• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.67-70
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• 2004

수십, 수백만의 이동 객체가 존재하는 환경에서 전체 이동 객체의 궤적을 중앙 서버가 모두 관리하는 것은 적절한 접근 방법이 아니다. 통신 메시지들이 서버에 집중되기 때문에, 높은 네트워크 대역폭, 처리 능력, 그리고 방대한 저장 공간을 보유한 서버를 필요로 하기 때문이다. 이에 본 논문에서는 중앙 서버없이 각각의 이동 객체들이 자기 자신의 궤적을 관리하는 방식을 통해 앞서의 문제를 해결하려한다. 중앙 서버없이 데이터가 네트워크에 분산되어 있는 경우, 특정 데이터에 효율적으로 접근하기 위해서는 색인이 필요하게 되는데, 본 논문에서는 헤더 객체와 헤더 검색 트리라는 것을 정의하여 IPv6의 모바일 IP를 이용한 P2P방법으로 영역 질의, 최근접 질의, 궤적 질의 처리를 할 수 있는 모델을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1698-1701
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• 2012

음성 인식은 사용자의 음성을 문자로 변환하는 기술로 최근 스마트폰의 사용자 인터페이스로 사용되면서 그 활용도가 높아지고 있다. 기존의 스마트폰용 사전 프로그램은 좁은 자판으로 인하여 입력과정에 오타가 많이 발생하고, 찾고자 하는 단어의 발음은 알고 있지만 철자를 알지 못 하는 경우에 검색할 수 없다. 본 논문에서는 음성 명령을 이용한 스마트폰용 영한사전 앱을 설계 및 구현하였다. 외부 음성 인식 서버를 이용하여 음성 명령을 이해하고 클라이언트에 SQLite를 이용하여 사전 데이터 베이스를 구축한다. 클라이언트는 서버로 사용자 음성을 전달하고, 서버는 음성 정보를 텍스트로 변환하여 클라이언트에게 제공한다[1]. 클라이언트는 서버로부터 전송받은 텍스트를 이용하여 사전 데이터베이스를 검색하고, 그 결과를 사용자에게 보여준다.

• Korea Multimedia Society
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• v.6 no.1
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• pp.45-55
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• 2002

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2313-2316
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• 2002

무선 인터넷 인구의 증가로 인하여 다양한 무선 인터넷 컨텐츠가 필요하다. 온라인 게임의 장점과 핸드폰의 이동성을 접목하여 핸드폰에서 할 수 있는 모바일 게임을 설계 및 구현하였다. 이 게임은 클라이언트-서버 구조를 가지고 있으며 PC 게임과 모바일이 연동하여 게임을 할 수 있는 방식을 사용하고있다. 누구든지 쉽게 장소에 구애받지 않고 게임을 할 수 있고 혼자서도 게임이 가능하다. 이 게임에 사용한 클라이언트-서버 통신 모듈은 게임뿐만 아니라 핸드폰에서 실행 가능한 다양한 Application개발에 활용될 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3B
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• pp.168-174
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• 2007

All of users who connect to mobile game want to play seamless real-time game without any loads on game servers. However, as for existing methods, it is not available to effectively distribute server loads. Therefore, in this paper, we design and implement an uniform variance-based load balancer for distributing loads of game servers for wireless online games by suitable load balancing methods. With this methods, we can deal with dynamically increasing game servers as the information about load balancing of specific period is applied to the administrator.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.9-20
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• 2006

Web Map Service on mobile environment, provided with cost effective mobile GIS contents and user preferred POIs(Points of interests), is strongly required at this moment when mobile and portable Internet is rapidly spreaded on mobile user community as information technology and mobile HW are evolved in its speed, bandwidth and features. As the mobile and portable Internet becomes popular in mobile services, LBS(Location Based Service) is positioned on a mobile client as one of the best information infra services. Recently mobile GIS (Geographic Information System) comes in service to support LBS, but it is constrained and limited on its system configuration and its presentation methodology of a map, and also it depends on its run time environment. In this paper, we made an effort to design and implement a GIS computing platform with server based thin client for mobile WMS(Web Map Service). For its cost effective Platform which could be easily building up POIs and GIS contents, we're not using commercial GIS solution but NGII's (National Geographic Information Institute's) DXF numerical map, and representing the maps, GIS contents and POIs by SVG(Scalable Vector Graphics) recommended by OGC(OpenGis Consortium). We're also adapting de facto standard of XML web service technology such as WSDL, SOAP to provide real time mobile GIS service on PDA as well as mobile terminal by applying a GPS receiver for a user's location information on mobile environment.

• Journal of Digital Convergence
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• v.13 no.3
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• pp.193-199
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• 2015

PUSH technology is a technology that can transfer server information without user's request and it is very useful in various areas along with mobile applications. This paper suggest a suitable application model that can utilizes the PUSH technology and mobile devices by finding a useful area. For this, AdMan, a mobile application which can utilize the PUSH technology and mobile devices has been developed. AdMan is a mobile application that developed once and can be able to run on both Android and iOS based mobile devices, since it was developed by using a tool called m-Bizmaker. AdMan is a customer management and advertisement system that can bring big efficiency by utilizing the PUSH technology and mobile application under the today's mobile environment, and it is a good model of ICT technology application of modern society. As an application that can maximize the utilization of the PUSH technology and mobile devices, AdMan can realize better effectiveness if it run on a PUSH server.

• Journal of Korea Multimedia Society
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• v.15 no.6
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• pp.814-826
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• 2012

In this paper, we propose scheduling algorithms for transporting variable-bit-rate video stream using playback buffer level of the clients over wireless communication networks. The proposed algorithms attempt to maximize the utilization of limited bandwidth between the central video server and the clients over a mobile network. Since a video server may serve several video request at the same time, it is important to allocate and utilize network bandwidth to serve them fairly and efficiently. In order to improve the quality of service and real-time performance of individual video playback, the video server attempts to allocate temporarily more network bandwidth to serve a video request with the lower buffer level preferentially. The simulation results prove the fair service and load balancing among the mobile concurrent clients with different buffer levels and hence maximizing the number of frames that are transported successfully to the client prior to their playback times.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1376-1384
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• 2008

Numerous researches on network self-configuration have been conducted on Wireless Sensor Network (WSN) and Ad Hoc network but the results have not been applied yet for factory automation. This paper presents development of intelligent process management systems conducting process monitoring and control irrelevant to physical position of a plant operator. The systems are indispensable for diagnosis of rotating machines which cannot exploit wired network. The system was implemented in a Personal Digital Assistant (PDA) using Bluetooth communication protocol. When a mobile terminal reaches to communication range of the process management server, the server detects the mobile terminal to reconfigure plant network automatically. The server authenticates a user of the terminal to download and installs monitoring and control program considering authorized level of the user. If the terminal leaves communication range of the server, it deletes the node from the network and removes the program automatically to save resources and prevent security problems such as missing terminal. Operation of developed functions was verified in a testbed emulating steel-making plant.

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.7-14
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• 2022

Unlike general maps, the underground geospatial Information is a system made to view underground information in a 3D shape. This system is managed by a tile maps to lighten the data. But there are various underground structures in the basement, and the structures are made of 3D data, so the data size is large. Therefore, when a client mobile program requests a tile map, the service server fetches the requested tile map from the DB server and transmits ti to the client, but there is a transmission delay time problem. In this paper, we design the tile cache method to improve the request response speed for the tile map data provided to the client in the mobile underground geospatial information system. We propose a method in which a service server predicts and prefetchs the next tile map while the client is viewing tile map, and stores the prefetching data in the memory of client mobile terminal. Then, the transmission delay time problem can be solved.