• 한국멀티미디어학회논문지
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• 제10권9호
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• pp.1220-1228
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• 2007

본 논문에서는 기존의 서명 비교방법인 픽셀비교 (point-to-point) 방식과 부분비교(segment-to-segment) 방식의 단점을 보완한 효율적인 온라인 서명 인증 방법을 제안한다. 기존의 연구에서는 각각의 비교 방식에 알맞은 특징들이 추출되어서 서명 인증 시스템이 구현되어 왔었다. 본 논문에서는 두 비교방식의 장점을 결합하였다. 제안된 기법은 서명의 제적방향이 변화되는 지점인 변곡점을 이용해서 서명을 비교하고, 학습을 통하여 진서명간의 유사도는 높이고 진서명과 위조서명간의 상이도를 높이는 필자고유특징을 찾아낸다. 본 논문에서 제안된 방식을 사용한 경우, 필자고유특징을 사용하지 않는 경우와 비교해서 서명 인증율이 96.33%로 향상되었다.

• 대한수학회보
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• 제36권3호
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• pp.609-619
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• 1999

IN this note we study more about the omitted are for the extremal functions and its {{{{ {π } over {4 } }}}}-property based upon Schiffer's variational method and zBrickman-Wilken's result. we give an example other than the Koebe function which is both a support point of S and the extreme point of HS. Furthermore, we discuss the relations between the support points and the L wner chain.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.467-470
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• 1994

In this paper, we develop two sufficient conditions for Schur stability of convex combinations of discrete time polynomials. We give conditions under which Schur stability of the extremes implies Schur stability of the entire convex combination. These results are based on Bhattacharyya's result(1991), the AHMC theory in Barmish and Kang's paper (1993) and the bilinear transformation. Important applications of the results involves robust Schur stability of a feedback system having degenerate interval plants in an extreme point context.

• Journal of the Korean Data and Information Science Society
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• 제24권4호
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• pp.857-865
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• 2013

집중 호우로 인한 피해가 증가하면서 다양한 기법들을 이용하여 강우량 예측에 대한 관심이 높아졌다. 최근에는 극단분포를 활용하여 강우량을 예측하려는 시도가 늘고 있다. 본 연구에서는 일반화 극단 분포를 활용하여 실제 서울시의 1973년부터 2010년까지 7월달의 사후예측분포를 생성하고, 수치적인 계산을 위해서 MCMC (Markov chain Monte Carlo)알고리즘을 활용하였다. 이 연구를 통해서 사후예측분포의 점추정값들을 비교하였고 2011년 7월달의 자료와 비교해 봤을 때 집중 호우의 확률이 증가한 것을 알 수 있었다.

• Journal of the Korean Data and Information Science Society
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• 제25권3호
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• pp.643-653
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• 2014

In this paper, we propose some estimators for the extreme value distribution based on the interval method and mid-point approximation method from the progressive Type-I interval censored sample. Because log-likelihood function is a non-linear function, we use a Taylor series expansion to derive approximate likelihood equations. We compare the proposed estimators in terms of the mean squared error by using the Monte Carlo simulation.

• 한국유체기계학회 논문집
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• 제17권3호
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• pp.5-12
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• 2014

This paper presents a design optimization for meridional profile and blade angle ${\theta}$ of a centrifugal compressor with DOE (design of experiments) and RSM (response surface method). Control points of the $3^{rd}$ order Bezier curve are used for design parameters and specific overall efficiency is used as object function. The response surface function shows good agreement with the 3D computational results. Three different optimized designs are proposed and compared with reference design at design point and off-design point. Contours of relative Mach number, static entropy, and total pressure are analyzed for improvement of performance by optimization. Off-design performance analysis is conducted by total pressure and efficiency.

• 한국의류학회지
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• 제34권12호
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• pp.2051-2061
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• 2010

Extreme sports refers to sports activities with a high level of inherent danger, such as extreme skiing, snow-boarding, mountain biking, motocross bicycling, aggressive in-line skating, wake-boarding, and paragliding. This study investigates the characteristics of extreme sports participants as group identities through an examination of the differences between extreme sports participants and traditional sports groups in lifestyle and sportswear benefits sought. We composed a total 108-item lifestyle profiles characterized by six lifestyle dimensions (dress, diet, home, recreation, consumption, and sense of values); in addition, we developed 32 items for sportswear benefits sought. The surveys targeted 422 sports participants living in Korea (216 men and 206 women, aged 15-23): 119 extreme sports participants and 303 traditional sports participants. All items were evaluated on a 5-point Likert scale, and SPSS 17.0. was used for data analysis. Exploratory factor analysis was conducted to confirm the substructure of each lifestyle dimension and sportswear benefits sought. The results of the factor analysis on each lifestyle dimension are as follows: 5 factors in dress dimension, 4 in diet, 3 in home, 6 in recreation, 5 in consumption, and 6 in sense of values. Six factors of sportswear benefit sought were identified. A t-test revealed that there were significant differences between the two groups in lifestyle dimensions and sportswear benefits sought. This study reveals that the lifestyle characteristics of extreme sports participants are more likely than traditional sports group to be more self-expressive, more distinctive, more fashion-oriented, more conspicuous, and more brand-oriented, while preferring more active sports, more dynamic leisure, and a more sensible life. Another finding is that extreme sports participants seek the distinctive, conspicuous, and latest sportswear benefits.

• 대한수학회논문집
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• 제10권4호
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• pp.875-880
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• 1995

Let $S_p(\alpha)$ denote the class of the Spirallike functions of order $\alpha, 0 < $\mid$\alpha$\mid$ < \frac{\pi}{2}$ Let $\Pi_N$ denote the subset of $S_p(\alpha)$ consisting of all products $z\Pi^N_{j=1}(1-u_j z)^{-mt_j}$ where $m = 1 + e^{-2i\alpha},$\mid$u_j$\mid$ = 1, t_j > 0$ for $j = 1, \cdots, N$ and $\sum^{N}_{j=1}{t_j = 1}$. In this paper we prove that extreme points of $S_p(\alpha)$ may be found which lie in $\Pi_N$ for some $N \geq 2$. We are let to conjecture that all exreme points of $S_p(\alpha)$ lie in $\Pi_N$ for somer $N \geq 1$ and that every such function is an extreme point.

• Kyungpook Mathematical Journal
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• 제60권3호
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• pp.485-505
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• 2020

We present a complete description of all the extreme points of the unit ball of 𝓛_s(²𝑙³_∞) which leads to a complete formula for ║f║ for every f ∈ 𝓛_s(²𝑙³_∞)^∗. We also show that $extB_{{\mathcal{L}}_s(^2l^3_{\infty})}{\subset}extB_{{\mathcal{L}}_s(^2l^n_{\infty})}$ for every n ≥ 4. Using the formula for ║f║ for every f ∈ 𝓛_s(²𝑙³_∞)^∗, we show that every extreme point of the unit ball of 𝓛_s(²𝑙³_∞) is exposed. We also characterize all the smooth points of the unit ball of 𝓛_s(²𝑙³_∞).

• Ocean Science Journal
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• 제41권4호
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• pp.245-254
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• 2006

Long term wave climate of both extreme wave and operational wave height is essential for planning and designing coastal structures. Since the field wave data for the waters around Korean peninsula is not enough to provide reliable wave statistics, the wave climate information has been generated by means of long-term wave hindcasting using available meteorological data. Basic data base of hindcasted wave parameters such as significant wave height, peak period and direction has been established continuously for the period of 25 years starting from 1979 and for major 106 typhoons for the past 53 years since 1951 for each grid point of the North East Asia Regional Seas with grid size of 18 km. Wind field reanalyzed by European Center for Midrange Weather Forecasts (ECMWF) was used for the simulation of waves for the extra-tropical storms, while wind field calculated by typhoon wind model with typhoon parameters carefully analyzed using most of the available data was used for the simulation of typhoon waves. Design wave heights for the return period of 10, 20, 30, 50 and 100 years for 16 directions at each grid point have been estimated by means of extreme wave analysis using the wave simulation data. As in conventional methodsi of design criteria estimation, it is assumed that the climate is stationary and the statistics and extreme analysis using the long-term hindcasting data are used in the statistical prediction for the future. The method of extreme statistical analysis in handling the extreme vents like typhoon Maemi in 2003 was evaluated for more stable results of design wave height estimation for the return periods of 30-50 years for the cost effective construction of coastal structures.