• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.67-73
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• 2011

With the rapid growth of recent smart phone technology, the interests for the design of online game in mobile computing environment are highly focussed on with great attention. Smart phone as a mobile terminal device, however, has many restrictions for implementing online mobile game since the limitation of relatively low performance of a processor, low resolution of GUI, small memory spaces, and short battery power. Therefore, most of games are very restricted on online and multi-play functions. In this paper, we design and implement mobile online game app in component based smart phone environment in order to take over these restrictions in mobile environment. Especially, the implemented mobile game is able to play online game among Wi-Fi based game server and another smart phone.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.248-260
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• 2009

To connect a mobile ad hoc network (MANET) with an IP network and to carryout communication, ad hoc network node needs to be configured with unique IP adress. Dynamic host configuration protocol (DHCP) server autoconfigure nodes in wired networks. However, this cannot be applied to ad hoc network without introducing some changes in auto configuration mechanism, due to intrinsic properties (i.e., multi-hop, dynamic, and distributed nature) of the network. In this paper, we propose a scalable autoconfiguration scheme for MANETs with hierarchical topology consisting of leader and member nodes, by considering the global Internet connectivity with minimum overhead. In our proposed scheme, a joining node selects one of the pre-configured nodes for its duplicate address detection (DAD) operation. We reduce overhead and make our scheme scalable by eliminating the broadcast of DAD messages in the network. We also propose the group leader election algorithm, which takes into account the resources, density, and position information of a node to select a new leader. Our simulation results show that our proposed scheme is effective to reduce the overhead and is scalable. Also, it is shown that the proposed scheme provides an efficient method to heal the network after partitioning and merging by enhancing the role of bordering nodes in the group.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.27-30
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• 2002

Recently, there are lots of concerning on the control of multi-agent control system and mixed reality integrating real and virtual environments. In this paper, an integrated agent control system based on mixed reality and mobile environment is proposed. The system consists of a manager, agents, a mapping module, a geographic information module, a WAP server, and a mobile manager. The manager has Hybrid Device Manager(HDM) working for revising images and position data of the agents to display that at the 3D virtual and mobile environments respectively. Especially, the images of the agent is translated to LBM format and displayed on the mobile phone, and the current position of the agent is displayed on the display screen, so that a user are able to control the agent when he is moving. Experimental results shows the proposed system lets us control the agents conveniently at a computer and a mobile phone.

• Journal of Broadcast Engineering
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• v.6 no.3
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• pp.225-233
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• 2001

Real-time video communication applications over Internet should be able to support such functionality as scalability because of the unpredictable and varying channel bandwidth between server and client. To accommodatethe wide variety of channel bitrates, a new scalable coding tool, namely the Fine Granular Scalability (FGS) coding tool has been reduce the adopted In the MPEG-4 video standard. This paper presentsa new FGS algorithm with matching Pursuit that can reduce the computational complexity of ordinal matching pursuit-based algorithm. The Proposed coding algorithm can make trade-off between Picture Quality and computationalcomplexity. Our simulation result shows that the proposed algorithm can reduce the computational cumplexity up to 1/5 compared to the conventional FGS method while retaining a similar picture quality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.80-83
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• 2010

As the recent development of mobile technology, users want to multi-service in anytime, anywhere, any terminal. To meet the needs of users, it causes a lot of expense that redesign of the entire network or expand the network of services areas. Therefore, IEEE, IETF is offering Handover technology between Heterogeneous Network. In this paper, the IEEE 802.21 MIH Information Server is based on the network. It proposes an improved Handover that L3 layer to optimize the Handover process use of FMIPv6 and executes simulation.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.731-751
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• 2017

The burgeoning distribution of smartphone web applications based on various mobile environments is increasingly focusing on the performance of mobile applications implemented by JavaScript and HTML5 (Hyper Text Markup Language 5). If application software has a simple functional processing structure, then the problem is benign. However, browser loads are becoming more burdensome as the amount of JavaScript processing continues to increase. Processing time and capacity of the JavaScript in current mobile browsers are limited. As a solution, the Web Worker is designed to implement multi-threading. However, it cannot guarantee the computing ability as a native application on mobile devices, and is not sufficient to improve processing speed. The method proposed in this research overcomes the limitation of resources as a mobile client and guarantees performance by native application software by providing high computing service. It shifts the JavaScript process of a mobile device on to a cloud-based computer server. A performance evaluation experiment revealed the proposed algorithm to be up to 6 times faster in computing speed compared to the existing mobile browser's JavaScript process, and 3 to 6 times faster than Web Worker. In addition, memory usage was also less than the existing technology.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.333-335
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• 2014

스마트폰의 보급에 따라 사용자간에 공유되는 정보가 점점 늘어나고 있다. 시간표 관리 시스템의 경우 과거에는 개별 사용자의 시간표를 관리하는 것이 주요 기능이었으나, 사용자간의 시간표를 비교함으로써 공통으로 가능한 비어있는 시간을 찾는 등 공유 기능에 대한 필요성이 증대되고 있다. 본 논문에서는 이화여대 학생들에게 특화된 편의성과 공유기능을 제공하는 시간표 관리 어플리케이션과 서버 프로그램을 설계하고 개발한다. 제공되는 편의성으로는 사용자가 자신의 시간표를 직접 입력하는 것이 아니라 이화 포탈(eportal.ewha.ac.kr)에서 내 시간표 정보를 자동으로 바로 받아 볼 수 있는 기능과 관련 교과목의 담당교수와 강의실 등의 추가적인 정보가 같이 저장되도록 하여 시간표 작성 시간이 획기적으로 줄일 수 있도록 한다. 또한 모든 사용자가 계정을 등록하여 타 사용자와 함께 듣는 수업과 공강 시간을 자동으로 계산해서 보여주는 공유 기능을 제공한다. 사용자 피드백을 통한 본 논문에서 개발된 시스템을 평가한 결과 편의성과 공유 기능에 만족함을 확인하였다.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.11
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• pp.61-68
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• 2004

Recently, there has been an increasing demand for computer-vision based inspection and/or measurement system as a part of factory automation equipment. Existing manual inspection method can inspect only specific samples and has low measuring accuracy as well as it increases working time. Thus, in order to improve the objectivity and reproducibility, computer-aided analysis method is needed. In this paper, front and side profile inspection and/or data transfer system are developed using computer-vision during the inspection process on three kinds of pipes coming from a forming line. Straight line and circle are extracted from profiles obtained from vision using Laplace operator. To reduce inspection time, Hough Transform is used with clustering method for straight line detection and the center points and diameters of inner and outer circle are found to determine eccentricity and whether good or bad. Also, an inspection system has been built that each pipe's data and images of good/bad test are stored as files and transferred to the server so that the center can manage them.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.577-580
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• 2001

최근 정보통신 기술 발전 및 초고속 통신망의 발달로 인한 인터넷 망(network)상에서의 방송과 통신이 융합되는 추세가 가속화되고 있다. 이에 스트리밍(Streaming) 기술을 기반으로 한 멀티미디어 데이터의 서비스와 데이터 정보의 푸시(push) 기술을 결합하여 인터넷과 고속망상에서의 원활한 실시간 전송 서비스를 위하여 다중 서버를 지원하는 3-tier 방식의 스트리밍 시스템을 구현하였다. 구현된 시스템은 실시간 전송 프로토콜인 RTP(Real-time Transport Protocol)를 이용하여 송신자에게 멀티미디어 스트리밍 서비스를 제공하며, VOD(Video on Demand) 및 실시간 방송 서비스를 제공하는 분산 멀티미디어 스트리밍 전송 시스템이다. 전체 시스템은 인터넷 방송 서비스 제공을 위한 VOD 서버, 실시간 방송 서버 및 푸시 서버와 멀티미디어의 실시간 재생을 위한 클라이언트 인터페이스 등으로 구성되어 있으며, 안정적인 서비스를 위한 미들웨어에서의 부하분배 및 채널 정보의 관리를 가능하게 하였다.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.260-264
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• 2009

There have been many studies on u-Healthcare system for human using sensor network systems. In this paper, we design and implement a healthcare system for pets called uPetCare(Ubiquitous Pet-Care System) that can manage the status of pet on the web. The main functions of this system are 1) gathering data using sensor network, 2) multi-hop communication in sensor network, 3) data compression and aggregation at sink node, 4) storing data in web server, 5) real-time data monitoring using AJAX, 6) activity recognition of pet.