• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.629-631
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• 2000

This paper deals with the design of a inner rotor type Brushless DC (BLDC) motor for Electric Power Steering to reduce the cogging torque. The effect of the design parameters on the characteristic and cogging torque is analyzed by Finite Element Method (FEM). The considered design parameters are as follows : the number of pole and slot. dead-zone and skew angle. and teeth shape. The winding resistance of each motor is calculated and the characteristic curve is derived from considering reactance drop voltage for original model.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1577-1581
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• 2014

This paper presents a method to minimize torque ripple of a V-type IPMSM using the PSO (Particle Swarm Optimization) method with FEM. The proposed algorithm includes one objective function and three design variables for a notch on the surface of a rotor. The simulation model of the V-type IPMSM has 3-phases, 8-poles and 48 slots with 2 notches on the one-pole rotor surface. The arc-angle, length and width of the notch are optimized to minimize the torque ripple of the motor. The cogging torque of the model is reduced by 55.6% and the torque ripple is decreased by 15.5 %. Also, the efficiency of the motor is increased by 15.5 %.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1465-1467
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• 2005

In this paper, the harbor container crane which transports containers between a container ship and trucks in the harbor is modeled. The equation of motion is simplified for control purpose. The pole placement technique is used to control the crane to minimize load swing angle The objective of the control is to transfer the load as quickly as possible, while minimizing the amplitude of swing at the end of transfer. Computer simulations are provided.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1291-1293
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• 2005

Switched reluctance motors have the advantage a high torque/weight ratio, as the large reluctance torque is made by salient poles of both stator and rotor, and a high reliability. On the other hand, the switched reluctance motors have the disadvantage of a large ripple torque which is made by salient poles. So the application for the industrial fields have been limited to special cases. This paper describes the design of a 12/8 switched reluctance motor using a enemy layer method of the asymmetry rotor. The design is focussed to reduce the torque ripple and radial force in the demanded value. The three dimension finite element analysis method(3D-FEM) was used for decides a enemy layer angle of the asymmetry rotor. This paper presents modifications of the rotor pole shape which reduces the torque ripple.

• Journal of Magnetics
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• v.5 no.4
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• pp.130-134
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• 2000

Using the current-applied pressure-assisted (CAPk) process, we could obtain fully dense isotropic and anisotropic NdFeB magnets from rapidly quenched MQP-A powder. The Nd content is found to play an important role during the current applied (CA)-pressing and CA-deformation processes. The $(BH)_max$ of CA-pressed and CA-deformed magnets are 131 kJ/$m^3$ (16.5 MGOe) and 352 kJ/$m^3$(44.2 MGOe), respectively. The change in texture of CA-deformed anisotropic NdFeB magnets with thickness reduction was investigated by pole figures and the (006) texture was found to increase with greater thickness reductions. As the thickness reduction increases from 50% to 60% to 80%, $W_50$ (the average angle of the contour with 50% intensity) decreases from $76^\circ$to $62.5^\circ$to $17^\circ$.

• Journal of the Ergonomics Society of Korea
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• v.27 no.2
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• pp.83-89
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• 2008

Study was developed the metallic plate for fixation in the femur fracture and plates has a firm place in fracture treatment. This plates can be stabilized for fracture fixation as well as biological and dynamical device. The device's designation and sizing has a optimization with bending structural stiffness and strength, known meaning that is reliable regardless of the plate by the short type and long type. The bending strength of the curved metallic long plate has to evaluate a 11,000N and the bending strength of the curved metallic short plate has to evaluate a 6,525N. This see the X-ray image of bending angle made certain of 15$^{\circ}$ at number 2 and same 82.87$^{\circ}$ at number 2, 4, 5, 7, 8, 9, 10 by outside angle, and confirmed 25.26$^{\circ}$ at number 3, 3.68$^{\circ}$ at number 6, 15.64$^{\circ}$ at number 9 by inside angle. This study shows that keep up the metallic plate for fixation in the femur fracture through X-ray Image and the device can be used to support Revision case of Hip Implant and to use a case of Hip screw compression of Hip Neck Fracture. Short plate have a wrapping of femur and long plate have to preserve a pole of femur.

• Journal of the Ergonomics Society of Korea
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• v.36 no.4
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• pp.305-323
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• 2017

Objective: The purpose of this study was to determine breast shape and ratio of breast enlargement women prior to development of breast enlargement patient's bra. Background: Although there are many previous studies on women's breast that did not undergo breast augmentation surgery, no studies have examined the breast type and proportion of women with breast augmentation. Method: In this study, we analyzed ratios and angles with photographs taken before and after breast augmentation on the frontal and lateral views of the breast, UPF and projection were analyzed too. We also compared the pre-operative and post-operative rates with those of previous breast studies, as well as the post-operative breast types for the desirable breast types. Results: The length and width of the breast base and the height of the breast projection increased after the operation. The rate of increase in width is larger than the vertical distance in the breast base, and the rate of increase in height of the projection is larger than the increase in the width. Specifically, in the vertical distance, the rate of increase in the lower portion is larger than that in the upper portion. In the width, the rate of increase on the inside is larger than that on the outside. Conclusion: The angles of the static relationship with the projection increased and the angles of the minor relation decreased. The changes in the size of the breast were visually observed in the overlapping of the triangle shape before and after the surgery. The changes were composed of the line connecting the angle and the measurement points. The pre-operative upper pole fullness (UPF) was mostly 0 and - 1, but after the surgery, +1, 0, -1, +2 were distributed, while post-operative levels of projection were distributed in the order of level 3> level 1> level 2. In comparison with the desirable breast type, it was found that the anatomical type was a more natural breast type than the round type of implant. Application: These results can be useful as basic data for the breast analysis of breast enlargement patients and their bra patterns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.506-512
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• 2003

An output multiplexer of manifold type is widely used in a recent satellite transponder f3r its mass and volume reduction. For correct operation, the filter of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling matrix are obtained with the aid of orthogonal projection and plane rotation. The rotation order, pivot, and rotation angle of the plane rotation process are given for easy filter synthesis. Two different-structure filters are taken into consideration and the network parameters of each filter have been obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.223-229
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• 2011

When negative electron in x-ray tube is accelerated in to a high speed and then the currency of the electron is blocked by the target, x-ray happens by the conversion of the energy. The real area where the fast accelerated electron collides to a target area is called actual focal spot. When the string focused size is observed at the central ray side, where the direction x-ray comes out, the size seems to be reduced. This focus is called effective focal spot. According to radiation angle of x-rays tube, the degree of the negative pole side presents higher value than inclination, the amount of exposed radiation that patient receives differs by the angle of positive pole, which means effective focal spot is the variable. This paper presents the correlation between size of effective focal spot and amount of exposed radiation to the patient by it, and effective research for homogenized dose dispersion by the size of effective focal spot. In conclusion, following the focal size, effective range which was -8cm ~ 0 cm on average, was found and average dose rate was 0.019 R/min. Through this range, for patients with small radiation exposure, image with good density and resolution in aspect of diagnosing will be able to be obtained.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.77-80
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• 1982

The maneuverabilities of 240 GT class skipjack pole and liner were studied, based on the maneuvering indices and the data which were obtained from Z test of the experimental ship, the m.s. KWANACKSAN, the training ship of the National Fisheries University of Busan. The maneuvering indices K' of the experimental ship were 0.611(at 10$^{\circ}$Z test), 0.622(at 20$^{\circ}$Z test) and 0.556(at 30$^{\circ}$Z test). Her maneuvering indices T' were 1.094(at 10$^{\circ}$Z test), 1.695(at 20$^{\circ}$Z test) and 1.367(at 30$^{\circ}$Z test). The above calculated values K', T' showed that her turning ability at helm angle 20$^{\circ}$ and her obeying ability at helm angle 10$^{\circ}$ were most effective. As it appeared that the calculated K'-values of the experimental ship were smaller than the standard K'-values of different kinds of ships and her overshoot angles at her Z test were greater than those of them, her turning ability was found to be lower. When the experimental ship took a turn at her 10$^{\circ}$Z test, running distance was about 8.3 times her own length and didn't exceed the standard maneuvering distance, 5 to 11 times ship's own length, therefore she was considered to have good maneuverabilities synthetically.