• Communications for Statistical Applications and Methods
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• 제31권3호
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• pp.263-277
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• 2024

This paper proposes new parameterizations of the tilted beta binomial distribution, obtained from the combination of the binomial distribution and the tilted beta distribution, where the beta component of the mixture is parameterized as a function of their mean and variance. These new parameterized distributions include as particular cases the beta rectangular binomial and the beta binomial distributions. After that, we propose new linear regression models to deal with overdispersed binomial datasets. These new models are defined from the proposed new parameterization of the tilted beta binomial distribution, and assume regression structures for the mean and variance parameters. These new linear regression models are fitted by applying Bayesian methods and using the OpenBUGS software. The proposed regression models are fitted to a school absenteeism dataset and to the seeds germination rate according to the type seed and root.

• 설비공학논문집
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• 제13권3호
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• pp.145-152
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• 2001

Low Rayleigh number thermal convection in a fluid layer confined between two-infinite horizontal walls kept at spatially sinusoidal temperature distributions, T_L=T_m+\Delta T\sin \kappax,\;T_U=T_m+\Delta T\sin(\kappax-\beta)$, is theoretically investigated by a regular perturbation expansion method. For small wave numbers, an upright cell is formed between the two walls at $\beta$=0. The cell is tilted, as the phase difference increases, and a flow with tow counter-rotating eddies occurs at $\beta=\pi$. when the wave number is large, isolated eddies are formed near the lower and upper walls, for all the phase differences. There exists a wave number at which maximum heat transfer rate at the walls occurs, at each of the phase differences. And the wave number increases with increase of the phase difference. for a fixed wave number, the heat transfer rate decrease with increase of the phase difference.

• Ocean Science Journal
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• 제41권4호
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• pp.301-313
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• 2006

Abundance and distribution of phytoplankton in seawater at southwestern East/Japan Sea near Gampo were investigated by HPLC analysis of photosynthetic pigments during summer of 1999. Detected photosynthetic pigments were chlorophyll a, b, $c_{1+2}$ (Chl a, Chl b, Chl $c_{1+2}$), fucoxanthin (Fuco), prasinoxanthin (Pras), zeaxanthin (Zea), 19'-butanoyloxyfucoxanthin (But-fuco) and beta-carotene (B-Car). Major carotenoid was fucoxanthin (bacillariophyte) and minor carotenoids were Pras (prasinophyte), Zea (cyanophyte) and But-fuco (chrysophyte). Chl a concentrations were in the range of $0.16-8.3\;{\mu}g/land$ subsurface chlorophyll maxima were observed at 0-10m at inshore and 30-50 m at offshore. Thermocline and nutricline tilted to the offshore direction showed a mild upwelling condition. Results from size-fraction showed that contribution from nano+picoplankton at Chl a maximum layer was increased from 18% at inshore to 69% at offshore on average. The maximum contribution from nano+picoplankton was found as 87% at St. E4. It was noteworthy that contribution from nano+picoplanktonic crysophytes and green algae to total biomass of phytoplankton was significant at offshore. Satellite images of sea surface temperature indicated that an extensive area of the East/Japan Sea showed lower temperature ($<18\;^{\circ}C$) but the enhanced Chi a patch was confined to a narrow coastal region in summer, 1999. Exceptionally high flux of low saline water from the Korea/Tsushima Strait seemed to make upwelling weak in summer of 1999 in the study area. Results of comparisons among Chi a from SeaWiFS, HPLC and fluorometric analysis showed that presence of Chi b cause underestimation of Chi a about 30% by fluorometric analysis but overestimation by satellite data about 30-75% compared to HPLC data.

• Applied Microscopy
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• 제34권1호
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• pp.71-81
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• 2004

본 연구에서는 등황란인 U. unicinctus 수정란의 난할과정과 형식에 대하여 관찰된 바를 보고하였다. U unicinctus성숙란을 인공수정했을 때 난할은 핵 개방(germinal vesicle breakdown)과 제1, 2감수분열 후에 수행되었으며, 유생기 까지 난할은 등할(equal cleavage), 전할(holoblastic cleavage)이었고 난할형식은 나선형 난할(spiral cleavage)인 것으로 관찰되었다. 최초 3회의 난할이 경할$\rightarrow$경할$\rightarrow$수평할이었고, 이후 경할-수평할이 반복되는 것으로 보였다. 4세포기에 할구의 배열에서 일부 할구들이 동물극으로 융기한 것과 8세포기에서 식물극 할구 배열이 동물극 할구 배열에 대하여 사선 배열한 것 등은 나선형 난할에서만 볼 수 있는 특징이었으나 제 3차 난할인 수평할에서 등할, 전할인 것이 관찰되므로서 나선형 난할을 수행하는 Spiralian의 전형에 속하지는 않는 것으로 보였다. 4세포기 이후의 할구 배열이 사선배열, 즉 나선형인 근거를 항-$\alpha$-,-$\beta$-튜블린 처리에 의해 관찰된 유사분열 기구의 행위로서 볼 수 있었다. 4$\rightarrow$8세포기의 유사분열 기구는 동물극-식물극 축에 수직으로 발생하고 사선방향으로 선회한 후 난할하므로서 결과에서 수평할 및 할구의 사선배열이 가능한 것을 볼 수 있었다.