• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.11
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• pp.28-33
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• 2009

Average torque of PMa-SynRM(Permanent Magnet-assisted Synchronous Reluctance Motor) is changed by magnet form inserted to the barrier. Because the magnet structure inserted to the barrier influences to the magnet-torque and reluctance torque. Therefore, this paper present a suitable permanent magnet form design for maximum torque when the magnet quantites are always fixed. And each motor characteristic such as average torque, torque ripple, cogging torque and back-EMF are analyzed by FEM(Finite Element Method) for optimal design.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.815-816
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• 2006

This paper proposes a novel design method for flux barrier which built in q-axis in rotor of IPM type BLDC motor. It aims to reduce the motor vibration with reduced cogging torque and lessened torque ripple by the sinusoidal waveform distribution of flux generated in the permanent magnet, which results from designed flux barriers. Design of flux barrier optimized using the Taguchi methods that considered multiple quality characteristics, such as cogging torque, average torque and efficiency are considered. The result of proposed method is compared and verified with 2D finite element method (FEM).

• Journal of the Korean Ceramic Society
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• v.43 no.8 s.291
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• pp.479-485
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• 2006

The residual stress changes on thermo-mechanical loading in the interface region of the Thermal Barrier Coating (TBC)/Thermally Grown Oxide (TGO)/Bond Coat (BC) were calculated on the TBC-coated superalloys using a Finite Element Method (FEM). It was found that the residual stress of the interface boundary was dependent upon mainly the oxide formation and the swelling rate of the oxide by creep relaxation. During an oxide swelling, the relaxation of residual stress which is due to creep deformation increased the TBC's life. In the case of the fine grain size of TGO scale, the TBC stresses piled up by oxide swelling could be relaxed by diffusional creep effect of TGO.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.660-662
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• 2000

It is demonstrated that the torque performance of the flux barrier type synchronous reluctance motor(SynRM) can be improved in terms of geometric parameters. Torque ana power factor are related to the difference of inductances and the saliency ratio. And these inductance characteristics are determined by the geometric parameters of rotor: the number of layers. the width of iron to the width of flux barrier($K_w$). slot number and shape, airgap, bridge, etc. The relationship between geometric parameters. especially, $K_w$ and motor performance will be studied. This paper shows that torque and power factor are improved through redesign with considering geometric parameters. Performance comparisons of proto type SynRM and improved SynRM are given by FEA(Finite Element Analysis).

• Journal of the Chungcheong Mathematical Society
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• v.33 no.1
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• pp.165-171
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• 2020

In this paper we consider a mixed fractional Brownian motion (mfBm) with jumps. The prices of European barrier options can be evaluated by solving a partial integro-differential equation (PIDE) with variable coefficients, which is derived from the mfBm with jumps. The 2-step backward differentiation formula (BDF2 method) proposed in [6] is applied with the second-order convergence rate in the time and spatial variables. Numerical simulations are carried out to observe the convergence behaviors of the BDF2 method under the mfBm with the Kou model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.48-53
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• 2014

Generally, the usage motor in the vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering starting current of Brushless DC Motor (BLDCM) through Finite Element Method(FEM). As a result, the end of Permanent Magnet (PM) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barrier was limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.10
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• pp.47-53
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• 2015

IPMSM(Insert Permanent Magnet Synchronous Motor) is a very high degree of freedom in the design according to the permanent magnet insertion position. And the performance of IPMSM is affected a lot on barrier shape which determines the magnetic flux path from magnet. Thus the position of permanent magnet and the barrier shape has to be designed by considering both specification and operation condition. In the paper, the permanent magnet and barrier shape which is suitable for direct drive motor of washing machine has been studied. In addition, in order to verify the validity of the study, the test was evaluated by making a prototype motor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.578-581
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• 2004

In this paper numerical and experimental studies are conducted to examine the wave screening effectiveness of wave barriers. The numerical study is based on a finite element model of a 'sandbox' with Lysmer-Kuhlemeyer-type absorbing boundaries. Using the model, the screening effectiveness of wave barriers is studied for different barrier dimensions and distances between the source/receiver and the wave barrier. The results of the numerical modeling are compared with those of the ultrasonic experiment which is performed on an acrylic block with a drilled rectangular cut. Finally, the problem of ground transmitting vibration from a traveling train is numerically treated as a real-world application and the results are discussed in some detail.

• Water Engineering Research
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• v.2 no.2
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• pp.75-87
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• 2001

A new moving boundary technique for leap-frog finite difference numerical mode is proposed for the resonable simulation of coastal inundation over discontinuous topography. The new scheme improves the moving boundary technique developed by Imamura(1996). The present scheme is tested using the analytical solution of Thacker(1981) for the case of free oscillation with moving boundary in a parabolic bowl. Finally, a numerical simulation is conducted for the flooding over a tidal barrier constructed on a simple concave geometry. A general feature of inundation over a discontinuous topography is well described by the numerical model.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1130-1135
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• 2003

The need to increase the reliability of a structural system has been significantly brought in the procedure of real designs to consider, for instance, the material properties or geometric dimensions that reveal a random or incompletely known nature. Reliability based design optimization of a real system now becomes an emerging technique to achieve reliability, robustness and safety of these problems. Finite element analysis program and the reliability analysis program are necessary to evaluate the responses and the probabilities of failure of the system, respectively. Moreover, integration of these programs is required during the procedure of reliability based design optimization. It is well known that reliability based design optimization can often have so many local minima that it cannot converge to the specified probability of failure. To overcome this problem, barrier function method in reliability based design optimization is suggested. To illustrate the proposed formulation, reliability based design optimization of a bracket is performed. AMV and FORM are employed for reliability analysis and their optimization results are compared based on the accuracy and efficiency.