• 대한전기학회논문지
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• 제33권10호
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• pp.381-386
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• 1984

This paper deals with the microcomputer realization of EMG pattern recognition system which provides identification of motion commands from the EMG signals for the on-line control of a prosthetic arm. A probabilistic model of pattern is formulated in the feature space of integral absolute value(IAV) to describe the relation between a motion command and the location of corresponding pattern. This model enables the derivation of sample density function of a command in the feature space of IAV. Classification is caried out through the multiclass sequential decision process, where the decision rule and the stopping rule of the process are designed by using the simple mathematical formulas defined as the likelihood probability and the decision measure, respectively. Some floating point algorithms such as addition, multiplication, division, square root and exponential function are developed for calculating the probability density functions and the decision measure. Only six primitive motions and one no motion are incorporated in this paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.223-226
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• 2001

In this paper, dc link ripple currents for three-phase ac/dc/ac PWM converters are analyzed in a frequency domain. The expression of the harmonic currents is developed by using switching functions and exponential Fourier series expansion. The dc link ripple currents with regard to power factor and modulation index are investigated. In addition, the effect of the displacement angle between the switching periods of line-side converters and load-side inverters on the do link ripple current is studied. The result of the do link current analysis is helpful in specifying the dc link capacitor size and its life time estimation.

• 대한수학회지
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• 제42권3호
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• pp.573-597
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• 2005

A continuous linear operator T, on the space of entire functions in d variables, is PDE-preserving for a given set $\mathbb{P}\;\subseteq\;\mathbb{C}|\xi_{1},\ldots,\xi_{d}|$ of polynomials if it maps every kernel-set ker P(D), $P\;{\in}\;\mathbb{P}$, invariantly. It is clear that the set $\mathbb{O}({\mathbb{P}})$ of PDE-preserving operators for $\mathbb{P}$ forms an algebra under composition. We study and link properties and structures on the operator side $\mathbb{O}({\mathbb{P}})$ versus the corresponding family $\mathbb{P}$ of polynomials. For our purposes, we introduce notions such as the PDE-preserving hull and basic sets for a given set $\mathbb{P}$ which, roughly, is the largest, respectively a minimal, collection of polynomials that generate all the PDE-preserving operators for $\mathbb{P}$. We also describe PDE-preserving operators via a kernel theorem. We apply Hilbert's Nullstellensatz.

• 산업공학
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• 제13권2호
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• pp.217-224
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• 2000

This paper analyzes the effects of setup cost reduction in a dynamic lot-sizing model for a single-facility multi-product problem. In the model, demands for each product are known, no backlogging is allowed, and a single resource is employed. Also, setup cost is defined as a function of capital expenditure to invest in setup cost reduction. Furthermore, in each production period the facility (or plant) produces many products, each representing a fixed part of the involved production activity (or input resource quantity). In this paper, the structure of the optimal solution is characterized and an efficient algorithm is proposed for simultaneously determining the optimal lot size with reduced setup cost and the optimal investment in setup cost reduction. Also, the proposed algorithm is illustrated by a numerical example with a linear and an exponential setup reduction functions.

• Bulletin of the Korean Chemical Society
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• 제6권1호
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• pp.3-7
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• 1985

The general formulas for SCF atomic orbitals |5s > and |6p > have been derived separately by expressing the spherical harmonics part in terms of the coordinate($r_1,\;$r_2$) of the reference point, and by translating the exponential part, $r^4\;exp\;(-{\beta}r)$), in terms of $r_1,\;and\;r_2$ and the modified Bessel functions. Master formulas for overlap and dipole moment matrix elements are derived. The computed values of overlap and dipole moment matrix elements for hypothetical NO molecule are exactly in agreement with those for the previous methods.

• Bulletin of the Korean Chemical Society
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• 제18권4호
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• pp.424-427
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• 1997

To study the NMR chemical shift arising from the 5f-electron orbital angular momentum and the 5f-electron spin dipolar-nuclear spin angular momentum interactions, the evaluation of the hyperfine integrals has been extended to any pairs of SCF type 5f orbitals adopting a general method which is applicable to a general vector R, pointing in any direction in space. From the electronic wavefunctions for 5f orbitals expressed in common coordinate system, the radial part of the hyperfine interaction integrals are derived by translating the exponential part, r2 exp(-2βr), in terms of R, rN and the modified Bessel functions. The radial integals for 5f orbitals are tabulated in analytical forms. When two of the hyperfine integrals along the (100), (010), (001), (110), and (111) axes are calculated using the derived radial integrals, the calculated values for the 5f system change sign for R-values larger than R　0.35 nm. But the calculated values for the 4f systems change sign for R-values larger than R　0.20 nm.

• 대한수학회논문집
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• 제37권3호
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• pp.939-955
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• 2022

In this paper, we study a first-order non-linear singularly perturbed Volterra integro-differential equation (SPVIDE). We discretize the problem by a uniform difference scheme on a Bakhvalov-Shishkin mesh. The scheme is constructed by the method of integral identities with exponential basis functions and integral terms are handled with interpolating quadrature rules with remainder terms. An effective quasi-linearization technique is employed for the algorithm. We establish the error estimates and demonstrate that the scheme on Bakhvalov-Shishkin mesh is O(N^-1) uniformly convergent, where N is the mesh parameter. The numerical results on a couple of examples are also provided to confirm the theoretical analysis.

• 대한수학회논문집
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• 제38권3호
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• pp.943-966
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• 2023

In this paper, we study the initial-boundary value problem for viscoelastic wave equations of Kirchhoff type with Balakrishnan-Taylor damping terms in the presence of the infinite memory and external time-varying delay. For a certain class of relaxation functions and certain initial data, we prove that the decay rate of the solution energy is similar to that of relaxation function which is not necessarily of exponential or polynomial type. Also, we show another stability with g satisfying some general growth at infinity.

• Steel and Composite Structures
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• 제45권4호
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• pp.535-546
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• 2022

The memory response of nonlocal systematical formulation size-dependent coupling of viscoelastic deformation and thermal fields for piezoelectric materials with dual-phase lag heat conduction law is constructed. The method of the matrix exponential, which constitutes the basis of the state-space approach of modern control theory, is applied to the non-dimensional equations. The resulting formulation together with the Laplace transform technique is applied to solve a problem of a semi-infinite piezoelectric rod subjected to a continuous heat flux with constant time rates. The inversion of the Laplace transforms is carried out using a numerical approach. Some comparisons of the impacts of nonlocal parameters and time-delay constants for various forms of kernel functions on thermal spreads and thermo-viscoelastic response are illustrated graphically.

• 대한수학회보
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• 제60권6호
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• pp.1673-1685
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• 2023

Inspired by Hongjie Dong and Qi S. Zhang's article [3], we find that the analyticity in time for a smooth solution of the heat equation with exponential quadratic growth in the space variable can be extended to any complete noncompact Riemannian manifolds with Bakry-Émery Ricci curvature bounded below and the potential function being of at most quadratic growth. Therefore, our result holds on all gradient Ricci solitons. As a corollary, we give a necessary and sufficient condition on the solvability of the backward heat equation in a class of functions with the similar growth condition. In addition, we also consider the solution in certain L^p spaces with p ∈ [2, +∞) and prove its analyticity with respect to time.