• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.286-297
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• 2016

This study proposes criteria for both optimal-shape and magnetizer-system designs to be used for a high-output spoke-type motor. The study also examines methods of reducing high-cogging torque and torque ripple, to prevent noise and vibration. The optimal design of the stator and rotor can be enhanced using both a response surface method and finite element method. In addition, a magnetizer system is optimally designed for the magnetization of permanent magnets for use in the motor. Finally, this study verifies that the proposed motor can efficiently replace interior permanent magnet synchronous motor in many industries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.4
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• pp.325-331
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• 2002

In this paper, surface acoustic wave(SAW) bandpass filters using slanted finger interdigital electrode transducers(IDTs) are investigated. The slanted finger IDTs are used to design SAW filters with good shape factor, a flat passband, and good out-of-band rejection characteristic. For the filter design, input-output IDT structure was simulated with modified impulse model; uniform-withdrawal weighting IDTs, withdrawal-withdrawal weighting IDTs. SAW filters of uniform-withdrawal weighting IDTs structure were designed and fabricated on $128^{\circ}LiNbO_3$ piezoelectric substrates. Implemented SAW filter has a fractional bandwidth of 30%, center frequency of 70MHz and shape factor of $1.12\pm0.01$.

• Journal of The Korean Astronomical Society
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• v.2 no.1
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• pp.1-9
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• 1969

On the instantaneous tidal relaxation approximation, formulae are derived for the ellipticities and virial theorem of a slightly flattened homogeneous rotating cluster (the largest axis of the cluster is directed towards the Galactic center), in terms of the Galactic tidal force and the characteristic intrinsic plus orbital angular velocity. The expression for a purely tidally-determined ellipticity is identical to that for an incompressible fluid body of uniform density. Orbital motion generally contributes significantly to the shape of the cluster. The virial theorem is identical to that for an isolated cluster except that the gravitational potential energy is multiplied by (1-${\chi}$), where ${\chi}$ is a positive tidal correction term. To obtain the actual mass of a cluster, the virial theorem mass based on an isolated cluster should be multiplied by the factor 1/(1-${\chi}$). The formulae are applied to open star clusters, the globular cluster ${\omega}$ Centauri, and dwarf elliptical galaxies in the Local Group.

• Journal of Applied Reliability
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• v.17 no.4
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• pp.316-324
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• 2017

Purpose: The purpose of this study is to determine the replacement cycle applied age replacement policy by reliability analysis based on railway vehicle contactor's failure history data. Method: We performed reliability analysis based on railway vehicle contactor's failure history data. We found a suitable distribution by goodness of fit test and predicted the reliability through estimation of scale & shape parameter. Considering cost information we determined the replacement cycle that minimize the opportunity cost. Result: Suitable distribution was the Weibull and scale parameter & shape parameter are estimated by reliability analysis. The replacement cycle was predicted and MTTF, $B_6$ percentile life were suggested additionally. Conclusion: We confirmed that failure rate type of railway vehicle contactor is degradation model having a time dependent characteristic and examined the replacement cycle in our country's operating environment. We expect that this study result contribute to railway operation agency for maintenance policy decision.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.131-132
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• 2012

The vacuum plasma coating was performed to analysis the characteristic and find the optimum process conditions for the vacuum plasma spray coating. It was observed that the square shape of powder in case of carbide ceramics does not fluidize well compared to the round shape of powder in case of oxide ceramics so that the plasma spraying is not uniform. The analysis through SEM and EDS mapping shows that the coatings represent excellent structural features with strong resistance against oxidation and satisfied result with vacuum plasma coating.

• Korean Journal of Heritage: History & Science
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• v.33
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• pp.256-273
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• 2000

This thesis attempts to investigate the design of the bracket sets(eave-supporters) of Dapo-style architecture(multiple-bracket architecture) in order to discover the change and the characteristic of the Yon-Hwa-Hyong bracket sets. The external shape of eave-supporters has been evolved as following order: Kyo-Du-Hyong, Soe-Seo-Hyong, Cho-Gak-Soe-Seo-Hyong, and Yon-Hwa-Soe-Seo-Hyong. The internal shape has been developed as following order: Kyo-Du-Hyong. Cho-Gak-Hyong and Yon-Hwa-Hyong. Kyo-Du-Hyong represents the 17th century style and Yon-Hwa-Hyong has been used since the mid 18th century. Cho-Gak-Hyong signifies the transformation in the structural and designing role of column section and middle section and there appears a unified aspect in Yon-Hwa-Hyong. The transformation from Kyo-Du-Hyong towards Yon-Hwa-Hyong suggests that this is an intention of symbolizing the Buddhist teachings inside and outside of the eave-supporters. The purpose of this change establishes the Buddhist land.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.295-301
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• 2024

Understanding the post-liquefaction shear behavior is crucial for predicting and assessing the damage, such as lateral flow, caused by liquefaction. Most studies have focused on the behavior until liquefaction occurs. In this study, we performed undrained multi-stage tests on clean sand, sand-silt mixtures, and silty soils to investigate post-liquefaction shear strain based on soil compressibility. The results confirmed that it is necessary to consider the soil compressibility and the shape of soil particles to understand the post-liquefaction shear strain characteristics. Based on this, an index reflecting soil compressibility and particle shape was derived, and the results showed a high correlation with post-liquefaction small resistance characteristic regardless of soil type and fine particle content.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.3
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• pp.69-77
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• 2011

This study considered the characteristic through the present state of domestic literature museum and grouping by type to help the understanding for domestic literature museum. And conducted a case study on Gyeongsang-do region literature museum to grasp the space form composition characteristic of literature museum. The result gained through these studies is as follows. First, grouping domestic literature museum by type, we can conduct the classification founded on location character, an exhibition writer, and the main body of erection and maintenance management. Second, the classification founded on location character of literature museum is able to be divided into the type of the house of writer's birth, a literary work, writing, and etc. Third, the classification founded on the number of exhibition writers can be divided into the type of independence, an individual pavilion, and integration. Fourthly, the classification founded on the main body of erection and management can be divided into the case in which a local self-governing body is wholly in charge of erection and management, a local government is in charge of erection but entrusts management to a corporate body, etc., a corporate body is in charge of erection and management, and a private person is in charge of erection and management. Fifthly, speaking of the characteristic by type of the Gyeongsang-do region literature museum, the classification founded on location has the type of the house of writer's birth the most, the classification founded on the number of exhibition writers has the type of independence the most, and the classification founded on the main body of erection and management has the most the type in which a local self-governing body is in charge of erection and management. Also, for the characteristic by space form, the case which expresses the character of Korean traditional architecture by form is many the most, and there are pieces of work to pursue shape beauty through the articulation of mass or molding manipulation and the change by space form through the proper combination of concreteness and abstraction as well.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.3
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• pp.72-78
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• 2000

In this study, we propose a model verification algorithm based on DCT and neural network for ATM security system. We construct database about facial images after capturing thirty persons facial images in the same lumination and distance. To simulate model verification, we capture four learning images and test images per a man. After detecting edge in facial images, we detect a characteristic area of square shape using edge distribution in facial images. Characteristic area contains eye bows, eyes, nose, mouth and cheek. We extract characteristic vectors to calculate diagonally coefficients sum after obtaining DCT coefficients about characteristic area. Characteristic vectors is normalized between +1 and -1, and then used for input vectors of neural networks. Not considering passwords, simulations results showed 100% verification rate when facial images were learned and 92% verification rate when facial images weren't learned. But considering passwords, the proposed algorithm showed 100% verification rate in case of two simulations.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.2
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• pp.88-99
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• 2000

As a part of theoretical and experimental research works for the prediction and improvement of ship's maneuvering performance, an experimental study for the optimum rudder design has been carried out. Largely, this study is composed of the investigations on three major characteristics which determine rudder performance, that is, the investigations on section shape, planform and aspect ratio, and the investigation on the special section shapes. Some practically useful design directions and conclusion for each characteristic have been derived through this study. Among special section shapes, dolphin-tail type section shape has shown a possibility of significantly improving rudder performance if utilized as the section of rudders.