• Broadcasting and Media Magazine
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• v.15 no.1
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• pp.24-36
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• 2010

Nowadays, digital broadcasting providers have plan to extend their service area to 3D broadcasting without exchanging conventional system and equipments. The maintenance of backward compatibility to conventional 2D broadcasting system is very importance issue on digital broadcasting. To satisfy the requirement, highly-optimized MPEG-2 video encoder is essential for coding left-view and new video coding techniques having higher performance than MPEG-4 AVC/H.264 is needed for right-view since terrestrial broadcasting system has very limited and fixed bandwidth. In this paper, conventional video coding algorithms and new video coding algorithms are analyzed to present a capable solution for the best quality stereoscopic 3D broadcasting keeping backward compatibility within the bandwidth.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.151-159
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• 2015

In traditional programing education, computers were used as the main tool. Consequently, it was problematic to provide education in an environment without computers or for learners without computer skills. To address this problem, this study developed and validated an unplugged robot education system capable of computerless programming education. The key feature of the proposed system is that programing can be done only by connecting programming blocks in symbols of a flow chart with built-in commands. Validation of the system was performed by a specialist group. Validity was very high with values of content validity ratio (CVR) over 0.7 in all evaluation criteria except "Ease of error debugging" and "Linkages to educational curriculum," whose CVR values were each 0.6. Future directions include improvement in the two areas that scored lower than the others did by, respectively, system improvement to support debugging in error conditions that may occur during the programming process, and development of user guide to support linkages to educational curriculum.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.413-417
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• 2009

The use of scalable video coding scheme has been regarded as a promising solution for guaranteeing the quality of service of the video streaming over the Internet because it is a capable coding scheme to perform quality adaptation depending on network conditions. In this paper, we use a streaming model that transmits base layer using TCP and enhancement layers using DCCP, which try to provide transmission reliability of the BL and TCP friendliness. Unlike pervious works, the proposed algorithm performs rate adaptation based on playout buffer status. The PoB status of the client is sent back periodically to the server and serves as a network congestion indicator. Experimental results show that our scheme improves streaming quality comparing with pervious scheme in the case of not only constant/dynamic background flows but also VBR-encoded video sequence.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1477-1480
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• 2005

AOC-SS (Advanced Orthogonal Code-Spread Spectrum) modulation [1] is a flexible scheme to obtain a multi-rate transmission but PAPR (Peak-to-Average Power Ratio) increases in proportion to the number of AOCs and thus, the mapping technique is proposed to solve this problem. Moreover, by combining with space-time coding (STC), AOC-SS is capable of resistance to multi-path fading. The simulation programs have been performed to verify the validity of the suggested scheme.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.139-144
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• 2004

In order to transmit various types of multimedia data (i.e. voice, video, and data) over a wireless channel, the coding and modulation scheme needs to be flexible and capable of providing a variable quality of service, data rates, and latency. In this paper, we study a mobile multimedia COMA network combined with the concatenated Reed-Solomon/Rate Compatible Punctured Convolution code (RS/RCPC). Also, this paper propose the combination of concatenated RS/RCPC coder and COMA RAKE receiver for multimedia COMA traffic which can be sent over wireless channels. From the results, using a frequency selective Rayleigh fading channel model, it is shown that concatenated RS/RCPC coder at the wireless physical layer can be effective in providing reliable wireless multimedia CDMA network. And the proposed scheme that combine concatenated RS/RCPC coder and CDMA RAKE receiver provides a significant gain in the BER performance over multi-user interference and multipath frequency selective fading channels.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.370-373
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• 2004

The rapid proliferation of mobile device such as PDA allows users more ubiquitous access to multimedia information. The user mobility provides users a uniform vision of their preferred working environment independently of their current points of attachment. Supporting the user mobility requires the Player capable of efficiently presenting the multimedia contents. MPEC-4 provides not only the description for coding audio and video (as its predecessors MPEG-1 and MPEG-2), but also for coding images, animations, interactivity and protecting content. With MPEG-4, we present interactive media using multiple objects - audio, video, image, 2D geometry, and text - in a single format. Therefore we propose the MPEC-4 Player for PDA. The proposed MPEG-4 Player for PDA supports mobility, portability and personality.

• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.765-773
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• 2017

Ultra-high definition videos, panorama contents, and ultra-wide viewing videos have a huge spatial resolution. However, a whole region of images is not always interesting to viewers due to limitations of system resources and display devices. To allow one or more interesting tiles to be decoded freely without decoding other tiles, this paper introduces a tile-based independent coding method. The propose method restraints motion vectors to be within a tile region shifting motion search area and modifying an initial motion vector. Experiments results show that any desired tile is capable to be decoded independently of other tiles.

• Journal of Korea Multimedia Society
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• v.17 no.6
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• pp.706-715
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• 2014

It is used to lead to serious structural vulnerability of the system security of security-critical system when we have quickly developed software system according to urgent release schedule without appropriate security planning, management, and assurance processes. The Data Set and Provider of DataSnap, which is a middleware of Delphi XE2 of the Embarcadero Technologies Co., certainly help to develop an easy and fast-paced procedure, but it is difficult to apply security program and vulnerable to control software system security when the connection structure Database-DataSnap server-SQL Connection-SQL Data set-Provider is applied. This is due to that all kinds of information of Provider are exposed on the moment when DataSnap Server Port is sure to malicious attackers. This exposure becomes a window capable of running SQL Command. Thus, it should not be used Data Set and Provider in the DataSnap Server in consideration of all aspects of security management. In this paper, we study on the verification of the security vulnerabilities for Client and Server DataSnap in Dlephi XE2, and we propose a secure coding method to improve security vulnerability in the DataSnap server system.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.63-70
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• 2017

Recently, as user feedback such as social reading become active, demand has been increased on e-book contents making which is based on user feedback. However, to reflect the user feedback onto the e-book, direct coding is required, which was difficult to the author who was not good at programming. To resolve this problem, Block assembly style feedback editor system, using Blockly was developed. This editor enables to reflect the user feedback by area allocation, component allocation, block editing, and code generating insertion, contrary to the existing way of programming realization in which direct coding was required for input, processing and output separately. This system was developed by using HTML. Javascript, PHP, and Codeigniter. Block editing is enabled to do provision and assembly of blocks by Blockly. The function of code generation & insertion allows to insert the Library function code. Through this system, the general users who are not capable of coding also can reflect feedback without doing actual coding.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.4 no.2
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• pp.29-38
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• 1994

본 논문에서는 오류제어기능을 갖는 정보원 부호화 방식 중 Fibonacci부호와 flag부호에 대하여 알아보고, 부호화와 복호가 간단한 flag 부호에 있어서 비트 삽입 발생에 주목하여 최적의 suffix 패턴을 구한다. 이 최적 suffix 패턴을 사용한 제안부호의 성능을 비트 삽입 발생횟수의 확률적 해석과 컴퓨터 시뮬레이션을 통하여 비교 분석한다. 그 결과, 제안부호의 성능이 평균부호길이면에서 가장 우수한 Fibonacci부호 에 비해 동등이상의 결과를 얻을 수 있음을 보인다.