• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.48-54
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• 2021

In most existing researches on non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC), uniform sources have been usually considered. For the first part in this two-part paper, for the strongest channel gain user, we showed that the bit-error rate (BER) for the optimal maximum a-posteriori (MAP) receiver for the non-uniform source improves slightly, compared to that of the conventional receiver for the uniform sources. We demonstrate that in communication scenarios of the non-uniform source NOMA schemes, for the weakest channel gain user, the BER performance of the optimal MAP receiver for a non-uniform source improves greatly, compared to that of the conventional receiver for uniform sources. We first derive an analytical expression of the BER for non-uniform source NOMA with SSC. Then, simulations demonstrate that the BER of the optimal MAP receiver for the non-uniform source improves, compared with that of the conventional maximum likelihood (ML) receiver for the uniform sources. In result, the proposed optimal MAP receiver for the non-uniform source could be a promising scheme for SSC NOMA, with improved BER performances.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.179-184
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• 2012

기존의 무선 RF 통신은 근거리에서 전력손실이 상대적으로 크고, 전파간섭 및 방해, 재밍 등에 민감하다. 이러한 단점을 보완하는 대안으로 자외선을 이용한 통신 방식에 대한 연구가 최근 관심을 받고 있다. 본 논문에서 자외선을 이용한 비가시거리 통신의 data rate 특성에 대해 시뮬레이션한 결과를 제시하였다. On-off keying 방식을 사용하는 비가시거리 자외선 통신에서 data rate는 송신 빔의 방향, 수신빔의 빔 폭, 송신 전력에 의해 큰 영향을 받는다는 것을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.231-234
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• 2008

본 논문에서는 음향의 비선형 채널에 적합한 새로운 수중 무선 동신 시스템을 제안하였다. 일반적으로 음향의 비선형 채널에서의 통신은 두 음파의 차의 주파수를 가지는 음파에 대한 파라메트릭 효과를 이용한 통신을 한다. 이러한 동신기법에서는 위상변조를 이용한 통신의 구현은 쉽지 않았다. 본 논문에서 제안된 시스템에서는 위상변조 후 오프셋을 주어 통신하는 비선형 채널에 적합한 통신 방식을 제안하였고 시뮬레이션을 통하여 그 타당성을 입증하였다.

• 한국정보전자통신기술학회논문지
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• 제7권2호
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• pp.86-91
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• 2014

논문에서는 레이더 시스템에서 코히런트 집적과 비 코히런트 집적의 SNR 성능에 대해서 비교한다. 본 논문에서는 레이더 시스템에서 반사파와 전송파의 왜곡을 방지하기 위해 펄스파를 송신 파형으로 사용하였다. 본 논문에서는 포락선 검파기 앞에서 처리하는 코히런트 집적과 포락선 검파기 뒤에서 처리하는 비 코히런트 집적을 사용하여 목표물 탐지 거리를 추정하고 집적 방식에 따른 SNR 성능을 비교한다. 모의실험을 통해서 코히런트 집적과 비 코히런트 집적의 SNR 성능을 비교 분석하였다. 코히런트 집적이 비 코히런트 집적보다 SNR 성능이 우수함을 입증하였다.

• 한국콘텐츠학회논문지
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• 제20권10호
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• pp.259-267
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• 2020

수업은 교수자와 학습자 간의 커뮤니케이션을 기반으로 이루어진다. 수업에서 교수자의 언어적 커뮤니케이션과 더불어 비언어적 커뮤니케이션은 중요한 역할을 담당하고 있으며 학습과정과 학습성과에 영향을 준다는 점에 관심이 점차 증가하고 있다. 본 연구는 문헌연구를 근거하여 교수자의 비언어적 커뮤니케이션과 연계된 학습자의 학습과정 변인으로 감성적 실재감과 라포, 학습성과 변인으로 학습만족도를 정하였다. 본 연구의 목적은 대학 수업에서 교수자의 비언어적 커뮤니케이션과 대학생의 감성적 실재감, 라포 및 학습만족도 간의 관계를 구조적으로 규명하는 데 있다. 경기지역 A대학교 및 대전지역 K대학교의 재학생 378명으로부터 자료를 수집하였으며 구조방정식을 통해 자료를 분석하였다. 연구결과, 교수자의 비언어적 커뮤니케이션은 대학생의 감성적 실재감과 라포에 정적 영향을 미쳤다. 감성적 실재감은 라포와 학습만족도에 정적 영향을 미쳤으며 라포는 학습만족도에 정적 영향을 미쳤다. 교수자는 수업 중 비언어적 커뮤니케이션의 역할을 인식하고 적절하게 활용할 수 있어야 할 것이다. 본 연구결과는 대학 수업에서 교수자의 비언어적 커뮤니케이션 활용에 대한 기초자료로 활용될 수 있을 것이다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권2호
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• pp.43-51
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• 2021

As the number of mobile devices has been increasing tremendously, system capacity should be enlarged in future next generation communication, such as the fifth-generation (5G) and beyond 5G (B5G) mobile networks. For such future networks, non-orthogonal multiple access (NOMA) has been considered as promising multiple access technology. In this paper, to reduce both latency and complexity in existing NOMA, we propose non-successive interference cancellation (SIC) NOMA with asymmetric binary pulse amplitude modulation (2PAM), nearly without bit-error rate (BER) loss. First, we derive the closed form of BER expressions for non-SIC NOMA with asymmetric 2PAM, especially under Rayleigh fading channels. Then, it is shown that the BER performance of the stronger channel user who is supposed to perform SIC in conventional NOMA can be nearly achieved by the proposed non-SIC NOMA with asymmetric 2PAM, especially without SIC. Furthermore, we also show that the BER performance of the weaker channel user in conventional NOMA can be more closely achieved by the proposed non-SIC NOMA with asymmetric 2PAM. These BERs are shown to be achieved over the part of the power allocation range, which is consistent with the NOMA principle of user fairness. As a result, the non-SIC NOMA scheme with asymmetric 2PAM could be considered as a promising NOMA scheme toward next generation communication.

• 대한가정학회지
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• 제40권9호
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• pp.127-141
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• 2002

This research aims to examine the influence of facilitative communication between mother and high school daughter on daughter's perceived family cohesion, family adaptability, and satisfaction of mother's working or non-working status. In order to verify statistically the research questions above, experimental tools were made for each variable, and Cluster Sampling with Stratification was conducted among high school girls in Seoul. A total of 670 questionnaire sheets were administered to 13 high schools for girls in December 2001, and only 501 sheets were used for data analysis. The SPSS 10.0 package was used for factor analysis, reliability analysis, multiple regression analysis. The following results were obtained: 1) Mother-high school daughter's facilitative communication significantly influences daughter's perceived family cohesion. In general, mother-high school daughter's facilitative communication had R square of 27.6% with regards to daughter's perceived family cohesion. 2) Mother-high school daughter's facilitative communication significantly influences daughter's perceived family adaptability. In general, mother-high school daughter's facilitative communication had R square of 25.3% with regards to daughter's perceived family adaptability. 3) Mother-high school daughter's facilitative communication significantly influences daughter's perceived satisfaction of mother's working of non-working status. In general, mother-high school daughter's facilitative communication had R square of 24.0% with regards to daughter's perceived satisfaction of mother's working status, and 7.4% with regards to non-working status.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2838-2858
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• 2019

Traditional channel models for vehicle-to-vehicle (V2V) communication usually assume fixed velocity in static scattering environment. In the realistic scenarios, however, time-variant velocity for V2V results in non-stationary statistical properties of wireless channels. Dynamic scatterers with random velocities and directions have been always utilized to depict the non-stationary statistical properties of the channel. In this paper, a non-stationary geometry-based cooperative scattering channel model is proposed for multiple-input multiple-output (MIMO) V2V communication systems, where a birth-death process is used to capture the appearance and disappearance dynamic properties of moving scatterers that reflect the time-variant time correlation and Doppler spectrum characteristics. Moreover, our model has more straight and concise to study the impact of the vehicular traffic density on channel characteristics and thus avoid complicated procedure in deriving the analytical expressions of the channel parameters and functions. The numerical results validate our analysis and demonstrate that setting important parameters of our model can appropriately build up more purposeful measurement campaigns in the future.

• 보건행정학회지
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• 제25권4호
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• pp.333-342
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• 2015

Background: The purposes of this study is to analysis the differences of the job satisfaction between regular and non-regular workers in hospitals. Methods: The samples used for data analysis are 632 workers of 6 hospitals using a standardized questionnaires in B, C, D, and G provinces. In research methodology, all the data were analyzed with descriptive statistics, t-test, Pearson's correlation, and multiple linear regression analysis. Results: In case of regular workers, communication, working conditions and employee benefit, and education were found to have a significant positive (+) effect on job satisfaction. In case of non-regular workers, empowerment, reward systems, communication, working conditions, and employee benefit had a significant positive (+) effect on job satisfaction. Conclusion: These results showed that hospitals needed to reinforce communication, working conditions and employee benefit to regular and non-regular workers in order to improve job satisfaction. Especially, more empowerment, working conditions, and employee benefit should be given to non-regular workers.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.233-235
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• 2005

Non-contact power supply (NCPS), as a clean and safe energy supply concept has been applying wildly. Comparing with the conventional transformer the non-contact transformer has a large air gap between the long primary winding and the secondary winding. Due to it, the non-contact transformer has increased leakage inductance and reduced magnetizing inductance. So the high frequency series resonant converter has been widly used on the non-contact power supply system for transferring the primary power to the secondary one, from what a high influence voltage can be gained on the secondry coil even though the large air gap exists. However, it still has the disadvantages of the load sensitive voltage gain characteristics when load is changing. In this paper, we propose a fuzzy logic controller to adjust the frequency of the inverter to track the resonat which is changing when the load is change.