• 말소리와 음성과학
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• 제7권4호
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• pp.27-33
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• 2015

This paper proposes an audio event classification method using Deep Neural Networks (DNN). The proposed method applies Feed Forward Neural Network (FFNN) to generate event probabilities of ten audio events (dog barks, engine idling, and so on) for each frame. For each frame, mel scale filter bank features of its consecutive frames are used as the input vector of the FFNN. These event probabilities are accumulated for the events and the classification result is determined as the event with the highest accumulated probability. For the same dataset, the best accuracy of previous studies was reported as about 70% when the Support Vector Machine (SVM) was applied. The best accuracy of the proposed method achieves as 79.23% for the UrbanSound8K dataset when 80 mel scale filter bank features each from 7 consecutive frames (in total 560) were implemented as the input vector for the FFNN with two hidden layers and 2,000 neurons per hidden layer. In this configuration, the rectified linear unit was suggested as its activation function.

• Toxicological Research
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• 제19권1호
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• pp.45-50
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• 2003

The purpose of this study was to determine the role of substituted groups in phenolic compounds to develop an anticancer agent having strong cytotoxicity against cancer cells but weak against normal cells. The phenolic compounds used in this study were gallic acid and ferulic acid with hydroxyl and carboxyl groups, syringic acid with hydroxyl, carboxyl and methoxy groups, and pyre-gallol with hydroxyl groups. Cytotoxicities of these compounds were evaluated by MTT assay for cell viability and XTT assay for cell adhesion activity in normal human skin fibroblast (Detroit 551) and human skin melanoma (SK-MEL-3) cells. Syringic acid, gallic acid and ferulic acid decreased the cell viability and cell adhesion activity in SK-MEL-3 cells but not in Detroit 551 cells while pyrogallol decreased in both cells. The susceptibility of cell viability based on the $IC_{50}$ values of MTT assay in Detroit 551 cells was in the following order: pyrogallol > gallic acid > ferulic acid > syringic acid, while it was in SK-MEL-3 cells: Syringic acid > progallol > ferulic acid > gallic acid. These results suggest that carboxyl and methoxy groups of these compounds play an important role in selectivity of cytotoxicity in normal and cancer cells.

• 한국ITS학회 논문지
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• 제11권1호
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• pp.86-91
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• 2012

다양한 잡음환경에 노출되는 텔레메틱스 기반의 음성 통화 시스템에서 고품질의 통화 품질을 제공하기 위해서는 저연산량을 가지며 효과적으로 배경 잡음을 제거할 수 있는 잡음제거 알고리즘이 요구된다. 본 논문에서는 Mel-Filter 기반의 잡음제거 알고리즘을 제안하며, 제안된 알고리즘을 기존 잡음제거 알고리즘들과 비교하여 설명한다. 자동차 잡음과 배블 잡음 환경에서 잡음제거 알고리즘의 성능 측정 결과, 제안된 Mel-Filter 기반의 잡음제거 알고리즘이 기존 잡음제거 알고리즘들에 비해 비슷한 PESQ 성능에 적은 연산량을 가지는 장점을 가지고 있으며, 제안된 잡음제거 알고리즘이 텔레메틱스 단말기에서 효과적으로 잡음을 제거할 수 있음을 입증하였다.

• 한방안이비인후피부과학회지
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• 제20권3호
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• pp.14-28
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• 2007

Objective : Hwagi-Jokyeong-Tang (化氣調經湯, HJT) was described in DongeuiBogam(東醫寶鑑). This remedy has been used to treat patients with Naryeok, which is similar as tuberculous cervical lymphadenitis in western medicine. Methods : In this study, the present author investigated the effects of HJT on on Human HaCaT keratinocyte and malignant melanoma cells such as SK-MEL-2 and B16F10 in terms of cell viabilities, proliferations, DPPH free radical scavenging activities, oxygen free radical productions and inhibitory action on elastase activities. Results : HJT acceleated proliferation of HaCaT keratinocytes dose-dependantly. HJT also prevented cell death of HaCaT induced by Hydrogen peroxide, which products oxygen free radicals. On the contrary, HJT did not affect proliferations of SK-MEL-2 or B16F10. In addition, HJT was shown to have DPPH free radical scavenging activities and also have inhibitory effects on elastase activities too. On the fluorescent examinations, the present author know that HJT did not affect production levels of oxygen free radicals in malignant melanoma cell, SK-MEL-2. Conclusions : These results suggest that HJT has possibilities of usage for functional cosmetics which have skin regeneration or prevention from skin tissue injury.

• The Journal of the Acoustical Society of Korea
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• 제13권1E호
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• pp.71-81
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• 1994

본 논문에서는 line spectrum pair (LSP)의 의사 켑스트럼 표현을 제안하고 이 의사 켑스트럼에 켑스트럼 lifter를 적용하여 얻은 특징 벡타를 이용하는 음성 인식 시스템의 성능을 평가한다. 의사 켑스트럼 표현은 LSP와 LPC 켑스터럼 사이의 관계로부터 근사적으로 유도된다. 이때 음성 인식 시스템의 성능을 더욱 향상 시키기 위하여 root-power-sums lifter, general exponential lifter (GEL), 그리고 bandpass lifter 등과 같은 켑스터럼 liter가 의사 켑스터럼에 적용된다. 또한 mel 주파수로의 변환도 행해진다. 인식 결험 결과, GEL로 liftering된 mel 주파수 의사 켑스터럼이 가장 좋은 성능을 나타내며, LSP에 비해 5~6dB정도의 신도대잡음비의 개선을 얻을 수 있다.

• Biomolecules & Therapeutics
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• 제9권4호
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• pp.249-257
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• 2001

The effect of oxidative stress on the alterations of different antioxidant enzyme activities was investigated in human skin melanoma cell line (SK-MEL-2). Oxidative stress was induced by the exposure to hydrogen peroxide ($H_2O$$_2$). SK-MEL-2 cells were treated with antioxidants such as vitamin E and selenomethionine in combination with $H_2O$$_2$. SK-MEL-$_2$ cells were exposed to various concentrations of $H_2O$$_2$ and measured the time course of changes in cell viability and antioxidant enzyme activities for 24 hr. Oxidative stress was induced by the exposure to 2.5mM hydrogen peroxide ($H_2O$$_2$) resulted in declining significantly for 24 hr. GPX and CAT activities peaked at 3 hr and returned to control levels by 24 hr. On the contrary, SOD activity was inactive before 6 hr but recovered at 24 hr. In case vitamin E (Vit E) and selenomethionine (Se-Met) were used at nontoxic concentrations (25$\mu$M Vit E/500$\mu$M Se-Met) to oxidative stress was induced by the exposure to hydrogen peroxide ($H_2O$$_2$) led to a 3- and 5-fold increase on the viability comparing to control and caused an increase in GPX activity respectively.

• The Korean Journal of Physiology and Pharmacology
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• 제2권4호
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• pp.411-417
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• 1998

The role of phospholipase ($A_2\;PLA_2$) in tumor cell growth was investigated using SK-N-MC human neuroblastoma cells. 4-Bromophenacyl bromide (BPB) and mepacrine (Mep), known $PLA_2$ inhibitors, suppressed growth of the tumor cells in a dose-dependent manner without a significant cytotoxicity. Melittin (Mel), a $PLA_2$ activator, enhanced the cell growth in a concentration-dependent fashion. The growth-enhancing effects of Mel were significantly reversed by the co-treatment with $PLA_2$ inhibitors. In addition, Mel induced intracellular $Ca^{2+}$ release from internal stores like as did serum, a known intracellular $Ca^{2+}$ agonist in the tumor cells. Intracellular $Ca^{2+}$ release induced by these agonists was significantly blocked by $PLA_2$ inhibitors at growth-inhibitory concentrations. Arachidonic acid (AA), a product of the $PLA_2-catalyzed$ reaction, induced cell growth enhancement and intracellular $Ca^{2+}$ release. These effects of AA were significantly blocked by BAPTA/AM, an intracellular $Ca^{2+}$ chelator. Taken together, these results suggest that the modulation of $PLA_2$ activity may be one of the regulatory mechanisms of cell growth in human neuroblastoma cells. Intracellular $Ca^{2+}$ may act as a key mediator in the $PLA_2-induced$ growth regulation.

• Carbon letters
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• 제9권3호
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• pp.200-202
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• 2008

In order to improve the thermal stability of PAN-based electrospun fibers, AP-PER-MEL and $TiO_2$ were added in to the fibers as additives. The polymer composite with uniformly mixed additional agents was obtained. In case of non-treated sample, the fibers were burn off completely with high rate within $620^{\circ}C$. But in case of treated samples (EF-M and EF-MT), it is sure that the thermal stability was improved by studying TGA data and ISO flammability test about 20 and 30%, respectively. A synergy effect of adding two kinds of agents (AP-PER-MEL and $TiO_2$) into PAN-based electrospun fibers was confirmed. Through SEM images, it is confirmed that the fiber shape can be kept even after addition of agents (AP-PER-MEL and $TiO_2$). Finally the thermal stability of fibers was largely developed with keeping the nature of PAN-based fibers effectively.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1204-1211
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• 2019

Fungal exopolysaccharides are important natural products having diverse biological functions. In this study, exopolysaccharides from Fomitopsis castanea mycelia (FEPS) were prepared, and the highest mushroom tyrosinase inhibitory activity was found. FEPS were prepared from cultivation broth by ethanol precipitation method. The extraction yield and protein concentration of FEPS were 213.1 mg/l and 0.03%, respectively. FEPS inhibited mushroom tyrosinase with the half maximal inhibitory concentration ($IC_{50}$) of 16.5 mg/ml and dose-dependently inhibited cellular tyrosinase activity (63.9% at $50{\mu}g/ml$, and 83.3% at $100{\mu}g/ml$) in the cell-free extract of SK-MEL-5 human melanoma cell and ${\alpha}$-melanocyte-stimulating hormone (${\alpha}-MSH$)-stimulated melanin formation in intact SK-MEL-5 human melanoma cell. The $IC_{50}$ of FEPS against NO production from RAW264.7 macrophage cells was $42.8{\pm}0.64{\mu}g/ml$. By in vivo study using a zebrafish model, exposure of FEPS at $400{\mu}g/ml$ to dechorionated zebrafish embryos for 18 h decreased the pigment density, compared to that without FEPS-treated control.

• 디지털산업정보학회논문지
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• 제20권2호
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• pp.27-36
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• 2024

Accidents or disease can lead to acquired voice dysphonia. In this case, we propose a new input interface based on eye movements to facilitate communication for patients. Unlike the existing method that presents the English alphabet as it is, we reorganized the layout of the alphabet to support the Korean alphabet and designed it so that patients can enter words by themselves using only eye movements, gaze, and blinking. The proposed interface not only reduces fatigue by minimizing eye movements, but also allows for easy and quick input through an intuitive arrangement. For natural communication, we also implemented a system that allows patients who are unable to speak to communicate with their own voice. The system works by tracking eye movements to record what the patient is trying to say, then using Glow-TTS and Multi-band MelGAN to reconstruct their own voice using the learned voice to output sound.