• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.167-272
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• 1998

The fluorine doped silicon oxide (SiOF) intermetal dielectric (IMD) films havc been of interest due to their lower dielectric constant and compatibility with existing process tools. However, instability issues related to hond and increasing dielectric constant due to water absorption when the SiOF film was exposured to atmospheric ambient. Therefore, the purpose nf this research is to study the effect of post oxygen plasma treatment on the resistance of nioisture absorption and reliability of SiOF film. Improvement of moisture ahsorption resistance of SiOF film is due to the forming of thin $SiO_2$ layer at the SiOF film surface. It is thought that the main effect of the improvement of moisture absorption resistance was densification of the top layer and reduction in the numher of Si-F honds that tend to associate with OH honds. However, the dielectric constant was inucased when plasma treatment time is above 5 min. In this study, therefore, it is thought that the proper plasma treatment time is 3 min when plasma treatment condition is 700 W of microwave power, 3 mTorr of process pressure and $300^{\circ}C$ of substrate temperature.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.411-419
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• 2013

Research on developing algorithms for building modeling such as extracting outlines of the buildings and segmenting patches of the roofs using aerial images or LiDAR data are active. However, utilizing information from the building model is not well implemented yet. This study aims to propose a scheme for search identical or similar shape of buildings by utilizing graph topology pattern matching under the assumptions: (1) Buildings were modeled beforehand using imagery or LiDAR data, or (2) 3D building data from digital maps are available. Side walls, segmented roofs and footprints were represented as nodes, and relationships among the nodes were defined using graph topology. Topology graph database was generated and pattern matching was performed with buildings of various shapes. The results show that efficiency of the proposed method in terms of reliability of matching and database structure. In addition, flexibility in the search was achieved by altering conditions for the pattern matching. Furthermore, topology graph representation could be used as scale and rotation invariant shape descriptor.

• Journal of KIISE:Software and Applications
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• v.37 no.4
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• pp.305-310
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• 2010

In this paper, we propose a heuristic algorithm for motion correspondence based on a point series similarity. A point series is a sequence of points which are sorted in the ascending order of their x-coordinate values. The proposed algorithm clusters the points of a previous frame based on their local adjacency. For each group, we construct several potential point series by permuting the points in it, each of which is compared to the point series of the following frame in order to match the set of points through their similarity based on a proximity constraint. The longest common subsequence between two point series is used as global information to resolve the local ambiguity. Experimental results show an accuracy of more than 90% on two image sequences from the PETS 2009 and the CAVIAR data sets.

• Nuclear Engineering and Technology
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• v.2 no.3
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• pp.163-178
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• 1970

Deformation modes at room temperature and the interaction between slip lines and ${\gamma}$' precipitate particles in heat treated Rene 41 were studied by means of replica techniques in an electron microscope. The alloy had been deformed by compression after aging for times up to 9300 hr at 76$0^{\circ}C$ and 87$0^{\circ}C$. The slip structure observed was similar to that of o brass, i.e., consisting of single slip lines occurred on the｛111｝<110> system. The slip structure was also correlated with aging conditions. Slip lines appeared to pass through ${\gamma}$' particles, shearing them with the matrix even after a prolonged heat treatment. It was concluded on the basis of comparison with previously published data that ${\gamma}$' particles remain at least partially coherent with the matrix even in a greatly overaged condition.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.9-14
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• 2013

In this paper, we propose a low complexity bilateral search SIC for OFDM in fast time-varying channels. Due to the possibility of error propagation in SIC, symbol detection ordering within the block of symbols has a significant effect on the overall performance. In this paper, the first symbol to be detected is determined based on CSEP values, and then the next symbol to be detected is selected according to the updated CSEP while bilaterally searching from the boundary of the detected symbol group. Through computer simulations, we show that the proposed method has performance improvements with almost the same computation complexity over the conventional methods in the high SNR region. It has a performance approaching the MFB, known as the performance upper bound, within 2dB at the BER of $10^{-5}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.912-918
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• 2014

In this paper, a VHF band multi channel phase discriminator for direction finding equipment using tripple baseline interferometer technique is proposed. In order to measure simultaneously phase difference between IF(Intermediate Frequency) signals of the direction finding equipment, phase discriminator was designed to have parallel structure with multi channel, the phase correlator of phase discriminator was designed with I, Q mixer for reducing number of components. And digital LUT(Look Up Table) was applied for compensating error of phase discriminator due to phase unbalance of RF components. The measured phase accuracy of fabricated phase discriminator was 2 degree RMS(Root Mean Square) at 30 dB SNR condition, which is superior to the phase accuracy of conventional product.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.67-75
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• 1998

This paper examined the geometrical variables of microstrip to control the characteristic impedance of MCM interconnect and also with respect to the practical requirements, evaluated the critical lengths for attenuation, propagation delay, and crosstalk at 500 MHz frequency compared to at 50 MHz frequency. With the illustration of each MCM-L and MCM-D interconnect having 50 characteristic impedance, it was revealed that the most important geometrical variables to control the characteristic impedance of microstrip are eventually dielectric thickness and line width. In particular, the dielectric thickness of MCM-D interconnect must be controlled with tolerance below 2 m. It is clear that the attenuation does not give rise to signal distortion in the range of up to 500MHz frequency for both MCM-L and MCM-D interconnects. However, the propagation delay is so significant that both MCM-L and MCM-D interconnects should be matched with load at the 500 MHz frequency. For the MCM-D interconnect, the crosstalk voltage would not be high to generate the wrong signal on the neighboring line at 500 MHz frequency, but the MCM-L interconnect could not be used due to severe crosstalk. Eventually, it is clear that the transmission line behavior must be studied for the design of MCM substrate at the 500 MHz frequency.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.99-109
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• 2016

This paper presents a method for generating spatiotemporal images to detect the leukocyte motions in a microvessel. By using the constraint that the leukocytes move along the contour line of a blood vessel wall, the method detects leukocyte motions and then generates spatiotemporal images. the translational motion by a movement in vivo is removed first by the template matching method. Next, a blood vessel region is detected by the automatic threshold selection method to binarize the temporal variance image, then a blood vessel wall's contour is expressed by B-spline function. With the detected blood vessel wall's contour as an initial curve, the plasma layer of the best accurate position is determined to be the spatial axis by snake. Finally, the spatiotemporal images are generated. The experimental results show the spatiotemporal images are generated effectively through the comparison of each step of three image sequences.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.62-71
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• 1995

In the numerical analysis of incompressible unsteady Navier-stokes equation, large time is required for solving the pressure Poisson equation of the elliptic type at each time step. In this paper, a numerical analysis by the direct method is carried out to solve the pressure Poisson equation and the computing time is analyzed as mesh size increases. The pressure Poisson equation can be transformed to the boundary value problem by the Green theorem. The computing time for the convolution type of the domain integral can be reduced by using F.F.T. and the computing time in the direct method depends entirely on obtaining the solution of the boundary value problem. The numerical analysis on the known solutions is carried out and compared for the verification of the direct method. And the numerical analysis on the body boundary and domain decomposition problem are carried out with the computing time less than O($n^{3}$) in the (n.n) mesh.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.5
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• pp.451-457
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• 2010

In the present study, the influences of grains and precipitates of microstructural evolution on the ultrasonic nonlinearity have been experimentally investigated. The prior-austenite grain and precipitate size are controlled by the variation in austenitizing and tempering conditions in reactor pressure vessel materials of nuclear power plant, SA508 Gr.3 low alloys. The ultrasonic nonlinearity was found to have strong correlations with grains and precipitates since the ultrasonic nonlinear parameter $\beta$ shows decrease trend with coarsening of grains and precipitates. Although the prior-austenite grain size increased, the $\beta$ changed little due to the effects of subgrains, packets and laths. For the preciptate effects, the $\beta$ decreased sharply due to decrease in $Mo_2C$ causing the coherency stain in addition to the precipitate size. The results in this study may provide a potential for characterizing the microstructural evolution, grains and precipitates, by measuring the ultrasonic nonlinearity.