• Journal of the Korean Society of Systems Engineering
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• v.2 no.2
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• pp.45-50
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• 2006

Tilting technology is to tilt the train on the curve in order to minimize centrifugal force to passengers and to improve the speed within the limits of passenger's comfort and safety. According to reports from other countries, there is 15~30% speed improvement compared to the conventional trains. Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative applications with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. TTX_PDM is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.1
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• pp.50-58
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• 2003

Recently we have built a VR(Virtual Reality) theater in Kyongju, Korea, which combines the advantages of VR and IMAX theater. The VR theater provides a virtual environment for several hundreds of people at the same time. The VR theater can be characterized by a single shared screen and by multiple inputs from several hundreds of people. In this case, multi-user interaction is different from that of networked VR systems and must be reconsidered. This paper defines the multi-user interaction in such a VR theater as Audience Interaction, and discusses key issues for the implementation of the Audience Interaction. This paper also presents a real implementation example in the Kyongju VR theater.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.211-216
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• 2011

Networked virtual environments (NVEs) are distributed systems where geographically dispersed users interact with each other in virtual worlds by exchanging network messages. Massively Multiplayer Online Game (MMOG) is one of diverse applications where more than hundreds of users enjoy experiencing virtual worlds. A limited area called area of interest (AOI) in MMOG is reduced the load caused by message exchange between users. Voronoi-based Overlay Network (VON) is proposed to reduce the bandwidth consumption in P2P environments and Vorocast also is made using message forwarding in VON. We propose a dynamic AOI management method that solves problems such as a consistency and latency due to forwarding position updates to neighbor nodes from the message originator in forwarding scheme. Our scheme provides the consistency and reduces latency by combining direct connection scheme and Vorocast scheme compared to existing schemes. The communication between a user and users existing in center circle within AOI of the user is directly connected and the communication between the user and users existing outside the center area within AOI is using Vorocast scheme. The proposed model is evaluated through simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.714-719
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• 2005

In this paper, the informative space is proposed to implant ubiquitous functions into physical spaces. We merge physical and virtual spaces through the space structurization using an RFID system, and solve the space localization and mapping problem for a robot to navigate through the distribution and synthesis of information and knowledge. To distribute knowledge flexibly and reliably to changing environment and also to develop a system which allows a robot to invoke and merge the distributed knowledge more freely, we employ a novel approach of knowledge management based on Web services. The proposed method is verified by building a physical space with two kinds of RFID tags and a virtual space with knowledge database based on Web services.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.387-388
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• 2016

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.64-69
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• 2007

이 논문은 촉각 가상 환경(Haptic Virtual Environment)에서 촉각(haptic) 데이터를 촉각 데이터 특성에 맞추어 네트워크에 적응적이고 효율적으로 전송할 수 있는 전송 알고리즘을 제안한다. 촉감 상호작용 측정을 위해 네트워크 햅틱 협업 응용을 작성하였고 지연, 지터, 손실에 따른 변화를 분석하였다. 이를 바탕으로 네트워크 트래픽에 적응할 수 있는 알고리즘을 구성하였다. 손실되거나 지터의 영향을 받은 패킷에는 간단한 선형예측 방법을 사용하여 보상하여 손실과 지터로 인한 오차를 줄였다. 이는 심각한 손실이나 지터에 의해 떨림 현상이 나타나는 햅틱 장치의 문제점을 개선하게 되었다. 또한 네트워크 협업에서 지연이 발생할 때 나타나는 클라이언트들 사이의 비동시성을 해결하기 위하여 완충시간을 두었다. 지연이 큰 클라이언트는 버퍼를 사용하지 않고 실시간으로 처리하고, 지연이 적은 클라이언트는 버퍼를 사용하여 전송받은 좌표를 완충시킨 후에 처리하는 방법을 사용하여 클라이언트들 사이의 햅틱 렌더링을 동기화 하였다. 제안된 알고리즘은 다양한 네트워크 상황에서의 협업에서 개선된 결과를 보였다. 이를 바탕으로 향후 선형예측 방법을 다양하게 적용시키고 서버와 클라이언트 사이의 동기화를 구현하는 알고리즘을 작성할 것이다. 본 논문은 다양한 네트워크 상황 에서 햅틱 데이터를 전송하고 처리하는 연구의 기초자료가 될 수 있을 것이다.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.177-180
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• 1999

Nowadays, one of the major technical issues in manufacturing is to create an environment to promote collaboration among diverse engineering activities. Collaborative engineering is an innovative approach integrating widely distributed engineering activities through promoting information sharing and actual collaboration. It requires close interactions among developers, suppliers and customers, and consideration of entire product life cycle from concept to disposal. A carefully-designed operating system is crucial for successful collaboration of many different activities in a Networked Virtual Manufacturing System(NVMS). High extensibility, flexibility and efficiency ale the key characteristics requested of an operating system to handle the complexity of the NVMSs. In this paper, we propose a model of the operating system for collaborative engineering using concurrent quasi-procedural method(QPM). QPM is a goal-driven data management technique for distributed and parallel computing environments. It is to be applied to the evaluation of activities to be executed, validities of input data, execution path of activities for a needed output, and expected to greatly improve the productivity of operations by preventing redundant evaluations. Collaboration among many different engineering activities in NVMSs is to be performed by the network of agents that encapsulate the capabilities of both users and their tools.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.642-652
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• 2001

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. We introduce Virtual Architectural Engineering 2000 (VAE2000) that is our pilot application implemented with the Share collaboration engine. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. VAE2000 is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

• International journal of advanced smart convergence
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• v.5 no.1
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• pp.34-46
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• 2016

Networked Control System (NCS) has evolved in the past decade through the advances in communication technology. The problems involved in NCS are broadly classified into two categories namely network issues due to network and control performance due to system network. The network problems are related to bandwidth allocation, scheduling and network security, and the control problems deal with stability analysis and delay compensation. Various delays with variable length occur due to sharing a common network medium. Though most delays are very less and mostly neglected, the network induced delay is significant. It occurs when sensors, actuators, and controllers exchange data packet across the communication network. Networked induced delay arises from sensor to controller and controller to actuator. This paper presents an adaptive delay compensation process for efficient control. Though Smith predictor has been commonly used as dead time compensators, it is not adaptive to match with the stochastic behavior of network characteristics. Time delay adaptive compensation gives an effective control to solve dead time, and creates a virtual environment using the plant model and computed delay which is used to compensate the effect of delay. This approach is simulated using TrueTime simulator that is a Matlab Simulink based simulator facilitates co-simulation of controller task execution in real-time kernels, network transmissions and continuous plant dynamics for NCS. The simulation result is analyzed, and it is confirmed that this control provides good performance.