• 대한수학회보
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• 제50권4호
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• pp.1157-1171
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• 2013

In this paper, by using the $q$-difference analogue of lemma on the logarithmic derivative lemma to re-establish some estimates of Nevanlinna characteristics of $f(qz)$, we deal with the value distribution and uniqueness of certain types of $q$-difference polynomials.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.51-54
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• 1990

A parametrization for a linear system is presented to design a direct model reference adaptive pole placement controler. This parametrized model is one of the structured nonminimal models. The exponentially weighted least-squres algorithm is employed to estimate the control parameters. The direct adaptive controller has the exponential weighting properties by the proposed method of selecting the characteristic polynomials of the sensitivity function filters in connection with the reference models.

• Kyungpook Mathematical Journal
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• 제28권1호
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• pp.39-44
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• 1988

In 1940, B. H. Neumann, working with a system more general than a near-field, proved that the additive group of such a system (and of a near-field) is commutative. The algebraic structure he used is known as a Neumann system (N-system). Here, the prime N-systems are classified and for each possible characteristic, examples of N-systems which are neither near-fields nor rings are given. It is also shown that a necessary condition for the set of all odd polynomials over GF(p) to be an N-system is that p is a Fermat prime.

• Korean Journal of Mathematics
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• 제32권1호
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• pp.97-107
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• 2024

Let A ⊆ B be an extension of integral domains with characteristic zero. Let H(A, B) and h(A, B) be rings of composite Hurwitz series and composite Hurwitz polynomials, respectively. We simply call H(A, B) and h(A, B) composite Hurwitz rings of A and B. In this paper, we study when H(A, B) and h(A, B) are unique factorization domains (resp., GCD-domains, finite factorization domains, bounded factorization domains).

• 대한수학회보
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• 제52권3호
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• pp.955-962
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• 2015

It has been established that the role played by complete graphs in graph theory is similar to the role Dowling group geometries and Projective geometries play in matroid theory. In this paper, we introduce a notion of H-tree, a class of representable matroids which play a similar role to trees in graph theory. Then we give some properties of H-trees such that when q = 0, then the results reduce to the known properties of trees in graph theory. Finally we give explicit expressions of the characteristic polynomials of H-trees, H-cycles, H-fans and H-wheels.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.664-669
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• 2005

In this note, we present a different asymptotes from the standard approximate lines of the Bode magnitude plot. Wherein the pseudo break frequency is defined in terms of coefficients of denominator and numerator polynomials of the transfer function instead of its poles and zeros. Several comparative examples are given. This result can be used for the characteristic ratio assignment(CRA) [1], [2] with frequency response requirements, which is a method of designing linear controller in parameter space.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권2호
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• pp.65-71
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• 2001

The step response of the Manabe standard form[2] has little overshoot and show almost same waveforms regardless of the order of the characteristic polynomials. In some situations it is difficult to control the rise time and settling time simultaneously of the step response of the Manabe standard form To control its rise time and settling time efficiently, We develop the Manabe standard form: We try to find out the SRFS(Slow Rise time & Fast Setting time) form which has the slower rise time and faster settling time than those fo the Manabe standard form. We also consider the other three forms: FRSS(Fast Rise time & Slow Settling time), SRFS(Slow Rise time & Fast Settling time) and SRSS(Slow Rise time & Slow Settling time) forms. In this paper, by using the evolutionary strategy, we obtain all the coefficient of the four forms we mention above. Finally, we design a controller for a given plant so that the overall system has the performance that the rise time is faster, the settling time is faster than those of the Manabe standard form.

• 정보보호학회논문지
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• 제12권3호
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• pp.77-85
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• 2002

선형 쉬프트 레지스터를 이용한 이진 난수 발생기의 연구는 1970년대부터 연구되어져 왔으며, 이러한 이진 난수열 발생기는 스트림 암호 기법에 이용되어졌다. 일반적으로, 이진 난수열 발생기는 최대 주기의 선형 쉬프트 레지스터와 선형 복잡도가 높은 난수를 발생시키기 위하여 비선형 여과함수 또는 비선형 결합함수로 구성된다. 그러므로, 높은 선형 복잡도 뿐만 아니라, 긴 주기를 갖는 이진 난수열의 생성은 스트림 암호 기법의 안전성을 평가하는데 중요한 요소가 된다. 일반적으로 L개의 레지스터와 1개의 궤환 함수 또는 특성 다항식으로 구성된 선형 쉬프트 레지스터의 최대 주기는 $2^L$-1을 넘을 수 없다. 본 논문에서는 L개의 레지스터와 2개의 부분 특성 다항식으로 구성된 새로운 이진 난수열 발생기를 제안한다. 제안된 이진 난수열 발생기는 초기 상태 값에 따라 기존의 선형 쉬프트 레지스터에서 생성한 수열의 주기와 같거나 긴 주기를 갖는 이진 난수열을 생성하며, 생성 수열의 선형복잡도 역시 증가된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.92-95
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• 1999

The design problem of the control system is the ability to synthesize controller that achieve robust stability and robust performance. The paper explains the Finite Inclusions Theorem (FIT) by the procedure namely FIT synthesis. It is developed for synthesizing robustly stabilizing controller for parametrically uncertain system. The fundamental problem in the study of parametrically uncertain system is to determine whether or not all the polynomials in a given family of characteristic polynomials is Hurwitz i.e., all their roots lie in the open left-half plane. By FIT it can prove a polynomial is Hurwitz from only approximate knowledge of the polynomial's phase at finitely many points along the imaginary axis. An example shows the simplicity of using the FIT synthesis to directly search for robust controller of parametrically uncertain system by way of solving a sequence of systems of linear inequalities. The systems of inequalities are solved via the projection method which is an elegantly simple technique fur solving (finite or infinite) systems of convex inequalities in an arbitrary Hilbert space. Results from example show that the controller synthesized by FIT synthesis is better than by H$\sub$$\infty$/ synthesis with parametrically uncertain system as well as satisfied the objectives for a considerably larger range of uncertainty.

• 물과 미래
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• 제27권2호
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• pp.155-166
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• 1994

Eulerian-Lagrangian 방법을 이용하여 1차원 종확산방정식의 수치모형을 비교·분석하였다. 본 연구에서서 비교·분석한 모형은 지배방정식을 연산자 분리방법에 의해서 이송만을 지배하는 이송방정식과 확산만을 지배하는 확산방정식으로 분리한다. 이송방정식은 특성곡선을 따라서 유체입자를 추적하는 특성곡선법을 사용하여 해를 구하고, 그 결과를 고정된 Eulerian 격자상에 보간하였고, 확산방정식은 상기 고정격자상에서 Crank-Nicholson 유한차분법을 사용하여 해를 구하였다. 이송방정식의 풀이에서 다양한 보간방법이 적용되었는데, 일반적으로 Hermite 보간다항식을 사용한 경우가 Lagrange 보간다항식을 사용한 경우보다 수치확산 및 수치진동 등의 오차를 최소화할 수 있어서 더욱 우수한 것으로 밝혀졌다.