• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.326-332
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• 1996

In this paper, a method to design the sending loudness rating(SLR) is proposed and the desirable transmission characteristics are considered in order to specify the transmission quality, based on the loudness ratings, for the digital telephone system that is a terminal for digital speech communication. To specify the desirable SLR for digital telephone system, the subjective test defining the preferred range of inout level for CODEC was performed. From the test results, it was identified that the optimal input level for CODEC is -15dB and the range not to cause the quantization noise and the distortion of CODEC fall within -12dB and -18dB.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.31-33
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• 2011

방송 시청 중 한 채널에서의 프로그램 전환 혹은 시청 채널을 전환 할 경우, 프로그램 혹은 채널 간 오디오 레벨의 불균일은 시청자들에게 불편을 야기 시킬 수 있다. 특히 방송이 아날로그에서 디지털로 전환됨에 따라 이런 현상은 더욱 심각하게 발생이 될 수 있으며, 국가 간 고속 통신망의 확산에 따른 방송서비스 및 콘텐츠 배포 환경의 고도화로 인하여 디지털 방송 프로그램의 국제적 교환이 더욱 증대되어 디지털 방송 오디오 레벨의 균일화에 대한 중요성이 더욱 부각되고 있다. 본 연구는 이런 문제를 해결하기 위해 디지털방송 오디오 레벨 제어 관련 국내 현황을 조사하고, ITU-R 등 국제 표준화와 유럽 미국 등 외국의 대응 등에 대한 조사분석을 실시하고 국내 대응방안을 제안하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7A
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• pp.725-730
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• 2010

Preparing the conversion to the digital broadcasting system, we are deciding broadcasting network plan and interference protection area, using the measured receiving electric field level from the digital broadcasting station. However, the essential researches are needed about a receiving electric field level, because a digital TV (DTV) broadcasting receiver has been improved and an actual receiving environment should be considered. In this paper, the measured data were classified with domestic terrain of line of sight (LOS) and those of non-LOS, and effective receiving electric field level was proposed based on the LOS data. It is known that receiving electric field-level of 48 ㏈uV/m or more should be required for receiving rate of 90% and 50 ㏈uV/m for that of 95%, on the basis of the information of domestic terrain LOS.

• The KIPS Transactions:PartB
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• v.14B no.5
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• pp.337-342
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• 2007

Multi-level has advantage to express image in all levels with different images. This paper proposes digital watermarking built-in technique to transform color image to YCbCr color space to guarantee robustness and imperceptibility of the watermark in the various expression of color images, and to hide multi-level data which shows spread spectrum from low resolution to whole resolution for the Y-signal of multi-level. In color signal, Y-signal and low resolution built-in watermark has risk to be visible, but it can guarantee the robustness of watermark in various colors and transformed images. As a result of the experiment, wavelet compression image with built-in watermark showed robustness and imperceptibility of watermark.

• Explosives and Blasting
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• v.18 no.3
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• pp.77-82
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• 2000

현재까지 폭풍압은 음압과 음압레벨로 측정되어 왔다. 그러나 발파 소음에 의한 인체의 반응이나 가축의 피해 산정 등의 문제에서는 현행 소음진동규제법에서 명시하는 바, 인체의 청감보정이 이루어진 소음레벨을 사용하므로 변환문제가 발생한다. 본 연구에서는 발파 진동 계측기기로 계측한 데이터를 디지털 필터로 처리하여, 소음레벨로 변환하는 프로그램을 개발하고, 이를 실제 발파계측결과에 적용하였다. 그 결과, 국내에서 널리 사용되고 있는 Instantel Inc,의 Blast1ate series에서 계측된 소음데이터가 정밀도 높은 소음레벨로 변환이 가능하였다. 비슷한 정밀도로 계측결과를 ASCII file로 송출할 수 있는 기종에서 계측된 자료도 같은 정도로 처리할 수 있을 것으로 판정되었다.

• The Journal of the Korea Contents Association
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• v.17 no.6
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• pp.1-8
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• 2017

A smart leveling equipment was developed in this study by improving present leveling equipment. Both hardware and software of the equipment was developed and several accuracy tests of bench mark were conducted using various survey equipments. National control point (UO992-A), control points (15-00-06-24)-B and (15-00-06-23)-C were used for the accuracy test. As a result, the stable results in the range of errors were obtained in the cases of auto-level and digital level. Approximately 24mm error in the section of A-B and 26mm of B-C section was occurred in Smart Level equipment. This is due to the lack of technology completion and errors via relatively many numbers of installation tests. 46mm error of RMSE of smart level survey was occurred through the difference of section test. A small error was detected in short range but errors were accumulated far from the bench mark. It's concluded that an in-depth study emphasizing accuracy improvement can be practically applied to the various areas of industry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.966-982
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• 2014

This paper presents recent trends in system-level EMC investigation and countermeasure technology for radio frequency interference (RFI) influenced by noise generated in high-speed digital system. Recently, as the only digital device can perform various roles, there are a variety of EMI/EMC problems between systems. Especially, RFI is now recognized as a major problem, which occurs by EMI caused by the digital system. Therefore, in this paper, recent trends of RFI investigation from component-level to system-level are introduced and analyzed. Furthermore, in order to solve the RFI problem, recent researches are presented and investigated for the occurrences and suppression methods of common-mode noise which is one of the major noise sources in high-speed digital system. Lastly, this paper suggested future research of system-level EMC analysis and countermeasure technology for RFI problems.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.69-72
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• 2001

본 논문에서는 디지털 통신 시스템의 블라인드 등화에 있어서, 다중레벨 modulus를 기준 신호로 사용하여 등화기의 탭 계수 갱신 식에 사용되는 오차 신호를 형성함으로써 등화기의 블라인드 수렴 특성을 개선한 다중레벨 modulus 알고리즘들의 성능을 분석하였다. 다중경로 채널 하에서 QAM 신호점에 대해 컴퓨터 모의실험을 통하여 단일/다중레벨 modulus 알고리즘(SMMA)과 기존의 modified constant modulus algorithm(MCMA) 및 최근에 제안된 다중레벨 modulus 알고리즘(MMA) 등의 블라인드 수렴 및 정상 상태 성능을 비교하였다.

• Explosives and Blasting
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• v.21 no.1
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• pp.77-84
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• 2003

발파진동은 보통 지반진동속도로 계측되며, 발파설계나 구조물의 피해 산정에 사용된다 그러나 인체의 반응-이나 가축의 피해 산정 문제에서는 현행 소음진동규제법과 관련하여 인체의 감각적 감응척도에 따른 진동레벨을 주로 사용하므로 변환이 필요하다. 본 연구에서는 디지털 필터에 의한 진동레벨 변환 프로그램을 이용하여 진동의 특성이 따른 진동레벨 변환의 특성을 고찰하고 문제점을 제시하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.986-991
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• 2018

In this paper, an A/D conversion module was designed and fabricated to improve the dynamic range of wideband digital receivers. The A/D conversion module for expanding the dynamic range converts signals into a digital signal by branching the input signal into the normal path and the amplification path according to the input signal level. Test results of the fabricated module show that the normal path of the A/D conversion module converts an input level of -57 dBm to -12 dBm into a digital signal, and the amplification path converts an input level of -30 dBm to +12 dBm into a digital signal without distortion. This translates to an input dynamic range characteristic of 69 dB. Moreover, it is confirmed that the constant output characteristic is exhibited at an instantaneous bandwidth of 100 MHz.