• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.374-381
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• 2001

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have tile nogaussian height distrubution. So, in this study, elastic-plastic contact simulations are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface considering the kurtosis is generated numerically. The contact simulation model takes into account the plastic deformation behaviors of asperities by setting a celing on their contact pressure at material hardness value. It will be shown that the performace variables such as real contact area fraction, plastic area fraction and average gap are sensitive to the characteristics of surface geometry according to kurtosis.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.436-442
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• 2005

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. In this paper, characteristics on oscillating heat pipe according to operating conditions (environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated From the experimental results $25^{\circ}C$(environment temperature) R-141b (working fluid) $40\%$ (charging ratio) was best performace at others of inclination angle and the top heating mode of OCHP performed $80\%$ efficiency of the bottom heating mode.

• 지식경영연구
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• 제6권2호
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• pp.47-68
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• 2005

The Purpose of this study is to identify relationships between knowledge management performances and such Influence factors of knowledge Management as information technology, knowledge management process, culture & people, strategy & Leadership in Small and Medium-sized Enterprises. In order to test hypotheses, we collected data from 498 SME's employees, then analysed them by SPSSWIN. This results showed as follows; 1. All Influence factors of knowledge Management( information technology, knowledge management process, culture & people, strategy & Leadership) are to advance individual task effectiveness and organization effectiveness significantly. 2. Such Influence factors of knowledge Management as information technology, knowledge management process, culture & people are to improve business efficiency between the company. But strategy & leadership factor is not significant. 3. Influence factors of knowledge Management are different between knowledge performace factors such ac individual task effectiveness, organization effectiveness, and business efficiency between company.

• 산업기술연구
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• 제43권1호
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• pp.43-48
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• 2023

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) has been considered as one of most promising cathode material, because of its low-cost and competitive energy density. However, 4.7V vs. Li/Li⁺ of high operating potential facilitates electrolyte degradation on cathode-electrolyte interface during charge-discharge process. In particular, commercial polyvinylidene fluoride (PVDF) is not sutaible for LNMO cathode binder because its weak van der waals force induces thick and non-uniform coverage on the cathode surface. In this review, we study high performance binders for LNMO cathode, which forms uniform coating layer to prevent direct contact between electrolyte and LNMO particle as well as modifying high quality cathode electrolyte interphase, improved cell performace.

• 한국응용과학기술학회지
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• 제14권1호
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• pp.61-76
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• 1997

Triacylglycerols of the seeds of Ginkgo biloba have been resolved by high-performace liquid chromatography(HPLC} in the silver-ion and reverse-phase modes. The fatty acids were identified by a combination of capillary gas chromatography and gas-chromatography /mass spectrometry as the methyl and /or picolinyl ester. The main components are $C_{18:2{\omega}6}$(39.0mol%), $C_{18:1{\omega}7}$(asclepic acid 21.5mol%), and $C_{18:1{\omega}9}$(oleic acid, 13.8mol%). Considerable amounts of unusual acid such as $C_{20:3{\Delta}^{5,11,14}$ (5.7mol%), $C_{18:2{\Delta}^{5,9}$(2.8mol%), and $C_{18:3}{\Delta}^{5,9,12}$(1.6mol%), were checked. In addition, an anteiso-branched fatty acid, 14-methylhexadecanoic acid, was also present as a minor component(0.9 mol%). The triacylglycerols were separated into 17 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition numnber(PN) in which a ${\Delta}^5$-non methylene interrupted double bond($^5$-NMDB) showed different behaviour from a methylene interrupted double bond in a molecule with a given cahinlength. Silver-ion HPLC exhibited excellent resolution in which fractions(23 fractions) were resolved on the basis of the number and configuration of double bonds. In this instance, the strength of interaction of a ${\Delta}^5$-NMDB system with silver ions seemed to be weaker than a methylene interrupted double bond system. The principal triacylglycerol species are as follows ; $(C_{18:2{\omega}6)2}/C_{18:1{\omega}7}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$, $C_{16:1{\omega}7}/C_{18:1{\omega}9}/C_{20:3}{\Delta}^{5,11,14}$, $C_{16:1{\omega}7}/C_{18:1{\omega}7}/C_{20:3}{\Delta}^{5,11,14}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $C_{18:1{\omega}9}/C_{18:2}{\Delta}^{5,5}/C_{20:3}{\Delta}^{5,11,14}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$ and $(C_{18:1{\omega}9)2}/C_{18:2{\omega}6}$, while simple triacylglycerols without $C_{18:2{\omega}6})_3$ were not present. Stereospecific analysis showed that fatty acids with ${\Delta}^5$-NMDB system and saturated chains were predominantly located at the site of sn-3 carbon of glycerol backbones. It is evident that there is asymmetry in the distribution of fatty acids in the TG molecules of Ginkgo nut oils.

• 한국정보과학회논문지:시스템및이론
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• 제28권10호
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• pp.520-529
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• 2001

캐리-세이브 가산기(CSA)는 빠른 수행과 작은 면적을 가지는 연산 하드웨어 구현에서 가장 효과적으로 사용되는 연산 셀들 중의 하나이다. 현재 CSA 적용기술의 근복적인 약점을 그 적용이 덧셈식으로 직접 변환되는 부분에 해당되는 회로에만 가능하다는 것이다. 이러한 제한점을 극복하기위하여, 우리는 새로운 몇가지 CSA 변환 기법들을 제안한다. 구체적으로 멀티플렉서를 포함한 연산에서의 CSA 변환, 다수 회로를 포함한 연산에서의 CSA 변환, 곱셈 연산을 내포한 연산에서의 CSA 변화를 제안한다. 또한 이러한 기법들을 실제의회로 합성에서 효과적으로 적용하는 통합 알고리즘을 제안한다. 우리는 다양한 실험을 통하여 제시된 기법들에 기반한 우리의 알고리즘의 기존의 CSA 방법들과 비교하여 실제적인 회로 합성에서 매우 효율적임을 보인다.

• 한국BIM학회 논문집
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• 제5권2호
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• pp.1-11
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• 2015

Despite a lot of research on BIM, there is no quantitative study to measure accurately the performance of BIM coordination service. Thus, this study suggested method to measure the performace of BIM coordination services, applying queueing models in the field of management science. To analyze queuing system of BIM coordination services, a group of BIM coordinator were selected. Through focus group interviews with experts were used in the analysis to derive mean arrival rate(${\lambda}$), mean service rate(${\mu}$) of BIM coordination services. Single-server queuing model(M/M/1), multiple server queuing model(M/M/s) is utilized for the BIM coordination services performance measurement in construction phase. This study has significant quantitative performance measurement approaches that can be utilized in the decision-making for the improvement of the BIM coordination services and to support the review of the alternatives accordingly. But There is a limit but it is difficult to take into account the increase or decrease of the cost of alternatives according to the review.

• 한국항행학회논문지
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• 제6권3호
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• pp.231-240
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• 2002

표적 추적에서 기동은 오랫동안 다루기 어려운 문제로 여겨져 왔다. 이러한 문제를 극복하기 위해 기동을 처리하는 여러 가지 기법들이 연구, 개발되었다. 그러나 이러한 기법들의 연구에 있어 지금까지 기동 검출 기준치의 변화에 대한 필터의 성능의 편차에 대한 연구는 이루어지지 않고 있어 가동에 따른 적절한 기동 검출 기준치의 설정이 객관적인 기준없이 이루어지고 있는 것이 현실이다. 본 논문에서는 가동 표적 추적용 필터에 있어 여러 가지 기동에 대해 기동 유무 검출 기준치의 변화가 필터에 미치는 영향을 알아보고, 이를 분석함으로써 기동과 기동탐지 기준치와 상관관계를 실험적으로 규명하였다.

• 한국농공학회지
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• 제35권3호
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• pp.130-139
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• 1993

In order to evaluate the long-term permeability performace of the geotextiles, for five different combination of geotextiles and soils the long-term column test method The results obtained are as follows; 1.The gradient range of the initial stage of the long-term permeability curves varied with respect to the soil types, while that of the final stage varied according to the interaction of the soil/geotextile system. 2.The time required for a given soil/geotextile system to reach a interactive stable stage was measured ahout 100 hours for the standard sand and 150 to 600 hours for the silty content soils, respectively. 3.There were no differences between the plain woven geotextile and the non-geotextile in the long-term permeability performance. 4.As the silt content increased, the long-term performance of the geotextiles decreased, and the limiting silt content was about 15%. 5.The thickness and area density of the geotextiles did not influence on the variation of the seepage quantities. 6.The ayerage slope and the transition time of the long-time flow curve were calculated. 7.In order to evaluate the mechanism of soil/geotextile system more perfectly, the gradient ratio test or the hydraulic conductivity test is required.

• 한국지반공학회지:지반
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• 제13권2호
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• pp.39-54
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• 1997

연약지반 개량공법으로 국내에서 생산된 플라스틱 보드 드레인(PBD)이 많이 사용되고 있으나 이들에 대한 물리적 성질 및 배수성능의 검증이 미약한 실정이다. 또한 PBD의 웰 레지스턴스(well resistance)에 크게 영향을 미치는 공기(기포)의 영향에 대한 인식이 부족하다고 판단된다. 따라서 본 연구에서는 대형 실험장치를 이용하여 먼저 국산 PBD를 중심으로 물리적 성질 및 배수성능 시험을 실시하여 제품의 질적 수준을 규명하고 대표적인 국외제품과 비교했다. 아울러 PBD재의 꺾임 부분에 누적된 공기(기포)가 통수능력에 지장을 초래하는 것을 재확인하였으며 현장에서 적용할 수 있는 진공펌프를 이용하여 필기(기포)를 제거시키므로써 통수능력의 회복이 가능하다는 것을 나타냈다.