• Title/Summary/Keyword: Equivalence theory

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A Theoretical and Numerical Study on the Effects of Prereinforcement of Tunnel Face (터널막장 선행보강 효과에 관한 이론적.수치해석적 연구)

  • 김광진;문현구
    • Tunnel and Underground Space
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    • v.11 no.4
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    • pp.328-338
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    • 2001
  • Horizontal tunnel face reinforcement using Fiber Glass Tube(FGT) or steel pipe and pipe roofing techniques are frequently used when the stability of newly excavated tunnel is not guaranteed. However, the mechanical behavior of tunnels using these techniques has not been fully understood so far. Therefore, engineering rule of thumb is commonly applied during designing procedure, and it is difficult to adopt these techniques rationally. In this study, the application of a simplified numerical analysis method based on composite mechanics is verified. The mean field theory and the strain energy theory are used to obtain the equivalence elastic moduli of reinforced soil and rock. Furthermore, a parametric study on the deformational behavior of tunnel face is performed for various patterns of prereinforcement.

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POINTWISE CROSS-SECTION-BASED ON-THE-FLY RESONANCE INTERFERENCE TREATMENT WITH INTERMEDIATE RESONANCE APPROXIMATION

  • BACHA, MEER;JOO, HAN GYU
    • Nuclear Engineering and Technology
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    • v.47 no.7
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    • pp.791-803
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    • 2015
  • The effective cross sections (XSs) in the direct whole core calculation code nTRACER are evaluated by the equivalence theory-based resonance-integral-table method using the WIMS-based library as an alternative to the subgroup method. The background XSs, as well as the Dancoff correction factors, were evaluated by the enhanced neutron-current method. A method, with pointwise microscopic XSs on a union-lethargy grid, was used for the generation of resonance-interference factors (RIFs) for mixed resonant absorbers. This method was modified by the intermediate-resonance approximation by replacing the potential XSs for the non-absorbing moderator nuclides with the background XSs and neglecting the resonance-elastic scattering. The resonance-escape probability was implemented to incorporate the energy self-shielding effect in the spectrum. The XSs were improved using the proposed method as compared to the narrow resonance infinite massbased method. The RIFs were improved by 1% in $^{235}U$, 7% in $^{239}Pu$, and >2% in $^{240}Pu$. To account for thermal feedback, a new feature was incorporated with the interpolation of pre-generated RIFs at the multigroup level and the results compared with the conventional resonance-interference model. This method provided adequate results in terms of XSs and k-eff. The results were verified first by the comparison of RIFs with the exact RIFs, and then comparing the XSs with the McCARD calculations for the homogeneous configurations, with burned fuel containing a mixture of resonant nuclides at different burnups and temperatures. The RIFs and XSs for the mixture showed good agreement, which verified the accuracy of the RIF evaluation using the proposed method. The method was then verified by comparing the XSs for the virtual environment for reactor applicationbenchmark pin-cell problem, as well as the heterogeneous pin cell containing burned fuel with McCARD. The method works well for homogeneous, as well as heterogeneous configurations.

Translation of Separable Systems into the Lambda Calculus (분리 시스템의 람다 계산법으로의 변환)

  • Byun, Sug-Woo
    • Journal of KIISE:Computer Systems and Theory
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    • v.35 no.4
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    • pp.178-185
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    • 2008
  • This research presents an translation technique of encoding rewrite rules with patterns into the lambda calculus. We show, following the theory of Böhm separability, rewrite rules with distinctive patterns, called separable systems, can be translated into the lambda calculus. Moreover, according to the property of Böhm equivalence classes, we can also encode rewrite systems with default rules, which allows to interpret some of 'undefined' terms of TRSs as an identified lambda term.

3D material model for nonlinear basic creep of concrete

  • Bockhold, Jorg
    • Computers and Concrete
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    • v.4 no.2
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    • pp.101-117
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    • 2007
  • A new model predicting the nonlinear basic creep behaviour of concrete structures subjected to high multi-axial stresses is proposed. It combines a model based on the thermodynamic framework of the elasto-plastic continuum damage theory for time-independent material behaviour and a rheological model describing phenomenologically the long-term delayed deformation. Strength increase due to ageing is regarded. The general 3D solution for the creep theory is derived from a rate-type form of the uniaxial formulation by the assumption of associated creep flow and a theorem of energy equivalence. The model is able to reproduce linear primary creep as well as secondary and tertiary creep stages under high compressive stresses. For concrete in tension a simple viscoelastic formulation is applied. The material law is then incorporated into a finite element solution procedure for analysis of reinforced concrete structures. Numerical examples of uniaxial creep tests and concrete members show excellent agreement with experimental results.

Numerical Experiment for a Strain Energy Equivalence Principle (SEEP)-based Continuum Damage Model (탄성변형에너지 등가원리 기반 연속체 손상모델에 대한 수치실험)

  • Youn, Deok-Ki;Lee, U-Sik
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.31-34
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    • 2006
  • A new continuum damage theory (CDT) has been proposed by Lee et al. (1996) based on the SEEP. The CDT has the apparent advantage over the other related theories because the complete constitutive law can be readily derived by simply replacing the virgin elastic stiffness with the effective orthotropic elastic stiffness obtained by using the proposed continuum damage theory. In this paper, the CDT is evaluated by the numerical experiment comparing the mode shapes and natural frequencies of a square plate containing a small line-through crack with those of the same plate with a damaged site replaced with the effective orthotropic elastic stiffness computed by using the CDT.

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Algorithm for Efficient D-Class Computation (효율적인 D-클래스 계산을 위한 알고리즘)

  • Han, Jae-Il
    • Journal of Information Technology Services
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    • v.6 no.1
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    • pp.151-158
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    • 2007
  • D-class computation requires multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices and search for equivalent $n{\times}n$ Boolean matrices according to a specific equivalence relation. It is easy to see that even multiplying all $n{\times}n$ Boolean matrices with themselves shows exponential time complexity and D-Class computation was left an unsolved problem due to its computational complexity. The vector-based multiplication theory shows that the multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices can be done much more efficiently. However, D-Class computation requires computation of equivalent classes in addition to the efficient multiplication. The paper discusses a theory and an algorithm for efficient D-class computation, and shows execution results of the algorithm.

Experiments and numerical analyses for composite RC-EPS slabs

  • Skarzynski, L.;Marzec, I.;Tejchman, J.
    • Computers and Concrete
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    • v.20 no.6
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    • pp.689-704
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    • 2017
  • The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

A Study on the Word 'is' in a Sentence "A Parallelogram is Trapezoid." ("평행사변형은 사다리꼴이다."에서 '이다'에 대한 고찰)

  • Yi, Gyuhee;Choi, Younggi
    • School Mathematics
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    • v.18 no.3
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    • pp.527-539
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    • 2016
  • A word 'is' in "A parallelogram is trapezoid." is ambiguous and very rich when it comes to its meaning. In this paper, 'is' as in everyday language will be identified as semantic primes that can be interpreted in different ways depending on context and situation, and meanings of 'is' in mathematics will be discussed separately. Focusing on 'identity', 'is' will be reinterpreted in the view of equivalence relation and van Hieles' work. 'Is', as a mathematical sign, is thought to have a significant importance in producing mathematical ideas meaningfully.

Analytical Approximation Algorithm for the Inverse of the Power of the Incomplete Gamma Function Based on Extreme Value Theory

  • Wu, Shanshan;Hu, Guobing;Yang, Li;Gu, Bin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.12
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    • pp.4567-4583
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    • 2021
  • This study proposes an analytical approximation algorithm based on extreme value theory (EVT) for the inverse of the power of the incomplete Gamma function. First, the Gumbel function is used to approximate the power of the incomplete Gamma function, and the corresponding inverse problem is transformed into the inversion of an exponential function. Then, using the tail equivalence theorem, the normalized coefficient of the general Weibull distribution function is employed to replace the normalized coefficient of the random variable following a Gamma distribution, and the approximate closed form solution is obtained. The effects of equation parameters on the algorithm performance are evaluated through simulation analysis under various conditions, and the performance of this algorithm is compared to those of the Newton iterative algorithm and other existing approximate analytical algorithms. The proposed algorithm exhibits good approximation performance under appropriate parameter settings. Finally, the performance of this method is evaluated by calculating the thresholds of space-time block coding and space-frequency block coding pattern recognition in multiple-input and multiple-output orthogonal frequency division multiplexing. The analytical approximation method can be applied to other related situations involving the maximum statistics of independent and identically distributed random variables following Gamma distributions.

A cognitive psychological consideration of Michael Chehov's acting techniques (미카엘 체홉 연기 테크닉에 대한 인지심리학적 고찰)

  • Jin, Hyun-Chung;Cho, Joon-Hui
    • (The) Research of the performance art and culture
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    • no.37
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    • pp.365-389
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    • 2018
  • This research aims to study Michael Chekhov's acting techniques scientifically, because his techniques has been studied only theoretically or empirically. Especially, this study focuses on 'imagination' and 'Psychological Gesture' from the perspective of cognitive psychology. Chekhov thought 'imagination' as the basis and core of all the works of acting. In cognitive psychology, it is called as 'imagery' and means 'a representation of the mind of the object not communicated by the sensory organs currently'. This study starts with defining imagery and takes a brief look at the features and kinds of imagery. Then the researcher will prove scientifically the possibility of training acting using imagery as Chekhov's assertion. For the proof of the validity of imagery, we'll look for the theoretical evidences-functional equivalence hypothesis, psychoneuromuscular theory, symbolic learning theory, psychophygiological information processing-and experimental ones-measurements of cerebral blood flow or event-related potential, experiments with fMRI(functional magnetic resonance imaging) or PET(positron emission tomography). As a result, we can see that imagery is functionally identical to perception and improves fulfillment of cognitive and physical tasks. As proving physical changes can draw out psychological changes(feeling) on the medium of imagery, we can also see the validity of Psychological Gesture. From the above research, even if Chekhov developed the acting techniques only on the basis of his experience, his techniques can be thought as having scientific validity. Though insufficient, this study can be a help for actors or students as they using Chekhov's techniques.