• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.55-63
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• 2000

This paper is a study on the behavior of Concrete-Filled Square Tubular(CFST) column to H-beam connections reinforced with external stiffeners and reinforcing bar. The cyclic loading tests of 5 test specimens were carried out. The main Parameters are as follows; 1)the length of the stiffener: 200mm, 250mm, 2)the diameter of reinforcing bar: HD16, 19. The results of the researches demonstrate that the increase of the stiffener length was more effective than the increase of the area of reinforcing bar in the point of both strength and stiffness. By reinforcing external stiffeners, stable hysteretic behavior was shown and plastic hinge was formed on the beam flange. Cold-formed tube sections should be used carefully to avoid the welding fracture at the round corners of section, and the proposed welding methods are suitable for this connections.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.1
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• pp.45-50
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• 2014

A vibration test coupon is prepared with nine plastic ball grid array packages on a printed circuit board using SnPb solders, and a random vibration test is conducted on the coupon. Life data from the test are analyzed, and it is shown that over the board, life data is location-dependent. For investigating this location dependency, a finite element model is developed and the equivalent stresses, which are defined based on the stress response functions at each node, are investigated. It is shown that one of the corner solder balls has the maximum equivalent stress at a package during the test. Finally, it is demonstrated that the maximum equivalent stress and durability life are inversely proportional.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.88-93
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• 2010

Many pipes that are arranged longitudinally in ships have loops at intervals to prevent the failure of the pipes as they absorb large portions of the axial load caused by the bending of the hull girder and/or thermal loads when the pipes are carrying very hot fluids. Since the loops are curved at corners, an efficient method for conducting the structural analyses of these curved portions is required. In this paper, a pipe loop was analyzed by an analytical method and by the finite-element method in four different ways, i.e., based on straight-beam elements, curved-beam elements, 2-D shell elements, and 3-D solid elements. The results of the five analyses were compared to check the validity of the current curved-beam theory. The paper includes some suggestions on how to analyze the pipe loops efficiently.

• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.87-93
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• 2012

Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.753-758
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• 2000

Heat engine and fluid machinery in the plant have to linked with various ducts network and the corresponding design have to be concerned about effectiveness and stability of system of plant. To optimum control and design system concerning stability, economization, operating effectiveness we have to exact analysis flow properties of a duct applying to fluid machinery, heat exchanger, cooling machine, air conditioning equipment. therefore, it is necessary to research the duct, heat transfer equipment, for increasing overall effectiveness of air conditioning system by suggesting basic data of the duct resulting from organic research. So we can contribute to technical development of the duct. In case of speeding up the flow rate of the duct, lots of wave velocity components are occurred the value of boundary layer resulting from developing the boundary layer at both walls of duct.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.91-97
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• 1996

This paper deals with a cold forging design system by which designers can determine desirable plans of cold forging design even if they have little experience. In this system, neural networks are used to transform qualitative knowledges to quantitative knowledges. The neural network is learned with three parts which are most important in cold forging design - undercut, narrow hole, sharp corner. The capabilities of the system are illustrated through an example of forging design.

• Digital Contents
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• no.11 s.138
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• pp.85-89
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• 2004

국산 캐릭터업체 10개 업체중 4곳이 불법복제로 골머리를 앓고 있는 것으로 나타났다. 문화관광부와 한국문화콘텐츠진흥원이 발간한‘대 한민국 캐릭터산업백서 2004’에 따르면 캐릭터업체 42.3%가 불법복제에 피해를 불법복제 피해경험이 있다고 응답했다. 매출액별 불법 복제 피해 경험으론 매출액 5억원 미만 업체는 38.3%, 5억,50억원 업체 37.5%, 50억원 이상 업체 65.2%로 인기 캐릭터를 중심으 로 한 불법복제현상이 뚜렷한 것으로 나타났다. 불법복제로 인한 추정 피해액으로는 국산 업체당 4억1,320만원인 것으로 조사됐다. 이처 럼 캐릭터로 인한 피해가 국내에도 크게 늘고 있어 심각한 산업 문제로 대두되고 있다. 이에 이번 호에는 디지털콘텐츠 산업 중에서도 온 라인을 통해 유출되고 있는‘캐릭터’를 중심으로 법적 문제를 다루고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.52-60
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• 1997

This paper proposes the effective method of the software based motion control by using lenear, exponential and bell type discrete filters for acceleration and deceleration of servo motors. Recursive filters are designed in discrete time domain which can reduce computation time and vibration of motors due to load disturbance. Also it deals with the method which decides the time constants of filters when a machine tool is driven at rapid, cutting and jog feedrate. Validity of the proposed method is verified by corner cutting experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.271-273
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• 2023

불수의적인 혀 움직임과 떨림은 다른 신체 부위의 떨림증상이 없이 혀만 움직이는 증상을 말하며, 신경 정신과적 문제와 한의학의 기혈허약 등의 증상에 의해 발생할 수 있다. 혀 영상 촬영 장치로 정면과 측면의 혀를 연속을 촬영하여 혀의 움직임과 떨림을 탐색하려 한다. 혀의 표면은 코너와 같은 특징점을 구하기 어려운 모양이므로 혀의 움직임의 특성을 찾아내는 것은 매우 어려운 일이다. 움직임을 추적하는 방법 중에서 Farnebäck optical flow 방법은 모든 픽셀에 대해서 optical flow를 계산하여 혀의 움직임을 추적할 수 있었다. 이러한 움직임의 크기를 정면과 측면 영상에 대해서 구할 수 있었고, 움직임의 방향도 구할 수 있었다. 혀의 움직임과 떨림에 대한 위치별 정보와 세기 정보를 이용하여 건강상태를 진단할 수 있을 것으로 생각된다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1027-1033
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• 2011

A VCM sheet is a metal sheet on which PET/PVC is coated for outer panels of home appliances. The purpose of this study is to obtain methods for suppressing PET tearing that occurs during the press forming of the VCM sheet. In order to identity the factors that minimize PET tearing, an FE analysis was performed. The occurrence of PET tearing cannot be predicted using the conventional forming limit diagram. PET is torn by friction between a die and sheet, which is caused by the thickening of material at a die corner. To reduce the thickening of material, the blank shape was re-designed and the thickened material at a flange was removed by a trimming process. The results of the FE-analysis involving modified process parameters showed that the thickness of the product at a die corner is distributed within the clearance of drawing and flangeforming process. A forming experiment was conducted to verify the proposed process parameters. A good final product was obtained without PET tearing of the VCM sheet.