• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.171-173
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• 2002

This paper presents a power system decomposition technique for digital simulation of large power system. To decompose power system, distributed transmission line model is used. But this model can be used only for long transmission lines. In this paper, capacitor compensation method is proposed to use distributed transmission line model for short transmission line. And case study shows proposed method can be used for effective power system decompositon in digital simulation of large power system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.838-841
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• 1993

This paper describes a fuzzy network circuit of analogue and digital mixed operation. The circuits are suggested for membership function, MIN function and normalization function using either linear voltage-controlled MOSFET resistance or pulse stream operation. The analogue-digital hybrid fuzzy hardware is extensible to the fuzzy-neural network as its basic configurations are already used in URAN-I of 135,424 synaptic connections.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.680-685
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• 1994

The acoustic phenomena in the actual sound systems involve a variety of compound problems. In this paper, the well-known Bayes' theorem is first employed and expanded into orthonormal and non-orthonomal series forms matched to the digital processing of lower and higher order statistical informations and the noisy observations. Proposed on-line algorithms of digital filter type are applied to the actual state estimation for a reverberation characteristics in a room under contamination of background noises.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.670-673
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• 2002

This paper proposes a digital algorithm for gray-scale/color image segmentation of real-time video signals and a cell-network-based implementation architecture in state-of-the-art CMOS technology. Through extrapolation of design and simulation results we predict that about 300$\times$300 pixels can be integrated on a chip at 100nm CMOS technology, realizing very high-speed segmentation at about 1600sec per color image. Consequently real-time color-video segmentation will become possible in near future.

• Journal of Korean Library and Information Science Society
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• v.39 no.4
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• pp.261-281
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• 2008

This study surveyed the retrieval systems for digital information resources of the university libraries in Busan, Ulsan, Gyeongnam districts and the vendors. Kinds of access points and retrieval conditions (Boolean logic, methods of index term identification, and particularities of the retrieval) of the libraries' systems are various and different to each other. Access points of the vendors' systems are unessentially various and different to each other, but the retrieval conditions are rather elaborated. Upon the result the suggestions for the standardization of digital information retrieval system are offered.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.6-8
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• 2009

In this paper. we propose receiver algorithms for VHF(Very High Frequency) digital link mode-2(VDL Mode-2) systems. Unlike conventional digital communication systems using the root raised cosine filter as a transmit and receive filter, raised cosine filter is used as a transmit filter in VDL Mode-2 systems. Hence, it is crucial to design and implement the optimum lowpass receive filter by considering the amount of inter-symbol interference and noise performance. On the other hand, due to the short preamble pattern, it is crucial to develop an efficient packet detection algorithm for reliable communication link. In this paper, we design the optimum receive filter and packet detection algorithm and evaluate the performance of receiver adopting the proposed receive filter and packet detection algorithm.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.373-374
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• 2008

지금까지 변전소나 발전소에서 전류, 전압을 계측하는 수단으로서 주로 철심과 권선으로 구성되어진 변류기(CT), 계기용 변압기(PT)가 사용되어져 왔다. 최근, 2차측의 계측기나 보호 Relay의 Digital 화가 진전되어져 있다. 또한, Digital Network로 총합한 Intelligent 변전소가 시범적으로 구축되어짐에 따라 Digital Network에 대응한 초고압용 신형 CT, VD가 요구되어지고 있다. 상기와 같은 요구로 인해 당사에서는 기존의 CT.PT의 단점을 보완할 수 있는 245kV GIS용 로고스키코일형 CT와 Capacitive Voltage Divider를 개발 중에 있으며, 센서 자체의 특성시험에서 IEC 60044-7, 8 1Class 기준을 만족하는 특성을 얻을 수 있었다. 이러한 신형 CT.VD의 적용으로 종래의 CT.PT가 차지하는 공간이 필요 없게 되어 컴팩트한 GIS의 구조가 가능하게 될 것이다.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.56-65
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• 1998

The multignature system is a digital contract system which can process multi-party contracts electronically. In this paper, we analyzed various insecure elements involved in general multisignature contract systems and suggest requirements needed for making such systems secure. Based on our analysis, we propose a new secure multisignature method and apply it to the conventional electronic digital contract systems along with several other existing multisignature methods. The applicability and the effectiveness of the newly developed method are demonstrated by comparing how well the suggested security requirements are satisfied by each method.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.18-21
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• 2007

Digital image watermarking is a technology used in copyrighting of digital images by embedding unremovable informations. In this paper, a pixel-domain look-up-table-based watermarking algorithm is presented. With this methodology, the watermark was embedded in the host image, but we did not observe any distortion at certain specific region of interest. This means the proposed method is preferred in case of satellite images. Then, the image manipulation tool which is called 'StirMark' will be used to perform many kinds of attacks such as rotation, scaling, filtering and compression on the watermarked image. Finally, the effectiveness of a watermarking technique in terms of 'robustness' and 'data integrity' criteria will be measured by calculating PSNR of watermark and watermarked image.

• Journal of Korea Multimedia Society
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• v.21 no.5
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• pp.638-647
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• 2018

This study aimed to identify visuality changes in the $21^{st}century$ digital visual media art through the expension of digital frames based on visuality represented by Cartesian perspectivalism in the modern age. The visuality of perspective, camera obscura and panorama, which are called modern visual systems, was analyzed to illustrate each characteristic from a viewpoint of a seeing subject. These characteristics of the visual systems were restructured to meet the visuality of the digital era through the illustrations of Lacan's gaze. In addition, the characteristics of frames found in the $21^{st}century$ digital visual media art were identified, and they were categorized into and illustrated from physical, convergent and interactional viewpoints. The outcomes were classified into the $21^{st}century$ digital frame types, and new $21^{st}$century digital visual illustrations were suggested based on the results.