• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.369-380
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• 2003

With the proliferation of a wireless support and the advances of mobile devices, there is a growing need of making it available for a wireless network as well. Low bandwidth of a wireless network is one of the major issues that should be considered for extending a synchronous collaboration system developed for a wired network to supuort a wireless network. We propose a priority-based view synchronization scheme, exploiting the relaxed synchronization. The proposed scheme leverages the fact that mobile users need not have the exactly same view as the users in a wired network since they usually have a limited screen size and thus focus only on part of a whole document. We evaluate the performance of a simple group editor with the propose scheme using ns -2. The performance results show that the proposed scheme keeps the message transmission delay low so that mobile users can have synchronous colloboration with wired users without signification delay. The proposed scheme is designed and implemented as a framework to support various kinds of realtime groupware applications, exploiting the existing groupware framework, Habanero. As a client program, we implemented a simple group text editor.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.5-8
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• 2017

본 논문은 무선 인지 네트워크에서 에너지 하베스팅을 하는 다수의 단말이 하나의 중계기를 사용하여 양방향 통신을 하는 시스템을 다룬다. 한 신호 전송 프레임은 에너지 하베스팅 단계와 신호 전송 단계로 이루어 진다. 에너지 하베스팅 단계에서 각 단말은 일차 사용자의 송신기에서 보내는 무선 에너지 신호를 이용하여 신호 전송에 필요한 에너지를 저장한다. 신호 전송 단계에서 중계기는 처리량이 가장 높은 하나의 유저 쌍을 선택하며, 선택된 유저는 중계기를 통하여 세 단계를 거쳐 정보를 교환한다. 이 때 각 단말에서의 불능 확률을 1) 중계기에서의 전송 전력이 변화할 때, 2) 단말 수가 변화할 때로 나누어 시뮬레이션 하고, 결과를 분석한다.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.589-596
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• 2005

The objective of this paper lies in the design and implementation of a home gateway supporting live video streaming which flows from the Non-SIP video camera in home to the mobile SIP device outside. We developed the home gateway on the OSGi framework and employed the RTC technology which embeds an SIP stack so that the multimedia session can be established from the home device to the mobile user outside. And also we developed an RTC bundle to manage the session and a virtual capture device driver to read the video stream from the Non-SIP video camera in the home network, and installed them on the home gateway. Finally, we constructed the experimental environment that has the windows messenger as the SIP mobile device and an AXIS 2100 UPnP video camera as a video source, and then tested if the session establishment to the mobile user from the camera and live video streaming work well between them.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.658-669
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• 2015

The paradigm of game development changes with technological trends. If the system can analyze and determine undefined inputs, users' input choices are not restricted. Therefore, game scenarios can have multifarious flows depending upon the user's input data. In this paper, we propose a method of including an output plan in the game system that is based on the user's input but is not restricted to predefined choices. We have implemented an experimental game on the Android platform by combining network communication and APIs. The game interface works as follows: first, the user's input data is transmitted to the server using HTTP protocol; then, the server carries out an analysis on the input data; and finally, the server returns the decision result to the game device. The game can provide users a scenario that corresponds to the decision results. In this paper, we used an image file for the user's input data format. The server calculates similarities between the user's image file and reference images obtained from the Naver Image Search API and then returns determination results. We have confirmed the value of integrating the game development framework with other computing technologies demonstrating the potential of the proposed methods for application to various future game interfaces.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1142-1151
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• 2005

Various kinds of studies for building up U-Korea are now underway. Especially, RFID comes into the spotlight as a core technology of Ubiquitous. Though, the development of higher levels of application is far behind the hardware-based technology in RFID application system. For that reason, In this paper suggests technology using RFID on Ubiquitous and embodies the effective health care application which is one of the application services of user-centered environment It realizes the system which enables us to manage and send data about changing prescriptions and locations of patients effectively under the basis of RFID tag and mobile devices. It also provides the high quality of practical effectiveness of entire system throughout the realization of applications of application server and mobile device. on the basis of framework for providing the various kinds of services and physical elements.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.1 no.2
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• pp.70-81
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• 2002

1990년대 후반부터 다양한 디지털 통신망을 이용하여 멀티미디어 컨텐츠 서비스가 가능하게 되었다. 하지만 멀티미디어 컨텐츠의 전달 및 이용을 위한 기반 구조들의 독자적 발전 및 다양한 통합 관리 시스템 때문에 멀티미디어 컨텐츠 표현 방식의 호환성, 네트워크 방식과 단말기 등의 잠재적인 문제점이 발생한다. 이를 위해서 현재 존재하는 기술 및 기반 구조들 사이의 연동을 통한 큰 멀티미디어 프레임워크인 MPEG-21이 진행 중이다. 본 논문에서는 현재 표준화 작업이 진행 중인 MPEG-21을 기반으로 하는 웹 (Web) 기반 테스트베드를 제안한다. 기본적으로 테스트베드는 서버(server), 클라이언트(client), DIA(Digital Item Adaptation)의 세 모듈로 구성된다. 서버의 역할은 멀티미디어 컨텐츠를 Digital Item(DI)의 형태로 생성하고, 클라이언트가 DI를 요구할 경우 DIA 모듈을 통해서 변환된 DI를 클라이언트에게 제공한다. DIA 모듈은 서버에서 동작되며 클라이언트로부터 요청된 DI를 분석하고 클라이언트로부터 전송된 환경 정보를 이용하여 클라이언트 환경에 적합하게 변환된 (adapted) DI를 생성하는 것이 주 기능이다. 클라이언트는 서버에 저장되어 있는 DI를 선택하고 사용자 선호도(user preferences), 터미널 능력(terminal capabilities) 등의 필요한 정보를 서버로 전송한다. 테스트베드에서는 스포츠 경기의 동영상, 정지 영상, 경기 내용, 역사를 기록한 파일 등의 DI를 이용한다. 표현 언어는 XML이며, HTTP 기반의 웹 환경에서 구동되도록 설계된다.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.245-251
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• 2015

If a digital signage system is operated in PC mounted in the Window OS then the implementing price is very high. For resolving this problem, we used the Smartphone mounted in ARM Cortex family of multi-core processor-based mobile platform. We developed a low-power low-cost digital signage system and a remote convergence content management program based on web server. This convergence system manages advertising content to a remote control device anywhere using remote control technology. This system is one integrated system with display and is a low-power consumed and is developed in very efficient hardware interface. And condition sensors(intensity of illumination, temperature, weather, GPS etc) is equipped in the developed system. Automatic contents builder and Context-aware SMIL module is also implemented in the convergence system. We achieved over 50% power savings comparing with conventional Window OS system and 16 points multi-touch in our system.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.104-113
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• 2012

Followed by that HTML5(Hypertext Markup Language5) was introduced, many kinds of program and services based on this have been developed and released. HTML5 is technical standard specifications for cross platform for personal computers and mobile devices so that it is expected that continuing progress and wide application in the both sides of the academic and the industrial fields increase. This study is to design and implement a mobile application program for overlay rendering with DEM and other geo-based image sets using HTML5 WebGL for 3D graphic processing on web environment. Particularly, the blending technique was used for overlay processing with multiple images. Among available WebGL frameworks, CubicVR.js was adopted, and various blending techniques were provided in the user interface for general users. For the actual application in the study area around the Sejong city, serveral types of geo-based data sets were used and processed: KOMPSAT-2 images, ALOS PALSAR SAR images, and grid data by environment measurements. While, DEM for 3D viewing with these geo-based images was produced using contour information of the digital map sets. This work demonstrates possibilities that new types of contents and service system using geo-based images can be extracted and applied.