• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.867-878
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• 2014

Due to the nature of weather radar, blank areas occur due to impediments to observation, such as the ground clutter. Radar beam blockages have resulted in the underestimation rainfall amounts. To overcome these limitations, this study developed the Hybrid Scan Reflectivity (HSR) technique and compared the HSR results with existing methods. As a result, the HSR technique was able to estimate rainfalls in areas from which no reflectivity information was observable using existing methods. In case of estimating rainfalls depending on reflectivity scan techniques and beam-blockage/non beam-blockage, the HSR accuracy is superior. Furthermore, rainfall amounts derived from each method was inputted to the HEC-HMS to examine the accuracy of the flood simulations. The accuracy of the results using the HSR technique in contrast to the RAR calculation system and M-P relation was improved by 7% and 10%(based on correlation coefficients), and 18% and 34%(based on Nash-Sutcliffe Efficiency), on average, respectively. Therefore, it is advised that the HSR technique be utilized in the hydrology field to estimate flood discharge more accurately.

• Publications of The Korean Astronomical Society
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• v.11 no.1
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• pp.109-123
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• 1996

We have developed a 5GHz continuum receiver system. The receiver is a direct type receiver. In order to reduce the noise due to the fluctuation of the gain in the amplifiers, the system employs the Dicke switching method. We made the 5GHz low-noise amplifier and the bandpass filter. The low-noise amplifier gives ${\sim}35dB$ gain and has ${\sim}210K$ noise temperature. The bandpass filter has a passband between 4.3 and 5.4GHz. We also made switch driver, video amplifiers, phase detector, and integrator. Using a 1.8 meter offset parabolic antenna, we measured the efficiency of the system. Since the antenna does not have a driver to track objects, observations were performed with the antenna fixed. The measured noise temperature of the system is ${\sim}650K$. From the observation of the blank sky, noise level was measured. It was found that the systematic noise(${\sim}0.5K$: peak to peak value) is much larger than the thermal noise. The systematic noise is possibly related to the stability of the DC power supplied to the receiver system. Besides the noise of the system, it was found that the airplanes are the very serious noise sources. We measured the radio flux of the Sun using the developed system. The observed radio flux of the Sun is ${\sim}10^6Jy$, which is close to the known value of the quiet Sun. The test observation of the Sun shows that the angular beam size of the antenna is ${\sim}2.2^{\circ}$.

• Journal of Gifted/Talented Education
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• v.11 no.2
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• pp.127-150
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• 2001

The upcoming century is a knowledge based society which did not exist before which requires creative ability to solve problems. Therefore, it is necessary to Provide a creative program of problem solution in order to match this global trend The creativity of problem solution means the ability to solve a problem using previous ideas in an advanced way or develop new ideas. Creative education is especially important for infants. Because the young mind is where fresh ideas preside and can frame-work the early stage of life like a blank sheet of paper. The Infant-Early Child Creative Development Institute. as an adhesive institute at Yeungjin College, develops various programs that integrate methods which match current trend in this era and also start the Creative Promotion Test with 2,000 Families for the expansion of creative education from the baseline as an alternative method. The infants tested in the creative test will find ways of problem solution through animation beam projects for their given situation and also discuss the problems with their family members. Through these processes the infant and family members will complete the creative structures to solve the problems using limited materials given by the institute, and the final product will be evaluated as objective results. The final evaluation of the test will also be considered the teamwork of family cooperation and the attitudes of participants as well as the product of problem solution. The criterion of the evaluation is to be considered both a creative way of thinking and creative attitudes. Because the score counts were conducted manually it delayed the selection of awarded students who took the test. Also, we found that some parents have difficulty in accessing information to find the score through homepage from the computer. this Problem might be corrected in the future plan. Like Freud's saying, if human character and exploring attitudes during the early stage of a child, a person's creativity is composed their infant period as their basic foundation. Therefore, the family wh first environment the infant encounters will be treated as a prima when making basic structure. From this viewpoint, this creative test work as a festival of creativity fare with 2,000 families.