• Journal of Communications and Networks
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• 제7권3호
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• pp.258-262
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• 2005

An adaptive beamforming system based on code filtering and differential correlation approaches is proposed. The differential correlation method was originally proposed for time delay estimation of direct sequence code division multiple access (DS-CDMA) systems under near-far ratio conditions and the code filtering correlation algorithm, on the other hand, was proposed for array response estimation in DS-CDMA systems under perfect power control. In this paper, by combining differential correlation concept with the code filtering beamforming technology, an accurate estimate of the beam forming weights and an enhanced performance of DS-CDMA systems under sever near-far ratio conditions is achieved. The system performance in terms of beam pattern and bit-error-rate (HER) shows that the proposed adaptive beamformer outperforms the conventional code filtering correlation technique.

• 기본간호학회지
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• 제6권3호
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• pp.397-413
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• 1999

The purpose of study is to prevent Nosocomial Respiratory Infection after understand the Correlation about Recognition and Performance of Critical Nurses. Data were collected from Critical Nurses 300 persons who has worked in 14 Subsidary Hospitals of University in Seoul and the collection periode is from Nov. 1st, 1997 to Jul. 14th. 1998. There are 40 questions and constructed by 6 Domains which Hand Washing, Suction Management, Airway Management, Respiratory Instrument. Ventilation and Respiratory Intervention. Also, the Data were analized with SPSS program. The obtained results are as follows : (1) The Mean of Recognition for Prevention of Nosocomial Respiratory Infection is 4.649 and by Domains, Respiratory Intervention(4.758), Suction Management (4.669), Airway Management(4.660), Hand Washing(4.651), Ventilation(4.605) and Respiratory Instrument(4.561) according to the Mean. (2) The Mean of Performance for Prevention of Nosocomial Respiratory Infection is 3.991 and by Domains, Respiratory Intervention(4.498), Airway Management (4.107), Hand Washing(4.084), Suction Management(3.898), Respiratory Instrument(3.860) and Ventilation(3.690) according to the Mean. (3) In the Correlation of Recognition and Performance for the Prevention of Nosocomial Respiratory Infection, Hand Washing(r=0.755, p=0.000), Airway Management(r=0.724, p=0.000), Respiratory Intervention(r=0.693, p=0.000) are mentioned significant correlation level. The Performance is good whenever the Recognition is high for Respiratory Instrument(r=0.143, p=0.054) but it's not significant level and Suction Management and Ventilation has no Correlation. (4) In Normal Properties, The Recognition is good(p<.05) when Nurses has plenty Clinical Career, Attendance of the Education and Exclusive Nurse for the Respiratory Infection is in Hospital. The Age is not significant correlation level statistically but represent a little correlation. The Performance is good(p<.05) when Elder Age, Attendance of the Education and the plenty Clinical Career is not significant correlation level statistically but represent a little correlation. Another properties has no menas. According to the results, Suggestion is as follows ; (1) Required Education to advance Recognition and Performance about Prevention of Nosocomial Respiratory Infection for a little clinical career of Nursing and younger Nurses. (2) It needs to analyze Performance about Prevention of Nosocomial Respiratory Infection by observation of research worker.

• 대한인간공학회지
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• 제27권2호
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• pp.39-47
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• 2008

This research was conducted to explore relationships among situation awareness, presence, and performance on a handheld game console. Situation Awareness was measured by SAGAT (Situation Awareness Global Assessment Technique) while presence was measured by PQ (Presence Questionnaire) version 3.0. The performance was measured by the number of aircraft shot down during the flight simulator game. The results show that both situation awareness and presence were positively significantly correlated with performance. In order to investigate the effect of performance level, subjects were divided into two significantly different groups: low and high performance groups. In the low performance group, both situation awareness and presence showed a significantly positive correlation with performance. The correlation between presence and situation awareness also showed a positively significant correlation. However, in the high performance group, there were no significant correlations among them. In conclusion, different performance levels could be said to be an important factor in the study of situation awareness and presence. Furthermore, this study also proved that the domain of research on situation awareness and presence was extended to small displays such as the handheld game console.

• 대한전자공학회논문지TC
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• 제45권7호
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• pp.32-37
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• 2008

DVB-S2 (Digital Video Broadcasting - Satellite Version 2)와 같은 위성 통신 시스템은 낮은 신호 대 잡음 비 (SNR; Signal-to-Noise Ratio) 및 큰 주파수 오차에서의 동작이 요구되므로 인해 초기 프레임 동기 과정에서 강건한 프레임 동기 획득을 위한 상관 방식이 필요하다. 초기 프레임 동기 획득을 위해서는 기존의 다양한 상관 방식이 존재하며 채널 환경에 따라 이들 상관 방식은 각각 다른 특성 및 성능을 갖는다. 본 논문에서는 낮은 신호 대 잡음 비 영역 및 큰 주파수 오차 존재 하에서도 우수한 성능을 보이는 상관기 구조를 제시하고 그 성능을 분석 및 검증한다. 제안하는 상관 방식은 동기 수열 내에서 확장된 동기 심볼 거리에 대한 차등 상관의 크기 합과 벡터 합을 각각 이용하며, 계산된 상관값과 수신신호의 Euclidean 거리를 활용하므로써 수신 신호와 동기 수열의 상관도를 극대화하는 효과를 갖는다. 크기 합 상관 방식의 경우 4 dB 이하의 신호 대잡음 비에서 주파수 오차의 존재 유무에 관계없이 최대 우도 (ML; Maximum likelihood) 방식의 근사화를 통해 유도된 방식을 포함한 기존의 알려진 모든 상관 방식보다 향상된 오율을 가지며, 벡터 합 상관 방식은 주파수 오차 감소함에 따라 크기 합 상관 방식보다도 더욱 우수한 성능을 가진다.

• 한국통신학회논문지
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• 제33권10C호
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• pp.836-843
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• 2008

본 논문에서는 공간 코릴레이션이 존재하는 레일리이 페이딩 환경에서 직교 STBC 알고리즘들의 성능을 이론적으로 유도하고 여러 가지 코릴레이션 조건에서 각 방식의 성능을 비교, 분석한다. 먼저, 채널 코릴레이션 행렬의 고유값 (eigenvalues)을 이용하여 M-ary PSK와 M-ary QAM 변조 방식에 대한 직교 STBC 알고리즘의 비트 에러율을 유도한 다음, $1{\sim}4bps/Hz$의 전송율에 대해 공간 코릴레이션에 의한 성능의 영향을 분석한다. 성능 분석 결과, 공간 코릴레이션이 0.9이상으로 비교적 큰 환경에서는 모든 전송율에 대해 Alamouti 방식이 Tarokh 방식 보다 우수한 성능을 제공함을 알 수 있었다.

• 한국통신학회논문지
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• 제40권7호
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• pp.1433-1440
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• 2015

본 논문에서는 이진 옵셋 반송파 (binary offset carrier: BOC) 신호의 추적 성능 향상을 위한 비모호 상관함수를 제안한다. 구체적으로는 BOC 신호의 부반송파를 여러 개의 펄스가 존재하는 형태로 해석하고, BOC 신호의 자기상관함수를 여러 개의 부분상관함수들의 합으로 해석한다. 이후 두 개의 부분상관함수를 조합하여 새로운 두개의 부상관함수를 생성하고, 부상관함수와 부분상관함수의 조합을 통하여 폭을 조절할 수 있으며 주변 첨두를 가지지 않는 비모호 상관함수를 제안한다. 모의실험을 통해 신호 추적에 제안한 상관함수를 이용한 경우 기존의 상관함수들을 이용한 경우에 비해 더욱 향상된 추적 오류 표준편차를 가지는 것을 확인한다.

• Journal of the Korean Data and Information Science Society
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• 제21권6호
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• pp.1071-1079
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• 2010

10종경기 전 종목에 관한 효율적이고 포괄적인 동시훈련은 불가능하다는 Tidow (2000)의 지적처럼 힘, 민첩성, 속력, 지구력 및 개개인의 심리적 특성을 요구하는 10종경기에서 선수들이 가지고 있는 체력과 기술을 각 종목에 효율적으로 안배하여 활용할 수 있는 능력은 매우 중요하다. 본 연구에서는 1990년 이후 거행된 올림픽과 세계육상선수권대회에서의 10종경기 기록을 이용하여 세계적인 선수들은 경기운영을 어떻게 하는지 선도표, 대응분석, 정준상관분석 및 상관분석을 이용하여 살펴보았다. 그 결과 최상위권에 속하는 선수들은 스피드가 매우 뛰어나며 투척경기에도 강하나 지구력 경기에만 약점을 보였으며 경기력 패턴이 뚜렷하게 나타났다. 또한 상위권 선수들은 도약경기에 강세를 보이고 최하위권 선수들은 지구력 경기에 강점을 보였다.

• 한국통신학회논문지
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• 제36권4A호
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• pp.312-317
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• 2011

본 논문에서는 주파수도약 무선 통신 시스템의 초기동기 구조를 모델링하고 시뮬레이션을 통해 주파수도약 성능을 알아보았다. 주파수도약 동기성능은 실제 시스템에서 측정이 어렵기 때문에 본 연구에서는 주파수도약 초기동기 구조를 실제 시스템과 유사하게 모델링하고, AWGN 채널 환경에서 최적 상판동기 임계값과 동기성능을 시뮬레이션 하였다. 그 결과 낮은 SNR에서도 주파수도약 시스템의 상관동기 최적 임계값 및 동기획득을 확인하였다.

• 디지털융복합연구
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• 제7권4호
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• pp.141-148
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• 2009

The purpose of this study is to examine the causal correlation between communication skill of organization and their job performance. In our model, we used these variables - innovation awareness, job satisfaction, organizational commitment as a parameter. In order to verify the hypothesis based on research model, a survey among researchers (sample size=117) who work in food company was carried out. Analyzing hypothesized model and following the statistical procedure, we could assure that there exist positive correlation with communication skill, innovation awareness, job satisfaction, organizational commitment and organizational performance. A coefficient of correlation between those variables was clearly high in the group with good communication skill. Among the parameters, the variable of innovation awareness was more effected on their job performance.

• 수산해양교육연구
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• 제25권1호
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• pp.29-39
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• 2013

The purpose of this study is to analyze middle school teachers' concern about and implementation degree of performance assessment in China. The research questions are as follows: First, what kind of concern is held by middle school teachers who implement performance assessment? Second, is there any significant difference in stages of concern the teachers on performance assessment according to their gender, education level and teaching career? Third, which level of use is shown by middle school teachers who implement performance assessment? Fourth, what is the correlation between middle school teachers' Stages of Concern and Levels of Use on performance assessment? This study was conducted based on a Concerns-Based Adoption Model (Hall, 1973; CBAM) that viewed teachers as the most primary factor of the execution of innovation, in this case, performance assessment. Performance assessment is assessment based on observation and judgement (Stiggins, 1994), and require test takers to complete a process or produce a product in a context that closely resembles real-life situations. The subjects of this study were randomly sampled from 120 middle school teachers throughout Bei-Jing, China. The questionnaires were distributed to them by mail, and they were asked to return their questionnaire by mail. The collect data were analyzed by SPSS/WIN 18.0 program in terms of frequency, correlation, or MANOVA. Frequency analysis was used to analyze concern of middle school teachers on performance assessment. To gain an frequency of the individuals in each stage, we regarded the stage in which a teacher had his/her highest score as his/her relevant stage. Correlation analysis was adopted to identify the correlation between teachers' stage of concern and level of use. To analyze the difference of the concern of China middle school teachers on performance assessment according to their individual background variables such as gender, education level, and teaching career, MANOVA was performed.