• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.405-412
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• 2006

In this paper, we present an efficient method for simulating massively virtual clients in an online game environment. Massively multi-player online games and other multi-user based networked applications are becoming more attractive to the gamer players. Such kind of technology has long been researched in the area called Networked Virtual Environments. In the game development process, a set of beta tests is used to ensure the stability of online game servers. A set of testing processes consumesa lot of development resources such as cost, time, and etc. The purpose of VENUS system is to provide an automated beta test environment to the game developers to efficiently test the online games to reduce development resources.

• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.118-129
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• 2001

This paper investigates the previous research results on communication and server technologies for networked virtual environments and presents several new technologies to improve performance. Specially, a hierarchical client-server network topology to support numerous clients are presented and a dead-reckoning algorithm considering network latency to provide clients with fair service is also presented. Finally, several examples to confirm the proposed technologies are introduced.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.71-78
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• 2009

One of main concepts involved in regional small nuclear reactors is unmanned remote control. Internet-based virtual private networks provide environments for the remote monitoring and control of geographically-dispersed systems, and with the advances in communication technologies, the potential of networks for real time control and automation becomes enormous. However, networked control has some problems. The most critical is delay in signal transmission, which degrades system stability and performance. Therefore, a networked control system should be designed to account for delay. This paper proposes some design approaches for a delay-tolerant system that can guarantee predetermined stability margins and performance. To accomplish this, the reactor plant is modeled with consideration of uncertainties. With this model, three kinds of controllers are developed using different methods. The designed systems are compared with respect to stability and performance, and a second-order controller designed using the table lookup method was found to give the most satisfactory results.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.29-36
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• 1996

This paper presents animation techniques and issues involved in virtual environments where the participants interact with each other through a network. The state of the participant should be collected at each local site, and broadcasted to the other sites. Because information exchange is minimal, animation techniques are applied to convert the incoming low DOF parameters into high DOF joint angles that completely determine the configuration of the agents at each frame. As a case study, a software system VRLOCO is introduced, which has been developed by the author over the last five years.

• ETRI Journal
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• v.21 no.1
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• pp.55-71
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• 1999

Recently, the increased handling of on-line standards information has emerged as an important feature of information and communications technology (ICT) standardization. In order to meet market needs for on-time standards deployment, most standards organizations are actively seeking more efficient ways of standardization using electronic means in order to accelerate the standards making process. This paper suggests a virtual standard development environment designed for standards developers to carry out their standards-related activities on-line. In this paper, we outline a conceptual model of a concurrent standardization process and describe the design and implementation of an Extranet-based network system called standards information cooperative network (SICN). The system was created with a view to fostering faster standards development with functionalities such as a virtual management of networked standards developers, collaboration support tools, a workflow-based electronic signature system, and dynamic links for ready retrieval of standards information stored in a database. We conclude this paper with an introduction to the concept of a virtual standards development organization (VSDO) that supports all the features needed by the relevant standards making bodies to carry out their activities in a dynamic on-line environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.69-73
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• 2009

Network Virtual Environments (NVEs) is a virtual world where users exchanges messages via network connection. A limited visibility sphere called area of interest (AOI) is used to reduce the load created by the interactions between users. VON-Forwarding model is proposed as an effective methods to reduce network bandwidth in P2P network environment. Vorocast and Fibocast originated from Von-forwarding resolves the problems to receive the same messages repeatly. In this paper, We proposed an Extended Volocast scheme to improve the problem not to get consistency except a limited area near to the center of AOI. The proposed scheme maintains the consistency about the broad area into AOI by adjusting geometrical series $2^X$. We perform simulation experiments to show that the proposed scheme provide better performance compared to the other schemes.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.281-283
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• 2000

분산 가상 환경(DVE)의 사용자 수가 증대됨에 따라, 고려해야 할 사항 중 가장 중요한 것들 중 하나는 상호작용의 성능을 위한 확장성에 있다. DVE의 확장성을 지원하기 위한 방법들 중 하나는 사용자 인지도 관리 기법이다. 기존의 인지도 관리 기법은 사용자의 인지도를 일정한 공간으로 제한을 함으로써 사용자가 받는 메시지의 수를 줄이는 방법이다. 하지만 많은 사용자들이 근접한 곳에 운집한 경우, 사용자는 그 근접한 공간에서 발생하는 모든 메시지를 받아야 한다. 이것은 사용자들에게 통신에 따른 많은 부하가 걸리게 되며 따라서 시스템은 확장성이 떨어지게 된다. 본 연구에서는 각 사용자의 인지도 영역에 사용자가 관심 있는 사물의 타입을 표현하고 같은 관심을 가지고 있는 사용자들끼리 그룹을 생성하여 사용자의 관심도에 따른 선택적인 메시지를 받게 한다. 이를 통하여 각 사용자는 자신과 근접한 공간에 있는 모든 사용자로부터 생성되는 모든 메시지를 받지 않아도 된다. 본 연구를 통하여 확장성 있는 방법으로 사용자간의 상호 작용을 지원할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.163-165
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• 2002

실시간으로 상호 작용하는 어플리케이션에서 성능을 유지하면서 모든 참가자들에게 동일한 뷰를 보여주는 것이 중요하다. 동일한 뷰를 제공하기 위해 사용하는 기법 중 하나로, 참가자들은 받은 이벤트를 실행 시각까지 버퍼에 저장하고 모든 참가자들이 동시에 이벤트를 실행한다. 그러나 네트웍상에서 전송 지연 시간 때문에 실행 예정 시각이 지나서 수신된 이벤트 들은 손실된 이벤트로 처리되어 참가자들 간의 일치하지 않는 뷰를 초래하며 손실된 이벤트를 복구하기 위한 오버헤드가 추가적으로 필요하게 된다. 본 논문에서 제안한 동기화기법은 네트웍 트래픽 상태에 따라 재생 지연 시간을 동적으로 정함으로써 네트웍 트래픽이 감소하여 전송 지연 시간이 짧을 경우, 작은 재생 지연 시간을 적용하여 상호 작용 성능을 높여주고 네트웍상에 트래픽이 증가하는 경우에는 재생 지연 시간을 늘림으로 상호 작용 성능을 해치지 않는 범위에서 이벤트 손실율을 줄이고자 한다. 실험을 통해 이 기법이 효과적으로 작동하는지 알아본다.

• Journal of Korea Game Society
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• v.5 no.4
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• pp.33-38
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• 2005

In the online game that thousands of participants connect to a game world by using Internet simultaneously, participants of the game world may have different hardwares and network environments, and messages of participants should be synchronization. A solution for the synchronization problem is to wait for a certain amount of time until the server processes the message. It is not easy to determine a suitable waiting period because of the trade-off between the fairness and the responsiveness. In this paper we propose a method to decide a waiting period by considering features of the MMOFPS game and the probability of interaction among participants. We implement the proposed method and perform experiments for the performance evaluation.