• Title/Summary/Keyword: momentum transfer

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Total Polyphenol Contents and Antioxidant Activities of Methanol Extracts from Vegetables produced in Ullung Island (울릉도산 산채류 추출물의 총 폴리페놀 함량 및 항산화 활성)

  • Lee, Syng-Ook;Lee, Hyo-Jung;Yu, Mi-Hee;Im, Hyo-Gwon;Lee, In-Seon
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.233-240
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    • 2005
  • To discover new functional materials using edible plants, antioxidant activities of methanol extracts from various parts of seven wild vegetables were investigated in vitro. Total polyphenol contents, determined by Folin-Denis method, varied from 16.74 to $130.22{\mu}g/mg$. Radical-scavenging activities of methanol extracts were examined using ${\alpha},\;{\alpha}-diphenyl-{\beta}-pirrylhydrazyl$ (DPPH) radicals and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assay. Inhibition effects on peroxidation of linoleic acid determined by ferric thiocyanate (FTC) method and on oxidative degradation of 2-deoxy-D-ribose in Fenton-type reaction system were dose-dependent. Athyrium acutipinulum Kodama (leaf and rood), Achyranthes japonica (Miq.) Nakai (seed), and Solidago virga-aurea var. gigantea Nakai (root) showed relatively high antioxidant activities in various systems.

Extraction Characteristics of Flavonoids from Lonicera flos by Supercritical Fluid Carbon Dioxide ($SF-CO_2$) with Co-solvent (초임계유체 $CO_2$ 및 Co-solvent 첨가에 따른 금은화(Lonicera fles)의 Flavonoid류 추출특성)

  • Suh, Sang-Chul;Cho, Sung-Gill;Hong, Joo-Heon;Choi, Yong-Hee
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.183-188
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    • 2005
  • Effects of co-solvent polarity, citric acid, pressure, temperature, run time, and co-solvent ratio on extraction of major flavonoids from Lonicera Flos were investigated using supercritical fluid $CO_{2}(SF-CO_{2})$. HPLC analysis revealed addition of pure methanol resulted in low extraction yield of major flavonoids, luteoloin (Lu), Quercetin (Qu), Apigenin (Ap). Under same condition, as co-solvent polarity increased, yields of major flavonoids increased gradually, At optimum co-solvent extraction condirion of 60% aqueous methanol (10%, v/v), yields of Lu, Qu, and Ap were 42.09, 28.18, and 3.49 mg/100 g, respectively. Addition of citric acid to 60% aqueous methanol gave higher, with addition of 1% citrie acid resulting in highest yields of 63.2 (Lu), 39.35 (Qu), and 5.79 (Ap) mg/100 g. Optimum extraction conditions of major flavonoids were 200 bar, $50^{\circ}C$, 60 min, and $CO_{2}$-methanol-water(20: 1.8: 1.2).

Classification of Estuaries based on Morphological Convergence (형태적 수렴 특성을 이용한 하구 분류)

  • SHIN, Hyun-jung;RHEW, Hosahng;LEE, Guan-hong
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.3
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    • pp.1-22
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    • 2012
  • The classification scheme of estuaries can be divided into two categories: qualitative classification based on geomorphic characteristics and quantitative classification based upon the physical properties of water body. While simple and intuitive scheme of the former is difficult to quantify, the latter is not easy to apply due to the lack of data. A classification scheme based on morphological convergence is very promising because it only requires easily accessible data such as width and depth of channels, as well as it can characterize estuaries in terms of tidal propagation. Thus, this paper examines the classification scheme based on estuarine morphological convergence using depth and width data obtained from 19 major Korean estuaries. Morphological convergence for each estuary was estimated with the estuarine length, width and depth data to get the convergence parameters, which includes the degree of funneling ${\nu}$ and the dimensionless estuarine length $y_0$. The transfer function ${\xi}({\nu},ky)$ is then deduced analytically from 1D depth-integrated hydrodynamic momentum equation and continuity equation for estuarine shapes. Tidal response of each estuary is finally calculated using ${\nu}$, $y_0$ and ${\xi}({\nu},ky)$ for comparison and classification. The 19 Korean estuaries were classified into three groups: tidal amplitude-dominated estuaries with standing wave-like tidal response (group 1), current-dominated estuaries with progressive wave-like tidal response (group 2), and the intermediate group (group 3) between groups 1 and 2. The sensitivity analysis revealed that uncertainties in determining the estuarine length can have a critical effect upon the results of classification, which indicates that the reasonable determination of the estuarine length is of critical importance. Once the estuarine length is feasibly determined, depth-convergence can be neglected without any negative effect on the classification scheme, which has an important ramification on the wide applicability of the classification scheme.

1970 UNESCO Convention on the Illicit Trafficking of Cultural Property and its Legal Implementations in the Republic of Korea (문화재 불법 거래 방지에 관한 1970년 유네스코 협약의 국내법적 이행 검토)

  • Kim, Jihon
    • Korean Journal of Heritage: History & Science
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    • v.53 no.4
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    • pp.274-291
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    • 2020
  • This year is the 50th anniversary of the adoption by UNESCO in 1970 of the Convention on the Means of Prohibiting and Preventing the Illicit Import, Export, and Transfer of Ownership of Cultural Property (the '1970 Convention'). Since its ratification of the 1970 Convention in 1983, the Republic of Korea has domestically implemented the Convention through its Cultural Heritage Protection Act, which was first enacted in 1962. This is a different form of implementation than is normally used for other UNESCO Conventions on cultural heritage, in that the Republic of Korea has recently adopted special acts to enforce the 2003 Convention for the Safeguarding of Intangible Cultural Heritage and the 1972 Convention concerning the Protection of the World Cultural and Natural Heritage. In addition, the 1970 Convention has been developed further through the introduction of new Operational Guidelines in 2015 for the concrete enforcement of the Convention, which has provided momentum for the Republic of Korea to analyze its current national legislation related to the 1970 Convention as well as consider its amendment in the future. Overall, the Cultural Heritage Protection Act of the Republic of Korea effectively reflects the duties of States Parties under the 1970 Convention. These include measures to introduce export certificates, prohibit the import of stolen cultural property, return other state parties' cultural property, and impose penalties or administrative sanctions in the event of any infringements. Indeed, the Republic of Korea's implementation of the 1970 Convention was introduced as an example of good practice at the Meeting of State Parties in 2019. However, changes in the illegal market for cultural property and development of relevant international law and measures imply that there still exists room for improvement concerning the legal implementation of the 1970 Convention at the national level. In particular, the Operational Guidelines recommend States Parties to adopt legal measures in two respects: detailed criteria for due diligence in assessing bona-fide purchasers, referring to the 1995 UNIDROIT Convention on Stolen or Illegally Exported Cultural Objects, and measures to address the emerging issue of illegal trade in cultural property on internet platforms. Amendment of the Cultural Heritage Protection Act and other relevant laws should be considered in order to duly reflect these issues. Taking that opportunity, concrete provisions to facilitate international cooperation in respect of the implementation of the 1970 Convention could be introduced as well. Such measures could be expected to strengthen the Republic of Korea's international legal cooperation to respond to the changing environment regarding illicit trafficking of cultural property and its restitution.

Application of Support Vector Regression for Improving the Performance of the Emotion Prediction Model (감정예측모형의 성과개선을 위한 Support Vector Regression 응용)

  • Kim, Seongjin;Ryoo, Eunchung;Jung, Min Kyu;Kim, Jae Kyeong;Ahn, Hyunchul
    • Journal of Intelligence and Information Systems
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    • v.18 no.3
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    • pp.185-202
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    • 2012
  • .Since the value of information has been realized in the information society, the usage and collection of information has become important. A facial expression that contains thousands of information as an artistic painting can be described in thousands of words. Followed by the idea, there has recently been a number of attempts to provide customers and companies with an intelligent service, which enables the perception of human emotions through one's facial expressions. For example, MIT Media Lab, the leading organization in this research area, has developed the human emotion prediction model, and has applied their studies to the commercial business. In the academic area, a number of the conventional methods such as Multiple Regression Analysis (MRA) or Artificial Neural Networks (ANN) have been applied to predict human emotion in prior studies. However, MRA is generally criticized because of its low prediction accuracy. This is inevitable since MRA can only explain the linear relationship between the dependent variables and the independent variable. To mitigate the limitations of MRA, some studies like Jung and Kim (2012) have used ANN as the alternative, and they reported that ANN generated more accurate prediction than the statistical methods like MRA. However, it has also been criticized due to over fitting and the difficulty of the network design (e.g. setting the number of the layers and the number of the nodes in the hidden layers). Under this background, we propose a novel model using Support Vector Regression (SVR) in order to increase the prediction accuracy. SVR is an extensive version of Support Vector Machine (SVM) designated to solve the regression problems. The model produced by SVR only depends on a subset of the training data, because the cost function for building the model ignores any training data that is close (within a threshold ${\varepsilon}$) to the model prediction. Using SVR, we tried to build a model that can measure the level of arousal and valence from the facial features. To validate the usefulness of the proposed model, we collected the data of facial reactions when providing appropriate visual stimulating contents, and extracted the features from the data. Next, the steps of the preprocessing were taken to choose statistically significant variables. In total, 297 cases were used for the experiment. As the comparative models, we also applied MRA and ANN to the same data set. For SVR, we adopted '${\varepsilon}$-insensitive loss function', and 'grid search' technique to find the optimal values of the parameters like C, d, ${\sigma}^2$, and ${\varepsilon}$. In the case of ANN, we adopted a standard three-layer backpropagation network, which has a single hidden layer. The learning rate and momentum rate of ANN were set to 10%, and we used sigmoid function as the transfer function of hidden and output nodes. We performed the experiments repeatedly by varying the number of nodes in the hidden layer to n/2, n, 3n/2, and 2n, where n is the number of the input variables. The stopping condition for ANN was set to 50,000 learning events. And, we used MAE (Mean Absolute Error) as the measure for performance comparison. From the experiment, we found that SVR achieved the highest prediction accuracy for the hold-out data set compared to MRA and ANN. Regardless of the target variables (the level of arousal, or the level of positive / negative valence), SVR showed the best performance for the hold-out data set. ANN also outperformed MRA, however, it showed the considerably lower prediction accuracy than SVR for both target variables. The findings of our research are expected to be useful to the researchers or practitioners who are willing to build the models for recognizing human emotions.