• Title/Summary/Keyword: 첨도

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Study on the Surface Morphology and Control of Impurity by Organic Additive for Tin electro-refining (주석 전해정련에서 유기첨가제에 따른 표면형상 및 전해불순물 제어에 관한 연구)

  • Park, Sung Cheol;Son, Seong Ho;Kim, Yong Hwan;Han, Chul Woong;Lee, Ki-Woong
    • Resources Recycling
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    • v.25 no.4
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    • pp.49-53
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    • 2016
  • The electro-refining process was performed to purify the casted tin crude metal from waste tin in methanesulfonic acid. The surface morphologies of electrodeposited tin on cathode were observed, the dendrite and delamination were inhibited by glycol group of organic additive. The impurity concentrations of tin crude metal and deposited metal were analyzed using ICP-OES. Quantitative analysis on casted tin crude metal showed that it consists of tin with 97.280 wt.% and several impurity metals of Ag, Cu, Pb, Ni, and etc. After tin electro-refining, the purity of tin increased up to 99.956 wt.%. Reduction current by cyclic voltammetry seems to be closely related to behavior of impurity in tin electro-refining.

Performance Improvement of Speaker Recognition Using Enhanced Feature Extraction in Glottal Flow Signals and Multiple Feature Parameter Combination (Glottal flow 신호에서의 향상된 특징추출 및 다중 특징파라미터 결합을 통한 화자인식 성능 향상)

  • Kang, Jihoon;Kim, Youngil;Jeong, Sangbae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.12
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    • pp.2792-2799
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    • 2015
  • In this paper, we utilize source mel-frequency cepstral coefficients (SMFCCs), skewness, and kurtosis extracted in glottal flow signals to improve speaker recognition performance. Generally, because the high band magnitude response of glottal flow signals is somewhat flat, the SMFCCs are extracted using the response below the predefined cutoff frequency. The extracted SMFCC, skewness, and kurtosis are concatenated with conventional feature parameters. Then, dimensional reduction by the principal component analysis (PCA) and the linear discriminat analysis (LDA) is followed to compare performances with conventional systems under equivalent conditions. The proposed recognition system outperformed the conventional system for large scale speaker recognition experiments. Especially, the performance improvement was more noticeable for small Gaussan mixtures.

Experimental Investigation for the Shroud Separation in the Supersonic Flow (초음속 비행환경 조건에서의 슈라우드 분리시험 연구)

  • Kim, Jung-Young;Lee, Dong-Min
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.7
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    • pp.539-549
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    • 2017
  • In this paper, experimental studies on the shroud separation were performed to investigate characteristics of the shroud separation at mach 3. Shroud separation tests were carried out in the vertical free-jet wind tunnel that is capable of testing separable structures. A shroud model was miniaturized to meet test objectives and test section dimensions of the wind tunnel. Pneumatic Locking and separation mechanisms were designed considering external force due to free stream. High speed cameras were used to record the shroud motion and unsteady shock patterns over the deploying shrouds during the shroud separation process. Also, unsteady pressures on the nose surface were measured by using the pressure sensors. Through the tests, the measurement data necessary for researches on the shroud separation technology were obtained. Shroud separation behaviors and characteristics of unsteady pressure on the nose surface for each external flow conditions were analyzed.

Comparison of several criteria for ordering independent components (독립성분의 순서화 방법 비교)

  • Choi, Eunbin;Cho, Sulim;Park, Mira
    • The Korean Journal of Applied Statistics
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    • v.30 no.6
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    • pp.889-899
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    • 2017
  • Independent component analysis is a multivariate approach to separate mixed signals into original signals. It is the most widely used method of blind source separation technique. ICA uses linear transformations such as principal component analysis and factor analysis, but differs in that ICA requires statistical independence and non-Gaussian assumptions of original signals. PCA have a natural ordering based on cumulative proportion of explained variance; howerver, ICA algorithms cannot identify the unique optimal ordering of the components. It is meaningful to set order because major components can be used for further analysis such as clustering and low-dimensional graphs. In this paper, we compare the performance of several criteria to determine the order of the components. Kurtosis, absolute value of kurtosis, negentropy, Kolmogorov-Smirnov statistic and sum of squared coefficients are considered. The criteria are evaluated by their ability to classify known groups. Two types of data are analyzed for illustration.

Change in the Physicochemical Properties of Doenjang Treated with Phosphate and Gas Absorber during Storage (인산염과 가스흡수제 첨가 된장의 저장 중 이화학적 변화)

  • Lee, Jung-Suck;Song, Kyung-Bin
    • Food Science and Preservation
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    • v.13 no.6
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    • pp.803-807
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    • 2006
  • Browning of commercial Doenjang product during storage and marketing is a main concern in the industry. There have been many studies on the improvement on the quality of Doenjang during storage. In this study, phosphate and gas absorber treatment was introduced in manufacturing of Doenjang to improve the color of commercial Doenjang during storage. Doenjang treated with Phosphate and 9as absorber (sample C). Doenjang teated with Phosphate only (sample B), and the control (sample A) were prepared and their physicochemical and sensory properties were determined during storage at $30^{\circ}C$ for 28 days. Sample C was the best in terms of color as well as sensory evaluation resulting in preventing browning of Doenjang during storage. These result suggest that commercial production of Doenjang should introduce phosphate and gas absorber treatment to improve the quality of Doenjang, and to prevent undesirable browning reaction during storage and marketing.