• 경영과학
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• 제21권1호
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• pp.19-37
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• 2004

Since digital economy and electronic commerce are evolving rapidly. further shaping process of e-commerce over the Internet would be highly influenced by the impact of electronic commerce technologies. That is. the widespread application of electronic commerce technologies is remoulding classic business patterns and enabling organizations to deal with new ways of doing business with global suppliers. distributors, marketers and consumers. The objective of this study is to examine the scheme of electronic commerce technologies. analyzing the current state and what is expected of them In the future. However, it is difficult to clarify relationships with the every electronic commerce technology and to analyze the progress of each of them. This study focuses on the major electronic commerce application technologies relevant to e-business. In order to analyze the current state of electronic commerce technologies and relationships among them. this study has tried to gather experts' opinions using the Delphi method. For each major EC technology, this study has analyzed the current level. the technology scheme. the applicability, the economic influences of the EC technologies and the urgency of the technology development. This study will play a role of catalyser for the study of electronic commerce technologies and will provide guideline for future studies electronic commerce and information communication technology(ICT) diffusion.

• 한국경영과학회지
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• 제12권1호
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• pp.19-26
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• 1987

In analyzing time series, estimating the level or the current mean of the process plays an important role in understanding its structure and in being able to make forecasts. The studies the class of time series models where the level of the process is assumed to follow a random walk and the deviation from the level follow an ARMA process. The estimation and forecasting problem in a Bayesian framework and uses the Kalman filter to obtain forecasts based on estimates of level. In the analysis of time series, we usually make the assumption that the time series is generated by one model. However, in many situations the time series undergoes a structural change at one point in time. For example there may be a change in the distribution of random variables or in parameter values. Another example occurs when the level of the process changes abruptly at one period. In order to study such problems, the assumption that level follows a random walk process is relaxed to include a major level change at a particular point in time. The major level change is detected by examining the likelihood raio under a null hypothesis of no change and an alternative hypothesis of a major level change. The author proposes a method for estimation the size of the level change by adding one state variable to the state space model of the original Kalman filter. Detailed theoretical and numerical results are obtained for th first order autoregressive process wirth level changes.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1108-1113
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• 2017

In this paper, a bidirectional topology for quasi-Cuk dc/dc converter with capability of zero-voltage and zero-current-switching (ZVZCS) is proposed. The bidirectional quasi-Cuk (BQ-Cuk) converter has different voltage and current transfer ratio, reduced voltage stress on capacitor and capability of changing the output polarity in comparison with conventional bidirectional Cuk converter. In this paper, steady-state analysis of the quasi-Cuk converter with capability of ZVZCS in turn-on is presented. Then, critical inductances for transient from this operation to two new operations are calculated. Next, besides values designing of used elements, maximum and minimum value of their current and voltage are calculated. Finally, experimental results to verify the accuracy of the proposed converter in different operating modes are presented.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.815-818
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• 2003

New sensing and writing schemes for a magneto-resistive random access memory (MRAM) with a twin cell structure are proposed. In order to enhance the cell reliability, a scheme of the low voltage precharge is employed to keep the magneto resistance (MR) ratio constant. Moreover, a common gate amplifier is utilized to provide sufficient voltage signal to the bit line sense amplifiers under the small MR ratio structures. To enhance the writing reliability, a current mode technique with tri-state current drivers is adopted. During write operations, the bit and /bit lines are connected. And 'HIGH' or 'LOW' data is determined in terms of the current direction flowing through the MTJ cell. With the viewpoint of the improved reliability of the cell behavior and sensing margin, HSPICE simulations proved the validity of the proposed schemes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.932-934
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• 1998

In an electric substation, there are many sources of surge such as switching operations or lightning strokes. A grounding system submitted to such surge current presents very different behaviour from the observed under low frequency current. Especially, it has been reported that significant overvoltage occurs at the current feed-in point, and this may cause damages to other grounded components in the substation area. This paper describes the basic mechanism of improvement of grouding performance in transient state with auxiliary grounding grids.

• 한국국방경영분석학회지
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• 제24권2호
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• pp.146-161
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• 1998

This article develops model of the nonstationary state behavior of the multiechelon spare parts provisioning systems. This study is concerned with a problem of determining the near optimal requirements level of the spare parts, especially Concurrent Spare Parts(CSP). CSP is supplied with the procurement of new equipment system, and is used to sustain the equipment without resupply during the initial coverage period. We consider this situation as a multiechelon inventory model with several bases and one depot. And we assume an equipment system which consists of many types of parts would grounded if one of the parts fail. Also this multiechelon CSP problem is considering the nonstationary poisson failure process and nonstationary exponential repair process in a dynamic environment. We develop an efficient computational procedure to find the near optimal number of spare parts minimizing the total expected cost, while achieving the required system availability. Finally we present a simple example of suggested method.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.71-74
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• 2003

Today, s Businesses can only survive if they can sdapt fast, and this means their IT systems have to adapt too. A challenge for identifying and codifying reengineering expertise is to capture Both aspects of a successful enterprise business architecture(EBA) and suitable description language, with the contexts in which it works. In connected with the state of the art in the field of Web Services architecture and EBA, we propose to exploit the concept of business process execution language(BPEL), one among of description language. In addition, we review current a issue and problem of EAI and Workflow, and outline the main ingredients of a BPEL and EBA for building flexible Web Service. This paper is exploratory study in associated with enterprise architecture(EA) and description language.

• 한국경영과학회지
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• 제37권4호
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• pp.19-35
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• 2012

The Semantic Web technology, purporting to share, to reuse and to process by machines data stored in the Web environment, incessantly evolves to help human decision making; in particular, decision making based on data, or quantitative decision making. This trend drives researchers to fill the gap with strenuous efforts between the current state of the technology and the terminus of this evolution. The Semantic Web Constraint Language (SWCL) together with SWRL is one of these endeavors to achieve the goal. This paper focuses particularly on how to express the piecewise linear form in the context of SWCL. The importance of this ingredient can be fortified by the fact that any nonlinear expression can be approximated in the piecewise linear form. This paper will also provide the information of how it will work in the decision making process through an example of the Internet shopping mall problem.

• 한국국방경영분석학회지
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• 제23권2호
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• pp.25-44
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• 1997

Internet users been rapidly increased due to the convenient GUI environment. Current Web-based HTTP/CGI client/server architecture has several problems such as the CGI bottleneck, no maintaince of state, and no load balancing. However, with Java and CORBA technologies called“Object Web technology”, we can solve them because Java is not only a mobile code but also a platform-independent code, and CORBA has ability to build distributed object and language-independent object model. The goal of “Object Web technology”is to create multivendor, multiOS, multilanguage“legoware”using objects. This paper implement“Book Search System”which is Web-based client/server architecture using distributed objects. Environments of this implementation are Hangul Windows NT(included IIS) server, Hangul Windows 95 client, Visigenic's VisiBroker for Java 1.2 which is a product of CORBA 2.0, HTTP protocol on TCP-IP-based, Sybase SQL Anywhere 5.0 database server, and the interface between application server and database is JDBC-ODBC bridge middleware.

• 시큐리티연구
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• 제7호
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• pp.61-93
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• 2004

The terrorism threat against aviation industry is increasing after 9/11 incidents. As the way of preventing the future threat, this study is to review current status and make practical suggestions on Incheon International Airport security screening. The Library research method is utilized for this study. Chapter 1 is an introduction part and describes the general instruction. Chapter 2 describes the importance of aviation security and cases of aviation terrorism. Screening history is described in chapter 3 detailing operations and equipment. Status of IIAC(Incheon International Airport Corporation) security screening and prevention measures are described in chapter 4 and chapter 5 describes the final conclusion. In conclusion, if the introduction of state-of-the-art security equipment and modification of inadequate regulations come in first, whatever the threat exists, aviation terrorism can be prevented with the positive prevention efforts.