• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.963-969
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• 2000

In this paper, we define two input-output gains of linear periodic time-varying systems. One is the ratio of output with worst-case l2-norm over all inputs with unit 12-norm. It denotes G($\iota_2,\iota_2$.The other is the ratio of output with worst-case RMS value over all inputs with unit RMS value. It denotes G(RMS, RMS) .It is fact that these two gains are equivalent for linear time-invariant system. In this paper, we prove these two gains are also equivalent for linear periodic time-varying system. In addition, the relationship between two method of obtaining the generalized frequency responses for linear periodic time-varying system is derived. Finally, we apply the defined input-output gains to M-channel filter-bank which is multi-rate signal Processing system, used to speech coding. In the filter-bank, generally, aliasing distortion, magnitude distortion, and phase distortion are present. It is shown that these are kept small if the filter-bank is designed by a method that optimizes the gain G($\iota_2,\iota_2$ of an error system.

• The Journal of Information Technology and Database
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• v.1 no.2
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• pp.71-102
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• 1994

현대는 고도 정보화사회(information society)로서 DB의 가치는 점점 증가하고 전반적인 DB 서비스는 일반적으로 많이 발전하여 우수한 정보 서비스가 제공되고 있다. 그러나 관광정보 DB서비스의 가치는 아직까지 거의 인식되지 않고 있는 실정이다. 따라서 본 연구에서는 초보단계에 있는 관광정보 DB서비스의 만족도를 측정함으로써 국내 관광정보 DB서비스의 수준을 파악하고 관광정보제공자에게 개선해야 될 문제점을 제시하고자 한다. 그러므로 관광정보 DB서비스의 개념을 정립하고 관광정보 DB서비스의 현황을 고찰하고자 Bailey와 Pearson의 연구에서 제시한 39가지 요인 중에서 관광정보 DB서비스와 관련된 요인을 추출하고 의미를 재정의하여 HiTEL의 이용자를 대상으로 첫째, 정보서비스의 메뉴별 선호도 둘째, 관광정보 DB서비스의 만족도 셋째, 관광정보 DB서비스의 각 메뉴별 선호도와 만족도 넷째, 이용자 특성별로 각 메뉴의 선호도를 비교분석 다섯째, 관광정보 DB서비스의 만족요인을 분석하였다. 관광정보 DB서비스의 전반적인 만족도는 평균치(4.0)보다 저조한 3.85로서 저조하게 나타나고 있다. 즉, 관광정보의 이해도(4.55)는 평균보다 다소 좋은 반면, 다른 관광정보의 만족도는 평균치 보다 저조하다. 특히 관광정보의 연결사정(3.68)과 관광정보의 제공속도(3.44)가 아주 낮게 나타났다. 한편 HiTEL이 제공하는 관광정보 DB서비스의 각 메뉴 중에서 가장 자주 이용되는 메뉴는 알림나라(40.2%)이며, 아시아나항공(22.5%), 농협일렉트로뱅크(13.7%), 대한항공(9.8%), 위너스 OK서비스(6.9%), MEET/매경SCOUT(6.9%)의 순으로 관광정보는 전반적으로 골고루 이용되고 있다. 또한, 메뉴별 관광정보 DB서비스의 만족도가 평균만족도보다 낮은 것은 알림나라(3.48), 농협일렉트로뱅크(3.84), 대한항공(3.90), 위너스OK서비스(3.95)로 나타났다. 그리고 각 메뉴별 이용자의 계층별 선호도는 첫째, 남성은 알림나라(40%), 아시아나 항공(23.16%), 농협일렉트로뱅크(12.63%)를 많이 이용하나, 여성은 알림나라(42.86%), 농협일렉트로뱅크(28.57%)를 주로 선호하는 것으로 나타났다. 둘째, 연령별 선호도는 나이가 많을수록 단순 관광안내정보인 알림나라, 농협일렉트로뱅크보다는 보다 항공관련 정보를 더욱 선호하는 것으로 나타났다. 셋째, 직업별 선호도는 학생과 사무직에 종사하는 사람이 가장 많은 메뉴를 이용하며, 전문직, 관리직, 기술직은 대체적으로 항공관련정보를 더 선호하는 것으로 분석되었다. 넷째, 학력별 선호도는 고학력자일수록 많은 메뉴를 이용하고 있으며, 다섯째, 가입시기별 선호도는 가입한 시간이 길어짐에 따라 항공관련정보를 선호하는 것으로 나타났다.

• The Journal of the Acoustical Society of Korea
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• v.25 no.4
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• pp.151-158
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• 2006

In this paper, we proposed a new audio fingerprint extraction method, based on Philips' music retrieval algorithm, which uses the energy difference of neighboring filter-bank and probabilistic characteristics of music. Since Philips method uses too many filter-banks in limited frequency band, it may cause audio fingerprints to be highly sensitive to additive noises and to have too high correlation between neighboring bands. The proposed method improves robustness to noises by reducing the number of filter-banks while it maintains the discriminative power by representing the energy difference of bands with 2 bits where the quantization levels are determined by probabilistic characteristics. The correlation which exists among 4 different levels in 2 bits is not only utilized in similarity measurement. but also in efficient reduction of searching area. Experiments show that the proposed method is not only more robust to various environmental noises (street, department, car, office, and restaurant), but also takes less time for database search than Philips in the case where music is highly degraded.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.305-306
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• 2022

In accordance with the Act on Punishment of Serious Disasters, terminal operators are required to establish and operate a safety and health management system such as manpower and budget necessary for disaster prevention, and establish and implement measures to prevent recurrence in the event of a disaster. This is a study on how to use the port facility safety management system linkage to prevent safety accidents in port facilities due to the introduction of autonomous driving port equipment and to support decision-making promptly in case of safety accidents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.92-99
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• 2002

Transient in an electric distribution system are mainly generated by switching. This paper presents analysis of switching surge and means of limiting the voltage magnification transient for high voltage power systems by using the EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor contraction capacitor banks to harmonics filters. An inductance in series with the capacitor bank was used to decrease the transient voltage at the customer bus to acceptable levels. And also simulation results used the EDSA harmonics analysis program show the effect of harmonics reduction.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.403-408
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• 2014

Lots of electric power has been wasted through the load bank usually in the container boxes during the generator load test of the ship and offshore plant in the new ship building. Therefore in this research, the quantity of wasted electric power through generator load test under construction was investigated on big shipbuilding yard and quantity of electric power that can be recovered is analyzed when produced electric power during the generator load test is connected to KEPCO Grid, according to laboratory's experiment result where recovers electric power produced from small generator connected to KEPCO Grid.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.277-282
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• 2018

This study aims to present a direction for securing continuous growth and confidence, centering on two Internet banking companies that started recently. The banking market has been rewriting the history since the emergence of Internet professional banks. In order to improve the credibility and promote the development of the Internet professional banks, I conducted a questionnaire survey and In Depth Interview. As a result of this survey, the overall reliability is still low, and the factors affecting reliability are: 1.Security problem 2.Discomfort of customer service 3.Errors and unnecessary services. This is a start-up business, so the awareness and reliability can be changed soon. Therefore, it is necessary to continue research on this according to the changing user's perception.

• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.347-355
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• 2000

This paper presents an adaptive AEC(acoustic echo canceller) based on the wavelet transform using M-channel subband QMF filter banks. The proposed algorithm improves the performance of AEC with a realtime process by a low complexity of wavelet transform filter banks, a subband processing and a orthogonality of wavelet subband filter. Adaptive filter coefficients of each subband are updated using LMS algorithm with a low complexity and a easy realization for a realtime processing and a reduction of hardware cost. For a input signal, a white Gaussian noise and a real speech signal with a environment noises are used for a performance estimation of the proposed algorithm. As a result of computer simulation, the proposed AEC has a low asymptotic error, a low computation complexity and a robust performance.

• 프린팅코리아
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• v.10 no.3
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• pp.104-105
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• 2011

한국잡지협회(회장 전웅진)은 자난 2월 15일 오후 1시부터 코엑스 컨퍼런스 센터 308호에서 회원사 CEO를 대상으로 한 '디지털 출판의 현재와 미래'라는 주체로 세미나를 개최했다. 한국어도비시스템즈의 최송현 부장의 환영인사에 이어 강진호 한국어도비시스템즈 이사가 '디지털 출판 워크플로와 비전'에 대해, 한덕훈 디지털웍스 팀장의 '인디자인 C55와 디지털 퍼블리싱 스위트 시연'을, 이국희 아이뱅크 대리가 '여성조선 및 북스동아 활용사례'에 대해, 황정호 한국어도비시스템즈 부장이 ACSP 2.0에 대해 소개했다. 이날 행사에서 이국희 아이뱅크 대리가 기존의 전자출판에서는 선보이기 힘들었던 다양한 기술을 소개한 '여성조선 및 북스동아 활용사례'가 큰 관심을 끌었는데, 약 20여분동안 질문시간이 이어지는 등 참가자들의 관심이 뜨거웠다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.1-7
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• 2000

In this paper, we proposed a complex multirate filter bank(CMRFB) based adaptive notch filtering technique to solve the co-existence narrowband interference problem of DS-CDMA and TDMA systems. We have discussed error performance of co-existence of DS-CDMA and TDMA system by using complex multirate filter bank in land mobile channel and computer simulation results show that the proposed scheme can eliminate the narrowband interference(TDMA signals) effectively.