• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2003년도 하계학술대회 논문집
• /
• pp.112-112
• /
• 2003

• 한국자동차공학회논문집
• /
• 제22권1호
• /
• pp.117-125
• /
• 2014

The temperature distribution of steady state rolling tires with detailed tread blocks is numerically predicted using the three dimensional full patterned tire model. A three dimensional periodic patterned tire model is constructed by copying 1-sector mesh in the circumferential direction. Using the static tire contact analysis, the strain cycles during one revolution are approximated with the strains at Guassian points of the elements which are sector-wise repeated within the same circular ring of elements, by neglecting the tire rolling effect. Based upon the multi-axial fatigue theory, the maximum principal strain is used to represent the combined effect of six strain components on the hysteretic loss. In the following, the deformation due to the inflation and vertical load is calculated using ABAQUS. Then heat generation rate in each element is calculated using an in-house code. Lastly, temperature distribution is calculated using ABAQUS again. Through the numerical experiments, the validity of the proposed prediction method is examined by comparing with the experiment and the temperature distribution of a patterned tire model is compared with those of the main-grooved simple tire model.

• STI Policy Review
• /
• 제6권1호
• /
• pp.1-23
• /
• 2015

Based on the work of Anand et al. (2013) we measure inclusive income growth, which combines growth in gross domestic product (GDP) per capita and growth in the equity of the income distribution. Extending the work of Causa et al. (2014), we estimate a dynamic simultaneous structural equations model of GDP per capita and inclusive income on panel data for 63 countries over the 1990-2013 period. We estimate both equations in error correction form by difference GMM (generalized method of moments). Among the explanatory variables of the level and the distribution of GDP per capita we include R&D (research and development) expenditure per capita. In OECD countries we obtain a large positive effect of R&D on GDP. R&D is found to have a positive effect on the social mobility index but its impact on the income equity index at first decreases, then switches around to become slightly positive in the long run. In non- OECD countries, R&D is found to decrease inclusive income, mostly through a negative growth effect but also because of a slightly increasing income inequity effect.

• 항공우주시스템공학회지
• /
• 제10권1호
• /
• pp.51-58
• /
• 2016

In this paper, we present some results on No-failure accelerated life test of aerial vehicle for reliability demonstration. The design of general accelerated life test consists of the three phases: 1) Estimating normal life test time of a single product from Weibull distribution model; 2) Determining the acceleration factor (AF) by utilizing the relation between the life of mechanical components and the applied torque; 3) Calculating the accelerated life test time, which comes from dividing the estimated normal life test time into AF. Then, we applied the calculated life test time to the real reliability test of the flap actuating system, while considering the requirement specification for mechanical components and operating environment of the actuation system. Real experimental processes and results are presented to validate the theory.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 E
• /
• pp.2274-2276
• /
• 1999

In this work, temperature rise and eddy current distribution on the enclosure and conductor of 3 pole gas insulated switchgear were investigated using analytical and experimental measures. The design of the diameters of the conductors and the enclosures of a meal clad gas insulated switchgear is primarily based on the insulation requirements. It is very difficult problem to predict the temperature rise of enclosed switchgear due to the complexity of the phenomena of heat transfer and existence of eddy current loss. To overcome this situations, we focused on the eddy current distribution on the enclosure of switchgear caused by high current 3 pole conductor as a fundamental basis. The experimental results about temperature distribution of 3 pole gas insulated switchgear were reported and measurements are compared with predictions of three-dimensional thermal model for eddy current analysis. As a result, three dimensional numerical analysis found to be in close relationship with experimental results and thermal model is efficient to predict the abnormal temperature rise in switchgear.

• 전자공학회논문지CI
• /
• 제47권4호
• /
• pp.118-124
• /
• 2010

본 논문에서는 상황별 RFID(무선주파수식별) 물류 적재 시뮬레이터를 구현하였다. 이를 위하여 RFID의 적용 및 인식률에 영향을 줄 수 있는 환경요소들을 모델링하여 인식률 실험을 체계적으로 수행할 수 있도록 하였다. 실제로 물류 현장에 적용시켰을 때 보다 적은 시간과 비용으로 상황별 최적의 RFID 물류 적재 방법을 찾아 개선한 사례를 제시한다. 물류 현장에서 RFID 인식률을 높이기 위해 본 시뮬레이터를 사용하여 RFID 인식 실험데이터를 축적하였다. 이를 통해 본 논문에서 제안된 시뮬레이터가 시행착오를 줄이고 효과적으로 최적화된 RFID 물류 적용 안을 찾아낼 수 있다는 것을 실험치를 기준으로 증명 하였다.

• 한국응용과학기술학회지
• /
• 제30권1호
• /
• pp.35-48
• /
• 2013

바이오디젤은 식물성유지, 동물성유지 그리고 폐식용유를 전이에스테르화 반응을 시켜 만들어진 것으로 경유를 대체할 수 있는 연료이다. 본 연구에서는 다양한 원료의 식물성유지 (대두유, 폐식용유, 유채유, 면실유, 팜유)로부터 얻어진 바이오디젤의 연료 특성을 알아보았다. 다양한 식물성유지 원료로부터 얻어진 바이오디젤은 지방산메틸에스테르 함량, 동점도, 인화점, 필터막힘점, 글리세린 함량을 분석하였다. 바이오디젤의 품질기준과 시험방법은 한국 표준과 유럽 표준인 EN14214에 따라 시험하였다. 대두유, 폐식용유, 유채유, 면실유 바이오디젤은 불포화지방산이 많이 포함되어 있는 반면에 팜유 바이오디젤은 포화지방산이 많이 함유되어 있다. 저온특성, 동점도, 산화안정도와 같은 바이오디젤의 연료 특성은 지방산메틸에스테르의 구성 성분과 관련이 깊다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.201_202
• /
• 2009

This paper presents a design methodology of a distribution transformer with condition monitoring sensors and its data processing unit. The proposed distribution transformer includes various type of condition monitoring sensors such as load current/voltage, temperature and heat aging of insulating oil. The data processing unit is installed at the distribution transformer site. It integrates sensed data and transmits these to a central server system. The proposed distribution transformer and its data processing unit will help an on-line condition monitoring system for distribution transformers.

• 기술혁신연구
• /
• 제22권1호
• /
• pp.1-22
• /
• 2014

R&D 투자는 투입 시점과 산출 시점 사이에 시차(time lag)가 존재한다. 따라서 기업의 R&D 투자와 성과와의 관계를 분석할 때 R&D 투입의 시차효과를 정확히 반영하지 않을 경우 분석에 심각한 오류가 발생할 수 있기 때문에 본 연구는 기업 R&D 투자의 시차 효과의 추정을 목적으로 한다. 시차분포모형의 하나인 Almon 모형을 사용하여 기업의 R&D 투자의 투입 시점과 산출 시점 사이의 시차를 측정하였다. 이를 위해 2002년부터 2009년까지의 기업 패널 데이터를 구축하였다. R&D 투자는 기업의 R&D 투자 금액으로, R&D 성과는 특허 출원 건수로 정의하여 분석을 실시하였고 '투자-산출' 프로세스에 소요되는 시차의 길이를 추정하였다. 분석 결과 전체 기술 영역에서 R&D 투자와 특허 출원 사이의 시차는 1~2년으로 분석되었다. 화학, 금속 및 금속 가공, 전기 및 전자, 정밀 과학, 기계 제조의 다섯 개 산업군에 대해 각각 시차의 길이를 추정하였으며 산업군별로 추정된 시차의 길이에 차이가 존재하였다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권8호
• /
• pp.69-76
• /
• 2020

The study examines lagged economic effects of research and development (R&D) investment on the market value of manufacturing firms listed on the Shanghai Stock Exchange or the Shenzhen Stock Exchange in China. This study applies panel data analysis methods to address the following issues: 1) There might be an adjustment lag in the impact of R&D investment on corporate market value, and 2) Unobserved firm effects must be taken into account. The balanced panel data includes a total of 1,462 observations with 34 cross-sections of manufacturing firms listed on Chinese stock markets and with 27 time-specific quarterly periods from 2007 to 2017. The results indicate that the R&D investment of Chinese manufacturing firms tends to yield favorable market value of the firm with some adjustments to time. The results show that R&D investment exhibits a strong positive impact on their market value of manufacturing firms in Chinese stock markets. Moreover, R&D investment has a positive time-lag effect on the market value of the firm. Interestingly, the R&D investment of Chinese manufacturing firms generate a relatively constant positive effect on their market value, supporting the notion that the corresponding returns of R&D investment for such firms yield lagged but added market values.