• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.505-510
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• 2011

We give a constructive proof that a (partial) evaluation of a multivariate algebraic function with algebraic numbers is again an algebraic function. Especially, we obtain a bound on the degree of an evaluation with the degrees of the original algebraic function and the algebraic numbers evaluated. Furthermore, we show that our bound is sharp with an example.

• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1522-1539
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• 2002

In the present study, an explicit algebraic stress model is shown to be the exact tensor representation of algebraic stress model by directly solving a set of algebraic equations without resort to tensor representation theory. This repeals the constraints on the Reynolds stress, which are based on the principle of material frame indifference and positive semi-definiteness. An a priori test of the explicit algebraic stress model is carried out by using the DNS database for a fully developed channel flow at Rer = 135. It is confirmed that two-point correlation function between the velocity fluctuation and the Laplacians of the pressure-gradient i s anisotropic and asymmetric in the wall-normal direction. Thus, a novel composite algebraic Reynolds stress model is proposed and applied to the channel flow calculation, which incorporates non-local effect in the algebraic framework to predict near-wall behavior correctly.

• 정보보호학회논문지
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• 제15권6호
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• pp.105-110
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• 2005

유한체에서 정의된 선형 다항식의 역원은 함수 거 일반화로 볼 수 있으므로, 암호학적 응용에서 유용한 부울 하수를 설계하는 데 좋은 후보가 될 수 있다 특히, Crypto 2001에서는 선형 다항식 및 선형 부호를 이용하여 큰 대수적 차수를 가지는 resilient 함수를 설계하는 방법이 제안되었다. 그러나 Crypto 2001에서 대수적 차수를 분석한 결과에 오류가 있었으며, 본 논문에서 정확한 대수적 차수를 제시한다.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권6호
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• pp.259-265
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• 2001

In the last two decades, many researchers proposed various usages of the orthogonal functions such as Walsh, Haar and BPF to solve the system analysis, optimal control, and identification problems from and algebraic form. In this paper, a simple procedure to design and algerbraic observer for the descriptor system is presented by using block pulse function expansions. The main characteristic of this technique is that it converts differential observer equation into an algerbraic equation. And furthermore, a simple recursive algorithm is proposed to obtain BPFs coefficients of the observer equation.

• 대한수학회지
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• 제31권4호
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• pp.569-608
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• 1994

The subject matter of this survey has to do with holomorphic maps from a compact Riemann surface to projective space, which are also called algebrac curves; the theory we survey lies at the crossroads of function theory, projective geometry, and commutative algebra (although we should mention that the present survey de-emphasizes the algebraic aspect). Algebraic curves have been vigorously and continuously investigated since the time of Riemann. The reasons for the preoccupation with algebraic curves amongst mathematicians perhaps have to do with-other than the usual usual reason, namely, the herd mentality prompting us to follow the leads of a few great pioneering methematicians in the field-the fact that algebraic curves possess a certain simple unity together with a rich and complex structure. From a differential-topological standpoint algebraic curves are quite simple as they are neatly parameterized by a single discrete invariant, the genus. Even the possible complex structures of a fixed genus curve afford a fairly complete description. Yet there are a multitude of diverse perspectives (algebraic, function theoretic, and geometric) often coalescing to yield a spectacular result.

• 조명전기설비학회논문지
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• 제20권5호
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• pp.116-124
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• 2006

비등간격 접지Grid의 설계는 등간격 접지Grid의 설계의 문제점을 극복할 수 있으나 최근까지 국내에서는 적절한 비등간격 접지Grid의 설계방법이나 비등간격 접지Grid 간격결정 방법은 논의되고 있지 않다. 따라서 본 논문에서는 일차함수, 루트함수, 다항함수인 대수함수제어를 통한 비등간격 접지Grid의 수식을 유도하고 최대 Mesh전위와 최소Mesh 전위의 전위차가 2[%] 이내가 되도록 최적의 간격비율을 제시한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2086-2088
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• 2002

This paper deals with an algebraic approach for unknown inputs observer by using Haar functions. In the algebraic UIO(unknown input observer) design procedure, coordinate transformation method is adopted to derive the reduced order dynamic system which is decoupled unknown inputs and Haar function and its integral operational matrix is applied to avoid additional differentiation of system outputs.

• 대한수학회논문집
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• 제17권4호
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• pp.619-623
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• 2002

In this paper, we study transnormal systems on the Euclidean and semi-Euclidean spaces. We classified transnormal systems on Rf" . We also prove that transnormal systems on R$\^$n/$\sub$p/ are algebraic even though there are non-algebraic isoparametric hypersurfaces.

• 호남수학학술지
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• 제21권1호
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• pp.105-113
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• 1999

Suppose that ${\Omega}$ is a bounded domain with $C^{\infty}$ smooth boundary in the plane whose associated Bergman kernel, exact Bergman kernel, or $Szeg{\ddot{o}}$ kernel function is an algebraic function. We shall prove that any proper holomorphic mapping of ${\Omega}$ onto the unit disc is algebraic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2082-2084
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• 2003

A practical real-time LOS rate estimator is proposed to handle the time-varying measurement noise statistics. To calculate the optimal Kalman gain, the algebraic transformation method is taken into account. By using the algebraic transformation, the differential algebraic Riccati equation(DARE) regarding estimation error covariance is replaced by the simple algebraic Riccati equation(ARE). The proposed LOS estimation filter gain is only a function of relative range. Consequently, the proposed method is computationally very efficient and suitable for embedded environment.