• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2004.11a
• /
• pp.39-42
• /
• 2004

본 논문은 H.264 동영상 표준 부호화 방식의 성능 향상을 위한 잔여 신호 전처리 필터에 대해 제안한다. 영상의 화질에 대한 최종적인 판단은 인간의 시각에 의하므로 HVS(Human Visual System)을 영상 압축에 적용한 수 있다(1,2,3). 잔여 신호 전처리 필터는 원 영상으로부터 중요하지 않은 부분을 제거하여 영상의 화질을 주어진 비트율로 최대화 시켜 부호화 율을 향상시키는데 목적을 둔다(4). 부호화 방식의 형태에 따라 잔여신호(DFD: Displaced Frame Difference)에 잔여 신호 전처리 필터 알고리즘을 적용하여 노이즈를 제거하고 전송 비트율을 감소시킬 수 있다 제안된 방식의 성능을 실험 결과로부터 확인할 수 있다

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.3
• /
• pp.16-21
• /
• 2010

In this paper, the linear source and relay precoders are designed for AF MIMO relay systems. In order to minimize mean squared error (MSE) of received symbol vector, the source and relay precoders are proposed, and MMSE receiver which is suitable to those precoders is utilized at the destination node. As the optimal precoders for source and relay nodes are not represented in closed form and induced by iterative method, we suggest a simple precoder design scheme. Simulation results show that the performance of the proposed precoding scheme is comparable with that of optimal scheme and outperforms other relay precoding schemes. Moreover, in high SNR region, it is revealed that SNR between source and relay node is more influential than SNR between relay and destination node in terms of bit error rate.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.3
• /
• pp.264-273
• /
• 2002

Adaptive filters cannot exactly estimate the echo path of the receiving room because of the cross-correlation of stereo signals. In this paper, a new pre-processing method reducing the cross-correlation without degradation of stereophony is proposed to enhance the performance of stereophonic acoustic echo canceller. To reduce the cross-correlation, absolutes of two orthogonal signals derived from each channel signals are added to original channel signals. Assuming that the power of each channel signal is larger than that of the cross-correlation, the computation of pre-processing can be reduced. As results of simulations, it is shown that the performance of stereo acoustic echo canceller with the proposed pre-processing method is better than that of conventional ones.

• The Journal of the Acoustical Society of Korea
• /
• v.23 no.8
• /
• pp.597-601
• /
• 2004

This paper introduces a pre-rejection technique for wireless channel distorted speech with application to automatic speech recognition (ASR) Based on analysis of distorted speech signals over a wireless communication channel. we propose a method to reject the channel distorted speech with a small computational load. From a number of simulation results. we can discover that tile pre-rejection algorithm enhances the robustness of speech recognition operation.

• Proceedings of the KIPE Conference
• /
• 2014.11a
• /
• pp.150-151
• /
• 2014

HVDC 시스템의 안정적인 동작을 위해 보호 알고리즘이 요구된다. 보호 알고리즘에 사용되는 전력신호는 적용 알고리즘에 따라 필터링, RMS, RSS등의 전처리 과정이 필요하다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2000.04a
• /
• pp.141-144
• /
• 2000

스테레오 음향 반향 제거기는 채널신호간에 상호상관(cross-correlation) 때문에 적응필터 계수가 수신실의 반향 경로를 정확하게 추정하지 못한다. 본 논문에서는 상호상관을 줄이기 위해서 채널신호간 차의 절대값과 시변 감쇠상수를 이용하는 새로운 전처리 필터를 제안한다. 시뮬레이션을 통해서 제안하는 전처리 필터가 기존의 방법에 비해서 우수함을 보인다.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2076-2078
• /
• 2003

전력 케이블의 고장점 탐지를 상시 감시하고 있는 데이터로부터 on-line으로 할 수 있도록 하기 위한 전력 케이블 고장 신호의 전처리 기술 개발에 관하여 언급하였다. 고장 전류 파형을 모의하고 측정할 수 있는 케이블 고장 모의 측정 시스템을 구성하여 고장 전압과 전류 파형을 측정하였으며 측정된 신호로부터 고장점을 보다 정확하고 빠르게 연산할 수 있도륵 하기 위한 down sampling, filtering 등 전처리 과정에 대하여 시뮬레이션하고 그 결과에 대하여 논하였다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.20 no.4
• /
• pp.109-115
• /
• 2010

Differential Power Analysis (DPA) is well known as one of efficient physical side-channel attack methods using leakage power consumption traces. However, since the power traces usually include the components irrelevant to the encryption, the efficiency of the DPA attack may be degraded. To enhance the performance of DPA, we introduce a pre-processing technique which extracts the encryption-related parts from the measured power consumption signals. Experimental results show that the DPA attack with the use of the proposed pre-processing method detects correct cipher keys with much smaller number of signals compared to that of the conventional DPA attack.

• Journal of the Institute of Convergence Signal Processing
• /
• v.23 no.4
• /
• pp.249-255
• /
• 2022

Potholes are an important clue to the structural defects of asphalt pavement and cause many casualties and property damage. Therefore, accurate pothole detection is an important task in road surface maintenance. Many machine learning technologies are being introduced for pothole detection, and data preprocessing is required to increase the efficiency of deep learning models. In this paper, we propose a preprocessing method that emphasizes important textures and shapes in pothole datasets. The proposed preprocessing method uses intensity transformation to reduce unnecessary elements of the road and emphasize the texture and shape of the pothole. In addition, the feature of the porthole is detected using Superpixel and Sobel edge detection. Through performance comparison between the proposed preprocessing method and the existing preprocessing method, it is shown that the proposed preprocessing method is a more effective method than the existing method in detecting potholes.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.6
• /
• pp.629-636
• /
• 2022

We present a preprocessing method for an underwater target detection model based on a convolutional neural network. The acoustic characteristics of the ship show ambiguous expression due to the strong signal power of the low frequency. To solve this problem, we combine feature preprocessing methods with various feature scaling methods and spectrogram methods. Define a simple convolutional neural network model and train it to measure preprocessing performance. Through experiment, we found that the combination of log Mel-spectrogram and standardization and robust scaling methods gave the best classification performance.