• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3553-3558
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• 2013

The three dimensional-quantitative structure activity relationship (3D-QSAR) studies on chemical features of pyridine-2-amines in the external region of c-Met active site (ER chemical features of pyridine-2-amines) were conducted by docking, comparative molecular field analysis (CoMFA), and topomer CoMFA methods. The CoMFA model obtained the partial least-squares (PLS) statistical results, cross-validated correlation coefficient ($q^2$) of 0.703, non cross-validated correlation coefficient ($r^2$) of 0.947 with standard error of estimate (SEE) of 0.23 and the topomer CoMFA obtained $q^2$ of 0.803, $r^2$ of 0.940, and SEE of 0.24. Further, the test set was applied to validate predictive abilities of models, where the predictive $r^2$ ($r{^2}_{pred}$) for CoMFA and topomer CoMFA models were 0.746 and 0.608, respectively. Each contribution of ER chemical features of pyridine-2-amines to the inhibitory potency showed correlation coefficients, $r^2$ of 0.670 and 0.913 for two core parts, 3-(benzo[d]oxazol-2-yl)pyridine-2-amine and 3-(1-(2,6-dichloro-3-fluorophenyl)ethoxy) pyridine-2-amine, respectively, with corresponding experimental $pIC_{50}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.645-651
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• 2016

Effects of pressure-side winglet width on the tip leakage flow and aerodynamic loss downstream of a turbine blade with a pressure-side squealer rim have been investigated for the tip gap-to-span ratio of h/s = 1.36%. The pressure-side squealer has a fixed height-to-span ratio of $h_p/s=3.75%$ and the pressure-side winglet, which is installed at an elevation of tip surface, has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results show that with increasing w/p, aerodynamic loss in the passage vortex region decreases, whereas that in the leakage flow region increases. As a result, the mass-averaged loss coefficient all over the measurement plane tends to decrease minutely with the increment of w/p. It is concluded that the pressure-side winglet for the pressure-side squealer tip can hardly contribute to the tip-leakge loss reduction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.891-896
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• 2011

In this study, experiments were carried out to investigate the convective heat transfer characteristics of rectangular microchannels. The sample used in the experiments contained 20 rectangular microchannels in parallel. The channels had a hydraulic diameter of 700 ${\mu}m$. Distilled water was used as the working fluid. In the experiments, the Reynolds number ranged from 400 to 800, heat flux ranged from 35 to 85 kW/$m^2$, and the inlet fluid temperature was $20^{\circ}C$. As a result, the convective heat transfer coefficient increased upon increasing the Reynolds number and ranged from 4.6 to 6.4 kW/$m^2/^{\circ}C$ in the thermally fully developed region. Moreover, the higher the Reynolds number, the longer the thermal entry length in the rectangular microchannels. However, it was observed that a variable heat flux did not affect the thermal entry length. In conclusion, a correlation was proposed to indicate the heat transfer characteristics in a thermally fully developed region.

• Journal of Korea Multimedia Society
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• v.16 no.7
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• pp.829-840
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• 2013

In this paper, we propose a new lung segmentation method for chest x-ray images which can take both global and local properties into account. Firstly, the initial lung segmentation is computed by applying the active shape model (ASM) which keeps the shape of deformable model from the pre-learned model and searches the image boundaries. At the second segmentation stage, we also applied the localizing region-based active contour model (LRACM) for correcting various regional errors in the initial segmentation. Finally, to measure the similarities, we calculated the Dice coefficient of the segmented area using each semiautomatic method with the result of the manually segmented area by a radiologist. The comparison experiments were performed using 5 lung x-ray images. In our experiment, the Dice coefficient with manually segmented area was $95.33%{\pm}0.93%$ for the proposed method. Effective segmentation methods will be essential for the development of computer-aided diagnosis systems for a more accurate early diagnosis and prognosis regarding lung cancer in chest x-ray images.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.111-117
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• 2004

Most of digital subtraction methods in dental radiography are based on registration using manual landmarks. We have developed an automatic registration method without using the manual selection of landmarks. By restricting a geometrical matching of images to a region of interest (ROl), we compare the cross-correlation coefficient only between the ROIs. The affine or perspective transform parameters satisfying maximum of cross-correlation between the local regions are searched iteratively by a fast searching strategy. The parameters are searched on the 1/4 scale image coarsely and then, the fine registration is performed on the original scale image. The developed method can match the images corrupted by Gaussian noise with the same accuracy for the images without any transform simulation. The registration accuracy of the perspective method shows a 17% improvement over the manual method. The application of the developed method to radiography of dental implants provides an automatic noise robust registration with high accuracy in almost real time.

• Journal of Sensor Science and Technology
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• v.3 no.3
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• pp.36-44
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• 1994

A fiber-optic temperature sensor utilizing InP as a sensing medium was implemented and tested to determine the dependance of the optical characteristics of InP on physical parameters for the use as design parameters in this type of sensors. The optical absorption coefficient of InP has been determined through the experimental measurement of the fundamental optical absorption characteristics at various temperature points. The transmission characteristics of light source at three temperature points($249^{\circ}K$, $298^{\circ}K$, $369^{\circ}K$) are computed from the optical absorption coefficient for a fixed length of InP. A series of measurement concluded that optical absorption edge moves to longer wavelength region at a speed of 0.42 nm / $^{\circ}K$ as the specimen gets hotter, and that increasing the thickness of the InP sensing layer shifts power density curve to lower temperature region.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.99-106
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• 2013

DME (Di-Methyl Ether) is synthetic product that is produced through dehydration of methanol or a direct synthesis from syngas. And it is able to save fossil fuel and reduce pollutants of emission such as PM and $CO_2$. In spite of its advantages it is difficult to design DME fuelled engine system because DME fuel may cause to severely generate cavitation and corrosion in fuel delivery system due to physical properties of DME. Therefore, in this study three-dimensional internal flow characteristics with consideration of cavitation were predicted in the DME injector using diesel and DME fuel. Moving grid technique was employed to describe needle motion and 1-D hydraulic simulation of injector was also simulated to obtain transient needle motion profiles. The results of simulation show that cavitations was generated at the inlet of nozzle near high velocity region both diesel and DME. And mass flow rate of DME is reduced by 4.73% compared to that of diesel at maximum valve lift because cavitation region of DME is much more larger. To increase flow rate of DME injector, internal flow simulation has been conducted to investigate the nozzle hole inner R-cut effect. The flow rates of diesel and DME increase as R-cut increases, and flow coefficient of DME fuel injector was increased by 6.3% on average compared with diesel fuelled injector. Finally, optimum shape of DME injector nozzle is suggested through the comparison of flow coefficient with variation of nozzle hole inner R-cut.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1405-1412
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• 2018

Korean-PEQ (prosthesis evaluation questionnaire) was developed and verified its validity research but, evaluating its reliability applied to the lower extremity amputees have not been conducted. The aim of this study was to apply the Korean-PEQ for lower extremity amputees to evaluate the reliability. As a result, all of the items responding of Korean-PEQ shown to less than 15% ceiling effect and floor effect. therefore, the results were shown to be appropriate. Korean-PEQ reliability of each region of intra-class coefficient was shown to .719(95% CI .600~.811)~920(95%CI .890~.945) and the inter-region reliability was higher as 0.958. Item internal consistency Cronbach's ${\alpha}$ values are shown as higher .910.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.8
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• pp.408-418
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• 2017

Supercritical carbon dioxide ($sCO_2$) power system is emerging technology because of its high cycle efficiency and compactness. Meanwhile, PCHE (Printed Circuit Heat Exchanger) is gaining attention in $sCO_2$ power system technology because PCHE with high pressure-resistance and larger heat transfer surface per unit volume is fundamentally needed. Thermo-fluidic characteristics of $sCO_2$ in the micro channel of PCHE should be investigated. In this study, heat transfer characteristics of $sCO_2$ of various inlet conditions and cross-sectional shapes of single micro channel were investigated experimentally. Experiment was conducted at supercritical state of higher than critical temperature and pressure. Test sections were made of copper and hydraulic diameter was 1 mm. Convective heat transfer coefficients were measured according to each interval of the channel and pressure drop was also measured. Convective heat transfer coefficients from experimental data were compared with existing correlation. In this study, using measured data, a new empirical correlation to predict near critical region heat transfer coefficient is developed and suggested. Test results of single channel will be used for design of PCHE.

• Korean Journal of Materials Research
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• v.19 no.4
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• pp.228-231
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• 2009

Phase transition in ferroelectric polymer is very interesting behavior and has been widely studied for real device applications, such as actuators and sensors. Through the phase transition, there is structural change resulting in the change of electrical and optical properties. In this study, we fabricated the Febry-Perot interferometer with the thin film of ferroelectric P(VDF-TrFE) 50/50 mol% copolymer, and thermo-optical properties were investigated. The effective thermo-optical coefficient of P(VDF-TrFE) was obtained as $2.3{\sim}3.8{\times}10^{-4}/K$ in the ferroelectric temperature region ($45^{\circ}C{\sim}65^{\circ}C$) and $6.0{\times}10^{-4}/K$ in the phase transition temperature region ($65^{\circ}C{\sim}85^{\circ}C$), which is a larger than optical silica-fiber and PMMA. The resonance transmission peak of P(VDF-TrFE) with the variation of temperature showed hysteretic variation and the phase transition temperature of the polymer in heating condition was higher than in the cooling condition. The elimination of the hysteretic phase transition of P(VDF-TrFE) is necessary for practical applications of optical devices.