• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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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.

• Journal of Korea Game Society
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• v.8 no.4
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• pp.29-43
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• 2008

The virtual world is a cyber gaming space where a player interacts with others through their avatars. It is now mainly developed in foreign countries including USA, Canada, and Europe and many experts say that the market capacity of virtual world will be continually expanded in worldwide. The virtual world will mostly be made such that a user accesses the world for free and pays for in-game activities. But it is hardly that we find the effective methodology of payment system for such virtual world due to its' short development history. In the case of Korea, various payment methods of selling in-game assets have been tested in online games. The paper propose an effective revenue model for social virtual world focused on selling in-game assets. The guideline of the proposed revenue model will be expected to contribute creating revenue focused on selling in-game assets, effectively for social virtual world.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.4
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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.

• Journal of Institute of Convergence Technology
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• v.7 no.2
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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.

• Journal of Institute of Convergence Technology
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• v.5 no.2
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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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.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.259-265
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• 2006

Learning and emotions are very important parts to implement intelligent robots. In this paper, we implement intelligent virtual character based on reinforcement learning which interacts with user and have internal emotion model. Virtual character acts autonomously in 3D virtual environment by internal state. And user can learn virtual character specific behaviors by repeated directions. Mouse gesture is used to perceive such directions based on artificial neural network. Emotion-Mood-Personality model is proposed to express emotions. And we examine the change of emotion and learning behaviors when virtual character interact with user.

• Korean Institute of Interior Design Journal
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• v.20 no.5
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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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• v.1 no.1
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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.