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IEEE Workshop on Machine Learning for Signal Processing

作者： Kincaid MacDonald Dhananjay Bhaskar Guy Thampakkul Nhi Nguyen Joia Zhang Michael Perlmutter Ian Adelstein Smita Krishnaswamy Department of Mathematics Yale University Department of Genetics Yale School of Medicine Department of Computer Science Yale University Department of Mathematics Pomona College Applied Mathematics Program Yale University Department of Statistics University of Washington Department of Mathematics Boise State University Computational Biology and Bioinformatics Program Yale University

We consider the problem of embedding point cloud data sampled from an underlying manifold with an associated flow or velocity. Such data arises in many contexts where static snapshots of dynamic entities are measured, including in high-throughput biology such as single-cell transcriptomics. Existing embedding techniques either do not utilize velocity information or embed the coordinates and velocities independently, i.e., they either impose velocities on top of an existing point embedding or embed points within a prescribed vector field. Here we present FlowArtist, a neural network that embeds points while jointly learning a vector field around the points. The combination allows FlowArtist to better separate and visualize velocity-informed structures. Our results, on toy datasets and single-cell RNA velocity data, illustrate the value of utilizing coordinate and velocity information in tandem for embedding and visualizing high-dimensional data.

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Gaussian Process Port-Hamiltonian Systems: Bayesian Learning with Physics Prior

arXiv

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arXiv 2023年

作者： Beckers, Thomas Seidman, Jacob Perdikaris, Paris Pappas, George J. Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States graduate program in Applied Mathematics and Computational Science University of Pennsylvania PhiladelphiaPA19104 United States Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA19104 United States

Data-driven approaches achieve remarkable results for the modeling of complex dynamics based on collected data. However, these models often neglect basic physical principles which determine the behavior of any real-world system. This omission is unfavorable in two ways: The models are not as data-efficient as they could be by incorporating physical prior knowledge, and the model itself might not be physically correct. We propose Gaussian Process Port-Hamiltonian systems (GP-PHS) as a physics-informed Bayesian learning approach with uncertainty quantification. The Bayesian nature of GP-PHS uses collected data to form a distribution over all possible Hamiltonians instead of a single point estimate. Due to the underlying physics model, a GP-PHS generates passive systems with respect to designated inputs and outputs. Further, the proposed approach preserves the compositional nature of Port-Hamiltonian systems. © 2023, CC BY-NC-ND.

关键词： Hamiltonians

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Thermal analysis of ternary hybrid nanofluid flow in convergent/divergent channel using Box-Behnken design of response surface methodology

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Results in Physics 2025年 74.0卷

作者： Mahariq, Ibrahim Mohana, C.M. Kumar, B. Rushi Mohamed, Kezzar SARI, Mohamed Rafik El-Wahed Khalifa, Hamiden Abd Nagarathnam, Sunitha University College Korea University Seoul 02481 South Korea Najjad Zeenni Faculty of Engineering Al Quds University Jerusalem Palestine Department of Medical Research China Medical University Hospital China Medical University Taichung Taiwan Applied Science Research Center Applied Science Private University Amman Jordan GUST Engineering and Applied Innovation Research Center (GEAR) Gulf University for Science and Technology Mishref Kuwait Department of Mathematics School of Advanced Sciences Vellore Institute of Technology Tamil Nadu Vellore India Materials and Energy Engineering Laboratory (LMGE) Technology Department Faculty of Technology 20 Aout 1955 University of Skikda PO Box 26 Skikda 21000 Algeria Mechanics of Materials and Plant Maintenance Research Laboratory (LR3MI) Mechanical Engineering Department Faculty of Engineering Badji Mokhtar University of Annaba (UBMA) PO Box 12 Annaba 23052 Algeria Department of Operations and Management Research Faculty of Graduate Studies for Statistical Research Cairo University Giza 12613 Egypt Centre for Research in Computational and Applied Mechanics University of Cape Town Rondebosch 7701 South Africa

Convergent/divergent channels represent a critical advancement in thermal management systems, offering enhanced heat transfer capabilities through geometrically optimized flow paths. This study investigates the thermal and hydrodynamic characteristics of UO₂-ZnO-Fe₃O₄/EG-water ternary hybrid nanofluid in rotating convergent/divergent channels with magnetohydrodynamic and radiation effects, a critical area for enhancing heat transfer efficiency in modern thermal management systems. Employing the Runge-Kutta-Fehlberg method coupled with a Box-Behnken design approach, we analyzed how key parameters affect flow behavior and heat transfer performance. The numerical simulations reveal that increasing the nanoparticle volume fraction from 0.01 to 0.06 enhances the Nusselt number by 27.3 %, while an increase in the magnetic parameter reduces the friction coefficient by 41.2 %. The Reynolds number demonstrates a strong positive correlation with the Nusselt number (R² = 0.978). Maximum heat transfer (Nu = 33.4859) achieved at: α = 1°, Re = 40, φ = 3 %, Ha = 50, Rd = 1, Kn = 0.04, De = 0.5, Ro = 50, ε = 0, λ = 0.5 whereas a minimum flow resistance (Cf = -2.60454) occurred at: α = -3°, Re = 60, φ = 6 %, Ha = 25, Rd = 1, Kn = 0, De = 0.5, Ro = 50, ε = 0.2, λ = 0.5. For the convergent channel configuration (α = -3°), the friction coefficient was 28.3 % higher than in the divergent channel (α = 5°) under identical flow conditions. This work advances the field beyond previous studies by comprehensively analyzing the synergistic effects of rotation, magnetohydrodynamic, radiation, and channel geometry on the performance of ternary hybrid nanofluids, providing crucial insights for designing more efficient thermal systems in electronics cooling, heat exchangers, and industrial processing applications. © 2025 The Authors

关键词： Box-Behnken Design Convergent/Divergent Channels Heat Transfer Enhancement Non-linear Solar Radiation Ternary Hybrid Nanofluids Variable thermal conductivity

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Dependence of the correlated-momentum patterns in double ionization on the carrier-envelope phase and intensity of a few-cycle laser pulse

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Physical Review A 2010年第6期82卷 063423-063423页

作者： G. G. Xin D. F. Ye J. Liu Key Laboratory of Cluster Science and Department of Physics School of Science Beijing Institute of Technology Beijing 100081 China Science and Technology Computation Physics Laboratory Beijing Institute of Applied Physics and Computational Mathematics Beijing 100088 China Graduate School China Academy of Engineering Physics Beijing 100088 China Center for Applied Physics and Technology Peking University Beijing 100084 China

In the present paper, we investigate the correlated electron emission of atoms irradiated by a few-cycle laser pulse, with emphasis on the correlated longitudinal momentum spectra. We find that the spectra show clear v-shaped structures, in analogy to what was observed recently in long-pulse experiments. Moreover, the patterns of the spectra depend sensitively on the carrier-envelope phase as well as the laser intensity. The v-shaped structure is more pronounced at lower and higher intensities and becomes obscure at medium intensity. At a lower intensity, upon change of the phase from 0 to π/2, the v-shaped structure shifts from the first quadrant to the third quadrant and the ratios between the double ionization yields in the first and third quadrants are found to increase by a few orders of magnitude. The semiclassical rescattering model is exploited in the preceding calculations and the underlying mechanisms are uncovered by analyzing the subcycle dynamics of classical trajectories.

关键词： Electron emission

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Relative magnetic field and slipping effect on Casson dusty fluid of two phase fluctuating flow over inclined parallel plate

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South African Journal of Chemical Engineering 2023年 44卷 135-146页

作者： khan, Dolat Kumam, Poom Kumam, Wiyada Suttiarporn, Panawan Rehman, Ali Fixed Point Research Laboratory Fixed Point Theory and Applications Research Group Center of Excellence in Theoretical and Computational Science (TaCS-CoE) Faculty of Science King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Rd. Bang Mod Bangkok Thung Khru 10140 Thailand Center of Excellence in Theoretical and Computational Science (TaCS-CoE) Faculty of Science King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Rd. Bang Mod Bangkok Thung Khru 10140 Thailand Applied Mathematics for Science and Engineering Research Unit (AMSERU) Program in Applied Statistics Department of Mathematics and Computer Science Faculty of Science and Technology Rajamangala University of Technology Thanyaburi (RMUTT) Pathum Thani 12110 Thailand Faculty of Science Energy and Environment King Mongkut's University of Technology North Bangkok Rayong Campus Rayong 21120 Thailand Special Interest Group for Modelling and Data Analytics Faculty of Ocean Engineering Technology and Informatics Universiti Malaysia Terengganu Terengganu Kuala Nerus 21030 Malaysia

Due to its significant applications in magnetic devices for cell separation, magnetic drugs for cancer tumor treatment, blood flow adjustment during surgery, magnetic endoscopy, and fluid pumping in industrial and engineering processes, magnetohydrodynamics (MHD) has a wide range of applications. Therefore, the aim of this study to investigate the Relative Magnetic Field and slipping effect on Casson dusty fluid of two-phase fluctuating flow over inclined parallel plate. More exactly, the relative magnetic phenomena are fixed relatively to the plate (MFFRP) or fixed relatively to the fluid (MFFRF). The mathematical modeling was established as the set of partial differential equations for dusty Casson fluid. Buckingham's pi theorem is used to find out the dimensionless variables, to make our system dimensionless. The solution in perturb form is to find out by incorporating Poincare–Lighthill perturbation technique (PLPT). To know in-depth different parameters the graphical results for both velocities are plotted with the help of software Mathcad- 15. It is clearly detected that the relative magnetic field performs a vital part in the fluid as well as particle motion. Moreover, the relative magnetic field play a vital role in the decreasing of skin friction of both plates. © 2023

关键词： Brinkman fluid Dust particles Fluctuating vertical plate Inclined relative magnetic field PLPT

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Quantum Interference of Glory Rescattering in Strong-Field Atomic Ionization

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Physical Review Letters 2018年第14期121卷 143201-143201页

作者： Q. Z. Xia J. F. Tao J. Cai L. B. Fu J. Liu National Laboratory of Science and Technology on Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Beijing Computational Science Research Center Beijing 100193 China School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou 221116 China Graduate School of China Academy of Engineering Physics Beijing 100193 China CAPT HEDPS and IFSA Collaborative Innovation Center of MoE Peking University Beijing 100871 China

During the ionization of atoms irradiated by linearly polarized intense laser fields, we find for the first time that the transverse momentum distribution of photoelectrons can be well fitted by a squared zeroth-order Bessel function because of the quantum interference effect of glory rescattering. The characteristic of the Bessel function is determined by the common angular momentum of a number of semiclassical paths termed as glory trajectories, which are launched with different nonzero initial transverse momenta distributed on a specific circle in the momentum plane and finally deflected to the same asymptotic momentum, which is along the polarization direction, through post-tunneling rescattering. Glory rescattering theory based on the semiclassical path-integral formalism is developed to address this effect quantitatively. Our theory can resolve the long-standing discrepancies between existing theories and experiments on the fringe location, predict the sudden transition of the fringe structure in holographic patterns, and shed light on the quantum interference aspects of low-energy structures in strong-field atomic ionization.

关键词： Atomic & molecular processes in external fields

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CAUCHY MARKOV RANDOM FIELD PRIORS FOR BAYESIAN INVERSION

arXiv

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arXiv 2021年

作者： Suuronen, Jarkko Chada, Neil K. Roininen, Lassi School of Engineering Science Lappeenranta-Lahti University of Technology PO Box 20 LappeenrantaFI-53851 Finland Applied Mathematics and Computational Science Program King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

The use of Cauchy Markov random field priors in statistical inverse problems can potentially lead to posterior distributions which are non-Gaussian, high-dimensional, multimodal and heavy-tailed In order to use such priors successfully, sophisticated optimization and Markov chain Monte Carlo (MCMC) methods are usually required In this paper, our focus is largely on reviewing recently developed Cauchy difference priors, while introducing interesting new variants, whilst providing a comparison We firstly propose a one-dimensional second order Cauchy difference prior, and construct new first and second order two-dimensional isotropic Cauchy difference priors Another new Cauchy prior is based on the stochastic partial differential equation approach, derived from Matérn type Gaussian presentation The comparison also includes Cauchy sheets Our numerical computations are based on both maximum a posteriori and conditional mean estimation We exploit state-of-the-art MCMC methodologies such as Metropolis-within-Gibbs, Repelling-Attracting Metropolis, and No-U-Turn sampler variant of Hamiltonian Monte Carlo We demonstrate the models and methods constructed for one-dimensional and two-dimensional deconvolution problems Thorough MCMC statistics are provided for all test cases, including potential scale reduction factors. Copyright © 2021, The Authors. All rights reserved.

关键词： Bayesian networks

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Fluid permeabilities of triply periodic minimal surfaces

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Physical Review E 2005年第5期72卷 056319-056319页

作者： Y. Jung S. Torquato Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

It has recently been shown that triply periodic two-phase bicontinuous composites with interfaces that are the Schwartz primitive (P) and diamond (D) minimal surfaces are not only geometrically extremal but extremal for simultaneous transport of heat and electricity. The multifunctionality of such two-phase systems has been further established by demonstrating that they are also extremal when a competition is set up between the effective bulk modulus and electrical (or thermal) conductivity of the bicontinuous composite. Here we compute the fluid permeabilities of these and other triply periodic bicontinuous structures at a porosity ϕ=1∕2 using the immersed-boundary finite-volume method. The other triply periodic porous media that we study include the Schoen gyroid (G) minimal surface, two different pore-channel models, and an array of spherical obstacles arranged on the sites of a simple cubic lattice. We find that the Schwartz P porous medium has the largest fluid permeability among all of the six triply periodic porous media considered in this paper. The fluid permeabilities are shown to be inversely proportional to the corresponding specific surfaces for these structures. This leads to the conjecture that the maximal fluid permeability for a triply periodic porous medium with a simply connected pore space at a porosity ϕ=1∕2 is achieved by the structure that globally minimizes the specific surface.

关键词： EXACT COMPUTATION FLOW SIMULATIONS COMPOSITES TRANSPORT SYSTEMS PHASES STEP

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Identification of fishing ground hotspot of traditional purse seine fisher at northern waters of Aceh - A community-based data collection approach 1

Identification of fishing ground hotspot of traditional purs...

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1st International and National Symposium on Aquatic Environment and Fisheries, INSAEF 2020

作者： Haridhi, H.A. Rizal, S. Nanda, M. Muhammad Wilson, C.R. Department of Marine Sciences Faculty of Marine and Fisheries Syiah Kuala University Banda Aceh Indonesia Marine and Fisheries Research Center Syiah Kuala University Banda Aceh Indonesia Doctoral Program of Mathematics and Applied Science Graduate School Syiah Kuala University Banda Aceh Indonesia Asian Development Bank Mandaluyong Philippines

Fishing grounds are among the most important key of information kept by the fishermen. Understanding the fishing ground locations are considered important as an evaluation of the fishing effort being reached by the fishermen as well as understanding the pressure being received to the fish stock at the surrounding water. The recent study has shown that a community-based data collection approach was found successful in recording and analyzing the fishing ground locations and its properties. One of the few projects implementing this concept is the Community-Based Bathymetric Survey (CBBS), which was realized by the Body of Rehabilitation and Reconstruction (BRR) Nanggroe Aceh Darussalam (NAD) - Nias with funding from the Asian Development Bank (ADB). As many as 151 GPS-transducer recording devices were installed to the fishermen boats along the coast of Aceh, with 45 devices were installed to the traditional purse seine fisher at the northern water of Aceh. These devices were configured to automatically record locations each time the boat moved 30 m. Other important information, such as water depth, time, speed, and sea surface temperature (SST) were recorded as well. This study aims to examine the fishing ground and its fishing hotspot of the traditional purse seine fisher in the northern waters of Aceh. The data collection was performed between June 2007 and May 2009 and gathered as many as 922 data sets consist of 6,170,648 data points, from the 45 purse seine boats. Trough the data, we are able to identify the typical fishing activities of purse seiner and as many as 1,619 data points were being detected. The results indicate that there are five main regions of the fishing ground hotspot in the northern waters of Aceh, i.e. 1. Western offshore of Lhok Nga, 2. Northern offshore of Ulee Lheue, 3. Western offshore of Aceh Islands, 4. Eastern offshore of Aceh Island, and 5. Northern offshore of Krueng Raya. Among the fishing ground hotspot analyzed, the Western offshor

关键词： Location

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Extreme ultraviolet and visible spectroscopy of promethiumlike heavy ions

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Physical Review A 2015年第2期92卷 022510-022510页

作者： Yusuke Kobayashi Kai Kubota Kazuki Omote Akihiro Komatsu Junpei Sakoda Maki Minoshima Daiji Kato Jiguang Li Hiroyuki A. Sakaue Izumi Murakami Nobuyuki Nakamura Institute for Laser Science The University of Electro-Communications Chofu Tokyo 182-8585 Japan National Institute for Fusion Science Toki Gifu 509-5292 Japan Department of Fusion Science SOKENDAI (The Graduate University for Advanced Studies) Toki Gifu 509-5292 Japan Institute of Applied Physics and Computational Mathematics Beijing 100088 China

We present extreme ultraviolet and visible spectra of promethiumlike tungsten and gold obtained with an electron beam ion trap. Although the contributions from a few charge states are involved in the spectra, the charge state of the ion assigned to the observed lines is definitely identified by the time-of-flight (TOF) analysis of the ions performed at the same time with the spectroscopic measurements. Experimental results are compared with collisional-radiative model calculations as well as previous experimental and theoretical studies. Some ambiguous identifications in the previous observations have been clarified owing to the definite identification by the TOF analysis.

关键词： HEAVY ions OPTICAL spectroscopy ULTRAVIOLET spectroscopy TUNGSTEN GOLD ELECTRON beams ION traps

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