• 한국정보시스템학회지:정보시스템연구
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• 제3권
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• pp.133-145
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• 1994

Performance evaluation is essential for the successful management and operation of MIS. The more MIS grows and relevant investment enlarges, the more performance evaluation grows in importance. However, MIS managers as well as top management still have difficulty in evaluating the performance of MIS. This arises from various reasons, such as the specialty of MIS, diversified influences of MIS, multidimensionality of evaluation items, and the difference between evaluation levels. In this paper, MIS is understood in a broad sense. MIS's scope is of a very wide range from each application system to system innovation view. The MIS should support the firm's objectives, and, consequently, MIS evaluation should be implemented at corporate level, not merely at application system level. The most critical problem of MIS evaluation is that a systematic frame covering various viewpoints and factors of MIS evaluation does not exist. Not a single measure covers all aspects of MIS evaluation. To help resolve this problem, this paper proposes an hierarchical approach for practical use that includes most aspects of evaluation approaches from previous studies, and, furthermore, emphasizes the evaluation of strategic aspects of MIS.

• 한국통신학회논문지
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• 제35권7A호
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• pp.731-742
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• 2010

We propose an incremental relaying protocol in conjunction with opportunistic communication for differential modulation with an aim to make efficient use of the degrees of freedom of the channels by exploiting a imited feedback signal from the destination. In particular, whenever the direct link from the source to the destination is not favorable to decoding, the destination will request the help from the opportunistic relay (if any). The performance of the proposed system is derived in terms of average bit error probability and achievable spectral efficiency. The analytic results show that the system assisted by the opportunistic relaying can achieve full diversity at low SNR regime and exhibits a 30㏈ gain relative to direct transmission, assuming single-antenna terminals. We also determine the effect of power allocation on the bit error probability BEP) performance of our relaying scheme. We conclude with a discussion on the relationship between the given thresholds and channel resource savings. Monte-Carlo simulations are performed to verify the analysis.

• 한국통신학회논문지
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• 제33권7A호
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• pp.751-756
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• 2008

In this paper, we propose a modified I/Q diversity scheme receiver of UHF RFID reader system. The modified I/Q diversity receiver is more robust than the conventional homodyne receiver in the wireless noisy, fading channel and phase noise environments by making use of additional axes. In particular, it is shown that the closer the phase difference ${\theta}(t)$ between the reader and the tag to ${\pi}/4$, the larger performance improvement we can get. The performance of the proposed receiver is verified by equations and is demonstrated by the computer simulation for various difference ${\theta}(t)$ cases.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1266-1269
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• 2003

Many studies have indicated that most of a product's cost is fixed early in its lift cycle, before the original design cycle is complete. This implies that we should consider various aspects of product lift cycle at the design stage. This means the need of collaboration in design stage. Because the Internet provides instant access to a wealth of design information, the Internet is used by the collaborative design team members as a medium to share data, information and knowledge, and in some cases for product data management and project management by integrating the Web with appropriate technologies. This paper presents a real-time collaborative design system for powerful interaction performance, based on the Internet and Web technologies. Using The system use the client/server architecture and the purpose of the system is to provide a method that enables real-time view, review and modification of the 3D model through the Internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권6호
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• pp.1133-1146
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• 2011

Cognitive radio (CR) is considered one of the most promising next-generation communication systems; it has the ability to sense and make use of vacant channels that are unused by licensed users. Reliable detection of the licensed users' signals is an essential element for a CR network. Cooperative spectrum sensing (CSS) is able to offer better sensing performance as compared to individual sensing. The presence of malicious users who falsify sensing data can severely degrade the sensing performance of the CSS scheme. In this paper, we investigate a secure CSS scheme, based on the Kullback-Leibler Divergence (KL-divergence) theory, in order to identify malicious users and mitigate their harmful effect on the sensing performance of CSS in a CR network. The simulation results prove the effectiveness of the proposed scheme.

• 한국통신학회논문지
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• 제14권6호
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• pp.675-685
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• 1989

상호접송망은 병렬처리 시스템에서 매우 중요한 부분이다. 최근 다단상호 접속망에 대한 연구가 많이 행해지고 있다. 본 논문에서는 회선스위칭 다단상호접속망의 시뮬레이션 방법을 확장하여 분할된 ADM/IADM 접속망의 성능 평가를 하였다. 시뮬레이션 데이터에 의하여, 적용된 분할 방법에 의한 접속망 성능과 접속망에서 사용된 저지처리방식에 의한 접속망 성능 간의 관계를 보였다. 분석 결과, hold 방식을 사용하는 IADM 접속망이 RST 면에서 가장 나은 접속망 동작을 보이는 것으로 나타났다.

• 한국통신학회논문지
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• 제29권3A호
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• pp.257-265
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• 2004

MRC 다이버시티 수신 시스템에서 상호 독립적이고 동일한 전력을 갖는 동일 채널 간섭자들이 존재할 경우, Gray 부호화된 임의 직사각 QAM 신호의 성능을 분석하였다. 본 논문에서는 L개의 수신안테나를 갖는 MRC 수신 다이버시티 시스템에서 N명의 서로 독립적이고 동일한 나카가미 분포를 갖는 동일 채널 간섭자들의 신호가 수신되는 경우의 폐쇄형 (closed-form) 평균 비트 오류 확률 수식을 유도하였다. 이 수식은 수치 계산에 의해 쉽게 계산되는 초기하 함수를 이용하여 표현되었다.

• Journal of Information Technology Applications and Management
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• 제21권2호
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• pp.127-147
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• 2014

A methodology is often used in solving complex problems. As a typical case of complex problem solving, development of information systems mostly requires a use of system development methodology. However, it is not always easy or smooth for organizations to adopt the methodology and to achieve a positive outcome from their application in real project situations. Although there are a few studies to find out success factors in the implementation of the methodology, they did not take into consideration essential characteristics of the methodology. This study aims to analyze the quality of the methodology as a key determinant to influence the performance of the methodology application.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.589-590
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• 2016

Virtual Private Network (VPN) is commonly used in business situations to provide secure communication channels over public infrastructure such as Internet. This is important matters because these networks can be set-up with a lower cost of ownership compared to other means of securing communications. VPN is a proven technology that does provide security strong enough for business use. However, performance of these networks is also important in that lowering network and server resources can lower costs and improve user satisfaction. We analyzed network performance analysis of VPN protocols.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.108-110
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• 2018

모바일 IT 기기 환경에서 데이터베이스 엔진 사용이 보편화되고 있으며 모바일에 적합한 데이터베이스 엔진 개발과 발표가 뒤따르고 있다. 이 논문에서는 대표적이고 우수한 모바일 데이터베이스인 SQLite3를 선택하여 갱신 성능 및 특성을 테스트하기 위한 실험을 실시한다. 실험 결과를 평가하기 위하여 동일한 환경의 Oracle 데이터베이스의 결과와 비교한다.