• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.86-92
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• 1996

Multimedia services through a network are getting more required according to the realization of B-ISDN construction globally. Business using the Internet will become popular, and so multimedia information systems including telemarketing systems will be developed competitively. VR (Virtual Reality) will help such systems make more realistic and valuable. ln this paper, we present an interactive VR authoring tool and a client/server based multimedia information service system. The VR authoring tool serves an interface with the system when developing its applications.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.93-100
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• 2003

This paper describes the thermoelastic instability arising from friction heat generation in braking and proposes the finite element methods to predict the variation of temperature and thermal deformation. In a conventional disc brake analysis, heat generation is only related with wheel speed and friction material and the interface pressure between disc and pad is assumed constant. But under dynamic braking conditions, the frictional heat causes the thermoelastic distortion that leads to more concentrated contact pressure distribution and hence more and more non-uniform temperature. In this paper, to complete the solution of the thermomechanically coupled problem, the linear relation model between pressure and temperature is proposed and demonstrated in examples of a simple two dimensional contact problem. And the two dimensional model has been extended to an annular three dimensional disc model in order to consider more realistic geometry and to provide a more accurate critical speed for automotive brake systems.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.361-366
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• 2002

The deterioration of concrete structure due to corrosion of the reinforcement has created big financial losses on the overall industries. The volume expansion of the corrosion products causes internal pressure to concrete wall around reinforcing bar. If the maximum principal stress induced by internal pressure exceeds the tensile strength of the concrete at any point of time, a crack forms at any point of material. Therefore, in terms of life assessment of concrete structure, it is very important to predict the amount of corrosion products which induces initial concrete cracking. With this objective, this paper proposes the critical amount of corrosion products at interface between reinforcement and concrete using finite element analysis. If an actual survey of corrosion rates could be made, the model might supply information for condition assessment of existing concrete structure. As the mechanical properties of corrosion product and instantaneous geometry of corroded steel are considered in the analysis, the value obtained will be more realistic.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.494_495
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• 2009

This paper presents a study of DFIG wind power generation system for real-time simulation. For real-time simulation, the real-time digital simulator (RTDS) and its user friendly interface simulation software (RSCAD) are used. 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. Stator-flux oriented vector control scheme is applied to stator, rotor side converter control, and back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for realistic and accurate simulation analysis. Block diagrams for DFIG and control scheme of stator, rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.955-960
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• 2004

In this study, three dimensional FE analysis of concrete slab track has been performed in order to develop the realistic design of precast concrete slab track. The precast slab track system including the precast concrete slab panel and the grout layer is modeled using the three dimensional solid element with crack softening effect. The input load is computed from the one dimensional beam element model constituting the rail and several discrete springs. To investigate the effect of the longitudinal connection of slab panels, two different systems-continuous and discrete systems - are modeled. The analytical results show that the stresses of both the slab panel and the grout layer are in the range of linear elastic, and, at the interface between two adjacent panels, the primary stresses of the grout layer of the discrete system are higher than those of the continuous system. However, The overall stress levels of the grout layer are very low relative to the strength of th grout.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1673-1678
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• 2005

This paper addresses both theoretical and experimental studies of the stability of haptic interfaces during the simulation of virtual Coulomb friction. The first objective of this paper is to present an analysis of how friction affects stability in terms of the describing function method and the absolute stability theory. Two different feedback methods are introduced and are used to evaluate the analysis: an active force feedback, using a motor, and a passive force feedback, using controllable brake. The second objective of this paper is to present a comparison of the theoretical and experimental results. The results indicate that the sustained oscillations due to the limit cycle occur when simulating friction with an active force feedback. In contrast, a passive force feedback can simulate virtual friction without the occurrence of instability. In conclusion, a hybrid active/passive force feedback is proposed to simulate a highly realistic friction display.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.75-78
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• 2004

In this paper, we suggest machine control method by the Recognition of Literal Commands. This method that we design is human friendly interface to be able to command easy We distinguish words that is related to command directly or not in the Literal Commands. And vague expressions to move machine directly make behaviors by intelligent recognition model. We suggest The Literal Commands control method that is able to obtain more realistic output equivalent to users' desire throgh the literary style commands. The proposed method is experimentally tested by a mobile car using bluetooth module and mobile phone in real time using Literal language commands.

• Structural Engineering and Mechanics
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• v.46 no.6
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• pp.827-842
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• 2013

In this paper, the wave propagation in generalized thermo elastic plate immersed in fluid is studied based on the Lord-Shulman (LS) and Green-Lindsay (GL) generalized two dimensional theory of thermo elasticity. Two displacement potential functions are introduced to uncouple the equations of motion. The frequency equations that include the interaction between the plate and fluid are obtained by the perfect-slip boundary conditions using the Bessel function solutions. The numerical calculations are carried out for the material Zinc and the computed non-dimensional frequency, phase velocity and attenuation coefficient are plotted as the dispersion curves for the plate with thermally insulated and isothermal boundaries. The wave characteristics are found to be more stable and realistic in the presence of thermal relaxation times and the fluid interaction.

• Journal of Auto-vehicle Safety Association
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• v.7 no.2
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• pp.25-31
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• 2015

This paper presents a performance evaluation procedure for advanced emergency braking (AEB) system. To guarantee the performance of AEB system, AEB test scenario should contains various driving conditions which can be occurred in real driving condition. Also, performances of each elements of AEB system, such as sensor, decision, human machine interface (HMI) and control, should be evaluated in various situations. For this, driving conditions, road types, environment, and elements of AEB system were introduced. Test scenario has been designed to represent the real driving condition and to evaluate the safety performance of AEB system in various situations. To confirm that the proposed AEB test scenario is realistic and physically meaningful, vehicle test have been conducted in two cases of proposed AEB test scenario: subject vehicle cut-out scenario and narrow street turn left scenario.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.596-600
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• 2009

We are developing a simple low-cost wind velocity sensor based on small microphones. The sensor system consists of 4 microphones covered with specially shaped wind screens, 4 pre-amplifiers that respond to low frequency, and a commercial sound interface with multi channel inputs. In this paper, we first present the principle of the sensor, i.e., technique to successfully suppress the influence of external noise existing in the environment in order to determine the wind velocity and the wind direction from the output from a microphone. Then, we present an application for generating realistic motions of a virtual tree swaying in real wind. Although the current sensor outputs significant leaps in a measured sequence of directions, the interactive animations demonstrate that it is usable for such applications, if we could reduce the leaps to some degree.