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Extending finite mixtures of nonlinear mixed-effects models with covariate-dependent mixing weights

Advances in data Analysis and Classification 2024年第2期18卷 271-307页

作者： Wang, Wan-Lun Yang, Yu-Chen Lin, Tsung-I Institute of Statistics National Chung Hsing University Taichung402 Taiwan Department of Public Health China Medical University Taichung404 Taiwan Department of Statistics and Institute of Data Science National Cheng Kung University Tainan701 Taiwan Department of Applied Mathematics National Chung Hsing University Taichung402 Taiwan

Finite mixtures of nonlinear mixed-effects models have emerged as a prominent tool for modeling and clustering longitudinal data following nonlinear growth patterns with heterogeneous behavior. This paper proposes an extended finite mixtures of nonlinear mixed-effects model in which the mixing proportions are related to some explanatory covariates. A logistic function is incorporated to describe the relationship between the prior classification probabilities and the covariates of interest. For parameter estimation, we develop an analytically simple expectation conditional maximization algorithm coupled with the first-order Taylor approximation to linearize the model with pseudo data. The calculation of the standard errors of estimators via a general information-based method and the empirical Bayes estimation of random effects are also discussed. The methodology is illustrated through several simulation experiments and an application to the AIDS Clinical Trials Group Protocol 315 study. © Springer-Verlag GmbH Germany, part of Springer Nature 2022.

关键词： Mixtures

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Web service location-allocation using discrete NSGA-II with matrix based genetic operations and a repair mechanism

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Journal of Ambient Intelligence and Humanized Computing 2023年第10期14卷 14163-14187页

作者： Verma, Shanu Pant, Millie Snasel, Vaclav Department of Applied Mathematics and Scientific Computing Indian Institute of Technology Roorkee Roorkee247667 India Centre for Artificial Intelligence and Data Science Indian Institute of Technology Roorkee Roorkee247667 India Department of Computer Science VSB-Technical University of Ostrava Ostrava70800 Czech Republic

Web Service Location-Allocation Problem (WSLAP) is an important and challenging NP-hard combinatorial optimization problem where multiple objectives affecting the quality of service (QoS) are to be optimized simultaneously. Most of the existing research articles mainly focus on selecting web service locations that minimize two QoS: total cost and total response time. However, another QoS factor throughput also needs attention when selecting sites for allocating web services. Therefore, we have constructed a new WSLAP model that minimizes the total cost and the total negative quality factor. This negative quality factor considers throughput along with latency to strengthen the QoS of the located web services. Further, three NSGA-II variants, NSGA-II.V1, NSGA-II.V2, and NSGA-II.V3, with a novel matrix-based chromosome representation, are developed to deal with the proposed bi-objective WSLAP model. These algorithms involve matrix-based genetic operations for better exploration and a repair mechanism for tackling infeasibility. The proposed model and algorithms are validated on 24 test instances, out of which 14 are existing, and 10 are newly created with increased web services, user centres and service locations. The experimental results claim that the proposed WSLAP model succeeded in improving the throughput with a comparatively lower total cost. Further, the proposed algorithms outperformed the compared algorithms in terms of hypervolume, inverted generational distance and computational time on 89% of instances. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Quality of service

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A Particle Algorithm for Mean-Field Variational Inference

arXiv

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arXiv 2024年

作者： Du, Qiang Wang, Kaizheng Zhang, Edith Zhong, Chenyang Department of Applied Physics and Applied Mathematics Data Science Institute Columbia University United States Department of Industrial Engineering and Operations Research Data Science Institute Columbia University United States Department of Applied Physics and Applied Mathematics Columbia University United States Department of Statistics Columbia University United States

Variational inference is a fast and scalable alternative to Markov chain Monte Carlo and has been widely applied to posterior inference tasks in statistics and machine learning. A traditional approach for implementing mean-field variational inference (MFVI) is coordinate ascent variational inference (CAVI), which relies crucially on parametric assumptions on complete conditionals. In this paper, we introduce a novel particle-based algorithm for mean-field variational inference, which we term PArticle VI (PAVI). Notably, our algorithm does not rely on parametric assumptions on complete conditionals, and it applies to the nonparametric setting. We provide non-asymptotic finite-particle convergence guarantee for our algorithm. To our knowledge, this is the first end-to-end guarantee for particle-based MFVI. Copyright © 2024, The Authors. All rights reserved.

关键词： Vlasov equation

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Deep-Learning Super-Resolution for High-Speed Excitation-Emission Matrix Measurements 4

Deep-Learning Super-Resolution for High-Speed Excitation-Emi...

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AI and Optical data sciences IV 2023

作者： Michelucci, Umberto Fluri, Silvan Baumgartner, Michael Venturini, Francesca TOELT LLC Research and Development Dübendorf Switzerland Lucerne University of Applied Sciences and Arts Computer Science Department Lucerne Switzerland Institute of Applied Mathematics and Physics Zurich University of Applied Sciences Winterthur Switzerland

ISBN: (纸本)9781510659810

In many optical experiments, a long measurement time is necessary to collect enough information and improve the signal-to-noise ratio. This happens, for example, in total luminescence spectroscopy (TLS) where the data is acquired as excitation-emission matrices (EEMs). An EEM is an unique chemical fingerprint of the analyzed substance that allows its comprehensive characterization. To collect a high-resolution EEM, it is necessary to scan both the excitation and the emission wavelengths in small steps and, for each step, to collect the light for a long time to maximize the signal-to-noise ratio. Therefore, acquiring a high-resolution excitation emission matrix can take more than an hour, depending on the size of the wavelength steps, the intensity of the signal, and the spectral range to be analyzed. This paper proposes a new method to reconstruct a high-resolution EEM from low-resolution one using deep learning super-resolution techniques. Specifically, this work proposes a new artificial neural network architecture, a sub-pixel convolutional neural network, designed to be applied to fluorescence EEM images. The code used is made available via a GitHub repository with instructions for applying transfer learning to different types of images. © 2023 SPIE.

关键词： Signal to noise ratio

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Ohta-Kawasaki energy for amphiphiles: asymptotics and phase-field simulations

arXiv

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arXiv 2024年

作者： Du, Qiang Scott, James M. Xu, Zirui Department of Applied Physics and Applied Mathematics Data Science Institute Columbia University New YorkNY10027 United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States

We study the minimizers of a degenerate case of the Ohta–Kawasaki energy, defined as the sum of the perimeter and a Coulombic nonlocal term. We start by investigating radially symmetric candidates which give us insights into the asymptotic behaviors of energy minimizers in the large mass limit. In order to numerically study the problems that are analytically challenging, we propose a phase-field reformulation which is shown to Gamma-converge to the original sharp interface model. Our phase-field simulations and asymptotic results suggest that the energy minimizers exhibit behaviors similar to the self-assembly of amphiphiles, including the formation of lipid bilayer *** Codes 49Q20 (Primary) 35Q92, 35B36 (Secondary) Copyright © 2024, The Authors. All rights reserved.

关键词： Self assembly

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Exact Soliton Solutions and Dynamical Behaviors of Hausdorff Fractal Fokas–Lenells Equation

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International Journal of applied and Computational mathematics 2025年第2期11卷 1-20页

作者： Abdelkhalek, A. El-Kalla, I.L. Elsaid, A. Kader, A. H. Abdel Mathematics and Engineering Physics Department Faculty of Engineering Mansoura University PO 35516 Mansoura Egypt Department of Mathematics Institute of Basic and Applied Sciences Egypt-Japan University of Science and Technology (E-JUST) New Borg El-Arab City Alexandria Egypt Mathematics Department Faculty of Science New Mansoura University New Mansoura City Egypt

In this paper, the Hausdorff Fractal Fokas-Lenells (HFFL) equation with full nonlinearity is investigated. The travelling wave reduction technique is utilized to transform the HFFL equation into an ordinary differential equation that can be converted to a two-dimensional planar dynamical system. By applying the direct integration method, some doubly periodic solutions are obtained for the HFFL equation in the form of Jacobi elliptic functions and Weierstrass function. New peakon, kink, bright, dark, W-shaped, and M-shaped solitons solutions for the HFFL equation are found under some constraints. The two-dimensional planar dynamical system is investigated to calculate the equilibrium points, which are classified as hyperbolic and nonhyperbolic equilibrium points. The theories of dynamical systems are employed to analyze the stability of individual equilibrium points as well as the bifurcation of the system's dynamics. Vector fields are plotted in the two-dimensional phase portraits to explore the dynamics near each equilibrium point. © The Author(s), under exclusive licence to Springer Nature India Private Limited 2025.

关键词： Bifurcation Doubly periodic Fokas–Lenells Hausdorff fractal Nonlinear dynamics Solitons

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Correlations in interacting electron liquids: Many-body statistics and hyperuniformity

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Physical Review B 2024年第10期110卷 104201页

作者： Haina Wang Rhine Samajdar Salvatore Torquato Department of Chemistry Department of Physics Princeton Center for Theoretical Science Princeton Materials Institute Program in Applied and Computational Mathematics

Disordered hyperuniform many-body systems are exotic states of matter with novel optical, transport, and mechanical properties. These systems are characterized by an anomalous suppression of large-scale density fluctuations compared to ordinary liquids. The structure factor of disordered hyperuniform systems often obeys the scaling relation S(k)∼Bkα with B,α>0 in the limit k→0. Ground states of d-dimensional free fermionic gases, which are fundamental models for many metals and semiconductors, are key examples of quantum disordered hyperuniform states with important connections to random matrix theory. However, the effects of electron-electron interactions as well as the polarization of the electron liquid on hyperuniformity have not been explored thus far. In this paper, we systematically address these questions by deriving the analytical small-k behaviors (and, associated, α and B) of the total and spin-resolved structure factors of quasi-one-dimensional, two-dimensional, and three-dimensional electron liquids for varying polarizations and interaction parameters. We validate that these equilibrium disordered ground states are hyperuniform, as dictated by the fluctuation-compressibility relation. Interestingly, free fermions, partially polarized interacting fermions, and fully polarized interacting fermions are characterized by different values of the small-k scaling exponent α and coefficient B. In particular, partially polarized fermionic liquids exhibit a unique form of multihyperuniformity, in which the net configuration exhibits a stronger form of hyperuniformity (i.e., larger α) than each individual spin component. The detailed theoretical analysis of such small-k behaviors enables the construction of corresponding equilibrium classical systems under effective one- and two-body interactions that mimic the pair statistics of quantum electron liquids. Our paper thus reveals that highly unusual hyperuniform and multihyperuniform states can be achieved in simple

关键词： Electronic structure Quantum many-body systems Two-dimensional electron gas

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Zinc Oxide/Carbon Material-Embedded Supramolecular Drug Delivery System with Photoswitching Properties for Highly Selective and Effective Chemotherapy

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ACS applied Bio Materials 2024年第8期7卷 5506-5518页

作者： Ilhami, Fasih Bintang Munasir, None Gultom, Noto Susanto Cheng, Chih-Chia Department of Natural Science Faculty of Mathematics and Natural Science Universitas Negeri Surabaya Surabaya60231 Indonesia Department of Physics Faculty of Mathematics and Natural Science Universitas Negeri Surabaya Surabaya60231 Indonesia Department of Physics Universitas Padjadjaran Bandung45363 Indonesia Graduate Institute of Applied Science and Technology National Taiwan University of Science and Technology Taipei10607 Taiwan Advanced Membrane Materials Research Center National Taiwan University of Science and Technology Taipei10607 Taiwan

Phototherapy has become a hopeful procedure for the treatment of cancer. Nevertheless, the straightforward creation of a theranostic system that can achieve both tumor localization and production of oxygen species is greatly desired yet remains a challenging endeavor. In this study, we synthesized spherical nanostructures by decorating zinc oxide (ZnO) with peanut shell-based carbon (PNS-C) in an aqueous solution. The PNS-C-decorated ZnO (ZnO/PNS-C)-embedded supramolecular system exhibited spontaneous self-assembly. The nanogels that are produced have several desirable characteristics, including exceptional resistance to degradation by light, highly stable nanostructures that form spontaneously in biological environments, outstanding ability to prevent the destruction of red blood cells, and a high level of sensitivity to changes in pH and light. Under light irradiation, the addition of ZnO/PNS-C-incorporated supramolecular provided high reactive oxygen species production. Moreover, in vitro cellular assays demonstrated ZnO/PNS-C-incorporated supramolecular exhibited highly selective and induced phototoxicity into cancer cells and no effect on the viability of normal cells both before and after irradiation. Overall, the ZnO/PNS-C-incorporated supramolecular system has the potential to stimulate advancements in phototherapy by utilizing highly tumor-selective therapeutic molecules. This can lead to a more effective targeted therapy for cancers. © 2024 American Chemical Society.

关键词： Diseases

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Detailed discussion of discrepancy between theoretical and observed spectral lines in Kr-like W^(38+)based on advanced consideration of core electron correlations

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Chinese physics B 2025年第5期34卷 328-337页

作者： Guo-Qing Peng Kai Wang Jun Yan Wei Kang Center for Applied Physics and Technology Peking UniversityBeijing 100871China Department of Physics and Anhui Key Laboratory of Optoelectric Materials Science and Technology Key Laboratory of Functional Molecular SolidsMinistry of EducationAnhui Normal UniversityWuhu 241000China Institute of Applied Physics and Computational Mathematics Beijing 100088China

For the observed line at 799.23°A in tungsten EBIT experiment,which was assigned to be^(3)F_(4)^(o)−^(3)F_(3)^(o)([Ar]4s^(2)4p^(5)4d)of W^(38+)ion,there were noticeable deviations for most calculated wavelengths from the measured *** clarify this issue,we carry out an extensive calculation for energy levels and transition properties of W^(38+)ion using the multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction method,in which more deeper inner core electron correlations are included,and different forms of Breit interaction as well as quantum electrodynamics corrections are *** is found that the inner core electron correlations can affect the total energy of levels,while only slightly modify the excited energy of levels in 4s^(2)4p^(5)4d *** present calculated wavelengths agree with the corresponding measured values excellently except the line at 799.23Å.Thus we are strongly suspicious this line should be misidentified,and suggest that new experiment with higher resolution and spectra analysis based on more accurate atomic data should be performed for W^(38+)ion.

关键词： Kr-like W^(38+) the multi-configuration Dirac-Hartree-Fock(MCDHF)method electron correlation imbalance Breit interaction quantum electrodynamic(QED)

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A generalized software reliability prediction model for module based software incorporating testing effort with cost model

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Life Cycle Reliability and Safety Engineering 2024年第4期13卷 419-436页

作者： Yadav, Akshay Kumar Srivastava, Shilpa Pant, Millie Department of Applied Mathematics and Scientific Computing Indian Institute of Technology Roorkee 247001 India Christ University Karnataka Bengaluru 560029 India Mehta Family School of Data Science and Artificial Intelligence Indian Institute of Technology Roorkee 247667 India

As software innovation has advanced, it has been noted that the testing effort function (TEF) is one of the key factors influencing the improvement of software reliability. This paper presents a simplified model which incorporates the testing effort for the reliability growth of a software. A closed form solution has been derived for the reliability of the software. This study examines the impact of testing efforts on a software reliability model based on NHPP. The sensitivity analysis has been made available to investigate how the created model's system parameters affect the cost function, mean value function, and software’s reliability. The parameters of the model have been estimated using the non-linear least square estimation (MLE) method in MATLAB software. Additionally, a warranty cost model is constructed to assess the optimal release policy for the software. The general form of the reliability expression involves elliptic integrals, which can be computed easily through a software like Mathematica. We have derived analytical solutions for reliability pertaining to several particular cases. Optimal release time for the software product has been calculated for some particular cost-sets. Goodness of fit curves have been plotted to compare the proposed model with some well-known existing SRGMs. Numerical illustrations are provided to bolster the analytical outcomes. © The Author(s), under exclusive licence to Society for Reliability and Safety (SRESA) 2024.

关键词： Maximum likelihood estimation (MLE) Non-homogeneous Poisson process (NHPP) Optimal release time (ORT) Software reliability growth model (SRGM) Testing effort function (TEF) Warranty cost model

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