• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.137-140
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• 2001

In this paper, we design 75(Takagi-Sugeno) fuzzy controllers for the systems that can be represented by the 75 fuzzy model. We use inverse optimal approach in which the cost function is determined later than the Lyapunov function and its corresponding control input satisfying the design requirements such as stability and decay rate. The obtained design procedure is in the form of solving LMI(Linear Matrix Inequalities), thus very efficient in practice.

• 대한인간공학회지
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• 제6권1호
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• pp.3-8
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• 1987

This paper develops a statistical mode which estimates mental and physical loads of light work from sinus arrhythmia (SA) scores. During experiments, various levels of mental and physical loads (respectively scored by information processing and finger tapping rates) were imposed on subjects and SA scores were measured from the subjects. Two methods were used in developing workload estimation model. One is an algebraic inverse function of a multivariate regression equation, where mental and physical loads are independent variables and SA scores are dependent variables. The other is a statistical multivariate inverse regression. Of the two methods, inverse function resulted in larger mean squqre error in predicting mental and physical loads. Hence, inverse regression model is recommended for precise workload estimation.

• 한국통신학회논문지
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• 제21권5호
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• pp.1317-1324
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• 1996

An angular spectral inverse technique, applying the moment method procedure with a series expansion for the induced field in each enlarged cell, is suggested to reconstruct permittivity profiles of inhomogeneous dielectric objects and to reduce the ill-posedness inherent to inverse scattering problems. The angular spectral inverse scattering using the pulse basis function in enlarging the scatterer has the ill-posedness due to the input data of higher spectra. To reduce the number of higher spectra, enlarging the cell size and averaging over the cell with a suitable weighting function are found to play improtant roles for the reduction of ill-posedness of the angular spectral inverse scattering problems.

• 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.315-318
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• 1995

The optimum design problem of a coat-hanger die is solved by the inverse formulation. The flow in the die is analyzed using three-dimensional model. The new model for the manifold geometry is developed for the inverse formulation. The inverse problem for the optimum die geometry is formed as the optimization problem whose objective function is the linear combination of the square sum of pressure gradient deviation at die exit and the penalty function relating to the measure of non-smoothness of solution. From the several iterative solutions of the optimization problem, the optimum solution can be obtained automatically while producing the uniform flow rate distribution at die exit.

• 한국수학교육학회지시리즈A:수학교육
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• 제58권2호
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• pp.239-262
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• 2019

본 연구에서는 특정한 학생의 질문에서 시작된 고민을 다루고 있으며, 교과서 분석을 통하여 해당 질문이 충분히 제기 가능한 질문임을 확인하였다. 또한 면담을 거쳐 두 대응관계가 연결된 새로운 대응관계에서 학생들이 합성함수 여부 판정과 역함수 존재 여부 판정에서 정의역에 대한 고민이 학생들에게서 어떻게 의미 있는 수학 지식으로 재구성 되어가는 지에 대한 사례를 관찰하였다. 본 연구에서 제시된 사례들은 제한된 상황에서의 특정한 사례라는 한계가 있기 때문에 곧바로 교수학습 상황에 적용될 수는 없으나 다른 연구자들에게 함수 학습 관련 연구에 대하여 통찰의 기회를 제공할 수 있을 것으로 기대된다.

• Communications for Statistical Applications and Methods
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• 제27권4호
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• pp.469-486
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• 2020

Entropy is an important term in statistical mechanics that was originally defined in the second law of thermodynamics. In this paper, we consider the maximum likelihood estimation (MLE), maximum product spacings estimation (MPSE) and Bayesian estimation of the entropy of an inverse Weibull distribution (InW) under a generalized type I progressive hybrid censoring scheme (GePH). The MLE and MPSE of the entropy cannot be obtained in closed form; therefore, we propose using the Newton-Raphson algorithm to solve it. Further, the Bayesian estimators for the entropy of InW based on squared error loss function (SqL), precautionary loss function (PrL), general entropy loss function (GeL) and linex loss function (LiL) are derived. In addition, we derive the Lindley's approximate method (LiA) of the Bayesian estimates. Monte Carlo simulations are conducted to compare the results among MLE, MPSE, and Bayesian estimators. A real data set based on the GePH is also analyzed for illustrative purposes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4567-4583
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• 2021

This study proposes an analytical approximation algorithm based on extreme value theory (EVT) for the inverse of the power of the incomplete Gamma function. First, the Gumbel function is used to approximate the power of the incomplete Gamma function, and the corresponding inverse problem is transformed into the inversion of an exponential function. Then, using the tail equivalence theorem, the normalized coefficient of the general Weibull distribution function is employed to replace the normalized coefficient of the random variable following a Gamma distribution, and the approximate closed form solution is obtained. The effects of equation parameters on the algorithm performance are evaluated through simulation analysis under various conditions, and the performance of this algorithm is compared to those of the Newton iterative algorithm and other existing approximate analytical algorithms. The proposed algorithm exhibits good approximation performance under appropriate parameter settings. Finally, the performance of this method is evaluated by calculating the thresholds of space-time block coding and space-frequency block coding pattern recognition in multiple-input and multiple-output orthogonal frequency division multiplexing. The analytical approximation method can be applied to other related situations involving the maximum statistics of independent and identically distributed random variables following Gamma distributions.

• 한국학교수학회논문집
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• 제23권1호
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• pp.67-88
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• 2020

여러 국외 연구는 SMK의 주요 특징을 HCK와 관련하여 설명하면서 수학 교사 교육의 핵심 목표 중 하나로 HCK의 개발을 강조하였다. 그러나 국내에는 SMK의 하위 요소로서 HCK의 구체적인 의미를 살피거나 우리나라 교사들이 지닌 HCK의 특징을 본격적으로 분석한 연구가 거의 없다. 이에 이 연구는 Ball & Bass(2009)의 관점에서 HCK를 다룬 국외 연구를 검토하여 대학 수학을 통해 개발될 필요가 있는 HCK의 특징을 구체적으로 확인하였다. 또한 대학 수학의 목표가 AMT 개발에 있음을 강조한 Zazkis & Leikin(2010)에 따라 AMT 관련 선행 연구를 분석하여 HCK 개발의 기반이 되는 AMT의 핵심 특징을 구체화하였다. 이를 토대로 예비교사들의 HCK를 역함수 기호에 대한 이해에 주목하여 분석하기 위한 지필 검사 도구를 개발하였으며, 이를 예비교사 57명에게 적용하여 얻은 답변 자료를 검사 도구 개발 의도 및 함수 개념 수준에 비추어 분석하였다. 이로부터 역함수 및 역함수 기호와 관련하여 예비교사들이 지닌 HCK의 특징을 4가지로 추출하였으며, 각각의 특징이 지닌 시사점을 수학 교사 전문성 신장을 위한 HCK 개발의 측면에서 기술하였다.

• Communications for Statistical Applications and Methods
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• 제19권3호
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• pp.479-493
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• 2012

The inverse Weibull distribution(IWD) is a complementary Weibull distribution and plays an important role in many application areas. In this paper, we develop a Bayesian estimator in the context of record statistics values from the exponentiated inverse Weibull distribution(EIWD). We obtained Bayesian estimators through the squared error loss function (quadratic loss) and LINEX loss function. This is done with respect to the conjugate priors for shape and scale parameters. The results may be of interest especially when only record values are stored.

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.710-719
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• 2002

This study investigates a nonlinear inverse convection problem for a laminar-forced convective flow between two parallel plates. The upper plate is exposed to unknown heat flux while the lower plate is insulated. The unknown heat flux is determined using temperature measured on the lower plate. The thermophysical properties of the fluid are temperature dependent, which renders the problem nonlinear. The sequential gradient method is applied to this nonlinear inverse problem in order to solve the problem efficiently. The function specification method is incorporated to stabilize the sequential estimation. The corresponding adjoint formalism is provided. Accuracy and stability have been examined for the proposed method with test cases. The tendency of deterministic error is investigated for several parameters. Stable solutions are achieved eve]1 with severely impaired measurement data.