• Journal of the Society of Cosmetic Scientists of Korea
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• 제34권2호
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• pp.109-115
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• 2008

The comparative molecular field analyses(CoMFA) models between the substituents with changing groups($R_1{\sim}R_4$) of $3{\beta}$-hydroxy-12-oleanen-28-oic acid derivatives as substrate molecule and their inhibitory activities($pI_{50}$) against protein tyrosine phosphatase(PTP)-1B were derived and discussed quantitatively. The optimized CoMFA F1 model have best predictability and fitness($r^2_{cv.}=0.654$ and $r^2_{ncv.}=0.995$). The order of contribution ratio (%) with CoMFA fields on the inhibitory activities was a steric field(53.0%), electrostatic field(36.2%) and hydrophobic field(10.8%). From the analytical results of CoMFA contour maps, the inhibitory activities were dependent on the R4 group in substrate molecules. Particularly, the new active compounds(P1 & P2) with the inhibitory activity against melanin synthesis were expected.

• Journal of Advanced Navigation Technology
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• 제17권1호
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• pp.115-122
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• 2013

Disease diagnostics based on medical imaging is getting popularity day by day. Presence of the atherosclerosis is one of the causes of narrowing of carotid arteries which may block partially or fully blood flow into the brain. Serious brain strokes may occur due to such types of blockages in blood flow. Early detection of the plaque and taking precautionary steps in this regard may prevent from such type of serious strokes. In this paper, we present an automatic image segmentation technique for carotid artery ultrasound images based on active contour approach. In our experimental study, we assume that ultrasound images are properly aligned before applying automatic image segmentation. We have successfully applied the automatic segmentation of carotid artery ultrasound images using snake based model. Qualitative comparison of the proposed approach has been made with the manual initialization of snakes for carotid artery image segmentation. Our proposed approach successfully segments the carotid artery images in an automated way to help radiologists to detect plaque easily. Obtained results show the effectiveness of the proposed approach.

• Applied Biological Chemistry
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• 제50권3호
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• pp.192-197
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• 2007

3D-QSARs on the fungicidal activity of N-phenylbenzenesulfonamide and N-phenyl-2-thienylsulfonamide analogues (1-37) against Phytophthora blight (Phytophthora capsici) were studied quantitatively using CoMFA and CoMSIA methods. The statistical results of the optimized CoMFA (2) model ($r^2_{cv.}(q^2)$ = 0.692 & $r^2_{ncv.}$= 0.965) show better predictability and fitness than CoMSIA (2) model ($r^2_{cv.}(q^2)$ = 0.796 & $r^2_{ncv.}$= 0.958). The fungicidal activities according to the information of the optimized CoMFA (2) model were dependent upon the steric and electrostatic fields of the molecules. Therefore, from the contribution contour maps of CoMFA (2) model, it is expected that 63% contribution was caused by the steric bulk of meta-substituent ($R_1$) on the S-phenyl ring. Also, the other contribution level of 32.9% was represented by the positive charged $R_4-group$ ($R_1$) on the N-phenyl ring and para-substituent ($R_1$) on the S-phenyl ring. A series of higher active compounds, $R_1$= 3-decyl substituent ($pred.pI_50$= 5.88) etc. were predicted based on the findings.

• Journal of the Korean Geosynthetics Society
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• 제11권4호
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• pp.1-8
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• 2012

In this study, the earth pressure, displacement and strain were compared with reinforcement types at segmental retaining wall through full scale model test. The test results found that the measurement of earth pressure and displacement at wall for the fully reinforced retaining wall are different from those for the partly reinforced retaining wall. The analyses of these results would suggest that the used of geoogrid allowed the vertical earth pressure and displacement at wall to be reduced. The horizontal earth pressure in upper and lower part of wall can change with reinforcement type and earth deformation and were larger than the active and the rest pressure. Also, the lateral earth pressure and displacement of wall have a very high a correlation. It was found that the strain contour distribution of reinforcements was occurred a large strain at cental part of wall in segmental retaining wall system.

• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권11호
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• pp.123-132
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• 1998

This paper presents a road detection technique for spaceborne synthetic aperture radar (SAR) images. Roads are important cartographic features. We incorporate an active contour model called snake as a model for the road and define a new external energy for snake which is appropriate for the road. Detecting roads in spaceborne SAR images is very difficult without other information. In this paper, digital maps are utilized to obtain the initial position and shape for snake. Only approximate geodetic location of roads appearing in SAR images can be known through geocoding process and usual digital maps also have location errors. Therefore, there exist large location offsets between the two data. By introducing initial matching procedure, the errors are reduced significantly. Then we initialize the snake's shape using the roads extracted from digital map and minimize the energies of all snake points to detect roads. We outline two problems in detection and propose a method that mitigates them.

• Transactions of the Korean hydrogen and new energy society
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• 제29권1호
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• pp.41-55
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• 2018

General polymer electrolyte fuel cell (PEMFC) operates at less than $80^{\circ}C$. Therefore liquid phase water resulting from electrochemical reaction accumulates and floods the cell which in turn increases the mass transfer loss. To prevent the flooding, it is common to employ serpentine flow channel, which can efficiently export liquid phase water to the outlet. The major drawback of utilizing serpentine flow channel is the large pressure drop that happens between the inlet and outlet. On the other hand, in the high temperature polymer electrolyte fuel cell (HT-PEMFC), since the operating temperature is 130 to $180^{\circ}C$, the generated water is in the state of gas, so the flooding phenomenon is not taken into consideration. In HT-PEMFCs parallel flow channel with lower pressure drop between the inlet and outlet is employed therefore, in order to circulate hydrogen and air in the cell less pumping power is required. In this study we analyzed HT-PEMFC's different flow channels by parallel computation using previously developed 3-D isothermal model. All the flow channels had an active area of $25cm^2$. Also, we numerically compared the performance of HT-PEMFC parallel flow channel with different manifold area and Rib interval against the original serpentine flow channel. Results of the analysis are shown in the form of three-dimensional contour polarization curves, flow characteristics in the channel, current density distribution in the Membrane, overpotential distribution in the catalyst layer, and hydrogen and oxygen concentration distribution. As a result, the performance of a real area fuel cell was predicted.

• Journal of the Institute of Electronics Engineers of Korea CI
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• 제48권1호
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• pp.1-7
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• 2011

Terrain, building location and area, and building shape information is in need of implementing 3D map. This paper proposes a method of extracting a building area by an improved semi-automatic snake algorithm. The method consists of 3-stage: pre-processing, initializing control points, and applying an improved snake algorithm. In the first stage, after transforming a satellite image to a gray image and detecting the approximate edge of the gray image, the method combines the gray image and the edge. In the second stage, the user looks for the center point of a building and the system sets the circular or rectangular initial control points by an procedural method. In the third stage, the enhanced snake algorithm extracts the building area. In particular, this paper sets the one tenn of the snake in a new way in order to use the proposed method for specializing building area extraction. Finally, this paper evaluated the performance of the proposed method using sky view satellite image and it showed that the matching percentage to the exact building area is 75%.

• Journal of Applied Biological Chemistry
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• 제53권4호
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• pp.225-231
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• 2010

To understand the inhibitory activity with changing hydroxyl substituents ($R_l-R_9$) of polyhydroxy substituted 2-phenyl-l,4-benzopyrone analogues (1-25) against tyrosinase (PDB ID: oxy-form; 1WX2), molecular docking and the three dimensional quantitative structure-activity relationships (3D-QSARs: Comparative molecular field analysis (CoMFA) & Comparative molecular similarity indices analysis (CoMSIA)) were studied quantitatively. The statistically best models were CoMFA 1 and CoMSIA 1 model from the results. The optimized CoMSIA 1 model with the sensitivity of the perturbation and the prediction produced ($dq^2'/dr_{yy'}^2$=1.009 & $q^2$=0.51l) by a progressive scrambling analysis were not dependent on chance correlation. The inhibitory activities with optimized CoMSIA 1 model were dependent upon electrostatic factor (51.4%) of substrate molecules. Contour mapping the 3D-QSAR models to the active site of tyrosinase provides new insight into the interaction between tyrosinase as receptor and 2-phenyl-l,4-benzopyrone analogues as inhibitor. Therefore, the results will he able to apply to the optimization of a new potent tyrosinase inhibitors.

• Reproductive and Developmental Biology
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• 제30권3호
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• pp.169-174
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• 2006

To search of a new porcine pheromonal odorants, the comparative molecular similarity indices analysis(CoMSIA) between porcine odorant binding protein(pOBP) as receptor and ligands of green odorants 2-(Cyclohexyloxy)tetrahydrofurane derivatives as substrate molecule were conducted and disscused quantitatively. In the optimized CoMSIA model(I-AI) with chirality($I:\;C_{1'}(R),\;C_2(S)$) in substrate molecules and atom based fit alignment(AE) of the odorants the statistical PLS results showed the best predictability of the binding affinities based on the LOO cross-validated value ${r^2}_{cv.}\;(q^2=0.856)$ and non cross-validated conventional coefficient(${r^2}_{ncv.}=0.964)$). The structural distinctions of the highest active molecules were able to understand from the interaction between pOBP and green odorants in the contour maps with CoMSIA model.

• The Korean Journal of Pesticide Science
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• 제14권1호
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• pp.72-77
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• 2010

The minimum structural requirements of R-phenoxy substituents for herbicidal evaluation of O-(2-(R)-phenoxy)-ethyl-N-aralkylcarbamate (1-15) analogues against phytoene desaturase (PDS) based on the three dimensional quantitative structure-activity relationships (3D-QSARs: CoMFA and CoMSIA) were studied quantitatively. The correlativity and predictability ($r^2_{cv.}=0.753$ and $r^2_{ncv.}=0.964$) of the CoMFA 1 model were higher than those of the rest models. The PDS inhibitory activities from the optimized CoMFA 1 model were depend upon the steric field (44.0%), electrostatic field (36.3%), and hydrophobic field (19.6%) of O-(2-(R)-phenoxy)ethyl-Naralkylcarbamate analogues. From the CoMFA contour maps on the structure of the most active compound (5), if it has the steric favor at meta-, para-position on the phenoxy ring, the negative charge favor in meta-position and positive charge favor in the outside part of para-position, the inhibitory activity will be predicted to increase. Also, if ortho-, para-position, and outside of phenoxy ring are hydrophilic favor, and meta-position is hydrophobic favor, it is predicted that the inhibitory activity against PDS will be able to increase.