• International journal of advanced smart convergence
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• 제3권1호
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• pp.1-6
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• 2014

An expert network administrator is not always stationed as disasters happen. In that case, it is desirable that a novice administrator is capable of taking part in network recovery operations as well. In this paper, aknowledge-based network management system in emergency situations is presented. We use the Active Information Resource based Network Management System (AIR-NMS) to relieve the human administrator from parts of her management tasks and present an interface that remotely can control this management system. The effectiveness of the system is demonstrated by experiments using a prototype system.

• 한국전자파학회논문지
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• 제25권9호
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• pp.895-902
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• 2014

본 논문에서는 CMOS $0.18-{\mu}m$ 공정을 이용하여 1.75 GHz 대역에서 동작하는 이단으로 구성된 CMOS 전력증폭기를 설계하였다. 무선통신시스템에 적합한 전력증폭기 설계를 위하여 ADS 모의실험을 통하여 전력이득, 출력 전력, 효율을 각각 28 dB, 27 dBm, 45 %로 설계를 하였다. 실제 제작된 전력증폭기의 성능은 전력 이득, 출력 전력, 효율은 각각 22.9 dB, 24.8 dBm, 41.3 %로 특성을 나타냈으며, 변조된 LTE(Long-Term Evolution) 신호에 대하여 인접 채널 누설비(ACLR)가 -30 dBc 이하를 만족하며, 전력 이득, 출력 전력, 효율이 각각 22.6 dB, 23.1 dBm, 35.1 %의 특성을 나타냈다.

• 한국정보통신학회논문지
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• 제9권2호
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• pp.438-444
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• 2005

우리나라 정보통신 이용현황은 2004년 6월말 기준 CDMA방식을 이용하는 이동전화 가입자는 약 3,601만, ADSL 방식 등을 이용하는 초고속 인터넷 가입자는 약 1,161만명으로 급속히 발전하였다. 하지만 이러한 정보통신기술(In . Information Communication Technology)의 발전과 이용인구의 비약적인 증가에도 불구하고 농어촌 및 섬에는 지형적, 경제적 이유로 대도시와의 정보격차가 현저하게 존재하고 있는 실정이다. 본 연구는 지형적, 경제적인 원인으로 인해 정보접근기회가 상대적으로 적은 정보소외계층이 많이 존재하는 섬 지역에 중점을 두어 정보통신망을 구축할 수 있는 정보통신기술을 살펴보고 섬 지역의 정보격차 해소를 위한 방안을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5381-5399
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• 2016

Currently, the quantize-and-forward (QF) scheme with high order modulation and quantization has rather high complexity and it is thus impractical, especially in multiple relay cooperative communications. To overcome these deficiencies, an improved low complex QF scheme is proposed by the combination of the low order binary phase shift keying (BPSK) modulation and the 1-bit and 2-bit quantization, respectively. In this scheme, the relay selection is optimized by the best relay position for best bit-error-rate (BER) performance, where the relays are located closely to the destination node. In addition, an optimal power allocation is also suggested on a total power constraint. Finally, the BER and the achievable rate of the low order 1-bit, 2-bit and 3-bit QF schemes are simulated and analyzed. Simulation results indicate that the 3-bit QF scheme has about 1.8~5 dB, 4.5~7.5 dB and 1~2.5 dB performance gains than those of the decode-and-forward (DF), the 1-bit and 2-bit QF schemes, at BER of $10^{-2}$, respectively. For the 2-bit QF, the scheme of the normalized Source-Relay (S-R) distance with 0.9 has about 5dB, 7.5dB, 9dB and 15dB gains than those of the distance with 0.7, 0.5, 0.3 and 0.1, respectively, at BER of $10^{-3}$. In addition, the proposed optimal power allocation saves about 2.5dB much more relay power on an average than that of the fixed power allocation. Therefore, the proposed QF scheme can obtain excellent features, such as good BER performance, low complexity and high power efficiency, which make it much pragmatic in the future cooperative communications.

• 한국농촌간호학회지
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• 제15권1호
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• pp.9-15
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• 2020

Purpose: The purpose of this study was to examine the effectiveness of smartphone use to enhance self-efficacy and decrease loneliness in elders through communication using the SNS Program Methods: Participants in this study were assigned to the experimental group (25) or control group (25). Data were collected from June 3 to July 12, 2019. For this study, the communication Program through SNS was run once for a total of 12 sessions. All data were analyzed using SPSS version 18.0 program, 𝑥² test, t-test, Repeated Measure ANOVA and Fisher's exact test. Results: It was found that H1 was supported (z=-4.12, p=.005) as "the experimental group participating in the communication Program through SNS had greater self-efficacy than the control group". H2 was supported as "the experimental group participating in the communication Program through SNS had less loneliness than the control group", (z=3.20, p<.001). Conclusion: This basic information may be used as an intervention on communication Program through SNS. Findings suggest the necessity of improving self-efficacy and reduction of loneliness through an intervention communication Program through SNS.

• 대한간호학회지
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• 제4권3호
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• pp.1-12
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• 1974

It is the purpose of this study to determine an effective method of communication between teachers and students. This study was done by using the theory, methods and tools of transactional analysis as developed by Borne and Harris. In order to achieve this objective: First; The teacher and student communication process is to be used, noting the student's reaction when the teacher uses "Adult" and "Parent" stimulus. Second; The effectiveness of the reaction toward the "Adult" and "Parent" stimulus is to be determined with these objectives in mind. The problems of this research study are as follows; What influence on the response of the student is brought about by the method of communication used by the teacher? 1) When the teacher uses the "Parent" Stimulus method what response of the student is shown? 2) When the teacher uses the "Adult" Stimulus method what response of the student is shown? 3) What method of communication helps to promote the student′s growth? In order to determine the answers to these questions data was collected from 40 first year students at a school of nursing in Inchon. These students were divided into two groups and the unstandardized interview technique was used to interview each student for ten minutes. A tape recording was made of each interview and the nonverbal communication was recorded by process recording immediately following each interview. The recorded material obtained from the two groups was analysed and then the Borne and Harris transactional analysis method was used in analysing the writer of this thesis undertook. Hypothesis 1. When the teacher used the "Parent" stimulus the student′s response was more frequently "Child" than "Adult", the results showed a significant difference of P〈0.001. Hypothesis 2. When the teacher used the "Adult" Stimulus the student′s response was more frequently of "Adult" than "Child", the results showed a significant difference of P〈0.001, The following conclusions are drawn from this study: 1) There is an indication that the teachers use of "Parent" stimulus communication is not an effective method to increase the growth of the student. 3) Since the teachers use of "Adult" stimulus resulted in an increase in the "Adult" response of the student there is ah indication that use of an effective communication method can help the student to develop. The writer of this research paper suggests for further study the following; 1) A comparison of the differences in response to the giving of both "Adult" and "Parent" stimulus to the same Students. 2) A comparison of the differences in student response to the communication method according to the student′s grade, age, sex and level in school.

• Journal of Astronomy and Space Sciences
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• 제39권3호
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• pp.109-116
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• 2022

The small-scale magnetospheric and ionospheric plasma experiment (SNIPE) is a mission initiated by the Korea Astronomy and Space Science Institute (KASI) in 2017 and comprises four 6U-sized nano-satellites (Korea Astronomy and Space Science Institute Satellite-1, KASISat-1) flying in formations. The main goal of the SNIPE mission is to investigate the space environment in low Earth orbit at 500-km. Because Iridium & GPS Board (IGB) is installed on the KASISat-1, a communication simulation is required to analyze the contact number and the duration. In this study, communication simulations between the Iridium satellite network and KASISat-1 are performed using STK Pro (System Tool Kit Pro Ver 11.2) from the AGI (Analytical Graphics, Inc.). The contact number and durations were analyzed by each orbit and date. The analysis shows that the average access number per day is 38.714 times, with an average of 2.533 times per orbit for a week. Furthermore, on average, the Iridium satellite communication is linked for 70.597 min daily. Moreover, 4.625 min is the average duration of an individual orbit.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.207-212
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• 2011

This paper presents a CPW-fed antenna with three slots. The proposed antenna can operate at 1.9~2.1 GHz and 2.9~3.3 GHz which are generated by the two rectangular slots, and 4.5~11.6 GHz which is generated by the main patch. The semicircle-slot is used as a band-notched filter to stop at a desired band (5.150~5.825 GHz) limited by IEEE 802.11a or HIPERLAN/2 applications. The currents concentrate around corresponding slots at the desired band. The proposed antenna is very small in size, with overall dimensions of $27{\times}32{\times}1\;mm^3$ etched onto an FR4-printed circuit board (PCB).

• 한국전자파학회논문지
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• 제22권9호
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• pp.897-903
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• 2011

본 논문에서는 InGaP/GaAs hetero-junction bipolar transistor(HBT)를 이용하여 900 MHz에서 동작하는 1 W급 선형 전력 증폭기를 설계 및 검증하였다. 온도 변화에 따른 증폭기의 특성 변화를 최소화하기 위해 능동 바이어스 회로를 구성하였다. 전류 붕괴(current collapse)와 열 폭주(thermal runaway)를 방지하기 위하여 ballast 저항을 삽입하여 전력 증폭기의 성능 및 신뢰성을 최적화하였다. 제작된 선형 전력 증폭기는 중심 주파수 900 MHz의 one-tone 신호를 사용하였을 때, 17.6 dB의 전력 이득과 30 dBm의 OP1dB를 가지며, 이때 44.9 %의 PAE를 갖는다. 또한, two-tone 신호를 인가하였을 때, 20 dBm의 평균 출력 전력에서 47.3 dBm의 매우 높은 OIP3를 갖는다.

• 한국해양공학회지
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• 제22권2호
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• pp.65-71
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• 2008

Recently, many researches in relation to data transmission with faster speed and greater volume, many researches have been carried out on sonar systems for underwater communication. According to these researches, an acoustic transducer for underwater communication requires wide bandwidth properties. In domestic researches for underwater communication sonar, an operating frequency in the range of $20{\sim}40\;kHz$ is used. In this paper, we propose anon-resonance type acoustic transducer for underwater communication. The TVR (transmitting voltage response) characteristics increased linearly as the frequency increased, and the RVS (receiving voltage sensitivity) characteristics were constant as the frequency increased. Traditional techniques for wide bandwidth transducershave a limit and a transmission loss difference at lower and higher frequency operating ranges. In this paper, the new transducer proposed decreased the transmission loss under some conditions. It was optimized with the FE analysis tool (ATILA) and evaluated using the TVR and the RVS characteristics in the range of $10{\sim}90\;kHz$. The value of TVR was 138 dB at 20 kHz and 148 dB at 40 kHz, and the differences was 12 dB. The value of RVS was $195{\pm}2\;dB$ and nearly constant. From theseresults, it is certain that the developed transducers can be used for an underwater communication network in the 1.3 km range with both a 20 kHz bandwidth and 30 kHz center frequency.