• ETRI Journal
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• 제46권3호
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• pp.446-460
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• 2024

In this paper, we mathematically investigate a downlink non-orthogonal multiple access (NOMA) system for short-packet communications (SPC) in which the near users are used as full-duplex (FD) relays to forward intended signals from the source to a far user. In addition, partial relay selection is employed to enhance the performance of the FD relays under the impact of imperfect interference cancellation. At the far user, selection combining (SC) or maximal ratio combining (MRC) is employed to combine the signals received from the source and the selected FD relay. The analytical expressions for the average block error rate (BLER) of two users over flat Rayleigh fading channels are derived. Furthermore, closed-form asymptotic expressions of the average BLERs at the near and far users in high signal-to-noise ratio (SNR) regimes are obtained. The numerical results show that the analytical BLERs of the near user and far user closely match the simulation results.

• 디지털산업정보학회논문지
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• 제16권3호
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• pp.1-11
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• 2020

In this paper, we describe about the user terminal tagging-based embarkation/disembarkation management system and embarkation/disembarkation management method using this system. The system authenticates the validity of the user and on whether to board on the ship by tagging the user's terminal which the boarding reservation was made by using the management terminal provided in the ship. The system identifies on whether the user disembark in the ship by tagging the user's terminal. In the event of ship accident, it is easy to figure out the user and manage the non-contact boarding and disembarking. Therefore, we design the embarkation/disembarkation management system based on user's terminal tagging on the terminal provided in the ship and embarkation/disembarkation management method using this system. User terminal tagging can solve the problem of manpower required for the management of embarkation and disembarkation, the problem of requiring time to confirm the match between the reservation and the passenger, and the problem of increase of the possibility on the spread of infectious diseases due to face-to-face contact.

• 한국비블리아학회지
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• 제32권4호
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• pp.161-188
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• 2021

WHO에서 팬데믹을 선포하면서 다중이용시설인 도서관 역시 여러 변화를 맞이하고 있다. 전 세계적으로 각국의 국립도서관을 비롯한 대다수의 도서관이 휴관을 발표하였으며, 기존에 대면하여 제공하던 서비스를 대부분 비대면 서비스로 전환하였다. 하지만 그 서비스의 범위가 지자체 및 도서관별로 상이하여 사서의 소신있는 대응이 어렵고, 이용자 역시 불편을 겪고 있다. 따라서 본 연구에서는 도서관 비대면 서비스의 범위를 파악하고, 이에 대한 이용자의 인식조사를 통해 팬데믹 상황에서 도서관 비대면 서비스 운영 방향을 제안하고자 하였다. 이를 위해 37개의 공공도서관에 도서관 이용자를 대상으로 2020년 2월 12일부터 약 3주간 온라인 설문조사를 진행하였으며, 회수된 117부의 응답지를 SPSS 통계 프로그램을 활용하여 빈도분석, 회귀분석, 상관분석, 신뢰도 분석 등을 실시하였다. 설문결과 및 자료조사 결과를 통해 도서관 비대면 서비스 운영 방향으로 도서관 서비스 재정립, 도서관 비대면 서비스 확대, 이용자 교육 진행, 비대면 서비스에 대한 홍보 진행, 이용자 의견 수렴을 제안하였다.

• Communications for Statistical Applications and Methods
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• 제18권6호
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• pp.697-705
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• 2011

본 논문에서는 수리가 가능한 시스템에 대하여 무료 재생교체-비재생수리보증이 종료된 이후의 최적의 교체정책을 제안한다. 이를 위해서, 무료재생교체-비재생수리보증을 정의하고, 사용자 측면에서 무료재생교체-비재생수리보증이 종료된 이후의 보전모형을 고려한다. 최적의 보전정책을 결정하기 위한 기준으로는 사용자 측면의 단위시간당 기대비용을 사용하는데, 이러한 단위시간당 기대비용을 구하기 위해서 사용자측면의 기대순환길이와 총기대비용을 각각 유도한다. 끝으로 본 논문에서 제안된 무료 재생교체-비재생수리 보증이 종료된 이후의 최적의 교체정책을 설명하기 위해서 수치적 예를 살펴본다.

• 한국IT서비스학회지
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• 제11권1호
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• pp.15-37
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• 2012

This study is progressed for understanding of the acceptance intention differentiated through the view of smart phone non-user's adopting plan. And the research model is proposed in the view of new technology adopting, Innovation Diffusion Theory, Rogers 1995, and Technology Acceptance Model, Davis 1989. In the survey, SPSS 18.0 and AMOS 18.0 are used to analyze the 685 smart phone non-users data. The results of the feasibility analysis and the factor analysis show the measured variables determined in the statistical significant range. Also, 11 hypotheses, among the 16 hypotheses, are adopted by the hypothesis tests through the path analysis, one-way-ANOVA and hierarchial regression analysis. The results indicate variables affect on the non-smart phone user's adopting intention. The primary factor is the perceived usefulness, secondary factor is the social property, and the rest is the playfulness. And, the primary adoption factor is affected to early majority and late majority among each innovation adopters.

• Asia pacific journal of information systems
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• 제4권2호
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• pp.247-263
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• 1994

This paper reports the results of a field study investigating the effect of user participation and attitude on the success of information system implementation during the system development process. The theoretical framework for this research is based on the organizational change theory, in which the attitude affects the effects of user's participation. User participation and attitude were defined as independent variables and the performance of system implementation as dependent variable. User participation was defined as a direct participation by end users in the process of the new information system development. This was measured by user's participation/non-participation. User attitude refers to user's opinions or feelings before a new system is developed. This was measured by user's favor toward a system. The performance of system implementation was measured by the surrogate variable, the degree of individual satisfaction on developed system. To achieve the objective of this research, a field research method utilizing questionnaires were employed. They were distributed to 221 users present during and/or after system development. Among 185 questionnaires returned, 175 questionnaires were used for analysis. The major findings can be summarized as follows: First, there was no significant effect of user participation on user satisfaction. Second, there was a significant effect of user attitude on user satisfaction. Third, there was no significant interaction effect of user participation and attitude on user satisfaction. It is worth to note that the user's participation did not have any significant effect on the user's satisfaction. It seems the reason for the above result is due to user's involuntary participation. In fact, the user does not have much leverage in the process of system development, which may result in poor performance of user participation. Since user attitude is an important factor in the success of system implementation, however, a method to overcome unfavorable attitude of user should proceed all others.

• 대한간호학회지
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• 제29권5호
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• pp.1134-1146
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• 1999

The purpose of this study was to examine the correlation between Juvenile alcohol use and their criminal patterns. The data were collected through questionnaire surveys. Subjects serving for this study were 971 delinquent adolescents in Korea, sampled from 6 juvenile corrective institutions and 2 classification judging institutions, using a census method. Their age range was between 12 and 21. Data were analysed by IBM PC using SAS program. Statistical methods employed were Chi-square and frequency analysis. 1. Of 877 respondents, the number of adolescents committed criminal behaviors while the intoxicated were 230(26.2%), and 647(73.8%) were in a non-intoxicated state. 2. Adolescent under intoxication showed a higher rate of aggressive crimes and assault crimes, whereas adolescents under the non-influence of liquor tended to commit property climes and violations of criminal special law Drunken state adolescents during committing criminal behaviors used knifes, stones or fist-kicking as criminal tools, whereas drug use or without weapons in non drunken state. Most crimes have happened without any tools in both group. 3. In comparison of the alcohol user and the non-user, most alcohol-related crimes among adolescents were committed at AM 0:00 to AM 4:00 during the weekend in the dark, cloudy, and stormy-rainy day, while non-alcohol related crimes were at afternoon of weekday in the clear day. The places that the criminal activities occurred were streets, amusement places such as disco-theque, fields and their own house among alcohol users, whereas victim's house, another person's house and restaurant were chosen among non-alcohol users. 4. The victims assaulted by Juvenile offenders in both drunken and non-drunken state were mostly passer-by(65.4%), followed by their friends(25.1%). And the conditions of victims showed a significant differences between the drunken adolescents and the non-drunken adolescents. The victim's conditions assaulted by intoxicated delinquent adolescents were in quarreling or drunken state, whereas non-alcohol related crimes were directed against victims in a sleeping or irresistible state. 5. Almost over the half of delinquent adolescents perceived their delinquency as wrong behaviors. and alcohol non-user tended to more significantly perceive their criminal acts as wrong conducts. About the half of respondents answered that they committed their criminal acts in spite of having a very good Judgement while doing crimes, the author did not found a significant difference between the two groups. The reasons given for crimes were manifested as follows: it can be seen that ‘to get money for amusements’(30.4 % of all motives) were most common, followed by ‘to commit accidentally the offences’(23.8%), ‘curiosity or heroism’(18.9%). alcohol related crimes tended to be accidental and impulsively without any clear planning, while non-alcohol related crimes tended to be purposeful, directed to make money motivated by curiosity or a desire to live heroically. In Conclusions. the correlation between alcohol use and Juvenile criminal behaviors has been examined in this study. Generally, alcohol use had been found to be highly correlated with aggressive assault crimes including robbery, burglary and rape etc.

• Annals of Clinical Neurophysiology
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• 제5권1호
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• pp.16-20
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• 2003

Background: Mobile phone has become a very popular device used in everyday our lives. However, the possible hazard to human body such as brain tumor has been proposed intermittently. This unwanted possibility was calmed down due to the absence of definite evidence of hazard. This study was performed to see the effect of mobile phone use on the brain temperature. Methods: In 20 volunteers, we performed 4 steps of temperature measuring procedure. Four steps are pre-use (S1, basal state), wire-phone (S2, conventional telephone), PCS phone (S3, using 1,750~1,900 MHz), cellular phone (S4, using 820 MHz) states. Brain temperatures were measured by radiothermometer at 10 sites (5 sites in each hemisphere) of the brain after 5minutes of telecommunication through the phones. The final data were compared using paired t-test. Results: In PCS phone user group (Average; $35.73708^{\circ}C$), brain temperature decreased (with statistical significance, p<0.05), compared to those of non-user group (Average; $35.9527^{\circ}C$) or conventional wire phone user group. In cellular phone user group (Average; $35.82155^{\circ}C$), brain temperature decreased slightly (without statistical significance, p>0.05) compared to those of non-user group (Average; $35.9527^{\circ}C$) or conventional wire phone user group (Average; $35.922^{\circ}C$). The temperature change was not limited to the mobile phone applied side but on both hemisphere of the brain. Conclusion: In conclusion, mobile phone (especially PCS phone) decreased brain temperature in both hemispheres without side-to-side temperature difference. In addition, this study suggests possibility of radiothermometer application to the study of electromagnetic wave effect and protection method research in the future.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.37-42
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• 2021

NOMA (Non-orthogonal multiple Access) 시스템은 스펙트럼의 효율이 높아서 차세대 이동통신 방식으로 주목을 받고 있지만, 여러 사용자가 동시에 채널을 엑세스 하는 다중 사용자 시스템이므로 사용자 스케쥴링이 필요하다. 대표적인 스케쥴링 방식으로 PF (Proportional fairness) 스케쥴링 방식과 CDF (Cumulative distribution function) 스케쥴링 방식이 있는데, PF 스케쥴링 방식은 셀 가장자리에 위치한 사용자는 전송기회를 갖기가 매우 어렵다. 그러므로 최근에는 사용자들의 위치와 무관하게 동일한 전송기회를 갖는 CDF 스케쥴링이 주목을 받고 있다. 본 논문에서는 상향 NOMA 시스템에 CDF 스케쥴링을 적용하였을 때 사용자의 채널 획득확률, 사용자 수에 따른 오수신율, 그리고 송신 가중치에 따른 시스템의 오수신율을 시뮬레이션을 통하여 구하였다. 시뮬레이션 결과 각각의 사용자들의 채널 획득 확률이 동일함을 확인하였고, 사용자의 수가 증가할수록 오수신율은 감소하였다. 그리고 셀 가장 자리에 있는 사용자의 송신 가중치를 증가하여도 시스템의 오수신율에 미치는 영향은 미미함을 알 수 있었다.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권6호
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• pp.777-784
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• 2017

사용자의 행위는 건축물의 질을 규정하는 가중 중요한 기준중의 하나다. 일반적으로 건축공간에서의 사용자 행위에 대한 평가는 건물이 완성된 이후에 이루어 졌으며 최근 전산기술을 통한 사전 시뮬레이션에 대한 관심과 노력이 계속되고 있는 실정이다. 그러나 현존하는 사용자 시뮬레이션은 주로 대규모 공간의 단순한 탈출 등에 관한 것이 주를 이루고 있어 건축 공간상에서 벌어지는 다양한 사용자의 행태에 대한 시뮬레이션은 불가능한 상태이다. 본 연구는 보다 고도화된 사용자 시뮬레이션을 위한 사람형상의 지능형 에이전트의 개발은 위한 연구로서 온톨로지를 이용한 NPC의 지능화에 관한 연구이다. 연구의 주안점은 온톨로지를 통하여 구현된 공간정보와 사용자 정보를 추론하여 NPC(Non-player Character)가 가상공간 상에서 보다 지능적으로 자율주행 및 행동하게 하는 것이다. 본 연구에서는 온톨로지 추론을 기술을 가상공간에 접목시키는 방법에 대하여 주로 논의하고자 한다. 또한 이를 공간정보 상에서 온톨로지를 기반으로 기술된 정보와 이의 변화를 가시적으로 확인할 수 있는 온톨로지 가시화 기술을 제시한다.