• Title/Summary/Keyword: a diffusion model

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THE LORENTZ FORCE IN ATMOSPHERES OF CP STARS: θ AUR

  • VALYAVIN G.;KOCHUKHOV O.;SHULYAK D.;LEE B.-C.;GALAZUTDINOV G.;KIM K.-M.;HAN I.
    • Journal of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.283-287
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    • 2005
  • The slow evolution of global magnetic fields and other dynamical processes in atmospheres of CP magnetic stars lead to the development of induced electric currents in all conductive atmospheric layers. The Lorentz force, which results from the interaction between a magnetic field and the induced currents, may modify the atmospheric structure and provide insight into the formation and evolution of stellar magnetic fields. This modification of the pressure-temperature structure influences the formation of absorption spectral features producing characteristic rotational variability of some spectral lines, especially the Balmer lines (Valyavin et al., 2004 and references therein). In order to study these theoretical predictions we began systematic spectroscopic survey of Balmer line variability in spectra of brightest CP magnetic stars. Here we present the first results of the program. A0p star $\Theta$ Aur revealed significant variability of the Balmer profiles during the star's rotation. Character of this variablity corresponds to that classified by Kroll (1989) as a result of an impact of significant Lorentz force. From the obtained data we estimate that amplitudes of the variation at H$\alpha$, H$\beta$, H$\gamma$ and H$\delta$ profiles reach up to $2.4\%$during full rotation cycle of the star. Using computation of our model atmospheres (Valyavin et al., 2004) we interpret these data within the framework of the simplest model of the evolution of global magnetic fields in chemically peculiar stars. Assuming that the field is represented by a dipole, we estimate the characteristic e.m.f. induced by the field decay electric current (and the Lorentz force as the result) on the order of $E {\~} 10^{-11}$ cgs units, which may indicate very fast (< < $10^{10}$ years) evolution rate of the field. This result strongly contradicts the theoretical point of view that global stellar magnetic fields of CP stars are fossil and their the characteristic decay time of about $10^{10}$ yr. Alternatively, we briefly discuss concurring effects (like the ambipolar diffusion) which may also lead to significant atmospheric currents producing the observable Lorentz force.

Electromagnetic Traveltime Tomography with Wavefield Transformation (파동장 변환을 이용한 전자탐사 주시 토모그래피)

  • Lee, Tae-Jong;Suh, Jung-Hee;Shin, Chang-Soo
    • Geophysics and Geophysical Exploration
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    • v.2 no.1
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    • pp.17-25
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    • 1999
  • A traveltime tomography has been carried out by transforming electromagnetic data in frequency domain to wave-like domain. The transform uniquely relates a field satisfying a diffusion equation to an integral of the corresponding wavefield. But direct transform of frequency domain magnetic fields to wave-field domain is ill-posed problem because the kernel of the integral transform is highly damped. In this study, instead of solving such an unstable problem, it is assumed that wave-fields in transformed domain can be approximated by sum of ray series. And for further simplicity, reflection and refraction energy compared to that of direct wave is weak enough to be neglected. Then first arrival can be approximated by calculating the traveltime of direct wave only. But these assumptions are valid when the conductivity contrast between background medium and the target anomalous body is low enough. So this approach can only be applied to the models with low conductivity contrast. To verify the algorithm, traveltime calculated by this approach was compared to that of direct transform method and exact traveltime, calculated analytically, for homogeneous whole space. The error in first arrival picked by this study was less than that of direct transformation method, especially when the number of frequency samples is less than 10, or when the data are noisy. Layered earth model with varying conductivity contrasts and inclined dyke model have been successfully imaged by applying nonlinear traveltime tomography in 30 iterations within three CPU minutes on a IBM Pentium Pro 200 MHz.

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Knowledge Production Function in South Korea : An Empirical Analysis (우리나라 지식생산함수 : 실증분석)

  • Cho, Sang-Sup;Jung, Dong-Jin
    • Journal of Korea Technology Innovation Society
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    • v.10 no.3
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    • pp.383-405
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    • 2007
  • In this paper we estimate knowledge production function for 15 South Korean industry sectors using panel data. To accommodate the influence of inter-sectoral interactions on the creation of knowledge, we estimate parameters for related knowledge production functions using the Dynamic Seemingly Unrelated Regression(DSUR) model proposed by Mark et al. (2005). We find the elasticity of knowledge production with respect to the size of research staff to be 0.25 and that with respect to the existing stock of knowledge to be 0.35. The fact that the elasticity of new knowledge creation with regard to the existing knowledge stock is below 1 in South Korea corroborates the view that the rate of long-term growth of her economy is chiefly determined by the elasticity related to production functions of goods and services and the rate of population growth, and that her government policy, to ensure a continued growth for the Korean economy, must shift the focus of R&D policies from the current direct intervention-centered model to one consisting of indirect measures, namely supporting knowledge management and diffusion and the creation of a knowledge sharing system. In terms of R&D policy implications it could be consider that the national knowledge production system should strengthen the cumulative process of knowledge accumulation and population for research and development. Our country R&D policy, also, need to adopt a global approach to increase knowledge stock at the highest levels of a country.

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The Development of Gangnam and the Formation of Gangnam-style Urbanism : On the Spatial Selectivity of the Anti-Communist Authoritarian Developmental State (강남 개발과 강남적 도시성의 형성 - 반공 권위주의 발전국가의 공간선택성을 중심으로 -)

  • Ji, Joo-Hyoung
    • Journal of the Korean association of regional geographers
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    • v.22 no.2
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    • pp.307-330
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    • 2016
  • This article aims to explain how Gangnam, as a model and standard of compressed urbanization in South Korea, was created. Gangnam and Gangnam-style urbanization need attention not only because they contrast with Korea's urbanization in the past as well as urbanization in the West but also they provide an important model in contemporary Korea's politics, economy and culture. However, there are little studies of how Gangnam's peculiar urbanism was created. To fill this gap, this article will first capture Gangnam's peculiar urbanism as a material landscape and sociocultural lifestyle. Gangnam-style urbanism is (a) materially characterized by high-rise apartment complexes owned by the middle and upper class for dwelling and asset growth and (b) socio-culturally characterized by political conservatism, public indifference, competition over academic performance, appearance, and fashion, and nightlife. Then it will show Gangnam's archetype was created in a spatially and temporally compressed way in and through the spatial selectivity of Korean anti-communist authoritarian developmental state strategies: (1) anti-communism led to the diffusion and accommodation of the population through apartments in Gangnam in the context of its confrontation with North Korea and the fast-growing population of Seoul; (2) military authoritarianism excluded the low-income class and the urban poor from urban development; and (3) the developmental state adopted selective housing policy which treated construction companies and the middle class preferentially through exceptional zoning and price distortions, promoting the construction of apartment in Gangnam and its resultant uneven development.

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Recombinant Production and Antimicrobial Activity of an Antimicrobial Model Peptide (Uu-ilys-CF) Derived from Spoon Worm Lysozyme, Uu-ilys (개불 라이소자임 유래 항균성 모델 펩타이드(Uu-ilys-CF)의 재조합 단백질 생산 및 항균 활성)

  • Oh, Hye Young;Go, Hye-Jin;Park, Nam Gyu
    • Journal of Life Science
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    • v.31 no.1
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    • pp.83-89
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    • 2021
  • Uu-ilys, an i-type lysozyme from spoon worm (Urechis unicinctus), is an innate immune factor that plays an important role in the defense against pathogens. It also possesses non-enzymatic antibacterial activity. Thus, there is a possibility to develop an antimicrobial model peptide from Uu-ilys. In this study, we report the design, production, and antibacterial activity of an Uu-ilys analog that exhibits antibacterial activity. The Uu-ilys structure was fragmented according to its secondary structures to predict the regions with antimicrobial activity using antimicrobial peptide (AMP) prediction tools from different AMP databases. A peptide containing the C-terminal fragment was predicted to exert antimicrobial activity. The chosen fragment was designated as an Uu-ilys analog containing the C-terminal fragment, Uu-ilys-CF. To examine the possibility of developing an AMP using the sequence of Uu-ilys-CF, recombinant fusion protein (TrxA-Uu-ilys-CF) was produced in an expression system that was heterologous. The produced fusion protein was cleaved after methionine leaving Uu-ilys-CF free from the fusion protein. This was then isolated through high performance liquid chromatography and reverse phase column, CapCell-Pak C18. The antibacterial activity of Uu-ilys-CF against different microbial strains (four gram-positive, six gram-negative, and one fungal strain) were assessed through the ultrasensitive radial diffusion assay (URDA). Among the bacterial strains tested, Salmonella enterica was the most susceptible. While the fungal strain tested was not susceptible to Uu-ilys-CF, broad spectrum antibacterial activity was observed.

Growth of Globalization Cultural Spread and Technological Innovation Study with Anti-Globalization (세계화의 문화 확산과 반세계화에 따른 기술혁신 성장연구)

  • Seo, Dae-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.3
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    • pp.769-777
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    • 2023
  • Globalization has brought about rapid economic, technological, and cultural changes. In order for countries around the world to communicate, recognize and understand globalization, creativity or planning ability can be used to code. In this paper, we would like to present and prove a data analysis that can solve world problems. In the global market, the value of goods or services increases with connectivity. This connection is becoming one of the factors that increase the value of culture. Changes taking this into account promoted cultural spread and innovative growth, and increased productivity and competitiveness in each region of the world. This paper compares the income of the middle class in the United States on the impact of globalization and anti-globalization on cultural spread and innovative growth. Globalization has created an environment in which various elements of K-culture can interact and spread. Through the Internet, social media, and international travel, globalization has had a positive impact on Korea's innovative growth. In areas such as economic activity, technological innovation, and creative industries, globalization has facilitated new tech and approaches, Through this, it changed the existing economic model and contributed to exports K-culture with a new middle class model. However, globalization in the cultural industry can result in the loss of regional characteristics & individuality, which can lead to the middle class cultural unification and alienation(chasm). As a result of the empirical analysis of K-exports for the middle income in the United States, cultural diffusion and innovation must be developed even in anti-globalization. With these industrial changes the soft power value of the Korean Wave proves that it can create value for use for the middle class of major exporting countries.

An Exploratory Study on Forecasting Sales Take-off Timing for Products in Multiple Markets (해외 복수 시장 진출 기업의 제품 매출 이륙 시점 예측 모형에 관한 연구)

  • Chung, Jaihak;Chung, Hokyung
    • Asia Marketing Journal
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    • v.10 no.2
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    • pp.1-29
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    • 2008
  • The objective of our study is to provide an exploratory model for forecasting sales take-off timing of a product in the context of multi-national markets. We evaluated the usefulness of key predictors such as multiple market information, product attributes, price, and sales for the forecasting of sales take-off timing by applying the suggested model to monthly sales data for PDP and LCD TV provided by a Korean electronics manufacturer. We have found some important results for global companies from the empirical analysis. Firstly, innovation coefficients obtained from sales data of a particular product in other markets can provide the most useful information on sales take-off timing of the product in a target market. However, imitation coefficients obtained from the sales data of a particular product in the target market and other markets are not useful for sales take-off timing of the product in the target market. Secondly, price and product attributes significantly influence on take-off timing. It is noteworthy that the ratio of the price of the target product to the average price of the market is more important than the price ofthe target product itself. Lastly, the cumulative sales of the product are still useful for the prediction of sales take-off timing. Our model outperformed the average model in terms of hit-rate.

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A Study on Public Interest-based Technology Valuation Models in Water Resources Field (수자원 분야 공익형 기술가치평가 시스템에 대한 연구)

  • Ryu, Seung-Mi;Sung, Tae-Eung
    • Journal of Intelligence and Information Systems
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    • v.24 no.3
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    • pp.177-198
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    • 2018
  • Recently, as economic property it has become necessary to acquire and utilize the framework for water resource measurement and performance management as the property of water resources changes to hold "public property". To date, the evaluation of water technology has been carried out by feasibility study analysis or technology assessment based on net present value (NPV) or benefit-to-cost (B/C) effect, however it is not yet systemized in terms of valuation models to objectively assess an economic value of technology-based business to receive diffusion and feedback of research outcomes. Therefore, K-water (known as a government-supported public company in Korea) company feels the necessity to establish a technology valuation framework suitable for technical characteristics of water resources fields in charge and verify an exemplified case applied to the technology. The K-water evaluation technology applied to this study, as a public interest goods, can be used as a tool to measure the value and achievement contributed to society and to manage them. Therefore, by calculating the value in which the subject technology contributed to the entire society as a public resource, we make use of it as a basis information for the advertising medium of performance on the influence effect of the benefits or the necessity of cost input, and then secure the legitimacy for large-scale R&D cost input in terms of the characteristics of public technology. Hence, K-water company, one of the public corporation in Korea which deals with public goods of 'water resources', will be able to establish a commercialization strategy for business operation and prepare for a basis for the performance calculation of input R&D cost. In this study, K-water has developed a web-based technology valuation model for public interest type water resources based on the technology evaluation system that is suitable for the characteristics of a technology in water resources fields. In particular, by utilizing the evaluation methodology of the Institute of Advanced Industrial Science and Technology (AIST) in Japan to match the expense items to the expense accounts based on the related benefit items, we proposed the so-called 'K-water's proprietary model' which involves the 'cost-benefit' approach and the FCF (Free Cash Flow), and ultimately led to build a pipeline on the K-water research performance management system and then verify the practical case of a technology related to "desalination". We analyze the embedded design logic and evaluation process of web-based valuation system that reflects characteristics of water resources technology, reference information and database(D/B)-associated logic for each model to calculate public interest-based and profit-based technology values in technology integrated management system. We review the hybrid evaluation module that reflects the quantitative index of the qualitative evaluation indices reflecting the unique characteristics of water resources and the visualized user-interface (UI) of the actual web-based evaluation, which both are appended for calculating the business value based on financial data to the existing web-based technology valuation systems in other fields. K-water's technology valuation model is evaluated by distinguishing between public-interest type and profitable-type water technology. First, evaluation modules in profit-type technology valuation model are designed based on 'profitability of technology'. For example, the technology inventory K-water holds has a number of profit-oriented technologies such as water treatment membranes. On the other hand, the public interest-type technology valuation is designed to evaluate the public-interest oriented technology such as the dam, which reflects the characteristics of public benefits and costs. In order to examine the appropriateness of the cost-benefit based public utility valuation model (i.e. K-water specific technology valuation model) presented in this study, we applied to practical cases from calculation of benefit-to-cost analysis on water resource technology with 20 years of lifetime. In future we will additionally conduct verifying the K-water public utility-based valuation model by each business model which reflects various business environmental characteristics.

The Change in Geotechnical Properties of the Deposited Clay Contaminated by Leachate from Waste Disposals (침출수로 오염된 퇴적점토의 역학적 특성변화)

  • Ha, Kwang-Hyun;Lee, Sang-Eun
    • Journal of the Korean GEO-environmental Society
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    • v.7 no.3
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    • pp.43-54
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    • 2006
  • In this paper, the uniaxial, triaxial compression tests and consolidation tests on the clay sample substituted initial pore water for pollutant were performed to evaluate the change in geotechnical properties of the contaminated clay. The contaminant transport analysis on embankment type landfill using the MT3D model was also performed to evaluate the extent of transport and diffusion. There was tendency that strength, compressibility and permeability has increased with the increase in the concentration of NaCl solution. The increase in the strength and compressibility of sample saturated with leachate was higher than samples saturated with NaCl solution, but in the permeability coefficient was lower. As the result of contaminant transport analysis, the predicted concentration was in high with the increase in the initial concentration of $Cl^-$ ion and increased in a non-linear form. The transportation distance calculated with use of regression equation between the distance from contaminant source and the concentration of $Cl^-$ ion was increased with the increase in the initial concentration.

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Anthocyanins from Clitoria ternatea Attenuate Food-Borne Penicillium expansum and its Potential Application as Food Biopreservative

  • Leong, Chean-Ring;Azizi, Muhammad Afif Kamarul;Taher, Md Abu;Wahidin, Suzana;Lee, Kok-Chang;Tan, Wen-Nee;Tong, Woei-Yenn
    • Natural Product Sciences
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    • v.23 no.2
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    • pp.125-131
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    • 2017
  • Clitoria ternatea or Commonly known blue pea, is a perennial climber crop native to Asian countries. The current study was aimed to evaluate the antimicrobial activity C. ternatea extract on food borne microorganisms and its antifungal effect on Penicillium expansum. The extract showed significant antimicrobial activity against 3 Gram positive bacteria, 2 Gram negative bacteria and 1 filamentous fungus on disc diffusion assay. The extract also showed good biocidal effect on all Gram positive bacteria tested and P. expansum. However, the kill curve analysis revealed that the fungicidal activity of the extract against P. expansum conidia was depend on the concentration of the extract and the time of exposure of the conidia to the extract. The scanning electron micrograph of the extract treated P. expansum culture showed alterations in the morphology of fungal hyphae. The germination of P. expansum conidia was completely inhibited and conidial development was totally suppressed by the extract, suggesting the possible mode of action of anthocyanin. Besides, the extract also exhibited 5.0-log suppression of microbial growth relative to control in the rice model. The results indicate the potential use of the C. ternatea anthocyanin as food biopreservative.