• Title/Summary/Keyword: 김현석

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Characteristics of Filtered-X LMS Algorith for Two Tone Noise (두 정현파 소음에 대한 Filtered-X LMS 알고리즘의 특성연구)

  • 김현석;박영진
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.04a
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    • pp.16-21
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    • 1994
  • For the systems such as ANC(Active Noise Control) systems having auxiliary path after FIR type adaptive filter, Filtered-X LMS algorithm is effective. However behaviors of this algorithm has not been fully understood. The convergence property of this algorithm depends on not only cross correlation matrix between the filtered signals through model and real auxiliary path state solution of weight vector in Filtered-X LMS algorithm is investigated for under-determined case, over-determined case, and nonsingular case. Also, the convergence speed in case of two tone noise is investigated based on the eigenvalue spread of cross correlation matrix.

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The Literatual Study on the YOGA of Obesity (비만에 효과적인 요가(Yoga)자세에 관한 고찰)

  • Kim, Hyun suk;Yoon, Il ji;Choi, Seung Hoon
    • Journal of Haehwa Medicine
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    • v.13 no.1
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    • pp.279-285
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    • 2004
  • The results were obtained as follow: 1. Matsyasana and Dhanurasana in Yoga are effective for the whole body obesity. 2. Dhanurasana, Bhadrasana, Uddyanasana and Pahpuma Navasana in Yoga are effective for the abdomen and waist obesity. 3. Shalabhasana in Yoga are effective for the buttocks and thigh obesity. 4. Padangusthasana in Yoga are effective for the lower limb obesity. 5. Gomukasana and Adhomukhasana in Yoga are effective for the breast and shoulder obesity.

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A Case of Cervical Emphysema and Spontaneous Pneumomediastinum (경부 기종과 함께 발생한 자연성 종격동 기종 1예)

  • Kim, Hyeonseok;Choi, Hyo Geun;Park, Bumjung
    • Korean Journal of Head & Neck Oncology
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    • v.32 no.1
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    • pp.33-36
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    • 2016
  • Cervical emphysema and Spontaneous pneumomediastinum is an uncommon disease. Cervical emphysema is mainly caused by trauma or head and neck surgery. Here, we report a case of cervical emphysema and spontaneous pneumomediastinum in a 15-year-old man. This case emphasizes that cervical swelling patients with negative inflammation findings should be scrutinized for cervical emphysema and spontaneous pneumomediastinum.

Analysis of Lightning observed by KEPCO Lightning Detection Network (한전낙뢰관측 시스템 KLDNet의 낙뢰관측 결과 분석)

  • Kwak, J.S.;Park, M.H.;Jeong, M.J.;Ju, H.J.;Oh, S.Y.;Kim, H.S.;Woo, J.W.;Han, K.S.;Goo, S.G.
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.398-399
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    • 2015
  • The fault level of power transmission lines caused by natural disaster such as lightning and rainstorm has been on the rise. Especially, the cause of lightning stokes is large part of transmission faults. In order to reduce the lightning failures, it is necessary to measure and analyze the lightning characteristics. This paper deals with observation of the lightning strokes by KEPCO Lightning Detection Network(KLDNet) and analysis including lightning density, multiplicity and amplitude distribution.

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Free Vibration Analysis of a T Joint Using Thin-Walled Beam and Shell Elements (박판보 요소와 셸 요소를 이용한 T 조인트 진동 해석)

  • Kim, Jin-Hong;Kim, Hyeon-Seok;Kim, Yun-Yeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9 s.180
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    • pp.2334-2343
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    • 2000
  • This paper proposes an efficient beam-shell modeling technique for the free vibration analysis of a T-joint thin-walled beam structure. Except a small portion of a T-joint which is modeled by shell elements, the structure is modeled by thin-walled beam elements that can describe warping and distortion. In order to match the shell and thin-walled beam elements at the interface of the dissimilar elements, a technique based on a pseudo inverse matrix is formulated. This paper also examines the role of the thin-walled element taking into account the distortion and warping deformation degrees of freedom in predicting accurately the dynamic characteristics of a T-joint thin-walled structure.

A Study on Aesthetic Impression of Cinemagraphs Expressed in Advertising Media (광고매체에서 표현된 시네마그래프의 심미성 연구)

  • Kim, YoungIl;Kim, Hyeon-seok;Kim, Cheeyong
    • Journal of Korea Multimedia Society
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    • v.20 no.7
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    • pp.1129-1135
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    • 2017
  • Due to the development of the media, the digital image is gradually developed, giving some motion to the still image called Cinemagraphs, thereby enhancing the visual perceptional ventilation. In today's advertising media, visual stimuli are transmitted through Cinemagraphs. Demonstrate what is conveyed by aesthetics through case studies and experimental studies. In addition, through Cinemagraphs, the possibility of aesthetic technique is confirmed, and the features of Cinemagraphs will become a new trend in the field of design studying digital images. As IT technology becomes increasingly sophisticated and easy to make, it is expressed as a cultural symbolic pleasure of the masses. The value of future research will be significant.

Performance Analysis on the Initial Alignment of Laser Inertial Navigation System (레이저 관성항법장치 초기정렬 성능 분석)

  • Kim, Hyun-Seok;Kim, Cheon-Joong;Lee, Tae-Gyoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.5
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    • pp.622-635
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    • 2009
  • Laser Inertial Navigation System(LINS) consists of Ring Laser Gyroscopes(RLG) and accelerometers. RLG has a lock-in region in which there is zero output for input angular rates less than about 0.1deg/sec. The lock-in region is generated by the imperfect mirrors in RLG. To avoid the lock-in region, a sinusoidal motion called dither motion is applied on RLG. Therefore this dither motion is measured by RLG/accelerometer even if at a stop state. In this situation, the performance on the initial alignment of LINS can be degraded. In this paper, we analyze the performance on the initial alignment of LINS theoretically and experimentally. Analysis results include how dither motion, the pre-filter and the corner frequency in alignment loop affects the performance on the initial alignment of LINS.

Real Sound Interface for Virtual Reality (가상현실을 위한 실감음향 인터페이스)

  • Kim, Yong-Wan;Kim, Hyun-Suk;Kim, Hyun-Bin
    • Proceedings of the Korea Information Processing Society Conference
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    • 2000.10a
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    • pp.711-714
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    • 2000
  • 가상현실은 현실에 구애받지 않고 상상의 세계를 현실과 같이 만들어 내어 인체의 모든 감각기관이 인위적으로 창조된 세계에 몰입됨으로써 현실에 있는 것처럼 느낄 수 있는 사이버스페이스이다. 본 논문에서는 청취자의 머리움직임에 따라 머리 추적기로부터 수신된 정보로서 음향의 방향감 간의 상관모델을 구성하여 시스템내의 S/W 모듈에 전달하는 인터페이스와 이를 토대로 머리 움직임 변화에 부합되는 실감음향을 생성하고, 영상도 함께 동기화하여 몰입감을 증대시키는 실감음향 인터페이스에 대해서 논의한다.

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Analysis and Implementation of RFID Security Protocol using Formal Verification (정형검증을 통한 RFID 보안프로토콜 분석 및 구현)

  • Kim, Hyun-Seok;Kim, Ju-Bae;Han, Keun-Hee;Choi, Jin-Young
    • Proceedings of the Korean Information Science Society Conference
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    • 2007.10a
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    • pp.92-93
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    • 2007
  • RFID(Radio Frequency Identification : 무선주파수식별) 기술은 유비쿼터스 구조 기술의 중요한 한 부분을 이루고 있다. 태그를 이용한 모든 제품들이 이러한 서비스의 대상이 되고 있지만 불행이도 다방면에 이용되는 이면에는 사용자의 사생활과 사용자 밀 판매자간의 인증문제를 이용한 서비스 공격 대상이 되고 있다. 현재 이러한 RFID 시스템의 보안 메커니즘들은 매우 중요하며 본 논문에서는 여러가지 메커니즘들 중 보안 프로토콜을 이용한 사생활과 인증문제 해결을 위해 정형검증을 통해 분석하고 새로운 프로토콜을 제안 및 구현가능성을 언급하고자 한다.

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Cross-talk Canceler User Interface for Two-speaker 3D Sound Reproduction (2스피커 입체음향 재생용 크로스톡 제거기 유저 인터페이스)

  • 김현석;김풍민;서상원;김기흥
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 1998.11a
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    • pp.163-167
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    • 1998
  • 스테레오로 생성된 음향을 헤드폰을 사용하면 좌,우의 소리는 각각 좌,우의 귀로 상호 혼선 없이 전달된다. 그러나 2개의 스피커를 사용한다면 좌,우의 소리가 혼합되어 들린다. 이러한. 혼합현상을 크로스톡이라 하며, 이 경우 본래의 소리는 변질되어 들린다. 이러한 현상을 방지차기 위해 스피커로 재생하기 전 신호를 크로스톡 제거기를 통해 한번 더 처리하는 방법을 사용한다. 여기에 사용되는 크로스톡 제거기는 2개의 스피커와 청취자간의 상대 위치, 그리고 스피커와 청취자가 있는 방의 음향특성에 의해서 적절히 변화되어야 한다. 본 연구에서는 방의 음향특성이 무향실과 같다고 가정하고 2개의 스피커와 청취자간의 상대적인 위치가 주어졌을 때 효과적으로 크로스톡 제거기률 생성해주는 알고리듬을 제시하였다. 제안된 방법은 머리전달함수를 기반으로 하여 스피커가 청취자로부터 표준반경에 위치하였을 때의 크로스톡 제거기률 데이터 베이스화 하여 일반적인 거리에 위치하였을 경우에도 실시간으로 확장 적용할 수 있다.

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