• Title/Summary/Keyword: Mass changes

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r-Learning and Educational Information Policies (r-Learning과 교육정보화 정책)

  • Lee, Jong-Yun
    • Journal of the Korea Convergence Society
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    • v.1 no.1
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    • pp.1-15
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    • 2010
  • The Education has responsibility for predicting the social changes and cultivating global talent which the society needs. The ministry of education, science and technology in govern ment has been the concerns on social educational changes and thus built the '5 31 educational reform policy' in 1995 by the educational reform committee. As a solution of a social change, this paper reviews the three-phase educational information policies, and e-learning and u-learning which are the main technologies in educational information. Also, the technologies of e-learning can be divided into m-learning, t-learning, u-learning, r-learning, game-based learning according to the contents mass media. Among them, this paper introduces the concept of robot-learning, called r-learning, and compares it with u-learning.

Wobbling galaxy spin axes in dense environments

  • Lee, Jaehyun;Kim, Suk;Jeong, Hyunjin;Smith, Rory;Choi, Hoseung;Lee, Youngdae;Joo, Seok-Joo;Kim, Hak-Sub;Yi, Sukyoung K.
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.46.3-46.3
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    • 2017
  • We investigate the changes of galaxy spin orientation in dense environments using hydrodynamical cosmological zoom-in simulations for 17 galaxy clusters. This study reveals that the spin axes of satellite galaxies become more unstable when the satellites have lower initial $V/{\sigma}$, orbits with smaller pericenter distance, and higher merger rates after infall into the model clusters. The satellite galaxies involved in mergers after infall experience twice larger angular changes of spin axes than those without mergers. We also find that perturbation exerted by environments or neighboring galaxies strongly correlates with the stability of spin orientation and final $V/{\sigma}$. On the other hand, the size or stellar mass density of the satellites are not significantly affected by mergers or perturbation in cluster environments.

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A Study on The Relational Database Adoption (관계형 데이타 베이스 채택에 관한 연구)

  • 김윤기;이재범;양경훈
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.10a
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    • pp.78-88
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    • 1996
  • It is important to understand the process of IT diffusion between organizations for meeting effectively IT progress and its changes. The previous studies provide, the process of IT diffusion between organizational members, organizational factors facilitating the assimilation of IT within the organization, and the organizational members' usage of communication channels in the IT adoption process. But they failed to provide comprehensively the diffusion process of IT between organizations. Therefore, an empirical research through a field survey has been performed to examine the diffusion process of RDB with 64 companies to overcome the limits of the previous studies. The purpose of this study is (1) to empirically examine the interaction of companies(prior adopters and potential adopters), (2) to look into the differences of the factors of organizational structure and the periods of RDB adoption process between OAE(Organizations Adopting Earlier) and OAL(Organizations Adopting Later), and the importance of communication channels used in IT planning stage and adoption stage, (3) to inquire into the difference of RDB performance between OAE and OAL. The results of this study indicate that there is no interaction between the prior adopters and the potential adopters. Also, there are great significant differences with regards to variables of CEO's age, CEO's concern on IT, formalization, centralization compensation systems, CIO's attitudes on changes, RDB adoption periods, performance of RDB. In addition, interpersonal channels have been much more used than mass communication channels in both IT planning stage and adoption stage. This study provides good guidelines to the companies and the vendors in shaping the strategies of IT adoption and IT diffusion respectively.

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Endophilin A2: A Potential Link to Adiposity and Beyond

  • Alfadda, Assim A.;Sallam, Reem M.;Gul, Rukhsana;Hwang, Injae;Ka, Sojeong
    • Molecules and Cells
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    • v.40 no.11
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    • pp.855-863
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    • 2017
  • Adipose tissue plays a central role in regulating dynamic cross-talk between tissues and organs. A detailed description of molecules that are differentially expressed upon changes in adipose tissue mass is expected to increase our understanding of the molecular mechanisms that underlie obesity and related metabolic co-morbidities. Our previous studies suggest a possible link between endophilins (SH3Grb2 proteins) and changes in body weight. To explore this further, we sought to assess the distribution of endophilin A2 (EA2) in human adipose tissue and experimental animals. Human paired adipose tissue samples (subcutaneous and visceral) were collected from subjects undergoing elective abdominal surgery and abdominal liposuction. We observed elevated EA2 gene expression in the subcutaneous compared to that in the visceral human adipose tissue. EA2 gene expression negatively correlated with adiponectin and chemerin in visceral adipose tissue, and positively correlated with $TNF-{\alpha}$ in subcutaneous adipose tissue. EA2 gene expression was significantly downregulated during differentiation of preadipocytes in vitro. In conclusion, this study provides a description of EA2 distribution and emphasizes a need to study the roles of this protein during the progression of obesity.

A Study on Fuzzy Control Simulator of Naturally Circulated Boiler (자연 순환식보일러의 퍼지제어 모사기 개발에 관한 연구)

  • Kim, Kwang-Sun;Kim, Sam-Un
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.4
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    • pp.543-554
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    • 2000
  • The engineering equations, which have been used in many engineering companies, were employed for the dynamic modelling part in order to develop the naturally circulated boiler simulator. The fuzzy algorithm, which is similar to the algorithm of making decision by the human being, was developed for the boiler simulator controller and its simulated variables were compared with those of classical PID simulations to verify the stability and the effectiveness of fuzzy controller. The simulator is for the naturally circulated boiler and the main components are the furnace, the drum, the super heater, and the economizer. The combustion and thermal radiation dominant equations were used within the furnace and the mass conservation and the energy rate balance equations were employed for the drum part. The heat transfer rates were calculated using the logarithmic mean temperature differences both for the super heater and for the economizer. The simulations are very useful to understand the boiler operations and the engineering design of the main components. The main program was developed under the PC window condition by linking the fuzzy controller to the main boiler program using the Visual C++ language. The various operational conditions such as the abrupt changes of load, the changes of water supply pipes and the diameter of drum were simulated.

Prediction of Changed Design Parameter of Proportional Damping Structure by Using Modified Dynamic Characteristics (동특성 변화를 이용하여 비례감쇠 구조물의 변경된 설계파라미터 예측)

  • Lee, Jung-Youn
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.7
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    • pp.873-879
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    • 2010
  • It is common to predict structural dynamic design parameters due to the change of design parameter, but to predict the amount of changed design parameter where the mass and stiffness are being modified are rarely found in previous literature. In this study, the changed design parameter in a proportional damping system is predicted by using sensitivity coefficients and an iterative method. The sensitivity coefficients are determined from the changes in eigenvectors; these changes are due to modification. This method is applied to a three-story shear structure. To validate the prediction of the changed design parameter, the results are compared to the reanalysis results; both results are in good agreement.

Changes of Flavor Components in Chewing Gum during Storage by Gas Chromatography/Mass Spectrometry (GC/MS에 의한 저장중 츄잉껌 향기성분 변화연구)

  • Shin, Seong-Kee;Kim, Sang-Ho;Lee, Yoon-Hyung;Rhee, Kyu-Soon
    • Korean Journal of Food Science and Technology
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    • v.24 no.1
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    • pp.25-28
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    • 1992
  • The changes of amount in flavor components of chewing gum during storage of various relative humidity were studied by GC/MS. The volatile components in chewing gum were extracted by sample preperation and 15 volatile components were identified by NIST/NBS library searching. According to the period of storage, quantities of major volatile components extracted by tetrahydrofuran-methanol solutions were determined by using tetradecane as internal standard. Until 4 weeks, comparing with starting peak area ratio, the decrease of chewing gum flavor components were rapid at 33, 75 than 53 R.H(%). And after 16 weeks, amount of chewing gum flavor at all storage conditions similarly decreased to $45{\sim}49%$ of the initial amount.

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Experimental investigation of the large amplitude vibrations of a thin-walled column under self-weight

  • Goncalves, Paulo B.;Jurjo, Daniel Leonardo B.R.;Magluta, Carlos;Roitman, Ney
    • Structural Engineering and Mechanics
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    • v.46 no.6
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    • pp.869-886
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    • 2013
  • This work presents an experimental methodology specially developed for the nonlinear large-amplitude free vibration analysis of a clamped-free thin-walled metal column under self-weight. The main contribution of this paper is related to the developed experimental methodology which is based on a remote sensing technique using a computer vision system that integrates, on-line, the digital image acquisition and its treatment through special image processing routines. The main importance of this methodology is that it performs large deflections measurements without making contact with the structure and thus, not introducing undesirable changes in its behavior, for instance, appreciable changes in mass and stiffness properties. This structure presents, in most cases, highly non-linear responses, which cannot be reproduced by conventional finite-element softwares due, mainly, to the simultaneous influence of geometric and inertial non-linearities. To capture the non-linearities associated with large amplitude vibration and be able to describe the buckling process, the structure is discretized as a sequence of jointed coupled elastic pendulums. The obtained numerical results are favorably compared with the experimental ones, in the pre- and post-buckling regimes.

Numerical Studies of Subsidence and Hydraulic Conductivity Enhancement Due to Underground excavation (지하 굴착에 의한 침하와 수리전도도 증가에 관한 수치해석적 연구)

  • Yoon, Yong-Kyun
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 2000.09a
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    • pp.139-146
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    • 2000
  • This study investigates the changes of subsidence and hydraulic conductivity by underground mining. Coupling between post-mining induced strains and strain-dependent hydraulic conductivities is obtained by idealizing a jointed rock mass as an equivalent porous medium in which the hydraulic conductivity of a single joint is defined through parallel plate description. Results indicate that post-mining hydraulic conductivities are directly related to the strain field occurred by subsidence induced deformation. Maximum subsidence and hydraulic conductivity values increase as a panel width does widen. Joint spacing has an effect on the intensity of the changes in hydraulic conductivity.

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Numerical Studies of Subsidence and Hydraulic Conductivity Enhancement Due to Underground Excavation (지하 굴착에 의한 침하와 수리전도도 증가에 관한 수치해석적 연구)

  • 윤용균
    • Tunnel and Underground Space
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    • v.10 no.3
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    • pp.387-394
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    • 2000
  • This is study investigates the changes of subsidence and hydraulic conductivity by underground mining Coupling between post-mining induced strains and strain-dependent hydraulic conductivities is obtained by idealizing a jointed rock mass as an equivalent porous medium in which the hydraulic conductivity of a single joint is defined through parallel plate description. Results indicate that post-mining hydraulic conductivities are directly related to the strain field occurred by subsidence induced deformation. Maximum subsidence and hydraulic conductivity values increase as a panel width does widen. Joint spacing has an effect on the intensity of the changes in hydraulic conductivity.

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