• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.347-360
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• 2005

E-Government service is national project that is necessary for international competitiveness, openness of government and effectiveness of governmental work process. E-Government security is very important because it treats data has relatively high sensitivity. But, until now, the development point of E-Government service has been limited to only it's contents and infrastructure based on web without consideration of E-Government security. Lately research for E-Government security has been studied by some advanced country of E-Government service, but it is insufficient. To construct E-Government security based on web Infra, first of all, analysis of web service security technology is needed to precede. And then research for appling the technology to E-Government service are required. We propose secure E-Government service scenario with web service security technology based on development stages of E-Government service. We also suggest overall view and secure scenario of E-Government service in Integrated Computing Environment.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.313-320
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• 2005

The increasing popularity of multimedia streaming services introduces new challenges in content distribution. Especially, it is important to provide the QoS guarantees as they are increasingly expected to support the multimedia applications. Multimedia streams typically experience the high start-up delay due to the large protocol overhead, the delay, and the loss properties of the wireless networks. The service providers can improve the performance of multimedia streaming by caching the initial segment (prefix) of the popular streams at proxies near the requesting clients. The proxy can initiate transmission to the client while requesting the remainder of the stream from the server. In this paper, we propose the traffic based caching algorithm (TSLRU) to improve the performance of caching proxy. TSLRU classifies the traffic into three types, and improve the performance of caching proxy by reflecting the several elements such as traffic types, recency, frequency, object size when performing the replacement decision. In simulation, TSLRU performs better than the existing schemes in terms of byte hit rate, hit rate, startup latency, and throughput.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1011-1018
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• 2006

Due to rapid development of mobile communication terminals and various requests of their users, multimedia information including image information has been the basis of mobile communication contents. In order to use vectored image information efficiently, which is more favorable than bit-mapped image information when transmission delay time and costs are considered, efficient vector graphics supporting systems are needed. Therefore, vector graphics kernel systems have been proposed and standardization attempts have been made in order to increase interoperability. In this paper, a vector graphics kernel based on OpenVG is designed and implemented. OpenVG was proposed as a standard vector graphics kernel by Khronos Group recently. The implemented vector graphics kernel, named by alexVG, is developed on a PC emulator as well as on a development board equipped with an ARM processor. In addition, performance tests are made in order to verify its functions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.592-599
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• 2007

The advancement of wireless technology improves the electronic learning by combining with the mobile function, and promotes the expanded transition to the mobile learning. Basically, the mobile learning provides the usefulness in terms of tile and space to provide learners with the access to the educational contents. However, the small display device and limited memory space of mobile device is limiting the access to the learning contents simply to the text-based transmission. This paper designed and implemented the multimedia mobile learning system that reduces the size of parser by define into MSMIL composed only of needed tag to multimedia contents production in the mobile devices by using the SMIL that supports the multimedia object synchronization reduces the data of multimedia learning data and enhances the transmission efficiency by applying the macro method in creating the contents of learning. The results of implementation indicates that it simplifies the designing language, makes the language learning easy, and saves the CPU resources for the parsing by reducing the size of parser.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.375-375
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• 2018

세계 수자원 시장은 연평균 6.5%씩 증가하고 있으며, 2025년 기준 1,038조원까지 급성장할 것으로 전문가들은 예상하고 있으나, 기후변화의 가속화로 인해 가뭄 및 홍수피해가 증가하여 수자원 관리가 더욱 어려워져지고 있다. 급속도로 변화는 환경에 대비하기 위해 국내에서는 수자원 및 기후변화에 대한 다양한 연구가 진행되고 있으나, 해외사업 진출 시에는 수자원 기초자료 수집에 대한 어려움을 겪고 있다. 이를 해결하기 위해 글로벌 수문기상자료 제공과 함께 GIS정보, 댐 및 저수지 관련 자료, 인문사회 자료, 물관련 통계자료, 물관련 재해자료 등을 웹으로 제공하는 글로벌 수자원 정보 시스템(GWB, Global World Bank)을 개발하고자 한다. 본 연구에서는 시스템의 통합 DB를 구축하고 관리방안을 도출하기 위해 수집된 메타데이터 속성 및 데이터구조를 파악하고, 세부항목별 자료 포맷을 분석 후 GIS기반 관측소 정보와 자료를 매칭하여 최종적으로 시스템 컨텐츠별로 DB를 맵핑하였다. 강수량과 기상자료는 33개국의 관측소 6,531개소의 일/월/연단위 관측자료와 10,977격자의 격자분석자료를 구축하였다. 수문자료는 33개국의 수문관측소 2,242개의 월/연단위 유량관측자료와 10,977격자의 월/연단위 직접유출, 기저유출, 잠재증발산의 격자분석자료를 구축하였다. 그리고, 수집된 강우와 기상자료는 기계 오작동, 자료 전송 오류 등으로 인한 결측치 및 이상치에 대해 자료품질분석을 통해 오자료에 대한 보정을 진행하였다. 해당자료는 MySQL를 활용하여 DB를 구축하였으며, GIS정보는 GeoServer를 활용하여 운영서버에 구축된 정보를 최종적으로 사용자에게 Web Browser로 표출하였다. 해당 시스템은 추후 전지구 수자원관련 정보를 제공하여 해외사업지역의 댐이나 보 등의 구조물 설계, 수자원산업의 해외 진출시 데이터 수집의 한계점 및 시간단축을 해결할 수 있어 수자원 분야에 기여 할 수 있을 것으로 판단된다.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.29-36
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• 2004

As the number of Internet users and the amount of web contents have increased very fast, reducing the load of web servers and providing web services more rapidly have been great issues. A web-cache system, which is located between the user and the web server, has been used by many web service providers as an effective way to reduce the load of web servers and the web service response time. In this paper, we have developed a web-cache system which is based on the Squid cache and has a compression capability. The web-cache system in which compression capability reduces the amount of network traffic and the web service response time by transfering the web contents in the compressed format over the network between the web-cache system and the user. The performance enhancement is greater in the reverse-cache system than in the forward-cache system because in the case of the reverse-cache system, the cache reduces the amount of traffic on the Internet which is the bottleneck in the network path between the user and the web server. The experimentation result shows that the amount of data traffic has reduced from 2 to 8 times depending on the size of the web contents. The web server response time has reduced 37% on the average and when the size of the web content is greater than 10Kbyte, the response time has reduced 87% on the average.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.151-156
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• 2013

Android that was made by Google and Open Handset Alliance is the open source software toolkit for mobile phone. In a few years, Android will be used by millions of Android mobile phones and other mobile devices, and become the main platform for application developers. In this paper, the integrated login application based on Google's Android platform is developed. The main features of the mobile combination login application content based on Android are as follows. First, the application has more convenient login functionality than the functionality of general web browser as the web browser of the mobile-based applications(web browser style applications) as well as security features and faster screen(view) capability by reducing the amount of data transfer. Second, the application is so useful for management of ID and Password, and it can easily manage multiple ID information such as message, mail, profile. The results of performance evaluation of the developed application show the functionality that can login many kinds of portal sites simultaneously as well as the ability that can maintain login continuously. Currently, we are trying to develope a couple of the technologies that can insert multiple accounts into one ID and check all information on one screen.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.866-876
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• 2014

Generating of digital hologram of video contents with computer graphics(CG) requires natural fusion of 3D information between real and virtual. In this paper, we propose the system which can fuse real-virtual 3D information naturally and fast generate the digital hologram of fused results using multiple-GPUs based computer-generated-hologram(CGH) computing part. The system calculates camera projection matrix of RGB-Depth camera, and estimates the 3D information of virtual object. The 3D information of virtual object from projection matrix and real space are transmitted to Z buffer, which can fuse the 3D information, naturally. The fused result in Z buffer is transmitted to multiple-GPUs based CGH computing part. In this part, the digital hologram of fused result can be calculated fast. In experiment, the 3D information of virtual object from proposed system has the mean relative error(MRE) about 0.5138% in relation to real 3D information. In other words, it has the about 99% high-accuracy. In addition, we verify that proposed system can fast generate the digital hologram of fused result by using multiple GPUs based CGH calculation.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.727-730
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• 2001

초고속 인터넷 서비스의 확대에 따라 이를 교육에 직 간접적으로 응용하기 위한 노력이 지속적으로 진행되어 왔다. 특히 웹 기반의 가상강의 저작도구를 통한 웹 코스웨어는 원거리 학습자들의 학습 욕구를 자기 주도적인 학습을 통해 가능케 했고 기존의 텍스트, 사운드를 통한 가상강의에서 동영상이 가미된 주문형 교육 서비스(EOD: Education On Demand)가 가능해졌다. 그러나 이를 이용하는 학습자는 전체적인 모듈의 이해를 통해 수업이 진행됨에 따라 학습과정에서는 질의응답을 튜터를 통해 웹 캐스팅이 이루어졌다. 따라서, 질의응답은 텍스트 형식의 E-mail, 채팅, 게시판, 방명록을 통해 이루어지므로 학습자가 요구한 질의 내용을 잘못 이해하고 튜터가 학습 과정에서의 피드백을 제공하지 못함으로써 개인 학습의 동기부여가 감소됨에 따라 흥미를 잃게 되었다. 본 논문에서는 이러한 문제점을 개선하기 위해 멀티 캐스팅 기법을 통해 교육용 서버를 이용한 학습지원도구를 분석, 설계한다. 가상강의는 기본적인 컨텐츠를 제시하고 그를 통해 수업이 진행되는 과정에서의 질의응답을 일대다(One-To-Many)의 멀티 캐스팅 서비스를 튜터가 지정한 교육용 서버를 통해 텍스트 형식이 아닌 강의자료로 쓰인 문서 파일에 직접 작성하여 전송하게 된다. 따라서 튜터는 메일링 서비스를 통해 질문사항을 자신의 폴더 서비스로 확인하고 즉시 학습자에게 피드백을 제공함으로써 튜터와 학습자들간의 커뮤니케이션이 활발히 이루어지며, 상호작용의 증가를 통해 웹 기반의 컨퍼런싱(WBC: Web Based Conferencing)을 가질 수 있게 된다.rver는 Client가 요청한 Content(services)를 전달 해 주는 컨텐트 전달 모듈(Content Deliver Module)과 서버 Phonebook 엑세스 모들(Server Phonebook Access Module)로 구성되어 있다.외 보다 높았다(I/O ratio 2.5). BTEX의 상대적 함량도 실내가 실외보다 높아 실내에도 발생원이 있음을 암시하고 있다. 자료 분석결과 유치원 실내의 벤젠은 실외로부터 유입되고 있었고, 톨루엔, 에틸벤젠, 크실렌은 실외뿐 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.13-24
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• 2003

MPEG-4 is a standard for multimedia applications and provides a set of technologies to satisfy the needs of authors, service providers and end users alike. In this paper, we suggest a Real-time Multiple Circular Buffer (M4RM Buffer) model, which is suitable for streaming these MPEG-4 contents efficiently. M4RM buffer generates each structure of the buffer, which matches well with each object composing an MPEG-4 content, according to the transferred information, and manipulates multiple read/write operations only by its reference. It divides the decoder buffer and the composition buffer, which are described in the standard, by the unit of frame allocated to minimize the range of access. This buffer unit of a frame is allocated according to the object description. Also, it processes the objects synchronization within the buffer and provides APIs for an efficient buffer management to process the real-time user events. Based on the performance evaluation, we show that M4RM buffer model decreases the waiting time in a buffer frame, and so allows the real-time streaming of an MPEG-4 content using the smaller size of the memory block than IM1-2D and Window Media Player.