• 전기학회논문지
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• 제62권1호
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• pp.133-139
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• 2013

Convex combination of two adaptive filters is an efficient method to improve adaptive filter performances. In this paper, a subband convex combination method of two adaptive filters for fast convergence rate in the transient state and low steady state error is presented. The cost function of mixing parameter for a subband convex combination is defined, and from this, the coefficient update equation is derived. Steady state analysis is used to prove the stability of the subband convex combination. Some simulation examples in system identification scenario show the validity of the subband convex combination schemes.

• 한국항행학회논문지
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• 제20권3호
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• pp.203-209
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• 2016

자동종속 감시 시스템 (ADS-B; automatic dependent surveillance - broadcast) 시스템과 다변측정 항공감시 시스템(MLAT, multilateration) 시스템은 통신/항행/감시 및 교통관리 (CNS/ATM; communications, navigation, and surveillance/air traffic management)의 다양한 분야 중에서 감시분야에 속한다. ADS-B와 MLAT는 위성 및 디지털 통신 기술을 기반으로 구현되어 레이더 보다 성능이 뛰어나지만, 여전히 오차는 가지고 있다. 우는 이러한 오차를 줄이기 위해 reweighted convex combination method를 제안한다. Reweighted convex combination method는 기존의 convex combination method를 개선한 정보융합 기법으로 시스템에 주어지는 가중치를 재조정하여 항공기 추적 성능을 향상시킨다. reweighted convex combination method을 ADS-B와 MLAT에 적용 시켰을 때, 평균 51.51 %의 성능향상이 있었다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.72-77
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• 2017

This paper proposes the explicit tuning rule of multi-loop PID controller for brushless direct current motors to predict the system behaviors in time and frequency domains, using properties of the convex combination method. The convex set of the proposed controllers formulates the envelope to satisfy the performances in time and frequency domains. The final control parameters are determined by solving the convex optimization problem subject to the constraints which are represented as convex set of time domain performances. The effectiveness of the proposed control method is shown in the numerical simulation, in which controller tuning algorithm and dynamics of brushless DC motor are well taken into account.

• 대한수학회보
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• 제41권4호
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• pp.641-646
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• 2004

A convex combination of two products with same degree of finitely many finite geometric series with each having even degree does not always have all its zeros on the unit circle. However, in this paper, we show that a polynomial obtained by just adding a finite geometric series multiplied by a large constant to such a convex combination has all its zeros on the unit circle.

• Journal of the Korean Statistical Society
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• 제28권1호
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• pp.57-72
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• 1999

Falk(1994) showed that the asymptotic efficiency of the Pickands estimator of the extreme value index $\beta$ can considerably be improved by a simple convex combination. In this paper we propose an alternative estimator of $\beta$ which is as asymptotically efficient as the optimal convex combination of the Pickands estimators but has a better finite-sample performance. We prove consistency and asymptotic normality of the proposed estimator. Monte Carlo simulations are conducted to compare the finite-sample performances of the proposed estimator and the optimal convex combination estimator.

• Communications for Statistical Applications and Methods
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• 제13권2호
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• pp.379-387
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• 2006

Local polynomial regression is widely used because of good properties such as such as the adaptation to various types of designs, the absence of boundary effects and minimax efficiency Choi and Hall (1998) proposed an estimator of regression function using a convex combination idea. They showed that a convex combination of three local linear estimators produces an estimator which has the same order of bias as a local cubic smoother. In this paper we suggest another estimator of regression function based on a convex combination of five local constant estimates. It turned out that this estimator has the same order of bias as a local cubic smoother.

• Nonlinear Functional Analysis and Applications
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• 제27권3호
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• pp.621-640
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• 2022

The aim of this study is to establish some mean convergence theorems for double array of fuzzy random variables in metric space endowed with a convex combination operation under various assumptions.

• 한국정보통신학회논문지
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• 제12권8호
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• pp.1377-1383
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• 2008

3차원 메쉬 매개변수화는 기하학적 모델링과 컴퓨터그래픽스의 여러 응용분야에서 핵심적인 문제이다. 메쉬 매개변수화 방법에는 크게 두 가지의 패러다임, 에너지 최소화 방법과 볼록 조합법이 있다. 일반적으로 볼록 조합법은 간단한 개념과 일대일 대응 때문에 널리 이용되고 있다. 그러나 이 방법은 경계선 근처의 높은 왜곡이 생긴다는 문제와 선형 시스템 구성에 있어 다소 많은 시간이 소요되는 문제를 가지고 있다. 또한 이 방법은 다루는 메쉬 의 기하학 정보에 따라 선형시스템의 안정성이 해손 될 수도 있다. 본 논문에서는 볼록 조합법이 갖고 있는 선형시스템 안정성 문제와 시간 복잡도 문제를 중간값 좌표계를 이용하여 해결한다. 빠른 시간에 안정적으로 처리가 가능하기 때문에 보다 실용적이라 할 수 있다.

• Journal of information and communication convergence engineering
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• 제2권3호
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• pp.193-197
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• 2004

In this paper, a combination problem of controllers which are the same type of $H_{\infty}$ controllers designed with different weighting functions. This approach can remove the difficulty in the selection of the weighting functions. As a sub-controller, the Youla type of $H_{\infty}$ controller is used. In the $H_{\infty}$ controller, Youla parameterization is used to minimize $H_{\infty}$ norm of mixed sensitivity function by using polynomial approach. Computer simulation results show the robustness improvement and the performance improvement.

• Kyungpook Mathematical Journal
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• 제54권4호
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• pp.521-529
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• 2014

In this paper we derive some optimal convex combination bounds related to arithmetic mean. We find the greatest values ${\alpha}_1$ and ${\alpha}_2$ and the least values ${\beta}_1$ and ${\beta}_2$ such that the double inequalities $${\alpha}_1T(a,b)+(1-{\alpha}_1)H(a,b)<A(a,b)<{\beta}_1T(a,b)+(1-{\beta}_1)H(a,b)$$ and $${\alpha}_2T(a,b)+(1-{\alpha}_2)G(a,b)<A(a,b)<{\beta}_2T(a,b)+(1-{\beta}_2)G(a,b)$$ holds for all a,b > 0 with $a{\neq}b$. Here T(a,b), H(a,b), A(a,b) and G(a,b) denote the second Seiffert, harmonic, arithmetic and geometric means of two positive numbers a and b, respectively.