• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.389-392
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• 2004

It is clinically well known that pre-tension of wires increases the fracture stability in ring or hybrid external fixation. In some cases, additional half pin should be necessary to increase the stability when soft tissue impalement occurs during fixation. In this paper, the fracture stability of a hybrid external fixator system with different pre-tension effects and additional half-pins was analysed using FEM to investigate the effects of these pre-tension and half pin on the system stability quantitatively. 3-D finite element models of five different fixator frames were developed using by beam elements. In axial compression analysis, the fracture stiffness was increased maximally 62％ as the pre-tension increased. In torsion analysis, in the other hand, there is little variations in the fracture stiffness. Additional half pin increased the system stiffness about 200 ％. From the results, proper pre-tension and additional half pin would provide good methods to increase the fracture stability of the hybrid external fixator and provide more surgical options to minimize soft tissue damage at the fracture site.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.7-12
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• 2004

Large-sized pins are usually used to lift and handle large low speed diesel engine crankshaft. There has then been a need to reduce and optimize the weight of the traditionally used pins. Making an hole by cutting the inside of the pin out was investigated in view of static and fracture strength. To compensate the stress increase caused by the introduction of the inner hole, the groove in the circumferential direction pre-existing on the pin is to be removed. Finite element analysis was carried out for both the original model and weight reduced model. Stress intensity factors for semi-elliptical defects assumed on the pin for the original model and weight reduced model was calculated using the ASME method and compared with the fracture toughness test result of the pin material. The diameter of the cutting hole for the revised model was determined based on the analysis results.

• Composites Research
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• v.31 no.6
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• pp.323-331
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• 2018

The effect of stainless steel jagged-pin reinforcement on the pull-off strength of the composite hat-joint was studied by the test. The pins were physically and chemically surface-treated and inserted in the thickness direction over the interface where the skin and stiffener meet. The specimens including the jagged-pins were made by co-curing process. Diameters of the jagged-pins were 0.3, 0.5 and 0.7 mm. The pin areal densities were set to 0.5 and 2.0% based on the interface area where the skin and stiffener meet. The specimens using 0.3 mm diameter normal (un-jagged) pins with 2.0% areal density were additionally fabricated and tested to investigate the pin shape effect on the pull-off strength. The pull-off strengths of specimens reinforced with 0.5% areal density by 0.3, 0.5, and 0.7 mm diameter pins were 45, 19 and 9% higher than those of un-reinforced specimens, respectively. In case with 2.0% pin areal density, the strengths were 127, 45, and 11% higher than those of un-reinforced specimens, respectively. The test results show that the higher pin areal density results in the higher strength when the pin diameter is the same. When the pin areal density is the same, the smaller pin diameter leads to higher strength. When the joints using jagged-pins and normal pins in 2.0% areal density with 0.3 mm diameter, the joints of jagged-pins showed the 64% higher strength. From the results of this study, it was confirmed that jagged-pin reinforcement can be an effective method for improving the pull-off strength of composite hat-joint.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.34-39
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• 2009

Four-digit PIN(Personal Identification Number) is a well-known user authentication method used for many applications including ATMs and mobile phones. However, it is vulnerable to shoulder surfing attacks(SSAs). In this paper, we present new PIN entry methods which are secure against SSA and easy to use. We compare the usability and security of these methods with those of the existing methods.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.3
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• pp.105-109
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• 2017

In this paper is proposed wide band reconfiguration antenna by using PIN diode. The proposed antenna consisted of elliptical dipole and exponential taper balun. The proposed new matching method was exponential tapered balun in this paper. The research paper comprised of two PIN diode and Elliptical dipole. This paper used CPW to CPS feed. We obtained a good band width characteristics result by simulating. This antenna is designed to apply ISM and WiFi band.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.797-801
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• 2003

The mechanical properties such as shear strength and the hardness of milli-size products that manufactured for various process parameters by forward extrusion using square dies are investigated. Shear strength test is implemented for the observation of relation between vickers hardness and shear strength in the interface of head and shaft part of a stepped pin. When the extrusion ratios of pure aluminum and pure copper billets increase, the hardness on both the surface and the center line of a pin also increase, especially the hardness on the surface is shown to be a little higher than on the center. The existence of knock-out pad in extrusion die caused hardness increase in the interface of a extruded pin. As compared shear strength with hardness of a pin, the approximated linear relations are suggested in this study.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.171-176
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• 1997

A hair-pin shaped microstrip-line resonator and dielectric resonator for injection-locked oscillators have been designed and fabricated for the comparative studying of their performances. In general, a commonly used dielectric resonator shows lower phase noise value than hair-pin resonator in the free-running mode. In the injection-locked mode, however, a hair-pin resonator is superior to the dielectric resonator, the wider tuning range, the 22% improved locking bandwidth, the lower noise effect, the short term stability, and the higher power level. The planar structure of a hair-pin shaped microstrip-line resonator will be easily applied to monolithic microwave integrated circuits.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2522-2525
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• 2001

Si PIN diodes are subject to be damaged from the exposure of fast neutron by displacement of Si lattice structure. The defects are effective recombination centers for carriers which migrate through the base region of the PIN diode when forward voltage is applied. It causes an increase in current and a decrease in resistivity of the diode. This paper presents the development of a neutron sensor based on displacement damage effect. PIN diodes having various structures were made bymicro-fabrication process, and neutron beam test was performed to identify neutron damage effect to the diode. From a result of the test, it was shown that the forward voltage drop of the diode, at a constant current, has good linearity for neutron dosage. Also it was found that the newton dosage can be measured by the pin diode neutron dosimeter with constant current power.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.349-354
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• 2014

PIN(Personal Identification Number)-based identification method has been used to identify the user of smart cards. However, this type of identification method has several problems. Firstly, PIN can be forgotten by owners of the card. Secondly, PIN can be used by others illegally. Furthermore, the possibility of hacking PIN can be high because this PIN type matching process is performed on terminal. Thus, in this paper we suggest a new identification method which is performed on smart card using face feature information. The proposed identification method uses low-sized face feature vectors and simple matching algorithm in order to get around the limits in computing capability and memory size of smart card.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.409-422
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• 2016

A parametric study based on an unsteady mathematical model of a pyrotechnically actuated device was performed for design optimization. The model simulates time histories for the chamber pressure, temperature, mass transfer and pin motion. It is validated through a comparison with experimentally measured pressure and pin displacement. Parametric analyses were conducted to observe the detailed effects of the design parameters using a validated performance analysis code. The detailed effects of the design variables on the performance were evaluated using the one-at-a-time (OAT) method, while the scatter plot method was used to evaluate relative sensitivity. Finally, the design optimization was conducted by employing a genetic algorithm (GA). Six major design parameters for the GA were chosen based on the results of the sensitivity analysis. A fitness function was suggested, which included the following targets: minimum explosive mass for the uniform ignition (small deviation), light casing weight, short operational time, allowable pyrotechnic shock force and finally the designated pin kinetic energy. The propellant mass and cross-sectional area were the first and the second most sensitive parameters, which significantly affected the pin's kinetic energy. Even though the peak chamber pressure decreased, the pin kinetic energy maintained its designated value because the widened pin cross-sectional area induced enough force at low pressure.