• Atmosphere
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• v.17 no.2
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• pp.159-169
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• 2007

A comparison of the three land cover data sets (United States Geological Survey: USGS, International Geosphere Biosphere Programme: IGBP, and University of Maryland: UMd), derived from 1992-1993 Advanced Very High Resolution Radiometer(AVHRR) data sets, was performed over the Asian continent. Preprocesses such as the unification of map projection and land cover definition, were applied for the comparison of the three different land cover data sets. Overall, the agreement among the three land cover data sets was relatively high for the land covers which have a distinct phenology, such as urban, open shrubland, mixed forest, and bare ground (>45%). The ratios of triple agreement (TA), couple agreement (CA) and total disagreement (TD) among the three land cover data sets are 30.99%, 57.89% and 8.91%, respectively. The agreement ratio between USGS and IGBP is much greater (about 80%) than that (about 32%) between USGS and UMd (or IGBP and UMd). The main reasons for the relatively low agreement among the three land cover data sets are differences in 1) the number of land cover categories, 2) the basic input data sets used for the classification, 3) classification (or clustering) methodologies, and 4) level of preprocessing. The number of categories for the USGS, IGBP and UMd are 24, 17 and 14, respectively. USGS and IGBP used only the 12 monthly normalized difference vegetation index (NDVI), whereas UMd used the 12 monthly NDVI and other 29 auxiliary data derived from AVHRR 5 channels. USGS and IGBP used unsupervised clustering method, whereas UMd used the supervised technique, decision tree using the ground truth data derived from the high resolution Landsat data. The insufficient preprocessing in USGS and IGBP compared to the UMd resulted in the spatial discontinuity and misclassification.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.491-502
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• 2014

As meteorology is the driving force for lake thermodynamics and mixing processes, the effects of climate change on the physical limnology and associated ecosystem are emerging issues. The potential impacts of climate change on the physical features of a reservoir include the heat budget and thermodynamic balance across the air-water interface, formation and stability of the thermal stratification, and the timing of turn over. In addition, the changed physical processes may result in alteration of materials and energy flow because the biogeochemical processes of a stratified waterbody is strongly associated with the thermal stability. In this study, a novel modeling framework that consists of an artificial neural network (ANN), a watershed model (SWAT), a reservoir operation model(HEC-ResSim) and a hydrodynamic and water quality model (CE-QUAL-W2) is developed for projecting the effects of climate change on the reservoir water temperature and thermal stability. The results showed that increasing air temperature will cause higher epilimnion temperatures, earlier and more persistent thermal stratification, and increased thermal stability in the future. The Schmidt stability index used to evaluate the stratification strength showed tendency to increase, implying that the climate change may have considerable impacts on the water quality and ecosystem through changing the vertical mixing characteristics of the reservoir.

• Journal of the Korean Society of School Health
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• v.10 no.2
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• pp.169-178
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• 1997

In order to investigate the complaint rates of subjective fatigue symptoms and study the relationship between them and body type, health awareness in middle school students, we carried out a survey of 1,209 students (654 boy students and 555 girl students) at a middle school in Taejon City by a self-recorded questionnaire. The survey was conducted in June, 1997. The results obtained were as follows: 1. Among complaints of fatigue, "feel like lying down" was the highest, followed by "feel anxious about things", "feel drowsy", "yawning a lot", "eye strain" and "whole body feels tired" in descending order. 2. In the average weighted score of fatigue complaint, dullness and sleepiness (I) was the highest, followed by a difficulty in concentration (II) and bodily projection of fatigue (III) in descending order. Fatigue seems to create mental stress rather than physical burdens. 3. In the classification of body type based on the $R\ddot{o}hrer$ index, the obesity type (145 and above) was 11.0%, standard type (110~144) was 64.7% and leptosomic type (l09 and below) was 24.3%. Comparison between both sexes revealed that the rate of obesity and leptosomic types were significantly higher in boy students than in girl students. 4. In terms body type awareness, the statistics are the following: those who consider themselves to be standard type, 44.3%, slightly obese 24.5%, leptosomic, 23.5% and obese 7.8%. However, the level of obesity awareness was significantly higher in girl students than in boy students. 5. As for health awareness, 36.5% considered themselves healthy, 5.4% generally healthy and 10.1% a little unhealthy, but the level of unhealthy awareness was higher in girl students than in boy students. 6. In the relationship between body type and health awareness, most students thought that they were obese in spite of their standard body type. Also, many students who were obese and leptosomic tended to consider themselves to be a little unhealthy. 7. The more the students were obese or felt unhealthy, the more the average weighted score of fatigue complaints was high.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.87-107
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• 2003

It was demonstrated that Transactivating transcriptional activator(TAT) protein from HIV-1 shown to enter cells when added to the surrounding media. TAT peptide chemically attached to various proteins was able to deliver these proteins to various cell and even in tissues in mice with high levels in heart and spleen. In this study, the tripeptide GKH(Glycine-Lysine-Histidine) derived from Parathyroid hormone (PTH), which was known as lipolytic peptide, is attached to 9-poly Lysine(TAT) to be used as a cosmetic ingredient for slimming products. When Glycerol release, expressed as extracellular glycerol concentration, is lipolysis index, TAT-GKH at $10^{-5}$mo1/L induces approximately 41.5% maximal lipolytic effects in epididymal adipocytes isolated from rats, compared with basal lipolysis. Epididymal adipose tissues of male rats is assessed ex vivo by microdialysis. Probes are perfused with Ringer solution in which increasing concentrations of TAT-GKH. The perfusion of TAT-GKH induces lipolytic effect. Penetration study showed that TAT-GKH efficiently elevates 36 times higher penetration into the excised hairless mice skin than GKH. in vivo study showed that TAT-GKH had a better effect upon the relative volume of eye bag after 28 days of application on twenty(+2) healthy female volunteers. It was identified that TAT-GKH increases penetration enhancement and lipolytic effects in both in vitro, ex vivo and in vivo.

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.541-549
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• 2023

The aim of this study wasto conduct a quantitative analysis of CT image quality according to an algorithm designed to reduce metal artifacts induced by metal components. Ten baseline images were obtained with the standard filtered back-projection algorithm using spectral detector-based CT and CT ACR 464 phantom, and ten images were also obtained on the identical phantom with the standard filtered back-projection algorithm after inducing metal artifacts. After applying the to raw data from images with metal artifacts, ten additional images for each were obtained by applying the virtual monoenergetic algorithm. Regions of interest were set for polyethylene, bone, acrylic, air, and water located in the CT ACR 464 phantom module 1 to conduct compare the Hounsfield units for each algorithm. The algorithms were individually analyzed using root mean square error, mean absolute error, signal-to-noise ratio, peak signal-to-noise ratio, and structural similarity index to assess the overall image quality. When the Hounsfield units of each algorithm were compared, a significant difference was found between the images with different algorithms (p < .05), and large changes were observed in images using the virtual monoenergetic algorithm in all regions of interest except acrylic. Image quality analysis indices revealed that images with the metal artifact reduction algorithm had the highest resolution, but the structural similarity index was highest for images with the metal artifact reduction algorithm followed by an additional virtual monoenergetic algorithm. In terms of CT images, the metal artifact reduction algorithm was shown to be more effective than the monoenergetic algorithm at reducing metal artifacts, but to obtain quality CT images, it will be important to ascertain the advantages and differences in image qualities of the algorithms, and to apply them effectively.

• Progress in Medical Physics
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• v.26 no.4
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• pp.258-266
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• 2015

The modern radiotherapy technique which delivers a large amount of dose to patients asks to confirm the positions of patients or tumors more accurately by using X-ray projection images of high-definition. However, a rapid increase in patient's exposure and image information for CT image acquisition may be additional burden on the patient. In this study, by introducing structural similarity (SSIM) index that can effectively extract the structural information of the image, we analyze the differences between daily acquired x-ray images of a patient to verify the accuracy of patient positioning. First, for simulating a moving target, the spherical computational phantoms changing the sizes and positions were created to acquire projected images. Differences between the images were automatically detected and analyzed by extracting their SSIM values. In addition, as a clinical test, differences between daily acquired x-ray images of a patient for 12 days were detected in the same way. As a result, we confirmed that the SSIM index was changed in the range of 0.85~1 (0.006~1 when a region of interest (ROI) was applied) as the sizes or positions of the phantom changed. The SSIM was more sensitive to the change of the phantom when the ROI was limited to the phantom itself. In the clinical test, the daily change of patient positions was 0.799~0.853 in SSIM values, those well described differences among images. Therefore, we expect that SSIM index can provide an objective and quantitative technique to verify the patient position using simple x-ray images, instead of time and cost intensive three-dimensional x-ray images.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.83-94
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• 2012

Slopes are commonly formed both above and below roads located in mountainous terrain and along riversides. The Buk-sil site, a cut slope formed below the road, collapsed in October, 2010. A field investigation determined the causes of failure as improper drainage of valley water from the slope above the road and direct seepage of road-surface water. These factors may have accelerated the collapse via complex interaction between water and sub-surface structures such as bedding. Projection analysis of the site showed the possible involvement of plane, wedge, and toppling failure. Safety factors calculated by Limit Equilibrium Analysis for plane and wedge failure were below the standard for wet conditions. The wetness index, analyzed using topographic factors of the study area, was 9.0-10.5, which is high compared with the values calculated for nearby areas. This finding indicates a high concentration of water flow. We consider that water-flow control on the upper road is crucial for enhancing slope stability at the Buk-sil site.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.499-514
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• 2011

An underlying assumption of traditional hydrologic frequency analysis is that climate, and hence the frequency of hydrologic events, is stationary, or unchanging over time. Under stationary conditions, the distribution of the variable of interest is invariant to temporal translation. Water resources infrastructure planning and design, such as dams, levees, canals, bridges, and culverts, relies on an understanding of past conditions and projection of future conditions. But, Water managers have always known our world is inherently non-stationary, and they routinely deal with this in management and planning. The aim of this paper is to give a brief introduction to non-stationary extreme value analysis methods. In this paper, a non-stationary hydrologic frequency analysis approach is introduced in order to determine probability rainfall consider changing climate. The non-stationary statistical approach is based on the conditional Generalized Extreme Value(GEV) distribution and Maximum Likelihood parameter estimation. This method are applied to the annual maximum 24 hours-rainfall. The results show that the non-stationary GEV approach is suitable for determining probability rainfall for changing climate, sucha sa trend, Moreover, Non-stationary frequency analyzed using SOI(Southern Oscillation Index) of ENSO(El Nino Southern Oscillation).

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.421-421
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• 2006

The light and energy-efficiency of classical liquid crystal displays is notoriously poor due to the use of absorption-based linear polarisers and colour filters. For instance, the light efficiency of PVAL polarisers is typically between 40 and 45 % and the colour filters have a typical efficiency below 35 % which results in a total light and energy-efficiency of the display below 10 %. In the past, a variety of polarizers were developed with an enhanced efficiency in generating linearly polarized light. Typically, these polarizers are based on the polarisationselective reflection, scattering or refraction of light i.e. one polarisation direction of light is directly transmitted to the LCD/viewer and the other polarization direction of light is depolarised and recycled which results in a typical efficiency for generating linearly polarized light of 70-85 %. Also, special colour filters have been proposed based on chiral-nematic reactive mesogens which increase the efficiency of generating colour. Despite the enormous progress in this field, a need persists for improved methods for generating polarized light and colour based on low cost optical components with a high efficiency. Here, the use of holographic phase gratings is reported for the generation of polarized light and colour. The phase grating are recorded in a photopolymer which is coated onto a backor frontlight for LCDs. Typically the recording is performed in the transmisson mode or in the waveguiding mode and slanted phase gratings are generated with their refractive index modulation at an angle between 20o and 45o with the normal of the substrate. It is shown that phase gratings with a high refractive index modulation and a high efficiency can be generated by a proper selection of the photopolymer and illumination conditions. These phase gratings coupleout linearly polarized light with a high contrast (> 100) and the light is directed directly to the LCD/viewer without the need for redirection foils. Dependent on the type of phase grating, the different colours are coupled-out at a slightly different angle which potentially increases the efficiency of classical colour filters. Moreover, the phase gratings are completely transparent in direct view which opens the possibility to use them in frontlights for LCDs. Holographic polarization gratings posses a periodic pattern in the polarization state of light (and not in the intensity of light). A periodic pattern in the polarization direction of linearly polarized light is obtained upon interference of two circularly polarized laser beams. In the second part of the lecture, it is shown that these periodic polarization patterns can be recorded in a linear photo-polymerizable polymer (LPP) and that such an alignment layer induces a period rotation in the director of (reactive and non-reactive) liquid crystals. By a proper design, optical components can be produced with only first order diffraction and with a very high efficiency (>0.98). It is shown that these diffraction gratings are potentially useful in projection displays with a high brightness and energy efficiency

• Journal of Digital Convergence
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• v.18 no.2
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• pp.235-247
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• 2020

The Mutual Financial Cooperatives(MFCs) in Korea need to make efforts to increase efficiency and productivity in order to secure stable and sustainable growth and competitiveness. Therefore, this study analyzes the efficiency and productivity of MFCs from 2012 to 2018 and suggests some implications. The methodology employed is a Dynamic-Network Slacks-Based Measure(DNSBM) Model. The findings from an empirical study include that first, on average efficiency scores of the institutions, NH(0.225) showed the highest overall efficiency, and followed by SH(0.128) and MG(0.126). After 2015, most of the MFCs' efficiency scores had risen until to 2018. Second, in divisional analysis, the inefficiency in creating the high profitability-stage had been greater than establishing-funds-stage. Third, in projection analysis of Division 2, the inefficiency of the output factors such as interest income and operating income was severe. Fourth, the results from the Malmquist Productivity Index analysis of Division 1 of the fist-stage illustrate that all three MFCs showed minus catch-up effects. Also, a soundness from reducing bad loans and expansion of loans in combination with generating various ways of creating profits besides the interest income is urgently needed for Korean MFCs.