• Journal of the Korean Data and Information Science Society
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• 제21권2호
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• pp.291-296
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• 2010

In this paper, we consider a versatile test based on percentile tests. The versatile test may be useful when the underlying distributions are unknown or quite different types. We consider two kinds of combining functions for the percentile statistics, the quadratic and summing forms and obtain the limiting distributions under the null hypothesis. Then we illustrate our procedure with an example. Finally we discuss some interesting features of the test as concluding remarks.

• 대한수학회보
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• 제56권3호
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• pp.779-787
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• 2019

In this paper, we study two functional equations with two unknown functions from an Abelian group into a commutative ring without zero divisors. The two equations are generalizations of Swiatak's functional equations with an involution. We determine the general solutions of the two functional equations and the properties of the general solutions of the two functional equations under three different hypotheses, respectively. For one of the functional equations, we establish the Hyers-Ulam stability in the case that the unknown functions are complex valued.

• 대한수학회지
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• 제60권2호
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• pp.395-406
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• 2023

As an analogy of the Rogers-Ramanujan continued fraction, we define a Ramanujan continued fraction of order eighteen. There are essentially three Ramanujan continued fractions of order eighteen, and we study them using the theory of modular functions. First, we prove that they are modular functions and find the relations with the Ramanujan cubic continued fraction C(𝜏). We can then obtain that their values are algebraic numbers. Finally, we evaluate them at some imaginary quadratic quantities.

• Membrane and Water Treatment
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• 제9권5호
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• pp.363-371
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• 2018

In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.

• 전기학회논문지
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• 제57권11호
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• pp.2108-2116
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• 2008

The paper concerns Fuzzy C-Means clustering based Radial Basis Function neural networks (FCM-RBFNN) and the optimization of the network is carried out by means of Particle Swarm Optimization(PSO). FCM-RBFNN is the extended architecture of Radial Basis Function Neural Network(RBFNN). In the proposed network, the membership functions of the premise part of fuzzy rules do not assume any explicit functional forms such as Gaussian, ellipsoidal, triangular, etc., so its resulting fitness values directly rely on the computation of the relevant distance between data points by means of FCM. Also, as the consequent part of fuzzy rules extracted by the FCM - RBFNN model, the order of four types of polynomials can be considered such as constant, linear, quadratic and modified quadratic. Weighted Least Square Estimator(WLSE) are used to estimates the coefficients of polynomial. Since the performance of FCM-RBFNN is affected by some parameters of FCM-RBFNN such as a specific subset of input variables, fuzzification coefficient of FCM, the number of rules and the order of polynomials of consequent part of fuzzy rule, we need the structural as well as parametric optimization of the network. In this study, the PSO is exploited to carry out the structural as well as parametric optimization of FCM-RBFNN. Moreover The proposed model is demonstrated with the use of numerical example and gas furnace data set.

• 응용통계연구
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• 제20권1호
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• pp.103-115
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• 2007

본 논문에서는 1차 자기회귀모형에서 자기회귀계수에 대한 여러 가지 추정량들의 분포함수에 대한 근사 방법에 대해 연구하였다. 자기회귀계수의 여러 추정량들을 이차형식의 관점에서 이해하고, Na와 Kim(2005)에 의한 안장점근사의 결과를 이용한 새로운 근사법을 제시하였다. 이 방법은 정규근사를 비롯한 기존의 근사법과는 달리 추정량에 대한 근사분포의 유도과정이 불필요하며, 소표본은 물론 통계적 추론의 주요 관심영역에서의 근사정도가 매우 뛰어난 장점을 가지고 있다. 모의실험을 통해 Edgeworth 근사를 비롯한 기존의 여러 근사법보다 효율이 뛰어남을 확인하였다.

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.506-514
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• 2008

This paper presents an intelligent model; named as free model, approach for a closed-loop system identification using input and output data and its application to design a power system stabilizer (PSS). The free model concept is introduced as an alternative intelligent system technique to design a controller for such dynamic system, which is complex, difficult to know, or unknown, with input and output data only, and it does not require the detail knowledge of mathematical model for the system. In the free model, the data used has incremental forms using backward difference operators. The parameters of the free model can be obtained by simultaneous perturbation stochastic approximation (SPSA) method. A linear transformation is introduced to convert the free model into a linear model so that a conventional linear controller design method can be applied. In this paper, the feasibility of the proposed method is demonstrated in a one-machine infinite bus power system. The linear quadratic regulator (LQR) method is applied to the free model to design a PSS for the system, and compared with the conventional PSS. The proposed SPSA-based LQR controller is robust in different loading conditions and system failures such as the outage of a major transmission line or a three phase to ground fault which causes the change of the system structure.

• Journal of the Korean Data and Information Science Society
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• 제25권3호
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• pp.547-554
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• 2014

본 논문은 실험자료에 대한 분석모형으로 이원 분산분석모형을 가정한다. 확률효과 모형의 가정하에 분산성분의 추정량을 구하기 위한 방법으로 적률법을 가정하고 있다. 분산성분의 적률 추정방법인 Henderson의 방법 I과 방법 III을 다루고 있다. Henderson의 두 방법에서 소개되는 제곱합 대신에 벡터공간에서의 사영을 활용하는 방법을 제시하고 있다. 또한 제곱합의 기대값 계산을 위해 두 방법 모두 Hartley의 합성법을 제공하고 있으나 본 논문에서는 관련행렬의 고유근을 이용할 수 있음을 제시하고 있다. 분산성분의 해를 얻기 위한 방법의 차이에서 유도되는 연립방정식들은 같지 않으나 양수의 분산성분들에 대한 해는 유사함을 보여주고 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권5호
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• pp.577-582
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• 1996

In order to investigate the relationship between daily herbage allowance (DHA) and daily herbage intake (DHI) on the points of leaf and stem masses, grazing experiments were carried out on the pasture of tall fescue (Festuca arundinacea Schreb.). The experiments consisted of four 3-days' grazing periods which were from August 14 to 17, August 17 to 20, October 12 to 15 and October 15 to 18 in 1990. The value of DHA was 32.1 to 84.3, and the value of DHI was 9.9 to 27.0. The index of leafiness (leaf to stem ratio, LSR) was 0.74 to 3.06. The relationship between DHI and DHA was quadratic. Both relationship of daily leaf intake (DLI) to daily leaf allowance (DLA) and that of daily stem intake (DSI) to daily stem allowance (DSA) were likely to be asymptotic forms, although DHI did not show any significant relationships to DLA nor to DSA. The relationship between DLI and LSR was quadratic, and a negative relationship was found between DSI and LSR. From the relationship of DLI to LSR and that of DSI to LSR, the relationship of daily intake of leaf and stem (DLSI) to LSR was derived as quadratic and the LSR value at which the maximum DLSI was attained was estimated. The DHA, DHI, DLA, DLI, DSA, DSI and DLAI were expressed as the same unit of g/kg live body weight/day.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.700-705
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• 2005

The purpose of this project is the derivation and development of techniques for the new estimation of robustness for the systems having uncertainties. The basic ideas to analyze the system which is the originally nonlinear is Lyapunov direct theorems. The nonlinear systems have various forms of terms inside the system equations and this investigation is confined in the form of bounded uncertainties. Bounded means the uncertainties are with same positive/negative range. The number of uncertainties will be the degree of freedoms in the calculation of the stability region. This is so called the robustness bounds. This proposition adopts the theoretical analysis of the Lyapunov direct methods, that is, the sign properties of the Lyapunov function derivative integrated along finite intervals of time, in place of the original method of the sign properties of the time derivative of the Lyapunov function itself. This is the new sufficient criteria to relax the stability condition and is used to generate techniques for the robust design of control systems with structured perturbations. Using this relaxing stability conditions, the selection of Lyapunov candidate function is of various forms. In this paper, the quadratic form is selected. this generated techniques has been demonstrated by recent research interest in the area of robust control design and confirms that estimation of robustness bounds will be improved upon those obtained by results of the original Lyapunov method. In this paper, the symbolic algebraic procedures are utilized and the calculating errors are reduced in the numerical procedures. The application of numerical procedures can prove the improvements in estimations of robustness for one-and more structured perturbations. The applicable systems is assumed to be linear with time-varying with nonlinear bounded perturbations. This new techniques will be extended to other nonlinear systems with various forms of uncertainties, especially in the nonlinear case of the unstructured perturbations and also with various control method.