• Journal of Broadcast Engineering
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• v.28 no.1
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• pp.132-140
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• 2023

In this paper, we propose a method for performance enhancement of speech declipping using clipping detector. Clipping occurs when the input speech level exceeds the dynamic range of microphone, and it significantly degrades the speech quality. Recently, many methods for high-performance speech declipping based on machine learning have been developed. However, they often deteriorate the speech signal because of degradation in signal reconstruction process when the degree of clipping is not high. To solve this problem, we propose a new approach that combines the declipping network and clipping detector, which enables a selective declipping operation depending on the clipping level and provides high-quality speech in all clipping levels. We measured the declipping performance using various metrics and confirmed that the proposed method improves the average performance over all clipping levels, compared with the conventional methods, and greatly improves the performance when the clipping distortion is small.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.8
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• pp.61-66
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• 2008

Recently, portable devices which require small area and low power consumption employ applications using 3D graphics such as 3D games and 3D graphical user interfaces. We propose an efficient clipping engine algorithm which is suitable in 3D graphics pipeline. The clipping operation is divided into two steps: one is the selection process in the transformation engine and the other is the pixel clipping process in the scan conversion unit. The clipping operation is possible with addition of simple comparator. The clipping for the Y-axis is achieved in the edge walk stage and that for the X and Z-axis is performed in the span processing. The proposed clipping algorithm reduces the operation cycles and the area of of 3D graphics pipelines. We designed a 3D graphics pipeline with the proposed clipping algorithm using Verilog-HDL and verifies the operation using an FPGA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1076-1084
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• 2009

We propose an ATI (Adaptive Tone Injection) scheme based on clipping noise for PAPR (Peak-to-Average Power Ratio) reduction of OFDM (Orthogonal Frequency Division Multiplexing) signals. The proposed scheme is composed of three steps: clipping, tone selection, and TI procedures. In the first step, the peak samples in the IFFT (Inverse Fast Fourier Transform) outputs are scaled down by clipping. In the second step, the sub-carrier position where the power of the clipping noise is the maximum, is selected. Finally, the generic TI procedure is performed. Simulation results show that the proposed scheme does not require all the possible combinations of the original TI procedures, while maintaining the PAPR reduction performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.817-824
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• 2019

We propose an ATR (Adaptive Tone Reservation) scheme based on clipping noise for PAPR (Peak-to-Average Power Ratio) reduction of OFDM (Orthogonal Frequency Division Multiplexing) signals. The proposed scheme is composed of three steps: clipping, tone selection, and TR procedures. In the first step, the peak samples in the IFFT (Inverse Fast Fourier Transform) outputs are scaled down by clipping. In the second step, the sub-carrier position where the power of the clipping noise is the maximum, is selected. Finally, the generic TR procedure is performed. Simulation results show that the proposed scheme does not require all the possible combinations for the original TR procedures, while maintaining the PAPR reduction performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.44-51
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• 2008

In this paper, we propose a modified clipping scheme for iterative decoding of superposition coding system by losing less power than clipping scheme. Our proposed scheme in superposition coding system shows good performance in peak-to-average power ratio(PAPR) and system performance with the same Clipping Ratio especially in low Clipping Ratio case. Finally in order to alleviate the performance degradation due to clipping noises, we combine a soft compensation algorithm that is combined with soft-input-soft-output(SISO) decoding algorithms in an iterative manner proposed by [1][2]. Simulation results show that with the proposed scheme, most performance loss can be recovered.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.89-96
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• 2007

In this paper, we designed 3D graphics rasterizer with a culling and clipping for the efficient 3D graphics accelerator. The proposed rasterizer is implemented for the mobile system and process frustum culling, back face culling, Y-axis clipping and X-axis clipping. The rasterzier consists of triangle setup, edge walk and span process unit. Each unit of rasterzier is designed with a culling and clipping. It supports goraud shading with 16 bits depth values and 16 bits color values. The estimated performance of proposed rasterizer is 52M pixels per second.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.167-170
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• 1998

음성신호의 특징적인 성분인 피치를 검출하는 알고리즘 중 실시산 구현이 손쉬운 3단계를 클리핑 알고리즘을 PC상에서의 처리를 위하여 구현하였다. 이 알고리즘을 통하여 검출되는 피치의 안정성 및 정확성을 높이기 위해서 적용된 창함수, LPF, 클리핑 자기상관값계산, 비선형 감쇄, 등의 전처리 필터링과, 배수피치 검출 및 정정, 메디언 필터링을 사용하여 피치를 검출하였다. 또한 이 알고리즘을 이용하여 DSP의 도움을 얻지 않고 PC상에서 음성을 분석하여 스펙트로그램, 파형, 에너지, 피치 등을 출력하는 프로그램인 Visual Analysis Tool for sounds(VAT)의 출력화면을 통하여 피치검출을 나타내었다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.727-730
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• 2003

인터넷의 빠른 보급으로 많은 양의 정보가 유통되기 시작했다. 그러나 사용자들은 필요한 정보들을 취사 선택하기엔 정보들은 양이 너무 방대하다. 각종 사이트에 있는 뉴스들을 실시간으로 사용자들에게 필요한 정보를 제공할 수 있는 뉴스 클리핑은 이러한 사용자들의 요구를 충족할수 있다 하지만 기존의 뉴스 클리핑 시스템은 각 사이트에 접근 후, 수동적인 분석을 통해 뉴스 정보 및 뉴스 기사의 위치를 파악하고 이를 추출하도록 하는 시스템들이다. 본 논문에서 제안하고자 하는 시스템은 사이트의 구조를 파악하고, 뉴스 기사들을 동적으로 추출함으로써 기존 시스템의 단점을 극복하고, 내용 기반의 뉴스기사 검색이 가능하도록 한다.

• Journal of the korean veterinary medical association
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• v.45 no.6
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• pp.490-499
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• 2009

• Journal of the korean veterinary medical association
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• v.47 no.4
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• pp.295-303
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• 2011