• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1377-1380
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• 2003

계층적 모바일 IPv6는 이동 노드의 지역적인 이동시 보다 빠르고 효과적으로 서비스를 제공하기 위하여 네트워치를 계층적으로 구성한 프로토콜로써, 모바일 IPv6의 단점인 핸드오프시의 긴 지연시간을 단축시켜 손실되는 패킷을 줄이며, 외부로 전송되는 트래픽의 양을 감소시키는 장점이 있다. 따라서 많은 양의 데이타 처리가 필요한 멀티미디어 통신이나, 신속한 서비스를 필요로 하는 실시간 통신에 적용이 가능하다. 본 논문에서는 기존의 모바일 IPv6와 계층적 모바일 IPv6를 구현하여 핸드오프 지연시간과 패킷 손실량을 측정하고 성능 비교를 통하여 계층적 모바일 IPv6의 성능 향상을 확인하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.76-77
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• 2003

차세대 정보저장 기술중의 하나인 홀로그래픽 데이터 저장 기술은 빠른 데이터 접근속도와 기록 매질의 동일 위치에 수 천 페이지의 광정보를 중첩 기록할 수 있기 때문에 높은 저장용량을 갖는다. 이러한 홀로그래픽 데이터 저장을 위한 주요 구성으로 SLM(spatial light modulation)과 홀로그래픽 기록 매질을 들 수 있다. SLM은 전기적 신호를 광신호로 변조하기 위한 입력장치로 사용되며, 홀로그래픽 시스템에 사용되는 기록 매질은 고감도, 간단한 실시간 처리, 고회절효율, 기록 후 긴 안정성이 요구된다. (중략)

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.527-534
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• 2001

Conventional stereo image acquisition uses a pair of frame grabbers in the CAS(Computer Assisted Surgery) system. In this Paper, we developed a synchronized stereo image acquisition method with only one frame grabber Two images from left and right camera each other. were merged with different color space without time delay and thus only one frame grabber was enough toy stereo image. Due to this synchronous Property of image acquisition, we can improve spatial revolution on the computation of 3D Position. Furthermore the overall costs for 3D navigator can be down and the extraction time of stereo Position tan be shortened.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.853-855
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• 2018

현재 맥파(ECG; Electrocardiogram) 및 뇌파(EEG: electroencephalography)의 파형 분석기술은 다양하게 적용되고 있으니 이들을 종합적으로 활용한 개인용 건강서비스 개발은 아직 미비 한 상태이다. 본 논문에서는 측정대상자의 정신적 혹은 육체적 피로도를 나타내는 8가지의 지표로서 집중도, 전두엽 비대칭 정도, 좌우뇌 활성도 대칭 값, 알파파 및 베타파 훈련도 (이상은 뇌파 분석 결과), 스트레스 레벨, 심박 수, 자율신경균형도 (이상은 맥파 분석 결과)]를 개인에게 알려주는 생체정보기반 개인건강 관리 소프트웨어 시스템의 설계 및 개발 결과에 대하여 서술한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.1
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• pp.6-17
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• 2013

Recently, the color of vehicle license plate has been changed from green to white. Thus the vehicle plate recognition system used for parking management systems, speed and signal violation detection systems should be robust to the both colors. This paper presents a vehicle license plate recognition system, which works on both of green and white plate at the same time. In the proposed system, the image of license plate is taken from a captured vehicle image by using morphological information. In the next, each character region in the license plate image is extracted based on the vertical and horizontal projection of plate image and the relative position of individual characters. Finally, for the recognition process of extracted characters, PCA(Principal Component Analysis) and LDA(Linear Discriminant Analysis) are sequentially utilized. In the experiment, vehicle license plates of both green background and white background captured under irregular illumination conditions have been tested, and the relatively high extraction and recognition rates are observed.

• The Journal of the Acoustical Society of Korea
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• v.14 no.4
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• pp.46-63
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• 1995

This thesis described an unlimited vocabulary connected speech recognition system using Time Delay Neural Network(TDNN). The recognition unit is the diphone unit which includes the transition section of two phonemes, and the number of diphone unit is 329. The recognition processing of korean connected speech is composed by three part; the feature extraction section of the input speech signal, the diphone recognition processing and post-processing. In the feature extraction section, the extraction of diphone interval in input speech signal is carried and then the feature vectors of 16th filter-bank coefficients are calculated for each frame in the diphone interval. The diphone recognition processing is comprised by the three stage hierachical structure and is carried using 30 Time Delay Neural Networks. particularly, the structure of TDNN is changed so as to increase the recognition rate. The post-processing section, mis-recognized diphone strings are corrected using the probability of phoneme transition and the probability o phoneme confusion and then the eojeols (Korean word or phrase) are formed by combining the recognized diphones.

• Publications of The Korean Astronomical Society
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• v.34 no.3
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• pp.31-40
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• 2019

We study the internal structure under the artificial mountain of Heumkyeonggak-nu, a Korean water-powered clock in the early Joseon dynasty. All the puppets on the artificial mountain are driven by the rotational force generated by the water wheel at their designated time. We design a model that work with three parts of the artificial mountain. At the upper part of the artificial mountain to the east, west, north and south, there are four puppets called the Four Mystical Animal Divinity and four ladies called the Jade Lady respectively. The former rotates a quarter every double hour and the latter rings the bell every hour. In the middle part of this mountain is the timekeeping platform with four puppets; the Timekeeping Official (Hour Jack), the Bell-, Drum-, and Gong-Warriors. The Hour Jack controls time with three warriors each hitting his own bell, drum, and gong, respectively. In the plain there are 12 Jade Lady puppets (the lower ladies) combined with 12 Oriental Animal Deity puppets. In his own time a lady doll pops out of the hole and her animal doll gets up. Two hours later, the animal deity lies down and his lady hides in the artificial plain. These puppets are regularly moved by the signal such as iron balls, bumps, levers, and so on. We can use balls and bumps to explain the concept of the Jujeon system. Iron balls were used to manipulate puppets of the timekeeping mechanism in Borugak-nu, another Korean water-powered clock in Joseon dynasty, which was developed earlier than Heumgyeonggak-nu. According to the North Korea's previous study (Choi, 1974), it is obvious that bumps were used in the internal structure of Heumgyeonggak-nu. In 1669, The armillary clock made by Song, I-young was also utilized bumps. Finally we presented mock-ups of three timekeeping systems.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.8-14
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• 2016

High-level conceptual design analysis results of satellite communication system for Korea augmentation satellite system (KASS) satellite communication system, which is a part of KASS and consisted of KASS uplink Stations and two leased GEO is presented in this paper. We present major functions such as receiving correction and integrity message from central processing system, taking forward error correction for the message, modulating and up converting signal and conceptual design analysis for concepts for design process, GEO precise orbit determination for GEO ranging that is additional function, and clock steering for synchronization of clocks between GEO and GPS satellites. In addition to these, KASS requires 2.2 MHz for SBAS Augmentation service and 18.5 MHz for Geo-ranging service as minimum bandwidths as a results of service performance analysis of GEO ranging with respect to navigation payload(transponder) RF bandwidth is presented. These analysis results will be fed into KASS communication system design by carrying out final analysis after determining two GEOs and sites of KASS uplink stations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1013-1020
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• 2013

In this paper the super-resolution time delay estimation algorithms based on eigen-analysis are developed for spread spectrum signals along with their comparative performance analysis. First, we shall develop super-resolution time delay estimation algorithms using the representative eigen-analysis based AOA (angle-of-arrival) estimation algorithms such as MUSIC, Minimum-Norm, and ESPRIT, and apply them to the ISO/IEC 24730-2.1 real-time locating system (RTLS) employing a direct sequence spread spectrum (DS-SS) technique to compare their performances in RTLS environments. Simulation results illustrate that all the three algorithms can resolve multipath signals whose delay differences are even smaller than the Rayleigh resolution limit. Simulation results also show that MUSIC and Minimum-Norm provide a similar performance while ESPRIT is inferior to both algorithms in RTLS environments.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.543-547
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• 2002

We have constructed two extended-cavity diode lasers which are phase-locked with a 9.2 GHz frequency offset. We adopted a digital servo circuit for the phase-locking. The relative linewidth of the phase-locked lasers was less than 2 Hz. Using the measured beat spectrum, we found the carrier concentration to be about 93 %. We measured phase noise and relative frequency stability of the lasers. The Allan deviation at the gate time of 20 s was $2.7{\times}10^{-19}$.