• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.10 s.103
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• pp.1211-1216
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• 2005

Underwater acoustic transducers are widely used for SONAR application, whose important design parameters are shapes. materials, dimensions and supporting structures. Practical design method of transducers consists of manufacturing, experiments and modifications so that it requires much time and expenses. In this study, an analytical method was developed for the Tonpilz type transducers using the commercial finite element analysis code ATILA which can solve the electro-mechanical coupling problems. A finite element model was established including the transducer elements such as ceramic stack, head mass, tail mass, tensile bolt, and molding layers. The proposed model was verified and modified by comparing the in-air and in-water test results of prototypes. The developed analysis method will be effectively used for the sensitivity analysis of design parameters in transducer design process.

• The korean journal of orthodontics
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• v.45 no.2
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• pp.66-73
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• 2015

Objective: To compare condylar position and morphology among different vertical skeletal patterns. Methods: Diagnostic cone-beam computed tomography images of 60 adult patients (120 temporomandibular joints) who visited the orthodontic clinic of Hallym University Sacred Heart Hospital were reviewed. The subjects were divided into three equal groups according to the mandibular plane angle: hypodivergent, normodivergent, and hyperdivergent groups. Morphology of the condyle and mandibular fossa and condylar position were compared among the groups. Results: The hypodivergent and hyperdivergent groups showed significant differences in superior joint spaces, antero-posterior condyle width, medio-lateral condyle width, condyle head angle, and condylar shapes. Conclusions: Condylar position and morphology vary according to vertical facial morphology. This relationship should be considered for predicting and establishing a proper treatment plan for temporomandibular diseases during orthodontic treatment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.246-249
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• 2009

Due to the additive white Gaussian noise (AWGN), images are often corrupted. In recent days, Bayesian estimation techniques to recover noisy images in the wavelet domain have been studied. The probability density function (PDF) of an image in wavelet domain can be described using highly-sharp head and long-tailed shapes. If a priori probability density function having the above properties would be applied well adaptively, better results could be obtained. There were some frequently proposed PDFs such as Gaussian, Laplace distributions, and so on. These functions model the wavelet coefficients satisfactorily and have its own of characteristics. In this paper, mixture distributions of Gaussian and Laplace distribution are proposed, which attempt to corporate these distributions' merits. Such mixture model will be used to remove the noise in images by adopting Maximum a Posteriori (MAP) estimation method. With respect to visual quality, numerical performance and computational complexity, the proposed technique gained better results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.56-61
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• 2010

Scanning head has used to detect the error signal in register controller. However the resolution of the system is not enough for E-printing(Electronic-paper printing). In this paper, the register mark shapes and process techniques are studied using a smart camera which can detect the register mark and calculate the printing error. With these, a register controller within 10[um] of error range is developed for e-printing system and confirmed with experiments.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.391-396
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• 2003

A cross-flow fan relatively produces higher dynamic pressure at low speed because a working fluid passes through an impeller blade twice and blades have a forward curved shape. The performance of a cross-flow fan is influenced 25% by the impeller, 60% by the rearguider and the stabilizer, and 15% by the heat exchanger. At the low flow rate, there exist a rapid pressure head reduction, a noise increase and an unsteady flow against a stabilizer and a rearguider. The purpose of this study is to investigate the reciprocal relation among each parameter Experiments are conducted to study the effects of a rearguider and a diameter ratio of impeller on the performance analysis of a cross-flow fan. Comparing with the rearguider of radial type, the Archimedes type shows excellent results for various diameter ratios.

• The KSFM Journal of Fluid Machinery
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• v.14 no.4
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• pp.45-51
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• 2011

The kimchi refrigerator is the electronic home appliance which is used for the maturing and a custody of the kimchi. In this paper, performance improvement of fan and duct system for kimchi refrigerator has been studied by using a commercial CFD code. In order to achieve a improved fan performance, three-dimensional computational fluid dynamics and the Design of Experiments method have been applied. Additionally, to know the optimized duct inlet shape with the optimized fan, the overall performances were calculated with various duct inlet shapes. The final fan and duct system for kimchi refrigerator showed improved performance in efficiency and total head compared with the existing model.

• International Journal of Fluid Machinery and Systems
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• v.9 no.4
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• pp.362-369
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• 2016

The shock-free inflow criterion applied in the development of two-dimensional cascade for turbomachinery design. The developed cascade analysis with potential flow calculation through a panel method has been used to determine the shock-free inflow condition. The combination between cascade analysis and PSO (particle swarm optimization) algorithm provides an opportunity to develop a diagram of a two-dimensional parameter cascade at various airfoil shapes. Analytical equations have been derived from the diagram that will facilitate the turbomachinery designer in applying the shock-free inflow criterion on their developed cascade. This method has been used to develop the very low head axial hydraulic turbine and provides excellent results of numerical and actual prototype performances.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.247-250
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• 2005

Underwater acoustic transducers are widely used for SONAR application, whose important design parameters are shapes, materials, dimensions and supporting structures. Practical design method of transducers consists of manufacturing, experiments and modifications so that It requires much time and expenses. In this study, an analytical method was developed for the Tonpilz type transducers using the commercial finite element analysis code ATILA which can solve the electro-mechanical coupling Problems. A finite element model was established including the transducer elements such as ceramic stack, head mass, tall mass, tensile bolt, and molding layers. The proposed model was verified and modified by comparing the in-air and in-water test results of prototypes. The developed analysis method will be effectively used for the sensitivity analysis of design parameters in transducer design process.

• Journal of the Korean Society of Costume
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• v.35
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• pp.91-109
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• 1997

This study was conducted to find a more rational way of inheriting and developing tra-ditional Korean HanBok children wear by means of looking at the color and shapes of traditional Korean HanBok and also to find a way to apply this to today's children HanBok wear. The process taken was first to study re-lated literature and its theories and to research museums to find what few traditional HanBok there are and then to compare these findings with new books and personal pieces kept by individuals. We also compared with HanBok children wear now sold at markets. The results of these findings show the fol-lowing conclusions and recommendations: We have found that modern children HanBok utilized the same yellow blouse and red skirt combination as before. These nearly in all cases represented the colors for girls. To most koreans these combination colors are a representation of traditional children wear nat-urally accepted by most koreans without any resistance. Also a definite relation with tra-ditional and modern children wear in the sense of color and shape wear hard to substantiate but we could find harmony between the two. In other words a mixture of modern shapes and traditional colors could be found or vice versa. This is an important factor to be con-sidered when trying to inherit traditional hanBok cuture. Modern times has seen great change in lifestyle feelings and social environ-ment,. In order to create harmony between tra-dition and present day customs a certain mix-ture is required. Therefore we need to maximize traditional flavor and design with present day design emotions. Another issue is that right now children hanBok is only being utilized on a restricted scale. It is a shame that in today's children HanBok that added to the skirt pants and overall wear that the head wear purse and other accessories are not being used. There-fore the HanBok culture especially for the correct succession of children hanBok must refrain from such restricted use of accessories and work to advertise the widespread use of proper Hanbok wear thereby upholding the rightful use of HanBok. As I have mentioned in my other studies it is ones momory of early HanBok wear which greatly affects a grown-up so we should wear hanBok in the right way from an early age and become accustome to its shapes and colors thereby become friendly with traditional HanBok wear. This I believe will lead to overcoming prejudice and disapproval of hanBok and to a more affirm-ative view towards our cultural heritage, Looking from a design point of view inter-national design of a nation's traditional wear can only come from a correct understanding of ones traditions this then becoming a foun-dation for creative design. Seen from these aspects a re-cretion through the meaningful activities of studying traditional shapes and colors of hanBok is the beat way to forming a true HanBok tradition.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1048-1054
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• 2011

Laser surface hardening process is the method of hardening surface by inducing rapid self quenching of laser injected area through transfer of surface heat to inside after rapid heating of laser injected area only by high density energy heat source. This surface treatment method does not involve virtually any thermal deformation by heat treatment nor accompanies any other process after surface hardening treatment. In addition, allowing local machining, this method is a surface treatment method suitable for die with complicated shape. In this study, die material cast iron was surface-treated by using high power diode laser with beam profile suitable for heat treatment. Since the shapes of die differ by press die process, specimens were heat-treated separately on plane and corner depending on the applied parts. At this time, corner heat treatment was done with optic head inclined at $10^{\circ}$. As a result, corner heat treatment easily involves concentration of heat input due to limitation of heat transfer route by the shapes compared with plane part, so the treatment accomplished hardening at faster conveying speed than plane heat treatment.