• Journal of the Mineralogical Society of Korea
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• v.30 no.2
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• pp.71-81
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• 2017

Rock properties and the effects of chemicals that were used for conservation were studied for effective conservation treatment of Seated Buddha rock carving, which is composed of grayish white tuff, at Golguram Hermitage, Gyeongju. The rocks contain 3-5% montmorillonite, a swelling mineral and reacting with water, the d spacing of swelling minerals was increased (1.54-2.69%). On the one hand, the physical properties of the rock samples, such as surface hardness, water absorption rate, and porosity improved after the application of ethyl silicate-based stone strengthener. On the other, the interlayer of swelling minerals decreased and greater the of swelling mineral content, the greater is the extent of swelling (4.23-12.12%). When the ethyl silicate-based stone strengthener was applied after pretreatment with a swelling inhibitor, the physical properties were similar to those of the stone strengthener alone. There was no interlayer spacing change of swelling minerals due to swelling inhibition treatment; however, when the stone strengthener was applied after the swelling inhibitor, interlayer changes were similar to those when only the stone strengthener was treated (4.10-11.85%). Though the peak intensity of swelling minerals in X-ray diffraction pattern decreased, the effect of the swelling inhibitor was almost negligible. Therefore, it is not appropriate to use ethyl silicate-based stone strengthener for Golgulam rock containing swelling minerals and supplementing them with a swelling inhibition system is not effective. Because weathering rapidly progresses when swelling minerals contact moisture, for now, measures to prevent water contact, such as expansion of the canopy, are needed in the lower and side parts of the carving.

• The korean journal of orthodontics
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• v.9 no.1
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• pp.39-65
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• 1979

The purpose of this study was to investigate the pattern of irregularities of teeth in various malocclusion groups. The subjects consist of 803 out-patients (355 males, and 448 females) in department of Orthodontics of S.N.U. Hospital, Yonsei University, and Kyunghi University Hospital. The results were as follows. 1. The proportions of subjects on the basis of Angle's Classification were 39.2% (42.2% male, and 57.8% fomale) in class I malocclusion, 29.0% (44.6% male, and 55.4% female) in class II. div. 1., 3.5%(46.4% male, and 53.6% female) in class II. div. 2., 28.3%(46.3% male, and 53.7% female) in class III. 2. Considering all the subjects, the percentage of teeth crowding was 67.8% (45.0% male, and 55.0% female). In class I malocclusion, the percentage of Crowding was 70.8%(43.5% male, and 56.5% female) with higher frequency in upper anterior teeth than in lower anterior. 3. The percentage of Maxillary anterior diastema was 25.6% (45.6% male, and 54.4% female) on the whole. In class II. div. 1. malocclusion, the percentage was 28.8% (46.3% male, and 53.7% female) and in class III, the percentage was 19.8% (46.7% male, and 53.3% female). Thus, frequency of maxillary anterior distema, was comparatively higher in class II. div. 1. than in class III. 4. The percentage of high canine was 25.1% (53.2% male, and 46.8% female) on the whole, and was 86.0% male and 76.6% female in right side, 73.0% male and 72.3% female in left side. In calss II. div. 2., the percentage was 53.6% (46.7% male, and 53.3% female ). In class II. div. 1., the percentage was 16.7% (46.2% male, and 53.8%) with higher frequency in class II. div.2. 5. The percentage of deep overbite was 23.0% (43. 2% male, and 56.8% female) on the whole. Ia class 11. div. 2., and in clas sll. div. 1., its were 89.3%(48.0% male and 52.0% female), 54.5% (40.9% male, and 59.1% female) respectively. This result can be considered as one of the characterics of Angle's class 11 malocclusion group. 6. The percentage of spacing was 23.0% (36.8% male, and 63.2% female) on the whole, In class II. div. 1., and in class II. div. 2., its were 26.1% (44.3% male, and 55. 7% female), 7.1% (50.0% male, and 50.0% female) respectively. 7. The percentage of open bite was 14.3% (42.6% male, and 57.4% female) on the whole with higher rate on the anterior part. It rated 17.6%(50. 0% male, and 50.0% female) in class III, but none in class II. div. 2. 8. The percentage of crossbite was 22.5% (55.8% male, and 44.2% female) on the whole, with higher frequency on the anterior part than on the posterior part. In Angle's class III, it rated as much as 55.1% (57.6% male, and 42.4% female). 9. The percentage of edge-to-edge bite was 20.4% (47.6% male, and 52.4% female) with higher frequency on anterior part than on posterior part. 10. The percentage of irregularities of teeth in various malocclusion groups, was 21.5% (24.8% maxillary, and 18.1% mandible) in crowding, 20.8% (23.5% maxillary, and 18.0% mandible) in rotation, 10.7% (10.6% maxillary, and 10.8% mandible) in cross bite, 9.5% (11.8% maxillary, and 7.3% mandible) in spacing, 8.5% (8.5% maxillary, and 8.5% mandible) in edge-to-edge bite, 8.1% (8.3% maxillary, 7.8% mandible) in open bite. Crowding teeth, spacing teeth, and rotating teeh were more prevalent in anterior part than in posterior part. Cross bite teeth and edge-to-edge bite teeth were more prevalent in class III malocclusion than in another.

• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.317-322
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• 2006

A polymeric arrayed waveguide grating (AWG) has been proposed and demonstrated by exploiting the nanoimprint method. A PDMS(polydimethylsiloxane) stamp with device patterns engraved was developed out of a master mold made of quartz glass. The device was fabricated by transferring the pattern in the PDMS stamp to a spin-coated polymer film without using any etching process. The device had 8 output channels, while the center wavelengths of each output channel were positioned from 1543.7 nm to 1548.3 nm with the spacing of 0.8 nm. The achieved average channel crosstalk and the 3-dB bandwidth were about 10 dB and 0.8 nm respectively.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.3
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• pp.32-40
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• 1991

A modified transmission line model is proposed for input impedance analysis of a square microstip antenna with single-circularly-polarized. Alog-periodic arrangement with microstrip antenna (LPMA) which consists of 3 resonant element ($3\times1$) is designed for broadband operation ranging from 11.2 GHz to 12.4 GHz, based on this pro- posed model from transmission line model. Aplanar array ($3\times4$array), in which 4sets of the above LPMA are in the same plane, is fabricated for high gain X-band satellite communication antennas. The optimum spacing between each LPMA is determined using computer simulation for the minimum bariation of far field pattern and null. This $3\times4$array has a measured values of gain greater than 8dBi, VSWR les then 2.3, and bandwidth greater than 7% respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.780-786
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• 2015

Social media, such as Social Network Service include a lot of spontaneous opinions from customers, so recent companies collect and analyze information about customer feedback by using the system that analyzes Big Data on social media in order to efficiently operate businesses. However, it is difficult to analyze data collected from online sites accurately with existing morpheme analyzer because those data have spacing errors and spelling errors. In addition, many online sentences are short and do not include enough meanings which will be selected, so established meaning selection methods, such as mutual information, chi-square statistic are not able to practice Emotional Classification. In order to solve such problems, this paper suggests a module that can revise the meanings by using initial consonants/vowels and phase pattern dictionary and meaning selection method that uses priority of word class in a sentence. On the basis of word class extracted by morpheme analyzer, these new mechanisms would separate and analyze predicate and substantive, establish properties Database which is subordinate to relevant word class, and extract positive/negative emotions by using accumulated properties Database.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.203-212
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• 2002

This study was conducted to remove the urban heat island effects embedded in the interpolated surfaces of daily minimum temperature in the Korean Peninsula. Fifty six standard weather stations are usually used to generate the gridded temperature surface in South Korea. Since most of the weather stations are located in heavily populated and urbanized areas, the observed minimum temperature data are contaminated with the so-called urban heat island effect. Without an appropriate correction, temperature estimates over rural area or forests might deviate significantly from the actual values. We simulated the spatial pattern of population distribution within any single population reporting district (city or country) by allocating the reported population to the "urban" pixels of a land cover map with a 30 by 30 m spacing. By using this "digital population model" (DPM), we can simulate the horizontal diffusion of urban effect, which is not possible with the spatially discontinuous nature of the population statistics fer each city or county. The temperature estimation error from the existing interpolation scheme, which considers both the distance and the altitude effects, was regressed to the DPMs smoothed at 5 different scales, i.e., the radial extent of 0.5, 1.5, 2.5, 3.5 and 5.0 km. Optimum regression models were used in conjunction with the distance-altitude interpolation to predict monthly normals of daily minimum temperature in South Korea far 1971-2000 period. Cross validation showed around 50% reduction in terms of RMSE and MAE over all months compared with those by the conventional method.conventional method.

• Tunnel and Underground Space
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• v.9 no.3
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• pp.194-203
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• 1999

The axial stress in rock bolt, the shear stress at the bolt-grout interface and the neutral point are analyzed to understand the mechanical behavior of rook bolt. To analyze the support effects of rock bolt in various geological conditions, numerical analyses are performed with regard to bolt spacing and bolt length in several geological conditions and tunnel sizes. Through the numerical analyses, the distributions of maximum tensile stress and shear stress are determined. And the excavation width of underground opening affects the position of the neutral point. In the circular opening supported by pattern bolting, the increase of confining pressure, the reduction of plastic zone, and that of ground displacement are determined by using the radial stress increase ratio, the plastic zone reduction ratio and the displacement reduction ratio respectively. The results of this study can be applied to a practical tunnel design through understanding of the trends of these support effects.

• Imaging Science in Dentistry
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• v.34 no.2
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• pp.63-67
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• 2004

Purpose: To make a focal trough (image layer) for an average maxillary dental arch of 6-year-old korean in panoramic radiography. Materials and Methods : Phantom for the maxillary dental arch was designed using intercanine width, intermolar width, tooth size, and interdental spacing to record the data of 6-year-old child. The characteristics of pre-corrected panoramic machine (for adult) was evaluated using the phantom, resolution test pattern for margin of the image layer, and metal ball for the center of the image layer. Panoramic image layer of the child was developed by means of decreasing the speed of film-cassette and positioning the phantom backwards, and then the characteristics of post-corrected panoramic machine (for child) were reevaluated. Results: At post-corrected panoramic image layer, beam projection angles at all interdental areas increased for about 2.6-3.8°, the position of the image layer was shifted toward the rotation center for about 2.5 mm at the deciduous central incisior area. The width of image layer decreased at all areas. Conclusion : Increased beam projection angle will reduce the disadvantage of tooth overlap, and the same form between the center of the image layer and dental arch will improve image resolution.

• Atmosphere
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• v.24 no.1
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• pp.101-110
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• 2014

This study estimates and evaluates the daily January temperature from 2003 to 2012 with 30 m-resolution over South Korea, using a modified Parameter-elevation Regression on Independent Slopes Model (K-PRISM). Several factors in K-PRISM are also adjusted to 30 m grid spacing and daily time scales. The performance of K-PRISM is validated in terms of bias, root mean square error (RMSE), and correlation coefficient (Corr), and is then compared with that of inverse distance weighting (IDW) and hypsometric methods (HYPS). In estimating the temperature over Jeju island, K-PRISM has the lowest bias (-0.85) and RMSE (1.22), and the highest Corr (0.79) among the three methods. It captures the daily variation of observation, but tends to underestimate due to a high-discrepancy in mean altitudes between the observation stations and grid points of the 30 m topography. The temperature over South Korea derived from K-PRISM represents a detailed spatial pattern of the observed temperature, but generally tends to underestimate with a mean bias of -0.45. In bias terms, the estimation ability of K-PRISM differs between grid points, implying that care should be taken when dealing with poor skill area. The study results demonstrate that K-PRISM can reasonably estimate 30 m-resolution temperature over South Korea, and reflect topographically diverse signals with detailed structure features.

• Wind and Structures
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• v.26 no.2
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• pp.57-68
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• 2018

Wind tunnel tests are conducted to investigate wake-induced vibrations of two circular cylinders with a center-to-center spacing of 4 diameters and attack angle varying from $0^{\circ}$ to $20^{\circ}$ for Reynolds numbers between 18,000 and 168,800. Effects of structural damping, Reynolds number, attack angle and reduced velocity on dynamic responses are examined. Results show that wake-induced vortex vibrations of the downstream cylinder occur in a wider range of the reduced velocity and have higher amplitudes in comparison to the vortex-induced vibration of a single circular cylinder. Two types of wake-induced instability phenomena with distinct dynamic characteristics are observed, which may be due to different generation mechanisms. For small attack angles like $5^{\circ}$ and $10^{\circ}$, the instability of the downstream cylinder characterizes a one-degree-of-freedom (1-DOF) oscillation moving in the across-wind direction. For a large attack angle like $20^{\circ}$, the instability characterizes a two-degree-of-freedom (2-DOF) oscillation with elliptical trajectories. For an attack angle of $15^{\circ}$, the instability can transform from the 1-DOF pattern to the 2-DOF one with the increase of the Reynolds number. Furthermore, the two instabilities show different sensitivity to the structural damping. The 1-DOF instability can be either completely suppressed or reduced to an unsteady oscillation, while the 2-DOF one is relatively less sensitive to the damping level. Reynolds number has important effects on the wake-induced instabilities.