• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.1-9
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• 1999

Applicability of the pressure gradient method which is formulated based on pressure gradient is verified against turbulent flow analysis. In the pressure gradient method, pressure gradient instead of pressure itself is obtained using continuity constraint. Since correct pressure gradient is found only when mass conservation is satisfied, pressure gradient method can reflect physics of flow field properly The pressure gradient method is formulated with semi-staggered grid system which locates each primitive variables on the same grid point but evaluates pressure gradient in-between. This grid system ensures easy programming and reflection of correct physics in analysis. For verifying applicability of this method, the pressure gradient method is applied to turbulent flow analysis with low Reynolds number $\kappa$-$\varepsilon$ model. Turbulent flows include fully developed channel flow, backward-facing step flow, and conical diffuser flow. Prediction results show that the pressure gradient method can be applied to turbulent flow analysis. However, the pressure gradient method requires somewhat long computation time. Proper way to find optimum under-relaxation factor, $\gamma$, is also need to be developed.

• Journal of Korean Biological Nursing Science
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• v.22 no.4
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• pp.279-287
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• 2020

Purpose: Some of the adolescent drinks more sugar-sweetened beverages. However, there is little evidence on the effect of eating behavior on emotional state and neurochemical changes under stress, especially on the levels of typical inhibitory neurotransmitters and gamma-aminobutyric acid. This article demonstrates that sucrose or saccharin drink reduces stress-related behavior responses and GABAergic deficits in adolescent rats. Methods: We randomly assigned 7-weeks-old Sprague-Dawley male rats to three groups: control group (Control), restraint stress only group (Stress), and restraint stress with unrestricted access to saccharin solution (Saccharin) and sucrose solution (Sucrose) as a positive control. We evaluated both anxious and depressive moods using an open field test and forced swim test, respectively. Using western blot analyses, the expression of a GABA-synthesizing enzyme, glutamate decarboxylase-67 (GAD67) and GABAergic markers, including calbindin and parvalbumin was assessed in the prefrontal cortex and the amygdala. Results: We found that both the drinks alleviated anxiety and depressive moods, induced significant attenuation in GAD67 level, and reduced calbindin level under stress in the prefrontal cortex and the amygdala. Conclusion: The results provide an understanding of the effect of sucrose or saccharin drink on stress-related responses. We propose the consumption of sweet drinks as a plausible strategy to alleviate stress-related alterations in adolescents.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.285-292
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• 2001

In this paper, the analysis model of a composite electromagnetic interference environment is proposed, and the composite interference consists of three types, i.e., impulse, sinusoidal, and rectangular type. Also, we have derived the p.d.f of the amplitude of the composite interference. And using a derived p.d.f, we have evaluated the performance of 16QAM (Quadrature Amplitude Modulation) system in a composite electromagnetic interference environment. From the results, it is known that when impulse type interference is weaker than the others, the shape of p.d.f is dominantly governed by the power component ratio of sinusoidal and rectangular type interference. On the other hand, when impulse type interference is stronger, the effect of the other two interference becomes insignificant. Also, It is shown that the smaller both impulsive index (A) and the mean power component ratio ($\Gamma$') in impulse type interference are, the worse the performance of 16QAM system is.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.683-692
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• 2009

On-site remote sensing technique by using single lens reflex(SLR) digital camera will be expected as the useful tool for the vegetation measurement field such as a crop growth management, the monitoring of revegetation slope and the evaluation of environment. We reviewed the availability of the vegetation measurement using a digital camera which is sailed for general-purpose. As a result, we could analysis relationship with the illuminance of image plane and incidence energy of multitemporal observation images by doing gamma correction and exposure compensation. And also, we proposed the model formulas for the correction of influences of capturing angle and illuminance. In addition, we obtained high correlation of normalized difference vegetation index(NDVI) between digital camera and spectral photometer.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.114-125
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• 2006

objective : The purpose of this research is to examine the effects of Scutellaria Radix(SR) extract on immune cells and cytokines in ovalbumin(OVA)-induced asthmatic mice. Methods : In vivo, C57BL/6 mice were sensitized and handicapped by OVA for 9 weeks. In this experiment, one group was not treated, and the other group was treated with SR extract for six weeks(five times per week) and analyzed by ELISA and flow cytometer. Results : In vivo, there were significant decreases in eosinophils, IL-4, IL-13 in BALF (bronchoalveolar lavage fluid) compared with that of control group. However,$IFN{\gamma}$ in the SR group increased significantly compared with that of control group. Additionally, the population of $CD3e^-/CCR3^+,\;CD69^+/CD3e^+,\;IgE^+/B220^+,\;CD11b^+/Gr-1^+$ cells in the SR group decreased compared with that of control group. conclusion : The results of this study support a role for SR as an effective treatment for asthma in its experimental success in significantly decreasing inflammation and asthma reactions, and in increasing $IFN{\gamma}$, Which helps prevent such reactions.

• Journal of the Korean Vacuum Society
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• v.20 no.5
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• pp.345-355
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• 2011

GaAs-based metamorphic high electron mobility transistors (MHEMTs) and InP-based high electron mobility transistors (HEMTs) have good microwave and millimeter-wave frequency performance with lower minimum noise figure. MHEMTs have some advantages, especially for cost, compared with InP-based ones. In this paper, InAlAs/InxGa1-xAs/GaAs MHEMTs are simulated for DC/RF small-signal analysis. The hydrodynamic simulation parameters are calibrated to a fabricated 0.1-${\mu}m$ ${\Gamma}$-gate MHEMT device having the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ heterostructure on the GaAs substrate, and the simulations for RF small-signal characteristics are performed, compared with the measured data, and analyzed for the devices. In addition, the simulations for the DC/RF characteristics of the MHEMTs with different gate-recess structures are performed, compared and analyzed.

• The Journal of Korean Medicine
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• v.37 no.3
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• pp.13-26
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• 2016

Objectives: Inflammatory bowel disease (IBD) is chronic inflammatory disorders of the intestines. Due to limitation of conventional treatment including steroids, herbal medicines have emerged as possible therapeutic options for IBD. The purpose of the current study was to investigate the therapeutic and prophylactic effects and mechanisms of Zostera Marina water extract (ZME) on DSS-induced colitis. Methods: Colitis was induced by DSS in Balb/c mice. In pre-treatment setting, ZME was administered 7 days before DSS treatment and in co-treatment setting, ZME was simultaneously administrated with DSS treatment. In both settings, ZME 100, 300 and 1000 mg/kg were orally administered twice a day, respectively. Mice weight and clinical findings were measured daily. Colon length, macroscopic findings and histological damages of colon mucosa were assessed at the end of experiments. The levels of cytokines including TNF-${\alpha}$, IFN-${\gamma}$, IL-$1{\beta}$, IL-6, IL-10 and IL-17 were measured by Biometric Multiplex Cytokine Profiling method. Results: In a dose dependent manner, ZME significantly inhibited the colon shortening, and improved macroscopic score and histological score. However, there were insignificant changes on inhibition of weight loss and improvement of clinical score. There were no significant differences of effects between co-treatment and pre-treatment settings. ZME 300 and 1000 mg/kg groups significantly inhibited IFN-${\gamma}$. Only ZME 1000 mg/kg group significantly inhibited TNF-${\alpha}$, IL-$1{\beta}$ and IL-6. Conclusions: The current results show the possibility of therapeutic use and its prophylactic application of ZME on inflammatory bowel diseases. Future studies for targeted mechanisms of ZME are needed.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.88-98
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• 2001

in this paper, we imlemented design pattern retrieval system for efficient managemant and reusability of design patterns. Pattern is conssisted of property information and meta information id used for similarity measurement on classification and retrieval of patterns.Meta information od used for UML modeling of patterns. We classified design patterns with the empirical scope in addition to Gamma's basic classification. also we used E-SARM for retrieval represented UML diagram with pattern meta information, and simulated the environment so as to obtain best result on applying to retrieval of design pattern. This system is able ro resister new patterns through pattern viewer and manages these patterns with property informaiton and meta information. Thus this system supports efficient management of patterns, UML modeling, priority pattern retrieval, higher reusability and reduces pattern selection cost.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.114-123
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• 2014

Vehicle Black Box (Event Data Recorder EDR) only recognizes the general surrounding environments of load. In addition, general EDR is difficult to recognize the images of a sudden illumination change. It appears that the lens is being a severe distortion. Therefore, general EDR does not provide the clues of the circumstances of the accident. To solve this problem, we estimate the value of Normalized Luminance Descriptor(NLD) and Normalized Contrast Descriptor(NCD). Illumination change is corrected using Normalized Image Quality(NIQ). Second, we are corrected lens distortion using model of Field Of View(FOV) based on designed method of fisheye lens. As a result, we propose integration algorithm of two methods that correct distortions of images using each Gamma Correction and Lens Correction in parallel.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.1
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• pp.5-11
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• 2001

Melting behavior and bridge phenomenon of solder paste, which is essential for surface mount technology in pachaging, were investigated. Solder paste of Sn-37%Pb was printed on Cu-pattern of PCB, and heated over melting point. Melting behavior of the paste was observed using CCD-camera. In order to modelize the melting and agglomeration phenomena of paste, two solder balls of 0.76 mm diameter were used. As experimental results, the paste start to melt from the margin of the printed shape. The height of the melted paste decreased from 270 $\mu\textrm{m}$ to 200 $\mu\textrm{m}$ firstly, and finally recovered to 250 $\mu\textrm{m}$ During the melting procedure, pores were evolved from the molted paste. Concerning melting model of solder ball, relationship between contact area of solder ball and soldering time was derived as $\chi^2/t=4r \; \gamma/\eta=7.56 m^2$/s at $280^{\circ}C$.