• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.282-291
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• 2011

Adaptive modulation(AM) is an important technique to increase the system efficiency, in which transmitter selects the most suitable modulation mode adaptively according to channel state in the temporary and spatially varying communication environment. Fixed modulation on channels with varying signal-to-noise ratio(SNR) is that the bit-errorrate(BER) probability performance is changing with the channel quality. An adaptive modulation scheme can be designed to have a BER which is constant for all channel SNRs. The correct as well as fast and simple SNR estimation is required essentially for this adaptive modulation. In order to operate adaptive modulation system effectively, in this paper, we analyze the effect of SNR estimation performance to it through the average BER and data throughput. Applying SNR estimation based on auto-correlation of decision feedback signal and others to adaptive modulation system, we also confirm performance degradation or improvement of its which is decided by SNR estimation error at each transition point of modulation level. Since SNR estimation based on auto-correlation of decision feedback signal shows stable estimation performance for various quadrature amplitude modulation(QAM) comparatively, this can be reduced degradation than others at each transition point of modulation level.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.264-264
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• 2017

국외의 상수도 원격검침 시스템 내 데이터 전송방식은 도시 규모, 계량기의 밀도, 전력공급 여부 및 통신망의 설치 여부 등을 종합적으로 고려하여 결정되었다. 대부분의 스마트워터미터 제조업체들은 계량기의 부호기가 공급하는 판독 내용(데이터)을 전송할 검침단말기와 근거리 통신망(neighborhood area network)을 연계하여 개발 및 판매하였으며, 자체 소유 통신 프로토콜을 사용하여 라디오 주파수(RF) 통신 기술을 사용하고 있다. 광역통신망(wide area network)의 경우, 노드(말단의 계량기 및 센서)들과 이에 연결된 통신망 들을 포함한 네트웍의 배열이나 구성이 스타(star), 메쉬(mesh), 버스(bus), 나무(tree) 등의 형태로 통신망이 구성되어 있으나, 스타와 메쉬형 통신망 구성형태가 가장 널리 활용되는 것으로 조사되었다. 시스템 통합운영관리 업체들인 IBM, Oracle, Itron 등은 용수 인프라 관리 또는 통합네트워크 솔루션 등의 통합 물관리 시스템(integrated water management system)을 개발하여 현장적용을 하고 있으며, 원격검침 시스템을 통해 고객들의 현재 소비량과 과거 누적 소비량, 누수 감지 서비스 및 실시간 요금 고지 등을 실시간으로 웹 포털과 앱을 통해 제공하고 있다. 또한, 일부 제조업체들은 도시 용수공급/소비 관리자가 주민의 용수사용량을 모니터링하여 일평균 용수사용량 및 사용 경향을 파악하고, 누수를 검지하여 복구 및 용수 사용 지속가능성 지수를 제시하고, 실시간으로 주민의 용수사용량 관련 데이터를 모니터링하여 용수공급의 최적화를 위한 의사결정지원 서비스를 용수공급자에게 제공하고 있다. 최근에는 인공지능을 활용해 가정용수의 용도별(세탁용수, 화장실용수, 샤워용수, 식기세척용수 등) 사용량 곡선을 패터닝하여 profiling 기법을 도입해, 스마트워터미터에서 용수사용량이 통합되어 검지될 시 용수사용량의 세부 용도별 re-profiling 기법을 도입하여 가정용수내 과소비되는 지점을 도출 후 절감을 유도하는 기술이 개발 중이다. 또한, 미래 용수 사용량 예측을 위해 다양한 시계열 자료를 분석하는 선형 종속 모형(자기회귀모형, 자기회귀이동평균모형, 자기회귀적분이동평균모형 등)과 비선형 종속 모형(Fuzzy Logic, Neural Network, Genetic Algorithm 등)을 활용한 예측기능이 구축되어 상호 비교하여 최적의 용수사용량 예측 도구를 제공되고 있다.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.676-687
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• 2021

The main purpose of this study is to study the effect of a program to improve self-esteem and positive thinking in middle-aged women using Buddha Ball meditation. In order to achieve this research purpose, the subject of this study was middle-aged female Buddhists at Temple H in Busan who were interested in 'Buddha Ball'. For the analysis method, empirical analysis was performed using the One Group Pretest-Posttest Design of this study. The main research results are as follows. First, as a result of examining the effect of Buddha Ball meditation on the quality of life, it could be seen that the overall quality of life had a significant positive (+) effect on the experimental group. Second, as a result of examining the effect of Buddha Ball meditation on self-esteem, it could be seen that self-esteem had a significant positive (+) effect on the experimental group. Third, as a result of examining the effect of Buddha Ball meditation on positive thinking, it could be seen that the entire positive thinking had a significant positive (+) effect on the experimental group. Based on these research results, the main conclusion was that the Buddha Ball, a healing meditation tool using the sound wave energy, had a positive effect on the self-esteem and quality of life of middle-aged women Buddhists. Accordingly, it is judged that the Buddha Ball meditation program has a positive use value for middle-aged women who are experiencing more complex psychological difficulties due to individual, family, and social environmental conditions. In addition, by preparing a system that can actively utilize the Buddha Ball meditation program educationally and politically, the implications of the justification and necessity of using it to improve the self-esteem, positive thinking and quality of life of middle-aged women were presented.

• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.62-71
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• 2019

We conducted DC resistivity and MT survey to obtain the resistivity structure of the central Myanmar basin. We tried to analyze the underground structure through the resistivity variation of Myanmar by performing representative geophysical survey methods because researches on the electrical resistivity structure are insufficient in Myanmar. The electrical resistivity is expected to be low considering the marine sedimentary rocks composed of shale and sandstone in this area. The DC resistivity and MT survey were carried out using SmartRho of Geolux Co., Ltd. and MTU-5A of Phoenix geophysics Ltd., respectively, to visualize the electrical resistivity structure of study area. DC resistivity and MT survey showed an electrical resistivity less than dozens of ohm-m within the depth of 100 m. In particular, MT survey data were almost similar to TM and TE modes in the frequency range above 1 Hz. The two-dimensional inversion of MT data showed a subsurface structure with low resistivity below 150 ohm-m divided into east-west direction. We confirmed that the inversions of DC resisitivity and MT data along an overlapped survey line represented similar results. In the future, considering the high electrical conductivity, it would be effective to perform DC resistivity and MT survey simultaneously to study the electrical resistivity structure of the central Myanmar basin.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.115-123
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• 2018

Various types of robots running on power transmission lines have been developed for the purpose of line patrol monitoring. They usually have complex mechanism to run and avoid obstacles on the power line, but nevertheless did not show satisfactory performance for going over the obstacles. Moreover, they were so heavy that they could not be easily installed on the lines. To compensate these problems, flying robots have been developed and recently, multi-copter drones with flight stability have been used in the electric power industry. The drones could be remotely controlled by human operators to monitor power distribution lines. In the case of transmission line patrol, however, transmission towers are huge and their spans are very long, and thus, it is very difficult for the pilot to control the patrol drones with the naked eye from a long distance away. This means that the risk of a drone crash onto electric power facilities always resides. In addition, there exists another danger of electromagnetic interference with the drones on autopilot waypoint tracking under ultra-high voltage environments. This paper presents a patrol monitoring plan of autopilot drones for power transmission lines and its field tests. First, the magnetic field effect on an autopilot patrol drone is investigated. Then, how to build the flight path to avoid the magnetic interference is proposed and our autopilot drone system is introduced. Finally, the effectiveness of the proposed patrol plan is confirmed through its field test results in the 154 kV, 345 kV and 765 kV transmission lines in Chungcheongnam-do.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.204-216
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• 2021

This study empirically analyzed factors affecting consumers' intention to use metaverse by applying the extended technology acceptance model. In other words, the factors affecting the intention to use the metaverse were set as content quality, perceived enjoyment, social influence, self-efficacy, and investigated from the perspective of the expanded technology acceptance model. For this end, a survey was conducted on 296 university students in Seoul, and the collected data from 267 students were analyzed using SPSS 25.0 and AMOS 23.0. As a result, it was found that perceived usefulness and perceived ease of use, which are the antecedent variables of the extended technology acceptance model, affect the intention to use the metaverse, and perceived ease of use has an effect on perceived usefulness. Content quality and perceived enjoyment had an effect on perceived usefulness, perceived ease of use and intention to use metaverse. Social influence was found to affect perceived usefulness and intention to use metaverse. Also, self-efficacy was found to affect perceived ease of use and intention to use metaverse.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.640-645
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• 2021

The deep learning based end-to-end TTS system consists of Text2Mel module that generates spectrogram from text, and vocoder module that synthesizes speech signals from spectrogram. Recently, by applying deep learning technology to the TTS system the intelligibility and naturalness of the synthesized speech is as improved as human vocalization. However, it has the disadvantage that the inference speed for synthesizing speech is very slow compared to the conventional method. The inference speed can be improved by applying the non-autoregressive method which can generate speech samples in parallel independent of previously generated samples. In this paper, we introduce FastSpeech, FastSpeech 2, and FastPitch as Text2Mel technology, and Parallel WaveGAN, Multi-band MelGAN, and WaveGlow as vocoder technology applying non-autoregressive method. And we implement them to verify whether it can be processed in real time. Experimental results show that by the obtained RTF all the presented methods are sufficiently capable of real-time processing. And it can be seen that the size of the learned model is about tens to hundreds of megabytes except WaveGlow, and it can be applied to the embedded environment where the memory is limited.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.581-589
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• 2020

In this paper, a solid capsule was prepared using a crystal growth type inorganic material capable of hydration reaction, the quality and mechanical healing properties of self-healing mortar with solid capsules were evaluated. Solid capsules were mixed 5% by mass of cement. Reloading test results of compressive load, it was found to improve about 20% on average for the natural healing effect of Plain, in the case of the elastic range, the healing rate was about 79% at the 7 days of healing age and 98% at the 28 days of healing age. Reload test results of flexural load, in the case of the elastic range, the healing rate was about 79% at the 7 days of healing age and 98% at the 28 days of healing age. Through these results, it is judged that the healing performance of solid capsules has also an effect on mechanical healing properties such as strength in addition to the durability properties obtained by the permeability test. Since the strength tends to decrease as the solid capsules are mixed, it is considered necessary to compensate.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.11-23
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• 2020

Many former studies for the entrepreneurial intention dealt with the opportunity-driven motivation, but the actual entrepreneurial motivation is the necessity-driven motivation such as maintaining a living. It is necessary to study the necessity-driven factors for entrepreneurship such as employment barriers and job dissatisfaction. This study focused on the fact that the majority of cultural artists are freelancers or self-employed entrepreneurs. For those who majored in culture and arts, this study was conducted to investigate how an individual's internal and external environment affects the entrepreneurial intention considering the theory of planned behavior. I explored the factors that led individuals to choose entrepreneurial intention between employment and entrepreneurship, and studied the relationship between these factors and the entrepreneurial intention. As the result of the study, the job dissatisfaction and the employment barriers were the pressure factors for entrepreneurship. Job satisfaction had a negative effect on the entrepreneurial outcome expectation and the entrepreneurial intention. The perceived employment barrier had a positive effect on the entrepreneurial outcome expectation and the entrepreneurial intention. An individual's risk-taking orientation is one of the entrepreneurship and had the positive effect on the entrepreneurial self-efficacy. The entrepreneurial outcome expectation and the entrepreneurial self-efficacy had a positive effect on the entrepreneurial intention.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.266-269
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• 2022

As the emotional problems experienced by modern people after COVID-19 have increased, the burden on clients due to negative perceptions of psychological counseling and physical limitations is still high. Therefore, this study proposes a virtual counseling platform for effective counseling using the characteristics of people in their 20s who are open to relationships in non-face-to-face relationships. To this end, a survey was conducted for those in their 20s and in-depth interviews with counselors were conducted. After that, a 3D virtual counseling environment was created through Unity to PC-based service. As a result of the study, it was found that the most important factor in counseling in the 20s was the tendency of counselors and an atmosphere without burden, which was closely related to self-opening in counseling. Therefore, it was possible to participate in counseling while looking at the counselor character in a 3D space created in comfortable atmosphere, and various interaction elements with the counselor were provided during counseling. The significance of this study aims to promote self-openness of clients in their 20s and actively participate in counseling. This is expected to greatly help improve psychological problems through smooth counseling.