• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.535-538
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• 2004

마이크로폰을 이용하여 평면상에 직교형으로 배열된 음인 도래 방향 탐지 시스템을 구성하고, A/D 변환에 있어 일반저인 샘플링 기법과 spilt-beam형 어군 탐지 시스템에 적용된 4분 샘플링 기법을 이용하여 공기중에서의 음원의 토래 방향 탐지 성능에 관한 실험을 수행하였다. 일반 실내에서 단일 주파수의 음원에 대하여 직교형 마이크로폰 배열을 사용한 음인 토래 방향 탐지 시스템 및 4분 샘플링 기법의 적용이 유용함을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.603-603
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• 2013

3D 배열구조의 Vertical nanowire Integrated Nanogenerator (VING)은 낮은 출력, 유연 기판 상에 부적합, 나노선의 부서지기 쉬움, 장기 안정성, 균일한 나노선의 성장을 필요로 하는 문제점을 가지고 있다. 본 연구에서는 이러한 VING방식의 단점을 보완하여 2D 배열 구조의 Lateral nanowire Integrated Nanogenerator (LING)로 고출력 전압, 유연기판의 상에 적합 등을 개선하는 방향으로 연구를 하였다. 본 연구의 실험 방법으로는 RF magnetron sputter를 이용하여 AZO Seedlayer를 제작하였으며 제작된 AZO Seedlayer를 photolithography 공정으로 제작하였다. 패터닝된 샘플을 Hydro thermal synthesis method로 성장시켰다. 구조적 분석으로는 XRD, FE-SEM 등을 이용하여 측정하였다.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.80-86
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• 2010

Compressive Sensing (CS) has been widely studied as a promising technique in many applications. The CS theory tells that a signal that is known to be sparse in a specific basis can be reconstructed using convex optimization from far fewer samples than traditional methods use. In this paper, we apply CS technique to Multiple-input multiple-output (MIMO) radar systems which employ uniform linear arrays (ULA). Especially, we investigate the problem of finding the direction-of-arrival (DOA) using CS technique and compare the performance with the conventional adaptive MIMO techniques. The results suggest the CS method can provide the similar performance with far fewer snapshots than the conventional adaptive techniques.

• The Journal of the Acoustical Society of Korea
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• v.18 no.3
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• pp.27-34
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• 1999

This paper proposes an algorithm to design the non-linear array so as to form efficiently the one-shot beam with relatively less sensors for acoustic measurement. In this algorithm, according to the spatial sampling theory the part for high frequency(HF) band has equispaced sensor array and the sensor distances below the HF band are decided as a function of number of HF sensors. As the results of the simulations, the mean and variances of directivity index(DI) of non-linear array which has less sensors are similar to those of linear array. and the DI variation for beam steering angle is very small. And the beam width at -2dB point is 6.8°. Thus it is confirmed that the design algorithm for non-linear array which is proposed to have less sensors can be efficiently used in acoustic measurement.

• Journal of the Institute of Convergence Signal Processing
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• v.25 no.1
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• pp.1-6
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• 2024

The main function of intercept array sonar is to detect pulses radiated from enemy surface ships, submarines, and torpedoes. When a pulse is detected, it is a high risk situation for the own ship, so it is very important to find the target's location for the ship's maneuverability and survival. The target's location is calculated by finding the starting point of the pulse received form each sensor and calculating the time delay between sensors. In order to find starting point, the envelope of the signal is calculated and differential filtering is performed. However, since intercept array sonar has a high sampling frequency of the signal, the number of samples to be processed is large, so this process has a problem with a large computational amount. In this paper, we propose a pulse starting point calculation method using decimation for reducing computational amount. Simulations were performed while changing the decimation factor, and it was confirmed that computational amount was reduced. The proposed method is expected to be effective in real-time processing system and have advantages in resource utilization.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.183-190
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• 2013

The Photoplethysmogram is a similar periodic signal that synchrinized to a heartbeat. In this paper, we propose a exponential weight moving average filter that use similarity of Photoplethysmogram. This filtering method has the average value of each samples through separating the cycle of PPG signal. If there are some motion artifacts in continuous PPG signal, disjoin the signal based on cycle. And then, we made these signals to have same cycle by coordinating the number of sample. After arrange these cycles in 2 dimension, we put the average value of each samples from starting till now. So, we can eliminate the motion artifacts without damaged PPG signal.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.75-82
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• 2012

The Photoplethysmogram is a similar periodic signal that synchronized to a heartbeat. In this paper, we propose a periodic moving average filter that use similarity of Photoplethysmogram. This filtering method has the average value of each samples through separating the cycle of PPG signal. If there are some motion artifacts in continuous PPG signal, disjoin the signal based on cycle. And then, we made these signals to have same cycle by coordinating the number of sample. After arrange these cycles in 2 dimension, we put the average value of each samples from starting till now. So, we can eliminate the motion artifacts without damaged PPG signal.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.868-877
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• 2018

In this paper, we propose a new beamforming algorithm for a conformal array antenna based on support vector regression(SVR). While the conventional least squares method(LSM) considers all sample errors, SVR considers errors beyond the given error bound to obtain the optimum weight vector, which has a sparse solution and the advantage of the minimization of the overfitting problem. To verify the performance of the proposed algorithm, we apply SVR to the experimentally measured active element patterns of the conformal array antenna and obtain the weights for beamforming. In addition, we compare the beamforming results of SVR and LSM.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.221-229
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• 2002

In thin paper, error tolerance of each array element which satisfies error tolerance of beam pattern is decided by using the Monte-Carlo method. Conventional deterministic method decides the error tolerance of each element from the acceptance pattern by testing all cases, but this method is not suitable for the analysis of large number of array elements because the computation resources increase exponentially as the number of array elements increases. To alleviate this problem, we applied new algorithm which reduces the increment of calculation time increased by the number of the array elements. We have validates the determined error tolerance region through several simulation.

• Journal of Applied Biological Chemistry
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• v.62 no.2
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• pp.181-186
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• 2019

The optimum design of LED device for irradiation of 460 nm blue light on extruded rice cake using simulation and the effect of the blue light on the inactivation of Bacillus cereus (B. cereus) group on the rice cake were investigated. The irradiated light intensity patterns on the surface area of the sample were simulated with three different LED arrays (centered, cross, and evenly spaced) and at various distances (22, 32, 42 mm) between the LED modules and the sample. In addition, the uniformity was calculated as Petri factor. The evenly spaced array resulted the most uniform light intensity pattern in the simulation, and the Petri factor of 32 and 42 mm of the distances showed higher than 0.9, which represents the ideal uniformity of LED device. The bacterial population of the rice cake decreased to less than the initial bacterial population during exposure to LED blue light, whereas the bacterial population of the control sample increased. The bacterial count of the rice cake after blue light irradiation for 24 h was 1.21 log CFU/g lower than the control sample. Petri factor increased with increase of the distance between the light source and sample, however, the reduction rate of B. cereus group decreased. Therefore, the design of LED device, that represented the Petri factor higher than 0.9 and inactivated the population of B. cereus group, with evenly spaced and 32 mm of distance between the light source and sample was suitable for extending shelf-life of rice cake.