• The Journal of the Acoustical Society of Korea
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• v.24 no.5
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• pp.294-300
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• 2005

Generally, traditional approaches to track the target position are to estimate ranges and bearings by 2-D MUSIC (MUltiple 519na1 Classification) method. and to associate estimates of 2-D MUSIC made at different time points with the right targets by JPDA (Joint Probabilistic Data Association) filter in the near field. However, the disadvantages of these approaches are that these have the data association Problem in tracking multiple targets. and that these require the heavy computational load in estimating a 2-D range/bearing spectrum. In case multiple targets are adjacent. the tracking performance degrades seriously because the estimate of each target's Position has a large error. In this paper, we proposed a new tracking algorithm using Position innovations extracted from the senor output covariance matrix in the near field. The proposed algorithm is demonstrated by the computer simulations dealing with the tracking of multiple closing and crossing targets.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.36-42
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• 2001

This paper propose new sound localization algorithm that detects the sound source bearing in a closed office environment using two microphone array. The proposed Subband CPSP (Cross Power Spectrum Phase) algorithm is a development of previously Down CPSP method using subband approach. It first split the received microphone signals into subbands and then calculates subband CPSP which result in possible source bearings. This type of algorithm, Subband CPSP, can provide more robust and reliable sound localization system because it limits the effects of environmental noise within each subband. To verify the performance of the proposed Subband CPSP algorithm, a real time simulation was conducted and it was compared with previous CPSP method. From the simulation results, the proposed Subband CPSP is superior to previous CPSP algorithm more than 5％ average accuracy for sound source detection.

• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.37-43
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• 2020

Smartphone-based localization has been widely studied in many different scenarios. But as far as we know, few work has addressed the problem of localization in underground public transportation systems, where GPS signal and wireless infrastructure are not always available. Knowing the location of a train is necessary to develop a useful service for subway passengers. And so, estimation of motion state and stop station by using sensors on a smartphone is being studied for subway passengers. This paper proposes a localization method that uses a barometer and a magnetic sensor on a smartphone. The method proposed in this paper first estimates whether the train runs or stops according to the change in air pressure and the strength of the magnetic field. The altitude value and the magnetic field value are then used to estimate the exact stop station of the train. We evaluated the proposed method using data from the Seoul's subway line 5. Compared with previous methods, the proposed method achieves higher accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.900-908
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• 2016

In this paper, we have studied the tracking system with a single channel monopulse receiver that has a comparative advantage of costs, size, weight, and power consumption over the general 3-channel monopulse receivers. After the single channel monopulse system was composed of an antenna, a monopulse receiver, a servo unit, a RF signal processor unit and a power supply unit, we analyzed the basic tracking performance of the tracking error angle and the pointing loss. And we proved the tracking performance to a moving target in the outdoor environment. On the Analysis of the tracking test results, the single channel monopulse system shows a equal or higher performance over the general 3-channel monopulse system and also has advantages of the system implementation. Also, it is concluded that this study is useful to apply a single channel monopulse receiver with benefits of production price and miniaturization when the monopulse tracking systems will be developed in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.466-474
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• 2014

According to wireless network technology and mobile processors performance were improved, the small wireless mobile device such as smart phones has been widely utilized. The mobile devices can be used GPS information, thereby the services based on location information was increased. GPS was impossible to provide location information in indoor and signal shading environment, and the tracking systems based on short distance wireless communication are required infrastructure. The IEEE 802.11 based tracking system is possible estimation using APs, however the tracking device is exhausted battery power seriously. In this paper, we propose IEEE 802.11 based low-power tracking system. We reduced power consumption from channel scanning and network connection. For performance evaluation, we designed and implemented the tracking tag device, and measured power consumption of the device. As the simulation result, we confirmed that the power consumption was reduced 46% compare to the standard execution.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.647-652
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• 2006

본 논문에서는 스마트 홈을 위한 실내 위치 추적 방법을 제안한다. 스마트 홈 환경에서 개인의 상황에 맞는 서비스를 제공하기 위해서 위치는 중요한 정보 중의 하나이며 최근에는 위치 정보를 확장하여 거주자의 행동 정보를 활용하여 거주자의 행동에 따른 서비스를 제공하는 것이 이슈가 되고 있다. 이를 위해서 제안된 적외선 기반 실내 위치 추적 시스템인 ubiTrack은 스마트 홈 내의 거주자로부터 거주자의 행동을 추론하기 위한 여러 컨텍스트 정보를 추출할 수 있다. 제안된 방법은 발신기, 수신기, 그리고 클라이언트 부분으로 나뉜다. 발신기는 천장에 부착되어 있는 적외선 발신기로부터 각각의 아이디를 가진 적외선 신호를 발생한다. 두 개의 적외선 수신 센서로 구성된 수신기는 발신기에서 발신된 아이디를 수신하여 클라언트 부분으로 보낸다. 클라이언트는 이 개별 아이디를 실제 위치정보로 전환하고 이를 활용하여 거주자의 방위와 속력 정보를 추출한다. 추출된 속력 및 방위 정보를 활용하여 거주자의 간단한 행동 정보를 추론할 수 있다. ubiTrack에서 추출된 이러한 정보는 거주자의 최종 행동 정보, 즉 거주자가 TV를 보려는지, 전등을 사용하려는지 등의 정보를 추론하는데 사용될 수 있다. 제안된 방법은 스마트 홈 테스트 베드인 ubiHome에 적용이 되었으며 몇 가지 실험을 통하여 거주자의 행동을 통하여 스마트 홈 환경에서 거주자의 행동을 통한 서비스 제공이 가능함을 보였다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.195-195
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• 1994

병원별 총 추적기간은 602-4,137 인년 이었으며, 병원별 대상자 1인당 추적일수의 중앙값은 34.5-61일 이었다. 병원별 추적 완료율도 35.3-92.3%로 다양하게 나타났다. 대상자중 칼슘차단제의 혈관확장효과에 따른 부작용들의 8주간 누적 발생율을 보면, 안면홍조 23.3%, 두통 13.5%, 심계항진 13.3%, 어지러움 7.6%, 하지부종 6.6% 였다. 그 외 부작용으로는 변비 13예, 소화장애 8예, 오심 6예, 치은비대, 안면부종, 피로감이 각각 2예, 탈모증, 불면증, 허약감, 피부질환, 호흡곤란, 손발저림, 발한, 구강건조 등이 각각 1예 있었다. 안면홍조의 발생율이 남자(12.9%)보다 여자(29.9%)에서 높았으며, 투여한 약제에 따라서 Nitrendipine 34.0%, Nifedipine 26,6%, Nicardipine 17.8%, Amlodipine 12.2%로써 약제별로 차이가 있었다. 두통의 발생율은 40세 미만 32.8%, 40-54세 15,8%, 55세 이상 10.5%로써 연령이 증가할수록 발생율이 낮았다. 하지부종의 발생율도 남자(3.4%)보다 여자(8.6%)에서 높았으며, 투여한 약제에 따라서 Nitrendipine 15.2%, Nifedipine 10.0%, Amlodipine 2, 1%, Nicardipine 0%로써 약제별로 차이가 있었다. 안면홍조가 발생한 환자에서 약물을 계속 투여시 2주후에 63.5%, 4주후에 77.0% 6주후에 88.5%가 소실하여 최초 안면홍조가 발생한 환자중 11.5%에서만 증상이 남아있었다. 약물투여를 중단하게 된 사유는 안면홍조와 두통이 각각 15예, 심계항진 4예, 어지러움 2예, 변비 및 안면부종이 각각 1예로 나타났다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.417-426
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• 2000

In this paper, CE-CPSK(Constant Envelope Continuous Phase Shift Keying) modulated DS/SS(Direct Sequence Spread Spectrum) transceiver with 908 MHz carrier frequency and 1.5 MHz PN clock rate is proposed. To overcome the effect of nun-linear power amplifier, CE-CPSK modulation method which has the constant envelope and continuous phase characteristics is proposed. To analyze the DS/SS receiver performance with respect to code tracking loop, multipath fading channel is characterized as a two-ray Rayleigh fading channel. To compensate the demerit of analog delay locked loop, digital delay locked loop is employed for code tracking loop. Simulation and experimental examination has been carried out in AWGN(Additive White Gaussian Noise) and Rayleigh fading channel environment in order to prove validity of the proposed method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.109-114
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• 2013

The biological active points (BAP) are known as low resistance spots or good electro-permeable points. In this paper, a new method for BAP detection using the bio-impedance measurement system based on the adaptive frequency tracking filter (AFTF) and the transition event detector is presented. Also, the microcontroller process continuous time demodulation of the modulated signal by multi frequency components using the AFTF. The transition event detector based on the phase space method is applied about each frequency using the BAP equivalent model which is proposed.

• The Journal of the Acoustical Society of Korea
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• v.24 no.6
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• pp.325-333
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• 2005

This paper proposes a geoacoustic inversion method for the experimental data or MAPLE 2004 experiment conducted in the East Sea of Korea in 2004 and shows source tracking test results to validate the Proposed inversion method. An objective function is defined as a correlation function of the measured and the simulated transmission loss data. The measured transmission data were obtained using a multi-tonal towed source and VLA. The VFSA (Very Fast Simulated Annealing) is applied to the inversion Problem which optimizes the objective function. After performing the inversion process for the S frequencies tonal data independently. geoacoustic models are constructed. Finally matched-field source tracking is Performed using the inverted parameters to verify them.