• Bulletin of the Korean Mathematical Society
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• v.41 no.2
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• pp.257-267
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• 2004

In this paper, we introduce, for each approximate distribution $\~{T}$ of [a, b], the approximate Henstock-Stieltjes integral with value in Banach spaces. The Henstock integral is a special case of this where $\~{T}\;=\;\{(\tau,\;[a,\;b])\;:\;{\tau}\;{\in}\;[a,\;b]\}$. This new concept generalizes Henstock integral and abstract Perron-Stieltjes integral. We establish a uniform convergence theorem for approximate Henstock-Stieltjes integral, which is an improvement of the uniform convergence theorem for Perron-Stieltjes integral by Schwabik [3].

• Structural Engineering and Mechanics
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• v.3 no.6
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• pp.541-553
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• 1995

The determination of the stress intensity factors is investigated by using the surface integral defined around the crack tip of the structure. In this work, the integral method is derived naturally from the standard path integral J. But the use of the surface integral is also extended to the case where body forces act. Computer program for obtaining the stress intensity factors $K_I$ and $K_{II}$ is developed, which prepares input variables from the result of the conventional finite element analysis. This paper provides a parabolic smooth curve function. By the use of the function and conventional element meshes in which the aspect ratio (element length at the crack tip/crack length) is about 25 percent, relatively accurate $K_I$ and K_{II}$ values can be obtained for the outer integral radius ranging from 1/3 to 1 of the crack length and for inner one zero.

• Structural Engineering and Mechanics
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• v.28 no.4
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• pp.461-477
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• 2008

An adaptive finite element method for analyzing two-dimensional and axisymmetric nonlinear elastic fracture mechanics problems with cracks is presented. The J-integral is used as a parameter to characterize the severity of stresses and deformation near crack tips. The domain integral technique, for which all relevant quantities are integrated over any arbitrary element areas around the crack tips, is utilized as the J-integral solution scheme with 9-node degenerated crack tip elements. The solution accuracy is further improved by incorporating an error estimation procedure onto a remeshing algorithm with a solution mapping scheme to resume the analysis at a particular load level after the adaptive remeshing technique has been applied. Several benchmark problems are analyzed to evaluate the efficiency of the combined domain integral technique and the adaptive finite element method.

• Journal for History of Mathematics
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• v.18 no.3
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• pp.107-117
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• 2005

In this paper, we introduce linear approximate Henstock integral equations that is slightly different from linear Henstock integral equations, and we also offer an example which shows that some integral equation has a solution in the sense of the approximate Henstock integral but does not have any solutions in the sense of the Henstock integral. Furthermore, we investigate the existence and uniqueness of solution of the approximate Henstock integral equation.

• Journal of the Chungcheong Mathematical Society
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• v.12 no.1
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• pp.157-162
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• 1999

In this paper, we introduce approximate Perron-Stieltjes integral and approximate Roussel derivative and investigate the differentiability of indefinite approximate Perron-Stieltjes integral.

• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.569-579
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• 1997

We investigate the existence of the operator-valued Feynman integral when a Wiener functional is given by a Fourier transform of complex Borel measure.

• Journal for History of Mathematics
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• v.14 no.2
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• pp.21-28
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• 2001

In this paper we introduce the Feynman integral which is one of the function space integrals. There are so many approaches to the Feynman integral. Here we treat tile analytic Feynman integral and the operator-valued Feynman integral.

• Journal of the Korean Mathematical Society
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• v.38 no.2
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• pp.437-468
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• 2001

This paper is an exposition of the relationship between Witten's functional integral and Vassiliev invariants.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.949-956
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• 2009

The C(t)-integral describes amplitude of stress and strain rate field near a tip of stationary crack under transient creep condition. Thus the C(t)-integral is a key parameter for the high-temperature crack assessment. Estimation formulae for C(t)-integral of the cracked component operating under mechanical load alone have been provided for decades. However, high temperature structures usually work under combined mechanical and thermal load. And no investigation has provided quantitative estimates for the C(t)-integral under combined mechanical and thermal load. In this study, 3-dimensional finite element analyses were conducted to calculate the C(t)-integral of elastic-creep material under combined mechanical and thermal load. As a result, redistribution time for the crack under combined mechanical and thermal load is re-defined through FE analyses to quantify the C(t)-integral. Estimates of C(t)-integral using this proposed redistribution time agree well with FE analyses results.

• Journal for History of Mathematics
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• v.22 no.4
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• pp.145-160
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• 2009

In the end of 20th century, the concept of p-adic invariant q-integral was introduced by Taekyun Kim. The p-adic invariant q-integral is the extension of Jackson's q-integral on complex space. It is also considered as the answer of the question whether the ultra non-archimedian integral exists or not. In this paper, we investigate the background of historical mathematics for the p-adic invariant q-integral on $Z_p$ and the trend of the research in this field at present.