• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.75-83
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• 2020

We consider the D2D utility optimization problem in the cellular system. More specifically, we develop a concave function decision rule which reduces the complexity of non-convex optimization problem. Typically, utility function, which is a function of the signal and the interference, is non-convex. In this paper, we analyze the utility function from the interference perspective. We introduce the 'relative interference' and the 'interference majorization'. The relative interference captures the level of interference at D2D receiver's perspective. The interference majorization approximates the interference by applying the major interference. Accordingly, we propose a concave function decision rule, and the corresponding convex optimization solution. Simulation results show that the utility function is concave when the relative interference is less than 0.1, which is a typical D2D usage scenario. We also show that the proposed convex optimization solution can be applied for such relative interference cases.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1456-1459
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• 1997

In this paper, a control system using robust H.inf. controller based on convex parametrization is presented for nonlinear system with uncertainty. accounting for the time delay, noise and linearization error by frequency analysis, the suboptmal controller is designed to meet robust stability and performance for uncertainty. The desinged control system is applied to a nonlimear boiler moderl to test its performances.

• Nonlinear Functional Analysis and Applications
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• v.26 no.1
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• pp.93-104
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• 2021

In this paper, we present a fixed point theorem for a family of generalized condensing multimaps which have ranges of the Zima-Hadžić type in Hausdorff KKM uniform spaces. It extends Himmelberg et al. type fixed point theorem. As applications, we obtain some new collective fixed point theorems for various type generalized condensing multimaps in abstract convex uniform spaces.

• Nonlinear Functional Analysis and Applications
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• v.26 no.3
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• pp.601-610
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• 2021

A convergence theorem for a generalized 𝜑-weakly contractive mapping is proved which satisfy a generalized contraction condition on a complete metrically convex metric space. The result in this paper generalizes the relevant results due to Rhoades [18], Alber and Guerre-Delabriere [1], Khan and Imdad [14], Xue [20] and others. An illustrative example is also furnished in support of our main result.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.81-82
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• 2020

Non-convex 최적화 문제의 복잡도를 완화하도록 해주는 오목함수 결정규칙을 제안한다. 전송용량을 나타내는 유틸리티 함수는 신호와 간섭의 함수이며, non-convex이다. 유틸리티 함수를 간섭관점에서 분석한다. '상대간섭'과 '간섭주요화'를 정의한다. 상대간섭은 D2D 수신단에서의 간섭레벨을 나타낸다. 간섭주요화는 간섭을 주요간섭으로 간략화한다. 간섭주요화를 기반으로 하는 오목함수 결정규칙을 제안한다. 실험결과를 통하여 유틸리티 함수는 상대간섭 0.1 이하에서는 오목함수임을 확인하였다.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.61-68
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• 1996

In this paper we propose a new visualization technique to characterize qualitative information of a large DNA sequence. While a long DNA sequence has huge information, it is not easy to obtain genetic information from the DNA sequence. We transform DNA sequences into a polygon to compute their homology in image domain rather than text domain. Our program visualizes DNA sequences with colored random walk plots and simplify them k-convex hulls. A random walk plot represents DNA sequence as a curve in a plane. A k-convex hull simplifies a random work plot by removing some parts of its insignificant information. This technique gives a biologist an insight to detect and classify DNA sequences with easy. Experiments with real genome data proves our approach gives a good visual forms for long DNA sequences for homology analysis.

• Nonlinear Functional Analysis and Applications
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• v.27 no.3
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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.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1417-1426
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• 2017

Power system analysis, Non-Convex Economic Dispatch (NED) is considered as an open and demanding optimization problem. Despite the fact that realistic ED problems have non-convex cost functions with equality and inequality constraints, conventional search methods have not been able to effectively find the global answers. Considering the great potential of meta-heuristic optimization techniques, many researchers have started applying these techniques in order to solve NED problems. In this paper, a new and efficient approach is proposed based on imperialist competitive algorithm (ICA). The proposed algorithm which is named multi-operator ICA (MuICA) merges three operators with the original ICA in order to simultaneously avoid the premature convergence and achieve the global optimum answer. In this study, the proposed algorithm has been applied to different test systems and the results have been compared with other optimization methods, tending to study the performance of the MuICA. Simulation results are the confirmation of superior performance of MuICA in solving NED problems.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.567-574
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• 2018

Let $f:f(z)=z+{\sum^{{\infty}}_{n=2}}a_nz^n$ be analytic in the open unit disc E. Then f is said to belong to the class $M_{\alpha}$ of alpha-convex functions, if it satisfies the condition ${\Re}\{(1-{{\alpha})}{\frac{zf^{\prime}(z)}{f(z)}}+{{\alpha}}{\frac{(zf^{\prime}(z))^{\prime})}{f^{\prime}(z)}}\}$ > 0, ($z{\in}E$). In this paper, we introduce and study q-analogue of the class $M_{\alpha}$ by using concepts of Quantum Analysis. It is shown that the functions in this new class $M(q,{\alpha})$ are q-starlike. A problem related to q-Bernardi operator is also investigated.

• Nonlinear Functional Analysis and Applications
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• v.26 no.1
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• pp.117-135
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• 2021

Our purpose in this paper is to introduce the concept of complex valued convex metric spaces and introduce an analogue of the Picard-Ishikawa hybrid iterative scheme, recently proposed by Okeke [24] in this new setting. We approximate (common) fixed points of certain contractive conditions through these two new concepts and obtain several corollaries. We prove that the Picard-Ishikawa hybrid iterative scheme [24] converges faster than all of Mann, Ishikawa and Noor [23] iterative schemes in complex valued convex metric spaces. Also, we give some numerical examples to validate our results.