• Research in Plant Disease
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• v.18 no.1
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• pp.45-48
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• 2012

In early August of 2011, following a prolonged period of cool and moist weather, several trees of boxelder maple (Acer negundo) planted in Mt. Soyo located in Dongducheon, Korea, were found to be heavily damaged by premature defoliation with zonate leaf spot symptoms. Numerous number of cone-shaped, white sporophores (conidia) were observed on lesions of the abaxial leaf surface. The morphological characteristics of conidia are of typical Cristulariella moricola, which was supported by analyzing sequences of internal transcribed spacer region of ribosomal DNA. Pathogenicity of the fungus was proved by artificial inoculation in the condition of relative humidity 100% and $18{\pm}2^{\circ}C$. This is the first report of the occurrence of zonate leaf spot caused by infection of C. moricola on A. negundo in Korea.

• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.721-732
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• 2012

The principal aim of the paper is to investigate new integral expression $${\int}_0^{\infty}x^{s+1}e^{-{\sigma}x^2}L_m^{(\gamma,\delta)}\;({\zeta};{\sigma}x^2)\;L_n^{(\alpha,\beta)}\;({\xi};{\sigma}x^2)\;J_s\;(xy)\;dx$$, where $y$ is a positive real number; $\sigma$, $\zeta$ and $\xi$ are complex numbers with positive real parts; $s$, $\alpha$, $\beta$, $\gamma$ and $\delta$ are complex numbers whose real parts are greater than -1; $J_n(x)$ is Bessel function and $L_n^{(\alpha,\beta)}$ (${\gamma};x$) is generalized Laguerre polynomials. Some integral formulas have been obtained. The Maple implementation has also been examined.

• Kyungpook Mathematical Journal
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• v.56 no.4
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• pp.1141-1160
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• 2016

In this paper, a symbolic algorithm for solving a regular initial value problem (IVP) for a system of linear differential-algebraic equations (DAEs) with constant coeffcients has been presented. Algebra of integro-differential operators is employed to express the given system of DAEs. We compute a canonical form of the given system which produces another simple equivalent system. Algorithm includes computing the matrix Green's operator and the vector Green's function of a given IVP. Implementation of the proposed algorithm in Maple is also presented with sample computations.

• The Korean Journal of Ecology
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• v.8 no.2
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• pp.99-107
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• 1985

Photosynthetically Active Radiation (PAR) affects the growth of plants as well as their photosynthetic rates. A mathematical model for intercepted solar radiation on the tilted leaf with any azimuth angle was established and the leaf orientation in which receives the maximum solar radiation was determined each month, during the growing season, and for an year. PAR was maximized at the leaf elevation of 50。~60。 in the winter, at that of 20。~40。. On the whole the leaves of tilt angle 0。~40。 received much radiation comparing with those of other tilt angles. The theoretical tendencies were compared with the distribution of leaf orientation measused practically. The average leaf elevation of maple tree was 17.0。$\pm$12.0。, and that of ginkgo was 29.8。$\pm$16.0。. Several results from other literatures support our suggestion that cumulative effevct of the relationships between surface normal vector and a vector pointing in the direction of the radiation determine the leaf orientation.

• Journal of applied mathematics & informatics
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• v.10 no.1_2
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• pp.63-73
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• 2002

The governing equation locating component centers in the degree-n bifurcation set is a polynomial with a very high degree and its root-finding lacks numerical accuracy. The equation is transformed to have its degree reduced by a factor(n-1). Newton's method applied to the transformed equation improves the accuracy with properly chosen initial values. The numerical implementation is done with Maple V using a large number of computational precision digits. Many cases are studied for 2 $\leq$ n $\leq$ 25 and show a remarkably improved computation.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1571-1581
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• 2011

In this paper, we construct inequivalent Hadamard matrices based on several new and old full orthogonal designs, using circulant and symmetric block matrices. Not all orthogonal designs produce inequivalent Hadamard matrices, because the corresponding systems of equations do not possess solutions. The systems of equations arising when we search for inequivalent Hadamard matrices from full orthogonal designs using circulant and symmetric block matrices, can be concisely described using the periodic autocorrelation function of the generators of the block matrices. We use Maple, Magma, C and Unix tools to find many new inequivalent Hadamard matrices.

• Research in Mathematical Education
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• v.11 no.2
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• pp.143-151
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• 2007

Nowadays there are practically no mathematical courses in which Computer Algebra Systems (CAS) programs, such as MATHEMATlCA, Maple, and TI-89/92, are not used to some extent. However, generally the usage of these programs is reduced to illustration of computing processes: calculation of integrals, differentiation, solution of various equations, etc. This is obtained by usage of standard command of type: Solve [...] in MATHEMATICA. At the same time the main difficulties arise at teaching nonconventional mathematical courses such as coding theory, discrete mathematics, cryptography, Scientific computing, which are gaining the increasing popularity now. Now it is impossible to imagine a modern engineer not having basic knowledge in discrete mathematics, Cryptography, coding theory. Digital processing of signals (digital sound, digital TV) has been introduced in our lives.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.389-392
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• 2004

정합장처리를 이용한 표적의 탐지는 다양한 종류의 간섭표적들이 존재하는 환경에서 수행될 가능성이 크며, 따라서 분해능이 높은 적응 정합장처리를 사용이 요구된다. 반면 빠르게 움직이는 고소음의 간섭표적이 존재 할 경우에는 적응정합장처리를 수행하기위한 신호단편 (snapshot) 수를 충분하게 사용할 수 없는 상황에 직면하게 된다. 제한된 신호단편을 이용하여 적응정합장처리의 CSDM (cross-spectral density matrix)을 안정적으로 추정하기 위한 목적으로 선형빔형성에서 제안되었던 광대역 STMV (steered minimum varianve) 기법을 도입하였다. MAPLE03 실험환경을 이용하여 STMV의 적응정합장처리 수치실험을 수행하고 특성을 분석하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.377-380
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• 2004

정합장처리는 음파를 이용하여 해양환경 변수와 표적의 위치를 추정하는 신호처리 기법을 말한다. 이를 연구 하기 위하여 2003년 10월, 2004년 5월과 10월 등 3차례에 걸쳐 음향실험을 실시하였다. 동해시 앞의 수심 100-150 해당하는 대륙붕 지역에 20채널의 수직 선배열 센서를 설치하고 저주파 예인 음원기, 토모그래피 음원, 전구 발파기를 이용하여 음향신호를 획득하였다. 측정된 해양 및 음향자료와 실험 해역에 대한 지음향 데이터 베이스를 이용하여 일차적으로 음원의 위치 및 지음향 변수를 추정하는 분석을 실시하였다. 국방과학연구소, 한양대학교, 서울대학교가 참여하는 공동실험은 앞으로 3차례 더 실시할 계획에 있다.

• Journal of the Korean Mathematical Society
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• v.54 no.4
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• pp.1209-1229
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• 2017

We coupled the so-called Sumudu transform with the homotopy perturbation method (HPM) and the homotopy analysis method (HAM), which are called homotopy perturbation Sumudu transform method (HPSTM) and homotopy analysis Sumudu transform method (HASTM), respectively. Then we show how HPSTM and HASTM are more convenient than HPM and HAM by conducting a comparative analytical study for a system of time fractional nonlinear differential equations. A Maple package is also used to enhance the clarity of the involved numerical simulations.