• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.343-347
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• 2002

In this paper, we can easily update teaming information by using database built in web server system in implementation of a web courseware that a learner can effectively team the 'Digital Circuits' subject. Also, we offered multimedia elements such as graphics, animations, and voices etc. for increasing understanding and interaction of teaming and designed and implemented a simulation-type web courseware of practice-oriented. In result, it can encourage a learner with a motive of learning and increase effects of teaming. Also, a learner can learn various contents because we can add teaming contents to database according to needs. Furthermore, it can improve understanding for teaming by offering feedback on the result. In future, we need to design and implement circuits with more complex and many functions by adding circuit with function that can store.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.53-56
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• 2001

It has been increasing that the use of Mobile Internet these days. And the demand of user is changing from the text based services to multimedia based data services like pictures, sounds and streaming videos in Mobile Internet. In this paper, It is proposed a remote monitoring system that .an transfer the video data through WAP(Wireless Application protocol) based Mobile Internet used generally in anywhere. And this system is a low-cost efficient system compared with a existing high-cost Internet Camera system, using video module connected to Internet directly and PC-based server. In this paper, It is explained a design and implementation of such WAP-based remote monitoring system.

• ETRI Journal
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• v.42 no.2
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• pp.163-174
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• 2020

Numerous wearable technology companies have recently developed several headmounted display (HMD) products for virtual reality (VR) services. 5G wireless networks aim at providing high-quality 3D multimedia services such as VR, augmented reality, and mixed reality. In this study, we examine the application of millimeter-wave (mmWave) technology to realize low-latency wireless communication between an HMD and its content server. However, the propagation characteristics of mmWave present several challenges such as the deafness, blockage, and beam alignment problems, and interference among content servers. In this study, we focus on an environment that provides VR services in the mmWave band and introduce existing techniques for addressing such challenges. In addition, we employ a commercialized IEEE 802.11ad VR dongle to measure the actual data rate of an mmWave VR application and identify the degree to which the performance deteriorates when the above problems occur. Finally, we verify the feasibility of the proposed solutions through a simulation of several VR scenarios in the mmWave band.

• Journal of the Korea Society of Computer and Information
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• v.21 no.12
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• pp.43-49
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• 2016

This paper presents the design and implementation of virtual aquarium by generating 3D models of fishes that are colored by viewers in an aim to create interaction among viewers and aquarium. The virtual aquarium system is composed of multiple texture extraction modules, a single interface module and a single display module. The texture extraction module recognize the QR code on the canvas to get information of the predefined mapping table and then extract the texture data for the corresponding 3D model. The scanned image is segmented and warp transformed onto the texture image by using the mapping information. The extracted texture is transferred to the interface module to save on the server computer and the interface module sends the fish code and texture information to the display module. The display module generates a fish on the virtual aquarium by using predefined 3D model with the transmitted texture. The fishes on the virtual aquarium have three different swimming methods: self-swimming, autonomous swimming, and leader-following swimming. The three different swimming methods are discussed in this paper. The future study will be the implementation of virtual aquarium based on storytelling to further increase interactions with the viewer.

• Journal of the Korea Society of Computer and Information
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• v.22 no.1
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• pp.15-21
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• 2017

In this paper, we present a solution to the problems caused by using only text - based information as an index element when a commercialized missing person indexing system indexes missing persons registered in the database. The existing system could not be used for the missing persons inquiry because it could not formalize the image of the missing person registered together when registering the missing person. To solve these problems, we propose a method to extract the similarity of images by using OpenCV image processing and TensorFlow deep - running image processing, and to process images of missing persons to process them into meaningful information. In order to verify the indexing method used in this paper, we constructed a Web server that operates to provide the information that is most likely to be needed to users first, using the image provided in the non - regular environment of the same subject as the search element.

• ETRI Journal
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• v.35 no.4
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• pp.687-696
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• 2013

The development of proxy caching is essential in the area of video-on-demand (VoD) to meet users' expectations. VoD requires high bandwidth and creates high traffic due to the nature of media. Many researchers have developed proxy caching models to reduce bandwidth consumption and traffic. Proxy caching keeps part of a media object to meet the viewing expectations of users without delay and provides interactive playback. If the caching is done continuously, the entire cache space will be exhausted at one stage. Hence, the proxy server must apply cache replacement policies to replace existing objects and allocate the cache space for the incoming objects. Researchers have developed many cache replacement policies by considering several parameters, such as recency, access frequency, cost of retrieval, and size of the object. In this paper, the Weighted-Rank Cache replacement Policy (WRCP) is proposed. This policy uses such parameters as access frequency, aging, and mean access gap ratio and such functions as size and cost of retrieval. The WRCP applies our previously developed proxy caching model, Hot-Point Proxy, at four levels of replacement, depending on the cache requirement. Simulation results show that the WRCP outperforms our earlier model, the Dual Cache Replacement Policy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.129-136
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• 2006

We propose a new data carousel scheduling algorithm for on-demand data broadcasting in DMB. The server divides data items into two sets named hot and cold, according to request statistics from clients. When constructing a data carousel, hot items are placed periodically with their upper limit of broadcasting frequency. If there are empty slots after placing hot items, cold items with high request ratio are placed until the carousel is full. A cold item is broadcast only once in the caroulsel. For the response on clients' requests, our proposed scheme is shown to have high success ratio with short waiting time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.195-207
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• 2011

In this paper, we design and implement a visual IMS protocol analyzer, VIPA(Visual IMS Protocol Analyzer), providing a graphical view of session connection information between user equipments on IMS network. The VIPA captures SIP packets, which are used to setup sessions on IMS networks, and shows graphical view of session information to provide easy way to analyze IMS protocols. The existing protocol analyzer has limitation to show only terminal side protocol analysis information. Whereas the VIPA can provide not only terminal side but also server side analysis result so that the connection status between all the session participating user agents can be monitored.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.360-363
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• 2008

현재 통신 시장의 상황은 유무선 통신서비스 시장의 포화, 이동통신 시장의 기존 유선전화 규모 초과, 그리고 유선통신의 서비스 사업자의 영역 확대 도모 등을 특징으로 한다. 유무선 통합 (Fixed Mobile Convergence, FMC) 서비스는 유선통신 사업자를 중심으로 한 비즈니스 모델로 사용자에게 유무선 통신망 종류에 상관없이 일관되고 끊김없는 서비스를 제공하는 것을 목표로 한다. 이동통신망까지 확대하여 고객 기반을 유지하고자 하는 유선사업자들은 FMC 서비스 중 하나의 방안으로 IMS (IP Multimedia Subsystems) 기반의 VCC(Voice Call Continuity) 기능에 주목하고 있다. VCC AS(Application Server)는 이종망 (WiFi-CDMA)간 Seamless 핸드오버기능을 수행하므로, WiFi 와 CDMA를 지원할 수 있는 듀얼단말을 이용하여 사용자가 WiFi 서비스 지역과 CDMA 서비스 지역간 이동시에도 Seamless 한 음성서비스를 제공한다. 이에 본 논문은 IMS/VCC 기반으로 음성 seamless 핸드오버 적용 사례(시범서비스)를 중심으로 유무선 통신사업자 상호 Win-Win을 추구할 수 있는 LG데이콤 특화 VCC 모델을 제시한다. 그리고 LG데이콤이 추구하는 차세대 서비스인 사용자 context 기반의 개인화된 서비스 제공을 위한 IMS 기반 통합 프로파일/인증/과금 연구 동향에 대해 간략히 소개한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.768-776
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• 2002

According as practical use of server system is generalized in multimedia and internet environment, the security of all data that is stored to system is actuality that security mechanism of high level such as competence grant or access control is required. Also, standardization of informations that is stored in system in scattered environment protection technology of more complicated system by absence of done schema, non-systemicity etc. Therefore in this paper. General access control way explained basic modeling because enough investigate and analyze general access control way. And assigning role about each modules separating module of RBAC(Role-Based Access Control) modeling, existent access control modeling and RBAC modeling using mixing new access control modeling present.