• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1544-1550
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• 2014

In this paper, an adaptive optimization strategy utilizing Kriging model and genetic algorithm is proposed for the optimal design of electromagnetic devices. The ordinary Kriging assisted by the spherical covariance model is used to construct surrogate models. In order to improve the computational efficiency, the adaptive uniform sampling strategy is applied to generate sampling points in design space. Through several iterations and gradual refinement process, the global optimal point can be found by genetic algorithm. The proposed algorithm is validated by application to the optimal design of a switched reluctance motor, where the stator pole face and shape of pole shoe attached to the lateral face of the rotor pole are optimized to reduce the torque ripple.

• Fashion & Textile Research Journal
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• v.14 no.3
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• pp.448-453
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• 2012

This study aims to categorize age groups for shoes manufacturing including shoes size and boot tree development for Koreans. In order to carry out the research, the characteristics of different parts of foot in relation to size are analyzed according to age and sex, making use of human body measurement database. As a result of statistical analysis, it was found that the measurement items such as foot length, metatarsal tibiale, foot breadth and instep circumference of a person reached the range of standard deviation and average numerical figures of an adult group (18-24) from the age of 14 in men's case, and from 12 for women's case, which indicates the time of completion of their foot growth. Based on these findings where males of 14 years old and females of 12 are within similar measurement range to adults, it is necessary to categorize the age groups for shoe sizing system into the following four groups: males 13 years old or under, males 14 years old or over, females 11 years or under, and females 12 years or over. The proportional measurement produced by dividing each measurement item of foot parts by foot length was compared in an independent samples t-test, and there were meaningful differences according to different foot shapes of the two age groups of males 13 or under - males 14 or over, and females 11 or under - females 12 or over. Also, the independent samples t-test for the age groups of males 13 or under - females 11 or under, and males 14 or over - female 12 or over, showed similar meaningful differences, which indicates the differences in foot shapes of male and female during the period of growth.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.4
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• pp.442-449
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• 2013

This study was to compare a domestic comfort shoes to the popular import(SAS$^{(R)}$) to gain a better understanding in biomechanical characteristics for shoe design for the elderly. For each shoe type, morphologic dimensions, shock absorption, and flexibility were assessed. From subjects(n = 20, $72.4{\pm}5.5$ years, $67.7{\pm}7.9$ kg), mean peak pressure(MPP) and contact area(CA) at the plantar surface were analyzed. The domestic shoes reflecting anatomic contour of the plantar surfaces of Asians resulted in wider CA(by 30.4 $cm^2$), higher shock absorption(by 2.4%) and stiffness(by 0.5 N/mm) than the import. With the domestic shoes, significantly less MPPs were found at the forefoot(by 42~49%) regions(p < .05) and higher CA was noted additionally at hallux and lessor toes(by 26~63%). More anatomically-contoured insole and favorable mechanical characteristics may help reduce the plantar pressures more effectively and more evenly, especially across the central forefoot and midfoot regions of the plantar surface, especially for the design of the comfort shoes for the elderly.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.136-142
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• 2014

A major problem in Switched Reluctance Motor (SRM) is torque ripple, which causes undesirable acoustic noise and vibration. This work focuses on reducing the undesirable torque ripple in SRM by modifying stator and rotor geometry. This paper presents a comparative study on torque ripple minimization in SRM with modified pole shapes such as stator pole taper, stator pole face with non-uniform air gap and pole shoe attached to rotor pole. Further this paper presents a detailed sensitivity analysis of the effect of different geometrical parameters that alter the pole face shapes on the performance of SRM. The analysis is performed using finite-element method considering average torque and torque ripple as performance parameters. Based on the analysis, a design combining stator pole taper with non-uniform air gap is proposed to improve the torque characteristics of SRM. The dynamic characteristics of the proposed design are simulated and the results show satisfactory reduction in torque ripple.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.93-97
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• 2004

This paper is purpose to the design and manufacture of rope brake for elevator. In generally, rope brake systems are second safety device for elevator. Therefore rope brake systems are very important device and very difficult device of design and manufacture. Also, this paper is object to reduced process order and process error.

• Korean Institute of Interior Design Journal
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• no.17
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• pp.30-36
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• 1998

The purpose of this research is to suggest improved storage spaces for each room after taking POE survey of a selected twelve houses which were built according to the standard plan for houses in farming and fishing areas by the government from '94 This research was promoted to suggest suitable storage spaces for each room. The focus being on shoe chest storage in the entrance TV and audio set storage decorated shelves in the living room fixed furniture and storage in the bed room cupboard in the kitchen and storage space in multiple purpose room, Based on the number type NONGJIN-95-25-D which is the most popular type in the standard plan for houses in the farming and fishing areas during 1995. According to the survey those 12 points wee of discomfort and the people preferred fixed and modular furniture based on movable shelves. moveable self-assemblable modular furnishings, The survey can be the fundamental data to make that kind of plan for the farming and fishing and fishing people according to their taste.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1451-1455
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• 2007

MAGLEV(Magnetic Levitation) with Middle-low speed be classified as a kind of LRT(Light Rail Transit) in KOREA. Also this vehicle has adopted LIM propulsion method. The MAGLEV has adopted LIM type in operational or developing model in the world. The power rail of LIM is very similar with the 3th rail of LRT in the functional property but the structure and shape of power rail is different with that. WE have to search the optimal power rail system for Korean MAGLEV vehicle. In this paper, we suggest the conceptual design and direction of design for power rail of Korean MAGLEV developing.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.824-827
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• 2003

Recently, Development of Rare Earth Permanent magnet with the high remanence, high coercivity allow the design of brushless motors with very high efficiency over a wide speed range. Cogging torque is produced in a permanent magnet by magnetic attraction between the rotor mounted permanent magnet and the stator teeth. It is an undesired effect that contributes to the machines output ripple, vibration, and noise. This cogging torque can be reduced by variation of magnet arc length, airgap length, magnet thickness, shifting the magnetic pole and varying the radial shoe depth and etc. In this paper, Some airgap length and magnet arc that reduce cogging torque are found by FEM(Finite element method). The SPM type of high-capacity BLDC motor is optimized as a sample model.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.612-615
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• 2002

The main advantages of Disk type Single-Phase Switched Reluctance Motor (DSPSRM) is the simple construction, rugged structure, low manufacturing cost and simple driving circuit. It is especially possible to make the short axial length of DSPSRM. Therefore, it is suitable to setup this motor in a narrow space. This paper presents the shape design to maximize the average torque of DSPSRM that is achieved by 3D Finite Element Method (3D FEM) considering the nonlinear of magnetic material. The characteristics of two different rotor shapes are compared. The design parameters, such as the rotor and stator pole arc, are selected to the parametric study. The effect of pole arc ratios on the torque performance is investigated. From these results, the optimal pole arc to produce the maximum torque is determined.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.27-31
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• 2010

Torque ripple of the motor used in EPS raises vibration problem on steering system. To solve this problem, this paper proposes a optimum design for torque ripple reduction of Surface-mounted Permanent Magnet Synchronous Motor(SPMSM) in EPS. Through analyis back-EMF using Finite element method as changing the shape of permanent magnet and stator shoe, we presented the method of torque ripple redution.