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arXiv 2021年

作者： Tordesillas, Antoinette Kahagalage, Sanath Campbell, Lachlan Bellett, Pat Intrieri, Emanuele Batterham, Robin School of Mathematics & Statistics University of Melbourne Australia GroundProbe Orica Australia Department of Earth Sciences University of Florence Italy Melbourne School of Engineering University of Melbourne Australia

Impending catastrophic failure of granular earth slopes manifests distinct kinematic patterns in space and time. While risk assessments of slope failure hazards have routinely relied on the monitoring of ground motion, such precursory failure patterns remain poorly understood. A key challenge is the multiplicity of spatiotemporal scales and dynamical regimes. In particular, there exist a precursory failure regime where two mesoscale mechanisms coevolve, namely, the preferred transmission paths for force and damage. Despite extensive studies, a formulation which can address their coevolution not just in laboratory tests but also in large, uncontrolled field environments has proved elusive. Here we address this problem by developing a slope stability analytics framework which uses network flow theory and mesoscience to model this coevolution and predict emergent kinematic clusters solely from surface ground motion data. We test this framework on four data sets: one at the laboratory scale using individual grain displacement data;three at the field scale using line-of-sight displacement of a slope surface, from ground-based radar in two mines and from space-borne radar for the 2017 Xinmo landslide. The dynamics of the kinematic clusters deliver an early prediction of the geometry, location and time of failure. © 2021, CC BY-NC-ND.

关键词： Slope stability

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Dealing with Imbalanced Dataset Leveraging Boundary Samples Discovered by Support Vector Data Description

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Computers, Materials & Continua 2021年第3期66卷 2691-2708页

作者： Zhengbo Luo Hamïd Parvïn Harish Garg Sultan Noman Qasem Kim-Hung Pho Zulkefli Mansor Graduate School of Information Production and SystemsWaseda UniversityTokyoJapan Institute of Research and Development Duy Tan UniversityDa Nang550000Vietnam Faculty of Information Technology Duy Tan UniversityDa Nang550000Vietnam Department of Computer Science Nourabad Mamasani BranchIslamic Azad UniversityMamasaniIran School of Mathematics Thapar Institute of Engineering and TechnologyDeemed UniversityPatialaPunjab147004India Computer Science Department College of Computer and Information SciencesAl Imam Mohammad Ibn Saud Islamic UniversityRiyadhSaudi Arabia Computer Science Department Faculty of Applied ScienceTaiz UniversityTaizYemen Fractional Calculus Optimization and Algebra Research GroupFaculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh CityVietnam Fakulti Teknologi dan Sains Maklumat Universiti Kebangsaan MalaysiaSelangorMalaysia

These days,imbalanced datasets,denoted throughout the paper by ID,(a dataset that contains some(usually two)classes where one contains considerably smaller number of samples than the other(s))emerge in many real world problems(like health care systems or disease diagnosis systems,anomaly detection,fraud detection,stream based malware detection systems,and so on)and these datasets cause some problems(like under-training of minority class(es)and over-training of majority class(es),bias towards majority class(es),and so on)in classification process and ***,these datasets take the focus of many researchers in any science and there are several solutions for dealing with this *** main aim of this study for dealing with IDs is to resample the borderline samples discovered by Support Vector Data Description(SVDD).There are naturally two kinds of resampling:Under-sampling(U-S)and oversampling(O-S).The O-S may cause the occurrence of over-fitting(the occurrence of over-fitting is its main drawback).The U-S can cause the occurrence of significant information loss(the occurrence of significant information loss is its main drawback).In this study,to avoid the drawbacks of the sampling techniques,we focus on the samples that may be *** data points that can be misclassified are considered to be the borderline data points which are on border(s)between the majority class(es)and minority class(es).First by SVDD,we find the borderline examples;then,the data resampling is applied over *** the next step,the base classifier is trained on the newly created ***,we compare the result of our method in terms of Area Under Curve(AUC)and F-measure and G-mean with the other state-of-the-art *** show that our method has betterresults than the other state-of-the-art methods on our experimental study.

关键词： Imbalanced learning classification borderline examples

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Coordinating effectively a heart attack pre-hospital service process using constraint optimization programming

Coordinating effectively a heart attack pre-hospital service...

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International Conference on Electrical and Control engineering (ICECE)

作者： Ch. Pylarinou L. Gortzis S. Zimeras Department of Mechanical & Aeronautical Engineering University of Patras Rio Greece School of Medicine University of Patras Rio Greece Department of Statistics and Actuarial-Financial Mathematics University of the Aegean Samos Greece

The most crucial factor when dealing with heart attack incidents is the fast and accurate diagnosis and pre hospital service of the patient. Considering the need of handling time efficiently, emphasis is paid on the interval time management starting from the moment the incident is recognized up to the time the patient is in an emergency unit. In order to control time constraints, we propose a scheduling methodology in which the pre-hospital service is treated as a process consisted of three stages. These stages are represented by activities whose variables help us define accurately the problem. The scheduling of the activities is based on constraint optimization. A case study of five of heart attack reported incidents is analyzed and the results indicate the possible contribution of the application of this methodology. This methodology appears to be very useful, thanks to its ability not only to generate an effective initial schedule as an additional guidance to all participants involved in heart attack service, but also to respond to changes occurred once the first actions have started and abrupt complications necessitate additional or updated actions.

关键词： Optimization Cardiac arrest Hospitals programming Standards Safety

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Phase Selection and Analysis for Multi-frequency Multi-user RIS Systems Employing Subsurfaces in Correlated Ricean and Rayleigh Environments

arXiv

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arXiv 2024年

作者： Inwood, Amy S. Smith, Peter J. Martin, Philippa A. Woodward, Graeme K. Department of Electrical and Computer Engineering Wireless Research Centre University of Canterbury Christchurch New Zealand School of Mathematics and Statistics Victoria University of Wellington Wellington New Zealand

We analyse the performance of a reconfigurable intelligent surface (RIS) aided system where the RIS is divided into subsurfaces. Each subsurface is designed specifically for one user, who is served on their own frequency band. The other subsurfaces (those not designed for this user) provide additional uncontrolled scattering. We derive the exact closed-form expression for the mean signal-to-noise ratio (SNR) of the subsurface design (SD) when all channels experience correlated Ricean fading. We simplify this to find the mean SNR for line-of-sight (LoS) channels and channels experiencing correlated Rayleigh fading. An iterative SD (ISD) process is proposed, where subsurfaces are designed sequentially, and the phases that are already set are used to enhance the design of the remaining subsurfaces. This is extended to a converged ISD (CISD), where the ISD process is repeated multiple times until the SNR increases by less than a specified tolerance. The ISD and CISD both provide a performance improvement over SD, which increases as the number of RIS elements (N) increases. The SD is significantly simpler than the lowest complexity multiuser (MU) method we know of, and despite each user having less bandwidth, the SD outperforms the existing method in some key scenarios. The SD is more robust to strongly LoS channels and clustered users, as it does not rely on spatial multiplexing like other MU methods. Combined with the complexity reduction, this makes the SD an attractive phase selection method. Copyright © 2024, The Authors. All rights reserved.

关键词： Signal to noise ratio

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Using wavelets for fast Monte Carlo simulation of Ising systems with distribution matching

Using wavelets for fast Monte Carlo simulation of Ising syst...

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IEEE/SP Workshop on Statistical Signal Processing (SSP)

作者： John T. Evans Robert R. Snapp Gagan Mirchandani Richard M. Foote School of Engineering University of Vermont Burlington VT USA Department of Computer Science University of Vermont Burlington VT USA Department of Mathematics & Statistics University of Vermont Burlington VT USA

A new wavelet-based method is presented that improves the accuracy of a previously published wavelet-accelerated Monte Carlo analysis of the two-dimensional Ising model by one to two orders of magnitude in the critical and paramagnetic regions, and is up to ten times faster than the standard Metropolis algorithm. In the context of lattice simulations, successive levels of upscaling reduce the number of degrees of freedom, with corresponding gains in computational speed. Empirical results, for a variety of temperatures for a 32 × 32 lattice of binary spins, show that the resulting computational errors are reduced by running simulations at the thermodynamic temperature that minimizes the information-theoretic divergence between the Boltzmann equilibrium distributions of the original and coarse-grained systems. This optimal temperature relationship Monte Carlo method (OTRMC) may also benefit image processing applications, such as image restoration, that employ Monte Carlo simulations of Markov random fields.

关键词： Lattices Monte Carlo methods Magnetization Computational modeling Brain modeling Markov processes Wavelet transforms

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Elastic and Thermodynamic Properties of Complex Mg-Al Intermetallic Compounds via Orbital-Free Density Functional Theory

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Physical Review Applied 2016年第6期5卷 064021-064021页

作者： Houlong Zhuang Mohan Chen Emily A. Carter Department of Mechanical and Aerospace Engineering Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics and Andlinger Center for Energy and the Environment Princeton University Princeton New Jersey 08544 USA

Magnesium-aluminum (Mg-Al) alloys are important metal alloys with a wide range of engineering applications. We investigate the elastic and thermodynamic properties of Mg, Al, and four stoichiometric Mg-Al compounds including Mg17Al12, Mg13Al14, and Mg23Al30, and MgAl2 with orbital-free density-functional theory (OFDFT). We first calculate the lattice constants, zero-temperature formation energy, and independent elastic constants of these six materials and compare the results to those computed via Kohn-Sham DFT (KSDFT) benchmarks. We obtain excellent agreement between these two methods. Our calculated elastic constants of hexagonal close-packed Mg and face-centered-cubic Al are also consistent with available experimental data. We next compute their phonon spectra using the force constants extracted from the very fast OFDFT calculations, because such calculations are computationally challenging using KSDFT. This is especially the case for the Mg23Al30 compound, whose 3×3×3 supercell consists of 1431 atoms. We finally employ the quasiharmonic approximation to investigate temperature-dependent thermodynamic properties, including formation energies, heat capacities, and thermal expansion of the four Mg-Al intermetallic compounds. The calculated heat capacity and thermal expansion of both Mg and Al agree well with experimental data. We additionally find that Mg13Al14 and MgAl2 are both unstable, consistent with their absence from the equilibrium Mg-Al phase diagram. Our work demonstrates that OFDFT is an efficient and accurate quantum-mechanical computational tool for predicting elastic and thermodynamic properties of complicated Mg-Al alloys and also should be applicable to many other engineering alloys.

关键词： Elastic deformation Elastic modulus First-principles calculations Specific heat Thermal expansion Alloys

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Designing Dual Modeling Task Sequences to Build Functional Analysis Learning Trajectories for engineering and Mathematical Sciences Education

Designing Dual Modeling Task Sequences to Build Functional A...

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Frontiers in Education (FIE) Conference

作者： Celil Ekici Pablo Rangel Jose Baca Devanayagam Palaniappan Mehrube Mehrubeoglu Mallikarjunaiah Muddamallappa Department of Mathematics & Statistics Texas A&M University-Corpus Christi Corpus Christi Texas Department of Engineering Texas A&M University-Corpus Christi Corpus Christi Texas

ISBN: (数字)9798350351507

ISBN: (纸本)9798350363067

This research-to-practice paper investigated the development of Functional Analysis Learning Trajectories (FALT) within the undergraduate courses for engineers including Calculus, Differential Equations, Communications Theory, Control Systems and Electromagnetism. Focusing on the local instructional practices, manifestations of functional analysis ideas are tracked along these courses. Corresponding concept maps are collaboratively within and across courses to portray the relevant connections for engineering mathematics education. These trajectories help engineering and mathematics instructors to collectively design, implement, refine task sequences to improve students' preparedness for upper-level math-heavy courses in engineering, connecting mathematics to their disciplines. Here we utilized collaborative concept mapping as a research heuristics to build curricular innovations with functional analysis learning trajectories across courses, hierarchically arranging, integrating, and conceptually connecting instructional tasks. Through sequences of dual stance learning tasks, students are given opportunities to take multiple stances in a learning task from the perspectives of engineers and mathematical scientists. A higher stance on mathematics was supported to be developed by comparing and connecting alternative disciplinary perspectives and practices with the dual modeling tasks and reflecting on the cross-cutting ideas along the learning trajectory. Here we present the collaborative design and analysis of concept maps along functional analysis learning trajectories for undergraduates. This research builds an interdisciplinary scholarship of teaching/learning mathematics across disciplines among engineering and math faculty. This work helps foster reflection and collaboration on their teaching practices to design and implement instructional tasks to build coherent mathematical perspectives across disciplines. It exemplifies how to design a research-based practices

关键词： Technological innovation Analytical models Scholarships Education Collaboration mathematics Functional analysis Mathematical models Reflection Trajectory

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An ultrasonic measurement of stress in steel without calibration: The angled shear wave identity

arXiv

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arXiv 2020年

作者： Li, Guo-Yang Gower, Artur L. Destrade, Michel Harvard Medical School Wellman Center for Photomedicine Massachusetts General Hospital BostonMA02114 United States Department of Mechanical Engineering University of Sheffield Sheffield United Kingdom School of Mathematics Statistics and Applied Mathematics NUI Galway Galway Ireland

Measuring stress levels in loaded structures is crucial to assess and monitor their health, and to predict the length of their remaining structural life. However, measuring stress non-destructively has proved quite challenging. Many ultrasonic methods are able to accurately predict in-plane stresses in a controlled laboratory environment, but struggle to be robust outside, in a real world setting. That is because they rely either on knowing beforehand the material constants (which are difficult to acquire) or they require significant calibration for each specimen. Here we present a simple ultrasonic method to evaluate the in-plane stress in situ directly, without knowing any material constants. This method only requires measuring the speed of two angled shear waves. It is based on a formula which is exact for incompressible solids, such as soft gels or tissues, and is approximately true for compressible "hard" solids, such as steel and other metals. We validate the formula against virtual experiments using Finite Element simulations, and find it displays excellent accuracy, with a small error of the order of 1%.MSC Codes 74J05, 74J25, 74B10, 74B15 Copyright © 2020, The Authors. All rights reserved.

关键词： Shear waves

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Generalized concatenated codes with quasi-cyclic codes as outer code

Generalized concatenated codes with quasi-cyclic codes as ou...

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IEEE International Symposium on Information Theory

作者： M. Esmaeili T.A. Gulliver N.P. Secord Department of Mathematics & Statistics Carleton University Ottawa ONT Canada Department of Electrical & Computer Engineering University of Canterbury Christchurch New Zealand Communications Rcscarch Centre Ottawa ONT Canada

The cyclic structure of quasi-cyclic (QC) codes results in a simple trellis representation. This representation makes them suitable for use in soft-decision decoding applications. We examine concatenated codes with qu... 详细信息

关键词： Concatenated codes Block codes Decoding mathematics statistics Computational Intelligence Society Convolutional codes Very large scale integration Councils Telecommunications

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Two-stage IDS for IoT using layered machine- and deep-learning models

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Cyber-Physical Systems 2024年第1期10卷 60-83页

作者： van der Walt, André Quazi, Tahmid van Niekerk, Brett School of Engineering University of KwaZulu-Natal Durban South Africa School of Mathematics Statistics and Computer Science University of KwaZuluNatal South Africa Department of Information Technology Durban University of Technology South Africa

The ever-growing integration of Internet-of-Things (IoT) devices into our daily lives provides us with a level of convenience never before seen. However, the effects of attacks on these devices can be devastating. The discrete, low-powered nature of IoT devices makes their security a difficult problem to solve. To provide a solution, this work proposes a two-stage Intrusion Detection Systems (IDS) using layered machine and deep learning models. The potential benefits of the system are examined and the results presented show a reduction of threat detection/identification time of 0.51 s on average and an increase of threat classification F1-Score by 0.05. . © 2022 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Internet of things

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