• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.241-249
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• 2014

This paper presents a path planning algorithm of an autonomous vehicle (ADAM III) for collision avoidance in the presence of multiple obstacles. Under the requirements that a low-cost GPS is used and its computation should be completed with a sampling time of sub-second, heading angle estimation is proposed to improve performance degradation of its measurement and a hierarchical structure for path planning is used. Once it is decided that obstacle avoidance is necessary, the path planning consists in three steps: waypoint generation, trajectory candidate generation, and trajectory selection. While the waypoints and the corresponding trajectory candidates are generated based on position of obstacles, the final desired trajectory is determined with considerations of kinematic constraints as well as an optimal condition in a term of lateral deviation. Finally the proposed algorithm was validated experimentally through field tests and its demonstration was performed in Autonomous Vehicle Competition (AVC) 2013.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.302-305
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• 2007

During the CareBeijing campaign in September 2006, Imaging Differential Optical Absorption Spectroscopy (IDOAS) measurements were made over the city of Beijing, China using a spatial resolution of 146 pixels horizontally and 61 pixels vertically, each with a field of view of $0.133^{\circ}$ and $0.072^{\circ}$ in the horizontal and vertical directions, respectively. Using Fraunhofer reference spectra (FRS) for the evaluation of data for two consecutive days, the diurnal variation of $NO_2$ distributions was determined from data measured every single hour from 08:00 until 16:00 on September 9 and 10. Both days presented a fairly clear sky with high visibility. The setup allowed detailed images of the low surface $NO_2$ distribution over Beijing. Images with less than a 30-min temporal resolution showed variation of plume dispersal in both horizontal and vertical directions. An in-situ measurement was also conducted. Results from both instruments are interpreted by considering local emission sources and wind conditions.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.66-66
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.892-897
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• 2003

This study deals with the performance of a simplified test apparatus for measurement of sound insulation of panels. In order to investigate its performance, results from experiment and theory of the sound transmission loss for single and double panels are compared. Comparative results show that in evaluation of the sound insulation performance, the test apparatus has a cumbersome problem at the low frequency region, i.e. below 315 ㎐, presumably because of the poor diffuse sound field in the chambers. Meanwhile at the high frequency, it shows a considerable results comparable to the theoretical prediction. One of the objective of this study that compares measured results between a real reverberation chamber and a simplified test apparatus, by using a specimen of a sandwich panel. It shows qualitatively resonable agreement from which one can find a potential to provide a design tool.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.195-206
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• 1997

By this time, in order to measure baseline in a few minutes, we must have used expensive dual frequency receiver. Recently, low-priced single frequency receiver have taken place of dual frequency receiver at short base-line by advancement in software development, improvements in geodetic survey receiver system. In this study, according to the observation time and measurement interval, we analyzed differences of each components of baseline by field experiment and we propose the criterion for the minor control point surveying by single frequency GPS receiver.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.323-328
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• 2007

The residual stress in axial direction of the steel wires has been measured by using a method based on the combination of the focused ion beam(FIB) milling and digital image correlation(DIC) program. The residual stress is calculated from the measured displacement field before and after the introduction of a slot along the steel wires. The displacement is obtained by the digital correlation analysis of high-resolution scanning electron micrographs, while the slot is introduced by FIB milling with low energy beam. The experimental procedures are described and the feasibilities are demonstrated in steel wires fabricated with different conditions. It reveals that the tensile residual stress is formed in all steel wires and this is strongly influenced by the fabrication conditions.

• Journal of Magnetics
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• v.13 no.4
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• pp.173-176
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• 2008

In this study, a new kind of instrument for measuring the magnetic shielding effectiveness (MSE) was developed using a double yoke; one a magnetizing yoke and the other a sensing yoke. Using the developed instrument, the MSE could be measured for a steel sheet specimen in the ELF range, where the magnetic permeability contributes to the MSE at low frequencies and eddy currents contributes to the MSE high frequencies with < 0.1 dB reproducibility. The developed measuring method can be applied to quality control in a steel sheet company producing EMI/EMC shielding materials.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1203-1214
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• 2015

This paper deals with the experimental validation of the use of PVDF Patches for the assessment of spatial derivatives of displacement field. It focuses more exactly on the shear Force Identification by using Specific forms of PVDF patcHes (FISH) on beams. An overview of the theoretical approach is exposed. The principle is based on the use of the weak form of the equation of motion of the beam which allows the shear forces to be extracted at one edge of the sensor when this last has a specific form. The experimental validation is carried out with a cantilever steel beam, excited by a shaker at its free boundary. The validation consists in comparing the shear force measured by the designed sensor glued at the free edge and the directly measured force applied by the shaker. The sensor is made of two patches, called the "stiffness" patch and the "mass" patch. The use of both patches allows one to identify correctly the shear force on a large frequency domain. The use of only the stiffness patch is valid in the low frequency domain and has the advantage to have a frequency-independent gain that allows its use in real time.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.183-187
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• 2007

The detection and measurement of faint features in cometary image is generally troublesome due to the high value of the ratio of the brightness of the nucleus to the tail, the large size and low surface brightness of the coma and tail and the disturbing presence of field stars trails. The image processing is based on background removal by median filtering. Sample results are shown for the case study of comet 73P/Schwassmann-Wachmann 3.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.33-35
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• 1988

From the study of mechanism of electrical conduction of film which is made from Polyethylene Terephthalate at very high temperature which is larger than low electric field and glass transition point, we find that there is a extraordinary non ohmic region (I∝V$^n$, 0