• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.49-52
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• 2002

A new method is developed to extract model parameters of SiGe HBT equivalent circuit including the base impedance and base-collector junction capacitance. Using this method, all resistances and capacitances of SiGe HBT are independently determined from measured S-parameters using two-port parameter formula. This method is proposed to reduce possible errors generated from global optimization process, and its accuracy has been verified by finding good agreements between measured and modeled current / power gain up to 18 GHz.

• Korean Management Science Review
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• v.32 no.2
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• pp.69-78
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• 2015

This paper considers a Bayesian Poisson model for multivariate count data using multiplicative rates. More specifically we compose the parameter for overall arrival rates by the product of two parameters, a common effect and an individual effect. The common effect is composed of autoregressive evolution of the parameter, which allows for analysis on seasonal effects on all multivariate time series. In addition, analysis on individual effects allows the researcher to differentiate the time series by whatevercharacterization of their choice. This type of model allows the researcher to specifically analyze two different forms of effects separately and produce a more robust result. We illustrate a simple MCMC generation combined with a Gibbs sampler step in estimating the posterior joint distribution of all parameters in the model. On the whole, the model presented in this study is an intuitive model which may handle complicated problems, and we highlight the properties and possible applications of the model with an example, analyzing real time series data involving customer arrivals to a large retail store.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.117-122
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• 1994

In this paper, we discuss the modeling of flexible manipulators. In the modeling of flexible manipulators, there are two approaches: one is based on the distributed-parameter modeling and the other on the lumped-parameter modeling. The former has been applied to control and analysis of simple manipulator requiring precision, while the latter has been applied to multi-link spatial manipulator, because of the model's simplicity. We have already proposed the lumped-parameter modeling method for simple manipulator, and investigate that model of how much degree of precision we can get. The experiments and simulations are performed, comparing these results, the approximate performance of our modeling method is discussed.

• Journal of KSNVE
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• v.9 no.3
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• pp.525-534
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• 1999

The present paper proposes a generalized modal analysis procedure for non-uniform, distributed-parameter rotor-bearing systems. An exact element matrix is derived for a Timoshenko shaft model which contains rotary inertia, shear deformation, gyroscopic effect and internal damping. Complex coordinates system is adopted for the convenience in formulation. A generalized orthogonality condition is provided to make the modal decomposition possible. The generalized modal analysis by using a modal decomposition delivers exact and closed form solutions both for frequency and time responses. Two numerical examples are presented for illustrating the proposed method. The numerical study proves that the proposed method is very efficient and useful for the analysis of distributed-parameter rotor-bearing systems.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.93-102
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• 2021

This study aimed to test method on the accuracy of estimating the items parameters and ability, using the Three Parameter Logistic. To achieve the objectives of the study, an achievement test in chemistry was constructed for third-year secondary school students in the course of "natural sciences". A descriptive approach was employed to conduct the study. The test was applied to a sample of (507) students of the third year of secondary school in the "Natural Sciences Course". The study's results revealed that the (EAP) method showed a higher degree of accuracy in the estimation of the difficulty parameter and the abilities of persons higher than the MML method. There were no statistically significant differences in the accuracy of the parameter estimation of discrimination and guessing regarding the difference of the two methods: (MML) and (EAP).

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.313-335
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• 1995

Suppose that we have $k(k \geq 2)$ populations (or systems), say $\pi_1, \cdots, \pi_k$, to be tested. Under the type-II censored testing without replacement we consider the problem of estimating the unknown parameters of interests and the reliability for a given time t for each population. Also we compare the perfomances of the proposed Bayes estimators with another estiamtors under the Jeffrey-type noninformative prior distribution.

• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.101-113
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• 2001

The main purpose of this paper is to present deflections of laminated composite plates on the two-parameter foundations. that is an elastic foundation with shear layer. This paper focuses on the deformation behaviour of anisotropic structures on elastic foundations. The third-order shear deformation theory is applied by using the double-fourier series. To validate the derived equations the obtained displacements for simply supported isotropic and orthotropic plates on elastic foundations are compared with those of Timoshenko and LUSAS program. The results show an excellent agreement for the isotropic and LUSAS program. The results show an excellent agreement for the isotropic and orthotropic plates on the elastic foundations. Numerical results for displacements are presented to show the effects of side-to-thickness ratio aspect ratio, material anisotropy and shear modulus of foundations.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.153-156
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• 1999

The technique is reported of identifying parameters in off-line process. The technique demands that closed-loop system consists of a reference and two-degree-of-freedom controllers (TDFC) in real process. A model process is the same as the real process except their parameters. Deviations are differences between the reference and the output of the plant or the model. The technique is based on minimizing identification error between the two deviations. The parameter differences between the plant and the model are characterized of mean value and of variance which are derived from the identification error. Consequently, the algorithm which identifies the unknown plant parameters is shown by minimizing the mean value and the variance, respectively, within double convergence loops. The technique is applied to course change of a ship. The plant deviation at the first trial is shown to occur in replacing the nominal parameters by the default parameters. The plant deviation at the second trial is shown to not occur in replacing the nominal parameters by the identified parameters. Hence, the identification technique is confirmed to be feasible in the real field.

• Journal of the Korean Data and Information Science Society
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• v.25 no.2
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• pp.393-402
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• 2014

The simplest and the most important distribution in survival analysis is the exponential distribution. In this paper, we investigate the influence of the random censorship model on the estimation of the scale parameter of the exponential distribution. The considered random censorship models are Koziol-Green model and the generalized exponential distribution model. Two models have different meanings. Through the simulation study, the averages of the estimated values of the parameter do not show big differences, however the MSE of the estimator tends to be bigger when the supposed model is significantly different from the true model.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.355-359
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• 1993

This paper deals with the problem of robust TDF(Two Degree of Freedom) H$_{\infty}$ control design for a linear system with parameter uncertainty in the state space model. The uncertain system considered here is with the time-invariant norm-bounded parameter uncertainty in the state matrix. A TDF H$_{\infty}$ control design is presented which robustly stabilizes the plant, guarantees the robust H$_{\infty}$ performance and improves the tracking performance for the closed-loop system in the face of parameter uncertainty. It is shwon that a suitable stabilizing control law can be constructed in terms of a positive definite solution to a certain parameter-dependent algebraic Riccati equation and a good tracking performance can be constructed in terms of suitable feedforward control law.aw.