• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.234-238
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• 2016

Purpose: Increasing use of computer aided design-computer aided manufacturing (CAD-CAM) system and number of design software made design of restoration easy and quick. Outcome of restoration has been dependent on dental technician's wax up proficiency, dentists can design restoration for themselves now. This study aims to investigate the outcome of restoration designs, according to handling skill of CAD-CAM design tool. Materials and methods: A patient's mandibular right 1st molar was prepared. After taking impression, stone model was made, scanned the stone model with 3 shape intra-oral scanner, stereolithography (STL) file was extracted. With 3shape dental designer, one dental technician with more than 5 years work experience (designer 0) and three dental technicians with less than 2years work experience (designer 1, 2, 3-group DT) and 4 1st year residents (designer 4, 5, 6, 7-group RT) designed gold crown on the same STL file. Designed crown's MD (mesio-distal) and BL (bucco-lingual) diameter, height of crown, inter-cuspal distance, number of occlusal contact points were compared. Statistical analysis was carried out, test of normality within each group, using independent t-test. Number of contact points were compared, using Wilcoxon signed-rank test. Results: There was no significant difference between group DT and group RT. Number of contact points also resulted in no significant difference. Conclusion: The outcome of each designed crowns showed no statistical differences, in values which can be expressed as numbers. Subjective factors were different. With increasing proficiency in handling designing software, fabrication of restorations according to each designer's occlusal concept can be made easy.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.563-573
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• 1999

The purpose of this study was to evaluate the availability of computer system for the measurement of tooth size in the model analysis through the comparison of two measurements: One was to use a computer; and the other was to use vernier calipers. Twenty sets of casts were used, which showed a moderate degree of crowding and full eruption of all teeth. The mesio-distal width of 12 teeth from the left central incisor to the left first molar at each set of the casts were measured twice with vernier calipers and a computer respectively. This measurement was repeated two weeks later. First, for the reproducibility analysis, the two computer measurements were compared then the vernier calipers measurements were compared. Second, all the teeth were sepapated into the region of mesiodistal contact points and its width was measured by a micrometer to obtain standard measurements. For the accuracy analysis, these standard measurements were compared with the measurements from the dental casts using two methods. The difference between them was defined as the measurement error. To investigate the cause of measurement error, an examination was made for the presence and degree of contact point deviation on each tooth from the upper and lower occlusograms, and the mesio-distal angulation of each tooth was measured with TARG. Following results were obtained through statistical analysis. 1. In the analysis for reproducibility; the measurements with vernier calipers showed significant differences in three out of twelve teeth while the computer measurements showed significant differences in one out of twelve teeth. 2. In the analysis for accuracy; compared with the standard measurements, the measurements with vernier calipers showed significant differences in three out of twelve teeth while the computer measurements showed significant differences in two out of twelve teeth. 3. Compared with the standard measurements, the measurements with vernier calipers were apt to be larger at the upper first molar, and smaller at the lower first molar The computer measurements, however, were apt to be larger at both upper and lower first molars. 4. The measurements with vernier calipers showed the largest error at the lower first molar and the degree of error was variable according to the tooth while the difference of error was small in the computer measurements. 5. In the analysis for the correlation of the degree of measurement errors with the contact point deviation index and the mesio-distal crown angulation of each tooth, the measurements with vernier calipers did not show significant correlation while the measurements with computer showed slight Positive correlations. The results of this study indicate that a computer system may be useful for the measurement of tooth size in the model analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.131-135
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• 2004

This study was carried out for the analysis of temperature characteristics on soil surface using soil heat flux which is one of the important parameters forming soil temperature. Soil surface temperature was estimated by using the soil temperature measured at 10 cm soil depth and the soil heat flux measured by flux plate at 5 cm soil depth. There was time lag of two hours between soil temperature and soil heat flux. Temperature changes over time showed a positive correlation with soil heat flux. Soil surface temperature was estimated by the equation using variable separation method for soil surface temperature. Arithmetic mean using temperatures measured at soil surface and 10 cm depth, and soil temperature measured at 5 cm depth were compared for accuracy of the value. To validate the regression model through this comparison, F-validation was used. Usefulness of deductive regression model was admitted because intended F-value was smaller than 0.001 and the determination coefficient was 0.968. It can be concluded that the estimated surface soil temperatures obtained by variable separation method were almost equal to the measured surface soil temperature.

• The Korean Journal of Financial Management
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• v.25 no.1
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• pp.1-22
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• 2008

This study is to evaluate, to the extent to, which advanced currency futures and emerging currency futures markets can predict accurately the future spot rate. To this end, Johansen's the maximum-likelihood cointegration method(1988, 1991) is adopted to test the unbiasedness and efficiency hypothesis. Also, this study is to estimate and compare a quantitative measure of relative efficiency as a ratio of the forecast error variance from the best-fitting quasi-error correction model to the forecast error variance of the futures price as predictor of the spot price in advanced currency futures with in emerging currency futures market. Advanced currency futures is British pound and Japan yen. Emerging currency futures includes Korea won, Mexico peso, and Brazil real. The empirical results are summarized as follows : First, the unbiasedness hypothesis is not rejected for Korea won and Japan yen futures exchange rates. This indicates that the emerging currency Korea won and the advanced currency Japan yen futures exchange rates are likely to predict accurately realized spot exchange rate at a maturity date without the trader having to pay a risk premium for the privilege of trading the contract. Second, in emerging currency futures markets, the unbiasedness hypothesis is not rejected for Korea won futures market apart from Mexico peso and Brazil real futures markets. This indicates that in emerging currency futures markets, Korea won futures market is more efficient than Mexico peso and Brazil real futures markets and is likely to predict accurately realized spot exchange rate at a maturity date without risk premium. Third, this findings show that the results of unbiasedness hypothesis tests can provide conflicting finding. according to currency futures class and forecasts horizon period, Fourth, from the best-fitting quasi-error correction model with forecast horizons of 14 days, the findings suggest the Japan yen futures market is 27.06% efficient, the British pound futures market is 26.87% efficient, the Korea won futures market is 20.77% efficient, the Mexico peso futures market is 11.55%, and the Brazil real futures market is 4.45% efficient in the usual order. This indicates that the Korea won-dollar futures market is more efficient than Mexico peso, and Brazil real futures market. It is therefore possible to concludes that the Korea won-dollar currency futures market has relatively high efficiency comparing with Mexico peso and Brazil real futures markets of emerging currency futures markets.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.5
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• pp.57-75
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• 2011

The purpose of this study is to find ways of evaluating the suitability of sites being considered for development of different types of parks in the vicinity of yangmock-myun kyoung buk, where a large project(as large as about14.0$km^2$) has been planned. The results are as follows. Three surveys for selecting the assessment indicators were performed. ${\cdot}$ The first survey analyzed the importance of 23 selected assessment indicators based on a review of existing literature review and an on-the-spot research. ${\cdot}$ The second survey selected assessment indicators for each park type. ${\cdot}$ The third survey computed additive values of selected assessment indicators by the park types. It used a method of standardizing the average importance of indicators by making their sum equal to 10. These additive values were then multiplied by each grade of indicators to make a final evaluation. An evaluation of the site-suitability of park types was performed twice. The purpose of the first evaluation was to figure out how much each type met the minimum requirements targeted for all landscape types. The minimum requirements were derived by using a relative comparison between the standard of value rating of the assessment indicators, which was over the medium magnitude on the importance analysis, and the result of field research. A second evaluation estimated the targeted sites that met the minimum requirements. Value ratings of second assessment indicators were quantitatively divided as 1 to 3 grade and the evaluation scores were added, giving an additive value for each assessment indicator. The evaluation score on each park type was rated on a scale of 1 to 3 according to their averages, (from lowest to highest). Since this evaluation model of the site suitability on park types only focused on the 'face' of space in this study, additional analysis is necessary for setting the evaluation model and incorporating the overall impact of space, network connection and other factors, considering 'spot', 'line' and 'face' aspects of space.

• Herbal Formula Science
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• v.22 no.1
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• pp.167-176
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• 2014

Objectives : This study investigated the improvement effects of Gangjihwan (DF) and combination of Gangjihwan and Gamisochehwan (GSH) on nonalcoholic fatty liver disease in a high fat diet-induced obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into five groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and atorvastatin, DF, and DF+GSH groups given a high fat diet with atorvastatin (10 mg/kg), DF (40 mg/kg), and DF+GSH (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, blood lipid markers, ALT concentrations, liver weight and histology were examined. Results : 1. Body weight gain was significantly decreased in DF, DF+GSH and atorvastatin groups compared with control. The extent of decreases was eminent in DF+GSH group. 2. Circulating concentrations of total cholesterol, HDL-cholesterol and LDL-cholesterol were decreased in DF, DF+GSH and atorvastatin groups compared with control. The decreases were significant in DF+GSH and atorvastatin groups. 3. Liver weights were decreased in DF, DF+GSH and atorvastatin groups compared with control. In particular, liver weight was significantly reduced only in DF+GSH group. 4. Hepatic lipid accumulation was significantly decreased in DF, DF+GSH and atorvastatin groups compared with control, and the magnitude of which was more effective in DF+GSH group than in DF-only group. 5. Circulating ALT concentrations were decreased in DF, DF+GSH and atorvastatin compared with control, but ALS levels were significantly reduced only in DF+GSH group. Conclusions : In conclusion, these results suggest that DF decreases body weight gain, improves blood lipid metabolism, and reduces liver weight and hepatic lipid accumulation, contributing to the improvement of nonalcoholic fatty liver disease. In addition, these effects were more effective in DF+GSH combination group than in DF-only group.

• Herbal Formula Science
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• v.22 no.1
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• pp.113-122
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• 2014

Objectives : This study investigated the improvement effects of Pakistani (DF-a) and Chinese Ephedra herba-containing Gangjihwan (DF-b) on nonalcoholic fatty liver disease in a high fat diet-induced obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into five groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and atorvastatin, DF-a, and DF-b groups given a high fat diet with atorvastatin (10 mg/kg), DF-a (80 mg/kg), and DF-b (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, blood lipid markers, ALT concentrations, liver weight and histology were examined. Results : 1. Body weight gain was significantly decreased in DF-a, DF-b, and atorvastatin groups compared with control. The extent of decreases was eminent in DF-a group. 2. Circulating concentrations of total cholesterol and LDL-cholesterol were significantly decreased in DF-a, DF-b, and atorvastatin groups compared with control. The decreases were most effective in atorvastatin group. 3. Liver weights were decreased in DF-a, DF-b, and atorvastatin groups compared with control. In particular, liver weight was significantly reduced in DF-b group. 4. Hepatic lipid accumulation was significantly decreased in DF-a, DF-b, and atorvastatin groups compared with control, and the magnitude of which was most effective in DF-b group. 5. Circulating ALT concentrations were decreased in DF-a, DF-b, and atorvastatin groups compared with control, but ALS levels were significantly reduced only in DF-b group. Conclusions : In conclusion, these results suggest that DF-a and DF-b decrease body weight gain, improve blood lipid metabolism, and reduce liver weight and hepatic lipid accumulation, contributing to the improvement of nonalcoholic fatty liver disease. In addition, these effects were similar between Pakistani and Chinese Ephedra herba-containing Gangjihwan.

• Korean Journal of Remote Sensing
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• v.30 no.1
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• pp.61-73
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• 2014

This study reviewed an application of water quality estimation using an Airborne Hyperspectral Imagery (A-HSI) and tested a part of Han River water quality (especially suspended solid) estimation with available in-situ data. The estimation of water quality was processed two methods. One is using observation data as downwelling radiance to water surface and as scattering and reflectance into water body. Other is linear regression analysis with water quality in-situ measurement and upwelling data as at-sensor radiance (or reflectance). Both methods drive meaningful results of RS estimation. However it has more effects on the auxiliary dataset as water quality in-situ measurement and water body scattering measurement. The test processed a part of Han River located Paldang-dam downstream. We applied linear regression analysis with AISA eagle hyperspectral sensor data and water quality measurement in-situ data. The result of linear regression for a meaningful band combination shows $-24.847+0.013L_{560}$ as 560 nm in radiance (L) with 0.985 R-square. To comparison with Multispectral Imagery (MSI) case, we make simulated Landsat TM by spectral resampling. The regression using MSI shows -55.932 + 33.881 (TM1/TM3) as radiance with 0.968 R-square. Suspended Solid (SS) concentration was about 3.75 mg/l at in-situ data and estimated SS concentration by A-HIS was about 3.65 mg/l, and about 5.85mg/l with MSI with same location. It shows overestimation trends case of estimating using MSI. In order to upgrade value for practical use and to estimate more precisely, it needs that minimizing sun glint effect into whole image, constructing elaborate flight plan considering solar altitude angle, and making good pre-processing and calibration system. We found some limitations and restrictions such as precise atmospheric correction, sample count of water quality measurement, retrieve spectral bands into A-HSI, adequate linear regression model selection, and quantitative calibration/validation method through the literature review and test adopted general methods.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.1-10
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• 2012

Digital Forecast of the Korea Meteorological Administration (KMA) represents 5 km gridded weather forecast over the Korean Peninsula and the surrounding oceanic regions in Korean territory. Digital Forecast provides 12 weather forecast elements such as three-hour interval temperature, sky condition, wind direction, wind speed, relative humidity, wave height, probability of precipitation, 12 hour accumulated rain and snow, as well as daily minimum and maximum temperatures. These forecast elements are updated every three-hour for the next 48 hours regularly. The objective of this study was to construct Forest Fire Danger Rating Systems on the Korean Peninsula (FFDRS_KORP) based on the daily weather index (DWI) and to improve the accuracy using the digital forecast data. We produced the thematic maps of temperature, humidity, and wind speed over the Korean Peninsula to analyze DWI. To calculate DWI of the Korean Peninsula it was applied forest fire occurrence probability model by logistic regression analysis, i.e. $[1+{\exp}\{-(2.494+(0.004{\times}T_{max})-(0.008{\times}EF))\}]^{-1}$. The result of verification test among the real-time observatory data, digital forecast and RDAPS data showed that predicting values of the digital forecast advanced more than those of RDAPS data. The results of the comparison with the average forest fire danger rating index (sampled at 233 administrative districts) and those with the digital weather showed higher relative accuracy than those with the RDAPS data. The coefficient of determination of forest fire danger rating was shown as $R^2$=0.854. There was a difference of 0.5 between the national mean fire danger rating index (70) with the application of the real-time observatory data and that with the digital forecast (70.5).

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.135-147
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• 2017

We, for the first time, estimated daily and monthly surface nitrogen dioxide ($NO_2$) volume mixing ratio (VMR) using three regression models with $NO_2$ tropospheric vertical column density (OMIT-rop $NO_2$ VCD) data obtained from Ozone Monitoring Instrument (OMI) in Seoul in South Korea at OMI overpass time (13:45 local time). First linear regression model (M1) is a linear regression equation between OMI-Trop $NO_2$ VCD and in situ $NO_2$ VMR, whereas second linear regression model (M2) incorporates boundary layer height (BLH), temperature, and pressure obtained from Atmospheric Infrared Sounder (AIRS) and OMI-Trop $NO_2$ VCD. Last models (M3M & M3D) are a multiple linear regression equations which include OMI-Trop $NO_2$ VCD, BLH and various meteorological data. In this study, we determined three types of regression models for the training period between 2009 and 2011, and the performance of those regression models was evaluated via comparison with the surface $NO_2$ VMR data obtained from in situ measurements (in situ $NO_2$ VMR) in 2012. The monthly mean surface $NO_2$ VMRs estimated by M3M showed good agreements with those of in situ measurements(avg. R = 0.77). In terms of the daily (13:45LT) $NO_2$ estimation, the highest correlations were found between the daily surface $NO_2$ VMRs estimated by M3D and in-situ $NO_2$ VMRs (avg. R = 0.55). The estimated surface $NO_2$ VMRs by three modelstend to be underestimated. We also discussed the performance of these empirical modelsfor surface $NO_2$ VMR estimation with respect to otherstatistical data such asroot mean square error (RMSE), mean bias, mean absolute error (MAE), and percent difference. This present study shows a possibility of estimating surface $NO_2$ VMR using the satellite measurement.