• Toxicological Research
• /
• 제19권2호
• /
• pp.147-152
• /
• 2003

We investigated antitumor activities of the ethanol extract from mushroom Phellinus linteus and Phellinus baumii on mulberry, oak and elm. in vitro test, the ethanol extract of mushroom cultivated on oak of Phellinus linteus showed highest activities about SK-OV-3, HCT15, XF498, SK-MEL-2 and A549. SK-OV-3 cell line showed 100% cytotoxicity in 100 $\mu\textrm{g}$/ml and HCT15 (98.39%), XF498 (89.62%), SK-MEL-2 (84.07%) and A549 (79.92%) cytotoxicity respectively. Also $IC_{50}$ showed 3.99 $\mu\textrm{g}$/ml to SK-OV-3 cell line and HCT15 (4.37 $\mu\textrm{g}$/ml), A549 (5.48 $\mu\textrm{g}$/ml), SK-MEL-2 (6.72 $\mu\textrm{g}$/ml), XF 498 (6.88 $\mu\textrm{g}$/ml). As those results, cultivated oak of Phellinus linteus showed a very low $IC_{50}$ value against SK-OV-3, HCT15, XF498, SK-MEL-2 and A549 cancer cell lines.

• 한국음향학회지
• /
• 제39권3호
• /
• pp.143-149
• /
• 2020

본 논문에서는 딥러닝(deep learning)을 이용하여 환경음 분류 시 전처리 단계에서 사용하는 특징 추출 방법이 콘볼루션 신경망의 분류 성능에 미치는 영향에 대해서 다루었다. 이를 위해 환경음 분류 연구에서 많이 사용되는 UrbanSound8K 데이터셋에서 멜 스펙트로그램(mel spectrogram), 로그 멜 스펙트로그램(log mel spectrogram), Mel Frequency Cepstral Coefficient(MFCC), 그리고 delta MFCC를 추출하고 각각을 3가지 분포로 스케일링하였다. 이 데이터를 이용하여 4 종의 콘볼루션 신경망과 이미지넷에서 좋은 성능을 보였던 VGG16과 MobileNetV2 신경망을 학습시킨 다음 오디오 특징과 스케일링 방법에 따른 인식률을 구하였다. 그 결과 인식률은 스케일링하지 않은 로그 멜 스펙트럼을 사용했을 때 가장 우수한 것으로 나타났다. 도출된 결과를 모든 오디오 인식 문제로 일반화하기는 힘들지만, Urbansound8K의 환경음이 포함된 오디오를 분류할 때는 유용하게 적용될 수 있을 것이다.

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

• 한국음향학회지
• /
• 제25권1호
• /
• pp.36-42
• /
• 2006

본 논문에서는 화자검증 시스템의 성능향상을 위해서 주성분 분석 (PCA) 기반 Mel-Frequency Discrete Wavelet Coefficients (MFDWC) 추출방법을 제안한다. 제안된 방법에서는 멜척도 (Mel-scale)를 근사화한 각 레벨 (level)의 각 노드 (node) 에너지를 계산하기 위해 기존의 평균치 대신 주성분 분석을 이용한 첫 번째 eigenvector를 이용한다. 이 eigenvecto.의 제곱의 합은 1로서 일반적인 가중 함수 (weighting function)의 조건을 만족하고, 또한 각 화자마다 서로 다른 값을 갖게 되므로, 화자의 특징을 더 잘 나타내는 MFDWC를 추출할 수 있다. 화자검증은 Gaussian Mixture Model (GMM) 기반의 백그라운드 모델과 화자 모델과의 점수를 비교하는 이진 결정 (binary decision) 방법을 이용하여 Universal 백그라운드 모델 (UBM)과 각 화자 모델의 값을 프레임단위로 비교하여 대상 화자의 수락/거부 여부를 결정하는 방법을 채택하였다. 특징 파라미터에 따른 화자 검증 성능변화를 확인하기 위하여 제안된 화자종속 가중함수를 이용한 MFDWC를 특징 파라미터로 이용한 경우와 Mel-Frequency Cepstral Coefficients (MFCC), Linear Predictive Cepstral Coefficients (LPCC), 기존의 MFDWC를 특징 파라미터로 이용한 경우에 대하여 성능비교실험을 수행한 결과 각각 $0.80\%,\;5.14\%,\; 6.69\%$의 향상된 성능을 나타내어 제안한 방법의 유효성을 확인할 수 있었다.

• Journal of Pharmaceutical Investigation
• /
• 제25권3호
• /
• pp.249-264
• /
• 1995

Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

• 융합신호처리학회논문지
• /
• 제7권3호
• /
• pp.116-121
• /
• 2006

본 논문에서는 다양한 잡음환경에서의 실시간 적응화 기법을 적용하기 위한 선결 과제로 다차원 음성 특정 벡터를 저차원으로 축소하는 방법을 제안한다. 제안된 방법은 특징 벡터를 확률 우도 값으로 매핑시켜 비선형적으로 축소하는 방법으로 음성 / 비음성의 분류는 우도비 검증 (Likelihood Ratio Test; LRT) 을 이용하여 분류하였다. 실험 결과 고차원 특징 벡터를 이용하여 분류한 결과와 대등하게 분류됨을 확인할 수 있었다. 그리고, 제안된 방법에 의해 검출된 음성 데이터를 이용한 음성인식 실험에서도 10차 MFCC(Mel-Frequency Cepstral Coefficient)를 사용하여 분류한 경우와 대등한 인식률을 보여주었다.

• ETRI Journal
• /
• 제28권4호
• /
• pp.502-505
• /
• 2006

A new class-based histogram equalization method is proposed for robust speech recognition. The proposed method aims at not only compensating the acoustic mismatch between training and test environments, but also at reducing the discrepancy between the phonetic distributions of training and test speech data. The algorithm utilizes multiple class-specific reference and test cumulative distribution functions, classifies the noisy test features into their corresponding classes, and equalizes the features by using their corresponding class-specific reference and test distributions. Experiments on the Aurora 2 database proved the effectiveness of the proposed method by reducing relative errors by 18.74%, 17.52%, and 23.45% over the conventional histogram equalization method and by 59.43%, 66.00%, and 50.50% over mel-cepstral-based features for test sets A, B, and C, respectively.

• Archives of Pharmacal Research
• /
• 제21권3호
• /
• pp.305-309
• /
• 1998

Human cytochrome P450 1A2 is one of the major cytochrome P450s in human liver. It is known to be capable of activating a number of carcinogens such as arylamines and heterocyclic amines. In order to develop the new bacterial mutagenicity test system with human P450, a full length of human P450 1A2 cDNA inserted into pCW bacterial expression vector was introduced to Escherichia coli WP2 uvrA strain which is a well-known E. coli strain for bacterial reverse mutagenicity assay. Expressed human P450 1A2 showed typical P450 hemoprotein spectra. Maximum expression was achieved at 48 hrs after incubating at $30^{\circ}C$ in terrific broth containing ampicillin, IPTG and other supplements. High level expression of P450 1A2 in E. coli WP2 uvrA membranes was determined in SDS-PAGE. The well-known mutagens 2-aminoanthracene and MElQ increased the revertant colonies of E. coli WP2 uvrA expressing human P450 1A2 without an exogenous rat hepatic post-mitochondrial supernatant (S9 fraction) in a dose-dependent manner. The results show that the functional expression of human P450 in bacterial mutagenicity tester strain will provide a useful tool for studying the mechanism of the mutagenesis and carcinogenesis of new drugs and environmental chemicals.

• International Journal of Fluid Machinery and Systems
• /
• 제9권1호
• /
• pp.47-55
• /
• 2016

The portable hydraulic turbine we previously developed for open channels comprises an axial flow runner with an appended collection device and a diffuser section. The output power of this hydraulic turbine was improved by catching and accelerating an open-channel water flow using the kinetic energy of the water. This study aimed to further improve the performance of the hydraulic turbine. Using numerical analysis, we examined the performances and flow fields of a single runner and a composite body consisting of the runner and collection device by varying the airfoil and number of blades. Consequently, the maximum values of input power coefficient of the Runner D composite body with two blades (which adopts the MEL031 airfoil and alters the blade angle) are equivalent to those of the composite body with two blades (MEL021 airfoil). We found that the Runner D composite body has the highest turbine efficiency and thus the largest power coefficient. Furthermore, the performance of the Runner D composite body calculated from the numerical analysis was verified experimentally in an open-channel water flow test.

• 한국음향학회지
• /
• 제40권2호
• /
• pp.176-182
• /
• 2021

본 논문은 다양한 손실 함수에 따른 Deep Nerual Network(DNN) 기반 음성 향상 모델의 성능을 비교 평가한다. 베이스라인 모델로는 음성의 위상 정보를 고려할 수 있는 복소 네트워크를 사용하였다. 손실 함수는 두 가지 유형의 기본 손실 함수, Mean Squared Error(MSE)와 Scale-Invariant Source-to-Noise Ratio(SI-SNR)를 사용하였으며 두 가지 유형의 지각 기반 손실 함수 Perceptual Metric for Speech Quality Evaluation(PMSQE)과 Log Mel Spectra(LMS)를 사용한다. 성능은 각 손실 함수의 다양한 조합을 사용하여 얻은 출력을 객관적인 평가와 청취 테스트를 통해 측정하였다. 실험 결과, 지각기반 손실 함수를 MSE 또는 SI-SNR과 결합하였을 때 전반적으로 성능이 향상되며, 지각기반 손실함수를 사용하면 객관적 지표에서 약세를 보이는 경우라도 청취 테스트에서 우수한 성능을 보임을 확인하였다.