• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.413-419
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• 2007

The optimal power flow (OPF) problem was introduced by Carpentier in 1962 as a network constrained economic dispatch problem. Since then, it has been intensively studied and widely used in power system operation and planning. In the past few decades, many stochastic optimization methods such as Genetic Algorithm (GA), Evolutionary Programming (EP), and Particle Swarm Optimization (PSO) have been applied to solve the OPF problem. In particular, PSO is a newly proposed population based stochastic optimization algorithm. The main idea behind it is based on the food-searching behavior of birds and fish. Compared with other stochastic optimization methods, PSO has comparable or even superior search performance for some hard optimization problems in real power systems. Nowadays, some modifications such as breeding and selection operators are considered to make the PSO superior and robust. In this paper, we propose the Modified PSO (MPSO), in which the mutation operator of GA is incorporated into the conventional PSO to improve the search performance. To verify the optimal solution searching ability, the proposed approach has been evaluated on an IEEE 3D-bus test system. The results showed that performance of the proposed approach is better than that of the standard PSO.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.33-38
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• 2000

In order to produce ascorbic acid-2-phosphate from ascorbic acid, bacteria capable of transforming ascorbic acid to ascorbic acid-2-phosphate were isolated from soils and the stock cultures in our laboratory. Among them, a newly isolated bacterium LSH-3 having the best ability of producing ascorbic acid-2-phosphate was selected and partially identified as Pseudomonas sp. The optimum conditions for the production of ascorbic acid-2-phosphate from ascorbic acid and using its resting cells as the source os enzyme were investigated. The results were summarized as follows: The optimum cultivation time and the cell weight for the production of ascorbic acid-2-phosphate was 14 hours and 100g/I(wet weight), respectively. And 0.1%(v/v) Trition X-100 was the most effective surfactant. The optimum concentrations of ascorbic acid and pyrophosphate were 400mM and 500mM, respectively, which led to produce 14.54g/I of ascorbic acid-2-phosphate. The most effective buffer was 50mM sodium acetate. The optimum pH and temperature were 4.5 and $40^{\circ}C$, respectively. Under the above conditions, 17.71 g/I of ascorbic acid-2-phosphate was produced from ascorbic acid after 32 hour-incubation, which corresponded to 17.5% of conversion rate based on ascorbic acid.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.474-481
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• 2009

A novel microorganism, designated as LG12, was isolated from soil based on its ability to use acrylic acid as the sole carbon source. An electron microscopic analysis of its morphological characteristics and phylogenetic classification by 16S rRNA homology showed that the LG12 strain belongs to Rhodococcus erythropolis. R. erythropolis LG12 was able to metabolize a high concentration of acrylic acid (up to 40 g/l). In addition, R. erythropolis LG12 exhibited the highest acrylic acid-degrading activity among the tested microorganisms, including R. rhodochrous, R. equi, R. rubber, Candida rugosa, and Bacillus cereus. The effect of the culture conditions of R. erythropo/is LG12 on the production of 3-hydroxypropionic acid (3HP) from acrylic acid was also examined. To enhance the production of 3HP, acrylic acid-assimilating activity was induced by adding 1 mM acrylic acid to the culture medium when the cell density reached an $OD_{600}$ of 5. Further cultivation of R. erythropo/is LG 12 with 40 g/l of acrylic acid resulted in the production of 17.5 g/l of 3HP with a molar conversion yield of 44% and productivity of 0.22 g/l/h at $30^{\circ}C$ after 72 h.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1993-2005
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• 2019

Thermophilic anaerobic digestion (TAD) is characterized by higher biogas production rates as a result of assumedly faster microbial metabolic conversion rates compared to mesophilic AD. It was hypothesized that the thermophilic microbiome with its lower diversity than the mesophilic one is more susceptible to disturbances introduced by alterations in the operating factors, as an example, the supply of nitrogen-rich feedstock such as poultry manure (PM). Laboratory scaled TAD experiments using cattle slurry and increasing amounts of PM were carried out to investigate the (in-) stability of the process performance caused by the accumulation of ammonium and ammonia with special emphasis on the microbial community structure and its dynamic variation. The results revealed that the moderate PM addition, i.e., 25% (vol/vol based on volatile substances) PM, resulted in a reorganization of the microbial community structure which was still working sufficiently. With 50% PM application, the microbial community was further stepwise re-organized and was able to compensate for the high cytotoxic ammonia contents only for a short time resulting in consequent process disturbance and final process failure. This study demonstrated the ability of the acclimated thermophilic microbial community to tolerate a certain amount of nitrogen-rich substrate.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1484-1494
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• 2017

We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

• Journal of Internet Computing and Services
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• v.3 no.4
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• pp.1-9
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• 2002

As a XML Schema has been settled to W3C as standard at May. 2001 and technologies like as XML. Xpath and NameSpace related with XML has been developing. XML is becoming the standard of the new document exchanging. Due to the ability expressing various types of documentstructure through XML, ebXML, RosettaNet, and BizTalk are using XML as a core technology in the part of e-Business, To make the task automatically in the B2B EC now, a standard XML document is needed. Internal documents in each company should be transformed differently without any loss to work with other companies. In this paper, transforming XML document based on JAVA servlet is considered as realization of a XML system to exchange documents safely.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.360-365
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• 2003

The ability of 19 lactic acid bacteria to produce hydroxy fatty acids (HFAs) from unsaturated food fatty acids (USFAs) was tested. HFAs are related to human ailments, including steatorrhea. All the cultures produced HFAs from USFAs, unless their growth was inhibited by free USFAs. Lactococcus lactis subsp. lactis KFRI 131 converted oleic, linoleic, and linolenic acid into 10-hydroxyoctadecanoic acid (10-HODA), 10-hydroxyoctadecaenoic acid (10-HODEA), and 10-hydroxyoctadecadienoic acid (10-HODDEA), respectively. Both a USFA and a surfactant were needed for the bacterium to convert the fatty acid into the corresponding HFA. It was apparent that the production of 10-HODA was growth-related, while that of 10-HODDEA was not. It was unclear whether the production of 10-HODEA was growth-related.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1085-1091
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• 2014

Matrix metalloproteinases (MMPs) are a family of zinc dependent extracellular matrix (ECM) remodelling endopeptidases having the ability to degrade almost all components of extracellular matrix and implicated in various physiological as well as pathological processes. Carcinogenesis is a multistage process in which alteration of the microenvironment is required for conversion of normal tissue to a tumour. Extracellular matrix remodelling proteinases such as MMPs are principal mediators of alterations observed in the microenvironment during carcinogenesis and according to recent concepts not only have roles in invasion or late stages of cancer but also in regulating initial steps of carcinogenesis in a favourable or unfavourable manner. Establishment of relationships between MMP overproduction and cancer progression has stimulated the development of inhibitors that block proteolytic activity of these enzymes. In this review we discuss the MMP general structure, classification, regulation roles in relation to hallmarks of cancer and as targets for therapeutic intervention.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1680-1686
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• 2015

Inhibition of 4-nitroquinoline-1-oxide (4-NQO) genotoxicity by a probiotic strain of Lactobacillus rhamnosus (IMC501) was assessed by the prokaryotic short-term bioassay SOSChromotest, using Escherichia coli PQ37 as the target organism. Results showed the ability of strain IMC501 to rapidly and markedly counteract, in vitro, the DNA damage originated by the considered genotoxin. The inhibition was associated with a spectroscopic hypsochromic shift of the original 4-NQO profile and progressive absorbance increase of a new peak. IR-Raman and GC-MS analyses confirmed the disappearance of 4-NQO after contact with the microorganism, showing also the absence of any genotoxic molecule potentially available for metabolic activation (i.e., 4-hydroxyaminoquinoline-1-oxide and 4-nitrosoquinoline-1-oxide). Furthermore, we have shown the presence of the phenyl-quinoline and its isomers as major non-genotoxic conversion products, which led to the hypothesis of a possible pattern of molecular transformation. These findings increase knowledge on lactobacilli physiology and contribute to the further consideration of antigenotoxicity as a nonconventional functional property of particular probiotic strains.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.184-190
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• 1998

Most buildings and factories are supplied with electric power by three-phase four-wire low voltage electric distribution system. This method pollutes the neutral line and utility sources with harmonic currents. Today, development of power conversion technology and the popularization of computer cause the neutral current to become serious. In this paper, a novel three-phase four-wire active filter is proposed to solve these harmonic problems has two purposes. The first purpose of the proposed active filiter is that the phase current has a sinusoidal waveform shape under the nonlinear load. The second purpose of the proposed active filiter is that the current on the neutral line become zero under the unbalanced power source and under the varring load conditions. The ability of the shunt active filiter has been proved to be excellent through simulations under the varring load conditions.