• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.446-467
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• 2012

In this paper, the analysis and design of a motion simulator (based on the approach taken by interactive virtual reality (VR) entertainment systems) is conducted. The main components of the system include a bilateral control interface, simulation and a motion simulator control scheme. The space entertainment system uses a virtual environment that enables operators to feel the actual feedback sensing and distorted motion from the virtual environment, just as they would in the real environment. The space entertainment system integrates the dynamics of the motion simulator and the virtual environment and the operator maneuvers a steering wheel to interact with the system. The multiple bilateral control schemes employ a dynamical controller, which is designed by considering the velocity and acceleration that the operator imposes on the joystick, the environmental changes imposed on the motion simulator. In addition, we develop a calculated method to evaluate the Ratio of the simulation results. It is shown that the proposed control scheme can improve the performance of the visual entertainment system. Experiments are conducted on the virtual reality entertainment system to validate the theoretical developments.

• 한국멀티미디어학회논문지
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• 제15권12호
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• pp.1499-1505
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• 2012

Recently, the distributed processing system for big data has been actively investigated owing to the development of high speed network and storage technologies. In addition, virtual system that can provide efficient use of system resources through the consolidation of servers has been increasingly recognized. But, when we configure distributed processing system for big data in virtual machine environments, many problems occur. In this paper, we did an experiment on the optimization of I/O bandwidth according to the creation and placement of VMs and tasks with composing Hadoop cluster in virtual environments and evaluated the results of an experiment. These results conducted by this paper will be used in the study on the development of Hadoop Scheduler supporting I/O bandwidth balancing in virtual environments.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.17-21
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• 2014

This paper presents the effects of the time delay on the stability of the haptic system that includes a virtual wall and a first-order-hold method. The model of a haptic system includes a haptic device model with a mass and a damper, a virtual wall model, a first-order-hold model and a time delay model. In this paper, the time delay is considered as the computational time delay that is assumed to be as much as the sampling time. As the time delay increases, the maximal available stiffness of a virtual wall model is reduced reversely. The relation among the time delay and the maximum available stiffness, the mass and the damper of the haptic device are analyzed using the MATLAB simulation.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.346-351
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• 2007

As the construction technology is rapidly advancing internationally, the necessity of virtual construction technology development is drastically demanded in the construction industry together with a fusion technology with information technology(IT). The construction technology will be changed as the paradigm of construction technology in the future. The establishment of building structural system in the virtual construction basis is necessary for the integration of construction process, and it will be expected to produce the effect of reduction of construction period and quality improvement through the environment of integration. This study is to present the analysis of the existing process of structural design, the content of research & development as per the building structural system on virtual construction basis and the direction of research.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1996년도 춘계학술대회논문집
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• pp.151-151
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• 1996

컴퓨터 기술의 급격한 발전은 현실세계의 각종 현장을 컴퓨터 가상공간 내에서 시험할 수 있도록 하고 있다. 최근들어급격한 발전이 이루어지고 있는 가상현실(Virtual Reality) 기술과 인간의 감성을 중시한 감성공학적 접근방법 론의 활용은 그 적용범위가 점차 확대되어 가고 있는 상황으로, 제조기업에서 사용되고 있는 통합생산 정보시스템 (Computer Integrated Manufacturing)과의 접목으로 가상공장(Virtual Factory) 시스템을 구현할 수가 있다. 가상공장시스 템은 제조기업의 Businiss를 Design & Engineering, Production Planning & Control, Manufacturing의 3가지 프로세스로 분류한다. 그리고 각 프로세스별로 현재의 CIM시스템에 대한 하부시스템을 검토하고, 인간 중심의 가상기업시스템을 구현 하는데 보완이 되어야 할 사항과 이에 대한 해결 대안으로 Design & Engineering Process에서는 Virtual Engineering(VE) Sub-system, Manufacturing Process에서는 Virtual Manufacturing(VM) Sub-system으로 분류하여 각 Sub-system별 구성모듈을 설계하고 상호간의 Interface 사항을 설계하므로서 가상공장시스템 구현을 위한 기본 요구사항과 조건을 제시하고자 한다.

• 한국정보처리학회논문지
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• 제5권10호
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• pp.2627-2640
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• 1998

본 논문은 이동 컴퓨터 통신 환경에서 IP(Internet Protocol) 데이터그램을 전송하기 위한 가상 셀 시스템(virtual cell system0의 성능 분석을 다룬다. 하나의 가상 셀은 이웃한 다수의 물리적 셀(physical cell)들의 집합으로서, 원격브리지(remote bridge)로 구현된 기지국(base station)들을 멀티캐스트 기능을 갖는 고속 데이터그램 패킷 데이터망으로 연결하여 구성된다. 가상 셀 시스템에서의 호스트 이동성은 기지국들 사이에 분산되어 있는 계층적 위치정보를 기반으로 동작하는 데이터링크 계층의 가상 셀 프로토콜(Virtual Cell Protocol )을 통하여 지원된다〔1〕. 이러한 가상 셀 시스템은 물리적 셀들 사이에 임의의 호스트 이동성 패턴과 데이터전송 패턴이 주어진 경우에 전체 시스템의 통신 비용을 최소화할 수 있도록 논리적으로 유연한 가상 셀 시스템의 구축을 가능하게 한다〔2〕. 본 논문에서는 가사 dtpf 시스템의 성능 모델로서 BCMP 개방 복합 클래스 대기 행렬 네트워크(BCMP open multiple class queueing network)를 채택하고, 물리적 셀들 사이의 호스트 이동성 패턴과 데이터전송 패턴에 대하여 임의의 토폴지와 최적화된 토폴로지로 구축된 가상 셀 시스템의 성능을 비교 분석한다. 특히 이동 호스트 수, 이동 속도, 그리고 데이터전송 양과 같은 다양한 시스템 파라메타를 변화시키면서 이에 따라 생성되는 데이터 메시지, 핸드오프(handoff) 메시지, 그리고 주소 용해(address resolution) 메시지 각각에 대하여 망 구성요소의 이용도(utilization)와 시스템 처리 시간(system response time)을 비교 분석한다.

• 한국철도학회논문집
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• 제8권4호
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• pp.330-336
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• 2005

This paper presents a development of the control and the virtual reality visual system for a tilting train simulator. The user of the tilting train simulator is able to set up the environmental and operating conditions through the user interface provided by the control system. In the control system, an arbitrary track which has user-defined curve radius, length and direction can be generated. The virtual reality visual system provides an artificial environment that is composed of several facilities such as station, platform, track, bridge, tunnel and signaling system. In order to maximize the reality, all of the 3D modeling were based on the real photographs taken in the Jungang line. A dome screen with 1600mm diameter was used to maximize the view angle. The hemispherical screen can ensure the view angle of the 170 degrees of vertical direction and 135 degrees of lateral direction.

• 해양환경안전학회지
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• 제6권1호
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• pp.1-9
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• 2000

The paper describes system design of next-generation Ship Simulator using Virtual Reality (VRSS), well known as human-computer interaction. VRSS system is required to have special condition that comprises multiple user participants such as captain, officer, pilot, and quartermaster. To cope with that condition, core technologies were explored and proposed multi-networking system with broker server. The evaluation of the proposed system was done with PC-based immersion-type VR device, constituted with HMD (Head Mounted Display), Head Tracking Sensor, Puck, Headphone, and Microphone. Using the VR device, assessment test was carried out in a virtual bridge with 3D objects, which are created by VRML (Virtual Reality Model Language) program. As results of tests, it is shown that the cybernetic 3D objects were act as if real things in a real ship's bridge. Therefore, interesting interaction with participants can be obtained in the system, Thus, we found that the proposed system architecture can be applicable to VRSS system construction.

• Journal of Power Electronics
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• 제18권5호
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• pp.1555-1566
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• 2018

Proportional capacitor-current-feedback active damping (AD) is a common damping method for the resonance of LCL-type grid-connected inverters. Proportional capacitor-current-feedback AD behaves as a virtual resistor in parallel with the capacitor. However, the existence of delay in the actual control system causes impedance in the virtual resistor. Impedance is manifested as negative resistance when the resonance frequency exceeds one-sixth of the sampling frequency ($f_s/6$). As a result, the damping effect disappears. To extend the system damping region, this study proposes a virtual resistor-inductor-capacitor (RLC) AD method. The method is implemented by feeding the filter capacitor current passing through a band-pass filter, which functions as a virtual RLC in parallel with the filter capacitor to achieve positive resistance in a wide resonance frequency range. A combination of Nyquist theory and system close-loop pole-zero diagrams is used for damping parameter design to obtain optimal damping parameters. An experiment is performed with a 10 kW grid-connected inverter. The effectiveness of the proposed AD method and the system's robustness against grid impedance variation are demonstrated.

• 한국인터넷방송통신학회논문지
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• 제10권4호
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• pp.77-82
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• 2010

본 연구에서는 가상낚시시스템(VFS, Virtual Fishing System)을 위해 제작된 햅틱장치인 FishBot을 개발한다. FishBot는 XY테이블에 휠축을 장착한 3자유도 로봇으로 구성된다. 물고기의 동작을 모사하기 위해 XY 축 제어는 토크값을 가변적으로 제한하는 모션 위치 제어 모드로 하고 휠 축은 힘제어 모드로 하였다. 낚싯대는 실제 낚싯대에 LED를 장착하고 웹 카메라를 튜닝하여 낚싯대의 위치를 인식할 수 있도록 하였다. 결과적으로 제작된 Fishbot은 물고기와 같이 위치와 속도를 변화하고 DAC를 통해 낚는 힘을 제어할 수 있으며 낚싯대 끝단의 위치를 관측하여 가상현실시스템(Virtual Reality System)상에서 연동할 수 있게 하였다.