• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.921-926
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• 2006

The Presence of a line-of-sight(LoS) blockage can degrade the UWB positioning accuracy for two reasons. Firstly, it makes estimation of the time of arrival(ToA) of the direct path signal difficult by complicating the multipath structure of the propagation channel. Secondly, the higher dielectric constant of the LoS blocking material than that of free space introduces excess propagation delay which will bias the range estimation. In this paper, methods based on ray tracing to reduce the ranging error resulting from the second reason are Posed. We take two different approaches; a statistical approach and a map-aided method. In the statistical approach, we establish a conditional distribution of the excess propagation delay caused by LoS blockages using a ray tracing technique. The lo6wer bound of the ranging performance based on this model is estimated. Ine ray tracing method is also used for the map-aided ToA positioning approach. UWB propagation measurement data taken in an office environment is used to examine the performance of this method.

• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.526-531
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• 2012

During our on-going studies to identify bioactive compounds in medicinal herbs, we found that saucerneol F (SF), a naturally occurring sesquilignan isolated from Saururus chinensis (S. chinensis), showed in vitro anti-inflammatory activity. In this study, we examined the effects of SF on the generation of 5-lipoxygenase (5-LO) dependent leukotriene $C_4$ ($LTC_4$), cyclooxygenase-2 (COX-2) dependent prostaglandin $D_2$ ($PGD_2$), and on phospholipase $C{\gamma}1$ ($PLC{\gamma}1$)-mediated degranulation in SCF-induced mouse bone marrow-derived mast cells (BMMCs). SF inhibited eicosanoid ($PGD_2$ and $LTC_4$) generation and degranulation dose-dependently. To identify the molecular mechanisms underlying the inhibition of eicosanoid generation and degranulation by SF, we examined the effects of SF on the phosphorylation of $PLC{\gamma}1$, intracellular $Ca^{2+}$ influx, the translocation of cytosolic phospholipase $A_2$ ($cPLA_2$) and 5-LO, and on the phosphorylation of MAP kinases (MAPKs). SF was found to reduce intracellular $Ca^{2+}$ influx by inhibiting $PLC{\gamma}1$ phosphorylation and suppressing the nuclear translocations of $cPLA_2$ and 5-LO via the phosphorylations of MAPKs, including extracellular signal-regulated protein kinase-1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38. Taken together, these results suggest that SF may be useful for regulating mast cell-mediated inflammatory responses by inhibiting degranulation and eicosanoid generation.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.641-646
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• 2008

In this research, recovery of high quality organics from excess activated sludge and its potential as a external carbon sources for BNR process was studied. By simultaneous treatment of alkali and ozone, TSS concentration was reduced by 32%, and RBDCOD fraction was increased by 76.2%, and major constitute of produced organic were acetic acid and propionic acid. Also, nitrogen and phosphorus were greatly solubilized. However, because acid-hydrolyzable phosphorus(AHP) was major part of solubilized phosphorus, $NH_4{^+}-N$ and $PO_4{^3}-P$ concentration were insufficient for effective formation of crystal like as MAP(Magnesium Ammonium Phosphate) and hydroxyapatite. By placing BPR reactor before alkali-ozone treatment reactor, $PO_4{^3}-P$ concentration in pretreated sludge was increased by 1.8 times, and improved potential of phosphorus recovery by crystallization. In experiment of crystallization, hydroxyapatite formation was more easily applied than MAP. By hydroxyapatite formation, $SCOD/PO_4-P$ ratio was greatly increased from 32.7 at control to 141.9 at $Ca^{2+}/PO{_4}^{3-}-P$ mole ratio of 2.4. The results based on this study indicated that the proposed system configuration has potential to reduce the excess sludge production, to recover phosphorus in usable forms as well as utilize organics as a external carbon source in BNR process.

• Journal of Digital Contents Society
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• v.11 no.1
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• pp.73-78
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• 2010

This study attempted to examine whether the propeller diffusion weighted image method may remove magnetic susceptibility artifacts caused by metallic materials. A comparison of occurrence rates of magnetic susceptibility artifacts in the four regions, both temporal lobes, pons, and orbit, between b = 0 and b = 1,000 s/mm2 images was made after obtaining echo-planar diffusion weighted image, propeller diffusion weighted image, and ADC map images, respectively, from a total of 20 patients who had MRI shots taken of their brain and were found to be with retained metallic foreign bodies within their teeth using a 3.0T MR scanner. In the case of echo-planar diffusion weighted image technique, the presence of metallic materials may bring in some limits on accurate diagnosis due to magnetic susceptibility artifacts, while the propeller diffusion weighted image technique where magnetic susceptibility artifacts decrease is expected to be more useful in ensuring accurate diagnosis in the clinical context.

• Journal of the Korea Society for Simulation
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• v.16 no.3
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• pp.57-63
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• 2007

In real time rendering of fetus the empty space leaping while traversing a ray is most frequently used accelerating technique. The main idea is to skip empty voxel samples which do not contribute the result image and it speeds up the rendering time by avoiding sampling data while traversing a ray in the empty region, saving a substantial number of interpolations. Calculating the distance from the nearest object boundary for every yokel can reduce the sampling operation. Among widely-well-known distance maps, those estimates the true distance, such as euclidean distance, takes a long time to compute because of the complicated floating-point operations, and others which uses approximated distance functions, such as city-block and chessboard, provides faster computation time but sampling error may can occur. In this paper, therefore, we analyze the characteristics of several distance maps and compare the number of samples and rendering time. And we aim to suggest the most appropriate distance map for rendering of fetus in ultrasound image.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.1-7
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• 2012

Generally, correction methods for faded images use illuminant estimation algorithms, such as the gray world assumption and white patch Retinex methods, as the phenomenon of color fading is regarded as an illuminant effect. However, this induces inaccurate faded color correction, as images fade at different rates according to the ink property, temperature, humidity, and illuminant. Therefore, this paper presents a color correction method for faded images using classification in LCybCrg color space. The input faded image is first separated according to the chromaticity based on LCybCrg opponent color space. The faded color correction is then performed based on the gray world assumption in RGB color space. Thereafter, weights calculated from CybCrg values are applied to reduce contour artifacts. As a result, the proposed method provides better color correction for faded images than previous methods.

• The Transactions of the Korea Information Processing Society
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• v.1 no.3
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• pp.279-289
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• 1994

A Geographic Database System is a database system which supports map-formed output and allows users to store, retrieve, manage and analyze spatial and aspatial data. Because of large data amount, takes too much time to input spatial data into a Geographic Database System and too much storage. Therefore, an efficient spatial data collecting system is highly required for a Geographic Database System to reduce the input processing time and to use the storage efficiently. In this paper, we analyze conventional vectorizing methods and suggest a different approach. Our approach vectorizes specific geographic data when the users input its aspatial data, instead of vectorizing all the map data. And also, we propose optimized vector data format using tag bit to use the storage that collected data efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4C
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• pp.277-282
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• 2012

In this paper, we present a real-time eye contact system for realistic telepresence using a Kinect depth camera. In order to generate the eye contact image, we capture a pair of color and depth video. Then, the foreground single user is separated from the background. Since the raw depth data includes several types of noises, we perform a joint bilateral filtering method. We apply the discontinuity-adaptive depth filter to the filtered depth map to reduce the disocclusion area. From the color image and the preprocessed depth map, we construct a user mesh model at the virtual viewpoint. The entire system is implemented through GPU-based parallel programming for real-time processing. Experimental results have shown that the proposed eye contact system is efficient in realizing eye contact, providing the realistic telepresence.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.583-590
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• 2008

In construction work's design process, we must carry out a topographical survey for construction reserved land and to the basis of this, production of profile is indispensable factor for the purpose of every construction work such as road, rail way, canal and etc. From this research, the production of profile about construction reserved land, using topographical information of digital topographical map produced by NGIS project, construct precision 3D terrain model and from this, propose plans for utilizing by producing automatic profile. With the aim of this, extract every layers of main facilities and altitude from digital topographical map and while producing 3D terrain model by using this, we product automatic profile from precision 3D terrain model. And we was carried out to check whether the automatic produced profile's accuracy could be accepted at actual estimation by mutual analysis. It is considered that the result of the research could be suggested as a new techniques concept which can reduce the designing period and expenses and increase the efficiency of affair in the design process for the construction.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.195-202
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• 2009

As the generation and application of spatial information is gradually expanded not only in traditional surveying fields but also a CNS and an ITS recently. The Accuracy and the newest of data grow to be an important element. But digital map is updated with system based tile. So, it is hard to get the newest of data and to be satisfied with user requirements. In this study, management system is developed to manage feature change efficiently using bid informations from NaraJangter which service the bid informations. A construction works with change possibility of feature from bid informations are classified and are made DB. And the DB is used as the feature change forecast informations. Also, It is converted from bid information of text form to positioning informations connected to spatial information data. If this system is made successfully, this system contributes to reduce the cost for the update of digital map and to take the newest date of spatial informations.