• Title/Summary/Keyword: 모델 이해

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PRECISE ORBIT PROPAGATION OF GEOSTATIONARY SATELLITE USING COWELL'S METHOD (코웰방법을 이용한 정지위성의 정밀궤도예측)

  • 윤재철;최규홍;김은규
    • Journal of Astronomy and Space Sciences
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    • v.14 no.1
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    • pp.136-141
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    • 1997
  • To calculate the position and velocity of the artificial satellite precisely, one has to build a mathematical model concerning the perturbations by understanding and analysing the space environment correctly and then quantifying. Due to these space environment model, the total acceleration of the artificial satellite can be expressed as the 2nd order differential equation and we build an orbit propagation algorithm by integrating twice this equation by using the Cowell's method which gives the position and velocity of the artificial satellite at any given time. Perturbations important for the orbits of geostationary spacecraft are the Earth's gravitational potential, the gravitational influences of the sun and moon, and the solar radiation pressure. For precise orbit propagation in Cowell' method, 40 x 40 spherical harmonic coefficients can be applied and the JPL DE403 ephemeris files were used to generate the range from earth to sun and moon and 8th order Runge-Kutta single step method with variable step-size control is used to integrate the the orbit propagation equations.

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Representation and Management of e-Learning Object Metadata Using ebXML (ebXML 등록저장소를 이용한 이러닝 객체 메타데이터의 표현과 관리)

  • Kim, Hyoung-Do
    • The Journal of the Korea Contents Association
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    • v.6 no.11
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    • pp.249-259
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    • 2006
  • E-learning objects should be appropriately described and classified using standard metadata for facilitating the processes of e-learning resource description, discovery and reuse. These metadata need to be published in a registry to reduce duplication of effort and enhance semantic interoperability. This paper describes how standard ebXML registries can be used for annotating, storing, discovering and retrieving e-learning object metadata. For semantic annotation of e-learning objects, IEEE LOM is adopted as the metadata ontology. In order to support the e-learning metadata ontology in interoperable ebXML registries, a mapping scheme between LOM and ebXML information model is proposed. The usefulness of standard ebXML registries for sharing e-learning metadata is demonstrated by prototyping an e-learning registry called ebRR4LOM based on the scheme.

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Chloroplast Genetic Transformation in Higher Plants: An Encounter Between Prokaryote and Eukaryote (고등식물의 엽록체 형질전환: 원핵생물과 진맥생물의 조우)

  • Chung, Hwa-Jee;Suh, Young-Bae;Jeong, Won-Joong;Min, Sung-Ran;Liu, Jang-R.
    • Journal of Plant Biotechnology
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    • v.33 no.3
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    • pp.185-194
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    • 2006
  • Chloroplasts are believed to be descended from certain cyanobacteria, which were taken up by phagocytosis into a host cell and lived there in a symbiotic relationship. In contrast to the current static concept on the chloroplast genome, its dynamism has been recently demonstrated: the chloroplast genome is active in intramolecular homolgous recombination, producing subgenomic circles when it obtains homolgous sequences via genetic transformation. Chloroplast tranformation in higher plants provides many advantages over nuclear transformation that include higher expression levels of transgenes, polycistronic expression of transgenes, and maternal transmission of transgenes. Tobacco has been used as a model for chloroplast genetic transformation. However, it is recently possible to transform the chloroplasts of other major food and economic crops including rice, soybean, and cotton. Chloroplast-transformed crops will be able to replace bioreactors using microorganisms for production of value-added proteins in future.

Advances in Plant Metabolomics (식물 대사체 연구의 진보)

  • Kim, Suk-Won;Chung, Hoe-Il;Liu, Jang-R.
    • Journal of Plant Biotechnology
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    • v.33 no.3
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    • pp.161-169
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    • 2006
  • Plant metabolomics is a plant biology field for identifying all of the metabolites found in a certain plant cell, tissue, organ, or whole plant in a given time and conditions and for studying changes in metabolic profiling as time goes or conditions change. Metabolomics is one of the most recently developed omics for holistic approach to biology and is a kind of systems biology. For holistic approach, metabolomics frequently uses chemometrics or multivariate statistical analysis of metabolic profillings. In plant biology, metabolomics is useful to determine functions of genes often in combination with DHA microarrays by analyzing tagged mutants of the model plants Arabidopsis and rice. This review paper attempted to introduce basic concepts of metabolomics and practical uses of multivariate statistical analysis of metabolic profiling obtained by $^1$H HMR and Fourier transform infrared spectrometry.

The Imperatives of Institutional Framework and Collaboration Mechanism in Agriculure Modernization-The Case of Abim District, Uganda (농업현대화를 위한 제도적 공동협력 프레임워크구축에 대한 연구: 우간다 Abim지역의 사례를 중심으로)

  • Ochieng, Haggai Kennedy Otieno;Kim, Jun Yeup
    • Journal of the Economic Geographical Society of Korea
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    • v.19 no.2
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    • pp.313-329
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    • 2016
  • The paper shows that Uganda lacks an adequate institutional framework to achieve agriculture modernization. Based on constellation model, the paper proposes an effective way to promote agricultural development through policy and institutional partnerships at various levels of governance and action by various stakeholders in the sector. From this theoretical perspective, the paper raises salient research questions: Why is Abim District an important focus for Agricultural development? What is the effect of institutional arrangements and partnerships in agriculture development in Abim District? What forms of institutional partnerships and collaboration framework can effectively address the challenge in the District and Northern Uganda as a whole? These concerns are important obstacles to improved agricultural performance in Uganda as dysfunctional institutional arrangements and norms are majorconstraints to agricultural development. The findings demonstrate that institutional gaps, bureaucracy, institutional proliferation and overlapping roles have derailed agriculture modernization. Hence, the development strategy proposes creating and rejuvenating all essential players operating in the region, developing or deepening their inter-linkages through judicious and sustainable partnerships with all the principal players in Abim District.

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Discussions About the Three Aspects of Scientific Literacy: Focus on Integrative Understanding, Settlement in Curriculum, and Civic Education (과학적 소양에 대한 세 가지 논의 -통합적 이해, 교육과정에의 정착, 시민교육을 중심으로-)

  • Park, Jongwon
    • Journal of The Korean Association For Science Education
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    • v.36 no.3
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    • pp.413-422
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    • 2016
  • There have been many discussions about scientific literacy (SL), which caused many science educators concern for many years. This paper focuses on three aspects about SL. First, there are various opinions, and components or types of SL. Second, it has been pointed out that the reconciliation between curriculum focusing on SL and curriculum focusing on scientific knowledge system is difficult. Third, the level of SL of citizens who learned science in schools is not so high. Related to these aspects, this paper suggests three recommendations. First, the paper suggests three dimensional model of SL and some examples of its application. Second, elementary and middle school focus on SL in their science curriculum and high school focuses on scientific knowledge system in the curriculum for preparing for future jobs. Third, we need to give efforts to lifelong science eduction for citizens' SL as well as school teachings for SL. In the conclusion section, it is described what aspects should be additionally considered for the discussions and recommendations about three aspects of SL.

Towards the Virtuous Circle in Virtual Community through Knowledge Seeking and Sharing (가상공동체의 지식선순환을 위한 지식탐색과 공유에 관한 연구)

  • Kim, Jae Kyung
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.19-38
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    • 2014
  • This study focused on the role of active knowledge seeking (knowledge browsing and knowledge searching) in the context of virtual community of interest. Knowledge seeking is rarely studied as an antecedent in knowledge management (KM) research. Active knowledge seeking is considered as antecedents of sense of virtual community which mediates to knowledge sharing intention and virtual community promotion. Research hypotheses are tested by applying structure equation modeling with survey data from virtual community members in South Korea. Active knowledge seeking behavior was found to be the strong predictor of sense of virtual community, which, in turn, positively affects knowledge sharing intention and virtual community promotion. Implication to practitioners is to understand and accommodate the members' knowledge seeking efforts, who are potential contributors and promoters of the virtual community. Knowledge seeking, knowledge sharing and promoting virtual community are more of human activities than technology and this study extends the understanding of such human activities. By providing a mechanism of how knowledge seeking and sharing could work harmoniously, a virtuous circle with win-win situation could be achieved in virtual communities.

A Preliminary Research on the Impact of Perception of Personal Information Leakage Incidents on the Behavior of Individual Information Management in the Mobile Banking Contexts (모바일 뱅킹 이용자의 개인정보 유출사고 인지가 개인정보관리 준수행동에 미치는 영향에 대한 사전 연구)

  • Kim, Jungduk;Lim, Se-Hun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.26 no.3
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    • pp.735-744
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    • 2016
  • Recently, personal information leakage incidents with increased usage of mobile services are increasing. Personal information leakage incidents can have a significant impact on an individual's mobile banking services. Accordingly, we examine relationships among individual's psychological characteristics, intention and behavior regarding compliance in an individual's perception on personal information leakage incidents in mobile banking contexts. In this study, for explaining our research model and understanding with personal psychology and behavior in mobile banking contexts, we adopted two theories, theory of interpersonal behavior and stimulus-response theory. We collected the 55 data using online surveyor and then analyzed structural equation model in order to find causal relationships among research variables. The results of this study should be useful to the mobile banking services companies in promoting service users to follow the information privacy policies.

A Study on Socio-Economic Effects of Italian Ports (이탈리아 항만의 사회경제학적 효과에 대한 연구)

  • D'agostini, Enrico;Ryoo, Dong-Keun
    • Journal of Navigation and Port Research
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    • v.41 no.4
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    • pp.243-250
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    • 2017
  • Seaports are not longer considered to be single entities for which the main activity is to load and discharge cargo, but rather as fundamental hubs within a complex supply chain serving global production networks. From a public perspective, they hold a key role in terms of their economic impact at the local, regional and national level by generating value added activity and employment. This issue is becoming increasingly pivotal for ports and their stakeholders. The objective of the study is to estimate a regression model of the value added activity and employment figures of 17 Italian ports for which there are no publications available. Concerning port system reform in Italy, the research intends to provide policy makers with a tool to measure the effects produced by ports and their importance to local communities and regions. The paper finds that in all Italian ports, the direct effects are larger than the indirect effects, and the bigger socio-economic effects are found in the biggest ports.

Study about Power Transformer Identification Method based on Power Line Communication Technology (전력선 통신 기법을 활용한 변압기 식별 방법에 대한 고찰)

  • Byun, Hee-Jung;Choi, Sang-jun;Shon, Sugoog
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.1006-1009
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    • 2015
  • Power-line communication technology is proposed to identify power transformers to serve customers in 3 phase -4 wires power distribution systems. Mathematical models for 3-phase power transformers, 3-phase wire lines, and customer loads are described to investigate the transmission characteristics of high frequency power line carrier. From the analysis, distribution line cable circuits have only a limited ability to carry higher frequencies. Typically power transformers in the distribution system prevent propagating the higher frequency carrier signal. The proposed method uses the limited propagation ability to identify the power transformer to serve customers. A novel power transformer identification system is designed and implemented. The system consists of a transmitter and a receiver with power-line communication module. Some experiments are conducted to verify the theoretical concepts in a big commercial building. Also some simulations are done to help and understand the concepts by using MATLAB Simulink simulator.

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