• 대한가정학회지
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• 제42권4호
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• pp.99-118
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• 2004

This study examined different individual and environmental factors that affect children's game addiction tendency. As individual variables, game user' motivation, self-control, and self-esteem were included in the analysis. As family variables, communications with mothers, parental control of children's computer use and parental internet use were examined, as school variables, school adjustment and teacher's supervision of children's computer use, and as peer variables, peer group's attitude toward computer games were used. The sample consisted of 994 fifth and sixth grade children. Statistics and methods used for the data analysis were Cronbach's alpha, frequency, percentage, two way ANOVA, Pearson's correlation and Hierarchical Regression. Several major results were found from the analysis. First, boys were addicted more than girls. No difference was found in the addiction tendency between the 5th graders and the 6th graders. Second, game users' motivation, that is, their interest-amusement motive, avoidance motive and aggressive motive, had a positive correlation with their game addiction tendency. However, self-control and self-esteem had a negative correlation with children's game addiction tendency. Third, problematic communications with mothers and parental control of children's computer use had a positive correlation with children's game addiction tendency. Open communications with mothers had a negative correlation with children's game addiction tendency. Fourth, school adjusaent had a negative correlation with children's game addiction tendency. And peer group's attitude towards computer games had a positive correlation with children's game addiction tendency. Fifth, low self-control, peer group's attitude towards computer games, children's interest-amusement motive, avoidance motive, aggressive motive, school lesson adjustment, parental control of children's computer use and school nile adjustment were important predicting variables of boy's game addiction tendency. Avoidance motive, low self-control, interest-amusement motive, peer group's attitude towards computer games, and parental control of children's computer use were important predicting variables of girl's game addiction tendency.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.193-194
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• 2007

In this paper we present work done by Kodak Graphic-Communications-Group and our partners demonstrating applications where laser direct imaging could replace photolithography in display manufacturing. Such applications range from direct manufacturing (e.g. LCD color-filters) to producing “masters” where manufacturing is done by traditional printing methods (e.g. flexography, Gravure-printing).

• 대한수학회논문집
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• 제11권4호
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• pp.933-936
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• 1996

In this paper, we shall prove that the Kim-Kostrikin group is isomorphic to a hyperbolic orbifold group and so it is infinite.

• Communications for Statistical Applications and Methods
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• 제6권1호
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• pp.207-220
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• 1999

In this paper, some of the issue about a group sequential method are considered in the Bayesian context. The continuous time optimal stopping boundary can be used to approximate the optimal stopping boundary for group sequential designs. The exact stopping boundary for group sequential design is obtained by using the backward induction method and is compared with the continuous optimal stopping boundary and the corrected continuous stopping boundary.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권11호
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• pp.2920-2939
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• 2012

Enterprises that develop online games have to deploy supporting infrastructures, including hardware and bandwidth resources, in order to provide a good service to users. First Person Shooter games generate high rates of small UDP packets from the client to the server, so the overhead is significant. This work analyzes a method that saves bandwidth, by the addition of a local agent which queues packets, compresses headers and uses a tunnel to send a number of packets within a multiplexed packet. The behavior of the system has been studied, showing that significant bandwidth savings can be achieved. For certain titles, up to 38% of the bandwidth can be saved for IPv4. This percentage increases to 54% for IPv6, as this protocol has a bigger overhead. The cost of these bandwidth savings is the addition of a new delay, which has an upper bound that can be modified. So there is a tradeoff: the greater the added delays, the greater the bandwidth savings. Significant reductions in the amounts of packets per second generated can also be obtained. Tests have been deployed in an emulated scenario matching an access network, showing that if the number of players is big enough, the added delays can be acceptable in terms of user experience.

• 대한전자공학회논문지TC
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• 제43권8호
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• pp.15-24
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• 2006

본 논문에서는 다수의 소규모 그룹 멀티캐스트 통신을 위해 제안된 XMIP라는 명시적 모바일 멀티캐스트를 설계하고 구현한다. XMIP는 유니캐스트 라우팅 정보에 기초한 명시적 멀티캐스트의 특징을 상속받아 멀티캐스트 상태유지가 필요없는 간단한 멀티캐스트 메커니즘이다. 본 연구에서는 IETF Mobile IP의 각 이동 에이젼트들을 XMIP와의 연동을 고려하여 수정하고 확장한다. 확장 홈에이젼트로 전송된 XMIP 패킷들은 확장 홈에이젼트의 바인딩 테이블을 참조하여 X-in-X이라는 중첩 터널을 통해 확장 지역 에이젼트들로 전송된다. X-in-X 터널링 메커니즘은 Mobile IP 멀티캐스트 트래픽 집중 문제를 효과적으로 해결할 수 있다. 마지막으로 CDMA2000 1X EV-DO 및 무선랜을 포함하는 이종 모바일 네트워크 환경을 기반으로 XMIP 실험망을 구축하고, 소규모 그룹 통신을 위한 다중 사용자 인스턴트 메신저를 개발하여 실험함으로써 제안하는 프로토콜들의 실효성을 검증한다.

• 방송공학회논문지
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• 제10권3호
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• pp.436-450
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• 2005

본 논문은 사진 앨범을 위하여 미디어 리소스(media resource)와 그에 따른 메타데이터(meta-data)를 통합하는 새로운 미디어 응용 형식을 제안한다. 이는 메타데이터를 JPEG과 같은 사진 미디어와 같이 상호 호환적인 데이터로 만듦으로써, 메타데이터의 재 사용성을 높이는 동시에 사용자가 많은 양의 사진을 앨범으로 구성하기 용이하게 하는데 그 목적이 있다. 제안하는 통합 미디어 형식은 최근 MPEG에서 논의되고 있는 멀티미디어 응용 형식인 MAF(Multimedia Application)를 기반으로 한다. 본 논문은 JPEG과 같은 사진 리소스와 사진과 관련된 MPEG-7기반 메타데이터를 통합하는 미디어의 구조를 제안하고, 통합 미디어를 생성 및 해석할 수 있는 부호기(encoder) 및 복호기(decoder)를 개발하여 제안된 통합 미디어의 효용성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.2042-2060
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• 2013

In wireless sensor networks (WSNs), energy efficiency is one of the most essential design considerations, since sensor nodes are resource constrained. Group communication can reduce WSNs communication overhead by sending a message to multiple nodes in one packet. In this paper, in order to simultaneously resolve the transmission security and scalability in WSNs group communications, we propose a hierarchical cluster-based secure and scalable group key management scheme, called HRKT, based on logic key tree and route key tree structure. The HRKT scheme divides the group key into cluster head key and cluster key. The cluster head generates a route key tree according to the route topology of the cluster. This hierarchical key structure facilitates local secure communications taking advantage of the fact that the nodes at a contiguous place usually communicate with each other more frequently. In HRKT scheme, the key updates are confined in a cluster, so the cost of the key updates is reduced efficiently, especially in the case of massive membership changes. The security analysis shows that the HRKT scheme meets the requirements of group communication. In addition, performance simulation results also demonstrate its efficiency in terms of low storage and flexibility when membership changes massively.

• 정보보호학회논문지
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• 제11권4호
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• pp.77-89
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• 2001

통신 기술의 발달로 최근 원격화상회의나 다중 사용자 게임 등 그룹 중심의 응용이나 서비스가 증가하고 있다. 그러한 정보에 대한 접근제어의 수단으로서 그룹 구성원들이 하나의 그룹키를 공유하여 비밀통신을 하는데, 규모가 크고 동적인 그룹인 경우에는 효율적인 그룹키 갱신 방법이 매우 중요하다. 본 논문에서는 구성원의 가입 및 탈퇴시 발생하는 키갱신의 효율성을 높이기 위하여 높이 균형 트리인 (2,4)-트리를 이용하여 키-트리를 구성하였다. 특히, CBT (Core Based Tree)를 이용하여 네트웍 구성 정보를 유지하도록 하고 이를 키-트리 구성에 반영하도록 함으로써, 네트웍 장애 및 복구로 발생하는 일부 그룹의 분할과 병합 시에도 효율적으로 키갱신을 수행할 수 있는 방안을 제시하였다.

• Journal of Communications and Networks
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• 제11권1호
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• pp.36-41
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• 2009

The IEEE 802.16 wireless metropolitan area network (WMAN) standard is designed to correct expensive communication costs in CDMA-based mobile communication systems and limited coverage problems in wireless LAN systems. Thus, the IEEE 802.16e standard can provide mobile high-speed packet access between mobile stations and the Internet service provider through the base station with cheap communication fees. To efficiently accommodate voice over IP (VoIP) services in IEEE 802.16 systems, an uplink quality of service packet-scheduling scheme is proposed, and its performance is evaluated with an NS-2 network simulator in this paper. Numerical results show that this proposed scheme can increase the system capacity by 100% more than in the unsolicited rand service (UGS) scheme and 30% more than the extended real-time polling service (ertPS) scheme, respectively.