• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.279-284
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• 2017

The localization of sources has a numerous number of applications. To estimate the position of sources, the relative time delay between two or more received signals for the direct signal must be determined. Although the GCC (Generalized Cross-Correlation) method is the most popular technique, an approach based on CCA (Canonical Correlation Analysis) was also proposed for the TDE (Time Delay Estimation). In this paper, we propose a new adaptive algorithm based on CCA in order to utilized the sparsity in the eigenvector of CCA based time delay estimator. The proposed algorithm uses the eigenvector corresponding to the maximum eigenvalue with log-sum regularization in order to utilize the sparsity in the eigenvector. We have performed simulations for several SNR(signal to noise ratio)s, showing that the new CCA based algorithm can estimate the time delays more accurately than the conventional CCA and GCC based TDE algorithms.

• The Journal of the Acoustical Society of Korea
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• v.37 no.6
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• pp.499-505
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• 2018

Time delay estimation between two acoustic sensors is widely used in room acoustics and sonar for target position estimation, tracking and synchronization. A cross-correlation based method is representative for the time delay estimation. However, this method does not have enough consideration for the noise added to the receiving acoustic sensors. This paper proposes a new time delay estimation method considering the added noise on the receiver acoustic sensors. From comparing with the existing GCC (Generalized Cross Correlation) method, and adaptive eigen decomposition method, we show that the proposed method outperforms other methods for a colored signal source in the white Gaussian noise condition.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.724-726
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• 1998

본 논문에서는 방대한 양의 데이터를 실시간으로 처리하기 위한 병렬 디지털 신호처리시스템을 제안한다. 버스와 메모리의 구조가 다른 네 가지 신호처리부 모델을 제안하고 그들의 성능을 분석한다. 신호처리부의 분석은 소나 알고리즘을 실행하는데 소요되는 하드웨어 지연시간과 버스 지연시간의 합을 척도로 한 성능 분석과 보드의 복잡도를 비교하는 방법을 통하여 이루어졌다. 성능분석한 결과, 지역 메모리와 공유 메모리를 함께 사용하는 모델이 가장 효율적인 것으로 나타났다.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.190-195
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• 1997

Medilog SAC847 수면종합분석시스템을 이용하여 침대와 온돌에서 성인 남 자가 수면시 피험자의 뇌전도, 턱근전도, 다리근전도, 심전도, 안전도(눈) 등의 생리신호를 동시 측정하여수면단계기록국제기준에 근거하여 NREM 4단 계와 REM 단계의 수면시간을 산정 하였다. 수면감을 평가하기 위하여 침대 와 온돌에서 수면시 입면지연시간과 NREM 단계4의 수면시간 비중을 고찰한 결과 침대수면이 온돌수면보다 입면지연 시간이 더짧게 나타났으며 나머지 NREM 4단계와 REM 단계에 소요된 수면시간은 서로 비슷하게 나타났다. 본 연구를 통한 수면생리신호 분석연구는 쾌적침대개발에 활용하고자 한다.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.43-43
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• 2004

국제적인 시각비교를 위해 GPS를 이용하고 있으나, GPS 신호에는 위성까지의 거리정보뿐 아니라 위성시계, 대류층, 이온층, 다중경로 오차 등이 포함되어 있다. 그 중 이온층 지연시간을 측정하기 위해서는 Ll과 L2 반송파 신호로부터 얻어지는 P코드와 위상정보를 이용할 수 있다. 반송파 위상 정보는 P코드보다 해상도가 좋기 때문에 위상정보를 이용하게 되면 고정밀도의 이온층 지연시간을 얻게 된다. 이온층 지연시간을 통해 총전자수를 나타내는 TEC 값을 얻을 수 있는데, 관측지점으로부터 시간에 따라 가장 높은 고도의 위성을 선택하여 P코드와 반송파 위상 정보를 통한 이온층 총전자수를 파악하고 정밀도를 비교분석 하였다. (중략)

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.2
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• pp.64-70
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• 2021

Nowadays, there are significant interests in real-time remote control using wireless networks. In implementing real-time remote control, one important factor is delay performance of real-time control message. Especially, the technique to reduce jitter of delay is necessary in transmitting periodically real-time control message. In this paper, we proposed synchronized transmission to reduce jitter of delay, when real-time control message was transmitted through wireless networks. The proposed transmission kept synchronization between source node and wireless transmitter and controlled transmission instance to transmit real-tie control message with fixed delay in wireless networks. According to results of experiment in military unmanned vehicle system, the proposed transmission reduced jitter of delay as 32% as that of a non-employing case.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.199-206
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• 2004

This paper proposes a hybrid independent component analysis(ICA) of fixed-point(FP) algorithm and robust algorithm. The FP algorithm is applied for improving the analysis speed and performance, and the robust algorithm is applied for preventing performance degradations by means of very small kurtosis and temporal correlations between components. And the adaptive adaptation of temporal correlations has been proposed for solving limits of the conventional robust algorithm dependent on the maximum time delay. The proposed ICA has been applied to the problems for separating the 4-mixed signals of 500 samples and 10-mixed images of $512\times512$pixels, respectively. The experimental results show that the proposed ICA has a characteristics of adaptively adapting the maximum time delay, and has a superior separation performances(speed, rate) to conventional FP-ICA and hybrid ICA of heuristic correlation. Especially, the proposed ICA gives the larger degree of improvement as the problem size increases.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.452-459
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• 2021

Estimating the mutual time delay between two acoustic sensors is used in various fields such as tracking and estimating the location of a target in room acoustics and sonar. In the time delay estimation methods, there are a non-parametric method, such as Generalized Cross Correlation (GCC), and a parametric method based on system identification. In this paper, we propose a time delay estimation method based on the parametric method. In particular, we propose a method that considers the noise in each receiving acoustic sensor. Simulation confirms that the proposed algorithm is superior to the existing generalized cross-correlation and adaptive eigenvalue analysis methods in white noise and reverberation environments.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.112-118
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• 2010

This paper describes a noise suppression system based on a normalization method using a time-delay neural network and line spectrum pair having a parameter of frequency domain. First, a time-delay neural network is trained using line spectrum pair values of noisy speech signals obtained by linear prediction analysis. After trained the time-delay neural network, the proposed system enhances speech signals that are degraded by a background noise. Accordingly, the proposed time-delay neural network restores from the line spectrum pair values of noisy speech signals to the line spectrum pair values of clean speech signals. It is confirmed that this system is effective for speech signals degraded by a background noise, judging from spectral distortion measurement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2A
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• pp.119-127
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• 2012

In this paper a super-resolution time delay estimation algorithm is developed for real-time locating systems (RTLSs) that employ a direct-sequence spread spectrum technique, along with its performance analysis in multipath environments. The classical correlation method provides relatively good performance in line-of-sight (LOS) environments but its performance seriously degrades in multipath environments, especially when signals are spaced closer than a PN chip. Therefore we shall develop a super-resolution time delay estimation algorithm that may estimate the time delays of multipath signals even in closely spaced multipath environments using the MUSIC algorithm for direction-of-arrival estimation and analyze its performance by applying the algorithm to the ISO/IEC 24730-2.1 RTLS system.