143 results
Search Results
2. Improved, extended, and total impact factor of a journal*
- Author
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Florentin Smarandache
- Subjects
FOS: Computer and information sciences ,00A69 ,Impact factor ,Recall ,Short paper ,Econometrics ,Computer Science - Digital Libraries ,Digital Libraries (cs.DL) ,General Medicine ,Mathematics - Abstract
In this short paper we recall the (Garfield) Impact Factor of a Journal, we improve and extend it, and eventually we present the Total Impact Factor that reflects the most accurate impact factor., Comment: 5 pages
- Published
- 2020
3. PETSc/TAO Developments for Early Exascale Systems
- Author
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Mills, Richard Tran, Adams, Mark, Balay, Satish, Brown, Jed, Faibussowitsch, Jacob, Isaac, Toby, Knepley, Matthew, Munson, Todd, Suh, Hansol, Zampini, Stefano, Zhang, Hong, and Zhang, Junchao
- Subjects
Computer Science - Mathematical Software ,Computer Science - Distributed, Parallel, and Cluster Computing ,00A69 - Abstract
The Portable Extensible Toolkit for Scientific Computation (PETSc) library provides scalable solvers for nonlinear time-dependent differential and algebraic equations and for numerical optimization via the Toolkit for Advanced Optimization (TAO). PETSc is used in dozens of scientific fields and is an important building block for many simulation codes. During the U.S. Department of Energy's Exascale Computing Project, the PETSc team has made substantial efforts to enable efficient utilization of the massive fine-grain parallelism present within exascale compute nodes and to enable performance portability across exascale architectures. We recap some of the challenges that designers of numerical libraries face in such an endeavor, and then discuss the many developments we have made, which include the addition of new GPU backends, features supporting efficient on-device matrix assembly, better support for asynchronicity and GPU kernel concurrency, and new communication infrastructure. We evaluate the performance of these developments on some pre-exascale systems as well the early exascale systems Frontier and Aurora, using compute kernel, communication layer, solver, and mini-application benchmark studies, and then close with a few observations drawn from our experiences on the tension between portable performance and other goals of numerical libraries., Comment: 15 pages, submitted to IJHPCA
- Published
- 2024
4. A measurement of the Earth's radius for high school students
- Author
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Neri, Davide
- Subjects
Physics - Physics Education ,00A69 - Abstract
In the Tuscan Archipelago (Italy) it's possible to make an approximate measurement of the Earth's radius from the Elba Island using the Pianosa Island as a ship that appears and disappears on the horizon depending on the observer's height above sea level. The necessary calculations require the mathematical skills of the first two years of high school. The measurement described here refers to a particular geographical location, but it can probably be repeated in similar situations around the world., Comment: 4 pages, 4 figures, typos corrected
- Published
- 2023
5. Improved, Extended, and Total Impact Factor of a Journal
- Author
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Smarandache, Florentin
- Subjects
Computer Science - Digital Libraries ,00A69 - Abstract
In this short paper we recall the (Garfield) Impact Factor of a Journal, we improve and extend it, and eventually we present the Total Impact Factor that reflects the most accurate impact factor., Comment: 5 pages
- Published
- 2021
6. Advanced Control Algorithm for FADEC Systems in the Next Generation of Turbofan Engines to Minimize Emission Levels.
- Author
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Aghasharifian Esfahani, Majid, Namazi, Mohammadmehdi, Nikolaidis, Theoklis, and Jafari, Soheil
- Subjects
TURBOFAN engines ,GENETIC algorithms ,FUZZY logic ,GAS turbines ,ALGORITHMS ,GREENHOUSE gas mitigation - Abstract
New propulsion systems in aircrafts must meet strict regulations and emission limitations. The Flightpath 2050 goals set by the Advisory Council for Aviation Research and Innovation in Europe (ACARE) include reductions of 75%, 90%, and 65% in CO
2 , NOx , and noise, respectively. These goals are not fully satisfied by marginal improvements in gas turbine technology or aircraft design. A novel control design procedure for the next generation of turbofan engines is proposed in this paper to improve Full Authority Digital Engine Control (FADEC) systems and reduce the emission levels to meet the Flightpath 2050 regulations. Hence, an Adaptive Network–based Fuzzy Inference System (ANFIS), nonlinear autoregressive network with exogenous inputs (NARX) techniques, and the block-structure Hammerstein–Wiener approach are used to develop a model for a turbofan engine. The Min–Max control structure is chosen as the most widely used practical control algorithm for gas turbine aero engines. The objective function is considered to minimize the emission level for the engine in a pre-defined maneuver while keeping the engine performance in different aspects. The Genetic Algorithm (GA) is applied to find the optimized control structure. The results confirm the effectiveness of the proposed approach in emission reduction for the next generation of turbofan engines. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
7. Usefulness of signed eigenvalue/vector distributions of random tensors.
- Author
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Regalado Kloos, Max and Sasakura, Naoki
- Abstract
Quantum field theories can be applied to compute various statistical properties of random tensors. In particular, signed distributions of tensor eigenvalues/vectors are the easiest, which can be computed as partition functions of four-fermi theories. Though signed distributions are different from genuine ones because of extra signs of weights, they are expected to coincide in vicinities of ends of distributions. In this paper, we perform a case study of the signed eigenvalue/vector distribution of the real symmetric order-three random tensor. The correct critical point and the correct end in the large N limit are obtained from the four-fermi theory, for which a method using the Schwinger-Dyson equation is very efficient. Since locations of ends are particularly important in applications, such as the largest eigenvalues and the best rank-one tensor approximations, signed distributions are the easiest and highly useful through the Schwinger-Dyson method. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Barycentric Lagrange interpolation method for solving Love's integral equations.
- Author
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Shoukralla, E. S. and Ahmed, B. M.
- Subjects
INTEGRAL equations ,INTERPOLATION ,MATRICES (Mathematics) ,COLLOCATION methods ,ANALYTICAL solutions - Abstract
In this paper, we present a new simple method for solving two integral equations of Love's type that have many applications, especially in electrostatic systems. The approach of the solution is based on an innovative technique using matrix algebra for the barycentric Lagrange interpolation. The unknown function is expressed through the product of four matrices. The kernel is interpolated twice, so we get it in the product of five matrices. Additionally, we derive an equivalent linear algebraic system to the solution by substituting the matrix-vector barycentric interpolated unknown function together with the double interpolated kernel into both sides of the integral equation. Thus, there was no need to employ the collocation method. The obtained results converge strongly with the approximate analytical solutions, in addition to being uniformly approximated, continuous, and even, which proves the validity of the solution by the presented method. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
9. An integral equation approach for pricing American put options under regime-switching model.
- Author
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Zhu, Song-Ping and Zheng, Yawen
- Subjects
OPTIONS (Finance) ,INTEGRAL equations ,MATHEMATICAL decoupling ,PRICES ,DERIVATIVE securities ,PARTIAL differential equations - Abstract
Regime-switching models have been heavily studied recently, as they have some clear advantages of over other non-constant volatility model to resolve the so-called smirk effect displayed when constant volatility models are used to price financial derivatives such as options. However, due to the increased model complexity, the associated computational effort usually increases as well, particularly when they are used to price American-style options. In this paper, a novel computational approach based on integral equations is presented. A distinctive feature of our approach, in comparison with other numerical approaches, is that the coupled partial differential equations (PDEs) in a PDE system have been decoupled in the Fourier space, resulting in a completely decoupled integral equation for each economical states, and thus has greatly reduced computational effort. Some examples with preliminary results for a two-state regime-switching model are used to demonstrate our approach. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
10. The nonlinear distribution of employment across municipalities
- Author
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Prieto, Faustino, Sarabia, José María, and Calderín-Ojeda, Enrique
- Subjects
Statistics - Methodology ,Physics - Physics and Society ,00A69 - Abstract
In this paper, the nonlinear distribution of employment across Spanish municipalities is analyzed. In addition, we explore the properties of the family of generalized power law (GPL) distributions, and test its adequacy for modelling employment data. The hierarchical structure of the GPL family that includes the hierarchy of Pareto (power law) distributions is deeply studied. A new subfamily of heavy-tailed GPL distributions that is right tail equivalent to a Pareto (power law) model is derived. Our findings show on the one hand that the distribution of employment across Spanish municipalities follows a power law behavior in the upper tail and, on the other hand, the adequacy of GPL models for modelling employment data in the whole range of the distribution., Comment: This is a preprint (29 pages, 5 tables, 8 figures)
- Published
- 2018
11. Newton interpolation using ℜ-Leja sequences
- Author
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Chkifa, Moulay Abdellah
- Published
- 2022
- Full Text
- View/download PDF
12. Theoretical Aspects of a Design Method for Programmable NMR Voters
- Author
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Hadzieva, Elena and Simevski, Aleksandar
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing ,00A69 - Abstract
Almost all dependable systems use some form of redundancy in order to increase fault-tolerance. Very popular are the $N$-Modular Redundant (NMR) systems in which a majority voter chooses the voting output. However, elaborate systems require fault-tolerant voters which further give additional information besides the voting output, e.g., how many module outputs agree. Dynamically defining which set of inputs should be considered for voting is also crucial. Earlier we showed a practical implementation of programmable NMR voters that self-report the voting outcome and do self-checks. Our voter design method uses a binary matrix with specific properties that enable easy scaling of the design regarding the number of voter inputs N. Thus, an automated construction of NMR systems is possible, given the basic module and arbitrary redundancy $N$. In this paper we present the mathematical aspects of the method, i.e., we analyze the properties of the matrix that characterizes the method. We give the characteristic polynomials of the properly and erroneously built matrices in their explicit forms. We further give their eigenvalues and corresponding eigenvectors, which reveal a lot of useful information about the system. At the end, we give relations between the voter outputs and eigenpairs., Comment: 11 pages, 3 figures
- Published
- 2015
13. Sensitivity analysis of queueing models based on polynomial chaos approach
- Author
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Ameur, Lounes and Bachioua, Lahcene
- Published
- 2021
- Full Text
- View/download PDF
14. Simulating human interactions in supermarkets to measure the risk of COVID-19 contagion at scale
- Author
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Plata, Serge, Sarma, Sumanas, Lancelot, Melvin, Bagrova, Kristine, and Romano-Critchley, David
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing ,Computer Science - Multiagent Systems ,00A69 - Abstract
Taking the context of simulating a retail environment using agent based modelling, a theoretical model is presented that describes the probability distribution of customer "collisions" using a novel space transformation to the Torus $Tor^2$. A method for generating the distribution of customer paths based on historical basket data is developed. Finally a calculation of the number of simulations required for statistical significance is developed. An implementation of this modelling approach to run simulations on multiple store geometries at industrial scale is being developed with current progress detailed in the technical appendix., Comment: 23 pages, 11 figures
- Published
- 2020
15. Torsional waves propagation in an initially stressed dissipative cylinder
- Author
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Selim, M. M.
- Subjects
Mathematical Physics ,General Relativity and Quantum Cosmology ,00A69 - Abstract
The present paper has been framed to show the effect of damping on the propagation of torsional waves in an initially stressed, dissipative, incompressible cylinder of infinite length. A governing equation has been formulated on Biot's incremental deformation theory. The velocities of torsional waves are obtained as complex ones, in which real part gives the phase velocity of propagation and corresponding imaginary part gives the damping. The study reveals that the damping of the medium has strong effect in the propagation of torsional wave. Since every medium has damping so it is more realistic to use the damped wave equation instead of the undamped wave equation. The study also shows that the velocity of propagation of such waves depend on the presence of initial stress. The influences of damping and initial stresses are shown separately., Comment: 9 pages; http://faculty.ksu.edu.sa/mmselim
- Published
- 2009
16. Compressed Sensing with Cross Validation
- Author
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Ward, Rachel
- Subjects
Mathematics - Numerical Analysis ,00A69 - Abstract
Compressed Sensing decoding algorithms can efficiently recover an N dimensional real-valued vector x to within a factor of its best k-term approximation by taking m = 2klog(N/k) measurements y = Phi x. If the sparsity or approximate sparsity level of x were known, then this theoretical guarantee would imply quality assurance of the resulting compressed sensing estimate. However, because the underlying sparsity of the signal x is unknown, the quality of a compressed sensing estimate x* using m measurements is not assured. Nevertheless, we demonstrate that sharp bounds on the error || x - x* ||_2 can be achieved with almost no effort. More precisely, we assume that a maximum number of measurements m is pre-imposed; we reserve 4log(p) of the original m measurements and compute a sequence of possible estimates (x_j)_{j=1}^p to x from the m - 4log(p) remaining measurements; the errors ||x - x*_j ||_2 for j = 1, ..., p can then be bounded with high probability. As a consequence, numerical upper and lower bounds on the error between x and the best k-term approximation to x can be estimated for p values of k with almost no cost. Our observation has applications outside of compressed sensing as well., Comment: title changed; paper rewritten to include more examples 18 pages, one figure
- Published
- 2008
17. An inversion formula for the horizontal conical Radon transform.
- Author
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Nguyen, Duy N. and Nguyen, Linh V.
- Abstract
In this paper, we consider the conical Radon transform on all one-sided circular cones in R 3 with horizontal central axis whose vertices are on a vertical line. We derive an explicit inversion formula for such transform. The inversion makes use of the vertical slice transform on a sphere and V-line transform on a plane. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
18. Closed Form Approximations For The Three Body Problem
- Author
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Mehmood, A. B., Shah, U. A., and Shabbir, G.
- Subjects
Mathematical Physics ,00A69 - Abstract
In this paper, an approach is developed to solve the three body problem involving masses which posses spherical symmetry. The problem dates back to the times of Poincare, and is undoubtedly one of the oldest of unsolved problems of classical mechanics. The Poincares Dictum comprehensively proves that the problem is truly insolvable as a result of the nature of the instabilities involved. We therefore refute the idea of finding exact solutions. Instead, we develop closed form analytical approximations in place of exact solutions. We will solve the problem for the case when all the masses involved have spherically symmetric mass distributions. The method of solution would include the use of a single mass to replicate the effect of two individual masses on each body. The derivation of solutions will involve the use of the Lamberts wave function and the solution will comprise of the position vectors expressed as explicit time functions., Comment: 18 pages, 5 figures
- Published
- 2004
19. Deep Learning for Real-Time Crime Forecasting and Its Ternarization
- Author
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Wang, Bao, Yin, Penghang, Bertozzi, Andrea Louise, Brantingham, P. Jeffrey, Osher, Stanley Joel, and Xin, Jack
- Published
- 2019
- Full Text
- View/download PDF
20. When logic lays down the law
- Author
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Jespersen, Bjørn, Borges, Ana de Almeida, Tierz, Jorge del Castillo, Rodríguez, Juan José Conejero, Adamson, Eric Sancho, Sánchez, Aleix Solé, Pona, Nika, and Joosten, Joost J.
- Subjects
Computer Science - Artificial Intelligence ,Computer Science - Computation and Language ,00A69 - Abstract
We analyse so-called computable laws, i.e., laws that can be enforced by automatic procedures. These laws should be logically perfect and unambiguous, but sometimes they are not. We use a regulation on road transport to illustrate this issue, and show what some fragments of this regulation would look like if rewritten in the image of logic. We further propose desiderata to be fulfilled by computable laws, and provide a critical platform from which to assess existing laws and a guideline for composing future ones., Comment: 26 pages
- Published
- 2018
21. Measuring Political Gerrymandering
- Author
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Tapp, Kristopher
- Subjects
Physics - Physics and Society ,00A69 - Abstract
In 2016, a Wisconsin court struck down the state assembly map due to unconstitutional gerrymandering. If this ruling is upheld by the Supreme Court's pending 2018 decision, it will be the fist successful political gerrymandering case in the history of the United States. The efficiency gap formula made headlines for the key role it played in this case. Meanwhile, the mathematics is moving forward more quickly than the courts. Even while the country awaits the Supreme Court decision, improved versions of the efficiency gap formula have been proposed, analyzed and compared. Since much of the relevant literature appears (or will appear) in law journals, we believe that the general math audience might find benefit in a concise self-contained overview of this application of mathematics that could have profound consequences for our democracy.
- Published
- 2018
22. Effect of the Reynolds number on flow bifurcations and eddy genesis in a lid-driven sectorial cavity.
- Author
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Bilgil, Halis and Gürcan, Fuat
- Abstract
This paper presents the two-dimensional (2D) steady incompressible flow in a lid-driven sectorial cavity. In order to analyze the flow structures, the 2D Navier-Stokes equations are solved by using the finite element method. Different cases of the cavity aspect ratio A and three cases of the speed ratios $$(S=-1,0,1)$$ of the upper and the lower lids are considered. The finite element formulation for the governing equations is adopted via the velocity-pressure formulation. By varying A for each S, the effect of the Reynolds number on the streamline patterns and their bifurcations are investigated in range $$Re\in [0,200]$$ . A comparison between the obtained results and some earlier studies is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
23. A LOGNORMAL MODEL FOR DEMAND FORECASTING IN THE NATIONAL ELECTRICITY MARKET.
- Author
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MAISANO, J., RADCHIK, A., and LING, T.
- Subjects
SUPPLY & demand ,STATISTICS ,ECONOMIC demand ,SCIENTIFIC method - Abstract
Many electricity market participants have a requirement to calculate the probabilistic risk measures, such as earnings at risk (EaR) and value at risk (VaR), for compliance reporting purposes. This requirement is currently hindered by the lack of analytical representations for forecasts of demand (load) and price curves; this motivates numerical simulation and models that need extensive calibration. In this paper, we derive an analytical representation of a state demand forecast which is the aggregated usage of all electricity consumers in a particular region (such as New South Wales or Victoria). We have used two probabilistic benchmarks from the Australian energy market operator as input, which are expressed as forecasted probability of exceedance.Due to a number of considerations, including asymmetry of these quantiles with respect to the median, we have selected a series of truncated lognormal distributions with two parameters. The procedure of finding these parameters has been reduced to solving (for every half-hour) a single nonlinear equation. As a result, the two-year half-hourly forecast (expected curve) and demand volatility are found by explicit integration with the set of derived distributions. We have also tested an alternative method based on simplifying assumptions; using a nontruncated lognormal distribution, we found that under the test conditions this method produces an identical forward load and volatility curve. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
24. Anisotropic Elastic Strain-Gradient Continuum from the Macro-Scale to the Granular Micro-Scale.
- Author
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Pirmoradi, P., Suiker, A. S. J., and Poorsolhjouy, P.
- Subjects
PROBABILITY density function ,ANISOTROPY ,MICROMECHANICS ,MICROSTRUCTURE ,SYMMETRY - Abstract
A multi-scale framework is constructed for the computation of the stiffness tensors of an elastic strain-gradient continuum endowed with an anisotropic microstructure of arbitrarily-shaped particles. The influence of microstructural features on the macroscopic stiffness tensors is demonstrated by comparing the fourth-order, fifth-order and sixth-order stiffness tensors obtained from macro-scale symmetry considerations to the stiffness tensors deduced from homogenizing the elastic response of the granular microstructure. Special attention is paid to systematically relating the particle properties to the probability density function describing their directional distribution, which allows to explicitly connect the level of anisotropy of the particle assembly to local variations in particle stiffness and morphology. The applicability of the multi-scale framework is exemplified by computing the stiffness tensors for various anisotropic granular media composed of equal-sized spheres. The number of independent coefficients of the homogenized stiffness tensors appears to be determined by the number of independent microstructural parameters, which is equal to, or less than, the number of independent stiffness coefficients following from macro-scale symmetry considerations. Since the modelling framework has a general character, it can be applied to different higher-order granular continua and arbitrary types of material anisotropy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Non-linear anti-symmetric shear motion: a comparative study of non-homogeneous and homogeneous plates
- Author
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Demirkuş, Dilek
- Published
- 2020
- Full Text
- View/download PDF
26. Sets with Dependent Elements: A Formalization of Castoriadis’ Notion of Magma
- Author
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Tzouvaras, Athanassios
- Published
- 2024
- Full Text
- View/download PDF
27. Observability and sensitivity analysis of lightcurve measurement models for use in space situational awareness.
- Author
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Subbarao, K. and Henderson, L.
- Subjects
POSE estimation (Computer vision) ,SITUATIONAL awareness ,SINGULAR value decomposition ,SENSITIVITY analysis ,ANGULAR velocity ,KALMAN filtering - Abstract
This paper deals with the observability and sensitivity analysis of the lightcurve measurement for use in the estimation of instantaneous pose (orientation) and shape geometry. Since several reflectance models exist that are typically used in obtaining a synthetic lightcurve measurement, they are compared to assess the observability or/and 'sensitivity' to determine the 'best model' for use. These measurement models are nonlinear with implicit and non-trivial dependency on the states; a numerical Jacobian as well as an unscented Kalman filter derived observation matrix are synthesized for each choice of the measurement model and compared. As the linearization is about an attitude (orientation) trajectory, distinct cases are considered to elaborate the results. For the cases evaluated here, it is shown that the attitude and shape/size can indeed be estimated from the lightcurve, but this is also dependent upon the initial conditions (subsequent attitude trajectory). Linear observability analysis of a discretized system is also performed with respect to the attitude states and shape/size parameters using the singular value decomposition of the observability matrix synthesized for a batch of measurements. The results are summarized for various initial conditions of the resident space object's attitude and angular velocity states. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. A distributed and parallel unite and conquer method to solve sequences of non-Hermitian linear systems.
- Author
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Wu, Xinzhe and Petiton, Serge G.
- Abstract
Many problems in science and engineering often require to solve a long sequence of large-scale non-Hermitian linear systems with different right-hand sides (RHSs) but a unique operator. Efficiently solving such problems on extreme-scale platforms requires the minimization of global communications, reduction of synchronization and promotion of asynchronous communications. Unite and Conquer GMRES/LS-ERAM (UCGLE) method (Wu and Petiton, in Proceedings of the International Conference on High Performance Computing in Asia-Pacific Region. ACM, New York, pp 36–46, 10.1145/3149457.3154481, 2018) is a suitable candidate with the reduction of global communications and the synchronization points of all computing units. It consists of three computing algorithms with asynchronous communications that allow the use of approximated eigenvalues to accelerate the convergence of solving linear systems and to improve fault tolerance. In this paper, we extend both the mathematical model and the implementation of UCGLE method to adapt to solve sequences of linear systems. The eigenvalues obtained in solving previous linear systems by UCGLE can be recycled, improved on the fly and applied to construct a new initial guess vector for subsequent linear systems, which can achieve a continuous acceleration to solve linear systems in sequence. Numerical experiments using different test matrices to solve sequences of linear systems on supercomputer Tianhe-2 indicate a substantial decrease in both computation time and iteration steps when the approximated eigenvalues are recycled to generate the initial guess vectors. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Using hybrid GA-PSO algorithm to solve problem in machine scheduling.
- Author
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Khraibet, Tahani Jabbar and Ghafil, Wisam Kamil
- Subjects
- *
PRODUCTION scheduling , *PARTICLE swarm optimization , *FLOW shop scheduling , *GENETIC algorithms , *PROBLEM solving , *FLOW shops - Abstract
In this paper, we describe new hybrid genetic algorithm and particle swarm optimization to solve the sum of earliness and the number of tardy job on two-machines flow shop schedule problem is NP- hard. The study discusses a hybrid genetic algorithm and particle swarm optimization (HGA-PSO) to tackle the presented mission. Extensive experiments, based on computers, suggest that the proposed mathematical models are efficient in solving flow shop problems with GA solved to n = 3000 while PSO solved to n = 500 job. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
30. Bioinspired Sensory Systems for Shear Flow Detection.
- Author
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Colvert, Brendan, Chen, Kevin, and Kanso, Eva
- Subjects
AQUATIC organisms ,SHEAR flow ,COPEPODA ,HYDRODYNAMICS ,BIOSENSORS - Abstract
Aquatic organisms such as copepods exhibit remarkable responses to changes in ambient flows, especially shear gradients, when foraging, mating and escaping. To accomplish these tasks, the sensory system of the organism must decode the local sensory measurements to detect the flow properties. Evidence suggests that organisms sense differences in the hydrodynamic signal rather than absolute values of the ambient flow. In this paper, we develop a mathematical framework for shear flow detection using a bioinspired sensory system that measures only differences in velocity. We show that the sensory system is capable of reconstructing the properties of the ambient shear flow under certain conditions on the flow sensors. We discuss these conditions and provide explicit expressions for processing the sensory measurements and extracting the flow properties. These findings suggest that by combining suitable velocity sensors and physics-based methods for decoding sensory measurements, we obtain a powerful approach for understanding and developing underwater sensory systems. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
31. Efficient processing of intelligent probabilistic collision detection queries.
- Author
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Huang, Yuan-Ko
- Subjects
COLLISION detection (Computer animation) ,COMPUTER-generated imagery ,MOBILE communication systems ,TELECOMMUNICATION systems ,NUMERICAL integration - Abstract
A new type of the spatio-temporal queries is the Intelligent Probabilistic Collision Detection Query ( IPCDQ for short). In this paper, we focus on efficiently processing the IPCDQ on moving objects with uncertainty. Given two sets O and Q of objects, each of which moves with uncertain speed and direction, a time instant t, and a probability threshold P, the IPCDQ returns each pair of objects ( o, q) (where $$o \in O$$ and $$q \in Q$$ ), whose probability of colliding with each other is greater than or equal to P at time t. The pairs of objects satisfying the IPCDQ are termed the collision-possible pairs (or CPPs for short). We utilize a $$R^{lsd}$$ -tree, in which the spatially proximate objects with similar uncertain speeds and directions are grouped together, to effectively manage the moving objects in O. Similarly, a $$R^{lsd}$$ -tree is used to index the moving objects in Q. Then, with the two $$R^{lsd}$$ -trees for O and Q, respectively, we develop the specialized index traversals combined with three pruning criteria, the location-pruning criterion, the angle-pruning criterion, and the speed-pruning criterion to efficiently determine the objects that may collide with each other. Besides, to provide the more useful information to the user, we propose a probability model to quantify the possibility of each object pair being the query result. Comprehensive experiments demonstrate the efficiency and the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
32. Sharp Weighted Korn and Korn-Like Inequalities and an Application to Washers.
- Author
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Harutyunyan, Davit
- Subjects
ELASTICITY ,CARTESIAN coordinates ,INTEGRAL inequalities ,WASHERS (Fasteners) - Abstract
In this paper we prove asymptotically sharp weighted 'first-and-a-half' $2D$ Korn and Korn-like inequalities with a singular weight occurring from Cartesian to cylindrical change of variables. We prove some Hardy and the so-called 'harmonic function gradient separation' inequalities with the same singular weight. Then we apply the obtained $2D$ inequalities to prove similar inequalities for washers with thickness $h$ subject to vanishing Dirichlet boundary conditions on the inner and outer thin faces of the washer. A washer can be regarded in two ways: As the limit case of a conical shell when the slope goes to zero, or as a very short hollow cylinder. While the optimal Korn constant in the first Korn inequality for a conical shell with thickness $h$ and with a positive slope scales like $h^{1.5}$ , e.g., (Grabovsky and Harutyunyan in , 2016), the optimal Korn constant in the first Korn inequality for a washer scales like $h^{2}$ and depends only on the outer radius of the washer as we show in the present work. The Korn constant in the first and a half inequality scales like $h$ and depends only on $h$ . The optimal Korn constant is realized by a Kirchhoff Ansatz. This results can be applied to calculate the critical buckling load of a washer under in plane loads, e.g., (Antman and Stepanov in J. Elast. 124(2):243-278, 2016). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
33. Steady-state dc voltage ripple discrete analysis of PFC with estimated second-order harmonic compensation for achieving satisfactory performance.
- Author
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Long, Yingwen, Sun, Yuhong, and Zhang, Wei
- Subjects
POWER factor measurement ,HARMONIC analysis (Mathematics) ,ELECTRIC potential - Abstract
In the conventional output voltage feedback loop design of an active power factor corrector (PFC), the bandwidth of the loop is limited to a frequency significantly lower than the input line voltage frequency. This is due to the fact that the compensator placed in the outputvoltage feedback loop is usually designed to have a narrow bandwidth in order to filter the voltage ripple of twice the line frequency coming from the PFC output dc voltage. This feedback loop is designed with this filtering effect because a relatively high ripple voltage would cause considerable distortion in the reference of the line current feedback loop. However, a low bandwidth voltage feedback loop would bring poor dynamic response which usually causes large overshoots and dips during load transient change. Therefore, a compromise is generally made for the traditional design of the output voltage feedback loop, which leads to an issue that both the steady and the dynamic behaviours of the PFC are not optimal. In this paper, mathematic model of the steady behaviour of a PFC with voltage ripple in the output-voltage feedback loop is studied using two parameters: the amplitude of the relative voltage ripple on the control output signal and its phase lag angle of the voltage feedback loop. On the basis of the analysis, a second-order voltage harmonic injection to the output-voltage feedback loop is used to eliminate the voltage harmonic components from the voltage feedback loop. Finally, the feasibility of the proposed second-order harmonic injection method was verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. The circular division of the factor group when r is an odd number.
- Author
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Jabir, Naba Hasoon and Abass, Rajaa Hassan
- Subjects
- *
ORDERED groups , *ODD numbers , *INTEGERS , *QUATERNIONS - Abstract
The benefit of this paper is to find the circular divison of the factor group when r is an odd number, where Q2r is denoted to Quaternion group of order 4r, such that for each positive integer r, there are two generators a and b for Q2r satisfies Q2r = {ah bk, 0 ≤ h ≤ 2r − 1, k = 0, 1} which has the following properties {a2r = b4 = I, barb−1 = a−r}. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
35. Impacts of information propagation on epidemic spread over different migration routes.
- Author
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Wang, Bing, Gou, Min, and Han, Yuexing
- Abstract
Information propagation driven by the epidemic may cause individuals awareness to change their behavior to prevent themselves from being infected, as we observed in reality that aware individuals often migrate away from infected areas. In this work, we study the coupled interaction of epidemic spreading and information propagation over a two-layer metapopulation network, where aware and unaware individuals separately take different migration routes, and mainly explore how individual migration route affects the epidemic spreading. Combined with the transition probability tree of individual states, we use Markovian chain approach to derive the epidemic threshold for the proposed model. Through numerous Monte Carlo simulations, we verify the accuracy of the Markovian equations for the prediction of epidemic dynamics. The results show that the role of information transmission in suppressing the epidemic is limited. Further increase in the information transmission rate beyond some critical value will no longer affect the epidemic. Detailed analysis of information propagation has to consider the migration route of individuals, especially the aware individuals, and their mobility frequency. In addition, the initial population distribution is also a fundamental factor for the epidemic dynamic. With a heterogeneous population distribution, frequent mobility of individuals would delay the epidemic spread, while with the homogeneous population distribution, it does not. The study of the coupled interaction between epidemic and information over separate migration routes provides helpful guidance for the intervention of epidemic in reality. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. Conjecture concerning a completely monotonic function
- Author
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Shemyakova, E., Khashin, S. I., and Jeffrey, D. J.
- Subjects
Mathematics - Classical Analysis and ODEs ,00A69 - Abstract
Based on a sequence of numerical computations, a conjecture is presented regarding the class of functions $H(x;a)=\exp(a)-(1+a/x)^x$, and the open problem of determining the values of $a$ for which the functions are completely monotonic with respect to $x$. The critical value of $a$ is determined here to sufficient accuracy to show that it is not a simple symbolic quantity., Comment: accepted for publication in Computers and Mathematics with Applications
- Published
- 2010
37. Infinitesimals without Logic
- Author
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Giordano, Paolo
- Subjects
Mathematical Physics ,00A69 ,00A79 ,03H10 - Abstract
We introduce the ring of Fermat reals, an extension of the real field containing nilpotent infinitesimals. The construction takes inspiration from Smooth Infinitesimal Analysis (SIA), but provides a powerful theory of actual infinitesimals without any need of a background in mathematical logic. In particular, on the contrary with respect to SIA, which admits models only in intuitionistic logic, the theory of Fermat reals is consistent with classical logic. We face the problem to decide if the product of powers of nilpotent infinitesimals is zero or not, the identity principle for polynomials, the definition and properties of the total order relation. The construction is highly constructive, and every Fermat real admits a clear and order preserving geometrical representation. Using nilpotent infinitesimals, every smooth functions becomes a polynomial because in Taylor's formulas the rest is now zero. Finally, we present several applications to informal classical calculations used in Physics: now all these calculations become rigorous and, at the same time, formally equal to the informal ones. In particular, an interesting rigorous deduction of the wave equation is given, that clarifies how to formalize the approximations tied with Hook's law using this language of nilpotent infinitesimals., Comment: The first part of the preprint is taken directly form arXiv:0907.1872 The second part is new and contains a list of examples
- Published
- 2009
- Full Text
- View/download PDF
38. Influence of seasonal factors in the earned value of construction
- Author
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Ruiz-Fernández Juan Pedro, Benlloch Javier, López Miguel A., and Valverde-Gascueña Nelia
- Subjects
seasonal factors ,earned value ,cash flows ,construction ,00a69 ,62-07 ,62p30 ,Mathematics ,QA1-939 - Abstract
The objectives in each construction process can be multiple. However, the constructions have to be carried out under some restrictions concerning price and terms. They constitute some strategic and interdependent goals. In other words, “time is money”. Several papers support that seasonal effects influence the execution rate of construction. Thus, most of them try to improve the forecasts by evaluating and joining them to the planning, although always measuring their influence indirectly. In this paper, we suggest a methodology to directly measure the influence of the seasonal factors as a whole over the earned value of construction. Additionally, we apply it to a certain case study regarding the subsidised housing of public promotion in the Castilla-La Mancha region (Spain). It is worth mentioning that our results are clarified: we have calculated the average monthly production for each month a year with respect to the annual monthly mean. Moreover, the differences regarding the average monthly production we have contributed are quite significant, and hence they have to be taken into account for each earned value forecast so that a project becomes reliable.
- Published
- 2019
- Full Text
- View/download PDF
39. The electronic cash system based on non-interactive zero-knowledge proofs.
- Author
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Zhou, Fucai, Li, Yuxi, Zhou, Qingshi, Miao, Jingwei, and Xu, Jian
- Subjects
ELECTRONIC money ,INFORMATION & communication technologies ,MATHEMATICAL proofs ,SYSTEMS theory ,COMPARATIVE studies - Abstract
Electronic cash is an electronic form of currency, which allows the cash transactions over communication networks under privacy protections. However, it still has some aspects that have not been well studied. Known constructions suffer from at least one of the following limitations: (1) relying on a random oracle, (2) not supporting multiple bank setting and users dynamically joining or (3) prohibitively expensive. In this paper, we propose a new electronic cash system that avoids all these limitations. In other words, our system is anonymous against chosen-ciphertext attack (CCA) in the standard model, and supports multiple banks enrolling and users dynamically joining, which is achieved by the utilization of non-interactive zero-knowledge proof and dynamic group signature. Finally, in the standard model, a formal security proof is given to claim that our system has CCA anonymity, unforgeability, traceability and no double-spending. Compared with the existing systems, ours has advantages of both the efficiency and security. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
40. Closed Form Approximations for the Trajectories of the Three Body Problem
- Author
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Mehmood, AbuBakr, Shah, Syed Umer Abbas, and Shabbir, Ghulam
- Subjects
Mathematical Physics ,00A69 - Abstract
The problem of describing the free motions of three gravitating bodies under each others gravitational influence is one of the oldest of unsolved problems of classical mechanics. Henry Poincare proved in his dictum that due to the nature of the instabilities involved in the problem, it could not be solved. Yet closed form approximations for the problem can be found and it is on these lines that we will explore the problem. It will be shown that closed form approximations for the associated trajectories can be found., Comment: 14 pages, 4 figures
- Published
- 2005
41. A Generalized approach for Approximate Solutions to the N Body Problem
- Author
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Mehmood, AbuBakr, Shah, Syed Umer Abbas, and Shabbir, Ghulam
- Subjects
Mathematical Physics ,00A69 - Abstract
An approach is developed to find approximate solutions to the classical Newtonian problem of N bodies. Sets of N gravitating bodies having spherically symmetric mass distributions, small angular velocities (< 1 rad/s) and bounded position vectors have been taken into consideration. In addition, it is assumed that the masses form an isolated system in free space and perform free gravitating motion. Although the problem is not exactly solvable, a new approach will be developed to find approximate solutions using N number of two body motion analogues., Comment: 10 pages, 3 figures
- Published
- 2005
42. A Generalized approach for computing the trajectories associated with the Newtonian N Body Problem
- Author
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Mehmood, AbuBakr, Shah, Syed Umer Abbas, and Shabbir, Ghulam
- Subjects
Mathematical Physics ,00A69 - Abstract
The Classical Newtonian problem of describing the free motions of N gravitating bodies which form an isolated system in free space has been considered. It is well known from the Poincares Dictum that the problem is not exactly solvable. Sets of N body systems composed of masses having spherical symmetry, appropriate angular velocities (< 1 rad/s) and bounded position vectors are examined. A procedure has been developed which yields expressions approximately defining the trajectories executed by the masses., Comment: 9 Pages, 2 figures
- Published
- 2004
43. Closed Form Approximation Solutions for the Restricted Circular Three Body Problem
- Author
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Mehmood, Abu Bakr, Abbas, S. Umer, and Shabbir, Ghulam
- Subjects
Mathematical Physics ,00A69 - Abstract
An approach is developed to find approximate solutions to the restricted circular three body problem. The solution is useful in approximately describing the position vectors of three spherically symmetric masses, one of which has a much smaller mass than the other two. These masses perform free motion under each others gravitational influence. The set of solutions is found using the lamberts wave function., Comment: 18 pages, 4 figures
- Published
- 2004
44. Heuristic algorithm for solving of the graph isomorphism problem
- Author
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Faizullin, R. T. and Prolubnikov, A. V.
- Subjects
Mathematics - General Mathematics ,00A05 ,00A69 - Abstract
We consider heuristic algorithm for solving graph isomorphism problem. The algorithm based on a successive splitting of the eigenvalues of the matrices which are modifications (to positive defined) of graphs' adjacency matrices. Modification of the algorithm allows to find a solution for Frobenius problem. Formulation of the Frobenius problem is following one. Given a pair of two matrices with the same number of rows and columns. We must find out whether one of the matrix can be acquired from another by permutation of it's rows and strings or not. For example, solution of Frobenius problem can give to us efficient way for decrypting of double permutation cyphers problem for high dimension matrices.
- Published
- 2002
45. Fractional HIV infection model described by the Caputo derivative with real data
- Author
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Acay Öztürk, Bahar, Yusuf, Abdullahi, and Inc, Mustafa
- Published
- 2024
- Full Text
- View/download PDF
46. A practical application of the geometrical theory on fibered manifolds to an autonomous bicycle motion in mechanical system with nonholonomic constraints.
- Author
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Haddout, Soufiane
- Subjects
- *
NONHOLONOMIC constraints , *NONLINEAR theories , *MANIFOLDS (Mathematics) , *EQUATIONS of motion , *COMPUTER simulation - Abstract
The equations of motion of a bicycle are highly nonlinear and rolling of wheels without slipping can only be expressed by nonholonomic constraint equations. A geometrical theory of general nonholonomic constrained systems on fibered manifolds and their jet prolongations, based on so-called Chetaev-type constraint forces, was proposed and developed in the last decade by O. Krupková (Rossi) in 1990’s. Her approach is suitable for study of all kinds of mechanical systems-without restricting to Lagrangian, time-independent, or regular ones, and is applicable to arbitrary constraints (holonomic, semiholonomic, linear, nonlinear or general nonholonomic). The goal of this paper is to apply Krupková’s geometric theory of nonholonomic mechanical systems to study a concrete problem in nonlinear nonholonomic dynamics, i.e., autonomous bicycle. The dynamical model is preserved in simulations in its original nonlinear form without any simplifying. The results of numerical solutions of constrained equations of motion, derived within the theory, are in good agreement with measurements and thus they open the possibility of direct application of the theory to practical situations. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. Precision Machining Technology of Jewelry on CNC Machine Tool Based on Mathematical Modeling
- Author
-
Qian Nianhua and Zhou Ningrui
- Subjects
cnc machine tools ,simulation manufacturing ,five-axis linkage equation ,solid modeling ,precision jewelry processing ,00a69 ,Mathematics ,QA1-939 - Abstract
This article establishes the actual movement mathematical model of CNC machine tools for the precision processing of jewelry. Through analyzing the general geometric error analysis model of CNC machine tools with less than five axes and the method of solving precision CNC instructions, the operating principle of the CNC machine tools is studied. At the same time, we use a transformation matrix to express the relationship between the various moving bodies. The article abstracts the complex motion relationship between entities as the relationship between mathematical matrices. The experimental results show that the theoretical method proposed in this paper can increase the machining accuracy of the machine tool by more than 50%.
- Published
- 2023
- Full Text
- View/download PDF
48. Extremal {p,q}-Animals.
- Author
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Malen, Greg, Roldán, Érika, and Toalá-Enríquez, Rosemberg
- Subjects
HYPERBOLIC geometry ,PLANE geometry ,ZOOLOGICAL nomenclature ,TESSELLATIONS (Mathematics) ,GEOMETRIC shapes ,POLYGONS - Abstract
An animal is a planar shape formed by attaching congruent regular polygons along their edges. Usually, these polygons are a finite subset of tiles of a regular planar tessellation. These tessellations can be parameterized using the Schläfli symbol { p , q } , where p denotes the number of sides of the regular polygon forming the tessellation and q is the number of edges or tiles meeting at each vertex. If (p - 2) (q - 2) > 4 , = 4 , or < 4 , then the tessellation corresponds to the geometry of the hyperbolic plane, the Euclidean plane, or the sphere, respectively. In 1976, Harary and Harborth studied animals defined on regular tessellations of the Euclidean plane, finding extremal values for their vertices, edges, and tiles, when any one of these parameters is fixed. They named animals attaining these extremal values as extremal animals. Here, we study hyperbolic extremal animals. For each { p , q } corresponding to a hyperbolic tessellation, we exhibit a sequence of spiral animals and prove that they attain the minimum numbers of edges and vertices within the class of animals with n tiles. We also give the first results on enumeration of extremal hyperbolic animals by finding special sequences of extremal animals that are unique extremal animals, in the sense that any animal with the same number of tiles which is distinct up to isometries cannot be extremal. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. A Hint on the Localization of the Buckling Deformation at Vanishing Curvature Points on Thin Elliptic Shells.
- Author
-
Harutyunyan, Davit
- Subjects
CURVATURE ,DEFORMATIONS (Mechanics) ,STRUCTURAL analysis (Engineering) - Abstract
The general theory of slender structure buckling by Grabovsky and Truskinovsky (Cont. Mech. Thermodyn. 19(3–4):211-243, 2007), (later extended in J. Nonlinear Sci. 26(1):83–119, 2016 by Grabovsky and the author), predicts that the critical buckling load of a thin shell under dead loading is closely related to the Korn's constant (in Korn's first inequality) of the shell under the Dirichlet boundary conditions resulting from the loading program. It is known that under zero Dirichlet boundary conditions on the thin part of the boundary of positive, negative, and zero (one principal curvature vanishing, and one apart from zero) Gaussian curvature shells, the optimal Korn constant in Korn's first inequality scales like the thickness to the power of −1, − 4 / 3 , and − 3 / 2 respectively. In this work we analyse the scaling of the optimal constant in Korn's first inequality for elliptic shells that contain a finite number of points where both principal curvatures vanish. We prove that the presence of at least one such point on the shell leads to the scaling drop from the thickness to the power of −1 to the thickness to the power of − 3 / 2 . To our best knowledge, this is the first result in the direction for constant-sign curvature shells, that do not contain a developable region. In addition, under the assumption that a suitable trivial branch exists, we prove that in fact the buckling deformation of such shells under dead loading, should be localized at the vanishing curvature points, as the shell thickness h goes to zero. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Recovery of Atomic Measures on the Unit Sphere.
- Author
-
Filbir, Frank, Schröder, Kristof, and Veselovska, Anna
- Subjects
SPHERICAL harmonics ,SPHERES ,CONCRETE analysis - Abstract
We study the problem of recovering an atomic measure on the unit 2-sphere S 2 given finitely many moments with respect to spherical harmonics. The analysis relies on the formulation of this problem as an optimization problem on the space of bounded Borel measures on S 2 as it was considered by Y. de Castro & F. Gamboa (J. Math. Anal. Appl. 395(1):336–354, 2012) and E. Candés & C. Fernandez-Granda (J. Fourier Anal. Appl. 19(6):1229–1254, 2013). We construct a dual certificate using a kernel given in an explicit form and make a concrete analysis of the interpolation problem. Numerical examples are provided and analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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