• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.153-155
• /
• 2006

A major advantage of the area in and around Braunschweig is its concentration of major research institutes and small to large enterprises dealing with different modes of transportation. For many years, aviation has been a particular focus. The research institutes have aircraft and helicopters equipped especially for research projects, as well as other laboratory equipment, allowing simulation and testing of air traffic application both virtually and on real aircraft. In addition, with the Luftfahrtbundesamt (equivalent organization to FAA) and the Bundesstelle $f{\"{u}}r$ Flugunfalluntersuchung (equivalent to NTSB) both located at the Research Airport, it enables direct contact with two key air-traffic safety authorities. The institutes of DLR and the Technical University of Braunschweig are very active in rail transportation applications. Cooperation with the market leader in rail automation - Siemens Rail Automation, also located in Braunschweig - and with other companies in the Braunschweig region means that safety-critical road applications and mobility research is available due to the activities of a number of institutes. Cooperation with Volkswagen (VW) and other companies in the region ensure access to the market leaders' know-how in this sector. Current European activities within framework of the Galileo project offer particularly good opportunities for the Research Airport to leverage its expertise and position itself internationally as a specialist in safety-critical transport applications - the centre is an initiative of Niedersachsen and the Ministry of Economic Affairs, Labour and Transport Location and navigation plays a central role in all modes of transport - air, road and rail. The market is being revolutionized by the increasing integration of GNSS. The realization of the Galileo system will provide additional opportunities for the Research Airport: Galileo as a civil operated system offers service guarantees especially in the area of safety-critical applications in transportation. Notably standards, processes and authorizations related to the certification of safety-critical applications in the areas of air, road and rail transportation are still to be determined. GAUSS, located at the Research Airport Braunschweig, as an European centre of excellence for simulation, testing and certification of safety-critical applications can offer its expertise to validate the services guaranteed by the Galileo concessionaire.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1998.02a
• /
• pp.156-157
• /
• 1998

It is a diffcult and challenging pproblem to control the growth of eppitaxial films. Heteroeppitaxy is esppecially idfficult because of the lattice mismatch between sub-strate and depposited layers. This mismatch leads usually to a three dimensional(3D) island growth. But the use of surfactants such as As, Sb, and Bi can be beneficial in obtaining high quality heteroeppitaxial films. In this study medium energy ion scattering sppectroscoppy(MEIS) was used in order to reveal the growth mode of Ge on Si(001) and the strain of depposited film without and with dynamically supplied atomic hydrogen at the growth thempperature of 35$0^{\circ}C$. It was ppossible to control the growth mode from layer-by-layer followed by 3D island to layer-by-layer by controlling the hydrogen flux. In the absent of hydro-gen the film grows in the layer-by-layer mode within the critical thickness(about 3ML) and the 3D island formation is followed(Fig1). The 3D island formation is suppressed by introducing hydrogen resulting in layer-by-layer growth beyond the critical thickness(Fig2) We measured angular shift of blocking dipp in order to obtain the structural information on the thin films. In the ppressence of atomic hydrogen the blocking 야 is shifted toward higher scattering angle about 1。. That means the film is distorted tetragonally and strained therefore(Fig4) In other case the shift of blocking dipp at 3ML is almost same as pprevious case. But above the critical thickness the pposition of blocking dipp is similar to that of Si bulk(Fig3). It means the films is relaxed from the first layer. There is 4.2% lattice mismatch between Ge and Si. That mismatch results in about 2。 shift of blocking dipp. We measured about 1。 shift. This fact could be due to the intermixing of Ge and Si. This expperimental results are consistent with Vegard's law which says that the lattice constant of alloys is linear combination of the lattic constants of the ppure materials.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.1
• /
• pp.5-12
• /
• 2013

The critical velocity effect on railway trackbed means the amplification of vibration energy when the train running-speed and group velocity of ground surface wave are superimposed. It is called a pseudo-resonance phenomenon of time domain. In the past, it was not issued because the train speed was low and the ground group velocity was higher. But since the high-speed train is introduced, critical velocity reported causing a track irregularity. So far, theoretical analysis has been performed because of the complexity of formation process. However it requires reasonable consideration which is similar to actual track and trackbed conditions. In the present paper, finite element analysis to verify the critical velocity effect is performed considering each track structure and trackbed supporting stiffness. As a result, the deformation amplification caused by the critical velocity effect is verified to analyze each supporting stiffness and track system.

• Journal of Information Technology and Architecture
• /
• v.9 no.4
• /
• pp.443-453
• /
• 2012

In order to minimize the damage from system failures, systems over various fields are requested to contain the safety-critical features. In this paper, we deliver the considerable issues, especially, in the cyber physical systems that is recently used as a safety-critical system, as well as we propose the model driven architecture based on time as its the important factor. Based on meta-modeling approach, we introduce the time-based architecture which is associated with deadline, transition state, and threshold, and also we work out a design for this by using model driven architecture. We propose a realizable safety-critical architecture by means of showing failure handling components with safety transaction model from the meta-model. In the detailed models and the example, we design a basic safety processing state, a multiple safety processing state, and a compound safety processing state for completing the safety-critical system architecture.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.10
• /
• pp.1-8
• /
• 2002

C- V method is a means to determine the effective channel length for miniaturized MOSFET's. This method achieves L$_{eff}$ by extracting a unique channel length independent extrinsic overlap length($\Delta$L) at a critical gate bias point. In this paper, we conducted an experiment on two different C-V methods. L$_{eff}$ extracted from experiment is compared with L$_{eff}$ simulated from a two-dimensional (2-D) device simulator, and the accuracy of C-V method for L$_{eff}$ extraction is analyzed.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1158-1161
• /
• 2004

Shell shaped hollow carbon nanoparticles are synthesized in the oxygen-hydrogen diffusion flame with $C_{2}H_{2}$ as precursor when it is irradiated with $CO_{2}$ laser of certain power. Below this power of laser, we couldn't get any other but amorphous soot. This shell shaped hollow carbon nanoparticles shows outer wall of high degree of crystallinity with void space inside of itself. And size distribution of these nanoparticles is measured with TEM image analysis. Also the structural comparison between this carbon nanoparticle and soot is done by Raman and XRD measurement. These results show this carbon nanoparticles are of grapheme structure, which means it has good crystallinity when compared with soot.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.2
• /
• pp.144-150
• /
• 2000

In this paper, the formation of a corner cavity in the final stage of axisymmetric backward extrusion process is studied by means of upper bound analysis using kinematically admissible velocity. The quantitative relationships between corner cavity formation and process parameters are studied. And analytical results are compared with those of experiment to which plasticine is used. It is found that the analytical results agree well with experimental one. In addition, to restrict the formation of a corner cavity, driven container is applied to backward extrusion and the results are compared with those of FEM. The critical thickness of the bottom of the billet decreases with increase in reduction of area, and increases with decrease in friction. To prevent the formation of corner cavity, the concept of moving container was applied. Throughout this process, the occurrence of a corner cavity is delayed and forming limit area is enlarged.

• Journal of Navigation and Port Research
• /
• v.34 no.7
• /
• pp.559-566
• /
• 2010

The container port industry has been variously studied by many researchers, because the contemporary container transportation and container port industries play a pivotal role in globalization of the world economy. For container terminals, the productivity, affected by many factors, is an important target in measuring container terminal performance. Under this background, finding the critical factors affecting the productivity is necessary. Regression analysis can be used to identify which independent variables are related to the dependent variable, and explore the relationships of them. The aim of paper is to evaluate the factors affecting the productivity of Chinese major terminals by using a regression statistical analysis modeling approach, which is to establish the variable preprocessing model (VPM) and regression analysis model (RAM), by means of collecting the major Chinese container terminals data in the year of 2008.

• International Journal of Safety
• /
• v.6 no.2
• /
• pp.8-12
• /
• 2007

This study includes a case study among plastic process manufacturing companies, based on which, the currently used 4M method is applied in terms of machine, media, man, and management, to conduct quantitative risk evaluation, and thus to contribute to reducing human and material loss as well as preventing accidents in industrial fields. The result of this study is analyzed based on the 4M-risk assessment to find out the hazardous risk elements, and the quantitative evaluation made it predictable the value of risk(frequency $\times$ intensity) in such classified levels as serious risk, critical risk, and intolerable risk. Further, Among the businesses with hazardous risk elements and high frequency of industrial disaster, risk analysis was conducted for each process, and as a result, 38 cases among 76, including those of serious risk, critical risk, and intolerable risk, were improved, and the risk was reduced. Besides, it is thought that with the engineering approach with 4M-Risk Assessment, the attempt to improve safety level contributes to prevention of accidents.

• Structural Engineering and Mechanics
• /
• v.6 no.5
• /
• pp.555-569
• /
• 1998

The reliability of antenna tower designed for a n-year design wind speed is determined by considering the variability of the strength of the component members and of the mean wind speed. For obtaining the n-year design wind speed, maximum annual wind speed is assumed to follow Gumbel Type-1 distribution. Following this distribution of the wind speed, the mean and standard deviation of stresses in each component member are worked out. The variability of the strength of members is defined by means of the nominal strength and a coefficient of variation. The probability of failure of the critical members of tower is determined by the first order second moment method (FOSM) of reliability analysis. Using the above method, the reliability against allowable stress failure of the critical members as well as the system reliabilities for a 75 m tall antenna tower, designed for n-year design wind speed, are presented.