• Title/Summary/Keyword: Multi-Scale Structure

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Magneto-electro-elastic vibration analysis of modified couple stress-based three-layered micro rectangular plates exposed to multi-physical fields considering the flexoelectricity effects

  • Khorasani, Mohammad;Eyvazian, Arameh;Karbon, Mohammed;Tounsi, Abdelouahed;Lampani, Luca;Sebaey, Tamer A.
    • Smart Structures and Systems
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    • v.26 no.3
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    • pp.331-343
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    • 2020
  • In this paper, based on the CPT, motion equations for a sandwich plate containing a core and two integrated face-sheets have derived. The structure rests on the Visco-Pasternak foundation, which includes normal and shear modules. The piezo-magnetic core is made of CoFe2O4 and also is subjected to 3D magnetic potential. Two face sheets at top and bottom of the core are under electrical fields. Also, in order to obtain more accuracy, the effect of flexoelectricity has took into account at face sheets' relations in this work. Flexoelectricity is a property of all insulators whereby they polarize when subject to an inhomogeneous deformation. This property plays a crucial role in small-scale rather than macro scale. Employing CPT, Hamilton's principle, flexoelectricity considerations, the governing equations are derived and then solved analytically. By present work a detailed numerical study is obtained based on Piezoelectricity, Flexoelectricity and modified couple stress theories to indicate the significant effect of length scale parameter, shear correction factor, aspect and thickness ratios and boundary conditions on natural frequency of sandwich plates. Also, the figures show that there is an excellent agreement between present study and previous researches. These finding can be used for automotive industries, aircrafts, marine vessels and building industries.

A Study on the Competitive Strategy of Department Store for Sustainable Development (지속가능한 성장을 위한 백화점의 경쟁전략에 관한 연구)

  • Jin, Chang-Beom;Park, Chul-Ju;Youn, Myoung-Kil
    • Journal of Distribution Science
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    • v.15 no.3
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    • pp.73-80
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    • 2017
  • Purpose - Since Korean distribution market was opened, the domestic environment in department stores has been changed by the pattern of consumption and consumer need based on income classes. As multilateral Free Trade Agreement (FTA) accelerates opening markets, the scale of circulating capital has become bigger. Large-scale commercial facilities have developed quickly as a form of a large shopping center, thus, the matter of choice and securing market area became an important valuable in this trend. Moreover, multi-complex space has been proposed as the goal of successful business with promoting the public benefit. Research design, data, and methodology - This research studied consumer behavior using data about the life style and sales of consumers, not statistical data or survey as previous studies. This research tried to find the differentiation in complex cultural space with consumption behavior of department store. Results - As the structure of society and culture was getting diverse and complex, economic growth and development with such diversity and complexity improved consumers' quality of life. The changes of consumer life style are quite natural like human instinct. Department stores have activated retail business with the products of accumulated technology. Moreover, they have created the space of consumption and culture. Because of these social and environmental changes, department stores are being developed as Multi-functional spaces as well as sale places considering the strategies of department and the changes of consumers' purchasing behaviors. Conclusions - Urban culture complex is a landmark standing for the culture era of 21st century. It has provided an opportunity for consumers to enjoy culture, and has been an important factor to improve company images. Based on these roles and needs, expectancy effects are related with consumer preference and space preference, and the attitude toward companies. Moreover, the expectancy effects from those relationships are getting bigger and bigger. We should respect nature, a characteristic of Korean architecture, maintain visual continuity that harmonies with nature in the development of the complex space of the domestic department stores, and should take significance in the development of the complex cultural space in the direction of feeling the hierarchy of the space to obtain the visual pleasure with the artificial structure.

Life Satisfaction Scale for Elderly : Revisited (구조적 차원성 탐색을 통한 '노인 생활 만족도 척도'의 재발견: 최성재의 '노인 생활 만족도 척도'를 중심으로)

  • Choi, Hye-Ji;Lee, Young-Boon
    • Korean Journal of Social Welfare
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    • v.58 no.3
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    • pp.27-49
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    • 2006
  • The purpose of the present study was to investigate dimensionality and psychometric properties of identified theoretical constructs of the 'Life Satisfaction Scale for Elderly(LSSE)', which was developed by Choi, Sung-Jae in 1986. Data was obtained from 'The survey of health and welfare status of the elderly aged 65 or older in Chung-Choo city'. The subjects were 275 elderly. Results showed that LSSE had a multi-dimensional structure with three theoretical constructs. Each theoretical construct was named as 'positive affect and subjective satisfaction', 'negative self image and affect', and 'self-value'. Three theoretical constructs had high levels of reliability and validity based on internal construct. 'Positive affect and subjective satisfaction' and 'negative self image and affect' showed high levels of convergent and discriminant validity. 'Self-value' had a high level of convergent validity but acceptable level of discriminant validity. Results of this study revealed that there was a difference in theoretical dimensionality of LSSE between this study and Choi's study, which explained the dimensionality of LSSE as a single dimension. However, the result of this study regarding theoretical dimensionality supported findings from existing studies which insisted that life satisfaction had a multi-dimensional structure.

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Application of Effective Regularization to Gradient-based Seismic Full Waveform Inversion using Selective Smoothing Coefficients (선택적 평활화 계수를 이용한 그래디언트기반 탄성파 완전파형역산의 효과적인 정규화 기법 적용)

  • Park, Yunhui;Pyun, Sukjoon
    • Geophysics and Geophysical Exploration
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    • v.16 no.4
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    • pp.211-216
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    • 2013
  • In general, smoothing filters regularize functions by reducing differences between adjacent values. The smoothing filters, therefore, can regularize inverse solutions and produce more accurate subsurface structure when we apply it to full waveform inversion. If we apply a smoothing filter with a constant coefficient to subsurface image or velocity model, it will make layer interfaces and fault structures vague because it does not consider any information of geologic structures and variations of velocity. In this study, we develop a selective smoothing regularization technique, which adapts smoothing coefficients according to inversion iteration, to solve the weakness of smoothing regularization with a constant coefficient. First, we determine appropriate frequencies and analyze the corresponding wavenumber coverage. Then, we define effective maximum wavenumber as 99 percentile of wavenumber spectrum in order to choose smoothing coefficients which can effectively limit the wavenumber coverage. By adapting the chosen smoothing coefficients according to the iteration, we can implement multi-scale full waveform inversion while inverting multi-frequency components simultaneously. Through the successful inversion example on a salt model with high-contrast velocity structures, we can note that our method effectively regularizes the inverse solution. We also verify that our scheme is applicable to field data through the numerical example to the synthetic data containing random noise.

Application of Seismic Analysis and Design Method on the Bridges by Spectral Analysis Method (스펙트럼해석법에 의한 교량의 지진해석 및 설계방법의 적용)

  • 김운학;유영화;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.2
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    • pp.17-29
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    • 1997
  • Single-mode spectral analysis method is usually applied to a small-scale bridges with the simple geometric shape and uses only fundamental period to estimate the elastic earthquake forces and the displacements of the substructure. On the other hand, multi-mode spectral analysis method may be used instead if the possibilities of potential damage are developed when considering significance, scale, and geometric shape of briages. Since the dynamic responses of bridge can be significantly different depending on the modeling techniques for the restraint and support conditions etc, it may be misled to the unexpected results. In this study the dynamic analysis program which can model and analyze the bridge as a two- or three-dimensional framed structure is developed and verified with the results of other reliable program. Using this program together with the post processor, the designer can easily and readily obtain the reponses(moments, base shears, and displacements)of bridges necessary to design purpose. And further from the analysis results according to the variations of type, scale, and restraint and supprot conditions of bridges including sectional properties, applications of the effective and desirable seismic design are presented.

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Multi-scale Analysis of Thin film Considering Surface Effects (표면효과를 고려한 박막구조의 멀티스케일 해석)

  • Cho, Maeng-Hyo;Choi, Jin-Bok;Jung, Kwang-Sub
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.3
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    • pp.287-292
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    • 2007
  • In general, the response of bulk material is independent of its size when it comes to considering classical elasticity theory. Because the surface to bulk ratio of the large solids is very small, the influence of surface can be negligible. But the surface effect plays important role as the surface to bulk ratio becomes larger, that is, the contribution of the surface effect must be considered in nano-size elements such as thin film or beam structure. Molecular dynamics computation has been a conventional way to analyze these ultra-thin structures but this method is limited to simulate on the order of $10^6{\sim}10^9$ atoms for a few nanoseconds, and besides, very time consuming. Analysis of structures in submicro to micro range(thin-film, wire etc.) is difficult with classical molecular dynamics due to the restriction of computing resources and time. Therefore, in this paper, the continuum-based method is considered to simulate the overall physical and mechanical properties of the structures in nano-scale, especially, for the thin-film.

Application of Artificial Neural Network to Improve Quantitative Precipitation Forecasts of Meso-scale Numerical Weather Prediction (중규모수치예보자료의 정량적 강수추정량 개선을 위한 인공신경망기법)

  • Kang, Boo-Sik;Lee, Bong-Ki
    • Journal of Korea Water Resources Association
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    • v.44 no.2
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    • pp.97-107
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    • 2011
  • For the purpose of enhancing usability of NWP (Numerical Weather Prediction), the quantitative precipitation prediction scheme was suggested. In this research, precipitation by leading time was predicted using 3-hour rainfall accumulation by meso-scale numerical weather model and AWS (Automatic Weather Station), precipitation water and relative humidity observed by atmospheric sounding station, probability of rainfall occurrence by leading time in June and July, 2001 and August, 2002. Considering the nonlinear process of ranfall producing mechanism, the ANN (Artificial Neural Network) that is useful in nonlinear fitting between rainfall and the other atmospheric variables. The feedforward multi-layer perceptron was used for neural network structure, and the nonlinear bipolaractivation function was used for neural network training for converting negative rainfall into no rain value. The ANN simulated rainfall was validated by leading time using Nash-Sutcliffe Coefficient of Efficiency (COE) and Coefficient of Correlation (CORR). As a result, the 3 hour rainfall accumulation basis shows that the COE of the areal mean of the Korean peninsula was improved from -0.04 to 0.31 for the 12 hr leading time, -0.04 to 0.38 for the 24 hr leading time, -0.03 to 0.33 for the 36 hr leading time, and -0.05 to 0.27 for the 48 hr leading time.

Improvement of crossflow model of MULTID component in MARS-KS with inter-channel mixing model for enhancing analysis performance in rod bundle

  • Yunseok Lee;Taewan Kim
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4357-4366
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    • 2023
  • MARS-KS, a domestic regulatory confirmatory code of Republic of Korea, had been developed by integrating RELAP5/MOD2 and COBRA-TF. The integration of COBRA-TF allowed to extend the capability of MARS-KS, limited to one-dimensional analysis, to multi-dimensional analysis. The use of COBRA-TF was mainly focused on subchannel analyses for simulating multi-dimensional behavior within the reactor core. However, this feature has been remained as a legacy without ongoing maintenance. Meanwhile, MARS-KS also includes its own multidimensional component, namely MULTID, which is also feasible to simulate three-dimensional convection and diffusion. The MULTID is capable of modeling the turbulent diffusion using simple mixing length model. The implementation of the turbulent mixing is of importance for analyzing the reactor core where a disturbing cross-sectional structure of rod bundle makes the flow perturbation and corresponding mixing stronger. In addition, the presence of this turbulent behavior allows the secondary transports with net mass exchange between subchannels. However, a series of assessments performed in previous studies revealed that the turbulence model of the MULTID could not simulate the aforementioned effective mixing occurred in the subchannel-scale problems. This is obvious consequence since the physical models of the MULTID neglect the effect of mass transport and thereby, it cannot model the void drift effect and resulting phasic distribution within a bundle. Thus, in this study, the turbulence mixing model of the MULTID has been improved by means of the inter-channel mixing model, widely utilized in subchannel analysis, in order to extend the application of the MULTID to small-scale problems. A series of assessments has been performed against rod bundle experiments, namely GE 3X3 and PSBT, to evaluate the performance of the introduced mixing model. The assessment results revealed that the application of the inter-channel mixing model allowed to enhance the prediction of the MULTID in subchannel scale problems. In addition, it was indicated that the code could not predict appropriate phasic distribution in the rod bundle without the model. Considering that the proper prediction of the phasic distribution is important when considering pin-based and/or assembly-based expressions of the reactor core, the results of this study clearly indicate that the inter-channel mixing model is required for analyzing the rod bundle, appropriately.

Visualization research based on hero tale stories in a fantasy movie (영웅서사구조 중심으로 하는 판타지영화의 시각화 연구)

  • Han, Myung-Hee
    • Journal of Digital Contents Society
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    • v.11 no.2
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    • pp.185-194
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    • 2010
  • The digital contents industry already heads toward the OSMU(One Source Multi Use) method of media. In case the success of the original novel recreates to a movie, the success of a movie is again noticed with the original novel. For this reason, a novel and movie are open at the same time, In this paper, we analyze through the case study of three fantasy films having the narrative structure of the germane myth : The Lord of The Rings, Harry Potter, The Chronicles Of Narnia based on the analysis basis : Hero's Journey 12 steps by J. Campbell, The analysis of scenes of each film visualizing the narrative structure of a novel can be used as the basic materials in the process of visualizing the scale of the original and message of a writer, we consequently believe that these analysis will be able to be applied the appropriate visual techniques (the special effect, the scene tractions, and etc.)in visualization of films.

The Visualization of films for the stand on narrative of Germanic Mythology -Focused on "The Road of the Ring", "Harry Potter", and "The Chronicles Of Narnia"- (게르만신화의 서사구조를 바탕으로 한 영화의 시각화 -반지의 제왕, 해리포터, 나니아 연대기를 중심으로-)

  • Baek, Kwang-Ho;Han, Myung-Hee;Kim, Mi-Jin
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.1129-1136
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    • 2009
  • The digital contents industry already heads toward the OSMU(One Source Multi Use) method of media. In case the success of the original novel recreates to a movie, the success of a movie is again noticed with the original novel. For this reason, a novel and movie are open at the same time, In this paper, we analyze through the case study of three fantasy films having the narrative structure of the germane myth : The Lord of The Rings, Harry Potter, The Chronicles Of Narnia based on the analysis basis : Hero's Journey 12 steps by J. Campbell, The analysis of scenes of each film visualizing the narrative structure of a novel can be used as the basic materials in the process of visualizing the scale of the original and message of a writer, we consequently believe that these analysis will be able to be applied the appropriate visual techniques (the special effect, the scene tractions, and etc.)in visualization of films.

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