• Analytical Science and Technology
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• v.27 no.4
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• pp.187-195
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• 2014

It is very important to minimize the damage of latent fingerprints at enhancing the contrast. This study proves the enhancement effects of cyanoacrylate-fumed latent fingerprints using p-dimethylaminobenzealdehyde (DMAB) on semi-porous surfaces and the influence factors. The latent fingerprints in experiment were developed for cyanoacrylate treatment in a vacuum chamber and used after drying at room temperature for 24 hours. For fluorescence staining, the cyanoacrylate-developed marks using DMAB were sublimated during 48 hours under the different conditions of surface area, temperature, atmospheric pressure. First experiment showed how surface area effects on the sublimation rate and fluorescence intensity by DMAB of particle size and container size. In addition, the fluorescence staining using DMAB with solvent-free contact method had the greatest fluorescence intensity after 36 hours and a low fluorescence intensity over a certain size of surface area. Second experiment showed that the evaporation of DMAB solid crystals got a satisfying result in a temperature of $20^{\circ}C$ and reduced time to get the greatest fluorescence intensity. It took a long time to get a optimum level of fluorescence intensity at $30^{\circ}C$ or more and it was less effective in fluorescence intensity. Third experiment on the pressure indicated that the fluorescence intensity of vacuum was weaker than nonvacuum but it was inapplicable to very high variations in pressure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5124-5130
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• 2014

Dilution of the contrast agent by analyzing the change in the signal intensity during MR angiography in accordance with the viscosity and osmotic pressure minimizes the side effects, and improves the image quality. The contrast agent molarity changes by the dilution of the contrast agent in the blood, as it is injected, which leads to a change in signal intensity. Based on this principle, a phantom was prepared and experiments were performed. After the phantom experiment, a clinical experiment was conducted using the results of the phantom experiment. From November 2013 to January 2014, a group of patients were classified into diluted contrast agent (30 persons) and undiluted (30 persons), and the signal intensity of the cerebral vessels was compared. The signal intensity of the phantom according to the molarity of the contrast agent increased sharply from 0.0125 mmol, reached a peak at 20 mmol, and achieved equilibrium from 200 mmol. Based on the study results, the signal intensity of the blood vessels in the brain through were compared in a clinical experiment. All the brain vessels in the imaging range with diluting a high content of the gadolinium contrast agent showed high signal intensity. This result supports the phantom experiment and means that using the 500mmol diluted contrast agent is better than using 1000mmol undiluted contrast agent because it is easier to approach the 20mmol level needed to achieve the highest signal intensity. This study has significance in that it can minimize the high viscosity and osmotic pressure, which can cause side effects and improve the image quality using the method of the dilution rate.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.313-323
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• 2022

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl₂ for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl₂. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K⁺ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca²⁺ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.2
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• pp.63-73
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• 2017

Segmenting the image into multiple regions is at the core of image processing. Many segmentation formulations of an images with multiple regions have been suggested over the years. We consider segmentation algorithm based on the multi-phase level set method in this work. Proposed method gives the best result upon other methods found in the references. Moreover it can segment images with intensity inhomogeneity and have multiple junction. We extend our method (GLIF) in [T. Dultuya, and M. Kang, Segmentation with shape prior using global and local image fitting energy, J.KSIAM Vol.18, No.3, 225-244, 2014.] using a multiphase level set formulation to segment images with multiple regions and junction. We test our method on different images and compare the method to other existing methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1926-1931
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• 2012

We investigated a novel fast non-uniform illumination correction method for bi-level images. The proposed method divides a bi-level image into sub-images and roughly estimates block-wise illumination by low pass filtered maximum values of sub-images. After that, we apply bilinear interpolation using the block-wise illumination to estimate non-uniform illumination, and compensate for the effect of non-uniform illumination using the estimated illumination. Since the proposed method is not based on computation intensive iterative optimization, the proposed method can be used effectively for applications that require fast correction of non-uniform illumination. In simulations, the proposed method showed more than 20 times faster speed than existing entropy minimization method. Moreover, in simulations and experiments, the restored images by the proposed method were more close to true images than images restored by conventional method.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.649-652
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• 2008

In urban area, flood risk is getting higher because of inland flood risk has grown up by changing rainfall intensity, rainfall pattern, changing land use and so on. Urban area is needed higher flood protection level to protect accumulated people, buildings and other infrastructures. However, even though former flood protection has focused on overflow from river, there is not a guide line for evaluating proper flood protection level. Thus, it is necessary to protect flood from inland flooding as well as overflow from river and need a proper method to evaluating flood protection level. This study present a method of determining flood protection elevation by using GIS tools for deciding proper flood protection level. The study result may contribute to urban flood protection measures in which inland flood risk increases.

• Tunnel and Underground Space
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• v.19 no.6
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• pp.517-525
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• 2009

Stereophotogrammetry is used to extract spatial information of an interested object by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted for a rock joint survey in mine tunnels. The orientations of discontinuities were measured from two mine tunnels with a clinocompass. To evaluate the effect of photographing light level on the stereophotogrammetry analysis, the light intensity was changed within a predefined range for every photograph. Those photographs were analyzed by using a commercial code for stereophotogrammetry - ShapeMetriX 3D, and the results from the analysis were compared with the manual measurement using a clinocompass.

• Speech Sciences
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• v.14 no.1
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• pp.121-135
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• 2007

The purpose of this paper is to examine how Korean speakers realize English stress and rhythm at the sentence level, and investigate what different acoustic characteristics of English sentence stress and rhythm Korean speakers have, compared with those of American English speakers. Stressed words in the sentence were analyzed in terms of duration, fundamental frequency, and intensity of the stressed vowel in the word with neutral stress and with emphatic stress, respectively. According to the results, when the words had emphatic stress, both Koreans' and Americans' F0 and intensity of the stressed vowel were higher than those with neutral stress. Korean speakers of English realized the sentence stress with shorter vowel duration and higher F0 than American English speakers when the words had emphatic stress. The analysis of the timing of the sentence with increased unstressed syllables showed that both Americans and Koreans produced the sentence with longer duration as the number of unstressed syllables increased. However, the duration of unstressed syllables between stressed syllables by Koreans was longer than that by Americans. Americans seemed to produce unstressed syllables between stressed syllables faster than Koreans for regular intervals of stressed syllables. This analysis implies that if there are more unstressed syllables between stressed syllables, Koreans might produce unstressed syllables and the whole sentence with longer duration.

• Journal of Ocean Engineering and Technology
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• v.1 no.1
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• pp.104-110
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• 1987

Fatigue tests by axial loading (R = 0.05) were carried out to investigate fatigue crack growth characteristics of small surface cracks in 2 1/4 Cr-1 Mo steel at room temperature by using flat specimens with a small artificial pit. All the data of the fatigue crack growth rate obtained in the present test are determined as a function of the stress intensity factor range about a semi-elliptical crack, so that the application of linear fracture mechanics to the surface fatigue crack growth and to the fatigue crack growth into depth, and all the data obtained from tests were discussed in comparison with the data of Type 304 stainless steel and two type of mild steel under the same test conditions. The obtained results are as follows: 1)When the cycle ratios are same, surface fatigue crack length and its depth are almost same and fall within a narrow scatter band in spite of different stress levels. 2)Relations of the surface fatigue crack growth rate (da/dN) and fatigue crack growth rate into depth (db/dN) to its stress intensity factor range ($\Delta K_{Ia}, \Delta K_{Ib}$) can be plotted as a straight line at log-log diagram without dependence of stress level and coincide with the data of part-through crack in various steels.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.227-233
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• 2016

This paper presents an underwater structure 3D reconstruction method using a 2D multibeam imaging sonar. Compared with other underwater environmental recognition sensors, the 2D multibeam imaging sonar offers high resolution images in water with a high turbidity level by showing the reflection intensity data in real-time. With such advantages, almost all underwater applications, including ROVs, have applied this 2D multibeam imaging sonar. However, the elevation data are missing in sonar images, which causes difficulties with correctly understanding the underwater topography. To solve this problem, this paper concentrates on the physical relationship between the sonar image and the scene topography to find the elevation information. First, the modeling of the sonar reflection intensity data is studied using the distances and angles of the sonar beams and underwater objects. Second, the elevation data are determined based on parameters like the reflection intensity and shadow length. Then, the elevation information is applied to the 3D underwater reconstruction. This paper evaluates the presented real-time 3D reconstruction method using real underwater environments. Experimental results are shown to appraise the performance of the method. Additionally, with the utilization of ROVs, the contour and texture image mapping results from the obtained 3D reconstruction results are presented as applications.