• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4087-4102
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• 2014

Two-way relaying is an effective way of improving system spectral efficiency by making use of physical layer network coding. However, energy efficiency in OFDM-based bidirectional relaying with asymmetric traffic requirement has not been investigated. In this study, we focused on subcarrier transmission mode selection, bit loading, and power allocation in a multicarrier single amplified-and-forward relay system. In this scheme, each subcarrier can operate in two transmission modes: one-way relaying and two-way relaying. The problem is formulated as a mixed integer programming problem. We adopt a structural approximation optimization method that first decouples the original problem into two suboptimal problems with fixed subcarrier subsets and then finds the optimal subcarrier assignment subsets. Although the suboptimal problems are nonconvex, the results obtained for a single-tone system are used to transform them to convex problems. To find the optimal subcarrier assignment subsets, an iterative algorithm based on subcarrier ranking and matching is developed. Simulation results show that the proposed method can improve system performance compared with conventional methods. Some interesting insights are also obtained via simulation.

• 한국통신학회논문지
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• 제34권10C호
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• pp.946-954
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• 2009

일반적인 RFID 시스템에서는 리더와 백 엔드 데이터베이스 사이의 통신 채널을 안전한 채널로 가정하고 있다. 하지만 응용 환경에 따라 리더와 데이터베이스 사이의 통신 채널이 리더와 태그 간의 통신 채널처럼 안전하지 않은 채널을 통하여 메시지를 송수신 하게 되는 경우가 얼마든지 존재한다. 본 논문에서는 데이터베이스, 리더 그리고 태그 간의 모든 통신 채널이 안전하지 않은 공개 채널임을 가정하여 공개 채널 기반의 안전한 RFID 상호인증 프로토콜을 제안한다. 제안한 프로토콜은 공개된 채널 상에 송수신되는 모든 통신 메시지의 인증과 무결성을 보장하기 위해 안전한 일방향 해쉬 함수를 사용하였다. 또한 상호인증 후 데이터베이스와 태그가 다음 세션을 위해 기존의 비밀키를 새로운 비밀키로 각각 갱신하도록 하여 전방향 안전성을 제공하도록 설계하였다.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 1997년도 춘계학술대회논문집 지역정보단지 조성과정보기술의 활용
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• pp.271-285
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• 1997

This paper address the issues of satisfaction factors to measure the service quality in computer communication service users. In order to develope a satisfaction factors' model, we study appropriate quality factors of the service through the focus group interviews with service users, and surveys the quality levels that users have felt in services. It also analyzes the relationship between the user's quality level and the quality factors by the statistical analyses. Based on the optimal regression model, we suggest an appropriate satisfaction model in PC communication service areas. That model shows that most users are interested in the fare for use. Use-fare factor is the most powerful one to the satisfaction model. Second one is usefulness, next is correctness. But connect-status factor is the only negative one. Most users think that its factor is in the way of fluent communication. So to keep the competitiveness in the PC communication service, the sixth negative factor should be modified as soon as possible.

• 한국컴퓨터정보학회논문지
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• 제16권2호
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• pp.201-206
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• 2011

디지털 디스플레이어의 보급과 발달로 인하여 기존의 인쇄용 액자보다 디지털 액자에 대한 관심이 높아지고 있다. 우리는 이런 디지털 액자를 정적인 자료 디스플레이용도 뿐만 아니라 CCD 카메라와 조합하여 감시용 모니터링 장비로 활용하기 위한 새로운 LCD 전자 액자를 개발하였다. 개발된 액자는 감시용 화상 데이터의 보안을 위해 기존의 양방향 통신암호화를 대체하여 단방향 통신 암호화 방법으로 개발 하였다. 이 방법은 혼돈계의 단방향 동기화현상을 이용한 것으로 일정 시간 동안 동기화를 진행 시키면 어느 시점에서든 암호화와 복호화를 시킬 수 있는 방법으로 양방향 통신 암호화와 같은 결과를 얻을 수 있다. 또한, 우리가 제시한 이 방법을 유비쿼터스 기기의 근거리 통신방법에 적용한다면 보다 효율적인 결과를 얻을 수 있을 것으로 생각된다.

• 디지털융복합연구
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• 제16권11호
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• pp.433-440
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• 2018

본 연구 목적은 간호대학생의 자기효능감과 의사소통능력이 셀프리더십에 미치는 융복합적 영향을 확인하고자 시도하였다. 연구대상자는 일개 대학교의 재학생 320명을 대상으로 2018년 5월 2일 부터 5월 20일 까지 실시하였다. 자료분석방법은 SPSS 18,0을 이용하여 t-test, one-way ANOVA, pearson's correlation coefficient, stepwise multple regression으로 분석하였다. 연구결과는 일반적 특성에 따른 의사소통 능력은 학년, 셀프리더십은 나이, 학년에서 통계적으로 유의한 차이를 보였다. 자기효능감, 의사소통능력 및 셀프리더십간의 상관성은 셀프리더십과 의사소통능력(r=.376, p=000)은 통계적으로 유의한 정의 상관관계를 보였고, 대상자들의 의사소통능력이 셀프리더십을 14.1% 설명하는 것으로 나타났다. 이상의 결과로 간호대학생들의 대학생활 적응에 대한 다차원적인 이해를 돕고, 대학생활 적응을 위한 여러 가지 프로그램 개발과 방향 모색이 필요함을 제언한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3104-3110
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• 2011

This paper describes how to ensure safety of train by guaranteeing stable and continuous communication in RF-CBTC. CBTC System uses the wireless communication between onboard and wayside so that safety of wireless communication is the most important. Losing the position of train causes vital problem of train service. By losing the position of train, the other trains are blocked in the block and the train move by emergency mode so headway and safety cannot guaranteed. Therefore, safety is ensured by redundancy of wireless equipment. One of the ways to make redundancy is redundancy of equipment. However, the redundancy of equipment spends a lot of money to avoid interference in limited place like underground. Continuous communication is guaranteed by means of redundancy of wireless communication coverage to solve the problems even though one of the equipment is broken.

• 아동학회지
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• 제29권6호
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• pp.35-54
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• 2008

This study analyzed feelings of happiness in 550 5th grade children (273 males and 277 females) in elementary schools in Seoul and other regions. Measurement tools included personality (Eysenk, 1975), communication types (Barnes & Olsen, 1982), cognitive happiness (Waterman, 1993 and Ryff, 1989), affective happiness (Campbell et al. (1976), and eight open-ended questions about happiness developed by the author. Data analysis was by $X^2$, one-way ANOVA, stepwise regression analysis, and two-way ANOVA. Happiness of children was influenced by school grades, existence of supporters, economic level, number of siblings, and gender. Extroverted female children who had open communication with parents felt the highest degree of happiness.

• 한국보육지원학회지
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• 제15권6호
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• pp.207-226
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• 2019

Objective: The purpose of this study is to examine the relationship between caring thinking and communication skills of childcare center teachers, and the effect of caring thinking on communication skills. Methods: The subjects of this study were 152 teachers working at childcare centers in Gyeonggi-do, South Korea. The research tool used was a self-reporting questionnaire in order to examine caring thinking and the communication skills of those teachers. For the data analysis, one-way ANOVA, Pearson correlation analysis and multiple regression analysis were used. Results: First, there were significant differences in caring thinking and communication skills according to the age and academic background of the teachers. Second, there was a significant positive correlation between caring thinking and the communication skills of the teachers. Third, responsibility, respect, and a non-directive attitude among the sub-factors of the teachers had a significant impact on communication skills. Conclusion/Implications: In this study, it was found that caring thinking of the teachers was one of the variables that improved communication skills. These results suggest that there is a need to provide various programs and support for enhancing caring thinking as one of the ways to develop the communication skills of childcare center teachers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4967-4986
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• 2015

Multi-hop relaying communications have great potentials in improving transmission performance by deploying relay nodes. The benefit is critically dependent on the accuracy of the channel state information (CSI) of all the transmitting links. However, the CSI has to be estimated. In this paper, we investigate the channel estimation problem in one-way multi-hop MIMO amplify-and-forward (AF) relay system, where both the two-hop and three-hop communication link exist. Traditional point-to-point MIMO channel estimation methods will result in error propagation in estimating relay links, and separately tackling the channel estimation issue of each link will lose the gain as part of channel matrices involved in multiple communication links. In order to exploit all the available gains, we develop a novel channel estimation model by structuring different communication links using the PARAFAC and PARATUCK2 tensor analysis. Furthermore, a two-stage fitting algorithm is derived to estimate all the channel matrices involved in the communication process. In particular, essential uniqueness is further discussed. Simulation results demonstrate the advantage and effectiveness of the proposed channel estimator.

• 융합정보논문지
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• 제10권7호
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• pp.75-83
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• 2020

본 연구의 목적은 간호대학생의 의사소통 능력, 눈치가 대인관계조화에 미치는 영향을 파악하기 위함이다. 전라북도 소재의 B, H, H, J, K 대학에 재학 중인 3, 4학년 간호대학생 178명을 대상으로 자가보고식 설문조사로 시행되었다. 수집된 자료는 SPSS 21.0 프로그램을 이용하여 Independent t-test, One way ANOVA와 Pearson's correlation coefficient, Stepwise regression을 실시하였다. 연구 결과, 의사소통 능력이 가장 큰 영향력을 나타내는 변수였으며 눈치 파악, 간호학 전공에 대해 만족도 순으로 대인관계조화에 영향을 주는 것으로 나타났고 이들 전체변수의 간호대학생의 대인관계조화에 대한 설명력은 55%로 나타났다. 그러므로 의사소통 능력, 눈치 수준, 간호학 전공에 대한 만족도를 향상시키기 위한 전략이 간호대학생의 대인관계조화를 높이는 데 도움이 될 것이다.