• Journal of Korea Water Resources Association
• /
• v.51 no.5
• /
• pp.395-404
• /
• 2018

This research evaluated the change in rainfall quantile during S1, S2, and S3 by using Representative Concentration Pathways (RCP) 4.5 climate scenario HadGEM3-RA Regional Climate Model (RCM) produced by downscaling and bias correlation compared to the past standard observation data S0. Also, the maximum flood peak volume and flood area were calculated by using the urban runoff model and the impact of climate change was analyzed in each period. For this purpose, Gumbel distribution was used as an appropriate model based on the method of maximum likelihood. As a result, in the case of the 10 year-frequency which is the design of most urban drainage facilities, the rainfall quantile is in increased about 10% if we assume 50 years from now with the $3^{rd}$ quarter value and about 20% if we assume 70 years from now. This result implies that the installed urban drainage facility based on the currently set design flood volume cannot be met the design criteria in the future. Therefore, it is necessary to reflect future climate conditions to current urban drainage facilities.

• Korean Journal of Social Welfare
• /
• v.35
• /
• pp.51-83
• /
• 1998

This study is designed to find out the determinants of housewives' caregiving behavior to their elderly parents-in-law. For this purpose, a tentative path model, constructed with major socio-demographic variables in the caregiver's family as exogenous variables, is proposed to account for caregiver's behavior to elderly parents-in-law. The model is estimated with data collected from a probability sample of housewives in Kwangju, Korea. Estimation of the model, separately for caregiver's fathers-in-law and mothers-in-law, in terms of maximum likelihood(ML) procedures in LISREL8 reveals that housewives' educational attainment, father-in-law's age, father-in-law's health status, and family size have statistically significant causal. effects on care giving behavior to fathers-in-law, and that housewives' educational attainment, mother-in-law's age, family size, and caregiving attitude have significant causal effects on caregiving behavior to mothers-in-law. Comparison of the two estimated models indicates caregiver's educational attainment, caretaker's age, and family size are prominent determinants of caregiving behavior that can be commonly generalized to the two models. Except for these common determinants, however, a nonnegligible amount of differences is identified between the two models. The findings are discussed and interpreted with suggesting some salient theoretical and policy implications.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.3
• /
• pp.141-149
• /
• 2005

Tn general. Gaussian mixture model (GMM) is used to estimate the speaker model from the speech for speaker identification. The parameter estimates of the GMM are obtained by using the Expectation-Maximization (EM) algorithm for the maximum likelihood (ML) estimation. However the EM algorithm has such drawbacks that it depends heavily on the initialization and it needs the number of mixtures to be known. In this paper, to solve the above problems of the EM algorithm. we propose an EM algorithm with the initialization based on incremental ${\cal}k-means$ for GMM. The proposed method dynamically increases the number of mixtures one by one until finding the optimum number of mixtures. Whenever adding one mixture, we calculate the mutual relationship between it and one of other mixtures respectively. Finally. based on these mutual relationships. we can estimate the optimal number of mixtures which are statistically independent. The effectiveness of the proposed method is shown by the experiment for artificial data. Also. we performed the speaker identification by applying the proposed method comparing with other approaches.

• Journal of Broadcast Engineering
• /
• v.28 no.1
• /
• pp.145-148
• /
• 2023

Open-loop Octonion space-time block code for 4 transmit antenna system is considered and random phases are applied to 4 transmit antennas for physical layer security. When an illegal hacker estimates the random phases of 1 through 4 transmit antennas with maximum likelihood (ML), this letter analyzes the bit error rate (BER) performances versus signal-to-noise ratio (SNR). And the Octonion code in the literature[1] does not have full orthogonality so, this letter employs the perfect orthogonal Octonion code. When the hacker knows that the random phases are 2-PSK constellations and he should estimate all the 4 random phases, the hacking is impossible until 100dB. When the hacker possibly know that some of the random phases, bit error rate goes down to 10^-3 so, the transmit message could be hacked.