• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.119-131
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• 2010

Drought is one of disaster causing factors to produce severe damage in the World because drought is destroyed to the ecosystem as well as to make difficult the economy of the drought area. This study, using Palmer Drought Severity Index carries out correlation analysis with sea surface temperatures. Comparative analysis carries out by calculated Palmer Drought Severity Index and past drought occurrence year. Result of comparative analysis, PDSI indexes were in accord with the past drought. Cluster analysis for correlation analysis carries out using precipitation and temperature that is input datas palmer drought severity index, and the result of cluster analysis was classified as 6. Also, principal component carries out using result of cluster analysis. 14 principal component analyze out through principal component analysis. Using analyzed 14 principal component carries out correlation analysis with sea surface temperature that is delay time from 0month until 11month. Correlation analysis carries out sea surface temperatures and calculated cycle component of the low frequency through Wavelet Transform analysis form principal component. Result of correlation analysis, yang(+) correlation is bigger than yin(-) correlation. It is possible to check similar correlation statistically the area of sea surface temperature with sea surface temperature in the Pacific. Forecasting possibility of the future drought make propose using sea surface temperature.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.30-38
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• 2015

In this study, to improve effectiveness of road management services and the safety of the road in winter, road surface temperature prediction model was developed. We have utilized the existing input data of meteorological data and additional traffic data. This Road surface temperature prediction model was utilizing a Heat-Balance Method additionally considering amount of traffic that produce heat radiation by vehicle-tire friction. This improved model was compared to the based model to check into influence of traffic affecting the road surface temperature. There were verified by comparing the real observed road surface temperature of the third Gyeong-In highway and road surface temperature from the two models. As a result, the error of real observed and the predicted value (RMSE) was found to average $1.97^{\circ}C$. Observed road surface temperature was dramatically affected by the sunlight from 6 a.m. to 2 p.m. and degree of influence decreases after that. The predictive value of the model is lower than the observed value in the afternoon, and higher at night. These results appear due to the shielding of solar radiation caused by the vehicle in the afternoon and at night, the vehicle appeared to cause thermal heat supply.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.680-695
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• 1998

The objective of this study is to optimize the responses of the creep feed ceramic grinding process simultaneously by an off-1ine multicriteria optimization methodology. The responses considered as objectives are material removal rate, flexural strength, normal grinding force, workpiece surface roughness and grinder power. Alumina material was ground by the creep feed grinding mode using superabrasive grinding wheels. The process variables optimized for the above objectives include grinding wheel specification, such as bond type, mesh size, and grit concentration, and grinding process parameters, such as depth of cut and feed rate. A weighting method transforms the multi-objective problem into a single-objective programming format and then, by parametric variation of weights, the set of non-dominated optimum solutions are obtained. Finally, the multi-objective optimization methodology was tested by a sensitivity analysis to check the stability of the model.

• Journal of Information Technology Services
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• v.12 no.4
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• pp.165-174
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• 2013

Log scaling which decides a quality grade of log is influence the price of log at the market. It is the one of important works at the field until now. So it remains using a ruler traditionally. This study evaluated the automating program through compared the automating program with using a ruler for log. The automating program used libraries of OpenCV concerning image processing algorithm to measure log diameter for scaling. In addition, it applies two panels of checkered pattern beside a pile of logs and tapes on the surface of a log diameter to find a correct value. We analyzed statistical mean difference of both log diameter and volume. In conclusion, the automating program after applying check panel and taping ins't different using a ruler. Therefore we need to considerate about applying it for improving Forest Administration.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.12
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• pp.3360-3371
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• 1995

Hydrodynamic characteristics of a stratified flow at a Y-junction were examined analytically. Gas is supplied through the main horizontal channel and liquid is introduced into the gas stream from the Y-shaped bottom branch. Analysis was performed with irrational flow and inviscid fluid assumptions. The Stokes' inverse transformation technique was adopted to convert the real x-y plane into the x-.psi. plane. The potential flow equation was solved numerically in the transformed (x-.psi.) plane and the interface profile, pressure distribution and the streamlines were obtained. The effects of the inlet conditions, injection angle and the gravity on the flow characteristics were also examined. To check the validity of the present method, the previous resultant the two-dimensional obtuse wedge flow was compared. The inverse transformation technique turned out to be also very useful to predict the hydrodynamic characteristics of a stratified flow with the pressure variation at a Y-shaped mixing junction.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.52.1-52.1
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• 2013

We present new analyses of FLS 1718+59, a galaxy-galaxy gravitational lens system in the Spitzer First Look Survey (FLS) Field. A background galaxy (z = 0.245) is severely distorted by a nearby elliptical galaxy (z = 0.08), which can be interpreted as a result of gravitational lensing. We analyze this system by multiple methods, including ELLIPSE fitting, gravitational lens modeling, and surface brightness fitting. From this analysis, we obtain parameters of the lens galaxy using varying approaches and compare them. In the future, we will conduct SED fitting for the lens galaxy and estimate the stellar mass, and compare this with the total mass of the lens to check the M-L relation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.982-990
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• 2000

The finite element alternating method is extended further for general three dimensional cracks in an isotropic body subjected to the mode I loading. The required analytical solution for a dime dimensional crack in an infinite isotropic body is obtained by solving the integral equations. In order to remove the high singularity in integration, the technique suggested by Keat et al. was used. With the proposed method several example problems are solved in order to check the accuracy and efficiency of the method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1391-1394
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• 2007

In order for Hypoid gear development. Gears are required to sustain heavy loads or on applications where the gear box is made or a material with a different coefficient of thermal expansion form that or the gears and shafts, it is desirable to make a deflection and contact check under load. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.582-594
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• 2012

A simple ecohydorlogic model that simulates hydrologic components and vegetation dynamics simultaneously based on equations of soil water dynamics and vegetation's growth and mortality is discussed. In order to simulate ungauged watersheds, the proposed model is calibrated with indirected estimated observation data set; 1) empirically estimated annual vaporization, 2) monthly surface runoff estimated by NRCS-CN method, and 3) vegetation fraction estimated by SPOT/VEGETATION NDVI. In order to check whether the model is performed well with indirectly estimated data or not, four upper dam watersheds (Andong, Habcheon, Namgang, Milyang) in Nakdong River watershed are selected, and the model is verified.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.7-13
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• 1999

The potential for growth and the future impact of Rapid Prototyping that it will have on the product development cycle are enormous. Since making tools, precedes making parts, Rapid Tooling becomes widely used in automobile, aerospace, electronic, and other industries. In this study, master models formed by Rapid Prototyping of Stereolithography have been applied for vacuum casting to obtain silicone patterns which have transformed into epoxy models. The epoxy models have been measured to check dimension errors, and tested their functions. These checking and measurement have provided information on plastic injection possibilities and data for die design, Temporary die making with the materials of Aluminum/Epoxy and powder injection metal (PIM) has also been discussed in terms of hardness, surface roughness, and SEM microstructures.