• 대한수학회논문집
• /
• 제28권2호
• /
• pp.371-381
• /
• 2013

In this paper, we investigate some properties of ${\theta}$-($\mathcal{G}$, $\mathcal{H}$)-continuous functions in a grill topological spaces. Moreover, the relationships with other related functions are investigated.

• KSBB Journal
• /
• 제25권5호
• /
• pp.471-477
• /
• 2010

In order to improve bio-ethanol productivity by various cultivation methods in this paper, the culture modes using food wastes, such as batch culture, high-cell-density fermentation, SSF (simultaneous saccharification and fermentation) by fill & draw, continuous culture by fill & draw were performed and their productivities were compared. SSFs by fill & draw were performed by continuous decompression using 1 L evaporator system, and by 10 L bioreactor without decompression. In addition, the continuous cultures by fill & draw mode using SFW (saccharafied food wastes) medium were performed by changes of 40% culture broth with intervals of 12 h (0.03 $h^{-1}$), 6 h (0.07 $h^{-1}$), 3 h (0.13 $h^{-1}$). Consequently, productivities of bio-ethanol were 2.52 g/L-h and 1.30 g/L-h in batch culture and high- cell-density fermentation, respectively. The productivities of SSF by fill & draw showed 2.24 g/L-h and 2.03 g/L-h in continuous decompression with 1 L evaporator and 10 L bioreactor without decompression, respectively. Also, the productivities in continuous culture by fill & draw modes showed 2.02 g/L-h, 4.07 g/L-h and 6.25 g/L-h by medium change with intervals of 12 h, 6 h, and 3 h, respectively. In conclusion, the highest ethanol productivity was obtained in the continuous culture mode by fill & draw with dilution rate of 0.13 $h^{-1}$.

• Transactions on Control, Automation and Systems Engineering
• /
• 제2권3호
• /
• pp.163-168
• /
• 2000

The problems of mixed $H_2/H_{\infty}$ filtering design fer continuous and discrete time linear systems with time delay are investigated. The main purpose is to design a stable mixed $H_2/H_{\infty}$ filter which minimizes the H$_2$Performance measure satisfying a prescribed H$_{\infty}$ norm bound on the closed loop system in continuous-time case and discrete-time case, respectively. The sufficient conditions of existence of filter, the mixed $H_2/H_{\infty}$ filter design method, and the upper bound of performance measure are proposed by LMI(linear matrix inequality) techniques in terms of all finding variables. Also, we present optimization problems in order to get the optimal mixed $H_2/H_{\infty}$ filter in continuous and discrete time case, respectively.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권1호
• /
• pp.1-5
• /
• 2001

The potential use of spin filter device to retain Propionibacterium acidipropionici in the bioreactor under continuous mode of fermentation, and improve acid productivity, was examined. The yield of propionic acid based on lactose concentration was 51% in batch and 54% in continuous (dilution rate = 0.05 h(sup)-1) operation. The yield in continuous fermentation with cell retention using spin filter of 10 micron size (dilution rate = 0.05 h(sup)-1) was even higher at 70% (w/w). The volumetric productivity under batch and continuous mode of operation were 0.312g L(sup)-1 h(sup)-1 and 0.718g L(sup)-1 h(sup)-1 respectively. Continuous fermentation with cell retention demonstrated even higher volumetric productivities at 0.98g L(sup)-1 h(sup)-1 with out clogging problems. It could be used for utilization of cheese whey to produce propionic acid at higher yield and productivities.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
• /
• pp.29-32
• /
• 2001

This paper presents matrix inequality conditions for H$_2$optimal control of linear time-invariant descriptor systems in continuous and discrete time cases, respectively. First, the necessary and sufficient condition for H$_2$control and H$_2$controller design method are expressed in terms of LMls(linear matrix inequalities) with no equality constraints in continuous time case. Next, the sufficient condition for H$_2$control and H$_2$controller design method are proposed by matrix inequality approach in discrete time case. A numerical example is given in each case.

• 대한수학회논문집
• /
• 제11권1호
• /
• pp.169-174
• /
• 1996

Let $C_\alpha$ be the collection of those members of $C[0,1]$ which are H$\ddot{o}lder $\alpha$-continuous functions on [0,1]. In this paper, I will show that $\mu(C_{\frac{1}{2}) = 0$ for Wiener measure $\mu$.

• 대한수학회보
• /
• 제38권3호
• /
• pp.517-526
• /
• 2001

In this paper, we study the continuous wavelet transform on the Heisenberg group H$^n$, and describe the related continuous multiscale analysis. By using the wavelet packet transform we obtain a reconstruction formula on L$^2$(H$^n$).

• Kyungpook Mathematical Journal
• /
• 제31권2호
• /
• pp.275-287
• /
• 1991

• 한국지능시스템학회논문지
• /
• 제12권6호
• /
• pp.565-570
• /
• 2002

We introduce the concepts of fuzzy H-continuity and fuzzy strongly closed graph, respectively and investigate some of their properties.

• 한국수소및신에너지학회논문집
• /
• 제24권2호
• /
• pp.99-106
• /
• 2013

The variations of performance and metabolites at an early stage were investigated for the successful start-up technology in continuous fermentative hydrogen production. Unsuccessful start-up was observed when the operation mode was changed from batch to continuous mode after the yield was reached to 0.5 mol $H_2$/mol $hexose_{added}$ by batch mode. $H_2$ production continued till 12 hours accompanied by butyrate production, but did not last with propionate production increase. It was suspected that the failure was due to the regrowth of propionic acid bacteria during batch mode which were inhibited by heat-shock but not completely killed. Thus, successful start-up was tried by early switchover from batch to continuous operation; continuous operation was started after the $H_2$ yield was reached to 0.2 mol $H_2$/mol $hexose_{added}$ by batch mode. Although $H_2$ production rate decreased at an early stage, stable $H_2$ yield of 0.8 mol $H_2$/mol $hexose_{added}$ was achieved after 10 days by lowering down propionate production. And it was also concluded that the reason for $H_2$ production decrease at an early stage was due to alcohol production by self detoxification mechanism against VFAs accumulation.