• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.275-282
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• 2001

In this paper, nonlinear analyses of RC (Reinforced Concrete) columns are conducted, and an improved criterion to estimate the design load carrying capacity of slender RC columns is proposed. To simulate the material nonlinearty including the cracking of concrete, the layer model is adopted, and the initial stress matrix is considered for the simulation of P- effect. After correlation studies with previous numerical results to verify the efficiency of the developed numerical model, many parameter studies are followed, and a regression formula which can give more exact resisting capacity of slender RC columns is introduced on the basis of the obtained numerical results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.04a
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• pp.1-5
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• 1990

The object of this study introducts simple formula being based on energy principle to investigate span truss's non-linear, and considers the relation of member's length, height rate and slenderness ratio to rise prymid truss's economic structure ability through each example. This paper considered space truss's geometric non-linear behavior and material non-linear behavior, so acquired under result through as saying energy principle.

• Communications of the Korean Mathematical Society
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• v.38 no.2
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• pp.355-364
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• 2023

In this paper, we investigate the sums of the elements in the finite set $\{x^k:1{\leq}x{\leq}{\frac{n}{m}},\;gcd_u(x,n)=1\}$, where k, m and n are positive integers and gcd_u(x, n) is the unitary greatest common divisor of x and n. Moreover, for some cases of k and m, we can give the explicit formulae for the sums involving some well-known arithmetic functions.

• Communications for Statistical Applications and Methods
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• v.22 no.6
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• pp.665-674
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• 2015

Lack of a general matrix formula hampers implementation of the semi-partial correlation, also known as part correlation, to the higher-order coefficient. This is because the higher-order semi-partial correlation calculation using a recursive formula requires an enormous number of recursive calculations to obtain the correlation coefficients. To resolve this difficulty, we derive a general matrix formula of the semi-partial correlation for fast computation. The semi-partial correlations are then implemented on an R package ppcor along with the partial correlation. Owing to the general matrix formulas, users can readily calculate the coefficients of both partial and semi-partial correlations without computational burden. The package ppcor further provides users with the level of the statistical significance with its test statistic.

• Journal of applied mathematics & informatics
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• v.15 no.1_2
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• pp.363-375
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• 2004

In this paper, We show that the bandpass random signals of the form ∑$_{\alpha}$$\alpha$$_{\alpha}$ a Sin(2$\pi$f$_{\alpha}$t + b$_{\alpha}$) where a$_{\alpha}$ being a random number in [0,1], f$_{\alpha}$ a random integer in a given frequency band, and b$_{\alpha}$ a random number in [0, 2$\pi$], generate Gaussian white noise signals and hence they are adequate for simulating Continuous Markov processes. We apply the result to the fluctuation-dissipation formula for the Johnson noise and show that the probability distribution for the long term average of the power of the Johnson noise is a X$^2$ distribution and that the relative error of the long term average is (equation omitted) where N is the number of blocks used in the average.error of the long term average is (equation omitted) where N is the number of blocks used in the average.

• Journal of applied mathematics & informatics
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• v.30 no.1_2
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• pp.135-145
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• 2012

Traditionally, ERM (Equivalent Random Method) is used to determine number of circuits in an overflow circuit group with rough traffic which has vmr(variance to mean ratio) greater than one. Recently, IPP(Interrupted Poisson Process) approximate method which represents the collective feature of the overflow has been introduced. The negative binomial loss formula can be applied to determine the required number of circuits in the overflow circuit group. In this paper, we deal with the negative binomial loss formula and determination method of number of circuits. We also analyze and compare these three loss formulas.

• Journal of Applied and Pure Mathematics
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• v.6 no.5_6
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• pp.283-299
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• 2024

This article presents a fundamental generalization of the classical Fibonacci sequence. We introduce a general 2^nd order recurrence relation, V_n = pV_n-1 + qV_n-2, q ≠ 0, n ≥ 2, with initial terms V₀(= a), V₁(= b), a, b, p, and q are any non-zero real numbers. We derive an explicit generalized form of the generating function and comprehensive Binet's formula, which comprehend this concept to various sequences that follow similar recurrence relations. Furthermore, we analyze more generalized and specialized cases, uncovering new and existing identities for well-known sequences such as Fibonacci, Lucas, Pell, Pell-Lucas, Goksal Bilgici, and others. Our analysis implicitly reveals identities like Cassini's, Catalan's, d'Ocagne's, and Gelin-Cesàro in the generalized form. Additionally, tabular and graphical representations are provided to illustrate the relationships between the terms of these sequences.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.369-379
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• 2018

We consider a p-adic Euler L-function of two variables which interpolate the generalized Euler polynomials at nonpositive integers. We also show that the reflection formula and the functional equation for these functions.

• Journal of applied mathematics & informatics
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• v.23 no.1_2
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• pp.445-453
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• 2007

This paper deals with the approximate controllability for the nonlinear functional differential equations with time delay and studies a variation of constant formula for solutions of the given equations.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.42-48
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• 1998

Numerical study is presented for the analysis of three-dimensional incompressible turbulent flows in multiblade centrifugal fan. Reynolds-averaged Navier-Stokes equations with standard k - $\epsilon$ turbulence model are transformed to non-orthogonal curvilinear coordinates, and are discretized with finite volume approximations. Linear Upwind Differencing Scheme(LUDS) is used to approximate the convection terms in the governing equations. SIMPLEC algorithm is used as a velocity-pressure correction procedure. The computational area is divided into three blocks; core, impeller and scroll, which are linked by multi-block method. The flow inside of the fan is regarded as steady flow, and mathematical formula established from the cascade theory and empirical coefficient are employed to simulate tile flow through the impeller. From comparisons between the computational results and the experimental data, the validity of the mathematical formula for the blade forces was examined and good results were obtained qualitatively. Hence, we can get the flow characteristics of multi-blade centrifugal fan and it will be a corner stone of the development of the multiblade centrifugal fan.