• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.6
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• pp.504-511
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• 2016

In this paper, the method is proposed that the equivalent result can be obtained by compensating the variation of gain and phase in the comparison with the result of near-field measurement which is obtained in the steady state, although the gain and phase variation of rx-channels occurred in the near-field rx-measurement of digital active phased array antenna. The proposed concept has the time section for monitoring the state of the rx-channels through the calibration path in the measurement timeline, and is the method for compensating the variation of state. For validating the proposed method, the fabricated X-band digital active phased array antenna and the planar near-field measurement facility is utilized. The proposed method is validated in the comparison with the compensated pattern which the unstable state of rx-channels is calibrated and the reference pattern obtained under the steady state of the rx-channels.

• Journal of Broadcast Engineering
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• v.22 no.1
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• pp.128-135
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• 2017

In this paper, the changes of broadcasting loudness before and after are measured for the major broadcasting channels according to the amendment of broadcasting law and enforcement of digital television broadcasting loudness technology standards. Before the implementation of digital television broadcasting loudness technology standards. all the channels to be measured were broadcast at a higher volume level than the technical standards. However, after the implementation, most of the channels to be measured were maintained at a loudness level suitable for the technical standards. However, some programs are inadequate to meet technical standards, requiring corrective action, and the need for additional research to improve the measurement method.

• Journal of Distribution Science
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• v.20 no.7
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• pp.107-117
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• 2022

Purpose: The scope of forensic investigations serves to identify malicious activities, including leakage of crucial corporate information. The investigations also identify security lapses in available networks. The purpose of the present study is to explore how to block distribution channels to protect illegal leakage in supply chain through digital forensic method. Research design, data and methodology: The present study conducted the qualitative textual analysis and its data collection process entails five steps: identifying and collecting data, determining coding categories, coding the content, checking validity and reliability, and analyzing and presenting the results. This methodology is a significant research method due to its high quality of previous resources. Results: Applying previous literature analysis to the results of this study, the author figured out that there are four solutions as an evidences to block distribution channels, preventing illegal leakage regarding company information. The following subtitles show clear solutions: (1) Communicate with Stakeholders, (2) Preventing and addressing illegal leakage, (3) Victims of Data Breach, (4) Focusing Solely on Technical Teams. Conclusion: There are difficult scenarios that continue to introduce difficult questions surrounding engagement with digital evidence. Consequently, it is important to enhance data handling to provide answers for organizations that suffer due to illegal leakages of sensitive information.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.175-178
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• 2003

This paper proposes a stereo image insertion technique on DCT coefficients using the embedded method developed in the digital watermarking in due consideration of compatibility with conventional 2D system such JPEG, and MPEG. In conventional transmission method users with conventional digital TV cannot watch the transmitted 3D image sequence as 2D image, because of affectivity of conventional 3D image compression. To give an answer, in this paper, DCT coefficients are changed according to its disparity on YCbCr channels. Our method can insert stereo images into a conventional image compression method based on DCT.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.98-110
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• 2008

Local cable channels has been contributing to settlement of grass root democracy and local business facilitation in decentralization era compared to other broadcasting media, and duly performs its role as local-tied media and produces local closeness type programs. But this is the time of need for change of perception by the producers, business entrepreneurs and relevant organizations on various production environment following process of conversion to digital cable TV. For successful settlement of local digital cable channels, this study has forecasted change on broadcasting production and organization following conversion of digital cable TV through the in-depth interview with people who produce and organize actual programs, and factors that interfere with digital cable TV conversion. Furthermore, the study learned plans to establish role and function of local cable channel as new close media to realize local value.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.229-232
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• 2000

Orthogonal frequency division multiplexing(OFDM) has meanwhile become part of several telecommunicati ons standards, such as satellite and terrestrial digital audio broadcasting(DAB), digital terrestrial TV broad casting(DVB), asymmetric digital subscriber line(ADSL) for high-bit-rate digital subscriber services on twisted-pair channels, and broadband indoor wireless systems. In his paper, we show that OFDM signals contain sufficient structure to accomplish blind channel estimation using second order statistics only. This method doesn't require redundancy as cp in transmitter. And the result is compared with PSAM channel estimation as least square, linear minimum mean square, singular value decomposition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.302-312
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• 2000

Digital TV tuner for 8-VSB modulation was developed with satisfying the requirements of ATSC. Double frequency conversion and active tracking filter was used in order to suppress IF beat and image band, which results in reducing the interference between adjacent channels and multi-channels. The implemented digital TV tuner has excellent performance such as the wide dynamic range, good flatness in passing band, and low phase noise. The developed tuner is available to handle the digital and analogue television signal at the same time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2456-2469
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• 1996

A digital satellite communication channel has a nonlinearity with memory due to saturation characeristis of the high poer amplifier in the satellite and transmitter/receiver linear filter used in the overall system. In this paper, we propose a complex radial basis function network(CRBFN) based adaptive equalizer for compensation of nonlinearities in digital satellite communication channels. The proposed CRBFN untilizes a complex-valued hybrid learning algorithm of k-means clustering and LMS(least mean sequare) algorithm that is an extension of Moody Darken's algorithm for real-valued data. We evaluate performance of CRBFN in terms of symbol error rates and mean squared errors nder various noise conditions for 4-PSK(phase shift keying) digital modulation schemes and compare with those of comples pth order inverse adaptive Volterra filter. The computer simulation results show that the proposed CRBFN ehibits good equalization, low computational complexity and fast learning capabilities.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.11-20
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• 2015

Digital watermarking provides electronic means for proving the copyrights of distributed digital media copies. Research on digital watermarking for images is recently directed toward that for color images extensively used in real life, based on the substantial results in digital watermarking for gray-scale images. Color images have multiple channels, each of which corresponds to a gray-scale image. While there are some watermarking techniques for color images that just apply those for gray-scale images to one channel of the color images, the correlation characteristics between the channels are not considered in them. This paper proposes a zero-watermarking technique that makes keys via combining an image dependent watermark, created through comparing two channels of the color image and copyright watermark scrambled. Due to zero-watermarking, it does not change anything of cover(host) images. Watermark images are robust against some common attacks such as sharpening, blurring, JPEG lossy compression, scaling, and cropping.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.19-24
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• 2017

Nowadays, based on the advancement of IT techniques, innovative products combining IT techniques to PA system are developing. In this paper, we presented the hybrid mixer controller for digital PA system. We develop the integrated mixer controller which includes the digital mixer composing an existing digital PA system and function of digital integrated controller. Developed integrated mixer controller consists of multichannel mixer function with 16 audio input channels, 8 output channels. And, it has an equalizer for processing digital audio signal, matrix and limiter. Also, the developed controller has some features such as internet connection for controlling of overall PA system and remote monitoring of mixer process condition.