• 제어로봇시스템학회논문지
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• 제9권8호
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• pp.610-615
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• 2003

This paper proposes a nonlinear virtual coupling fur haptic interface, which offers better performance while maintaining stability of the system. The nonlinear virtual coupling is designed based on a human response model. This human response model exploits delay between the human Intention and the actual change of arm impedance. The proposed approach provides with less conservative constraints for the design of stable haptic interface, compared with the traditional passivity condition. This allows increased performance that is verified through experiments.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.156-159
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• 2008

This paper introduces a remained tensile force estimation method using SI technique based on evolutionary algorithm for externally prestressed tendon. This paper applies the differential evolutionary scheme to SI technique. A virtual model test using ABAQUS 3 dimensional frame model has been made for this work The virtual model is added to the tensile force(28.5kN). Two set of frequencies are extracted respectively from the virtual test and the self-coding FEM 2 dimension model. The estimating tendon tension for the FEM model is 28.31kN. It is that the error in the tendon tension is 1% through the differential evolutionary algorithm. The errors between virtual model and the self-coding FEM model are assumed as the model error.

• 한국게임학회 논문지
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• 제8권4호
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• pp.29-43
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• 2008

가상 세계(Virtual World)는 다수의 플레이어들이 자신을 표현하는 아바타를 통해 한 공간에서 다양한 상호작용을 경험하는 사이버 게임 공간이다. 외국을 중심으로 활발하게 개발 중인 가상 세계는 전 세계적으로 앞으로도 지속적으로 성장할 것으로 기대 된다. 이러한 가상 세계는 가입자들이 가상공간을 무료로 접근하고 가상공간에서의 활동에 대해 과금을 하는 방식이 보편화될 것으로 예상된다. 그러나 대부분의 가상 세계가 2000년 초부터 서비스가 시작되어 가상 세계의 수익 모델에 관한 연구는 초기 단계에 불과하다. 한국의 경우 게임을 무료로 즐기면서 게임 내 아이템 판매 등을 통해 수익을 창출하는 방식에 대한 수많은 시도가 진행되고 있다. 본 논문에서는 한국 온라인 게임의 수익 모델과 외국에서 상업적으로 성공을 거둔 가상 세계의 수익 모델을 분석하여 게임 내 자산 판매 방식을 중심으로 생활형 가상 세계를 위한 효과적인 수익 모델을 제안한다. 이 논문에서 제안하는 게임 내 자산 판매를 통한 수익 모델의 가이드라인은 생활형 가상 세계의 효과적인 수익 창출에 기여할 것으로 예상된다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권4호
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• pp.302-309
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• 2005

We have studied a model and application that evolves the behavioral knowledge of a virtual robot. The knowledge is represented in classification rules and a neural network, and is learned by a genetic algorithm. The model consists of a virtual robot with behavior knowledge, an environment that it moves in, and an evolution performer that includes a genetic algorithm. We have also applied our model to an environment where the robots gather food into a nest. When comparing our model with the conventional method on various test cases, our model showed superior overall learning.

• 융복합기술연구소 논문집
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• 제7권2호
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• pp.25-30
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• 2017

This paper presents the effects of a virtual mass with a low-pass filter on the stability boundary of a virtual spring in the haptic system. In general, a haptic system consists of a haptic device, a sampler, a virtual impedance model and zero-order-hold. The virtual impedance is modeled as a virtual spring and a virtual mass. However the high-frequency noise due to the sampling time and the quantization error of sampled data may be generated when an acceleration is measured to compute the inertia force of the virtual mass. So a low-pass filter is needed to prevent the unstable behavior due to the high-frequency noise. A finite impulse response (FIR) filter is added to the measurement process of the acceleration and the effects on the haptic stability are simulated. According to the virtual mass with the FIR filter and the sampling time, the stability boundary of the virtual spring is analyzed through the simulation. The maximum available stiffness to guarantee the stable behavior is reduced, but simulation results still show that the stability boundary of the haptic system with the virtual mass is larger than that of the haptic system without the virtual mass.

• 융복합기술연구소 논문집
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• 제5권2호
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• pp.37-42
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• 2015

This paper presents the effects of the computational time-varying 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 computational time-varying delay model. In this paper, the maximum of the computational time-varying delay is assumed to be as much as the sampling time. Using the simulation, it is analyzed how the sample-hold methods and the computational time-varying delay affect the maximum available stiffness. As the maximum of computational time-varying delay increases, the maximal available stiffness of a virtual wall model is reduced.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.31-39
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• 2013

A virtual chassis platform for Fuel Cell Hybrid Electric Vehicles(FCHEV) has been developed, and a virtual platform similar to the actual system has been composed. In addition, major components such as a motor, fuel cell and battery for the virtual platform have been constructed by using a mathematical formulation. The FCHEV virtual platform using a detailed model based on the mathematical formula is capable of simulating various conditions according to changes of the control logic and component modules to evaluate performance, considering the vehicle dynamic characteristics. Usability of the mathematical model has been verified by comparative simulations according to the motor current control variation. In addition, reliability of the developed virtual chassis platform has been verified by simulating its fuel consumption with the UDDS(Urban Dynamometer Driving Schedule) FTP-72 velocity profile.

• 한국지능시스템학회논문지
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• 제16권3호
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• pp.259-265
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• 2006

학습과 감정은 지능형 시스템을 구현하는데 있어 가장 중요한 요소이다. 본 논문에서는 강화학습을 이용하여 사용자와 상호작용을 하면서 학습을 수행하고 내부적인 감정모델을 가지고 있는 지능적인 가상 캐릭터를 구현하였다. 가상 캐릭터는 여러 가지 사물들로 이루어진 3D의 가상 환경 내에서 내부상태에 의해 자율적으로 동작하며, 또한 사용자는 가상 캐릭터에게 반복적인 명령을 통해 원하는 행동을 학습시킬 수 있다. 이러한 명령은 인공신경망을 사용하여 마우스의 제스처를 인식하여 수행할 수 있고 감정의 표현을 위해 Emotion-Mood-Personality 모델을 새로 제안하였다. 그리고 실험을 통해 사용자와 상호작용을 통한 감정의 변화를 살펴보았고 가상 캐릭터의 훈련에 따른 학습이 올바르게 수행되는 것을 확인하였다.

• 한국실내디자인학회논문집
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• 제20권5호
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• pp.160-169
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• 2011

In Korea, the construction company has provided houses through apartment sales system. Residents have obtained a variety of information about their future house by visiting a sample house called "the model house" before they purchase home. Advanced technology such as web-based VOD or Virtual Model in recent years has gradually replaced those built environment. In 2009, the Ministry of Land, Transport and Maritime Affairs announced the restraint to the construction of sample houses. Instead, they highly recommended a Virtual Model House as an alternative solution. This study aimed to propose how to design the user-oriented virtual model house through the experiment and survey research. The 3D virtual model house of 85m$^2$ apartment was built and presented by two types (Type A: Bird's Eye View, Type B: Walk through View) on the web page. The subjects evaluated presence, spatial perception and cognition, and usability of each type after exploring them. The results are as follows. (1) The subjects' evaluation of presence showed Type B has more negative effects than Type A such as feeling dizzy or tired even if their values were not so high. (2) The subjects perceived and cognized both types of virtual model house more realistic for the expression of volume of space, the size of opening, and the arrangement of furniture than that of wall finishes and materials. (3) The usability of Type A was significantly higher than that of Type B.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.84-90
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• 2000

The importance of Virtual Manufacturing System is increasing in the area of developing new manufacturing processes, implementing automated workcells, designing plant facility layouts and workplace ergonomics. Virtual manufacturing system is a computer system that can generate the same information about manufacturing system structure, states, and behaviors as is observed in a real manufacturing. In this research, a virtual manufacturing system for flexible manufacturing cells (VFMC), (which is a useful tool for building Computer Integrated Manufacturing (CIM), has been developed using object-oriented paradigm, and implemented with software QUEST/IGRIP. Three object models used in the system are the product model, the facility model, and the process model. The concrete behaviors of a flexible manufacturing cell are re[presented by the task-oriented description diagram, TIC. An example simulation is executed to evaluate applicability of the developed models, and to prove the potential value of virtual manufacturing paradigm.