• Title/Summary/Keyword: a diffusion model

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Analysis of Relationship between Functional Areas and Individual Competencies of Extension Workers (농촌지도사의 직무영역과 개별역량의 관계분석)

  • Kim, Hyo Mi;Kim, Ji Hyun;Kim, Sa Gyun;Kim, Yoon Doo
    • Journal of Agricultural Extension & Community Development
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    • v.20 no.2
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    • pp.383-405
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    • 2013
  • The purpose of this study is trying to drive the competence relevant to extension worker's functions. We also conducted a correspondence analysis between the individual competence and extension worker's functions. As a result of the analysis, the functions of guidance planning correlated with 'problem solving' and 'creation of ideas'. Education functions correlated with 'extension work evaluation', 'customer satisfaction' and 'understanding'. And crop technology diffusion functions were analyzed relevant to the ability of 'training skill' and 'responsibility' is high. In this study, extension empowerment need to educate suitable education which is high relation between competency and extension worker's functions and develop new suitable education model. And the baseline data will be made use, when arrange reasonable function to new extension workers, through individual competency measured.

A Study on the Infrastructure of All-electric Houses in the Viewpoint of Hydrogen Economy (수소경제 관점의 전기에너지주택 보급기반 구축에 관한 연구)

  • Hwang, Sung-Wook;Lee, Hyeon-Ju;Kim, Kang-Sik;Nah, Hwan-Seon;Kim, Jung-Hoon
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.1
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    • pp.100-109
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    • 2012
  • In this paper, some ideas are proposed to establish the infrastructure of all-electric houses which are able to reduce primary energy consumption and $CO_2$ emission by adopting heat pump systems and induction heating cookers excluding the use of fossil fuel energy. This electrification concept is based on the consumption of only one type of energy which means electricity as secondary energy and the conventional fossil fuel energy is just consumed to generate electricity as primary energy. All-electric house is laid on the extension of the hydrogen economy in a long-term viewpoint so that the effectiveness of this new conceptual house is estimated analyzing the reduction of $CO_2$ emission. In this analysis, the balance of electricity supply and demand is considered including the construction of new power plants by renewable energy such as nuclear, IGCC and fuel cell because decarbonization is an essential element of hydrogen technology and economy and this action is accomplished in both supply and demand side of electricity. The results are able to contribute to develop various useful hydrogen policies and strategies and some detail researches are required previously to make the best application of this new conceptual house.

A Study on the Optimal Resource Configuration Considering Load Characteristics of Electric Vehicles in Micro Grid Environment (전기자동차 부하 특성을 고려한 마이크로그리드의 최적 전원 구성에 관한 연구)

  • Hwang, Sung-Wook;Chae, Woo-Kyu;Lee, Hak-Ju;Yun, Sang-Yun;Kim, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.2
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    • pp.228-231
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    • 2015
  • In power system research fields, one of current key issues is the construction and commercialization of micro grid site which is called green island, carbon zero island, energy independent island, building micro grid, etc. and various affiliated technologies have been being vigorously developed to realize. In addition, various researches about electric vehicles (EVs) are in progress and it is expected to penetrate rapidly with the next a few years. Some new load models should be developed integrating with electric vehicle loads because the EVs' deployment could cause the change of load composition rate on power system planning and operations. EVs are also resources for micro grid as well as distributed generation and demand response so that various supply and demand side resources should be considered for micro grid researches. In this paper, the load composition rate of residential sectors is prospected considering the deployment of EVs and the resource configuration of micro grid is optimized based on net present cost. In the optimization, the load patten of case studies includes EV's charging characteristics and various cases are simulated comparing micro grid environment and normal condition. HOMER is used to compare various cases and economic effects.

Prediction of Carbonation Progress for Concrete Structures Considering Change of Atmospheric Environment (대기환경변화를 고려한 콘크리트 구조물의 중성화 예측)

  • Lee, Chang-Soo;Yoon, In-Seok
    • Journal of the Korea Concrete Institute
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    • v.15 no.4
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    • pp.574-584
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    • 2003
  • The most common deterioration cause of concrete structures in urban environment is carbonation. Recently, the $CO_2$ concentration and temperature at atmosphere is sharply increased with time due to global warming phenomena. In this study, the climate scenario IS92a, which was suggested by the IPCC, is used to consider temperature and atmospheric $CO_2$ concentration change in the model of service life prediction. The modified mathematical solution, which was based on the Fick's 1st law of diffusion, was used to reflect concrete materials properties such as the degree of hydration of concrete with elapsed time, and important parameters, which associated with deterioration rate. The techniques of service life prediction are developed introducing the method of reliability and stochastic concept to consider microclimatic condition in Seoul, South Korea. From the result of service life prediction, concrete containing high W/C ratio is shown fast carbonation rate due to $CO_2$ concentration increase. It is concluded that the deterioration of concrete structures due to carbonation is insignificant problem on the conditions that below W/C 55%, well curing concrete.

Continuous dialysis of selected salts of sulphuric acid

  • Bendova, Helena;Snejdrla, Pavel;Palaty, Zdenek
    • Membrane and Water Treatment
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    • v.1 no.3
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    • pp.171-179
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    • 2010
  • The transport of selected salts of sulphuric acid (cobalt, copper, iron(II), manganese, nickel and zinc sulphate) through an anion-exchange membrane Neosepta-AFN was investigated in a counter-current continuous dialyzer at various salt concentrations and volumetric liquid flow rates. The basic transport characteristics - the rejection coefficient of salt and the permeability of the membrane - were calculated from measurements at steady state. The salt concentration in model mixtures was changed in the limits from 0.1 to 1.0 kmol $m^{-3}$ and the volumetric liquid flow rate of the inlet streams was in the limits from $8{\times}10^{-9}$ to $24{\times}10^{-9}m^3\;s^{-1}$. Under the experimental conditions given, the rejection coefficient of salts tested was in the range from 65% to 94%. The lowest values were obtained for iron(II) sulphate, while the highest for copper sulphate. The maximum rejection of salt was reached at the highest volumetric liquid flow rate and the highest salt concentration in the feed. The permeability ($P_A$) of the Neosepta-AFN membrane for the individual salts was in the range from $0.49{\times}10^{-7}m\;s^{-1}$ to $1.8{\times}10^{-7}m\;s^{-1}$ and it can be described by the following series: $P_{FeSO_4}$ < $P_{NiSO_4}$ < $P_{ZnSO_4}$ < $P_{CoSO_4}$ < $P_{MnSO_4}$ < $P_{CuSO_4}$. The permeability of the membrane was strongly affected by the salt concentration in the feed - it decreased with an increasing salt concentration.

Innovation and Intangible Capital for Economic Growth (혁신과 무형자본을 통한 경제성장)

  • Kim, Nari
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.454-464
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    • 2018
  • The OECD estimates that a high concentration of intangible capital is in the richest countries of the world. Studies show that intangibles have a positive relation with economic growth. However, different types of intangibles can have different impacts on economic performance. Therefore, this paper attempts to distinguish the differences within the intangibles in influencing economic growth by analyzing three different characteristics of the intangibles. Three main types of intangibles (computerized information, innovative property and economic competencies) are analyzed based on the degree of tacitness, the process of creation and diffusion, and the level of embedded value-added. This research uses Polanyi's classification of tacitness of knowledge, the Nonaka-Takeuchi Model and the "smiling curve" to find that not only investing more in intangible capital but also developing more "tacit" type of intangibles are important for economic growth.

Numerical Analysis of the Particle Dispersion by the Variation of the Velocity Ratio in a Mixing Layer (혼합층에서 속도비 변화에 따른 입자확산 유동해석)

  • Seo, Tae Won;Kim, Tae Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.3
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    • pp.8-14
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    • 2003
  • The particle dispersion in the turbulent mixing layer has been numerically investigated to clarify the effect of the velocity ratio in the large-scale vortical structures. In this study the LES with subgrid-scale model is employed. The Lagrangian method to predict the particle motion is applied. The particles of 10, 50, 150, 200${\mu}m$ in mean diameter were loaded into the origin of the mixing layer. It is shown that the characteristics of flow and growth rate are strongly dependent on the variation of the velocity ratio. It is also shown the relationship between the Stokes number and the particle dispersion. As a result, in the case of St~1 the particle dispersion is faster than the diffustion of the flow field while in the cases of both St<<1 and St>>1 it is shown that the particle dispersion in lower than the diffusion of the flow filed.

Pervaporative Recovery of Bio-butanol through Dense- and Composite-type PDMS Membranes (PDMS막을 이용한 바이오 부탄올 분리정제와 투과증발 특성에 관한 연구)

  • Kim, Jeong-Hoon;Ryu, Bi-Ho;Chang, Bong-Jun;Kim, Woo-Nyon
    • Membrane Journal
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    • v.19 no.2
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    • pp.157-164
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    • 2009
  • Bio-butanol recovery by pervaporation was performed with dense and composite polydimethylsiloxane (PDMS) membranes. The pervaporative behavior of the membranes was investigated as a function of operation temperature $(20{\sim}40^{\circ}C)$ and membrane thickness $(100{\sim}1{\mu}m)$ using a series of aqueous BtOH model solutions $(1{\sim}5wt%)$. With the increment of the BtOH concentration in feed, the Butanol concentration in permeate, pervaporation selectivity of Butanol over water and Butanol permeation flux increased. As the operating temperature of feed solutions increased, the BtOH concentration in permeate, pervaporation selectivity and permeation flux increased markedly. As the thickness of the PDMS membrane decreased, permeation flux increased but pervaporation selectivity decreased. These results were explained in terms of high solubility and low diffusion resistance of BtOH over water toward hydrophobic and rubbery PDMS membranes.

Influential Factors on the Adoption of Performance Infants' Wear -Focusing on Product Attributes, Consumer Traits, and Communication Characteristics- (혁신제품으로서의 기능성 소재 유아복의 채택 단계에 미치는 영향 요인 -제품 특성, 소비자 특성, 커뮤니케이션 특성을 중심으로-)

  • Hong Kyung-Hee;Lee Yoon-Jung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.1 s.149
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    • pp.146-156
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    • 2006
  • The purpose of this study is to investigate the factors that influence consumers' adoption of performance infants' wear made of functional textiles. Based on Innovation Diffusion Model, product attributes, consumer traits, and communication characteristics were considered. A survey was carried out with a convenience sample of 241 housewives who have infants under 4 year-old, living in the Seoul metropolitan area. To analyze the data, SPSS 10.0 was used employing ANOVA, Duncan's post-hoc comparison, $X^2$, and f-test. The participants were classified into 4 groups based on their levels of adoption of performance infants' wear: No-Cognition, Negative Attitude, Positive Attitude, and Purchasing groups. There were significant differences among the four groups in terms of their perception of product attributes, communication characteristics, and personal traits. In terms of product attributes, the Positive Attitude group and Purchasing group showed higher perception of relative advantage, compatibility, trialability and observability than other groups. These groups were also high in terms of their tendency of actively seeking for additional product information, and particularly relied on the information from experts on TV or the Internet, personal experience posted on the Internet, or their own experience. Those who were in professional, well-educated and high income brackets were more likely to be Purchasing group than Positive Attitude group, which means once the positive attitude was formed they are likely to purchase the product.

Intention to Use and Group Difference in Adopting Big Data: Towards a Comprehensive View (활용 주체별 빅데이터 수용 인식 차이에 관한 연구: 활용 목적, 조직 규모, 업종 특성을 중심으로)

  • Lee, Young-Joo;Yang, Hyun-Cheol
    • Informatization Policy
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    • v.24 no.1
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    • pp.79-99
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    • 2017
  • Despite the early success story, the pan-industry diffusion of big data has been slow mostly due to lack of confidence of the value creation and privacy-related concerns. The problem leads us to the need to a stakeholder analysis on the adoption process of big data. The present study combines technology acceptance model, task-technology fit theory, and privacy calculus theory to integrate the positive and negative factors on the big data adoption. The empirical analysis was performed based on the survey from the current and potential big data users. Results revealed perceived usefulness, task-technology fit, and privacy concern are significant antecedents to the intention to use big data. Furthermore, there are significant differences in the perceptions of each constructs among groups divided by the types of big data use, with several exceptions. And the control effect was found in the magnitude of the relation between independent variables and dependent variable. The theoretical and politic implications of the analysis are discussed as to the promotion of big data industry.