• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1239-1250
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• 2004

This research was concerned with the enhancement of heat transfer by surfactant added to the aqueous solution of LiBr. Different vertical tubes were tested with and without an additive of normal octyl alcohol. The test tubes are a bare inner surface. a groove inner surface, a corrugated inner surface and a spring inserted inner surface tubes. The additive concentration was about 0.08 mass%. The heat transfer coefficient was measured as a function of the film Reynolds number in the range of 20~200. Experiments were carried out at higher cooling water temperature of $35^{\circ}C$ to simulate an air cooling condition for several kinds of absorber testing tubes. The experimental results were compared with and without surfactant. The enhancement of heat transfer by Marangoni convection effect which was generated by addition of the surfactant is observed in each test tube. Especially, it is clarified that the tube with an inserted spring has the highest enhancement effect.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1455-1464
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• 2006

In this paper, we propose an adaptive image enhancement algorithm. The proposed algorithm is classified with the MIE technique for intensity enhancement of input image and MSE techniques for saturation enhancement. The MIE technique is proposed to control the gamut mapping problem and a sudden change in image-brightness while Luminance signal is processing, The MSE techniques are proposed to control de-saturation or over-saturation while chrominance signal is processing. The proposed algorithm is focused on processing preference color for human vision in order to generate better image quality than the algorithms focused on processing uniformly to whole images, This algorithm can be applied to a monitor, TV and other display devices for high quality image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.985-988
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• 2007

This paper presents techniques to make image enhancement using unsharp masking. It is the technique to make image enhancement by automatically find the three parameters that makes hard to use the unsharp mask technique. To optimize the three parameters(Threshold, Amount, Radius), at first classify the pixels in the image to three groups, and then according to the groups, apply the unsharp mask to the image differently. We experimented and analyzed the rate of image enhancement by comparing images which is enhanced by human and which is enhanced by proposed technique.

• Journal of Home Health Care Nursing
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• v.20 no.2
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• pp.105-112
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• 2013

Purpose: The purpose of the present study was to assess the effectiveness of a nursing skills enhancement program in improving the self-efficacy and self-esteem of senior nursing students. Methods: This was a nonequivalent control group pretest-posttest design study that enrolled 306 senior nursing students. The nursing students were randomly assigned to an experimental(n=132) or control group (n=174), and students assigned to the experimental group completed a nursing skills enhancement program, which consisted of four skills training components: IV infusion, enema, $O_2$ therapy by means of cannulation and urinary catheterization. Data were analyzed with frequency, the chi-squared test, and the paired t-test using the SPSS/pc 15.0 statistical program. Results: Our results showed that the self-esteem and self-efficacy of nursing students who were assigned to the nursing skills enhancement program were significantly better compared to those of nursing students in the control group (t=10.198 and t=6.452, for self-efficacy and self-esteem, respectively, p<.001 for both variables). Conclusion: Our findings clearly show that a nursing skills enhancement program is effective in improving the self-efficacy and self-esteem of senior nursing students.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5112-5129
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• 2019

Image enhancement is a challenging problem in the field of image processing, especially low-light color images enhancement. This paper proposed a robust and comprehensive enhancement method based several points. First, the idea of bright channel is introduced to estimate the illumination map which is used to attain the enhancing result with Retinex model, and the color constancy is keep as well. Second, in order eliminate the illumination offsets wrongly estimated, morphological closing operation is used to modify the initial estimating illumination. Furthermore, in order to avoid fabricating edges, enlarged noises and over-smoothed visual features appearing in enhancing result, a multi-scale closing operation is used. At last, in order to avoiding the haloes and artifacts presented in enhancing result caused by gradient information lost in previous step, guided filtering is introduced to deal with previous result with guided image is initial bright channel. The proposed method can get good illumination map, and attain very effective enhancing results, including dark area is enhanced with more visual features, color natural and constancy, avoiding artifacts and over-enhanced, and eliminating Incorrect light offsets.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.104-111
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• 2010

This paper presents an adaptive image enhancement method using the spatial frequency property in the DCT(discrete cosine transform) compressed domain. The dc coefficients, the illumination components of image, are adjusted to compress the dynamic range of image, and the ac coefficients are modified to enhance the contrast by using the human visual system(HVS) and the spatial frequency property. The ac coefficients are separated into vertical direction, horizontal direction, and mixed spatial frequency components, and adaptively modified to minimize the block artifacts that possibly occur in the image enhancement. The proposed method using dynamic range compression and adaptive contrast enhancement shows the advanced performance without the block artifact compared with existing method.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.4
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• pp.467-472
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• 2005

The principal objective of enhancement methods is to process an image so that the output image is more suitable than the original image lot a specific application. Images taken in the night can be low-contrast images because of poor environments. In this paper, we compared the performance of Image Contrast Enhancement Technique Using Clustering Algorithm(ICECA) with those of color adjustment methods such as Histogram Equalization(HE), Brightness Preserving Bi-Histogram Equalization(BBHE), and the Multi-Scale Refiner(MSR). We compared these methods by applying the image enhancement methods to a set of diverse images.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.165-172
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• 2005

Heat transfer enhancement of three types of brazed plate heat exchangers has been evaluated experimentally. The effects of flow resonance in a plate heat exchanger on the heat transfer rate and pressure drop have been investigated in a wide range of mass flow rates in detail. The problem is of particular interest in the innovative design of a plate heat exchanger by flow resonance. The results obtained indicate that both heat transfer coefficient and pressure drop are increased as mass flow rate is increased, as expected. It is also found that the heat transfer enhancement is increased with an increase in the plate pitch, while the heat transfer is decreased with a decrease in the chevron angle. Pressure drop also increased with an increase in the plate pitch and with a decrease in the chevron angle. Heat transfer enhancement in the plate heat exchangers is maximized by flow resonance and the resonance frequency of the present plate heat exchangers is found to be in the range of $10~15\;Hz$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1009-1016
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• 2001

The heat transfer enhancement by pulsatile flow in a triangular grooved channel has been experimentally investigated in this study The experiment was performed in the ranges of the Reynolds number from 270 to 910, the pulsatile fraction from 0.125 to 0.75, and the Strouhal number from 0.084 to 0.665. It was measured that the heat transfer improves up to 350% compared with the steady flow case at Re=270,$\eta=0.5$, and St=0.335. The heat transfer enhancement was found to increase as the pulsatile fraction increases and the Reynolds number decreases. It was also found that the heat transfer enhancement is maximized at a specific pulsatile frequency satisfying the resonant condition. The nondimensional frequency, i.e., the Strouhal number at the resonant condition was found to increase as the Reynolds number decreases. The flow visualization revealed that the heat transfer enhancement results from the strong mixing caused by the repeating sequence of vortex formation, rotation and subsequent ejection from the grooves by the pulsatile flow.

• Advances in Traditional Medicine
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• v.3 no.1
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• pp.34-39
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• 2003

We investigated the immune enhancement effects of JaSaengHwan (JSH). The forced swimming test (FST) has been used as a screening model for new immune enhancement agents. We found that JSH (0.1 mg/ml) significantly reduced the immobility time in the FST compared to the control. Also, we investigated the effect of JSH on the proliferation of T cell and production of cytokines in human T-cell line, MOLT-4 cells and mouse peritoneal macrophages. JSH (1 mg/ml) significantly increased the cell proliferation by $46.78{\pm}6.41%$ (p<0.05) and also significantly increased the interleukin (IL)-2, IL-4 and interferon $(IFN)-{\gamma}$ production compared with media control (about 2-fold for IL-2, 3-fold for IL-4 and 1.5-fold for $IFN-{\gamma}$, p<0.05) at 24 h. In addition, JSH increased the production of IL-12 on the mouse peritoneal macrophages (by 3.6-fold for IL-12, p<0.05). In conclusion, these data indicate that JSH may have an immune-enhancement effect.