• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.363-374
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• 2012

This paper studies the problem of tracking a re-entry vehicle (RV) in order to predict its impact point on the ground. Re-entry target dynamics combined with super-high speed has a complex non-linearity due to ballistic coefficient variations. However, it is difficult to construct a database for the ballistic coefficient of a unknown vehicle for a wide range of variations, thus the reliability of target tracking performance cannot be guaranteed if accurate ballistic coefficient estimation is not achieved. Various techniques for ballistic coefficient estimation have been previously proposed, but limitations exist for the estimation of non-linear parts accurately without obtaining prior information. In this paper we propose the ballistic coefficient ${\beta}$ model-based interacting multiple model-extended Kalman filter (${\beta}$-IMM-EKF) for precise tracking of an RV. To evaluate the performance, other ballistic coefficient model based filters, which are gamma augmented filter, gamma bootstrapped filter were compared and assessed with the proposed ${\beta}$-IMM-EKF for precise tracking of an RV.

• 한국식품영양과학회지
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• 제20권5호
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• pp.494-502
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• 1991

Diazotized chitin(CHITN) as supports of immobilized enzyme, which was obtained by alkaline hydrolysed chitin with NaN3 and HCI was employed to produce CHITN-Gase with glutaraldehyde as bifunctional reagent. Activities of CHITN-Gase were determined with reaction of p-nitro-pheol-$\beta$-D-glucopyranoside(PNG) in plug flow reactor as a reference of CHITA-Gase. Their optimum temperature, pH, Km and Vmax, mass transfer coefficient (h), effctiveness factor(η)were plotted with variation of flow rate and H/D. Mass transfer coefficient(h) of those enzymes increased because of their flux, as flow rates were increased and controlled by reaction rate. Effectiveness factor(η) of both enzymes were nearly 1.0.

• 전기학회논문지
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• 제58권4호
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• pp.770-776
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• 2009

The composites were fabricated by adding 0, 15, 30, 45[vol.%] $ZrB_2$ powders as a second phase to SiC matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by spark plasma sintering(SPS) were investigated. Reactions between ${\beta}$-SiC and $ZrB_2$ were not observed in the XRD and the phase analysis of the electroconductive SiC ceramic composites. The relative density of mono ${\beta}$-SiC, ${\beta}$-SiC+15[vol.%]$ZrB_2$, ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]$ZrB_2$ composites are respectively 99.24[%], 87.53[%], 96.41[%] and 98.11[%] Phase analysis of the electroconductive SiC ceramic composites by XRD revealed mostly of ${\beta}$-SiC, $ZrB_2$ and weakly of $ZrO_2$ phase. The flexural strength showed the lowest of 114.44[MPa] for ${\beta}$-SiC+15[vol.%]$ZrB_2$ powders and showed the highest of 210.75[MPa] for composite no added with $ZrB_2$ powders at room temperature. The trend of the mechanical properties of the electroconductive SiC ceramic composites is accorded with the trend of the relative density. The electrical resistivity of the electroconductive SiC ceramic composites decreased with increased $ZrB_2$ contents. The electrical resistivity of mono ${\beta}$-SiC, ${\beta}$-SiC+15[vol.%]$ZrB_2$, ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]$ZrB_2$ composites are respectively $4.57{\times}10^{-1},\;2.13{\times}10^{-1},\;2.68{\times}10^{-2}\;and\;1.99{\times}10^{-2}[{\Omega}{\cdot}cm]$ at room temperature. The electrical resistivity of mono ${\beta}$-SiC and ${\beta}$-SiC+15[vol.%]$ZrB_2$ are negative temperature coefficient resistance(NTCR) in temperature ranges from $25[^{\circ}C]\;to\; 100[^{\circ}C]$. The electrical resistivity of ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]ZrB_2$ are positive temperature coefficient resistance(PTCR) in temperature ranges from $25[^{\circ}C]\;to\;100[^{\circ}C]$. It is convinced that ${\beta}$-SiC+30[vol.%]$ZrB_2$ composites by SPS for heater or ignitors can be applied.

• Kyungpook Mathematical Journal
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• 제46권3호
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• pp.425-431
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• 2006

In this paper, by introducing three parameters A, B and ${\lambda}$, and estimating the weight coefficient, we give a new extension of Hardy-Hilbert's inequality with a best constant factor, involving the Beta function. As applications, we consider its equivalent inequality.

• Journal of the Korean Statistical Society
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• 제35권1호
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• pp.79-90
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• 2006

We consider the subdiagonal bilinear model and ARMA model with subdiagonal bilinear errors. Sufficient conditions for geometric ergodicity of associated Markov chains are derived by using results on generalized random coefficient autoregressive models and then strict stationarity and ,a-mixing property with exponential decay rates for given processes are obtained.

• 한국지반공학회논문집
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• 제26권11호
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• pp.99-110
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• 2010

연구에서는 부주면마찰력이 발생하는 3개 지역 총 16본 말뚝의 현장 계측 자료들을 바탕으로 국내 지반 특성에 맞는 주면마찰계수($\alpha$, $\beta$ 계수)의 분포범위를 압밀도(U)와 역청재(S.L) 도포 유무에 따라 역산정하였다. 역청재 도포 말뚝의 부주면마찰력 저감효과는 50~90% 정도인 것으로 나타났으며, 기존 설계에 사용되던 제안 값과의 비교를 통해, 본 연구에서 산정된 $\alpha$와 $\beta$계수가 적정 범위에 있으며, 그 결과 국내지반조건을 반영한 말뚝의 장, 단기 주면마찰력을 예측할 수 있는 기본자료를 제시하였다.

• 한국식품영양학회지
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• 제25권4호
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• pp.871-877
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• 2012

추출조건에 따른 귀리겨 ${\beta}$-glucan의 추출조건을 확립하기 위하여 추출온도($40{\sim}60^{\circ}C$), 추출용매의 에탄올 농도(0~20%) 및 pH(5~9)를 변수로 중심합성계획법으로 설계하여 ${\beta}$-glucan 추출특성을 조사하였다. 추출시간의 증가에 따라 ${\beta}$-glucan의 추출속도는 추출초기에 급격히 증가하였으나, 이후에는 완만하였다. 총괄물질전달계수는 $3.363{\sim}8.552{\times}10^{-6}cm/min$ 범위로 낮은 추출온도에서는 추출용매의 농도가 낮을수록, 높은 추출온도에서는 추출용매의 농도가 높을수록 증가하였지만 pH에 의한 영향은 적은 것으로 나타났다. 추출용매의 pH는 중성일 때보다 산성이나 알칼리성일 때 ${\beta}$-glucan의 추출량이 증가하였다. 추출조건에 따라서 ${\beta}$-glucan 수용액의 점도는 유의적인 차이를 보였으며, 총괄물질전달계수가 높을수록 crude ${\beta}$-glucan 수용액의 점도가 높게 나타났으며, 점도, 추출율 및 총괄물질전달계수의 상관관계를 분석한 결과, 각각의 요인들이 높은 양의 상관관계(p<0.01)를 나타내었다.

• 약학회지
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• 제37권4호
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• pp.331-340
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• 1993

Inclusion complex of omeprazole(OMZ) with hydroxypropyl-$\beta$-cyclodextrin(HP-$\beta$-CD) was prepared by freeze-drying method. The complexation was confirmed by means of UV, CD, IR, DSC, XRD and $^{1}$H-NMR spectra. The benzimidazole moiety of OMZ might be found to be included into the cavity of HP-$\beta$-CD and the inclusion complex appeared to be $A_{L}$ type. The stoichiometric ratio of OMZ : HP-$\beta$-CD was found to be 1:1, and the stability constants of the inclusion complex by solubility and UV method were about 34 and 45 M$^{-1}$, respectively. The dissolution of OMZ was significantly enhanced from powder and. yablet of OMZ-HP-$\beta$-CD complex when compared to those of OMZ alone, and oil-to-water partition coefficient of OMZ-HP-$\beta$-CD complex was significantly higher than that of OMZ alone. Therefore, it was expected that the bioavailability of OMZ could be improved markedly by inclusion complexation of OMZ with HP-$\beta$-CD.

• Communications for Statistical Applications and Methods
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• 제17권5호
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• pp.639-645
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• 2010

We consider a subdiagonal bilinear model and give sufficient conditions for the associated Markov chain defined by Pham (1985) to be uniformly ergodic and then obtain the $\beta$-mixing property for the given process. To derive the desired properties, we employ the results of generalized random coefficient autoregressive models generated by a matrix-valued polynomial function and vector-valued polynomial function.

• Journal of the Korean Statistical Society
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• 제8권2호
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• pp.107-109
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• 1979

Consider a linear model with n observations and k explanatory variables: (1)b $y=X\beta+u, u\simN(0,\sigma^2I_n)$. We assume that the model satisfies the ideal conditions. Consider the general linear constraints on regression coefficient vector: (2) $R\beta=r$, where R and r are known matrices of orders $q\timesk$ and q\times1$ respectively, and the rank of R is $qk+q$.