) as a risk measure and a hedging tool. Especially this paper focuses on the characteristics of VaR compared with other risk measures in terms of their own principal determinants and identifies its stronger aspects in the dimension of hedging strategy tools. As well, this paper provides the detailed processes deriving the optimal hedge ratios based on the distributional parameters and risk factors. In addition, this paper presents the detailed and substantial processes of estimating the minimum variance hedge ratio and minimum-VaR hedge ratio using the actual data and shows that the minimum variance hedge ratio proves helpful for many cases although it is not appropriate for the non-linear portfolio including the option contracts. We demonstrate the trade-off relationship between the minimum variance hedge strategy and the minimum-VaR hedge strategy in their hedging costs and performances through calculation of the respective VaRs and variances of unhedged and hedged portfolios and the optimal hedge ratio and hedging effectiveness values for the given long position in US Dollar with the short position in Euro.

• 한국안광학회지
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• 제20권4호
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• pp.405-414
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• 2015

목적: 안경원 고객에 대한 군집분석을 통하여 고객의 세분시장 특성을 분석하고, 이를 안경원 마케팅 전략에 유용한 지표로 삼을 수 있도록 하고자 한다. 방법: 2015년 3월 10일부터 3월 31일 사이에 서울 및 경기북부지역의 안경원을 방문한 고객을 대상으로 설문조사를 실시하였으며, SPSS v.10.0 통계 패키지 프로그램을 활용하여 분석하였다. 분석방법은 빈도분석, 가치관 변수에 대한 요인분석, 시장세분화를 위한 군집분석, 교차분석을 실시하였다. 결과: 가치관에 근거하여 시장을 세분화하였다. 마케팅 전략을 수립할 때 "중도가치 지향 집단", "고도가치 지향 집단", "고도가치 지향 비종교 집단"의 3가지 군집으로 고객을 분류하여 전략을 수립하는 것이 좋은 것으로 나타났다. 누진굴절력렌즈의 마케팅 전략은 "중도가치 지향 집단"에서 자영업자를 중심으로 하는 전략이 가장 중요한 것으로 나타났다. 결론: 군집분석을 통하여 시장을 세분화한 결과 3가지 군집으로 분류되었으며, 누진굴절력렌즈의 가장 중요한 고객은 "중도가치 지향 집단"에서 41세 이상의 자영업자임을 알 수 있었다.

• 한국경영과학회지
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• 제39권3호
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• pp.63-82
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• 2014

The main objective of this research is to investigate whether the RFM (recency-frequency-monetary value) information of a customer's redemption behavior of loyalty points can improve the prediction of future value of the customer. The conventional measurement of customer value has been primarily based on purchase transactions behavior although a customer's future behavior can be also influenced by other interactions between the customer and the firm such as redemption of rewards in a loyalty program. We theorize why a customer's redemption behavior can influence her future purchases and thereby the customer's total value based on operant learning theory, goal gradient hypothesis, and lock-in effect. Using a dataset from a major book store in Korea spanning three years between 2008 and 2010, we analyze both purchase transactions and redemption records of over 10,000 customers. The results show that the redemption-based RFM information does improve the prediction accuracy of the customer's future purchases. Based on this result, we also propose an improved estimate of customer lifetime value (CLV) by combining purchase transactions and loyalty points redemption data. Managerial implications will be also discussed for firms managing loyalty programs to maximize the total value customers.

• 산업공학
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• 제23권4호
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• pp.300-310
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• 2010

This paper is about an optimal investment portfolio strategy. Financial data of stocks, bonds, and savings from January 2. 2001 through October 30. 2009 were utilized in order to suggest the optimal portfolio strategies. Fundamental analysis and technical analysis were used in stocks-related strategy, whereas passive investment strategy and active investment strategy were used in bond-related strategy. The score is assigned to each stock index according to the suggested strategies and set trading rules are based on the scores. The simulation has been executed about each 29,400-portfolios and we figured out with the simulation result that 26.75% of 7,864 portfolios are more profitable than average stock market profit (22.6%, Annualized). The outcome of this research is summarized in two parts. First, it's the rebalancing strategy of portfolio. The result shows that value-oriented investment(long-term investment) strategy yields much higher than short-term investment strategies of stocks or active investment of bonds. Second, it's about the rebalancing cycle forming the portfolios. The result shows that the rate of return for the portfolio is the best when rebalancing cycle is 12 or 18 months.

• 한국전자거래학회지
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• 제22권1호
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• pp.123-146
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• 2017

소비자들이 SNS에 공유하는 정보는 소비자들의 구매나 선택에 대한 결정에 많은 영향을 미친다. 이에 소셜 빅데이터를 활용하여 소비자 가치를 분석한 새로운 연구방법론에 주목할 필요가 있다. 이러한 맥락에서 본 연구의 목적은 소셜 빅데이터 분석을 통해 소비자의 가치 인식을 계량적으로 분석해 보고자한다. 이러한 분석 결과를 토대로 광고전략 개발에 적용할 수 있는지를 규명하고자 하였다. 본 연구에서는 3가지 스마트폰 브랜드에 대해 텍스트 마이닝과 긍 부정 이미지 분석을 활용함으로써 소비자 가치 구조를 파악하였다. 분석결과 브랜드별 소비자의 가치 인식에 대한 감성적인 측면과 이성적인 측면에서 차별적인 내용을 선별할 수 있었다. 갤럭시 S7과 아이폰 6S의 경우 출시일 이전에는 감성적인 측면이 중요한 것으로 나타났지만 출시일 이후에는 이성적인 측면이 중요한 것으로 나타났다. 그러나 LG G5의 경우 출시일 이전이나 이후 모두 감성적인 측면이 중요한 것으로 나타났다. 또한 소비자 가치 인식의 분석 결과를 바탕으로 핵심적인 광고전략 2가지 안을 제안할 수 있다. 갤럭시 S7의 경우 광고전략 개발 시 제품속성에 대한 성능이나 차별화된 기능 등 이성적 측면을 강조해야 할 필요성이 있다. LG G5의 경우 광고전략에서 제품을 사용함으로써 느껴지는 행복감, 설레임, 즐거움, 재미 등의 감성적 측면을 광고전략 개발에 중요하게 고려할 필요가 있다. 결과적으로 본 연구는 소비자 가치 분석을 통해 실제 광고전략에 좋은 기준을 제시할 것으로 판단된다. 광고전략은 주로 직감이나 경험에 의해 이루어진다. 이에 소셜 빅데이터 분석을 통한 소비자의 가치 인식 분석으로 광고전략을 개발하는 것은 중요한 시사점을 안겨 줄 것으로 판단한다.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 2010년도 춘계국제학술대회
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• pp.203-212
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• 2010

The mam purpose of this study is to find out how perceived risk elements influence to customers' perceived value and repurchase intention in the electronic commerce environment. To achieve the goal, we set 6 sub-dimensions - privacy risk, social risk, time loss risk, economic risk, psychological risk, and performance risk - based on comprehensive consideration of related studies, and established a research model included 2 factors such as perceived value and repurchase intention to measure performance in internet shopping malls. From 174 customers of the electronic commerce shopping malls survey data have been collected and analyzed based on the covariance structural model method. The results of this study are summarized as follows. Firstly, five perceived risk characteristics of privacy risk, time loss risk, economic risk, psychological risk, and performance risk are significantly positive effect on perceived value. Secondly, perceived value IS very significantly related to repurchase intention in electronic commerce shopping malls. Consequently, we discussed the strategies to create perceived value and repurchase intention in electronic commerce environment. Also we suggested the implications and further research directions.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1163-1168
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• 2006

Manufacturing technology for the production of high value-added fine chemical products is emphasized and getting more attention as the diversified interests of customers and the demand of high quality products are getting bigger and bigger everyday. Thus, the development of advanced batch processes, which is the preferred and most appropriate way of producing these types of products, and the related technologies are becoming more important. Therefore, high-precision batch distillation is one of the important elements in the successful manufacturing of fine chemicals, and the importance of the process operation strategy with quality assurance cannot be overemphasized. Accordingly, proposing a process structure explanation and operation strategy of such processes including batch processes and batch distillation would be of great value. We investigate optimal operation strategy and production planning of multi-purpose plants consisting of batch processes and batch distillation for the manufacturing of fine chemical products. For the short-term scheduling of a sequential multi-purpose batch plant consisting of batch distillation under MPC and UIS policy, we proposed a MILP model based on a priori time slot allocation. Also, we consider that the waste product of being produced on batch distillation is recycled to the batch distillation unit for the saving of raw materials. The developed methodology will be especially useful for the design and optimal operations of multi-purpose and multiproduct plants that is suitable for fine chemical production.

• Journal of Power Electronics
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• 제19권6호
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• pp.1554-1565
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• 2019

When grid voltage is unbalanced, the grid-connected output current and power of Virtual Synchronous Generators (VSGs) are distorted and quadratic. In order to improve the power quality of a grid connected to a VSG when the grid voltage is unbalanced, a comprehensive coordinated control strategy is proposed. The strategy uses the positive sequence current reference command obtained by a VSG in the balanced current control mode to establish a unified negative sequence current reference command analytical expression for the three objectives of current balance, active power constant and reactive power constant. In addition, based on the relative value of each target's volatility, a comprehensive wave function expression is established. By deriving the comprehensive wave function, the corresponding negative sequence current reference value is obtained. Therefore, the VSG can achieve the minimum comprehensive fluctuation under the premise that the three targets meet the requirements of grid connection, and the output power quality is improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.