• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제4권1호
• /
• pp.7-18
• /
• 1997

Consider an $r\;\times\;c$ contingency table under the full multinomial model in which each classification is ordered. The problem is to test the null hypothesis of independence. A number of tests have been proposed for this problem. In this article we show that all of these tests can be improved on in some sense for most cases. In fact the preceding tests sometimes are inadmissible in a strict sense. Furthermore, we show by example that in some cases improved tests can yield substantially improved power functions.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
• /
• pp.75-76
• /
• 2015

Lifted flame stabilization mechanism can be explained with constant Schmidt number from the equation of $H^{\ast}_L/d^2_o=const{\times}v_e^{(2Sc-1)/(Sc-1)}$. In this research, a method of local Schmidt number was applied in order to measure edge flame propagation velocities, and edge flame propagation velocity was calculated from the trend between lift-off height and nozzle flow rate.

• 설비공학논문집
• /
• 제3권3호
• /
• pp.186-196
• /
• 1991

Numerical analysis has been performed to investigate the effects of the turbulence intensity and Prandtl number on the local heat transfer around a circular cylinder in crossflow. The governing equations were reformulated in a non-orthogonal coordinate system with Cartesian velocity components and discretised by the finite volume method with a non-staggered variable arrangement. For laminar flow, the calculations were performed for the Reynolds numbers 26 and 200. The results showed good agreement with the experimental results. For turbulent flow of the Reynolds number $1{\times}10^5$ and $2{\times}10^6$, the results showed that with an increase in the turbulent intensity in the main stream, the local Nusselt number increases in the front region of the circular cylinder. But the effect of turbulent intensity on the local Nusselt number diminishes in the wake region. The influence of Prandtl numbers show similar trend to that of turbulent intensity.

• 패션비즈니스
• /
• 제5권3호
• /
• pp.129-143
• /
• 2001

The purpose of this study is to pigeonhole theoretical notions of asymmetry and historical flow of asymmetry designed dresses, understand the trend of asymmetry design in modern fashion and find out its plastic character. The result of this study is as follows. The asymmetry is un-harmony artistic structure that unbalanced left and right in designing. The asymmetry fashion were seen that drapery dress of Egypt, Greece, Rome in ancient times and design by strong color contrast in heraldry and hose, accessory in the middle ages. In modern times, it was seen as complicated and mixed appearance by the influence of post-modernism. The asymmetry designs in modern fashion are shown varied styles by asymmetry of silhouette, detail, fabric, wearing method. The characters of these are a sense of de-construction, formative sense, and exaggeration The asymmetry design must be made by cutting, sewing, and high degree of technique through the latest skill and study.

• Environmental Analysis Health and Toxicology
• /
• 제27권
• /
• pp.2.1-2.4
• /
• 2012

Objectives: This study is a cross-sectional study to investigate the frequency of humidifier and humidifier disinfectant usage in the general population. Methods: A questionnaire was applied to 94 subjects (46 male, 48 female) from the general population of Gyeonggi Province. The questionnaire consisted of 3 scales (general characteristics, 5 items about humidifier usage, 5 items about humidifier disinfectant usage). Results: Thirty-five (37.2%) of the 94 subjects use a humidifier and humidifier disinfectant usage was found to be 18.1%. The frequency of humidifier usage is 4.8 times per a week and the humidifier disinfectant usage is 2.4 times per a week. Humidifier usage rate was highest in January. and then tended to rise gradually from October. Conclusions: Although this study population was not representative, we can say that approximately 50 percent of the humidifier users use a humidifier disinfectant and the trend of using a humidifier has shown seasonality.

• 한국대기환경학회지
• /
• 제16권4호
• /
• pp.389-398
• /
• 2000

Photocatalytic removal of benzene from air was examined using titanium dioxide photocatalyst films prepared on soda lime glass(50$\times$50$\times$2 mm) by spin coating and chemical vapor deposition. For the measurement of photocatalytic reactivity titanium dioxide coated glass was placed into a batch reactor and concentration of benzene in the reactor was set to abuot 100 ppm, and then illuminated with UV. It was found that catalytic reactivity of titanium dioxide films increased with the increase of titanium dioxide film thickness and then level off beyond a certain film thickness. UV absorption by the films showed the similar trend. The formation of stoichiometric amount of carbon dioxide was confirmed by measurement of carbon dioxide concentration in the reactor. In general spin coated films revealed better photocatalytic reactivity than chemically deposited one within the experimental ranges covered in this study. Morphology and crystal structure of prepared films were investigated by XRD and SEM and they showed significant difference between spin coated films and CVD films. Highest quantum efficiency of prepared titanium dioxide photocatalyst was close to 50%.

• Wind and Structures
• /
• 제15권6호
• /
• pp.463-480
• /
• 2012

The effects of Reynolds number (Re), freestream turbulence intensity (Tu) and integral length scale (${\Lambda}$) on the drag coefficient ($C_d$) of a circular cylinder in cross flow were experimentally studied for $6.45{\times}10^3$ < Re < $1.82{\times}10^4$. With the help of orificed plates, Tu was fixed at approximately 0.5%, 5%, 7% and 9% and the normalized integral length scale (L/D) was varied from 0.35 to 1.05. Our turbulent results confirmed the general trend of decreasing $C_d$ with increasing Tu. The effectiveness of Tu in reducing $C_d$ is found to lessen with increasing ${\Lambda}$/D. Most interestingly, freestream turbulence of low Tu (${\approx}5%$) and large ${\Lambda}$/D (${\approx}1.05$) can increase the $C_d$ above the corresponding smooth flow value.

• 물과 미래
• /
• 제22권3호
• /
• pp.331-339
• /
• 1989

추계학적 모형 중의 하나인 Multiplicative ARIMA 모형을 사용하여 주기성과 경향성을 가지는 월유량계열을 예측하였으며 그 모형의 적합성은 낙동강 유역의 진동 수위 관측 지점에서의 23년간의 월 유량자료를 사용하여 검정하였다. 최종적으로 산정된 ARIMA (2,0,0)$\times$$(0,1,1)_{12}$ 모형의 변수는 21년간의 자료를 사용하여 산정하였으며 나머지 2년간의 월 유량자료는 예측치와 관측치를 비교하는데 사용하였다. 본 모형에 의한 에측치와 관측치의 비교결과 Multiplicative ARIMA 모형은 진동지점의 월유량 계열의 예측에 적합함이 판명되었다.

• 수산해양교육연구
• /
• 제20권3호
• /
• pp.410-415
• /
• 2008

To evaluate the performance of nucleate boiling heat transfer between a plain and micro-fin surfaces, the experimental tests have been carried out under various conditions with fluorinert liquid FC-72, which is chemically and electrically stable. Two kinds of micro fins with the dimensions of $200{{\mu}m}{\times}20{{\mu}m}$ and $100{{\mu}m}{\times}10{{\mu}m}$ (width x height) were fabricated on the surface of a silicon chip. The experiments were performed on the liquid subcooling of 5, 10 and 20K under the atmospheric condition. The presented data showed a similar trend in the comparison with result of Rainey & You. Due to its expanded surface areas, the heat flux properties has been significantly enhanced on micro-fin surface comparing to the plain surface.

• Asian-Australasian Journal of Animal Sciences
• /
• 제7권4호
• /
• pp.499-503
• /
• 1994

One thousand and eighty eggs of Japanese quail (Coturnix coturnix Japonica) were set into the incubator maintaining 36 treatment groups (3 egg weight groups ${\times}3$ seasons ${\times}4$ preincubation holding periods) to evaluate their hatchability performances. Holding periods had significant (p<0.05) effect on hatchability and the seasons showed significant (p<0.05) effect on chick weight. All the parameters (except fertility) were significantly (p<0.01) influenced by the egg weight. None of the parameters maintained regular trend with egg weight and pre-incubation holding periods. Significant interactions were not observed on any of the parameters (except fertility) studied. The egg weight maintained significant (p<0.05) negative correlation with fertility and positive correlation with chick weight. Eggs of medium weight (9.10 to 10.00 cm) could be hatched satisfactorily between 4 and 7 days of pre-incubation holding periods in any season of the year.