• Tribology and Lubricants
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• v.24 no.2
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• pp.55-62
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• 2008

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. In this paper, it will be investigated the tendency of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress. Finally, the pressure distributions on the oil film of piston pin bearings will be found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. Specially, it is investigated how the changes in combustion pressure at exhaust and intake stroke and the pressure-viscosity index effect on the film pressure distribution.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.124-125
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• 2009

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• Clean Technology
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• v.14 no.4
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• pp.265-270
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• 2008

In this study, the flow and heat transfer of the aligned pin-fin array of the air cooling module for electronic packaging application were numerically analyzed with various fin shapes. The geometric cross-sectional shapes of pin-fins considered in this study were ellipse, wing and circle. The fins had same cross-sectional area and height, but they had different surface areas. As the results, the surface area, the heat transfer coefficient, and the heat transfer performance of pin-fins greatly depended on their shapes. Of the three types of pin-fins, the wing type pin-fin with suitable shape produced the best heat transfer performance. This result implies that the cooling capacity of the pin-fin cooler can be significantly enhanced only by the change of fin shape without increasing air flow-rate or fin density.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.571-578
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• 2014

As a way of developing wooden joint development, a glass fiber reinforced wood plate was manufactured to replace a steel plate. Also, the fracture toughness was evaluated. Through application to a cantilever-type specimen made of a column and a beam, the moment resistance performance was evaluated. For the fracture toughness specimen of the wood plate, 12 types were manufactured by varying the combination of a main member (veneer and plywood) and reinforcement (glass fiber sheet and glass fiber cloth). The results of the fracture toughness test indicated that the 5% yield load of the specimen using plywood was 18% higher than that of the specimen using veneer, and that the specimen reinforced by inserting glass fiber sheets between testing materials (Type-3-PS) had the highest average 5% yield load 4841 N. Thus, a moment resistance strength test was performed by applying Type-3-PS to a column-beam joint. The results of the test indicated that compared to the specimen using a steel plate and a drift pin (Type-A), the maximum moment ratio of the specimen using a glass fiber reinforced wood plate (Type-3-PS) and a drift pin (Type-B) was 0.79; and that a rupture occurred in the wood plate due to high stiffness of the drift pin. The maximum moment ratio of the specimen using a glass fiber reinforced wood plate (Type-3-PS) and a glass fiber reinforced wooden laminated pin (Type-C) was 0.67, which showed low performance. However, unlike Type-A, a ductile fracture occurred on Type-C, and the load gradually decreased even after the maximum moment.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.120.1-120.1
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• 2017

최근 첨단 기능화 되고 있는 반도체의 회로는 증가하고 칩의 브릿지도 점점 증가하고 있다. 반면에 제품은 소형화되고 회로폭은 미세화 하고, 피치는 감소하고 있다. 이에 회로의 정확한 검사를 위해서는 Probe Pin의 신뢰성을 중요시하게 되면서 도금기술의 고품질화가 요구되는 실정이다. 본연구에서는 Probe Pin과 내구성과 금도금 피막의 두께를 확보하여 국산 반도체 검사장비 시장을 선도 할 수 있도록 금도금피막의 두께와 밀착성 확보와 함께 굽힘시험시 박리와 크랙방지를 위한 기초연구를 수행하고자 하였다.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.481-485
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• 2000

A new type of compliant press-fit pin has been developed and evaluated for use packaging of electronic telecommunications equipments. Main requirements for design are defined the upper limit of pin insertion force and the lower limit of pin retention force. Upper limit of pin insertion force is set to protect the copper plate of the inner PTH wall. Lower limit of pin retention force is set to satisfy a wire-wrapping specification. Results are represented by insertion force and retention force variations according to the front angle, rear angle and material, etc.

• Tribology and Lubricants
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• v.29 no.2
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• pp.85-90
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• 2013

The effects of contact pressure on the sliding wear behavior of mild steel in a pin-on-disc type apparatus were investigated. Sliding wear tests were conducted with various combinations of the load and apparent area of contact. The wear behavior of mild steel as a function of sliding speed was independent of contact pressure. However, the wear rate at different sliding speeds was influenced by the load regardless of the apparent area of contact. This was attributed to the fact that there may be no difference in the real area of contact for any combination of the load and apparent area of contact.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.225-230
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• 1996

A three-dimensional reactor core simulation code, MASTER has been developed as a part of ADONIS which is the Korean core design package in KAERI. CASMO-3 is used as a precedent lattice code for two-group microscopic cross section and heterogeneous formfunctions. The pin power reconstruction capability of CASMO-3/MASTER was evaluated for a validation and verification Five B&W critical experiments were selected as benchmark problems. These problems included two experiments for CE-type and three for WH-type fuel assemblies. Two of them contained gadolinia rods as burnable absorber. Comparison of the calculated pin power distributions with the measured ones demonstrate that CASMO-3/MASTER can predict the pin power distribution as well as CASMO-3/SIMULATE-3.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.622-629
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• 2019

VR(Virtual Reality), which provides realistic services in virtual reality, provides a similar experience using a Head Mounted Display(HMD) device. When the HMD device is worn, it can not recognize the surrounding environment and it is easy to analyze the input pattern of the user with the Shoulder Surfing Attack(SSA) when entering the Personal Identification Number(PIN). In this paper, we propose a method to safeguard the user's password even if the hacker analyzes the input pattern while maintaining the user's convenience. For the first time, we implemented a new type of virtual keypad that deviates from the existing rectangle shape according to the VR characteristics and implemented the lock object for intuitive interaction with the user. In addition, a smart glove using the same sensor as the existing input devices of the VR and a PIN input method suitable for the rotary type are implemented and the safety of the SSA is verified through experiments.