• The Journal of the Acoustical Society of Korea
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• v.34 no.3
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• pp.177-183
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• 2015

This paper proposes a robust nonlinear acoustic echo canceller (NAEC) which is effective for modeling the nonlinearity of a speaker module and the long acoustic echo path within a speech communication environment. The proposed NAEC utilizes a sigmoid pre-processor for modeling the speaker nonlinearity and a partitioned block frequnecy-domain adaptive filter for identifying the acoustic echo path with small delay. Simulation results confirmed that the proposed algorithm achieves excellent performance with much lower computational complexity than the previous NAEC.

• Korean Journal of Plant Resources
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• v.1 no.1
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• pp.23-32
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• 1988

The Plants medicinal resources of Mt. Mohu were investigated 12 times from July 1, 1987 to July 28, 1988. In order to analyze the vegetation of Mt. Mohu area,herb plants structure and distribution. Herb plants of Mohu Mt. consisted of 58families, 230 species in all. The resources of important herb drugs were plant-aginaceae, Labiatae, Amarantaceae, Campanulaceae, Asclepiaclaceae, Leguminosae,Gentianaceae, Liliaceae, lilicaceae, Dioscoreaceae, Compositae, Caprifoliaceae,Ranuncvlaceae, Lauraceae, Lardizabalaceae, Araliaceae, Solanaceae, Cornaceae,Fagaceae and Rosaceae. The herb drugs were comparatively more than in othermountains in our country.

• The Korean Journal of Community Living Science
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• v.24 no.1
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• pp.27-36
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• 2013

This study was performed to investigate the antimicrobial effect against food-borne pathogens of Sanguisorbae officinalis L. ethanol extract. The antimicrobial activity of the ethanol extract was determined using a paper disc-diffusion method and the diameter of the clear zone was measured. The diameters of the clear zone in the presence of 10 mg of the ethanol extract were the maximum against Staphylococcus aureus among the tested 4 gram-positive bacteria and Pseudomonas aeruginosa among the tested 7 gram-negative bacteria. Analysis of the minimum inhibition concentrations (MIC) showed that the ethanol extract exhibited a similar efficacy as sorbic acid, well-known chemical preservatives. The growth inhibitory effects of the ethanol extract in the concentrations of 250, 500, 1,000 and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Bacillus subtilis, Salmonella Typhimurium and Pseudomonas aeruginosa. The growth of the microorganisms was significantly (p<0.05) inhibited by the ethanol extract in the concentrations higher than 250 mg/L. Thus, the results of the present study demonstrate that the ethanol extract exhibits antimicrobial effects against food-borne pathogens, suggesting that Sanguisorbae officinalis L. could be used as natural antibacterial agent in food.

• Journal of fish pathology
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• v.18 no.3
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• pp.227-237
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• 2005

To obtain antimicrobial compounds against fish pathogenic bacteria from natural products, 80% methanolic extracts from 14 species of medicinal plant were screened for antimicrobial activity against fish pathogenic bacteria, Edwardsiella tarda and Vibrio anguillarum. Among them, Glycyrrhiza glabra, Rhus vemiciflua and Sanguisorba officinalis were effective for growth inhibition of Gram-negative bacteria, both E. tarda YSF and V. anguillarum YSR. Through the activity-guided isolation for R. verniciflua extract that exhibited the highest antimicrobial activity among three extracts, one antimicrobial compound (1) was isolated and identified as methyl-3,4,5-trihydroxybenzoate, or methyl gallate. This compound significantly inhibited the growth of tested strains of both E. tarda and V. anguillarum exhibiting MIC of 1 mg/ml for each strain.

• Korean Journal of Pharmacognosy
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• v.48 no.2
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• pp.166-171
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• 2017

We have studied the antifungal effect of 19 medicinal plants with paper disc diffusion method against candida albicans. As a result, Sanguisorba officinalis L., Cinnamomum cassia, Rheum coreanum, Perilla frutescens and Eugenia caryophyllata have been found to be effective against C. albicans. Among these, Sanguisorba officinalis L. was most effective at 24 hours and 48 hours. Its clear zone diameter was 17 mm for 24 hours and 16 mm for 48 hours. The antifungal activity of the solvent fraction of Sanguisorba officinalis L. by n-hexane, chloroform, ethyl acetate and n-butanol was the best for the chloroform fraction of 28 mm for 24 hours and 18 mm for 48 hours. The MIC concentration of the chloroform fraction was $80{\mu}g/50{\mu}l$ at 24 hours and $240{\mu}g/50{\mu}l$ at 48 hours.

• The Journal of the Acoustical Society of Korea
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• v.35 no.3
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• pp.234-242
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• 2016

In this paper, an on-line noise coherence estimation algorithm for binaural speech enhancement system is proposed. A number of noise Power Spectral Density (PSD) estimation algorithms based on the noise coherence between two microphones have been proposed to improve the speech enhancement performance. In the conventional algorithms, the noise coherence was characterized using a real-valued analytic model. However, unlike the analytic model, the noise coherence between the two microphones is time-varying in real environments. Thus, in this paper, the noise coherence is updated in accordance with the variation of the acoustic environment to track the realistic noise coherence. The noise coherence can be updated only during the absence of speech, and the simulation results demonstrate the superiority of the proposed algorithm over the conventional algorithms based on the analytic model.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.205-212
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• 2016

In this paper, we implement the development platform of multichannel digital hearing aid algorithm using Simulink provided by Matlab. The digital hearing aids are considered medical devices designed to compensate for hearing loss, they need to be correctly selected, to help a person who has difficulty in hearing. The development platform that implemented in this paper, includes WOLA filterbank for analysis/synthesis of input signal, Wide dynamic range compression for hearing loss compensation and adaptive filter for feedback cancellation. Using the development platform, algorithm parameters for each block can be set depending on the hearing aid user. Thus it is possible to test the algorithm before the machine language. As a result, the time for algorithm development can be saved and performance and computational complexity can be optimized.

• Journal of Haehwa Medicine
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• v.21 no.2
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• pp.63-72
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• 2013

To develop a new anti-skin aging cosmetics or functional foods by using antioxidative activity and collagenase inhibitor, a potent collagenase or elastase inhibitor was screened from various extracts of medicinal plants and its optimal extraction condition was investigated. And antioxidative activity, antimicrobial activity and inhibitory of effect against collagenase activity were investigated. In the these results, we selected the Sanguisorba (Sanguisorba officinalis L.) that presents a potential biological activities. Sanguisorba which is very rich in triterpenoid saponin and tannins was recently reported its anti-oxidant activities and phytoestogenic activities in vivo test and many clinical studies. The experiments were carried out in vitro to determine anti-oxidant activities of Sanguisorba extracts on DPPH radical scavenging activity assay, Superoxidase scavenging activity assay, Elastase and collagenase activity assay. It show that the Sanguisorba extracts have the most significant anti-oxidant on free radical scavenging activity assay, and also inhibited significantly activities of elastase, collagenase. Further, Sanguisorba extracts are activated Type I collagen protein expression in CCD-986sk cells. These result suggest that the Sanguisorba extracts on DPPH radical scavenging activity assay, Superoxidase scavenging activity assay, elastase and collagenase activity assay, Type I collagen protein expression in CCD-986sk cells effected could be developed cosmetic ingredients for anti-aging.

• The Journal of the Acoustical Society of Korea
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• v.36 no.5
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• pp.353-360
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• 2017

The single sensor based acoustic reflection control system separates the incident and reflected signals from the single sensor output, and reduces the reflected signal by generating an out-of-phase signal from the incident signal component. In this paper, we propose an optimal filter design method for a single sensor based reflection control system. In the proposed method, it is shown that the optimum control filter design is possible by using the measured impulse responses of the reflection and control paths. The reflection control algorithm based on the proposed optimal filter achieves better performance than the conventional adaptive filter-based algorithm and effectively controls the reflection without the initial convergence time. We performed computer simulations using the signals obtained in a 1-dimensional acoustic duct environment, and from the simulation results, it was confirmed that the proposed optimal filter has robust performance even in noisy environment.

• Korean Journal of Medicinal Crop Science
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• v.24 no.4
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• pp.303-308
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• 2016

Background: This study aimed to investigate the antioxidat and antimicrobial activities of the methanol extract and its fractions prepared from the roots of Sanguisorba officinalis L. Methods and Results: The antioxidant activities were compared by evaluating the DPPH radical and nitric oxide (NO) scavenging ability. Measurement of DPPH radical scavenging ability showed that the $SC_{50}$ values of the ethyl acetate fraction was $3.85{\mu}g/m{\ell}$. The ethyl acetate fraction exhibited the most effective DPPH radical scavenging ability compared with the other samples. As for the NO scavenging ability, at all tested concentrations, the ethyl acetate fraction showed a higher scavenging activity than that of the extract and other fractions. These results are related to the total phenolic compound and flavonoid contents of the ethyl acetate fraction. Antimicrobial activity against foodborne pathogens was investigated using the disc diffusion assay. The ethyl acetate fraction showed the highest antimicrobial activity against gram-positive Staphylococcus aureus and Bacillus cereus. However, the chloroform fraction had a higher antimicrobial activity against gram-negative Vibrio vulnificus than that of the extract and other fractions. Conclusions: The results show that the ethyl acetate fraction had a higher antioxidant as well as antimicrobial activity, than did the other samples. Therefore, the ethyl acetate fraction has potential application in the food industry.