• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.898-903
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• 2020

In this paper, we propose an indoor logistic tracking system that identifies the location and inventory of the logistics in the room based on fingerprints. Through this, we constructed the actual infrastructure of the logistics center and designed and implemented the logistics management system. The proposed system collects the signal strength through the location terminal and generates the signal map to locate the goods. The location terminal is composed of a UHF RFID reader and a wireless LAN card, reads the peripheral RFID signal and the signal of the wireless AP, and transmits it to the web server. The web server processes the signal received from the location terminal and stores it in the database, and the user uses the data to produce the signal map. The proposed system combines UHF RFID with existing fingerprinting method to improve performance in the environment of querying multiple objects.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.28-36
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• 2006

In this paper, an algorithm to classify the 4 motions of arm and a control system to position control the prosthesis are studied. To classify the 4 motions, we use flex sensors which is electrical resistance type sensor that can measure warp of muscle. The flex sensors are attached to the biceps brchii muscle and coracobrachialis muscle and the sensor signals are passed the sensing system. 4 motion of the forearm - flexion and extension, the pronation and supination are classified from this. Also position of forearm is measured from the classified signals. Finally, A two D.O.F prosthesis arm with RC servo-motor is designed to verify the validity of the algorithm. At this time, fuzzy controller is used to reduce the position error by rotary inertia and noise. From the experiment, the position error had occurred within about 5 degree.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.5
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• pp.21-29
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• 1999

이동횟수 기반 위치갱신 기법에서 고정망과의 접속은 단말 내부의 계수기가 이동횟수 임계치에 이르러 위치갱신이 수행되거나 신규호가 발생할 경우에 행해진다. 그러나 단말의 계수기가 임계치에 이르는 동시에 단말이 이전 위치갱신이 수행된 셀(중앙셀)로 재진입이 발생할 경우 불필요한 위치갱신이 수행된다. [2]에서는 중앙셀로 재진입이 발생하는 경우의 불필요한 위치갱신 수행을 제거하기 위해 중앙셀로 재진입이 발생할 경우 계수기를 영으로 초기화한다. 본 논문에서는 [2]의 기법을 일반화하여 위치갱신 비용을 절약할 수 있는 개선된 기법을 제안한다. 본 기법은 단말이 셀 사이를 이동하는 동안 단말은 자신이 방문한 셀과 이동횟수에 관한 정보를 저장한다. 단말이 이미 방문한 셀로 재진입이 발생할 겨우 이동횟수 계수기를 증가시키는 것이 아니라 이전 방문시 저장하였던 이동횟수로 재조정한다. 이러한 이동회수 계수기의 재조정 방법을 통하여 불필요한 위치갱신과 신호절차를 효과적으로 줄일 수 있다. [2]의 기법은 본 논문에서 제안하는 기법 중에서 중앙셀로 재진입할 때만 계수기를 영으로 재조정하는 특수한 경우에 해당된다. 본 기법이 전체 위치관리 비용을 크게 절약할 수 있음을 증명하기 위해 다양한 환경에서의 성능분석 및 수치적 결과를 통해 알아 본 결과 호 도착 비율당 전체 위치관리 비용이 평균 17-26% 절약됨을 관찰할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.555-558
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• 2015

본 논문에서는 체중계에 올라선 상태에서 발바닥 다섯 부위의 PPG 신호를 측정하고 분석하여 가장 강한 신호가 측정되는 최적의 위치를 찾기 위해 비교 실험하였다. PPG 신호는 스마트폰 카메라 측정하였고, 신호의 정확률을 비교하기 위해 발바닥과 손가락에서 동시에 PPG신호를 측정하였다. 발바닥과 손가락 끝에서 얻은 PPG 신호로부터 RRI를 산출한 후 Bland-Altman을 이용하여 유의성을 비교 분석하였다. 실험은 5명의 젊은 남녀를 대상으로 수행되었으며 실험결과 부위 1과 부위 2에서 높은 유의성을 보였다.

• Nuclear Engineering and Technology
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• v.21 no.4
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• pp.294-301
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• 1989

The Axial Power Distribution Monitoring System(APDMS) program was developed to calculate a detailed axial power distribution using two-level excore detector, cold leg temperature and control rod position signals. The unnormalized two-level excore detector signals were corrected for the rod shadowing factor determined by control rod position and for the temperature shadowing factor calculated based on cold leg temperature. A shape annealing matrix was then applied to the corrected excore detector response to yield peripheral power. After the core average power was obtained using linear relationship bet-ween core average and peripheral power, the boundary point power correction coefficient was applied to core average power in order to obtain boundary power for both upper and lower core axial boundaries. Then, the axial power distribution was synthesized by spline approximation. In spite of burnup, power level, control rod postion and axial offset changes, the comparisons of axial power distributions between BOXER simulation program and APDMS results showed good agreements within 5% root mean square error for Kori Unit 3 Cycle 4.

• Journal of Korea Multimedia Society
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• v.15 no.1
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• pp.71-80
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• 2012

LBS (Location Based Service) services are very useful to our daily life and it should be available inside a building: a huge building, a shopping mall, a large scale underground shopping center, and so on where GPS (Global Positioning System) signal is not available. An LBS which is provided inside a building is called an ILBS (Indoor Location Based Service). One of the most important techniques for ILBS development is indoor positioning. Among the indoor positioning techniques, APs (access points) of WLAN based ones are most economical because WLAN is available almost everywhere. Meanwhile, the web service has been proved to be an excellent practice of software reuse. Therefore, if indoor positioning is provided in the form of web service to programmers then development of ILBS would be greatly accelerated. This paper introduces the AP based trilateration and K-NN indoor positioning and RFID based indoor positioning web services we have developed.

• The Journal of the Acoustical Society of Korea
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• v.35 no.4
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• pp.310-318
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• 2016

This study deals with a method to localize a noise source occuring in a marine vehicle in a 3D environment. Even when access to the noise source is limited for a marine vehicle, such as a ship or a submarine in operation, the signal received on a hydrophone located elsewhere contains Doppler effected noise by moving relatively. This study suggests noise localization algorithm in 3D based on Doppler effect by moving marine vehicle. Using a known source mounted on the vehicle, the noise source was estimated by reducing the range of Doppler center and closest point of approach via the least square method. The algorithm was verified through various simulations and it was shown that the noise could be localized in 3D based on Doppler effect by employing two fixed hydrophones located at the vehicle's exterior points and a known reference signal generator located somewhere on the vehicle.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.379-381
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• 2009

본 논문에서 제안안하고 있는 긴급 SOS 시스템은 응급상황에 처한 사람의 위치를 빠르고 정확하게 추적하여 구조하는 위치기반 서비스이다. 제안된 시스템에서 일반상황에서는 근거리, 저전력 통신방식인 Zigbee Network를 사용하지만 응급상황 발생시 802.15.4의 Network를 이용하여 주변 핸드폰에 응급신호를 전송한다. 또한 전송된 응급 신호를 응급신호 추적기에서 수신하여 능동형 위치추적 알고리듬을 기반으로 위치를 추적한다. 본 논문은 제안된 긴급 SOS 시스템에서 배터리 소모를 줄이기 위한 프로토콜, 일반상황과 응급상황에 적합한 네트워크 구조를 제안하고자 한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.195-202
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• 2014

The Global Positioning System (GPS), which has various military and commercial applications, is designed to estimate the location of the specific user or object. In order to accurately estimate the location, GPS requires at least four satellite signals. The GPS receiver operates on extremely low signal-to-noise ratio (SNR) environment and it may suffer from various interference signals with the extremely high power. In this paper, we introduce a blind adaptive receiver based on the modified despreader, which suppress interference signals and detect GPS signals of interest without requiring explicit angle-of-arrival (AOA) information. We, also, provide the mathematical analysis for the signal-to-interference and noise ratio (SINR) of the modified despeader beamformer output. A representative computer simulation example is presented to illustrate the interference suppression performance of the considered GPS receiver and mathematical analysis of the SINR.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.435-436
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• 2012

실내에서는 GPS 신호를 수신할 수 없으므로 자신의 위치를 알 수 없다. 최근에 이러한 문제점을 해결하기 위하여 와이파이 엑세스 포인트(AP)를 이용한 실내 위치 정보 수집 방법들이 제안되고 있다. 본 논문에서는 AP를 이용한 이동체의 이동경로를 저장하는 시공간 데이터 모델 방법을 제안한다.