• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.83-86
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• 2004

Carbon nanotube (CNT) tips in tapping mode atomic force microscopy (AFM) enable very high-resolution imaging, measurements, and manipulation at the nanoscale. We present recent results based on experimental analysis that yield new insights into the dynamics of CNT probe tips in tapping mode AFM. Experimental measurements are presented of the frequency response and dynamic amplitude-distance data of a high-aspect-ratio multi-walled (MW) CNT tip to demonstrate the non-linear features including tip amplitude saturation preceding the dynamic buckling of the MWCNT. Surface scanning is performed using a MWCNT tip on a SiO$_2$ grating to verify the imaging instabilities associated with MWCNT buckling when used with normal control schemes in the tapping mode. Lastly, the choice of optimal setpoints for tapping mode control using CNT probe tip are discussed using the experimental results.

• 통상정보연구
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• 제6권1호
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• pp.3-23
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• 2004

Since the mid-1980's, strategic alliances are dominantly hailed as an effective growth and survival strategy in the era of international market and multinational corporation. There are a number of reasons for this phenomenon. there is an increasing globalization of markets in an ever-widening band of industries, together with the development of global technologies that makes production cycles shorten and the ever-increasing demand for investment resources and information to cope with the changing environment. The purpose of this study is to investigate the determinants of corporation information system in strategic alliance mode, and to analyze the main factors which are affecting the choice of strategic alliance mode by Korean firms. This study can also contribute theoretical and practical suggestive points in relation to strategic alliance operations. However, it also has limits as an exploratory study due to lacks of prior studies and proper methodologies and so on. Accordingly, the phenomenon of international strategic alliances call for further studies on casual relationships between main factors and variables in this field.

• 한국철도학회논문집
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• 제16권1호
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• pp.59-64
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• 2013

본 논문에서는 교통카드 데이터를 활용하여 지역 간 철도역(서울역)을 중심으로 유입과 유출통행에 이용된 대중교통 수단을 중심으로 지역별 통행패턴을 분석하고 이들 통행에 대한 대중교통 수단선택의 문제를 도시철도와 버스로 구분하여 분석하였다. 서울역으로의 유출입 통행특성을 분석한 결과, 서울역으로의 유출입통행은 1번 이내의 환승으로 통행한 경우가 99%로 나타났다. 유출입 통행수단으로는 버스보다 도시철도를 이용한 비율이 높았으며 서울역에서 가까운 지역에서 버스의 이용율이 높게 나타났다. 버스와 도시철도의 수단선택 행태분석을 위해 이항로짓모형을 구축했으며, 그 결과 지역간 철도역유출입통행 수단선택에 있어 통행요금보다는 통행시간의 영향이 더 큰 것으로 나타났으며 특히 유출통행에서 매우 큰 영향을 가지는 것으로 분석되었다.

• 응용통계연구
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• 제26권4호
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• pp.623-634
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• 2013

본 연구에서는 교통 분석존(서울시 행정동) 단위별로 대중교통 수단(버스, 도시철도)선택에 있어서 공간 상관성이 존재하는지 여부를 대중교통카드 자료를 기반으로 제시한다. 분석결과 버스를 탑승한 비율이 높은 지역들이 서로 이웃하여 그룹을 형성하고 있으며, 이들 지역은 도시철도 역사의 수가 버스 정류장에 비해 매우 적기 때문인 것으로 분석되었다. 버스에 탑승한 비율이 비슷한 그룹 간에는 공간 상관성이 존재하는 것으로 통계분석결과 나타났으며, 이러한 공간상관성은 향후 대중교통 수단선택 모형 구축에 고려할 수 있을 것으로 판단된다. 대중교퉁 수단선택에 있어 공간상관성의 존재는 대중교통 운영기관이 향후 대중교통카드를 기반으로 대중교통 노선계획, 운영계획을 수립함에 있어 중요한 정보가 될 것으로 기대된다.

• 한국재료학회지
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• 제28권10호
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• pp.544-550
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• 2018

The passivation of AZ91D Mg alloys by plasma anodization requires deliberate choice of process parameters due to the presence of large amounts of structural defects. We study the dependence of pore formation, surface roughness and corrosion resistance on voltage by comparing the direct current (DC) mode and the pulse wave (pulse) mode in which anodization is performed. In the DC plasma anodization mode, the thickness of the electrolytic oxide film of the AZ91D alloy is uneven. In the pulse mode, the thickness is relatively uniform and the formed thin film has a three-layer structure. The pulse mode creates less roughness, uniform thickness and improved corrosion resistance. Thus, the change of power mode from DC to pulse at 150 V decreases the surface roughness (Ra) from $0.9{\mu}m$ to $0.1{\mu}m$ and increases the corrosion resistance in rating number (RN) from 5 to 9.5. Our study shows that an optimal oxide film can be obtained with a pulse voltage of 150 V, which produces an excellent coating on the AZ91D casting alloy.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.330-344
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• 2023

This research report cuts across management sciences (market strategy entry mode development) and innovative technology (Electric Vehicle (EV)) alongside measures to submerge global warming. The development of a successful entry mode for the electric Vehicle into the African continent is the main objective of the study. The study focuses on an analysis of how electric car manufacturers can enter the African market in other to achieve global sustainability and social responsibility. The methodology is based on identifying the factors that affect the choice of an entry mode into international markets by multinational companies desiring to leverage their revenue through a foreign market. It also offered a quantitative approach that can support the economic and sustainability entry mode model for EVs and a qualitative approach of Porter's five forces analysis as an entry mode coaching tool for EVs. These proxies are used in quite a wide range of multivariate statistical methods (trend analysis, ratio, and probability, comparative t-test technique, auto-regression, and ordinary least square technique). The result acknowledges joint venture and setting of the plant (physical presents) as the optimal entry mode in African EV market. It requires the EV manufacturers a tire-free emission innovation technology in order to optimize the global sustainability initiative.

• 대한교통학회:학술대회논문집
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• 대한교통학회 2007년도 제57회 학술발표회논문집
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• pp.201-209
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• 2007

• 대한교통학회:학술대회논문집
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• 대한교통학회 2007년도 제57회 학술발표회논문집
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• pp.249-255
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• 2007

• 대한교통학회지
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• 제24권6호
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• pp.89-102
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• 2006

정적 기 종점 통행량을 가정함으로써 갖는 동적 시뮬레이션 모형의 현실 모사 능력의 한계를 극복하기 위하여 동적 기 종점 통행량 추정 모형을 개발하였다 동적 기 종점 통행량 추정은 통행자의 출발시간, 통행수단. 통행경로 선택 행태모형을 결합한 복합통행행태 수요시뮬레이션 모형을 이용하였다 본 연구에서 개발된 수요 시뮬레이션 모형과 기 개발된 공급 시뮬레이션 모형인 LiCROSiM-P를 결합하여 통합 시뮬레이션 모형을 구축하였다. 단속류/연속류가 공존하는 다경로 가로망에서 출발시간/수단선택/통행경로 선택모형은 AGtt(기 종점통행시간의 시뮬레이션 시간과 기대치의 차이 백분율)는 수렴하지 않고, 평균스케줄지체는 안정 상태로 수렴하는 것으로 나타났다. 통합 시뮬레이션 모형은 교통시설공급 변화와 통행자의 속성 변화에 따른 기 종점 통행량 변화 추정과 효과분석이 가능함을 모형의 적용을 통해 제시하였다. 따라서 통합시뮬레이션 모형은 수요관리정책, 교통시설변화, 교통정보제공 등이 가져오는 출발시간, 통행수단, 통행경로변화를 반영한 시스템의 효과분석이 가능하다

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.97-112
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• 1995

The purpose of this study was to evaluate the effect of wetting condition made by drying time on bonding of resin cement to dentin. Freshly extracted bovine teeth were grinded to expose flat dentin surfaces. After the exposed dentin surfaces were treated with pretreatment agents and water rinse, each wetting condition of dentin surfaces was made according to drying times and methods including slight blow bry for I-second by air syringe, blow dry for 20-second by air syringe, and 12-hour dry in desiccator respectively. and then, previously made composite resin specimens were bonded onto each conditioned dentin surface of the specimen using Panavia-21(Kuraray Co.), Bistite(Tokuso Co.), and Choice(use with All bond-2, Bisco Inc.) resin cement according as manufacturer's instruction. Bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured, cohesive failure rate was calculated, and fractured dentin surfaces and acrylic rod sides were examined under scanning electron microscope. The result were as follows ; In the group of bonding with Panavia-21 resin cement, higher tensile bond strength was seen in 12-hour dry group than in I-second and 20-second dry group(p<0.01). In the group of bonding with Bistite resin cement, higher tensile bond strength was seen in 1-second dry group than in 20-second and 12-hour dry group(p<0.01). In the group of bonding with Choice resin cement, no significant differences of bond strength under given drying time were seen. Cohesive failure rates derived from the groups of bonding with Panavia-21 and Choice resin cement were increased with the increase of tensile bond strength in each drying time. On SEM examination of fractured surface, adhesive failure mode with fractured resin tags was mostly seen in wet condition with I-second drying time in the group of bonding with Panavia-21 resin cement, mixed failure mode with shortened and fractured resin tag was seen in the group of bonding with Bistite resin cement, and regardless of drying time, and cohesive-adhesive mixed failure mode with fracture of 'Hollow' typed resin tags was mainly seen in the group of bonding with Choice resin cement.