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Probabilistic Machine Learning for Healthcare

Biomedical Data Science 2021年第1期4卷 393-415页

作者： Irene Y. Chen Shalmali Joshi Marzyeh Ghassemi Rajesh Ranganath 1Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA email: iychen@mit.edu 2Vector Institute Toronto Ontario M5G 1M1 Canada email: shalmali@vectorinstitute.ai 3Institute for Medical and Evaluative Sciences Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA 6Department of Population Health New York University Grossman School of Medicine New York NY 10016 USA 5Center for Data Science New York University New York NY 10012 USA 4Department of Computer Science Courant Institute New York University New York NY 10012 USA

Machine learning can be used to make sense of healthcare data. Probabilistic machine learning models help provide a complete picture of observed data in healthcare. In this review, we examine how probabilistic machine learning can advance healthcare. We consider challenges in the predictive model building pipeline where probabilistic models can be beneficial, including calibration and missing data. Beyond predictive models, we also investigate the utility of probabilistic machine learning models in phenotyping, in generative models for clinical use cases, and in reinforcement learning.

关键词： probabilistic modeling health electronic health records machine learning artificial intelligence

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Smith-Purcell radiation from time grating

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Newton 2025年第2期1卷

作者： Juan-Feng Zhu Ayan Nussupbekov Yudi Fan Wenjie Zhou Zicheng Song Xuchen Wang Zi-Wen Zhang Chao-Hai Du Xianlong Wei Ping Bai Ching Eng Png Cheng-Wei Qiu Lin Wu Science Mathematics and Technology Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Singapore Institute of High Performance Computing Agency for Science Technology and Research (A∗STAR) 1 Fusionopolis Way #16-16 Connexis Singapore 138632 Singapore Department of Electrical and Computer Engineering National University of Singapore 4 Engineering Drive 3 Singapore 117583 Singapore Center for Composite Materials and Structures School of Astronautics Harbin Institute of Technology Harbin China Institute of Nanotechnology Karlsruhe Institute of Technology Karlsruhe Germany Optical Communication Systems and Networks School of Electronics Peking University Beijing China Key Laboratory for the Physics and Chemistry of Nanodevices School of Electronics Peking University Beijing China

Smith-Purcell radiation (SPR) arises when an electron moves above a spatial grating, where fixed momentum compensation constrains the emission wavelength. In contrast, temporal SPR ( t -SPR) utilizes a time grating to leverage temporal periodicity for energy compensation, enabling more flexible radiation control. We introduce a generalized dispersion equation for t -SPR that predicts the interplay between radiation frequency, direction, electron velocity, modulation period, and harmonic orders. t -SPR offers several advantages over conventional SPR: robustness ( t -SPR maintains stable emission intensity without rapid decay as the electron moves away from the time grating), versatility ( t -SPR enables precise control via temporal modulation of period, amplitude, and waveform), and amplified emission (temporal modulation introduces additional energy channels, boosting emission). These features make t -SPR highly promising for advanced applications in on-chip light sources and electron accelerators.

关键词： Smith-Purcell radiation time grating photonic time crystal free-electron radiation

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Robust optical-levitation-based metrology of nanoparticle's position and mass

arXiv

引用

arXiv 2020年

作者： Zheng, Yu Zhou, Lei-Ming Dong, Yang Qiu, Cheng-Wei Chen, Xiang-Dong Guo, Guang-Can Sun, Fang-Wen CAS Key Lab of Quantum Information University of Science and Technology of China Hefei230026 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Department of Electrical and Computer Engineering National University of Singapore 4 Engineering Drive 3 Singapore117583 Singapore

Light has shown up an incredibe capability in precision measurement based on opto-mechanic interaction in high vacuum by isolating environment noises. However, there are still obstructions, such as displacement and mass estimation error, highly hampering the improvement of absolute accuracy at the nanoscale. Here, we present a nonlinearity based metrology to precisely measure the position and mass of a nanoparticle with optical levitation under 10−5 mbar, 6-order of magnitude lower than the electrostatic-force and stochastic-force-based counterparts. By precisely controlling the amplitude of the levitated nanoparticle at the nonlinear regime, we realized a feasible subpicometer-level position measurement with an uncertainty of 1.0% without the prior information of mass, which can be further applied to weigh the femtogram-level mass with an uncertainty of 2.2%. It will also pave the way to construct a well-calibrated opto-mechanic platform in high vacuum for high sensitivity and accuracy measurement in force and acceleration at the nanoscale and the study in quantum superposition at the mesoscopic scale. Copyright © 2020, The Authors. All rights reserved.

关键词： Nanoparticles

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Noise can speed Markov chain Monte Carlo estimation and quantum annealing

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Physical Review E 2019年第5期100卷 053309-053309页

作者： Brandon Franzke Bart Kosko Center for Quantum Information Science and Technology Signal and Image Processing Institute Department of Electrical and Computer Engineering University of Southern California Los Angeles California 90089 USA

Carefully injected noise can speed the average convergence of Markov chain Monte Carlo (MCMC) estimates and simulated annealing optimization. This includes quantum annealing and the MCMC special case of the Metropolis-Hastings algorithm. MCMC seeks the solution to a computational problem as the equilibrium probability density of a reversible Markov chain. The algorithm must cycle through a long burn-in phase until it reaches equilibrium because the Markov samples are statistically correlated. The special injected noise reduces this burn-in period in MCMC. A related theorem shows that it reduces the cooling time in simulated annealing. Simulations showed that optimal noise gave a 76% speed-up in finding the global minimum in the Schwefel optimization benchmark. The noise-boosted simulations found the global minimum in 99.8% of trials compared with only 95.4% of trials in noiseless simulated annealing. Simulations also showed that the noise boost is robust to accelerated cooling schedules and that noise decreased convergence times by more than 32% under aggressive geometric cooling. Molecular dynamics simulations showed that optimal noise gave a 42% speed-up in finding the minimum potential energy configuration of an eight-argon-atom gas system with a Lennard-Jones 12-6 potential. The annealing speed-up also extends to quantum Monte Carlo implementations of quantum annealing. Noise improved ground-state energy estimates in a 1024-spin simulated quantum annealing simulation by 25.6%. The quantum noise flips spins along a Trotter ring. The noisy MCMC algorithm brings each Markov step closer on average to equilibrium if an inequality holds between two expectations. Gaussian or Cauchy jump probabilities reduce the noise-benefit inequality to a simple quadratic inequality. Simulations show that noise-boosted simulated annealing is more likely than noiseless annealing to sample high probability regions of the search space and to accept solutions that increase the search bre

关键词： Fluctuations & noise Noise

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Intelligent Backpropagated Neural Networks for Numerical computations for MHD Squeezing Fluid Suspended by Nanoparticles between Two Parallel Plates

Research Square

引用

Research Square 2021年

作者： Shoaib, Muhammad Zahoor Raja, Muhammad Asif Farhat, Imrana Shah, Zahir Kumam, Poom Department of Mathematics COMSATS University Islamabad Attock Campus Pakistan Future Technology Research Center National Yunlin University of Science and Technology 123 University Road Section .3 Douliou Yunlin64002 Taiwan Department of Electrical and Computer Engineering COMSATS University Islamabad Attock Campus Pakistan Department of Mathematics University of Lakki Marwat Lakki Marwat Khyber Pakhtunkhwa 28420 Pakistan 126 Pracha Uthit Rd. Bang Mod Thung Khru Bangkok10140 Thailand 126 Pracha Uthit Rd. Bang Mod Thung Khru Bangkok10140 Thailand

In the present research, artificial intelligence based backpropagated neural networks with Levenberg-Marquardt algorithm (BNN-LMA) are utilized to interpret the numerical computation for squeezing 2D magneto-hydrodynamic (MHD) nanofluid flow between two parallel plates. The non-linear system of ODEs represents the magneto-hydrodynamic, squeezing nanofluidic flow model (MHD-SNFM). A reference dataset for BNN-LMA is formulated by utilizing Adam numerical solver for different scenarios of MHD-SNFM by variation of squeezing number, Hartmann Number and heat source parameter. The validation, testing and training processes of BNN-LMA are exploited to analyze the approximate solution of MHD-SNFM for different scenarios and correctness of proposed BNN-LMA is verified by comparison of reference outcomes. The performance of BNN-LMA to solve the MHD-SNFM is validated through regression analysis, histogram studies and mean square error (MSE). © 2021, CC BY.

关键词： Regression analysis

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Uncertainty-aware Score Distribution Learning for Action Quality Assessment

arXiv

引用

arXiv 2020年

作者： Tang, Yansong Ni, Zanlin Zhou, Jiahuan Zhang, Danyang Lu, Jiwen Wu, Ying Zhou, Jie Department of Automation Tsinghua University China State Key Lab of Intelligent Technologies and Systems China Beijing National Research Center for Information Science and Technology China Tsinghua Shenzhen International Graduate School Tsinghua University China Electrical and Computer Engineering Department Northwestern University

Assessing action quality from videos has attracted growing attention in recent years. Most existing approaches usually tackle this problem based on regression algorithms, which ignore the intrinsic ambiguity in the score labels caused by multiple judges or their subjective appraisals. To address this issue, we propose an uncertainty-aware score distribution learning (USDL) approach for action quality assessment (AQA). Specifically, we regard an action as an instance associated with a score distribution, which describes the probability of different evaluated scores. Moreover, under the circumstance where fine-grained score labels are available (e.g., difficulty degree of an action or multiple scores from different judges), we further devise a multi-path uncertainty-aware score distributions learning (MUSDL) method to explore the disentangled components of a score. We conduct experiments on three AQA datasets containing various Olympic actions and surgical activities, where our approaches set new state-of-the-arts under the Spearman’s Rank Correlation.1 Copyright © 2020, The Authors. All rights reserved.

关键词： Probability distributions

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Stealthy Adversaries against Uncertain Cyber-Physical Systems: Threat of Robust Zero-Dynamics Attack

Stealthy Adversaries against Uncertain Cyber-Physical System...

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作者： Park, Gyunghoon Lee, Chanhwa Shim, Hyungbo Eun, Yongsoon Johansson, Karl H. Center for Intelligent and Interactive Robotics Korea Institute of Science and Technology Seoul136-791 Korea Republic of Research and Development Division Hyundai Motor Company Gyeonggi-do18280 Korea Republic of ASRI Department of Electrical and Computer Engineering Seoul National University Seoul08826 Korea Republic of Department of Information and Communication Engineering Daegu Gyeongbuk Institute of Science and Technology Daegu47988 Korea Republic of ACCESS Linnaeus Centre School of Electrical Engineering KTH Royal Institute of Technology Stockholm144 28 Sweden

In this paper, we address the problem of constructing a robust stealthy attack that compromises uncertain cyber-physical systems having unstable zeros. We first interpret the (non-robust) conventional zero-dynamics attack based on Byrnes-Isidori normal form, and then present a new robust zero-dynamics attack for uncertain plants. Different from the conventional strategy, our key idea is to isolate the real zero-dynamics from the plant's input-output relation and to replace it with an auxiliary nominal zero-dynamics. As a result, this alternative attack does not require the exact model knowledge anymore. The price to pay for the robustness is to utilize the input and output signals of the system (i.e., disclosure resources). It is shown that a disturbance observer can be employed to realize the new attack philosophy when there is a lack of model knowledge. Simulation results with a hydro-turbine power system are presented to verify the attack performance and robustness. © 1963-2012 IEEE.

关键词： Cyber Physical System

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Wide-Field Dynamic Magnetic Microscopy Using Double-Double Quantum Driving of a Diamond Defect Ensemble

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Physical Review Applied 2021年第5期15卷 054032-054032页

作者： Zeeshawn Kazi Isaac M. Shelby Hideyuki Watanabe Kohei M. Itoh Vaithiyalingam Shutthanandan Paul A. Wiggins Kai-Mei C. Fu Physics Department University of Washington Seattle Washington 98105 USA Nanoelectronics Research Institute National Institute of Advanced Industrial Science and Technology Tsukuba Central 2 1-1-1 Umezono Tsukuba Ibaraki 305-8568 Japan Spintronics Research Center Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama 223-8522 Japan School of Fundamental Science and Technology Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama 223-8522 Japan Environmental and Molecular Sciences Laboratory Pacific Northwest National Laboratory Richland Washington 99352 USA Bioengineering Department University of Washington Seattle Washington 98105 USA Electrical and Computer Engineering Department University of Washington Seattle Washington 98105 USA

Wide-field magnetometry can be realized by imaging the optically detected magnetic resonance of diamond nitrogen-vacancy (N-V) center ensembles. However, N-V ensemble inhomogeneities significantly limit the magnetic field sensitivity of these measurements. We demonstrate a double-double quantum (DDQ) driving technique to facilitate wide-field magnetic imaging of dynamic magnetic fields at a micron scale. DDQ imaging employs four-tone radio-frequency pulses to suppress inhomogeneity-induced variations of the N-V resonance response. As a proof of principle, we use the DDQ technique to image the dc magnetic field produced by individual magnetic nanoparticles tethered by single DNA molecules to a diamond-sensor surface. This demonstrates the efficacy of the diamond N-V ensemble system in high-frame-rate magnetic microscopy, as well as single-molecule biophysics applications.

关键词： Quantum control Quantum sensing Radio frequency techniques Magnetic nanoparticles Nitrogen vacancy centers in diamond Solid-state detectors Imaging & optical processing Optically detected magnetic resonance

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Heat capacity of nonequilibrium electron-hole plasma in graphene layers and graphene bilayers

arXiv

引用

arXiv 2020年

作者： Ryzhii, V. Ryzhii, M. Otsuji, T. Mitin, V. Shur, M.S. Research Institute of Electrical Communication Tohoku University Sendai980-8577 Japan Institute of Ultra High Frequency Semiconductor Electronics of RAS Moscow117105 Russia Center for Photonics and Two-Dimensional Materials Moscow Institute of Physics and Technology Dolgoprudny141700 Russia Department of Computer Science and Engineering University of Aizu Aizu-Wakamatsu965-8580 Japan Department of Electrical Engineering University at Buffalo SUNY BuffaloNY1460-1920 United States Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute TroyNY12180 United States

graphene, graphene bilayer, optical carrier heating and cooling, heat capacity We analyze the statistical characteristics of the quasi-nonequilibrium two-dimensional electron-hole plasma in graphene layers (GLs) and graphene bilayers (GBLs) and evaluate their heat capacity. The GL heat capacity of the weakly pumped intrinsic or weakly doped GLs normalized by the Boltzmann constant is equal to cGL 6.58. With varying carrier temperature the intrinsic GBL carrier heat capacity cGBL changes from cGBL 2.37 at T . 300 K to cGBL 6.58 at elevated temperatures. These values are markedly different from the heat capacity of classical two-dimensional carriers with c = 1. The obtained results can be useful for the optimization of different GL- and GBL-based high-speed devices. Copyright © 2020, The Authors. All rights reserved.

关键词： Specific heat

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Robust formation of nanoscale magnetic skyrmions in easy-plane anisotropy thin film multilayers with low damping

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Physical Review B 2021年第10期104卷 L100417-L100417页

作者： Luis Flacke Valentin Ahrens Simon Mendisch Lukas Körber Tobias Böttcher Elisabeth Meidinger Misbah Yaqoob Manuel Müller Lukas Liensberger Attila Kákay Markus Becherer Philipp Pirro Matthias Althammer Stephan Geprägs Hans Huebl Rudolf Gross Mathias Weiler Walther-Meißner Institut Bayerische Akademie der Wissenschaften 85748 Garching Germany Physics Department Technical University of Munich 85748 Garching Germany Department of Electrical and Computer Engineering Technical University of Munich 80333 Munich Germany Helmholtz-Zentrum Dresden - Rossendorf Institute of Ion Beam Physics and Materials Research 01328 Dresden Germany Fakultät Physik Technische Universität Dresden 01062 Dresden Germany Fachbereich Physik and Landesforschungszentrum OPTIMAS Technische Universität Kaiserslautern 67663 Kaiserslautern Germany Munich Center for Quantum Science and Technology (MCQST) 80799 Munich Germany

We experimentally demonstrate the formation of room-temperature skyrmions with radii of about 25 nm in easy-plane anisotropy multilayers with an interfacial Dzyaloshinskii-Moriya interaction (DMI). We detect the formation of individual magnetic skyrmions by magnetic force microscopy and find that the skyrmions are stable in out-of-plane fields up to about 200 mT. We determine the interlayer exchange coupling as well as the strength of the interfacial DMI. Additionally, we investigate the dynamic microwave spin excitations by broadband magnetic resonance spectroscopy. From the uniform Kittel mode we determine the magnetic anisotropy and low damping αG<0.04. We also find clear magnetic resonance signatures in the nonuniform (skyrmion) state. Our findings demonstrate that skyrmions in easy-plane multilayers are promising for spin-dynamical applications.

关键词： Skyrmions Spintronics Chiral magnets Magnetic multilayers Ferromagnetic resonance Magnetic force microscopy Micromagnetic modeling

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