• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.1-7
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• 2016

A range of techniques have been being developed to remove the volatile organic compounds from paining processes. High temperature decomposition of harmful VOCs using arc plasma has recently been proposed, and this work analyzed the extreme hot process by computer-aided fluid dynamics prior to the reactor design. Numerical simulations utilized the conservation equations of mass and momentum. The simulation showed that the fluid flowed down along the inner surface of the centrifugal reactor by forming intensive spiral trajectories. Although the high temperature gas generated by plasma influences the bottom of the reactor, no heat transfer in radial direction appeared. The decomposition efficiency of a typical VOCs, toluene, was found to be a maximum of 67% across the reactor, which was similar to the value (approximately 70%) for the lab-scale test.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.95-104
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• 2019

In this paper, we propose a method to design a generalized sinusoidal frequency modulated(GSFM) pulse that is robust to reverberation environment. GSFM pulses are a generalized form of SFM(Sinusoidal frequency modulated) pulses, which have the advantage of having a thumbtack ambiguity function with excellent range and Doppler resolution. However, the periodicity disappears during the generalization process, therefore, the detection performance is reduced in reverberation environment compared to SFM pulse with comb spectrum. In this paper, the trade-off relationship between the reverberation suppression performance of the SFM pulse and the range resolution performance of the GSFM pulse is analyzed by appropriately changing the parameter ${\rho}$ of the GSFM pulse. In order to verify the performance of the proposed GSFM pulse, the simulation was performed and it was confirmed that the proposed GSFM pulse has excellent distance resolution while detecting the slow Doppler target.

• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.290-301
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• 2019

The proposed algorithm deals with a detection problem of target echo for narrow-band continuous-wave active sonar in the underwater environment in this paper. In the active sonar systems, ping signal emitted for target detection produces a signal that consists of multiple reflections by many scatterers around, which is called reverberation. The proposed algorithm aims to detect the low-Doppler target echo in the reverberant environment. The proposed algorithm estimates the bearing, frequency, and temporal bases based on beamspace-domain multichannel nonnegative matrix factorization. In particular, the bases are divided into two basis groups - the reverberation group and the echo group, then the basis groups are estimated independently. In order to evaluate the proposed algorithm, a simulation with synthesized reverberation was performed. The results show that the proposed algorithm has enhanced performance than the conventional algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1545-1550
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• 2021

We propose an optimal variable step size adjustment method for the simplified subband affine projection algorithm (Simplified SAP; SSAP) in a subband structure based on a polyphase decomposition technique. The proposed method provides an optimal step size derived to minimize the mean square deviation(MSD) at the time of updating the coefficients of the subband adaptive filter. Application of the proposed optimal step size in the SSAP algorithm using colored input signals ensures fast convergence speed and small steady-state error. The results of computer simulations performed using AR(2) signals and real voices as input signals prove the validity of the proposed optimal step size for the SSAP algorithm. Also, the simulation results show that the proposed algorithm has a faster convergence rate and good steady-state error compared to the existing other adaptive algorithms.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.509-516
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• 2010

This study investigates characteristics of diesel degradation and variations of microbial community with the soil enrichment cultures. The cultures has yellow(YE-5) and transparent color's(WH-5) colony on solid plate medium. The bacillus type of YE-5 and WH-5 cultures showed diesel degradation at the rate of 99.07mg-Diesel/$L{\cdot}day$ and 57.82mg-Diesel/$L{\cdot}day$ in the presence of 1%(v/v) initial diesel concentration. Diesel degradation was 1.7 times faster than WH-5 culture. YE-5 or WH-5 culture could degrade a wide range of diesel compounds from $C_8$ to $C_24$. Microbial community analysis by PCR-DGGE technique shows that Psedomonas, Klebsiella, Escherichia and Stenotrophomonas as proteobacteria take role on the diesel degradation. uncultured Senotrophomonas sp. was only detected with YE-5 culture. It is concluded that proper combination of the microorganism should be present to stimulate the degradation of diesel and further studies are recommended for the effect of uncultured Senotrophomonas sp. or Escherichia hermannii on diesel degradation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.663-668
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• 2000

To develop natural intermediate flavoring substances, optimal processing conditions and qualities for two stage enzyme hydrolysate (TSEH) from low-utilized small longfinned squid were investigated. The optimal conditions for TSEH method were found as digestion with Alcalase (0.2% w/w-sample, pH 8.0) at 55$^{\circ}C$ 3 hours at the 1st stage and with Neutrase (exo-peptidase, 0.2% w/w-sample, pH 6.0) at 45$^{\circ}C$ for 2~3 hours at the 2nd stage. Among the method of water extract, autolytic extract and various kinds yields, transparency and organoleptic taste. From the results of chemical experiments and sensory evaluation, longfinned squid TSEH is flavorable as the natural intermediate taste-active substances for fisheries products such as soup base, squid-taste pasty and snacks.

• KSBB Journal
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• v.18 no.3
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• pp.174-179
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• 2003

The bacterium NFQ-1 capable of utilizing quinoline (2,3-benzopyridine) as the sole source of carbon, nitrogen and energy was enriched and isolated from soil samples of dead coal pit areas. Strain NFQ-1 was identified as Pseudomonas nitroreducens NFQ-1 by BIOLOG system, and assigned to Pseudomonas sp. NFO-1. Pseudomonas sp. NFQ-1 was used with the concentration range of 1 to 10 mM quinoline. Strain NFQ-1 could degrade 2.5 mM quinoline within 9 hours of incubation. Initial pH 8.0 in the culture was reduced to 6.8, and eventually 7.0 as the incubation was proceeding. 2-Hydroxyquinoline, the first intermediate of the degradative pathway, accumulated transiently in the growth medium. The highest concentration of quinoline (15 mM) in this work inhibited cell growth and quinoline degradation. Pseudomonas sp. NFQ-1 was able to utilize various quinoline derivatives and aromatic compounds including 2-hydroxyquinoline, p-comaric acid, benzoic acid, p-cresol, p-hydroxybenzoate, protocatechuic acid, and catechol. The specific activity of catechol oxygenases was determined to approximately 184.7 unit/㎎ for catechol 1.2-dioxygenase and 33.19 unit/㎎ for catechol 2,3-dioxygenase, respectively. As the result, it showed that strain NFQ-1 degraded quinoline via mainly orthp-cleavage pathway, and in partial meta-cleavage pathway.

• Journal of Soil and Groundwater Environment
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• v.11 no.1
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• pp.1-6
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• 2006

The analysis of functional population and its dynamics on the environment is essential for understanding bioremediation in environment. Here, we report a method for oligonucleotide microarray for the monitoring of aliphatic and aromatic degradative genes. This microarray contained 15 unique and group-specific probes which were based on 100 known genes involved pathways in biodegradation. Hybridization specificity tests with pure cultures, strain Pseudomonas aeruginosa KCTC 1636 indicated that the designed probes on the arrays appeared to be specific to their corresponding target genes. It was found that the presence of 8 genes encoding alkane, naphthalene, biphenyl, pyrene (PAH ring-hydroxylating) degradation pathway could be detected in oil contaminated soil sample. Therefore, the findings of this study strongly suggest that oligonucleotide microarray is an effective diagnostic tool for evaluating biodegradation capability in oil contaminated subsurface environment.

• Journal of KIISE
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• v.41 no.12
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• pp.1050-1057
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• 2014

Electroencephalogram (EEG)-based brain-computer interfaces (BCI) can be used for a number of purposes in a variety of industries, such as to replace body parts like hands and feet or to improve user convenience. In this paper, we propose a method to decompose and extract motor imagery EEG signal using Empirical Mode Decomposition (EMD) and Fast Fourier Transforms (FFT). The EEG signal classification consists of the following three steps. First, during signal decomposition, the EMD is used to generate Intrinsic Mode Functions (IMFs) from the EEG signal. Then during feature extraction, the power spectral density (PSD) is used to identify the frequency band of the IMFs generated. The FFT is used to extract the features for motor imagery from an IMF that includes mu rhythm. Finally, during classification, the Support Vector Machine (SVM) is used to classify the features of the motor imagery EEG signal. 10-fold cross-validation was then used to estimate the generalization capability of the given classifier., and the results show that the proposed method has an accuracy of 84.50% which is higher than that of other methods.

• Korean Journal of Microbiology
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• v.30 no.1
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• pp.47-52
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• 1992

This study describes isolation and identification of a soil bacterium which is degradable of phosphinothricin and improvement of the isolated strain by using mutagenesis and spheroplast fusion. The experiment was performed to search for a possibility of development of a new strain which is both PPT-degradable and glyphosate-resistant by using interspecies cell fusion between the PPT-degrading bacterium. Pseudornonu.\ puucimohlis and a glyphosate -resistant strain, Pseudornonu.~ cc,pucicl. Auxotrophic mutants were obtained by the treatement of P. puucimohili.\ with ethylmethanosulfate, and used to cell fusion. Lysozyme and EDTA were used to spheroplast formation and regeneration rates :)f the spheroplast were 6.5'%1 in P. pauc.irnohili.\ and 8.8% in P.ci,j~u[,i(lr, espctively. Polyethylenglycol 5.000 was used to cell fusion as fusogen. The fusant\ulcorner F1. F2. F\ulcorner and F4 werc- obtained by the intra- and interspecies cell fusion. The fusant Fl of intraspecies cell fusion was higher to the wild type by 1 I'%l in PPT degrading ability, and the fusant F3 of inierspesis cell fusion developed plyphosatc-resistant and PPI-dcgrading ability which were propertics of two parental strains.