• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.294-301
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• 2022

COVID-19 is a crisis with numerous casualties. The World Health Organization (WHO) has declared the use of masks as an essential safety measure during the COVID-19 pandemic. Therefore, whether or not to wear a mask is an important issue when entering and exiting public places and institutions. However, this makes face recognition a very difficult task because certain parts of the face are hidden. As a result, face identification and identity verification in the access system became difficult. In this paper, we propose a system that can detect masked face using transfer learning of Yolov5s and recognize the user using transfer learning of Facenet. Transfer learning preforms by changing the learning rate, epoch, and batch size, their results are evaluated, and the best model is selected as representative model. It has been confirmed that the proposed model is good at detecting masked face and masked face recognition.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.195-201
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• 2007

This study investigated the effects of various culture parameters (carbon sources, temperature, initial pH of culture, NaCl concentration, and light) on the growth and canthaxanthin production by Dietzia natronolimnaea HS-1. The results showed that the most effective carbon source for growth and canthaxantin production was glucose, and the best pH and temperature were 7 and $31^{\circ}C$, respectively. In addition, the biomass and canthaxanthin production increased in a medium without NaCl and in the presence of light. Under the optimized conditions, the maximum biomass, total carotenoid, and canthaxanthin production were $6.12{\pm}0.21g/l,\;4.51{\pm}0.20mg/l,\;and\;4.28{\pm}0.15mg/l$, respectively, in an Erlenmeyer flask system, yet increased to 7.25 g/l, 5.48 mg/l, and 5.29 mg/l, respectively, in a batch fermenter system.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.348-353
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• 1993

The optimal conditions for operating a moving-aeration bioreactor were determined as 30rpm and 150 (ml/min) of air flow rate, which can yield ca. 7.3 (l/h)of maximum mass transfer coefficient. It was also found that the agitation speed played much much important role than air input rate in oxgen transfer into the medium. $2.6{\times}10^6$ (cells/ml) and 0.6 (ml/l) of maximum cell denisty and IL-2 production were observed in batch cultivation of IL-2 producing BHK cell line. 0.53 (mM/l/h) of oxygen uptake rate was also estimated. The performance of a moving-aeration bioreactor (specific growth rate and oxygen uptake rate, etc.) was superior to other culture systems, such as cell-life and static membrane aeration bioreactors. Ii must be useful to apply this reactor to many culture processes by improving structural limitations in scaling-up the system.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.4
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• pp.78-85
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• 1998

Strains degrading and decolorizing reactive dyes, Procion blue HEGN and Procion red HE7B were isolated from water system, are named as RBK1 and RRK, the growth characteristics of which were investigated. Decolorization efficiencies after 42 hrs in batch culture were 95% and 77%, respectively. and the optimal culture condition of temperature and pH were $30^{\circ}C$, 7.0. Decolorization efficiencies in condition of aerobic shaking culture by strains RBK1 and RRK conspicuously increased, and culture by strain RBK1 was found as 95% after 42 hrs, while standing culture was 64%, Optimum nitrogen source was peptone, and It was found that decolorization efficiencies by strains RBK1 and RRK increased up to 4,000mg/l of peptone concentration as nitrogen source, but peptone concentration did' nt influence the decolorization efficiency in above 4,000mg/l. When the concentration of dyes were more than 800 mg/l and 400 mg/l respectively, the strains RBK1 and RRK, which degrade Procion bule HEGN and Procion red HE7B, showed a sharply decreased decolorization efficiencies; then the specific growth rate were $0.25hr^{-1}$ and $0.09hr^{-1}$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.4
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• pp.275-287
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• 2000

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, app58lication of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.

• Clean Technology
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• v.4 no.1
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• pp.45-59
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• 1998

Continuous immobilized-cell culture was carried out for the production of kasugamycin, a secondary metabolite by a filamentous bacteria, Streptomyces kasugaensis, with an intention of reducing waste generation. A sporulation medium was developed for production of bulk amounts of spores, and the spores were entrapped into celite biosupports for immobilization. It was possible to effectively keep the immobilized-cells inside the reactor during the continuous culture by an efficient immobilized cell separator of decantor type on the outlet of the fermentor. Using this continuous immobilized-cell fermentor system, we investigated the effects of feed substrate and phosphate concentrations on kasugamycin production and chemical oxygen demand(COD). Comparing with the conventional suspended-cell batch culture, the kasugamycin productivity was observed to increase by 2.5 times, whereas COD per unit kasugamycin production decreased by 2.3 times in the continuous immobilized-cell culture. Based on these results, the continuous immobilized-cell system was considered to be a cleaner bioprocess than the conventional batch suspended-cell system.

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.306-310
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• 2008

Characteristics of microalgal growth was investigated using anaerobic effluent from two-phase animal waste digestor as substrate. Batch experiments were carried out to investigate the effect of the initial nitrogen and phosphorus concentrations on growth of Microcystis aeruginosa, Chlorella sp. and Euglena gracilis. In 400 times diluted anaerobic effluent (TN 3 mg/L), single cell growth of the Euglena gracilis population increased twice without delay, although Chlorella sp. and Microcystis aerugenos take over 144 hours. Similar appearance with single cell growth was observed in mixed cultures. However, microalgae population did not increase under condition of 10 times diluted influent (TP 3 mg/L) in both pure and mixed cultures, which was affected by high organic and nitrogen concentration. Logistic growth model successfully fitted to determine biokinetic parameters such as ${\lambda}$: lag time, ${\mu}m$: maximal specific growth rate, A: asymptote of growth.

• Ocean and Polar Research
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• v.25 no.3
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• pp.269-275
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• 2003

Effects of different operating factors including superficial air velocity (SAV), hydraulic residence time (HRT), protein concentration, and foam overflow height on protein removal by a foam fractionator in simulated seawater aquaculture system were investigated. This experiment was conducted on batch and consecutive modes at different combinations of the affecting factors. The foam fractionator had a diameter of 20cm and a height of 120cm and the experiment was conducted with synthetic wastewater. In 5 consecutive trials, protein concentrations in culture tank water decreased faster when the foam fractionator was operated at higher SAVs and lower HRTs. In batch trials, protein removal rates increased with an increase in SAV but decreased with an increase in URT. Higher protein concentrations in the bulk solution resulted in higher protein removal rates. Protein concentrations in the collected foam condensates increased but the foam overflow rates decreased with the increase of foam overflow heights. The results of this experiment indicate that foam fractionation would be an effective way for protein removal in seawater aquaculture systems and the performance of the foam fractionator depends largely on the operating parameters, especially SAV.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.46-53
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• 1999

The purpose of this study was to optimize the conditions of continuous mixed culture of C.butyricum and R. spaeroides K-7, which were able to produce hydrogen using biomass-dreived substrate. To investigate the possibility of continuous culture, semi-continuous culture was carried out for 20 days. In semi-continuous culture using the reactor system, the replacement rate of fresh medium was 30% of total medium volume for the highest hydrogen evolution. In continuous culture, the optimum dilution rate was determined to be 0.05$h^{-1}$. The continuous culture produced 3.1 times as compared with the hydrogen on batch culture. On the other hand, the continuous mixed culture produced 1.3~2.1 times as much as hydrogen of the continuous monoculture of C. butyricum. When 10g of glucose in the media (1l) was supplied as a carbon source on continuous culture, mixed culture of C. butyricum and R. sphaeroides K-7 increased hydrogen evolution rate. Because considerable amount of glutamate was contained in waste water of glutamate fermentation, utilization of glutamate was examined in mixed culture. As a result of examination, production of hydorgen was slightly inhibited by high concentration of glutamate, more than 20mM, on continuous monoculture of R. sphaeroides K-7. On the other hand, both on continuous monoculture of C. butyricum and on mixed culture of C. butyricum and R. sphaeroides K-7, production of hydrogen was not inhibited by high concentration of glutamate such as 100mM. Hence this suggests that high concentration of waste water can be used as good substrate for hydrogen production on monoculture of C. butyricum and mixed culture of C. butyricum and R. sphaeroides K-7.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.90-100
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• 1985

The present study was designed to investigate cellular regulation of phosphate metabolism between catabolically repressed and derepressed states in yeast (Saccharomyces uvarum). The activities of various phospatases and the contents of phosphate compounds were detected according to the culture phase and various phosphate concentrations. As the results, Saccharomyces uvarum derepressed many phosphate metabolizing enzymes such as alkaline phosphatase, acid phosphatase and ATPase more than ten fold simultaneously during catabolic repression (phospgate and sugar starvation). At the same state, the amounts of orthophosphate, nucleotidic labile phosphate and acid soluble polypgosphate were increased, compared to basal levels of normally cultivated cells. $Mg^{++}-stimulated$ type among all phospatases was appeared to have most of the enzyme activity. It could be postulated that $K^+ -stimulated$ alkaline phosphatase was directly or indirectly correlated with the synthesis of acid insoluble polyphosphate $Mg^{++}-stimulated$ phosphatase with the degradation of polyphosphates. In case of cultivation in the medium supplemented with sugar and phosphate (catabolic derepression), phospgatase activities except for alkaline phosphatase were decreased rapidly through the progressive batch culture, After 12 hrs culture, at early exponential phase, the cellular accumulation of acid insoluble polyphosphate increased about 5 fold, compared to those of the starved cells. Under catabolic repression, it could be postulated that intracellular phosphate metabolism was regulated by derepressions of phosphatases. The function of polyphosphate system was shown to compensate the ATP/ADP system as phosphate donor and energy source especially during catabolic repression.