• Title/Summary/Keyword: Field Theory

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Computing the Refined Compression Field Theory

  • Hernandez-Diaz, A.M.;Garcia-Roman, M.D.
    • International Journal of Concrete Structures and Materials
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    • v.10 no.2
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    • pp.143-147
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    • 2016
  • In recent years, some modifications were introduced in the stress-strain relationship of the steel in order to develop a more efficient shear model for reinforced concrete members. The last contribution in this sense corresponding to the Refined Compression Field Theory (RCFT, 2009); this theory proposed a steel constitutive model that has account the tension stiffening area prescribed by technical codes, what simplifies all the design process. However, under certain design conditions supported by such codes, the RCFT model does not provide a real (non-complex) solution for the steel yield strain when the prescribed tension stiffening area is considered; then the load-strain response cannot be computed. In this technical note, the tension stiffening area is fixed in order to guarantee the application of the embedded steel constitutive model for all the standard design range.

Reproducing kernel based evaluation of incompatibility tensor in field theory of plasticity

  • Aoyagi, Y.;Hasebe, T.;Guan, P.C.;Chen, J.S.
    • Interaction and multiscale mechanics
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    • v.1 no.4
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    • pp.423-435
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    • 2008
  • This paper employs the reproducing kernel (RK) approximation for evaluation of field theory-based incompatibility tensor in a polycrystalline plasticity simulation. The modulation patterns, which is interpreted as mimicking geometrical-type dislocation substructures, are obtained based on the proposed method. Comparisons are made using FEM and RK based approximation methods among different support sizes and other evaluation conditions of the strain gradients. It is demonstrated that the evolution of the modulation patterns needs to be accurately calculated at each time step to yield a correct physical interpretation. The effect of the higher order strain derivative processing zone on the predicted modulation patterns is also discussed.

On the ring of integers of cyclotomic function fields

  • Bae, Sunghan;Hahn, Sang-Geun
    • Bulletin of the Korean Mathematical Society
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    • v.29 no.1
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    • pp.153-163
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    • 1992
  • Carlitz module is used to study abelian extensions of K=$F_{q}$(T). In number theory every abelian etension of Q is contained in a cyclotomic field. Similarly every abelian extension of $F_{q}$(T) with some condition on .inf. is contained in a cyclotomic function field. Hence the study of cyclotomic function fields in analogy with cyclotomic fields is an important subject in number theory. Much are known in this direction such as ring of integers, class groups and units ([G], [G-R]). In this article we are concerned with the ring of integers in a cyclotomic function field. In [G], it is shown that the ring of integers is generated by a primitive root of the Carlitz module using the ramification theory and localization. Here we will give another proof, which is rather elementary and explicit, of this fact following the methods in [W].[W].

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MFSC: Mean-Field-Theory and Spreading-Coefficient Based Degree Distribution Analysis in Social Network

  • Lin, Chongze;Zheng, Yi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.8
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    • pp.3630-3656
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    • 2018
  • Degree distribution can provide basic information for structural characteristics and internal relationship in social network. It is a critical procedure for social network topology analysis. In this paper, based on the mean-field theory, we study a special type of social network with exponential distribution of time intervals. First of all, in order to improve the accuracy of analysis, we propose a spreading coefficient algorithm based on intimate relationship, which determines the number of the joined members through the intimacy among members. Then, simulation show that the degree distribution of follows the power-law distribution and has small-world characteristics. Finally, we compare the performance of our algorithm with the existing algorithms, and find that our algorithm improves the accuracy of degree distribution as well as reducing the time complexity significantly, which can complete 29.04% higher precision and 40.94% lower implementation time.

A study on the magnetic flux distribution of 3-phase 4-pole induction motor by finite element method (유한요소법에 의한 삼상유도전동기의 자속분포해석에 관한 연구)

  • 임달호;현동석;임태빈
    • 전기의세계
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    • v.30 no.4
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    • pp.219-226
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    • 1981
  • The magnetic field distribution in saturable iron part of electromagnetic energy conversion divices is defined by the nonlinear quasi-Poisson enquation that is described the electromagnetic field characteristics and satisfied the natural boundary condition. The solution of this equation is obtained by minimizing an energy functional by means of trial function that defined in triangular subregion of two-dimensional field region. As a result, the accuracy of the machine design is increased by use of its solution. In this respect, this study is developed the basic theory to analyze the magnetic flux distribution in saturable iron part and air gap of induction motor that its secondary part is short circuit by the variational principle, the minimized theory of energy functional, the application of F.E.M., and treatment of computer. As theoritical data compared with the practics, the validity of the theory in this study is supported by experimental findings.

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On scale-dependent stability analysis of functionally graded magneto-electro-thermo-elastic cylindrical nanoshells

  • Asrari, Reza;Ebrahimi, Farzad;Kheirikhah, Mohammad Mahdi
    • Structural Engineering and Mechanics
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    • v.75 no.6
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    • pp.659-674
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    • 2020
  • The present paper employs nonlocal strain gradient theory (NSGT) to study buckling behavior of functionally graded magneto-electro-thermo-elastic (FG-METE) nanoshells under various physical fields. NSGT modeling of the nanoshell contains two size parameters, one related to nonlocal stress field and another related to strain gradients. It is considered that mechanical, thermal, electrical and magnetic loads are exerted to the nanoshell. Temperature field has uniform and linear variation in nanoshell thickness. According to a power-law function, piezo-magnetic, thermal and mechanical properties of the nanoshell are considered to be graded in thickness direction. Five coupled governing equations have been obtained by using Hamilton's principle and then solved implementing Galerkin's method. Influences of temperature field, electric voltage, magnetic potential, nonlocality, strain gradient parameter and FG material exponent on buckling loads of the FG-METE nanoshell have been studied in detail.

Implementation of the modified compression field theory in a tangent stiffness-based finite element formulation

  • Aquino, Wilkins;Erdem, Ibrahim
    • Steel and Composite Structures
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    • v.7 no.4
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    • pp.263-278
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    • 2007
  • A finite element implementation of the modified compression field theory (MCFT) using a tangential formulation is presented in this work. Previous work reported on implementations of MCFT has concentrated mainly on secant formulations. This work describes details of the implementation of a modular algorithmic structure of a reinforced concrete constitutive model in nonlinear finite element schemes that use a Jacobian matrix in the solution of the nonlinear system of algebraic equations. The implementation was verified and validated using experimental and analytical data reported in the literature. The developed algorithm, which converges accurately and quickly, can be easily implemented in any finite element code.

Game Theoretic Modeling for Mobile Malicious Node Detection Problem in Static Wireless Sensor Networks

  • Ho, Jun-Won
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.238-242
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    • 2021
  • Game theory has been regarded as a useful theoretical tool for modeling the interactions between distinct entities and thus it has been harnessed in various research field. In particular, research attention has been shown to how to apply game theory to modeling the interactions between malign and benign entities in the field of wireless networks. Although various game theoretic modeling work have been proposed in the field of wireless networks, our proposed work is disparate to the existing work in the sense that we focus on mobile malign node detection problem in static wireless sensor networks. More specifically, we propose a Bayesian game theoretic modeling for mobile malign node detection problem in static wireless sensor networks. In our modeling, we formulate a two-player static Bayesian game with imperfect information such that player 1 is aware of the type of player 2, but player 2 is not aware of the type of player 1. We use four strategies in our static Bayesian game. We obtain Bayesian Nash Equilibria with pure strategies under certain conditions.

A study on the improvement of the local stress field in a displacement-formulated finite element solution (변위형 유한요소 해에서 국부응력장 향상에 대한 연구)

  • Song, Kee-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.2
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    • pp.278-288
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    • 1998
  • An efficient and useful method to improve the local stress field in a displacement-formulated finite element solution has been proposed using the theory of conjugate approximations for a stress field and the Loubignac's iterative method for a displacement field. Validity of the proposed method has been tested through three test examples, to improve the stress field and displacement field in the whole domain and the local regions. As a result of analysis on the test examples, it is found that the stress field in the local regions are approximated to those in the whole domain within a few iterations which have satisfied the original finite element equilibrium equation. In addition, it is found that the local stress field are by far better approximated to the exact stress field than the displacement-based stress field with the reduction of the finite-element mesh-size.

Traditional Embroidery in India based on Bourdieu's Cultural Theory (부르디외 문화이론으로 살펴본 인도 지역별 전통자수)

  • Kim, Yi Rang;Kwon, Mi Jeong
    • Fashion & Textile Research Journal
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    • v.23 no.6
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    • pp.758-769
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    • 2021
  • The purpose of this study is to analyze the traditional embroidery in India by region based on Bourdieu's cultural theory. As the research methods for this study, literature and case studies were conducted. The results of the study are summarized as follows. First, India's regions could be divided into four distinct regions based on language and religion. The main concepts of Bourdieu's cultural theory, namely the sub-dimensions of field and habitus, were the field of social system, the field of goods & economy, the field of environment/region, culture, and ethnicity. Second, Eastern India's embroidery was influenced by Hinduism and traditional art. The embroidery used various fabrics such as the Applique work, and vivid colors and patterns were mainly used in the Hindu myths, animals, and flower patterns of the embroidery. Third, embroidery in Western India was influenced by exotic cultures like Persian due to geographical conditions, and embroidery via the use of gold threads and various ornaments was developed. Symbolized flower patterns and geometric patterns were used a lot in the respective embroidery. Fourth, embroidery in southern India was influenced by the Dravidian culture and their architectural style, which saw the emergence of an embroidery that used simple colored cross-stitch. Most of the patterns in this embroidery are geometricized. Fifth, Northern Indian embroidery has historically served as the center of power, resulting in an embroidery that uses various forms and materials. In this embroidery, flower patterns are mainly used. Finally, the characteristics of the traditional embroidery of India's each region is based on Bourdieu's cultural theory, which could be summarized as ethnic religiosity, exotic splendor, structural formality, and symbolic power.