• 한국통신학회논문지
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• 제38C권9호
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• pp.746-756
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• 2013

TDOA (time difference of arrival)와 FDOA (frequency difference of arrival) 정보를 동시에 이용하는 신호원 위치추정 기법은 단일 정보를 이용하는 경우에 비해 높은 정확도를 가지는 장점을 가지고 있다. 이러한 위치추정 기법의 추정성능은 수신단 쌍의 조합, 수신단의 기하학적 배치 특성 및 속도 등의 다양한 운용변수에 따라 크게 달라진다. 그러므로 전자전 시스템의 효율적인 운용을 위해서는 다양한 운용 조건에 따른 사전 성능 분석이 요구된다. 하지만 기존의 비 반복적인 위치추정 방법은 기준 수신단의 설정 및 수신단 배치 형태에 제약을 가진다. 따라서 본 논문에서는 임의의 다양한 수신단 조합과 배치 형태에서 적용이 가능한 Gauss-Newton 기법을 유도하고 이를 통해 위치추정을 수행한다. 또한 모의실험을 통해 TDOA/FDOA 융합 기반 위치추정 방법과 단일 TDOA 또는 FDOA를 독립적으로 사용했을 때의 성능을 비교 분석하고 CEP (circular error probability) 평면을 이용하여 융합 기반 위치추정 방법이 독립적 방법에 비해 상대적으로 높은 추정 성능을 가짐을 보인다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.138-142
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• 2006

Time Difference of Arrival (TDOA) algorithm was applied to sound source positioning. Using measured microphones signal, difference of distance from source to sensors were estimated by TDOA and speed of sound, and taken by navigational measurements. And iteration procedures were induced to find the actual source location. For the case of stationary and moving sound source, validation test were performed in the anechoic room. In the stationary case, the error of positioning is less then 1.3% in length scale, and it could be seen proper filtering processes were required in the application of moving sound source.

• 수산해양기술연구
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• 제47권4호
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• pp.316-326
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• 2011

In this study, the entrapped number is investigated on the UV light with different illuminance to fluorescent bait cage for swimming crab in order to find the appropriate illuminance which has the best attraction effect of fluorescent bait cage for pots. In addition, preference to the light, arrival time and residence time at light area are compared and analyzed to fluorescent bait cage and non-fluorescent bait cage for American lobster at the UV light and ordinary light according to the illuminance condition. Pot with red non-fluorescent bait cage at the no lighting (<0.01lux), pot with blue fluorescent bait cage at the 20W UV lighting (0.16lux) and pot with blue fluorescent bait cage at the 30W UV lighting (0.22lux) were soaked for 6 hours and the entrapped number of swimming crab was examined. The mean entrapped number of swimming crab in pot with red non-fluorescent bait cage at the no lighting (<0.01lux) was 1.0, but the mean entrapped number of swimming crab in pot with blue fluorescent bait cages at the 20W UV lighting (0.16lux) and 30W UV lighting (0.22lux) were 1.4 and 0.4, respectively (P<0.05). The rate of preference to the blue fluorescent bait cage at the UV lighting shows 1.6-4.8 times higher than that of preference to the red non-fluorescent bait cage at the ordinary lighting. In addition, The rate of preference to the blue fluorescent bait cage at the UV lighting is higher when the illuminance of ordinary light is same as or is lower than that of UV light (P<0.05). However, the preference to the light depending on gender shows no significant difference (P>0.05). The arrival time to UV light area of lobster is shown as 1.2-2.4 times faster than that to ordinary light area. Generally, it is shown that arrival time to UV light area is faster than the arrival time to ordinary light area when the illuminance of ordinary light is the same as or lower than that of UV light (P<0.05). However, arrival time to the light area depending on gender shows no significant difference (P>0.05). The residence time at UV light area of lobster is 1.2-1.7 times longer than that at ordinary light area. The residence time depending on different illuminance of ordinary light and genders showed no significant difference (P>0.05).

• 말소리와 음성과학
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• 제3권3호
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• pp.109-114
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• 2011

To estimate sound direction of arrival with a pair of microphones, a method based on Time Difference of Arrival (TDOA) estimation using the Cross Power Spectrum Phase (CPSP) function is largely used due to its simplicity and good performance. In this paper, we investigate CPSP maximum values for various SNRs and adverse environments, and propose a novel method to improve the estimation performance of sound direction of arrival. The proposed method applies a threshold to the CPSP values and increases the reliability of the estimated sound direction. Through computer simulation for various SNRs, we validate the effectiveness of the proposed method. When the threshold was set to 0.1, more than 90% of success rate of sound direction of arrival estimation has been achieved for directions of $10^{\circ}$, $40^{\circ}$, $70^{\circ}$ from the source location even with reverberation times of 0.1s.

• 한국항행학회논문지
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• 제20권2호
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• pp.155-160
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• 2016

최근에 수중 음향통신에 대한 연구가 많은 연구자들에 의해 연구되어왔다. 수중 환경 UWAC를 사용하기 위해서는 두 신호들 사이의 시간차이를 추정하는 것이 필요하다. 일반적으로 두 신호 시아의 시간차이를 추정하는 기법으로는 배경 영역이 없는 시간을 추정하여 시간 차이를 추정하는 기법, 시간을 추정하여 두 신호 사이의 상호 상관을 추정하는 기법, 시간 차이 추정을 위한 위상지연을 추정하는 기법이 주로 사용된다. 본 논문에서는 UWAC에 적용하기 위하여 시간 지연 추정에 의한 두 신호 사이의 상호상관을 계산하고 이 상호 상관을 이용한 도착 시간의 추정 결과를 0.003055 초가 됨을 보인다.

• 한국음향학회지
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• 제36권6호
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• pp.378-386
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• 2017

해양무기체계 연구개발 과정에 있어서 정량적 시험평가를 수행하기 위해 수중에서 기동하는 표적과 계측 장비간의 거리측정이 요구된다. 일반적으로 정확하게 동기화된 송 수신기 사이의 전송 시간차를 측정하는 단방향 ToA(Time of Arrival) 기법을 이용하여 목표물의 거리를 측정한다. 하지만 수신된 신호는 다중경로의 영향으로 왜곡되어 거리 추정 성능을 저하시킨다. 본 논문에서는 음선 기반의 블라인드 디컨볼루션 기법을 사용하여 수신된 각 데이터 프레임으로부터 시변하는 복합 수중 채널 함수를 추정하고 추정된 시변 전달 함수를 시역전하여 다중경로 현상을 제거한다. 제안된 기법으로 시뮬레이션 및 해상실험을 진행하였을 때, 기존의 ToA 기법보다 거리 추정 성능이 향상되는 결과를 확인하였다.

• 한국항공운항학회지
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• 제22권3호
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• pp.8-14
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• 2014

Arrival management is a tool which provides efficient flow of traffic and reduces ATC workload by determining aircraft's sequence and schedules while they are in cruise phase. As a decision support tool, arrival management should advise on air traffic control service based on the understanding of human factor of its user, air traffic controller. This paper proposed a prediction model for air traffic controller sequencing strategy by analyzing the historical trajectory data. Statistical analysis is used to find how air traffic controller decides the sequence of aircraft based on the speed difference and the airspace entering time difference of aircraft. Logistic regression was applied for the proposed model and its performance was demonstrated through the comparison of the real operational data.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.9-12
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• 2001

In this paper, the natural space-time coding is applied for a DS-CDMA system with multiple transmit/receive antennas in a Rayleigh fading channel. With difference of arrival times from transmit antennas a modified maximum likelihood (ML) decoding algorithm is proposed for the space-time coded DS-CDMA system. The proposed decoding algorithm performs ML decoding over the transition of two consecutive branches by using a modified branch metric with the partial autocorrelation. By simulation, it is shown that the proposed decoding algorithm achieves significant performance improvement over the ML decoding algorithm without the modified branch metric.

• 한국군사과학기술학회지
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• 제21권4호
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• pp.447-455
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• 2018

If a hidden enemy is shooting, there is a threat against soldiers in recent conflicts. This paper aims to improve the localization of a muzzle using microphone array. Gunshot noise can provide information about the location of muzzle with two signals, the muzzle blast from the gun barrel and the projectile sound from the bullet. Two signals arrive to the microphone array with different arrival time and angle. If the arrival angles of the two signals are estimated, distance between sniper location and the microphone array can be calculated by using geometric principles. This method was established in 2003 by Pare. But this method has a limitation that it cannot calculate the distance when the arrival angles of the two signals are same. Also it has an error when the angle difference of arrival is small. In order to overcome this limitation, a new method is proposed that uses the change of characteristic of the projectile sound with respect to vertical distance from the trajectory. The proposed method estimates the distance correctly when the arrival angle of two signals are same, and when the angle difference between two signals is increased, the estimation error increases with respect to the angle. Therefore these two methods can be selected according to the angle difference between two signals to estimate the distance of the muzzle. Below the threshold of the angle difference, the proposed method can be used to estimate distance with smaller error than the existing method. This was demonstrated by shooting tests using actual sniper rifles.

• 한국군사과학기술학회지
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• 제14권4호
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• pp.694-699
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• 2011

A closed-form technique is presented for estimating a single source location from a set of noisy time delay measurements between distributed sensors. The localization formula is derived from nonlinear least squares minimization over the unknowns of target range and bearing in polar coordinates. Computer simulation results are provided for the purpose of performance analysis. Constrained least squares minimization method with prior source location information is also discussed.