• 제목/요약/키워드: Well-posed

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A note on SVM estimators in RKHS for the deconvolution problem

  • Lee, Sungho
    • Communications for Statistical Applications and Methods
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    • v.23 no.1
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    • pp.71-83
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    • 2016
  • In this paper we discuss a deconvolution density estimator obtained using the support vector machines (SVM) and Tikhonov's regularization method solving ill-posed problems in reproducing kernel Hilbert space (RKHS). A remarkable property of SVM is that the SVM leads to sparse solutions, but the support vector deconvolution density estimator does not preserve sparsity as well as we expected. Thus, in section 3, we propose another support vector deconvolution estimator (method II) which leads to a very sparse solution. The performance of the deconvolution density estimators based on the support vector method is compared with the classical kernel deconvolution density estimator for important cases of Gaussian and Laplacian measurement error by means of a simulation study. In the case of Gaussian error, the proposed support vector deconvolution estimator shows the same performance as the classical kernel deconvolution density estimator.

The Study on the Structure of Korean Digital Map (한국형 전자지도 구조에 관한 연구)

  • 윤재경;하동우;우창헌;김수용
    • Spatial Information Research
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    • v.2 no.2
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    • pp.207-218
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    • 1994
  • To activate the use of GIS, it is required to support a reliable digi-tal map. A digital map could be the base for other forms of maps as well as for direct applications, In this paper, the structure of such a basic map is pro¬posed. The structure is designed on the consideration of generality and classifica¬tion. The map data files are all character files and classification codes are pro¬posed.

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Regularized Multichannel Blind Deconvolution Using Alternating Minimization

  • James, Soniya;Maik, Vivek;Karibassappa, K.;Paik, Joonki
    • IEIE Transactions on Smart Processing and Computing
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    • v.4 no.6
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    • pp.413-421
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    • 2015
  • Regularized Blind Deconvolution is a problem applicable in degraded images in order to bring the original image out of blur. Multichannel blind Deconvolution considered as an optimization problem. Each step in the optimization is considered as variable splitting problem using an algorithm called Alternating Minimization Algorithm. Each Step in the Variable splitting undergoes Augmented Lagrangian method (ALM) / Bregman Iterative method. Regularization is used where an ill posed problem converted into a well posed problem. Two well known regularizers are Tikhonov class and Total Variation (TV) / L2 model. TV can be isotropic and anisotropic, where isotropic for L2 norm and anisotropic for L1 norm. Based on many probabilistic model and Fourier Transforms Image deblurring can be solved. Here in this paper to improve the performance, we have used an adaptive regularization filtering and isotropic TV model Lp norm. Image deblurring is applicable in the areas such as medical image sensing, astrophotography, traffic signal monitoring, remote sensors, case investigation and even images that are taken using a digital camera / mobile cameras.

POSITIVE SOLUTIONS FOR A NONLINEAR MATRIX EQUATION USING FIXED POINT RESULTS IN EXTENDED BRANCIARI b-DISTANCE SPACES

  • Reena, Jain;Hemant Kumar, Nashine;J.K., Kim
    • Nonlinear Functional Analysis and Applications
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    • v.27 no.4
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    • pp.709-730
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    • 2022
  • We consider the nonlinear matrix equation (NMEs) of the form 𝓤 = 𝓠 + Σki=1 𝓐*iℏ(𝓤)𝓐i, where 𝓠 is n × n Hermitian positive definite matrices (HPDS), 𝓐1, 𝓐2, . . . , 𝓐m are n × n matrices, and ~ is a nonlinear self-mappings of the set of all Hermitian matrices which are continuous in the trace norm. We discuss a sufficient condition ensuring the existence of a unique positive definite solution of a given NME and demonstrate this sufficient condition for a NME 𝓤 = 𝓠 + 𝓐*1(𝓤2/900)𝓐1 + 𝓐*2(𝓤2/900)𝓐2 + 𝓐*3(𝓤2/900)𝓐3. In order to do this, we define 𝓕𝓖w-contractive conditions and derive fixed points results based on aforesaid contractive condition for a mapping in extended Branciari b-metric distance followed by two suitable examples. In addition, we introduce weak well-posed property, weak limit shadowing property and generalized Ulam-Hyers stability in the underlying space and related results.

FIXED POINTS AND HOMOTOPY RESULTS FOR ĆIRIĆ-TYPE MULTIVALUED OPERATORS ON A SET WITH TWO METRICS

  • Lazar, Tania;O'Regan, Donal;Petrusel, Adrian
    • Bulletin of the Korean Mathematical Society
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    • v.45 no.1
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    • pp.67-73
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    • 2008
  • The purpose of this paper is to present some fixed point results for nonself multivalued operators on a set with two metrics. In addition, a homotopy result for multivalued operators on a set with two metrics is given. The data dependence and the well-posedness of the fixed point problem are also discussed.

AN IMPROVED GLOBAL WELL-POSEDNESS RESULT FOR THE MODIFIED ZAKHAROV EQUATIONS IN 1-D

  • Soenjaya, Agus L.
    • Communications of the Korean Mathematical Society
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    • v.37 no.3
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    • pp.735-748
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    • 2022
  • The global well-posedness for the fourth-order modified Zakharov equations in 1-D, which is a system of PDE in two variables describing interactions between quantum Langmuir and quantum ionacoustic waves is studied. In this paper, it is proven that the system is globally well-posed in (u, n) ∈ L2 × L2 by making use of Bourgain restriction norm method and L2 conservation law in u, and controlling the growth of n via appropriate estimates in the local theory. In particular, this improves on the well-posedness results for this system in [9] to lower regularity.

STABLE APPROXIMATION OF THE HEAT FLUX IN AN INVERSE HEAT CONDUCTION PROBLEM

  • Alem, Leila;Chorfi, Lahcene
    • Communications of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.1025-1037
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    • 2018
  • We consider an ill-posed problem for the heat equation $u_{xx}=u_t$ in the quarter plane {x > 0, t > 0}. We propose a new method to compute the heat flux $h(t)=u_x(1,t)$ from the boundary temperature g(t) = u(1, t). The operator $g{\mapsto}h=Hg$ is unbounded in $L^2({\mathbb{R}})$, so we approximate h(t) by $h_{\delta}(t)=u_x(1+{\delta},\;t)$, ${\delta}{\rightarrow}0$. When noise is present, the data is $g_{\epsilon}$ leading to a corresponding heat $h_{{\delta},{\epsilon}}$. We obtain an estimate of the error ${\parallel}h-h_{{\delta},{\epsilon}}{\parallel}$, as well as the error when $h_{{\delta},{\epsilon}}$ is approximated by the trapezoidal rule. With an a priori choice rule ${\delta}={\delta}({\epsilon})$ and ${\tau}={\tau}({\epsilon})$, the step size of the trapezoidal rule, the main theorem gives the error of the heat flux as a function of noise level ${\epsilon}$. Numerical examples show that the proposed method is effective and stable.

Face Pose Transformation for Pose Invariant Face Recognition (포즈에 독립적인 얼굴 인식을 위한 얼굴 포즈 변환)

  • Park Hyun-Sun;Park Jong-Il;Kim Whoi-Yul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.570-576
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    • 2005
  • Recognition of posed face is one of the most challenging problems in the field of face recognition. In this paper, as a preprocessing step for recognizing such faces, a method to transform non-frontal face images into frontal face images is proposed. The linear relationship between eigenfaces is utilized to obtain a pose transform matrix. The proposed method is verified with a well-known face recognition algorithm based on PCA/LDA. Compared to the conventional algorithm applied to the original posed face images, our experimental results indicated that the proposed method contributes to improve the recognition rate of such faces by $20\%$.

Adapting to the Unpredictable: Companies' Strategies with Business Continuity in the Pandemic Era

  • Choongik CHOI
    • East Asian Journal of Business Economics (EAJBE)
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    • v.12 no.1
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    • pp.23-33
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    • 2024
  • Purpose: This paper explores the nuanced approaches undertaken by private companies in formulating and implementing business continuity plans (BCPs) in response to the unprecedented challenges posed by the global COVID-19 pandemic. Research design, data, and methodology: Utilizing a mixed-methods research design, the study delves into the multifaceted strategies employed by private sector entities, ranging from risk assessment and remote work policies to supply chain diversification and employee well-being initiatives. Result: The findings contribute to a deeper understanding of the evolving landscape of business continuity planning during a pandemic, offering valuable insights for academia, industry practitioners, and policymakers. The research findings present a detailed account of how private companies have tailored their business continuity plans in response to the unique challenges posed by the pandemic. Conclusion: This academic exploration sheds light on the dynamic landscape of business continuity planning in private companies responding to the global pandemic. Insights into the effectiveness of remote work policies, supply chain diversification, employee safety measures, and financial strategies contribute to the understanding of best practices and areas requiring further attention. These recommendations aim to inform future business continuity planning efforts, enhance organizational resilience, and mitigate the impact of global health crises on private sector operations.

ON THE MARTINGALE PROPERTY OF LIMITING DIFFUSION IN SPECIAL DIPLOID MODEL

  • Choi, Won
    • Journal of applied mathematics & informatics
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    • v.31 no.1_2
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    • pp.241-246
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    • 2013
  • Choi [1] identified and characterized the limiting diffusion of this diploid model by defining discrete generator for the rescaled Markov chain. In this note, we define the operator of projection $S_t$ on limiting diffusion and new measure $dQ=S_tdP$. We show the martingale property on this operator and measure. Also we conclude that the martingale problem for diffusion operator of projection is well-posed.