• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5731-5754
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• 2019

In this paper, we redesign, implement, and evaluate ShareSafe (Based on SecGraph), an open-source secure graph data sharing/publishing platform. Within ShareSafe, we propose De-anonymization Quantification Module and Recommendation Module. Besides, we model the attackers' background knowledge and evaluate the relation between graph data privacy and the structure of the graph. To the best of our knowledge, ShareSafe is the first platform that enables users to perform data perturbation, utility evaluation, De-A evaluation, and Privacy Quantification. Leveraging ShareSafe, we conduct a more comprehensive and advanced utility and privacy evaluation. The results demonstrate that (1) The risk of privacy leakage of anonymized graph increases with the attackers' background knowledge. (2) For a successful de-anonymization attack, the seed mapping, even relatively small, plays a much more important role than the auxiliary graph. (3) The structure of graph has a fundamental and significant effect on the utility and privacy of the graph. (4) There is no optimal anonymization/de-anonymization algorithm. For different environment, the performance of each algorithm varies from each other.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.31-39
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• 2011

The facial recognition algorithms using Gabor wavelet based face graph produce very good performance while they have some weakness such as a large amount of computation and an irregular result depend on initial location. We proposed a fully automatic facial recognition algorithm using a Gabor feature based geometric deformable face graph matching. The initial location and size of a face graph can be selected using Adaboost detection results for speed-up. To find the best face graph with the face model graph by updating the size and location of the graph, the geometric transformable parameters are defined. The best parameters for an optimal face graph are derived using an optimization technique. The simulation results show that the proposed algorithm can produce very good performance with recognition rate 96.7% and recognition speed 0.26 sec for FERET database.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.28-34
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• 2006

Laboratory column tests using $Cl^-$ tracer were conducted to study the correlation of soil particle distribution and hydrodynamic dispersion mechanism with three kinds of ununiformed soil samples, in which the ratio of gravel and sand versus silt and clay is 24.5 for S-1 soil, 4.48 for S-2 soil, and 0.4 for S-3 soil. Chloride breakthrough curves with time were fitted with gaussian functions. The relative concentrations of chloride were converged to 1.0 after 0.7 hours for S-1, 6.3 hours for S-2, and 389 hours for S-3. Average linear velocity, longitudinal dispersion coefficient, and longitudinal dispersivity were calculated by chloride breakthrough curves. Longitudinal dispersion coefficients were $1.20{\times}10^{-4}\;m^2/sec$ for S-1, $8.87{\times}10^{-7}\;m^2/sec$ for S-2, and $1.94{\times}10^{-9}\;m^2/sec$ for S-3. Peclet numbers calculated by the molecular diffusion coefficient of chloride and the mean grain diameters of soils were $2.59{\times}10^2$ for S-1, $6.27{\times}10^0$ for S-2, and $1.35{\times}10^{-4}$ for S-3. Mechanical dispersion was dominant for the hydrodynamic dispersion mechanism of S-1. Both mechanical dispersion and molecular diffusion were dominant for the hydrodynamic dispersion mechanism of S-2, but mechanical dispersion was ascendant over molecular diffusion. Hydrodynamic dispersion in S-3 was occurred mainly by molecular diffusion. When plotting three soils on the graph of $D_L/D_m$ versus Peclet number produced by Bijeljic and Blunt (2006), the values of $D_L/D_m$ for S-1 and S-2 were more than 2.0 order compared to their graph. S-3 was not plotted on their graph because the Peclet number was as small as $1.35{\times}10^{-4}$.

• Fire Science and Engineering
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• v.15 no.3
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• pp.44-48
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• 2001

In this study, we analyzed the $CH_4$and $C_4$$H_{10}$ sensitivity measurement and voltage variation using catalytic type gas sensor characteristics in catalytic combustion type gas detecter sensors. Gas detector shall operate as intended when exposed for 24 hours to air having a relative humidity of 65 percent at a temperature of $20^{\circ}c$ and humidity of 85 percent at a temperature of $40^{\circ}c$. The gas detecter sensors are to be subjected to operation for 210 days in an area that has been determined to be equivalent to a typical residential atmosphere with an air velocity of 50 cm/sec. The source of energy for a gas detector sensors employing a supplementary basic circuit is energized from a seperate source of supply direct applied voltage 2.1V, 2.2V, 2.3V. As a result, it was confirmed that the relative humidity and temperature by regression each analysis, compared to the isobutane characteristic graph and methane characteristic graph by a relative humidity of 65% and 85% at a temperature($20^{\circ}c$, $40^{\circ}c$) show a similar linear pattern on the whore.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.773-777
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• 2002

In this study, we analyzed the LPG and LNG sensitivity measurement and voltage variation using catalytic type gas sensor characteristics in catalytic combustion type gas detecter sensors. gas detector shall operate as intended when exposed for 24 hours to air having a relative humidity of 0~85 percent at a temperature of $20[{\mu}m]$ and humidity of 45 percent at a temperature of $-10{\sim}40[^{\circ}C]$ the gas detecter sensors are to be subjected to operation for 210 days in an area that has been detemined to be equivalent to a typical residential atmosphere with an air velocity of 50 [cm/sec]. The source of energy for a gas detector sensors employing a supplementary basic circuit is energized from a separate source of supply direct applied voltage 2.1[V], 2.2[V], 2.3[V]. As a result, it was confirmed that the relative humidity and temperature by regression each analysis, compared to the LPG characteristic graph and methane characteristics graph by a relative humidity of 0 ~ 85 [%] at a temperature range of $-10{\sim}40[^{\circ}C]$ show a similar linear pattern on the whore.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.23-26
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• 1997

In exposuring x-rays, we can adjust three variables of kVp, mA and sec. The kVp is one of main factors affecting x-ray quality -peneterability. And miliampere-seconds is directly proportional to x-ray quantity. In this paper, we detected voltage variation of CdS, II-VI group semiconductor compounds, by kVp as the fundamental experiments of designing x-ray dosimeter. We exposured x-ray on the material from 40 to 100 kVp by increasing 2kVp using Shimadazu TH-500-125 Radio-Tex cx-s x-ray machine. We fixed miliampere -seconds to 100mA and 0.2 sec. After acquiring the raw data, we plotted the graph of kVp and voltage variation and figured slope value of 0.093 by regression. The standard deviation of voltage to kVp was 0.22. For the future study, the mAs variation study will be needed to investigate the connections between kVp and mAs in order to design x-ray dosimeter.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.466-471
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• 1996

In order to investigate the compression characteristics on the some vegetables-cucumber, garlic, ginger, potato, and radish-compression force, distance, and time were measured with a Struct-O-Graph and correlations between them were investigated. Force-distance and distance-time curves were showed simply and reflection points were showed rarely. The time to rupture point was long of 11.7sec at the compression speed of 60mm/min and of 6.16sec at the compression speed of 120mm/min in potato, and short of 9.65, 4.55sec at the different compression speed in garlic, respectively. The rupture force was large of 16.64~20.00N at the different compression speed in potato and radish, and the sample at rupture point was showed crushing behavior under probe. These phenomena were suggested because compression strength of sample was different. In the result of regression analysis for force-time and distance-time to the rupture point, the correlation coefficients were above 0.96, and difference of among samples was small. The slopes of force-time were large of 1.772~3.385 in cucumber and small of 1.743~3.338 in potato, and the slopes of distance-time were obtained with reverse results.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.11-14
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• 2000

In this paper, we propose a fast and practical head pose estimation scheme fur eye-head controlled human computer interface with non-constrained background. The method we propose uses complete graph matching from thresholded images and the two blocks showing the greatest similarity are selected as eyes, we also locate mouth and nostrils in turn using the eye location information and size information. The average computing time of the image(360*240) is within 0.2(sec) and we employ template matching method using angles between facial features for head pose estimation. It has been tested on several sequential facial images with different illuminating conditions and varied head poses, It returned quite a satisfactory performance in both speed and accuracy.

• Korean Journal of Remote Sensing
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• v.33 no.6_3
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• pp.1215-1221
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• 2017

SeNtinel's Application Platform (SNAP) is an open source software developed by the European Space Agency and consists of several toolboxes that process data from Sentinel satellite series, including SAR (Synthetic Aperture Radar) and optical satellites. Among them, S1TBX (Sentinel-1 ToolBoX)is mainly used to process Sentinel-1A/BSAR images and interferometric techniques. It provides flowchart processing method such as Graph Builder, and has convenient functions including automatic downloading of DEM (Digital Elevation Model) and image mosaicking. Therefore, if computer memory is sufficient, InSAR (Interferometric SAR) and DInSAR (Differential InSAR) perform smoothly and are widely used recently in the world through rapid upgrades. S1TBX also includes existing SAR data processing functions, and since version 5, the processing capability of KOMPSAT-5 has been added. This paper shows an example of processing the interference technique of KOMPSAT-5 SAR image using S1TBX of SNAP. In the open mine of Tavan Tolgoi in Mongolia, the difference between DEM obtained in KOMPSAT-5 in 2015 and SRTM 1sec DEM obtained in 2000 was analyzed. It was found that the maximum depth of 130 meters was excavated and the height of the accumulated ore is over 70 meters during 15 years. Tidal and topographic InSAR signals were observed in the glacier area near Jangbogo Antarctic Research Station, but SNAP was not able to treat it due to orbit error and DEM error. In addition, several DInSAR images were made in the Iraqi desert region, but many lines appearing in systematic errors were found on coherence images. Stacking for StaMPS application was not possible due to orbit error or program bug. It is expected that SNAP can resolve the problem owing to a surge in users and a very fast upgrade of the software.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.407-411
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• 1999

Studies have been carried out on the fabrication of PPy/GC and PPy/Pt electrode modified with polypyrrole film and determination of Cr(VI) by using 3-electrode system with modified electrodes. Modified electrodes were able to easily fabricated by cyclic voltammetry scanned from +1.0V to -1.0V(vs. Ag/AgCl) at 50 mV/sec. Film thickness could be controlled at same condition by the number of cycling up to 26 times. Reduction behaviour of Cr(VI) at PPy/GC electrode could be seen at wide potential ranges from +0.6V to -0.5V(vs. Ag/AgCl), and maximum reduction peak potential of the ion was observed at -0.25V(vs.Ag/AgCl). Calibration graph at its potential was linear from 0.1 ppm to 80.O ppm. Slope factor and relative coefficient were 1.75 mA/ppm and 0.998, respectively. Reduction behaviour of Cr(VI) at PPy/Pt electrode was similar to PPy/GC electrode, Calibration graph was linear from l.0 ppm to 60.0 ppm. Slope factor and relative coefficient were 0.5mA/ppm and 0.923, respectively. But PPy/GC modified electrode had about 3 times higher sensitivity than PPy/Pt modified electrode. Reduction behaviour of Cu(II), As(IlI), Pb(II), and Cd(II) couldn't be seen at PPy/GC electrode,Its metals had not lnterfered with Cr (VI) determination.