• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.149-154
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• 2017

Detection of rain is one of the essential weather factors that are monitored by automatic weather stations in Korea. In this work, we studied the operation standards required for impedance-based rain detectors in terms of surface temperature and sensitivity, in an effort to establish a qualification procedure for rain detectors. The surface temperature of rain detectors was measured at varying air temperatures from $-30^{\circ}C$ to $20^{\circ}C$, considering the hypothetical presence and absence of rain/snow. In addition, the sensitivity of rain detectors was studied generating artificial raindrops of regular size. The sensitivity was evaluated in terms of the critical number of droplets that triggers the activation of the rain detector. We found that the sensitivity is affected by stationary, horizontal, and vertical droplet deposition methods. The critical number of droplets for the stationary deposition is higher than that for both horizontal and vertical depositions, which provides the maximum limit of droplets required to activate the detector. Based on our experiments considering surface temperature measurements and sensitivity tests, we suggest a revised version of surface temperature and sensitivity requirements for the qualification of impedance-based rain detectors.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.30-40
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• 2011

Numerical simulations were carried out to investigate the impact of SST spatial distribution on the result of air quality modeling. Eulerian photochemical dispersion model CAMx (Comprehensive Air quality Model with eXtensions, version 4.50) was applied in this study and meteorological fields were prepared by RAMS (Regional Atmospheric Modeling System). Three different meteorological fields, due to different SST spatial distributions were used for air quality modeling to assess the sensitivity of CAMx modeling to the different meteorological input data. The horizontal distributions of surface ozone concentrations were analyzed and compared. In each case, the simulated ozone concentrations were different due to the discrepancies of horizontal SST distributions. The discrepancies of land-sea breeze velocity caused the difference of daytime and nighttime ozone concentrations. The result of statistic analysis also showed differences for each case. Case NG, which used meteorological fields with high resolution SST data was most successfully estimated correlation coefficient, root mean squared error and index of agreement value for ground level ozone concentration. The prediction accuracy was also improved clearly for case NG. In conclusion, the results suggest that SST spatial distribution plays an important role in the results of air quality modeling on high ozone episode at coastal region.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.235-241
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• 2014

A ground-based microwave scatterometer has an advantage for monitoring soil moisture content using multi-polarization, multi-frequencies and various incidence angles. In this paper, ground-based multi-frequency (L-, C-, and X-band) polarimetric scatterometer system capable of making observations every 10 min was used to monitor the soil moisture conditions in a corn field over an entire growth cycle. Measurements of volumetric soil moisture were obtained and their relationships to the backscatter observations were examined. Time series of soil moisture content was not corresponding with backscattering coefficient pattern over the whole growth stage, although it increased until early July (Day Of Year, DOY 160). We examined the relationship between the backscattering coefficients from each band and soil moisture content of the field. Backscattering coefficients for all bands were not correlated with soil moisture content when considered over the entire stage ($r{\leq}0.48$). However, L-band Horizontal transmit and Horizontal receive polarization (HH) had a good correlation with soil moisture ($r=0.85^{**}$) when LAI was lower than 2. Prediction equations for soil moisture were developed using the L-HH data. Relation between L-HH and soil moisture shows linear pattern and related with soil moisture content ($R^2=0.77$). Results from this study show that backscattering coefficients of microwave scatterometer appear to be effective to estimate soil moisture content in the field level.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1220-1222
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• 2004

We developed a new device structure using anisotropic phase separation from liquid crystal (LC) and polymer composite materials using UV intensity variation and polymer wetting properties. In the device, the LC molecules are isolated in pixels where LCs are surrounded by the inter-pixel vertical polymer walls and the horizontal polymer films on the upper substrate. These devices show very good mechanical stability against external pressure. The electro-optic characteristics and the mechanical stability of the devices are discussed in view of the flexible display applications.

• Proceedings of the CALSEC Conference
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• 2001.02a
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• pp.11-30
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• 2001

Session Agenda ㆍ E-Business Economy - B2B · What is C-Commerce？ - Marketplace or Businessplace？ ㆍ C-Commerce Business Models - Horizontal, Industry, Private ㆍ C-Commerce via Exchange Solution Models - Marketplace Exchange - Supply Chain Exchange - Product Development Exchange ㆍ Integration is key... NOT Functionality(omitted)

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.604-605
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• 2005

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.35.1-35.10
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• 2019

Pulp revascularization is an alternative treatment in immature traumatized teeth with necrotic pulp. However, this procedure has not been reported in horizontal root fractures. This is a case report of a 9-year-old patient with multiple horizontal root fractures in 2 upper central incisors that were successfully treated with pulp revascularization. The patient presented for treatment 2 years after the initial trauma, and revascularization was attempted after the initial treatment with calcium hydroxide had failed. Prior to pulp revascularization, cone-beam computed tomography and autoradiograms demonstrated multiple horizontal fractures in the middle and apical thirds of the roots of the 2 affected teeth. Revascularization was performed in both teeth; platelet-rich plasma (PRP) was used in one tooth (#11) and the conventional method (blood clot) was used in the other tooth (#21). Clinical and radiographic follow-up over 4 years demonstrated pulp calcification in the PRP-treated tooth. Neither of the 2 teeth were lost, and the root canal calcification of tooth #11 was greater than that of tooth #21. This case suggests that PRP-based pulp revascularization may be an alternative for horizontal root fractures.

• Journal of the Korean Geotechnical Society
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• v.31 no.6
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• pp.5-13
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• 2015

Micropile was mainly used as one of underpinnig methods, and recently has been used for the various purposes such as foundation for new structure or slope stability etc. However, despite of the increase of the usage of micropile, studies about the horizontal bearing characteristic of micropile are insufficient. Thus the model test has been conducted to investigate the horizontal bearing characteristics of micropile with the length ratio and installation angle of pile. Consequently, micropiles at the installation angle of $+30^{\circ}$ and $-30^{\circ}$ effectively increase the horizontal bearing capacity, respectively for L/d ${\leq}25$ and L/d > 50.

• Journal of the Korean earth science society
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• v.36 no.2
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• pp.158-170
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• 2015

This study evaluates the wind speed forecast near the surface layer using the Weather Research Forecasting with Large Eddy Simulation (WRF-LES) model in order to compare the planetary boundary layer (PBL) parameterization with the LES model in terms of different spatial resolution. A numerical simulation is conducted with 1-km and 333-m horizontal resolution over the Gangwon Province including complex mountains and coastal region. The numerical experiments with 1-km and 333-m horizontal resolution employ PBL parameterization and LES, respectively. The wind speed forecast in mountainous region shows a better forecast performance in 333-m experiment than in 1-km, while wind speed in coastal region is similar to the observation in 1-km spatial resolution experiment. Therefore, LES experiment, which directly simulates the turbulence process near the surface layer, contributes to more accurate forecast of surface wind speed in mountainous regions.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.91-98
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• 2013

Shale gas is in the limelight as one of the new energy sources under the circumstances of unstable energy supply and high energy consumption. It is expected to change dynamics of global energy markets due to its abundant resources and global distribution. Shale gas extraction process consists of drilling, fracturing and production. We have surveyed the technologies required for shale gas developments such as a horizontal drilling, a hydraulic fracturing and so on, the environmental issues occurred during the development, the additional technologies to solve the environmental problems and the current research and developments status.