• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.69-74
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• 2003

GPS/Meteorology technique for PWV monitoring is currently actively being researched an advanced nation. But, there is no detailed research on an evaluation of precision of GPS derived PWV measurements during the period of foul weather condition. Here, we deal with the precision of GPS derived PWV during the passage of Typhoon RUSA. Typhoon RUSA which caused a series damage was passed over in Korea from August 30 to September 1, 2002. We compared th tropospheric wet delay estimated from GPS observation and radio-sonde data at four sites(Suwon, Kwangju, Taegu, Cheju). The mean standard deviation of PWV differences at each site is ${\pm}$0.005mm. We also obtained GPS PWV at 13 GPS permanent stations(Seoul, Wonju, Seosan, Sangju, Junju, Cheongju, Taegu, Wuljin, Jinju, Daejeon, Mokpo, Sokcho, Jeju). GPS PWV time series shows, in general, peak value before and during th passage of RUSA, and low after the RUSA. GPS PWV peak time at each station is related to the progress of a typhoon RUSA. We obtained very similar result as we compare GMS satellite image with tomograph using GPS PWV and we could present th possibility of practical use by numerical model for weather forecast.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.1
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• pp.9-17
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• 2003

Typhoon RUSA, which caused serious damage was passed over in Korea peninsula during 30 August to 1 September, 2002. We estimated tropospheric wet delay using GPS data and meteorological data during this period. Integrated Water Vapor(IWV) gives the total amount of water vapor from tropospheric wet delay and Precipitable Water Vapor(PWV) is calculated the IWV scaled by the density of water. We obtained GPS PWV at 13th GPS permanent stations(Seoul, Wonju. Seosan, Sangju, Junju, Cheongju, Taegu, Wuljin, Jinju, Daejeon, Mokpo, Sokcho, Jeju). We retrieve GPS data hourly and use Gipsy-Oasis II software and we compare PWV and precipitation. GPS observed PWV time series demonstrate that PWV is, in general, high before and during the occurrence of the typhoon RUSA, and low after the typhoon RUSA. GPS PWV peak time at each station is related to the progress of a typhoon RUSA. We got very near result as we compare GMS Satellite image with tomograph using GPS PWV and we could present practical use possibility by numerical model for weather forecast.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.378-387
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• 2016

This study sought to investigate interrelationships and differences of brachial-ankle pulse wave velocity (baPWV), body composition and cardiovascular variables between genders who have been exercised or not in elderly. One hundred fifty participants were classified four groups. Especially out of variables, in male elderly group who had participated in exercise program the PWV range were significantly correlated with muscle mass (r=0.357, p=0.026), SBP (r=0.468, p=0.003), right baPWV (r=0.406, p=0.010), and left baPWV (r=0.333, p=0.038). In male elderly group who had not participated in exercise program, the PWV range were significantly correlated with heart rate (r=0.395, p=0.014), right baPWV (r=0.598, p=0.000), and left baPWV (r=0.602, p=0.000). In female elderly group who had participated in exercise program, the PWV range were significantly correlated with name of diagnosis (r=0.321, p=0.044), SBP (r=0.399, p=0.011), DBP (r=0.545, p=0.000), right baPWV (r=0.648, p=0.000), and left baPWV (r=0.676, p=0.000). In female elderly group who had not participated in exercise program, the PWV range were significantly correlated with age (r=0.471, p=0.003), right baPWV (r=0.836, p=0.000), and left baPWV (r=0.801, p=0.000). The PWV among four groups were not significant different after experiment. However, there were significant differences in the waist/hip ratio (F=9.197, p=0.000), muscle mass (F=74.295, p=0.000), and %fat (F=35.045, p=0.000) from body composition. And there were significant differences in the SBP (F=3.525, p=0.017) after experiment. In conclusion, these data show that regular exercise is associated with arterial compliance (PWV range, right or left PWV) and differed from genders. In other words, this paper may support the concept that regular exercise program may exert a protective effect on arterial compliance, body composition and cardiovascular systems.

• Journal of Astronomy and Space Sciences
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• v.29 no.3
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• pp.295-303
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• 2012

In this study, we compared the precipitable water vapor (PWV) data derived from the radiosonde observation data at Sokcho Observatory and the PWV data at Sokcho Global Positioning System (GPS) Observatory provided by Korea Astronomy and Space Science Institute, for the years of 2006, 2008, 2010, and analyzed the radiosonde seasonal, diurnal bias according to radiosonde sensor types. In the scatter diagram of the daytime and nighttime radiosonde PWV data and the GPS PWV data, dry bias was found in the daytime radiosonde observation as known in the previous study. Overall, the tendency that the wet bias of the radiosonde PWV increased as the GPS PWV decreased and the dry bias of the radiosonde PWV increased as the GPS PWV increased. The quantitative analysis of the bias and error of the radiosonde PWV data showed that the mean bias decreased in the nighttime except for 2006 winter, and in comparison for summer, RS92-SGP sensor showed the highest quality.

• The Journal of Korean Obstetrics and Gynecology
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• v.23 no.1
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• pp.53-64
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• 2010

Purpose: This study was performed to observe the correlation between Hot flush and pulse wave velocity(PWV), ankle brachial index(ABI) in the Climacteric women. Methods: We studied 63 climacteric women visiting OO hospital from 8th January 2007 to 22nd April 2009. The subjects were categorized in two groups, the hot flush group(37) and normal group(26). For the study, the subjects were selected by excluding the patients who receive treatment affect hot flush or have disease affect arterial states. We assessed PWV and ABI of two groups by Oscillometric method using VS-1000(Form PWV/ABI; Fukuda Denshi, Co., Ltd., Japan). From these results, we studied the correlation between hot flush and PWV/ABI by Wilcoxon Mann Whitney Test. Results: 1. It is shown that hot flush group was no significant correlation with normal group. There is no significant factor among R-PWV, L-PWV, R-ABI, L-ABI. However, L-ABI have shown relatively higher correlation with comparison to the other factors.(p-value<0.05) 2. R-PWV, L-PWV significantly increased in menopause group than in premenopause group though there is no relation to the hot flush. (p-value<0.01) Conclusion: Though the results showed no correlations between Hot flush and PWV/ABI in the Climacteric women, L-ABI showed relatively higher correlation with hot flush than others. R-PWV, L-PWV showed significant correlation between premenopause and menopause.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.87-95
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• 2015

In this study, the temporal and spatial variation in precipitable water vapor (PWV) was analyzed for typhoon Ewiniar which had made landfall in the Korean peninsula in 2006. To make a contour map of PWV, zenith total delay (ZTD) was calculated using about 60 GPS permanent stations in Korea, and the pressure and temperature data of nearby AWS stations were interpolated and applied to the equation for calculating the PWV. While Typhoon Ewiniar was migrating north from the southern coast to the eastern coast of Korea, the PWV migrated showing a spatial distribution similar to that of rainfall. Also, the fluctuating pattern of the normalized PWV was analyzed, and the moving speed of the PWV was estimated using the delay time of the increase/decrease pattern in the eight-test stations. The result indicated that the moving speed of the PWV was about 35 km/h, which was similar to the average moving speed of the typhoon (38.9 km/h).

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.367-375
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• 2010

In this study, we compared the precipitable water vapor (PWV) data derived from the radiosonde observation data at Sokcho Observatory and the PWV data at Sokcho Global Positioning System (GPS) Observatory provided by Korea Astronomy and Space Science Institute, from 0000 UTC, June 1, 2007 to 1200 UTC, May 31, 2009, and analyzed the radiosonde bias between the day and the night. In the scatter diagram of the daytime and nighttime radiosonde PWV data and the GPS PWV data, dry bias was found in the daytime radiosonde observation as known in the previous study. In addition, for all the rainfall events, the tendency that the wet bias of the radiosonde PWV increased as the GPS PWV decreased and the dry bias of the radiosonde PWV increased as the GPS PWV increased was significantly less distinctive in nighttime than in daytime. The quantitative analysis of the bias and error of the radiosonde PWV data showed that the mean bias decreased in the second year, regardless of nighttime or daytime rainfall, and the non-rainfall root mean square error (RMSE) was similar to that of the previous studies, while the rainfall RMSE was larger to a certain extent.

• The Journal of Internal Korean Medicine
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• v.30 no.3
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• pp.525-533
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• 2009

Objectives : There are lots of reports that cardiovascular disease, including hypertension, cerebro-vascular accident, and coronary heart disease, is related to atherosclerotic changes. Increased serum levels of lipids could play a role in these changes. This study aimed to investigate the relationship between PWV and risk factors of cardiovascular disease, including serum lipid values. Methods : This study included 261 subjects ($49.32{\pm}11.79$ years, 112 male) who underwent PWV and serum lipid evaluation. We investigated the correlation between serum lipid values, blood pressure, body mass index (EMI) and PWV. Pearson's correlation and partial correlation analysis were applied to examine the relationship between PWV and risk factors of cardiovascular disease. Results : Serum triglyceride, total cholesterol, systolic blood pressure, and diastolic blood pressure were significantly correlated with PWV. Partial correlation coefficient adjusted by age yielded significant correlation between serum triglyceride, systolic blood pressure, diastolic blood pressure and PWV. Conclusion : In this study, it seems that there are significant relationships between PWV, triglyceride and blood pressure. We could suggest that PWV might have some relationships with Dam-eum and blood stasis in oriental theory.

• Spatial Information Research
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• v.18 no.4
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• pp.33-41
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• 2010

Approximately 100 permanent GPS stations are currently operational in Korea. However, only 10 sites have their own weather sensors connected directly to the GPS receiver. Thus. calculation of meteorological data through interpolation of AWS data are needed to determine precipitable water vapors at a specific GPS station without a meteorological sensor. This study analyzed the accuracy of two meteorological data interpolation methods called reverse sea level correction and kriging. As a result, the root-mean square-error of reverse sea level correction were seven times more accurate in pressure and twice more accurate in temperature than the kriging method. For the analysis of PWV accuracy, we calculated GPS PWV during the summer season in :2008 by using GPS observation data and interpolated meteorological data by reverse sea level correction. And, we compared GPS PWV s based on interpolated meteorological data with those from radiosonde observations and GPS PWV s based on onsite GPS meteorological sensor measurements. As a result, the accuracy of GPS PWV s from our interpolated meteorological data was within the required operational accuracy of 3mm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.1
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• pp.33-39
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• 2018

As the retrieval accuracy of PWV estimates from GPS measurements is proportional to the accuracy of water vapor WMT, the WMT model is a significant formulation in the conversion of PWV from the GPS ZWD. The purpose of this study is to develop a MWMT model for the retrieval of highly accurate GPS PWV using the radiosonde measurements from six upper-air observing stations in the region of Korea. The values of 1-hr PWV estimated at four GPS stations during one year are used to evaluate the validity of the MWMT model. It is compared to the PWV obtained from radiosonde data that are located in the vicinity of GPS stations. Intercomparison of radiosonde PWVs and GPS PWVs derived using different WMT models is performed to assess the quality of our MWMT model for Korea. The result in this study indicates that the MWMT model is an effective model to retrieve the enhanced accurate GPS PWV, compared to other GPS PWV derived by Korean annual or global WMT models.