• Journal of Environmental Science International
• /
• v.14 no.11
• /
• pp.1049-1056
• /
• 2005

[ $NO_2$ ] concentration characteristics of Busan metropolitan city was analysed by statistical method using hourly $NO_2$ concentration data$(1998\~2000)$ collected from air quality monitoring sites of the metropolitan city. 4 representative regions were selected among air quality monitoring sites of Ministry of environment. Concentration data of $NO_2$, 5 air pollutants, and data collected at AWS was used. Both Stepwise Multiple Regression model and ARIMA model for prediction of $NO_2$ concentrations were adopted, and then their results were compared with observed concentration. While ARIMA model was useful for the prediction of daily variation of the concentration, it was not satisfactory for the prediction of both rapid variation and seasonal variation of the concentration. Multiple Regression model was better estimated than ARIMA model for prediction of $NO_2$ concentration.

• Journal of information and communication convergence engineering
• /
• v.6 no.4
• /
• pp.430-433
• /
• 2008

A merged altimeter data products are used to estimate sea level variation in the East Sea between 1993 and 2006. The altimeter data show a high correlation coefficient (0.85) after applying gaussian low pass filter for 180days at Ulleung island. The both of Mukho coast and Ulleung island are minimal sea level in March to May and maximal in September to November. Sea level of Mukho coast is higher than that of Ulleung island during March to May, while Mukho coast is lower during September to November because the North Korea Cold Current flows along the coast line of Mukho. Generally sea level variation at Mukho coast and Ulleung island associated with seasonal variations.

• Journal of Korean Society for Atmospheric Environment
• /
• v.11 no.3
• /
• pp.253-262
• /
• 1995

A study has been performed on the characteristics of rural and urban surface ozone concentration for the period of March 1992 to February 1993. The monitoring station of rural ozone is located at Kosan, Cheju and other urban monitoring stations are located at Seoul, Pusan and Kwangju. Rural's and urban's ozone data exhibit a distinct features in many ways. First, annual mean of rural ozone concentration os very high(42 ppbv) but urban's are very low(10 .sim.15 ppbv). Second, rural ozone data shows a seasonal variation with it's maximum in spring, and minimum in summer, but urban's show a seasonal variation with it's maximum in spring, and minimum in winter. Third, diurnal variation of rural data is very small but that of urban's are very large. Fourth, urban's data are extremely low(< 3 ppbv) and have no seasonal variations.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.2
• /
• pp.297-308
• /
• 2010

This article deals with the problem of testing mean when the coefficient of variation in normal distribution is known. We propose Bayesian hypothesis testing procedures for the normal mean under the noninformative prior. The noninformative prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we propose the objective Bayesian hypothesis testing procedures based on the fractional Bayes factor and the intrinsic Bayes factor under the reference prior. Specially, we develop intrinsic priors which give asymptotically same Bayes factor with the intrinsic Bayes factor under the reference prior. Simulation study and a real data example are provided.

• Phonetics and Speech Sciences
• /
• v.9 no.2
• /
• pp.77-83
• /
• 2017

We propose a new method to reduce emotion recognition errors caused by variation in speaker characteristics and speech rate. Firstly, for reducing variation in speaker characteristics, we adjust features from a test speaker to fit the distribution of all training data by using the histogram equalization (HE) algorithm. Secondly, for dealing with variation in speech rate, we augment the training data with speech generated in various speech rates. In computer experiments using EMO-DB, KRN-DB and eNTERFACE-DB, the proposed method is shown to improve weighted accuracy relatively by 34.7%, 23.7% and 28.1%, respectively.

• Communications for Statistical Applications and Methods
• /
• v.31 no.5
• /
• pp.487-496
• /
• 2024

In this paper, we propose a data-driven procedure to segment a binary sequence as an alternative to the popular hidden Markov model (HMM) based procedure. Unlike the HMM, our procedure does not make any distributional or model assumption to the data. To segment the sequence, we suggest to minimize the least square distance from the observations under total variation regularization to the solution, and develop a polynomial time algorithm for it. Finally, we illustrate the algorithm using a toy example and apply it to the Gemini boat race data between Oxford and Cambridge University. Further, we numerically compare the performance of our procedure to the HMM based segmentation through these examples.

• Geophysics and Geophysical Exploration
• /
• v.12 no.2
• /
• pp.208-214
• /
• 2009

Using the GNSS data and tilt-meter data of Boeun (BOEN) and Goesan (GSAN) GNSS stations, we have calculated the differential distance vector variation with the calculation time span set to 1 hour and 3 hour and differential tilt vector variation along time and derived an indicator of similarity between the two variations along time. The similarity such calculated is rather lower than high. But as the existence of a circular type movement of the antenna's phase center's location due to the tilt's variation of the antenna tower because of the sunlight's diurnal change is certain, we recommend to take such diurnal variation of antenna's location into consideration when the correction error in DGNSS or the measured data at reference stations in VRS (Virtual Reference System) is broadcast.

• Health Policy and Management
• /
• v.28 no.1
• /
• pp.15-22
• /
• 2018

Background: Health is affected by various local factors. This study aims to investigate the age-standardized mortality variation of Seoul as well as the characteristics of the factors related to the mortality variation. Methods: The Korea Community Health Survey data, Seoul Survey data, Seoul statistics, and e-regional indicators of the National Statistical Office were used. To investigate the basic boroughs standardized mortality variation in Seoul, external quotient, coefficient of variation (CV), and systematic component of variation (SCV) values were suggested; correlation analysis and multiple regression analysis were conducted to investigate the characteristics related to standardized mortality rate. Results: The highest and the lowest standardized mortality rate of Seoul by boroughs had as much as 1.4 times difference; a low level of variation was shown in CV by 8.2; and was shown in SCV by 79. As a result of the multiple regression analysis of the factors that affect standardized mortality variation, the higher the rate of householders with college or higher, the lower the standardized mortality rate, and the higher the high-risk drinking rate, the higher the standardized mortality rate. Of the two, the rate of householder with a degree equivalent or higher than college was shown to have the biggest impact, followed by high-risk drinking rate. Conclusion: We found a variation in age-standardized mortality rate of boroughs in Seoul. The results suggest that policy makers should take into account socioeconomic environmental characteristics of community in developing community-based health promotion rather than focusing on lifestyle changes of residents.

• Journal of the Korean earth science society
• /
• v.30 no.6
• /
• pp.683-691
• /
• 2009

Geomagnetic variation around May 2, 2009 when Angdong earthquake broke out was analyzed using the data recorded at the Cheong-yang geomagnetic observatory, KMA. Firstly, we predict the geomagnetic variation by PCA analysis of geomagnetic data, and then compare the predicted value with the observed data to find any significant differences in residuals. Secondly, wavelet semblance technique is applied to compare the time series before and after the earthquake. Some meaningful change is detected in the Z-field. Thirdly, eigen value analysis for the 3 component geomagnetic data is performed. The location of the observatory was too far from the epicenter and the magnitude was too small to find decisive precursory phenomenon. Nevertheless we can detect some significant correlation between the earthquake and the variation of the geomagnetic field. Various signal processing methods applied in this study will give some opportunity to find precursory effects in the future.

• International journal of advanced smart convergence
• /
• v.3 no.1
• /
• pp.15-19
• /
• 2014

This study was compared the variation system of body posture condition for stability by the posture. We used a model of bio parameter on the basis of the move state in the standing posture. We compared the sway movement derived from average of the physical sensing condition. Vision condition of variation average (Vi-${\sigma}_{AVG-AVG}$) was verified slightly greater at $13.746{\pm}4.05$ unit. Vestibular condition of variation average (Ve-${\sigma}_{AVG-AVG}$) was verified slightly larger at $7.829{\pm}1.071$ unit. Somatosensory condition of variation average (So-${\sigma}_{AVG-AVG}$) was verified slightly smaller at $2.592{\pm}0.538$ unit. CNS condition of variation average (C-${\sigma}_{AVG-AVG}$) was verified slightly larger at $0.46{\pm}0.105$ unit. The valuation system will be to deduce the model of body management with falling and stroke and all that sort of things. There will be to infer a data algorithm and the evaluation of processing system.