• 대한수학회지
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• 제54권3호
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• pp.835-845
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• 2017

The $GCF_{\epsilon}$ expansion is a new class of continued fractions induced by the transformation $T_{\epsilon}:(0, 1]{\rightarrow}(0, 1]$: $T_{\epsilon}(x)={\frac{-1+(k+1)x}{1+k-k{\epsilon}x}}$ for $x{\in}(1/(k+1),1/k]$. Under the algorithm $T_{\epsilon}$, every $x{\in}(0,1]$ corresponds to an increasing digits sequences $\{k_n,n{\geq}1\}$. Their basic properties, including the ergodic properties, law of large number and central limit theorem have been discussed in [4], [5] and [7]. In this paper, we study the large deviation for the $GCF_{\epsilon}$ expansion and show that: $\{{\frac{1}{n}}{\log}k_n,n{\geq}1\}$ satisfies the different large deviation principles when the parameter ${\epsilon}$ changes in [-1, 1], which generalizes a result of L. J. Zhu [9] who considered a case when ${\epsilon}(k){\equiv}0$ (i.e., Engel series).

• 한국정보과학회논문지:소프트웨어및응용
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• 제35권8호
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• pp.501-511
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• 2008

프로브(probe) 디자인은 성공적인 DNA 마이크로어레이(DNA microarray) 실험을 위해서 필수적인 작업이다. 프로브가 만족시켜야 하는 조건은 마이크로어레이 실험의 목적이나 방법에 따라 다양하게 정의될 수 있는데, 대부분의 기존 연구에서는 각각의 조건에 대하여 각자 독립적으로 정해진 한계치(threshold) 값을 넘지 않는 프로브를 탐색하는 방법을 취하고 있다. 그러나, 본 연구에서는 프로브 디자인을 두가지 목적함수를 지닌 다중목적함수 최적화 문제(multiobjective optimization problem)로 정의하고, ${\epsilon}$-다중목적함수 진화 알고리즘(${\epsilon}$-multiobjective evolutionary algorithm)을 이용하여 해결하는 방법을 제시한다. 제시된 방법은 19종류의 고위험군 인유두종 바이러스(Human Papillomavirus) 유전자들에 대한 프로브 디자인과 52종류의 애기장대 칼모듈린 유전자군(Arabidopsis Calmodulin multigene family)에 대한 프로브 디자인에 각각 적용되었다. 제안한 방법론을 사용하여 기존의 공개 프로브 디자인 프로그램인 OligoArray 및 OligoWiz에 비해 목표유전사에 더 적합한 프로브를 찾을 수 있었다.

• 정보과학회 논문지
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• 제44권1호
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• pp.63-70
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• 2017

본 논문에서는 확률적 보상과 유효성을 갖고, 매 시간 유효한 arm들의 집합이 변하는 sleeping bandit 문제를 해결하는 다수의 전략들의 집합 ${\Phi}$가 주어졌을 때, 이들을 융합하는 문제를 고려하고, 이 문제를 해결하기 위한 융합 알고리즘 sleepComb(${\Phi}$)를 제안한다. 제안된 알고리즘인 sleepComb(${\Phi}$)는 확률적(stochastic) multi-armed bandit 문제를 해결하는 매개변수 기반 휴리스틱으로 잘 알려진 ${\epsilon}_t$-greedy의 확률적 스위칭 기법을 바탕으로 매 시간 적절한 전략을 선택하는 알고리즘이다. 시퀀스 {${\epsilon}_t$}와 전략들에 대한 적절한 조건이 주어졌을 때, 알고리즘 sleepComb(${\Phi}$)는 sleeping bandit 문제에 대해 적절히 정의된 "best" 전략으로 수렴한다. 실험을 통해 이 알고리즘이 "best" 전략으로 수렴한다는 사실을 확인하고, 기존의 다른 융합 알고리즘보다 "best" 전략으로 더 빠르게 수렴함과 "best" 전략을 선택하는 비율이 더 높음을 보인다.

• Structural Engineering and Mechanics
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• 제37권5호
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• pp.475-487
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• 2011

In a flexible multi-body dynamic system the typical topological optimization method for structures cannot be directly applied, as the stiffness varies with position. In this paper, the topological optimization of the flexible multi-body dynamic system is converted into structural optimization using the equivalent static load method. First, the actual boundary conditions of the control system and the approximate stiffness curve of the mechanism are obtained from a flexible multi-body dynamical simulation. Second, the finite element models are built using the absolute nodal coordination for different positions according to the stiffness curve. For efficiency, the static reanalysis method is utilized to solve these finite element equilibrium equations. Specifically, the finite element equilibrium equations of key points in the stiffness curve are fully solved as the initial solution, and the following equilibrium equations are solved using a reanalysis method with an error controlled epsilon algorithm. In order to identify the efficiency of the elements, a non-dimensional measurement is introduced. Finally, an improved evolutional structural optimization (ESO) method is used to solve the optimization problem. The presented method is applied to the optimal design of a die bonder. The numerical results show that the presented method is practical and efficient when optimizing the design of the mechanism.

• 대한기계학회논문집B
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• 제23권5호
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• pp.610-620
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• 1999

Recently, numerous modifications of low Reynolds number $k-{\epsilon}$ model have boon carried out with the aid of DNS data. However, the previous models made in this way are too intricate to be used practically. To overcome this shortcoming, a new low Reynolds number $k-{\epsilon}$ model has boon developed by considering the distribution of turbulent properties near the wall. This study proposes the revised a turbulence model for prediction of turbulent flow with adverse pressure gradient and separation. Nondimensional distance $y^+$ in damping functions is changed to $y^*$ and some terms modeled for one dimensional flow in $\epsilon$ equations are expanded into two or three dimensional form. Predicted results by the revised model show an acceptable agreement with DNS data and experimental results. However, for a turbulent flow with severe adverse pressure gradient, an additive term reflecting an adverse pressure gradient effect will have to be considered.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.457-473
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• 2005

In each step of the quasi-minimal residual (QMR) method which uses a look-ahead variant of the nonsymmetric Lanczos process to generate basis vectors for the Krylov subspaces induced by A, it is necessary to decide whether to construct the Lanczos vectors $v_{n+l}\;and\;w{n+l}$ as regular or inner vectors. For a regular step it is necessary that $D_k\;=\;W^{T}_{k}V_{k}$ is nonsingular. Therefore, in the floating-point arithmetic, the smallest singular value of matrix $D_k$, ${\sigma}_min(D_k)$, is computed and an inner step is performed if $\sigma_{min}(D_k)<{\epsilon}$, where $\epsilon$ is a suitably chosen tolerance. In practice it is absolutely impossible to choose correctly the value of the tolerance $\epsilon$. The subject of this paper is to show how discrete stochastic arithmetic remedies the problem of this tolerance, as well as the problem of the other tolerances which are needed in the other checks of the QMR method with the estimation of the accuracy of some intermediate results. Numerical examples are used to show the good numerical properties.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2083-2088
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• 2003

This study was performed to analyze the velocity and temperature distributions of the land aquaculture tank for fish breeding. In this study, we analyzed the velocity and temperature distributions in aquarium tank, and the finite volume method and standard ${\kappa}-{\epsilon}$ turbulence model with the SIMPLE computational algorithm are used to study the water flow in the aquarium. The main calculation parameters of the aquarium tank are the inlet flow rate with from 0.5 to 2.0L/M.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.10-13
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• 1995

This paper considers the linear-quadratic optimal regulator problem for nonstandard singularly perturbed systems making use of the recursive technique. We first derive a generalized Riccati differential equation by the Hamilton-Jacobi equation. In order to obtain the feedback gain, we must solve the generalized algebraic Riccati equation. Using the recursive technique, we show that the solution of the generalized algebraic Riccati equation converges with the rate of convergence of O(.epsilon.). The existence of a bounded solution of error term can be proved by the implicit function theorem. It is enough to show that the corresponding Jacobian matrix is nonsingular at .epsilon. = 0. As a result, the solution of optimal regulator problem for nonstandard singularly perturbed systems can be obtained with an accuracy of O(.epsilon.$^{k}$ ). The proposed technique represents a significant improvement since the existing method for the standard singularly perturbed systems can not be applied to the nonstandard singularly perturbed systems.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (A)
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• pp.82-84
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• 2006

최근의 생물학적인 연구에 DNA microarray가 널리 쓰이고 있기 때문에, 이러한 DNA microarray를 구성하는데 필요한 probe design 작업의 중요성이 점차 커져가고 있다. 이 논문에서는 probe design 문제를 thermodynamic fitness function이 2개인 multi-objective optimization 작업으로 변환한 뒤, ${\epsilon}$-multiobjective evolutionary algorithm을 이용하여 probe set을 찾는다. 또한, probe 탐색공간의 크기를 줄이기 위하여 각 DNA sequence의 primer 영역을 찾는 작업을 진행하며, 사용자가 직접 프로그램을 테스트할 수 있는 웹사이트를 제공한다. 실험 대상으로는 mycoides를 선택하였으며, 이 논문에서 제안된 방법을 사용하여 성공적으로 probe set을 발견할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.43-46
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• 2003

In this paper, a novel rotor flux estimation method of an induction motor using support vector machine(SVM) is presented. Two veil-known different flux models with respect to voltage and current are necessary to estimate the rotor flux of an induction motor. The theory of the SVM algorithm is based on statistical teaming theory. Training of SVH leads to a quadratic programming(QP) problem. The proposed SVM rotor flux estimator guarantees the improvement of performance in the transient and steady state in spite of parameter variation circumstance. The validity and the usefulness of Proposed algorithm are throughly verified through numerical simulation.