• Journal of Korea Water Resources Association
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• v.48 no.5
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• pp.357-365
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• 2015

Both exponents of distance and elevation into distance-and-elevation ratio method for estimating missing rainfall data are expressed as squares together but in this study the two exponents are differently separated and analyzed. We used 326 hourly rainfall events of precipitation data during 10 years of 2004 to 2013 observed at a base station of Pyeongchang and the five neighboring index stations-Bangrim, Suju, Cheongoksan, Jinbu, Yeongwol1-in Han River basin for a case study. As a result, exponent values of distance and elevation appropriate for a topography of the site appear as 3.7 and 0.57 respectively. The exponents of distance and elevation difference need to be applied according to topographical characteristics of site where estimating missing data or interpolation are required.

• Journal of the Korean Solar Energy Society
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• v.37 no.6
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• pp.79-91
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• 2017

The meteorological data of 1 hour interval are required to write a typical weather data for building energy simulation. However, many meterological data are missing and the interpolation method to recover the missing data is required. Especially, lots of meterological data are replicated by linear interpolation method because the changes are not significant. While, the wind velocity fluctuates with the time or locations, so linear interpolation method is not appropriate in interpolation of the wind velocity data. In this study, three interpolation methods, using surrounding wind velocity data, Inverse Distance Weighting (IDW), Revised Inverse Distance Weighting (IDW-r), were analyzed considering the characteristics of wind velocity. The Revised Inverse Distance Weighting method, proposed in this study, showed the highest reliability in restoration of the wind velocity data among the analyzed methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.4
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• pp.329-341
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• 2011

The object of this paper is to compare the accuracy and the characteristic of various methods of solving the geodetic inverse problem for the geodesic lines which be in the standard case and special cases(antipodal, near antipodal, equatorial, and near equatorial situation) on the WGS84 reference ellipsoid. For this, the various algorithms (classical and recent solutions) to deal with the geodetic inverse problem are examined, and are programmed in order to evaluate the calculation ability of each method for the precise geodesic determination. The main factors of geodetic inverse problem, the distance and the forward azimuths between two points on the sphere(or ellipsoid) are determined by the 18 kinds of methods for the geodetic inverse solutions. After then, the results from the 17 kinds of methods in the both standard and special cases are compared with those from the Karney method as a reference. When judging these comparison, in case of the standard geodesics whose length do not exceed 100km, all of the methods show the almost same ability to Karney method. Whereas to the geodesics is longer than 4,000km, only two methods (Vincenty and Pittman) show the similar ability to the Karney method. In the cases of special geodesics, all methods except the Modified Vincenty method was not proper to solve the geodetic inverse problem through the comparison with Karney method. Therefore, it is needed to modify and compensate the algorithm of each methods by examining the various behaviors of geodesics on the special regions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.2
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• pp.81-95
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• 2014

In the present study, the statistical analysis on the storm waves in the East Sea have been carried out, and the several storm waves were reproduced by the modified WAM as a first step for the accurate and prompt forecasting and warning against the swell waves in East Sea. According to the present study, the occurrences of the storm waves from the North were the most probable, while the waves from the Northeast were most frequently observed. It was found that the significant wave heights of storm waves from the North and Northern northeast were larger than those of storm waves from the Northeast. But due to long fetch distance, the significant wave periods of storm waves from the Northesast were longer than those of North and Northern northeast. In addition to the wave analysis, the numerical experiments for the storm waves in East Sea were carried out using the modified WAM, and three periods of storm waves in 2013 were calculated. The numerical results were well agreed with wave measurements. However the numerical simulation results in shallow water region showed lower accuracies compared to deep water, which might be due to lower resolution of wind field and bottom topography caused by large grid size, 5 minute, adopted in the present study. Overall computational efficiency of the modified WAM found to be excellent compared to original WAM. It is because the modified WAM adopted the implicit scheme, thereby the present model performed 10 time faster than original WAM in computation time.

• Tuberculosis and Respiratory Diseases
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• v.61 no.2
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• pp.121-128
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• 2006

Background: The "health-related quality of life" (HRQL) for patients with chronic respiratory disease has been emphasized, because chronic respiratory disease (CRD) is chronic and progressive, and it finally causes disability. HRQL instruments may be useful for monitoring patients' progress or for determining the most appropriate choice of treatment. We describe the adapting St George's Respiratory Questionnaire (SGRQ), which is a self-administered questionnaire developed by Jones et al. (1991), into the Korean version for covering three domains of health for the patients suffering with airways disease. Method: We obtained the original SGRQ from the author after gaining permission. For adaptation, we created an expert panel and translated the original questionnaire into Korean language. The translated questionnaire was then back-translated by bilingual experts and we compared it with the original questionnaire. After correction and feasibility testing, 74 patients with chronic respiratory disease (COPD, asthma, destroyed lung) completed the Korean version of the SGRQ. The clinical status of each patients was evaluated concurrently with measurement of their health status. Result: The Korean version of the SGRQ was acceptable and easy to understand. Cronbach's alpha reliability coefficient was 0.92 for the overall scale and 0.63 for the "Symptoms", subscale, 0.87 for the "Activity", subscale, and 0.89 for the "Impacts" subscales. The correlation coefficients between the overall score and the Borg scale score, oxygen saturation, and forced expiratory volume in one second ($FEV_1$) were 0.52, -0.32 and -0.26, respectively. These results support that the Korean SGRQ was correlated with other measurements. Conclusion: The Korean SGRQ was reliable and valid for patients with chronic respiratory disease, such as COPD, asthma, and destroyed lung. The SGRQ score was well correlated with other respiratory measurements as well. Although further studies should complete the adaptation work, our results suggest that the SGRQ may be used in Korea and also for international studies involving Korean CRD patients.