• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.149-154
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• 2017

To increase the efficiency of esterase production by Bacillus, high cell-density culture of recombinant Escherichia coli through fed batch fermentation was tested. Cells were cultured to $OD_{600}$ of 76 (35.8 g/l DCW) with dissolved oxygen level controlled to least above 30% air saturation by supplying pure oxygen. Cells were cultured to an $OD_{600}$ of 90 (42.4 g/l DCW) with glucose feeding controlled to at least 1 g/l. However, the cells reached stationary phase at the late stage of culture, despite glucose being supplied. Cells were cultured to an $OD_{600}$ of 185 (87.3 g/l DCW) by supplying additional medium with fortified yeast extract. To increase the productivity of the recombinant protein, cell growth and esterase productivity based on induction time were evaluated. Late exponential phase induction for esterase production in fed batch fermentation resulted in maximum optical density $OD_{600}$ of 190 (89 g/l DCW) and maximum esterase activity of 1745 U/l, corresponding to a 5.8-fold enhancement in esterase production, compared to the early exponential phase induction. In this study, we established fermentation methods for achieving maximum production of Bacillus-derived esterase by optimizing IPTG induction time in high-cell density culture by supplying pure oxygen and a nitrogen source.

• Communications for Statistical Applications and Methods
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• v.10 no.3
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• pp.795-804
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• 2003

In this article, a tomography for the estimation of the origin-destination(OD) traffic intensities in dynamic routing network is considered. Vardi(1996)'s approach based on fixed route is not directly applicable to dynamic routing protocols, which arises from the fact that we cannot access the route at every observation time. While it uses link-wise traffics as the observations, the proposed method considers the triple of ingress/outgress/relayed traffics data at each node so that we can transform the problem into a routing-independent tomography. An EM algorithm for implementation and some simulated experiments are provided.

• Journal of the Korean Mathematical Society
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• v.45 no.4
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• pp.1075-1087
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• 2008

We study a class of KMS-symmetric quantum Markovian semigroups on a quantum spin system ($\mathcal{A},{\tau},{\omega}$), where $\mathcal{A}$ is a quasi-local algebra, $\tau$ is a strongly continuous one parameter group of *-automorphisms of $\mathcal{A}$ and $\omega$ is a Gibbs state on $\mathcal{A}$. The semigroups can be considered as the extension of semi groups on the nontrivial abelian subalgebra. Let $\mathcal{H}$ be a Hilbert space corresponding to the GNS representation con structed from $\omega$. Using the general construction method of Dirichlet form developed in [8], we construct the symmetric Markovian semigroup $\{T_t\}{_t_\geq_0}$ on $\mathcal{H}$. The semigroup $\{T_t\}{_t_\geq_0}$ acts separately on two subspaces $\mathcal{H}_d$ and $\mathcal{H}_{od}$ of $\mathcal{H}$, where $\mathcal{H}_d$ is the diagonal subspace and $\mathcal{H}_{od}$ is the off-diagonal subspace, $\mathcal{H}=\mathcal{H}_d\;{\bigoplus}\;\mathcal{H}_{od}$. The restriction of the semigroup $\{T_t\}{_t_\geq_0}$ on $\mathcal{H}_d$ is Glauber dynamics, and for any ${\eta}{\in}\mathcal{H}_{od}$, $T_t{\eta}$, decays to zero exponentially fast as t approaches to the infinity.

• Journal of Korean Society of Rural Planning
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• v.23 no.2
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• pp.43-54
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• 2017

When an age of low growth and population decline, population migration plays an important role in spatial structure of region. There have been many researches on migration and regional spatial structure. The purpose of this study is to examine the changes of Gwangju and Jeonnam region's spatial structure and central area using social network analysis methods. For analysis it was used that population and migration data and passenger OD(Origin and Destination) travel data released by Statistics Korea and Korea Transport Database(KTDB). Using Gephi 0.8.2, migration and passenger OD networks were visualized, and this describe network flow and density. The results of the network centrality analysis show that the most populated village is not always network center though population mass is an important factor of central places. The average eigenvector centrality of 2010 migration is the lowest during 2005-2015, and it means few regions have high centralities. When comparing migration and travel networks, travel data is more effective than migration data in determining the central location considering spatial functions.

• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.189-200
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• 2015

In this study, we present the results of orbit determination (OD) using satellite laser ranging (SLR) data for the Science and Technology Satellite (STSAT)-2C by a short-arc analysis. For SLR data processing, the NASA/GSFC GEODYN II software with one year (2013/04 - 2014/04) of normal point observations is used. As there is only an extremely small quantity of SLR observations of STSAT-2C and they are sparsely distribution, the selection of the arc length and the estimation intervals for the atmospheric drag coefficients and the empirical acceleration parameters was made on an arc-to-arc basis. For orbit quality assessment, the post-fit residuals of each short-arc and orbit overlaps of arcs are investigated. The OD results show that the weighted root mean square post-fit residuals of short-arcs are less than 1 cm, and the average 1-day orbit overlaps are superior to 50/600/900 m for the radial/cross-track/along-track components. These results demonstrate that OD for STSAT-2C was successfully achieved with cm-level range precision. However its orbit quality did not reach the same level due to the availability of few and sparse measurement conditions. From a mission analysis viewpoint, obtaining the results of OD for STSAT-2C is significant for generating enhanced orbit predictions for more frequent tracking.

• KSBB Journal
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• v.26 no.2
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• pp.139-142
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• 2011

The chromatographic enantiomer separation of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters on four polysaccharide based chiral columns was performed. The 9-anthraldehyde Schiff base derivatives of ${\alpha}$- amino acid esters were readily synthesized by stirring the ${\alpha}$- amino acid ester hydrochloride salts with 9-anthraldehyde in the presence of 1,8-diazabicyclo [5.4.0]undec-7-ene as a base and anhydrous $MgSO_4$. Chiralcel OD or Chiralcel OD-H showed the greatest enantiomer resolution of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters. The L-enantiomers of all the analytes were preferentially retained on Chiralcel OD or Chiralcel OD-H. This analytical method was applied in the determination of optical purities of several commercially available D- or L-${\alpha}$-amino acid methyl esters.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.967-974
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• 2012

Cultivation of Spirulina platensis using ammonium salts or wastewater containing ammonium as alternative nitrogen sources is considered as a commercial way to reduce the production cost. In this research, by analyzing the relationship between biomass production and ammonium-N consumption in the fed-batch culture of Spirulina platensis using ammonium bicarbonate as a nitrogen nutrient source, an online adaptive control strategy based on optical density (OD) measurements for controlling ammonium feeding was presented. The ammonium concentration was successfully controlled between the cell growth inhibitory and limiting concentrations using this OD-based feedback feeding method. As a result, the maximum biomass concentration (2.98 g/l), productivity (0.237 g/l d), nitrogen-to-cell conversion factor (7.32 gX/gN), and contents of protein (64.1%) and chlorophyll (13.4mg/g) obtained by using the OD-based feedback feeding method were higher than those using the constant and variable feeding methods. The OD-based feedback feeding method could be recognized as an applicable way to control ammonium feeding and a benefit for Spirulina platensis cultivations.

• Journal of Auto-vehicle Safety Association
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• v.15 no.1
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• pp.35-44
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• 2023

The purpose of this study is to predict how the actual accident changes by reconstructing the accident with an Autonomous Emergency Braking system (AEB) based on the actual accident of the LTAP-OD (Left Turn Crossing Path - Opponent Direction) intersection. A virtual AEB sensor was developed, and 150 head-on collision accident reports were secured to the insurance company to reconstruct the accident. As a result of the accident type analysis, a total of 13 types of head-on collision accidents were derived, and it is the LTAP-OD intersection accident with the highest frequency. In the LTAP-OD intersection accident, the simulation was conducted by applying the virtual AEB of each vehicle, the accident rate decreased by 90% or more when the AEB of the left-turn vehicle was applied, and the accident rate decreased by 50%. In addition, the most frequent collision types in LTAP-OD accidents were the front bumper on the driver's side of a vehicle going straight and the front bumper on the passenger's side of a vehicle turning left.

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.573-576
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• 1999

The rate constants and kinetic solvent isotope effects (KSIE, KMeOH/kMeOD) for solvolyses of para-substituted phenylchloroformates in CH3OH, CH3OD, H2O, D2O, 50% D2O-CH3OD were determined at 15.0 and 25.0℃ using conductometric method. Kinetic solvent isotope effects for the solvolyses of para-substituted phenyl chloroformates were 2.39-2.51, 2.21-2.28, and 1.67-1.69 for methanol, 50% aqueous methanol, and water, respectively. The slopes of Hammett plot for solvolysis of para-substituted phenyl chloroformates in methanol, 50% aqueous methanol, and water were 1.49, 1.17 and 0.89, respectively. The Hammett type plot of KSIE, log (KSIE) versus p, can be a useful mechanistic tool for solvolytic reactions. The slopes of such straight lines for para-substituted phenyl chloroformates are almost zero in methanol, 50% aqueous methanol, and water. It was shown that the reaction proceeds via an associative SN2 and/or general base catalysis addition-elimination (SAN) mechanism based on activation parameters, Hammett p values, and slopes of Hammett type plot of KS-IE.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.159-168
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• 1999

Swine whipworm(Trichuris suis) is cosmopolitan nematode which can cause serious pathology in immature stage(larva2~larva5) of infected pigs, such as anorexia, diarrhea, anemia, and death in heavy infections. In this larval stages, it is very difficult to diagnose the infection of whipworm and to differentiate from other common swine gastrointestinal disorders such as 21 day scours which are associated with TGE virus, rota virus, coccidium, and the stress of weaning. In this experiment, the isolated antigens of Trichuris spp. were carried out to examine the structure and specificity of antigens and to select the reasonable antigens which would be used in serological diagnosis by electrophoresis, Western blotting, ELISA. The results of this experiment were as follows; 1. The common fractions of each Trichuris suis antigen were identified 28,32,45, 80kDa by SDS-PAGE with silver stain and four major fractions could be detected in positive swine sera by Western blot analysis. 2. The OD(optical density) values of somatic and excretory-secretory antigens which were reacted against positive(negative) sera from pigs infected with Trichuris suis by ELISA reader were; 1) OD values($mean{\pm}SD$) of adult somatic antigen against positive(negative) sera were $0.30{\pm}0.12(0.09{\pm}0.006)$ and third-stage larva of somatic antigen were $0.28{\pm}0.038(0.10{\pm}0.005)$. And OD values of excretory-secretory antigens of adult and third-stage larva were $0.24{\pm}0.031(0.11{\pm}0.005)$ and $0.08{\pm}0.013(0.10{\pm}0.003)$, respectively. 2) OD values of adult somatic, larval somatic antigen and adult excretory-secretory antigen response to positive sera were significantly (p<0.01) associated with negative swine sera. And the Cut-off OD values(minimum positive value) were determined to be mean negative value plus 3 SD that would minimized the risk of false positives. 3. The OD values of somatic antigens of T suis and T vulpis against swine positive(negative) sera were $0.30{\pm}0.120(0.09{\pm}0.006)$ and $0.25{\pm}0.141(0.09{\pm}0.003)$. These data mean that the somatic antigens of T suis and T vulpis were able to diagnose T vulpis infection in dogs as well as T suis infection in pigs. These results suggest that somatic antigen of third-stage larva and excretory-secretory antigen of adult T suis could be used the diagnostic antigen by serological test(ELISA) in immature Trichuris spp. infection.