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arXiv 2019年

作者： Crum, Justin Levine, Joshua A. Gillette, Andrew Program in Applied Mathematics University of Arizona Department of Computer Science University of Arizona Department of Mathematics University of Arizona

Fractional partial differential equations (FDEs) are used to describe phenomena that involve a "non-local" or "long-range" interaction of some kind. Accurate and practical numerical approximation of their solutions is challenging due to the dense matrices arising from standard discretization procedures. In this paper, we begin to extend the well-established computational toolkit of Discrete Exterior Calculus (DEC) to the fractional setting, focusing on proper discretization of the fractional derivative. We define a Caputo-like fractional discrete derivative, in terms of the standard discrete exterior derivative operator from DEC, weighted by a measure of distance between p-simplices in a simplicial complex. We discuss key theoretical properties of the fractional discrete derivative and compare it to the continuous fractional derivative via a series of numerical experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Calculations

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Advising big data transfer over dedicated connections based on profiling optimization

Advising big data transfer over dedicated connections based ...

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作者： Yun, Daqing Wu, Chase Q. Rao, Nageswara S. V. Kettimuthu, Rajkumar Computer and Information Sciences Program Harrisburg University HarrisburgPA17101 United States Department of Computer Science New Jersey Institute of Technology NewarkNJ07102 United States Computer Science and Mathematics Division Oak Ridge National Laboratory Oak RidgeTN37831 United States Data Science and Learning Division Argonne National Laboratory ArgonneIL60439 United States

Big data transfer in next-generation scientific applications is now commonly carried out over dedicated channels in high-performance networks (HPNs), where transport protocols play a critical role in maximizing application-level throughput. Optimizing the performance of these protocols is challenging: i) transport protocols perform differently in various network environments, and the protocol choice is not straightforward;ii) even for a given protocol in a given environment, different parameter settings of the protocol may lead to significantly different performance and oftentimes the default setting does not yield the best performance. However, it is prohibitively time-consuming to conduct exhaustive transport profiling due to the large parameter space. In this paper, we propose a PRofiling Optimization Based DAta Transfer Advisor (ProbData) to help end users determine the most effective transport method with the most appropriate parameter settings to achieve satisfactory performance for big data transfer over dedicated connections in HPNs. ProbData employs a fast profiling scheme based on the Simultaneous Perturbation Stochastic Approximation algorithm, namely, FastProf, to accelerate the exploration of the optimal operational zones of various transport methods to improve profiling efficiency. We first present a theoretical background of the optimized profiling approach in ProbData and then detail its design and implementation. The advising procedure and performance benefits of FastProf and ProbData are illustrated and evaluated by both extensive emulations based on real-life performance measurements and experiments over various physical connections in existing production HPNs. © 1993-2012 IEEE.

关键词： Data transfer

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Provenance management in Swift

Provenance management in Swift

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作者： Gadelha Jr., Luiz M.R. Clifford, Ben Mattoso, Marta Wilde, Michael Foster, Ian Computer and Systems Engineering Program Federal University of Rio de Janeiro Brazil National Laboratory for Scientific Computing Brazil Computation Institute University of Chicago United States Mathematics and Computer Science Division Argonne National Laboratory United States

The Swift parallel scripting language allows for the specification, execution and analysis of large-scale computations in parallel and distributed environments. It incorporates a data model for recording and querying provenance information. In this article we describe these capabilities and evaluate the interoperability with other systems through the use of the Open Provenance Model. We describe Swift's provenance data model and compare it to the Open Provenance Model. We also describe and evaluate activities performed within the Third Provenance Challenge, which consisted of implementing a specific scientific workflow, capturing and recording provenance information of its execution, performing provenance queries, and exchanging provenance information with other systems. Finally, we propose improvements to both the Open Provenance Model and Swift's provenance system. © 2011 Elsevier B.V. All rights reserved.

关键词： Interoperability

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An independent set approach for the communication network of the GPS III system

An independent set approach for the communication network of...

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作者： Brinkmann, Gunnar Crevals, Simon Frye, John Applied Mathematics and Computer Science Ghent University Krijgslaan 281 S9 9000 Ghent Belgium Lockheed Martin GPS III Program 100 Campus Drive Newtown PA 18940 United States

In this article, we describe an algorithm to find the optimal communication network for the new GPS III satellite system. Finding a possible network will be translated to a maximum clique problem and an efficient algorithm for finding all maximum cliques under these special circumstances is described. © 2011 Elsevier B.V. All rights reserved.

关键词： Network security

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Approximation, Randomization, and Combinatorial Optimization: Algorithms and Techniques 1

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丛书名： Lecture Notes in computer science

1000年

作者： Michel Goemans Klaus Jansen José D. P. Rolim Luca Trevisan

ISBN: (数字)9783540446668

ISBN: (纸本)9783540424703

This book constitutes the joint refereed proceedings of the 4th International Workshop on Approximation Algorithms for Optimization Problems, APPROX 2001 and of the 5th International Workshop on Ranomization and Approximation Techniques in computer science, RANDOM 2001, held in Berkeley, California, USA in August 2001. The 26 revised full papers presented were carefully reviewed and selected from a total of 54 submissions. Among the issues addressed are design and analysis of approximation algorithms, inapproximability results, on-line problems, randomization, de-randomization, average-case analysis, approximation classes, randomized complexity theory, scheduling, routing, coloring, partitioning, packing, covering, computational geometry, network design, and applications in various fields.

关键词： Analysis programming Techniques Discrete mathematics Algorithm Analysis and Problem Complexity Numeric Computing Combinatorics

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Unbiased Estimation of the Vanilla and Deterministic Ensemble Kalman–Bucy Filters

arXiv

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arXiv 2022年

作者： Álvarez Ballesteros, Miguel Ángel Chada, Neil K. Jasra, Ajay Applied Mathematics and Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

In this article we consider the development of an unbiased estimator for the ensemble Kalman–Bucy filter (EnKBF). The EnKBF is a continuous-time filtering methodology which can be viewed as a continuous-time analogue of the famous discrete-time ensemble Kalman filter. Our unbiased estimators will be motivated from recent work [Rhee & Glynn 2010, [31]] which introduces randomization as a means to produce unbiased and finite variance estimators. The randomization enters through both the level of discretization, and through the number of samples at each level. Our estimator will be specific to linear and Gaussian settings, where we know that the EnKBF is consistent, in the particle limit N → ∞, with the KBF. We highlight this for two particular variants of the EnKBF, i.e. the deterministic and vanilla variants, and demonstrate this on a linear Ornstein–Uhlenbeck process. We compare this with the EnKBF and the multilevel (MLEnKBF), for experiments with varying dimension size. We also provide a proof of the multilevel deterministic EnKBF, which provides a guideline for some of the unbiased methods. © 2022, CC BY-NC-SA.

关键词： Continuous time systems

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The impact of digital literacy and internet usage on health behaviors and decision-making in Arab MENA countries

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Technology in Society 2025年 82卷

作者： Tayyem, Reema Qasrawi, Radwan Sabbah, Haleama Al Amro, Malak Issa, Ghada Thwib, Suliman Atari, Siham Hani Bookari, Khlood Alawadhi, Noor Allehdan, Sabika Trigui, Hana Sokhn, Elie Khader, Yousef Badran, Eman Kamel, Iman Abdallah, Atiyeh Jemaà, Mohamed Musa, Emmanuel Kong, Jude Dzevela -Health Qatar University Doha Qatar Department of Computer Science Al-Quds University Jerusalem Palestine Department of Computer Engineering Istinye University Istanbul Turkey Department of Public Health College of Health Sciences Abu Dhabi University UAE Dubai United Arab Emirates Department of Clinical Nutrition Faculty of Applied Medical Sciences Taibah University Medina Saudi Arabia School of Education Kuwait University Kuwait Department of Biology College of Science University of Bahrain Zallaq Bahrain Laboratoire de Microbiologie Moléculaire Vaccinologie et Développement Biotechnologique Institut Pasteur de Tunis The University of Tunis El Manar Tunisia Molecular Testing Laboratory Medical Laboratory Department Faculty of Health Sciences Beirut Arab University Beirut Lebanon Department of Public Health Faculty of Medicine Jordan University of Science and Technology Jordan Pediatric Department Neonatal-Perinatal Division University of Jordan Faculty of Medicine Jordan National Research Centre Cairo 11884 Egypt Department of Biomedical Sciences College of Health Sciences QU Health Sector Qatar University Doha2713 Qatar Human Genetics Laboratory Faculty of Medicine of Tunis Tunis El Manar University Tunis Tunisia Neurophysiology Cellular Physiopathology and Valorisation of Biomolecules Laboratory Faculty of Sciences of Tunis Tunis El Manar University Tunis Tunisia Department of Biology Faculty of Sciences of Tunis Tunis El Manar University Tunis Tunisia AI4PEP York University Toronto Canada Department of Mathematics and Statistics Faculty of Science York University Canada

Background: Digital literacy is essential for health behaviors and decision-making, particularly in Arab MENA countries, where access to digital resources varies considerably. Objective: This study investigates the impact of digital literacy and internet usage on health behaviors across ten Arab countries, focusing on demographic and country-specific differences. Methods: A cross-sectional survey of 12,522 respondents from Bahrain, Palestine, Lebanon, Jordan, Kuwait, the UAE, Saudi Arabia, Egypt, Morocco, and Tunisia was conducted using convenience sampling combined with the SMOTE-ENN technique to ensure balanced representation. The online questionnaire, available in Arabic and English, assessed internet access, digital literacy, and health behaviors. Results: The findings reveal notable disparities in how digital literacy affects health outcomes. Overall, 40 % reported positive impacts of digital literacy on health behaviors, with males and older age groups showing higher positive perceptions. Notable country differences were observed: Egypt reported the highest positive impact (65.1 %), while Kuwait had the highest negative impact (25.3 %). Urban residents and those with higher education levels experienced more positive effects. Reliable internet access, social media, and health apps positively influenced health outcomes, particularly in Egypt and the UAE. Conclusion: The findings emphasize the importance of enhancing digital health literacy, particularly for marginalized and underserved groups and communities. Improving internet access, fostering confidence in digital tools, and promoting critical evaluation of health information are crucial for positive health outcomes. This study offers key insights into the role of digital literacy in public health and highlights the need to address disparities in the Arab MENA region. © 2025 Elsevier Ltd

关键词： Electronic health record

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Unbiased and Multilevel Methods for a Class of Diffusions Partially Observed via Marked Point Processes

arXiv

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arXiv 2023年

作者： Alvarez, Miguel Jasra, Ajay Ruzayqat, Hamza Applied Mathematics and Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

In this article we consider the filtering problem associated to partially observed diffusions, with observations following a marked point process. In the model, the data form a point process with observation times that have its intensity driven by a diffusion, with the associated marks also depending upon the diffusion process. We assume that one must resort to time-discretizing the diffusion process and develop particle and multilevel particle filters to recursively approximate the filter. In particular, we prove that our multilevel particle filter can achieve a mean square error (MSE) of O(∈2) (∈ > 0 and arbitrary) with a cost of O(∈-2.5) versus using a particle filter which has a cost of O(∈-3) to achieve the same MSE. We then show how this methodology can be extended to give unbiased (that is with no time-discretization error) estimators of the filter, which are proved to have finite variance and with high-probability have finite cost. Finally, we extend our methodology to the problem of online static-parameter estimation. Key words: Unbiased Methods, Multilevel Monte Carlo, Non-Linear Filtering, Point Processes, Parameter *** Codes 60G55, 60G35, 62M20, 62F30 © 2023, CC BY.

关键词： Diffusion

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Bayesian Parameter Inference for Partially Observed Stochastic Volterra Equations

arXiv

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arXiv 2023年

作者： Jasra, Ajay Ruzayqat, Hamza Wu, Amin Applied Mathematics & Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

In this article we consider Bayesian parameter inference for a type of partially observed stochastic Volterra equation (SVE). SVEs are found in many areas such as physics and mathematical finance. In the latter field they can be used to represent long memory in unobserved volatility processes. In many cases of practical interest, SVEs must be time-discretized and then parameter inference is based upon the posterior associated to this time-discretized process. Based upon recent studies on time-discretization of SVEs (e.g. [24]) we use Euler-Maruyama methods for the afore-mentioned discretization. We then show how multilevel Markov chain Monte Carlo (MCMC) methods [19] can be applied in this context. In the examples we study, we give a proof that shows that the cost to achieve a 4 mean square error (MSE) of O(ϵ2), ϵ > 0, is O(ϵ− 4/2H+1 ), where H is the Hurst parameter. If one uses a single level MCMC method then the cost is O(ϵ−2(2H+3)/ 2H+1 ) to achieve the same MSE. We illustrate these results in the context of state-space and stochastic volatility models, with the latter applied to real *** Codes 62F15, 62M20, 60J10, 60J22, 65C40 © 2023, CC BY.

关键词： Mean square error

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Nonlinear analysis of condensed-phase surface combustion

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European Journal of applied mathematics 1990年第1期1卷 73-89页

作者： Garbey, Marc Kaper, Hans G. Leaf, Gary K. Matkowsky, Bernard J. Department of Mathematics Ecole Normale Superieure de Lyon 69364 Lyon cedex 07 France Mathematic and Computer Science Division Argonne National Laboratory Argonne IL 60439-4801 United States Department of Engineering Sciences and Applied Mathematics Northwestern University Evanston IL 60208 United States

This article is concerned with the structure and stability properties of a combustion front that propagates in the axial direction along the surface of a cylindrical solid fuel element. The fuel consists of a mixture of two finely ground metallic powders, which combine upon ignition in a one-step chemical reaction. The reaction is accompanied by a melting process, which in turn enhances the reaction rate. The combustion products are in the solid state. The reaction zone, inside which the melting occurs, is modelled as a front that propagates along the surface of the cylinder. The different modes of propagation that have been observed experimentally (such as single- and multiheaded spin combustion and multiple-point combustion) are explained as the results of bifurcations from a uniformly propagating plane circular front. The stability properties of the various modes are discussed. © 1990, Cambridge University Press. All rights reserved.

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