• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.289-292
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• 2009

In this paper, an optimum design center frequency proposes portable RFID reader antenna that is 920MHz frequency using the Taguchi's Method. Proposed antenna is cut corner of opposite angle and it's structure that have slots in four sides microstrip patch of a perfect square shape. This slot structure can miniaturize microstrip patch antenna and confirmed through an experiment that size of antenna about 18% decreases than structure that slot does not exist. Because compact antenna that have structure of slot changes according to complex design variables, analysis and experimental design for minimization of experiment number of times are required for optimum antenna design. In this research, designed antenna that have optimum structure when introduce and designs table of orthogonal arrays of the Taguchi's Method been experimental design that can minimize analysis and experiment number of times, achieve responsiveness analysis of main elements and analyzes the effect and minimizes design repeat with analysis result. Presented experiment result about antenna special quality that permittivity is 4.4 and manufactures to board of Epoxy 3.2T.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.21-27
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• 2004

A waterjet propulsion system has many advantages compared with a conventional screw propeller especially for amphibious military vehicles because of a good maneuverability at low speed, good operating ability at shallow water, high thrust at low speed to aid maneuverability and exit from water, etc. Especially, compact design is important for the tracked-vehicle because of buoyancy in water and available space inside the tracked vehicle. The experiment is parametrically performed for various impeller diameters for more compact design. The experimental results are analyzed according to the ITTC 1996 standard analysis method as well as the conventional propulsive factor analysis method. The full-scale effective and delivered power of the tracked-vehicle are evaluated according to the variation of impeller diameter. This paper emphasized the effect of impeller diameter on the performance of waterjet system.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.23-29
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• 2017

This paper introduces the mold technology for the development of ultra-compact package of less than 1mm, and also analyze the error pattern of the results using this mold technology. The existing ultra-small mold structure was one-piece, which caused the surface of EDM to be rough and increase the error rate. This has been an obstacle to further reducing the size of the mold. On the other hand, the proposed mold technology tries to overcome the limitation of the one-piece type by using the prefabricated type method. This paper also classify defect patterns in the results of the proposed mold structure and analyze the occurrence probability of each pattern to use as a basic data to develop a detector.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.766-767
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• 2011

전력 IT 추세에 따라 IED(Intelligent Electronic Device)에서 다양한 기능이 요구되고 있으며, 따라서 이를 구현하기 위한 시스템도 복잡화되어 가고 있다. 또한 IED 내부에서에서 처리하여야 하는 데이터양이 대폭 증가하고 있으며 고속의 처리 속도를 요구하고 있기 때문에 산업용 시스템 버스의 도입 필요성이 제기되고 있다. 산업용 시스템 버스는 오랜 적용기간을 통해 그 신뢰성을 검증받았으며, 호환성이 뛰어나 H/W 플랫폼으로서의 가치가 있다. IED의 경우와 같이 다수 개의 CPU가 요구되는 시스템에서 CPU간 H/W적인 데이터 인터페이스 방식을 어떻게 선정하는지는 매우 중요하며 본 논문에서는 CompactPCI 기반의 최신 기술인 CompactPCI Plus IO와 Serial 기술에 대하여 살펴보고, IED에서 사용되는 기존의 메모리 공유방식이나 저속 시리얼 방식 대신 상기 CompactPCI 기반의 기술을 적용하는 방안에 대하여 검토해 보기로 한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.601-607
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• 2003

The column type is used as the sensing element of the load cell to measure the large force in the range of 10$^4$~ 10$^{7}$ N. However. it is not easy to handle the load with large capacity due to its size. It is, therefore, necessary to design a compact load cell with a low aspect ratio. Thus this paper showed the characteristic evaluation of compact load cell with respect to the shape of supporting plate. The supporting plate of the load cell was an annular type with inner(D$_{i}$) and outer(D$_{o}$) diameters. Using the strain distribution obtained from FEM. the supporting plate was designed to get the stable output voltage of the load cell. The three designed supporting plates were manufactured, and the result of characteristic experiment of the load cell, using the 10 MN hydraulic force standard machine, was compared with FEM.M.M.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.128-140
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• 1997

A new super compact condenser(SCC), which has been developed recently is especially suitable for an alternative refrigerant HFC-134a due to its high performance and compactness. The SCC is composed of two pipe headers, baffles, narrow multi-rectangular channels, and louvered fin arrays. Alternating inlet and outlet by the inserted baffles in pipe headers guide refrigerant to and from the narrow multi-rectangular channels. Since the flow rate and its lengh are changed depending on the number and location of baffles, the corresponding pressure drop and heat transfer rate are changed. The present study aims to theoretically and experimentally investigate the effects of baffle location and its number on the pressure drop and thermal performance of the SCC with 40 multi-rectangular channels. The results show that the present method provides an acceptable prediction of pressure drop and heat transfer rate for a 4 pass SCC. However, the model significantly under predicts the performance of a 3 pass SCC, which may be attributed to the phase separation of refrigerant flowing through header pipes. Pressure drop is more signifi- cantly influenced than heat transfer rate by the baffle location.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.107-114
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• 2007

Porous Ti compacts were fabricated by spark plasma sintering (SPS) method and their in vitro and in vivo biocompatibilities were investigated. Alkaline phosphatase (ALP) activity representing the activity of osteoblast was increased when osteoblast-like MG-63 cells were cultured on the Ti powder surface. Some genes related to cell growth were over-expressed through microarray analysis. The porous Ti compact with 32.2% of porosity was implanted in the subcutaneous tissue of rats to confirm in vivo cytotoxicity. 12 weeks post-operation, outer surface and inside the porous body was fully filled with fibrous tissue and the formation of new blood vessels were observed. No inflammatory response was confirmed. To investigate the osteoinduction, porous Ti compact was implanted in the femur of NZW rabbits for 4 months. Active in-growth of new bone from the surrounded compact bone was observed around the porous body. From the results, The porous Ti compacts fabricated by spark plasma sintering might be available for the application of the stem part of artificial hip joint.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1620-1622
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• 2003

Recently, as the technology for the development of high voltage power apparatus using SF6 gas has made remarkable progress, it became possible to develop more compact power apparatus adopting single body substation system. In these gas insulated power apparatus, it is impossible to achieve perfect and safe insulation using only SF6 gas, because some solid insulation parts should be installed to support current-carrying conductor parts for electrical and mechanical safety. When spacers were installed in SF6 gas insulation system, they were exposed to severe electrical intensification which could reduce system insulation performance and restrict the rated operating voltage So, it is necessary to clarify the dielectric characteristics of spacers by analytically and experimentally, in order to design and develop more compact and optimum gas insulated systems. In this paper, the field distribution of three-phase spacers were investigated using three dimensional electrostatic field analysis tool adopting BEM method. And the obtained results were compared to the conventional two dimensional computations. According to these three dimensional calculations, it was possible to find out weak points in the spacer more clearly and these results could be applied to design more compact and optimum three phase spacer developments.

• Progress in Medical Physics
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• v.31 no.4
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• pp.189-193
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• 2020

An MR-based attenuation correction (MRAC) map plays an important role in quantitative positron emission tomography (PET) image evaluation in PET/magnetic resonance imaging (MRI) systems. However, the MRAC map is affected by the magnetic field inhomogeneity of MRIs. This study aims to evaluate the characteristics of MRAC maps of physical phantoms on PET/MRI images. Phantom measurements were performed using the Siemens Biograph mMR. The modular type physical phantoms that provide assembly versatility for phantom construction were scanned in a four-channel Body Matrix coil. The MRAC map was generated using the two-point Dixon-based segmentation method for whole-body imaging. The modular phantoms were scanned in compact and non-compact assembly configurations. In addition, the phantoms were scanned repeatedly to generate MRAC maps. The acquired MRAC maps show differently assigned values for void areas. An incorrect assignment of a void area was shown on a locally compact space between phantoms. The assigned MRAC values were distorted using a wide field-of-view (FOV). The MRAC values also differed after repeated scans. However, the erroneous MRAC values appeared outside of phantom, except for a large FOV. The MRAC map of the phantom was affected by phantom configuration and the number of scans. A quantitative study using a phantom in a PET/MRI system should be performed after evaluation of the MRAC map characteristics.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.105-113
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• 2013

In this work, using a ${\pi}$-type multiple coupled microstrip line structure (MCMLS) and RCR (Resistor Capacitor Resistor) structure, we fabricated ultra-compact and high isolation Wilkinson power divider on GaAs MMIC (Monolithic Microwave Integrated Circuit). The line length of the Wilkinson power divider was reduced to about ${\lambda}$/46, and its size was 0.304 [$mm^2$], which is 12.1 % of conventional one. Compared with conventional Wilkinson power divider, isolation characteristic of the proposed Wilkinson power divider was highly improved by using RCR insertion method. The proposed Wilkinson power divider showed good RF performances in C/X band.