• 대한수학회지
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• 제53권6호
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• pp.1371-1389
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• 2016

In this paper, we propose a new rank two quasi-Newton method based on adjoint Broyden updates for solving symmetric nonlinear equations, which can be seen as a class of adjoint BFGS method. The new rank two quasi-Newton update not only can guarantee that $B_{k+1}$ approximates Jacobian $F^{\prime}(x_{k+1})$ along direction $s_k$ exactly, but also shares some nice properties such as positive deniteness and least change property with BFGS method. Under suitable conditions, the proposed method converges globally and superlinearly. Some preliminary numerical results are reported to show that the proposed method is effective and competitive.

• Journal of applied mathematics & informatics
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• 제41권1호
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• pp.133-154
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• 2023

In this paper, we introduce the concept of tripolar fuzzy sub-semigroups, tripolar fuzzy ideals, tripolar fuzzy quasi-ideals, and tripolar fuzzy bi-ideals of an ordered semigroup and study some algebraic properties of them. Moreover, we prove that tripolar fuzzy bi-ideals and quasi-ideals coincide only in a particular class of ordered semigroups. Finally, we prove that every tripolar fuzzy quasi-ideal is the intersection of a tripolar fuzzy left and a tripolar fuzzy right ideal.

• 대한수학회논문집
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• 제32권1호
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• pp.39-46
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• 2017

In this paper, we propose a new multistep iteration for a finite family of asymptotically quasi-nonexpansive mappings in convex cone metric spaces. Then we show that our iteration converges to a common fixed point of this class of mappings under suitable conditions. Our result generalizes the corresponding result of Lee [5] from the closed convex subset of a convex cone metric space to whole space.

• 호남수학학술지
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• 제41권1호
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• pp.35-49
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• 2019

In this work, it is shown that the combination of operational techniques and the use of the principle of quasi-monomiality can be a very useful tool for a more general insight into the theory of matrix polynomials and for their extension. We explore the formal properties of the operational rules to derive a number of properties of certain class of matrix polynomials and discuss the operational links with various known matrix polynomials.

• Journal of applied mathematics & informatics
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• 제7권1호
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• pp.101-113
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• 2000

In this paper, we introduce and study a new class of variational inclusions, called the set-valued quasi variational inclusions. The resolvent operator technique is used to establish the equivalence between the set-valued variational inclusions and the fixed point problem. This equivalence is used to study the existence of a solution and to suggest a number of iterative algorithms for solving the set-valued variational inclusions. We also study the convergence criteria of these algorithms.

• Journal of Information Processing Systems
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• 제14권4호
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• pp.851-876
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• 2018

Dynamic time warping (DTW) is the main algorithms for time series alignment. However, it is unsuitable for quasi-periodic time series. In the current situation, except the recently published the shape exchange algorithm (SEA) method and its derivatives, no other technique is able to handle alignment of this type of very complex time series. In this work, we propose a novel algorithm that combines the advantages of the SEA and the DTW methods. Our main contribution consists in the elevation of the DTW power of alignment from the lowest level (Class A, non-periodic time series) to the highest level (Class C, multiple-periods time series containing different number of periods each), according to the recent classification of time series alignment methods proposed by Boucheham (Int J Mach Learn Cybern, vol. 4, no. 5, pp. 537-550, 2013). The new method (quasi-periodic dynamic time warping [QP-DTW]) was compared to both SEA and DTW methods on electrocardiogram (ECG) time series, selected from the Massachusetts Institute of Technology - Beth Israel Hospital (MIT-BIH) public database and from the PTB Diagnostic ECG Database. Results show that the proposed algorithm is more effective than DTW and SEA in terms of alignment accuracy on both qualitative and quantitative levels. Therefore, QP-DTW would potentially be more suitable for many applications related to time series (e.g., data mining, pattern recognition, search/retrieval, motif discovery, classification, etc.).

• 충청수학회지
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• 제27권2호
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• pp.183-203
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• 2014

We examine fundamental units of quadratic function fields from continued fraction of $\sqrt{D}$. As a consequence, we give another proof of geometric analog of Ankeny-Artin-Chowla-Mordell conjecture and bounds for class number, and study real quadratic function fields of minimal type with quasi-period 4.

• 한국전자파학회논문지
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• 제21권1호
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• pp.61-68
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• 2010

본 논문에서는 접지 결함 구조(Defected Ground Structure: DGS)를 이용하여 기지국용 고효율 E급 전력 증폭기의 성능을 유지하면서 크기를 소형화 할 수 있는 방안을 제안하였다. E급 전력 증폭기에서 요구되는 고조파 임피던스는 아령형 DGS와 나선형 DGS를 사용함으로써 만족시켜 주었다. 제안하는 유사 E급 전력 증폭기의 DGS 부하 회로는 가장 큰 고조파 성분인 2차 고조파 대역에서 개방, 나머지 고차 고조파 임피던스는 단락에 가까운 고조파 임피던스를 갖는다. 제안하는 구조를 통하여 제작된 전력 증폭기는 출력 전력이 43.1 dBm, 포화전력 이득이 12.7 dB일 때 70.2 %의 전력 부가 효율(Power Added Efficiency: PAE)을 가지며, 이는 비교 대상인 E급 증폭기와 거의 유사한 값이다. 회로 크기의 관점에서 보면 각각의 고조파 성분 정합을 위해 여러 개의 스터브가 장착되어 있는 비교 대상인 E급 증폭기에 비해 전체 크기를 50 %로 소형화시킬 수 있었다.

• Communications for Statistical Applications and Methods
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• 제18권4호
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• pp.477-483
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• 2011

This article is concerned with a class of threshold-asymmetric GARCH models both for stationary case and for non-stationary case. We investigate large sample properties of estimators from QML(quasi-maximum likelihood) and QL(quasilikelihood) methods. Asymptotic distributions are derived and it is interesting to note for non-stationary case that both QML and QL give asymptotic normal distributions.

• ETRI Journal
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• 제33권3호
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• pp.393-400
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• 2011

A systematic approach for the design of two-stage class AB CMOS unity-gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity-gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three design examples are fabricated in a 0.5 ${\mu}m$ CMOS process. Measurement results show slew rate improvement factors of approximately 100 for the class AB buffers versus their class A counterparts for the same quiescent power consumption (< 200 ${\mu}W$).