• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.369-377
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• 1997

The torque converter, a major part of automatic transmissions, has many difficulties in analysis due to the factors such as power transmission through fluid flow, complex internal geometry, and various operating conditions. Because of such difficulties, the dynamic analysis and design of a torque converter are generally carried out by using equivalent performance model which is based on the concept of mean flow path. Since the design procedures of a torque converter are essential technology of automotive industry, the details of the procedures are rarely published. In this study, the basic design procedures of a torque converter are systemized and coded based on the equivalent performance model. The mathematical methods to deal with mean flow path determination and the core-shape are developed. And by using this model, the method of determination of performance parameters satisfying the requested performance is proposed. Finally, to embody the three-dimensional shape, the intermediate blade angles which maximize the tractive performance are determined and laid out.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.11-11
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• 2000

Large-size ceramic/metal bulk FGMs have been fabricated on a recently developed and the world's largest Spark Plasma Sintering(SPS) systems, As a part of the development program for practical production processes and machines for FGMs by SPS, the processes, mechanical properties, dimensional size and shape effects, and production machine systems were investigated. In the past, $ZrO_{2}$/TiAI, $ZrO_{2}$/Ni, $Al_{2}O_{3}$/Ti, WC/Co, WC/Co/Steel, A1/P, Polymide, Cu/Polymide, nano-composites, porous and other combinations of bulk FGMs have already been processed using SPS. However, most of the specimen sizes were small, in a range of 20 to 30mm in diameter. Recently disk-shape sintered compacts with diameters of 100 and 150 mm, and thickness of approximately 15 and 17 mm, $ZrO_{2}$(3Y)/ stainless steel FGMs were homogenous consolidated in a shorter sintering time, while maintaining high quality and repeatability by utilizing a temperature gradient sintering method. The SPS heating up and holding time totaled less than one hour. Therefore, the SPS process in expected to find increased use in the fabrication of large-size FGMs as a new industrial processing technology. This paper introduces SPS systems, the processing principles, features and the characteristies of ceramic/metal bulk FGM.

• The Journal of the Acoustical Society of Korea
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• v.33 no.3
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• pp.174-183
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• 2014

When a active sonar signal is transmitted and returned back from a target, it has been distorted by various properties of acoustic channel such as multipath arrivals. And signals have been appeared to be different form by target position and attitude. Therefore, we simulated the target echo signal using 3 dimensional target model include reflects target features. In this paper, we develop components form of a simulated target model is made up equally spaced highlight points, and each part of the target consists of shape function. We can simulate a target echo signal and Target strength (TS) according to wave incident angle. To verify, we made small scale target in kit form and we had got underwater target signal for comparing simulation result in water tank.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.62-65
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• 2003

VLM-ST process requires an additional human interaction due to the manual stacking and bonding. Hence, building time, building cost and the part quality are dependent on the skill of labor. In this present work, a novel rapid prototyping (RP) process, as an automatic VLM-ST (VLM-STA), has been proposed to improve building efficiency of VLM-ST process and reliability of products. The apparatus of VLM-STA is designed to embody the process. Several characteristics of the proposed process and the apparatus are discussed. In order to examine the efficiency and the applicability of the proposed process, various three-dimensional shapes, such as a piston and a human head shape, are fabricated on the apparatus.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.10-16
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• 1995

In this study, the optimum design is carried out upon the crankshaft of in-line 6-cylinder internal combustion diesel engine with the mechanical analysis for the layout design, which is standard calculation whose process contains quadratic curve fitting method and quasi newton method about cost function, design variables and constraint conditions, Without finite element analysis, this process in wich mechanical analysis is performed upon the most critical part in crankshaft gives necessary and satisfied output in layout design and saves time and cost in developing a new diesel engine. In this study, also, the 3-dimensional finite element method is used in confirming the standard calculation for the optimization of crankshaft and the shape optimization in crankweb is obtained.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.3
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• pp.231-240
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• 2012

During the past two decades, Metal Injection Molding(MIM) has become a very competitive technology to fabricate small, precise and complex-shaped parts in large quantities. In this research, the applicability of MIM technology in the mass-production of the high precision fuze parts to save manufacturing cost was investigated. The water-atomized 17-4PH stainless steel powder, one of the best corrosion-resistant high strength materials, was injection-molded into real-shape fuze part and flat tensile specimens. The injection-molded parts were thermally debound in hydrogen gas flow without solvent extraction. Sintering of the debound parts was carried out in vacuum at temperatures ranging from $1150^{\circ}C$ to $1370^{\circ}C$. The sintering behavior, mechanical properties, dimensional precision, corrosion resistance of the MIMed 17-4PH stainless parts were investigated. It was found that almost all the properties of the MIMed parts were comparable to those of the mechanically machined parts. Also, actual military field tests using both MIMed and mechanically machined fuze parts were performed as well and were found to be very successful.

• Journal of the Korean Society of Costume
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• v.52 no.3
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• pp.149-160
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• 2002

Symbolism found in a certain object inherits characteristics from the culture that contains the objects. The purpose of this study was investigate the formative beauty of Korean trousers twisted the pieces together based on the way of Korean thinks and the Topology. The shape is formed by cutting from the fabric. From the perspective of semiology, the fabric and the pattern shape correspond to ground and figure. Ground and figure are identical with the principle of the whole and the part, which is the same in Korea, China, and the West. But In Korea, the 3-dimensional garment is made by adding a twist. This is very important and defines the difference in the way of thinking and topology. Korean trousers consist of three parts : Hury, Marupok, and Sapok. The small Sapok can be made by removing the Marupok and large Sapok (figure) from the fabric (ground) when making Korean trousers. A Mobius strip is made when the large Sapok is adjoined with the small Sapok by reversing the small Sapok, making a 180$^{\circ}$twist and then stitching together. The theory of Mobius strip can be applied in Joining Bajiburi. thus when the trousers are completed the Klein's bottle is seen because of the 2 existing Mobius strop. The theory of Mobius strip can be applied in Joining Bajiburi, thus when the trousers are completed the Klein's bottle is seen because of the 2 existing Mobius strip. Hury is cylinder while the small and large Sapok make up the Mobius strip. As a result, Mobius strip, Kleins'bottle, protective plan can be applied in cutting Hanbok used in the countryside, so I have come to see that the traditional Korean way of thinking is closely related to the theory of topological.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.85-91
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• 2006

This study deals with the flow over a flat plate with repeated roughness elements of 2-dimensional rectangular shape, which can be applied into the study on the natural geographical roughness and the turbulent flow on roughened solid surface. Part 1 of the study showed that the ratio between the spacing and the height of roughness elements plays a crucial role in developing the flow pattern near wall surface. The present study complements the turbulence characteristics, the utilization of friction velocity as well as integral parameters. Results confirmed that k-type roughness(s/H=7 or 14) is certainly a more effective means than d-type roughness (s/H=3.5) in thickening the viscous region.

• Korean Journal of Computational Design and Engineering
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• v.10 no.6
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• pp.432-443
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• 2005

Recent three-dimensional feature-based CAD systems based on solid or non-manifold modelling functionality have been widely used for product design in manufacturing companies. When product models associated with features are used in various downstream applications such as analysis, however, simplified and abstracted models at various levels of detail (LODs) are frequently more desirable and useful than the full detailed model. To provide multi-resolution models, the features need to be rearranged according to a criterion that measures the significance of the feature. However, if the features are rearranged, the resulting shape is possibly different from the original because union and subtraction Boolean operations are not commutative. To solve this problem, in this paper, the new concept of the effective zone of a feature is defined and identified using Boolean algebra. By introducing the effective zone, an arbitrary rearrangement of features becomes possible and arbitrary LOD criteria may be selected to suit various applications. Besides, because the effective zone of a feature is independent of the data structure of the model, the multi-resolution modelling algorithm based on the effective zone can be implemented on any 3D CAD system based on conventional solid representations as well as non-manifold topological (NMT) representations.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.14-32
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• 2016

This study examines the morphological expression type and formative characteristics of women's shoes designs that integrate 3D printing technology. The results of the study are as follows. First, the morphological expression types of contemporary shoes that integrate 3D printing technology express a structural form created by repetition. Second, it expresses a dynamic form, which combines organic curves that create an external volume. Third, it expresses a surrealistic form centered on an object with the creation of a unique shape that utilizes objects easily experienced in local surroundings. Fourth, it expresses a hybrid form on a partial derivation. Each of the other system's components are fused to create another beauty that develops a new value in a colorful variation on the shape of 3D printing shoes. The first formative characteristic of women's shoes designs that integrate 3D printing technology is continuity. This creates an invisible form of a new space through repetitive unidirectional layers with a gradual expansion of a unitary seamless curves. Second, it is an exaggeration. This exaggeration elicits an enormous aesthetic quality by structuring the outward space in the difference of the volume formed based on the maximization of a specific part and the volume of a line's atypical movement. Third, it is a decoration. It displays the beauty of a decoration that evokes a unique artistic inspiration by partial unification or a practical representation of a specific form. This can also be seen as superimposing a 3D printing figure that has an outstanding shape onto part of the fashion shoes. Fourth, it concerns a geometrical characteristic that formulates a new structure with rationality in combining basic shapes such as circles, triangles and squares with lines, hexagons and interconnected geometrical forms to create a multi-dimensional space for shoes in a systematic and unidirectional pattern.