• Journal of the Korea Computer Graphics Society
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• v.4 no.2
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• pp.29-32
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• 1998

When rendering polyhedral models, normal vectors at polygon vertices are necessary for smooth shading. The most commonly used technique of approximating a vertex normal vector by averaging normal vectors of faces around the vertex yields, however, different results on different tessellations Further, continuous deformation of models may cause abrupt discontinuous changes in normal vector directions. In this paper, a variation of the above technique is proposed to avoid these problems. Specifically, it uses a weighted average of normal vectors of faces around the vertex, where the weight of a face being the angular span of the two edges incident on the vertex.

• Journal of the Korean earth science society
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• v.22 no.3
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• pp.179-185
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• 2001

Borehole tests are commonly used as a tool to obtain the physical properties of soils and rocks. The results of borehole tests are, however, discontinuous. Interpolation methods are applied to interpret the data gap between the borehole test points. The interpolation is valid only if the horizontal variations of the ground between the test points are small enough to ignore. A surface wave inversion method was used to study the S wave velocity of the very soft soil to provide the continuous 2 dimensional S wave velocity structure. The resolution of the S wave velocity structure was used to interpret the inversion results.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.5
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• pp.497-502
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• 1997

In this study an automatic rolling-coil labeling system using robot vision system and peripheral mechanism is proposed and implemented, which instead of the manual labor to attach labels Rolling-coils in a steel mill. The binary image process for the image processing is performed with the threshold, and the contour line is converted to the binary gradient which detects the discontinuous variation of brightness of rolling-coils. The moments invariant algorithm proposed by Hu is used to make it easy to recognize even when the position of the center are different from the trained data. The position error compensation algorithm of six degrees of freedom industrial robot manipulator is also developed and the data of the position of the center rolling-coils, which is obtained by floor mount camera, are transferred by asynchronous communication method. Therefore, even if the position of center is changed, robot moves to the position of center and performs the labeling work successfully. Therefore, this system can be improved the safety and efficiency.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.108-116
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• 2003

This research presents the design and analysis of PCDU(Power Control & Distribution Unit) of communication satellite. The PCDU of a spacecraft must provide adequate power to each subsystem and payload during mission life, and it also needs high reliability and performance in space environment. A control circuit of the PCDU include bus sensing and filter circuits, error signal amplification circuit, error compensation circuit of SAS(Shunt Assembly Switch) and BPC(Battery Power Converter). The phase margin and DC gain for the designed circuits are analyzed through the frequency response characteristics of the compensated control circuit. And also the transfer function of the battery power converter circuit are discussed at the battery CCCM(Charge Continuous Conduction Mode) and battery C/DCCM(Continuous/Discontinuous Conduction Mode).

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.11
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• pp.128-139
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• 1999

This paper proposes a linearization technique for the space vector modulation method, which increases the linear control range of inverter up to the 6-step inverter. This method is based on fourier series expansion of the desired output voltage of the inverter to calculate the compensation angle in continuous switching mode and holding angle in discontinuous switching including the 6-step mode respectively. The approximation equation of these angles are used for compensation of fundamental voltage in overmodulation range. Therefore, it is possible to obtain the linear control and the maximized utilization of PWM inverter output voltage.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.6
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• pp.28-36
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• 2001

A robust adaptive sliding mode robot control algorithm is derived, which consists of a feed-forward compensation part and discontinuous control part. The unknown parameters is categorized into two groups, with group containing the parameters estimated on-line, and group containing the parameters not estimated on-line. Then a sliding control term is incorporated into the torque input in order to account for the effects of uncertainties on the parameters not estimated on-line and of disturbances. Moreover, the algorithm is computationally simple, due to an effective exploitation of the structure of manipulator dynamics. It is shown that, despite the existence of the parameter uncertainty and external disturbances, the controller is globally asymptotically stable and guarantees zero tracking errors.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.6 s.46
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• pp.67-73
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• 2005

Precise analysis of soil-structure interaction requires a proper description of soil profile. However, such approach becomes generally nearly unpractical for soil exhibiting material discontinuity and complex geometry since meshes should match that material discontinuity line. To overcome these difficulties, a different numerical integration method is adopted in this paper, which enables to integrate easily over an element with material discontinuity without regenerating mesh fellowing the discontinuity line. As a result the mesh is highly structured, loading to very regular silliness matrix. The influence of the shape of soil profile on the response is examined and it is seen that the proposed soil-structure analysis method can be easily used on soil-structure interaction problems with complicated soil profile and produce reliable results regardless of material discontinuities.

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.189-197
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• 2006

Maglev using EMS becomes unstable by unexpected big air-gap disturbance. The main causes of the unexpected air-gap disturbance are step-wise rail joint and large distance between rail splices. For the stable operation of the Maglev, the conventional system uses the threshold method, which selects one gap sensor among two gap sensors installed on the magnet to read the gap between magnet and guide rail. But the threshold method with a wide bandwidth makes the discontinuous air-gap signal at the rail joints because of the offset in air gap sensors and/or the step-wise rail joins. Further more, in the case of the one with a narrow bend-width, it makes Maglev system unstable because of frequent alternation. In this paper, a new method using fuzzy rule to reduce air-gap disturbances proposed to improve the stability of Maglev system. It treats the air-gap signal from dual gap sensors effectively to make continuous signal without air gap disturbance. Simulation and experiment results proved that the proposed scheme was effective to reduce air-gap disturbance from dual gap sensors in rail joints.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1656-1662
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• 2010

Automatic train control systems are divided into ATC, ATP and ATS systems etc. The ATP and ATS systems offer discontinuous information for train control. While the ATC systems provide continueous information for train control. There is a method for offering continuous information by AF track circuits. Magnetic fields are formed by current through rails in the AF track circuit systems. So, the continuous information is received by the magnetic fields on a on-board antenna. Coating materials on rails are researched to decrease defects such as head check, shelling, corrugation, squats and so on in Germany. Currently, a coating method of rail construction is proposed by using the ceramics in Korea. When deciding physical characteristic of ceramics, researches are required about variation of flux density by the ceramics. In case that the flux density is much lower than existing value, the information for train control is not transmitted to the on-board antenna. In this paper, inductance on rails is calculated and a model is presented about variation of the magnetic field intensity in the AF track circuit. Standard permeability of ceramics is proposed by analyzing the variation of magnetic field intensity. It is demonstrated by using Maxwell and Matlab program.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.37-51
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• 1994

Empty cross-linked chitosan microcapsule was prepared by chemical cross-linking reaction using glutaraldehyde(GA). Chitosan bead was also prepared by coacervation method using sodium hydroxide. The technique involves the formation of a chitosan solution in the discontinuous phase of W/O emulsion. The factors influencing the emulsion stability have been examined to establish optimum conditions Chitosan microcapsules were useful for encapsulation of biological materials, and chitosan bead was useful to prepare the biologically active peptide-bound polysaccharide. As a model compound Gly-His-Lys, cell growth factor, was successfully coupled to chitosan bead.