• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년 추계학술대회논문집
• /
• pp.316-320
• /
• 2008

In this paper, the near wake of stationary and transversely oscillating square section cylinders with different corner radii are studied by numerical method to investigate the influence of corner radius. Six models R/D=0,0.1,0.2,0.3,0.4,0.5 (R is the corner radius and D is the characteristic dimension of the body) were studied. It was found that the corner radius of square cylinder significantly influences the flow features around the body both in stationary and oscillating conditions. Results indicate that, as R/D ratio increases, the Strouhal number increases and the separation point decrease for the stationary and oscillating cases.

• 대한수학회보
• /
• 제46권5호
• /
• pp.835-844
• /
• 2009

The ridgelet transform is extended to the space of square integrable Boehmians. It is proved that the extended ridgelet transform $\mathfrak{R}$ is consistent with the classical ridgelet transform R, linear, one-to-one, onto and both $\mathfrak{R}$, $\mathfrak{R}^{-1}$.1 are continuous with respect to $\delta$-convergence as well as $\Delta$-convergence.

• 대한수학회지
• /
• 제34권3호
• /
• pp.707-717
• /
• 1997

The square of Brownian density process $Q^\lambda$ is defined where $\lambda$ is a parameter. Applying limit theorems of stochastic integrals w.r.t. martingale measure, we prove a weak limit theorem for $Q^\lambda$ in $D_{S'(R^d)}[0,1]$.

• 대한수학회지
• /
• 제59권3호
• /
• pp.439-448
• /
• 2022

For a natural number n, let R(n) denote the number of representations of n as the sum of one square and five cubes of primes. In this paper, it is proved that the anticipated asymptotic formula for R(n) fails for at most $O(N^{{\frac{4}{9}+{\varepsilon}})$ positive integers not exceeding N.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집
• /
• pp.486-489
• /
• 2002

Temperature(T) dependence of the sheet resistance( $R_{$\square$}$) has been investigated on the c-axis oriented thin films of the (Bi2212/Bi2201) mixed crystal with different molar fractions. The $R_{$\square$}$-T superconducting characteristic deteriorated with reduction of the Bi2212 fraction, and almost disappears at 48 mol% where a superconductor-to-insulator transition took place, with the resistance on the normal state, RN, reaching 4.l㏀ at 80 K. This $R_{N}$ value is close to the universal quantum number, h/(2e)$^2$≡6.5㏀ predicted by the Kosterlitz-Thouless(KT) transition theory. The $R_{$\square$}$-T characteristics of the 48 mol% thin film can be elucidated as a competitive process of KT transition brought about by charge or vortex in the two-dimensional layer structure.e.

• 대한간호학회지
• /
• 제43권3호
• /
• pp.321-330
• /
• 2013

Purpose: This cross-sectional study was done to compare factors influencing young adolescents' aggression according to family structure. Methods: Participants were 680 young adolescents aged 11 to 15 years (113 in single father families, 136 in single mother families, 49 in grandparent families, and 382 in both-parent families). All measures were self-administered. Data were analyzed using SPSS 18.0 program and factors affecting young adolescents' aggression were analyzed by stepwise multiple regression. Results: Levels of young adolescents' aggression and all variables were significantly different among the four family structure groups. Factors influencing young adolescents' aggression were also different according to these 4 groups. For single father families, depression-anxiety and family hardiness significantly predicted the level of young adolescents' aggression (adjusted R square=.37, p<.001). For single mother families, depression-anxiety, gender, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For grandparent families, depression-anxiety and family support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For both-parent families, depression-anxiety, family hardiness, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.48, p<.001). Conclusion: Nurses working with young adolescents should consider family structure-specific factors influencing aggression in this population.

• 대한물리의학회지
• /
• 제10권1호
• /
• pp.37-43
• /
• 2015

PURPOSE: The purpose of this study is to investigate the effect of the physical therapy treatment room environment using microwave diathermy on the autonomic nervous system of human body. METHODS: Participants were 24 healthy adults. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences(RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were compared in microwave irradiation and non-irradiation group. Data were analyzed in Wilcoxon's signed-ranks test and Mann-Whitney U test. RESULTS: Standard deviation of all normal R-R intervals (SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different in microwave irradiation group. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different in microwave non-irradiation group. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different between two groups. CONCLUSION: There was no significant change in the sympathetic nervous system and parasympathetic nervous system regardless of the presence of microwave irradiation. There was no significant change in the autonomic nervous system adaptability regardless of the presence of microwave irradiation.According to this study, microwave diathermy does not have significant effect on the autonomic nervous system.Future study is necessary to investigate the long term effect of the physical therapy treatment room environment using microwave diathermy on the autonomic nervous system of the human body.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2007년도 추계 학술대회논문집
• /
• pp.115-119
• /
• 2007

In this paper, a flow visualization analysis has been carried out on an oscillating square section cylinder, numerically, using a commercially available code CFD-ACE. In this study, the square cylinder is forced to oscillate at different frequencies of excitation, viz., fe/fo=0.5, 1.0 and 2.0 (where, fe is the excitation frequency provided to the cylinder and fo is the natural vortex shedding frequency from the stationary cylinder at a particular Reynolds number (=5200). In all the cases, the peak-to-peak amplitude of oscillation is kept at 32% of the side dimension of the square cylinder. These studies are conducted to understand the influence of frequency of oscillation on the flow field features around the cylinder, particularly the mode of vortex shedding. Results indicate that, the flow field around a square cylinder is very much influenced by the excitation frequency, in particular the vortex shedding mode. It is also found that, the vortex street parameters are significantly influence by the oscillation frequency. Comparison with earlier reported experimental studies has also been attempted in this paper. In appears that, such a numerical exercise (as performed in this paper) is first of its kind. It is believed that, these studies would enable one to understand the mechanisms underlying the flow-induced vibrations of a square section cylinder.

• 한국정보통신학회논문지
• /
• 제9권1호
• /
• pp.188-198
• /
• 2005

부동소수점 제곱근 계산에 많이 사용하는 골드스미트 제곱근 알고리즘은 곱셈을 반복하여 제곱근을 계산한다. 본 논문에서는 골드스미트 제곱근 알고리즘의 반복 과정의 오차를 예측하여 오차가 정해진 값보다 작아지는 시점까지 반복 연산하는 알고리즘을 제안한다. 'F'의 제곱근 계산은 초기값 $X_0=Y_0=T^2{\times}F,\;T=\frac{1}{\sqrt {F}}+e_t$에 대하여, $R_i=\frac{3-e_r-X_i}{2},\;X_{i+1}=X_i{\times}R^2_i,\;Y_{i+1}=Y_i{\times}R_i,\;i{\in}\{{0,1,2,{\ldots},n-1} }}'$을 반복한다 곱셈 결과는 소수점 이하 p 비트 미만을 절삭하며, 절삭 오차는 $e_r=2^{-p}$보다 작다. p는 단정도실수에서 28, 배정도실수에서 58이다. $X_i=1{\pm}e_i$ 이면 $X_{i+1}$ = $1-e_{i+1}$ $e_{i+1} {\frac{3e^2_i}{4}{\mp}\frac{e^3_i}} $ +4$e_{r}$이다. $|X_i-1|$ < $2^{\frac{-p+2}{2}}$이면, $e_{i+1}$ < $8e_{r}$ 이 부동소수점으로 표현할 수 있는 최소값보다 작게 되며, $\sqrt{F}$ {\fallingdotseq}\frac{Y_{i+1}}{T}}$이다. 본 논문에서 제안한 알고리즘은 입력 값에 따라서 곱셈 횟수가 다르므로, 평균 곱셈 횟수를 계산하는 방식을 도출하고, 여러 크기의 근사 역수 제곱근 테이블 ($T=\frac{1}{\sqrt{F}}+e_i$)에서 단정도실수 및 배정도실수의 제곱근 계산에 필요한 평균 곱셈 횟수를 계산한다. 이들 평균 곱셈 횟수를 종래 알고리즘과 비교하여 본 논문에서 제안한 알고리즘의 우수성을 증명한다. 본 논문에서 제안한 알고리즘은 오차가 일정한 값보다 작아질 때까지만 반복하므로 제곱근 계산기의 성능을 높일 수 있다. 또한 최적의 근사 역수 제곱근 테이블을 구성할 수 있다. 본 논문의 연구 결과는 디지털 신호처리, 컴퓨터 그래픽스, 멀티미디어, 과학 기술 연산 등 부동소수점 계산기가 사용되는 분야에서 폭 넓게 사용될 수 있다.

• 디지털융복합연구
• /
• 제13권12호
• /
• pp.117-124
• /
• 2015

빅데이터로 인해 통계분석에 대한 수용이 증대되면서 구조방정식모형과 같은 진보된 2세대 분석방법의 필요성이 증가하고 있다. 본 연구는 다양한 연구 분야에서 이용되는 구조방정식모형 중 부분최소제곱모형(PLS-SEM)을 적용하는데 있어 오픈 소프트웨어인 R의 활용방법에 대해서 제안하고자 한다. R은 GNU 프로젝트의 일부로서 무료이고, 빅데이터를 포함한 통계분석에 강력하면서도 유용한 도구이다. 이에 부분최소제곱모형의 대표적인 통계패키지인 SmartPLS와 본 연구가 제안하는 R을 활용하여 측정모형의 집중타당성, 판별타당성, 내적일관성을 분석하고, 구조 모형의 경로계수 및 조절효과를 분석하여 결과를 각각 비교 분석하였다. 분석결과 R은 측정모형과 구조모형에서 모두 SmartPLS와 동일한 결과를 나타내었고, 향후 상용 통계패키지를 대체할 수 있는 강력한 도구임을 확인하였다.