5,541 results match your criteria Algebraic and Geometric Topology[Journal]


Data-Efficient Off-Policy Learning for Distributed Optimal Tracking Control of HMAS With Unidentified Exosystem Dynamics.

IEEE Trans Neural Netw Learn Syst 2022 May 20;PP. Epub 2022 May 20.

In this article, a data-efficient off-policy reinforcement learning (RL) approach is proposed for distributed output tracking control of heterogeneous multiagent systems (HMASs) using approximate dynamic programming (ADP). Different from existing results that the kinematic model of the exosystem is addressable to partial or all agents, the dynamics of the exosystem are assumed to be completely unknown for all agents in this article. To solve this difficulty, an identifiable algorithm using the experience-replay method is designed for each agent to identify the system matrices of the novel reference model instead of the original exosystem. Read More

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Efficiency at optimal performance: A unified perspective based on coupled autonomous thermal machines.

Phys Rev E 2022 Apr;105(4-1):044145

Department of Applied Sciences, University Institute of Engineering and Technology (U.I.E.T), Panjab University, Sector 25, Chandigarh 160014, India.

We show that coupled autonomous thermal machines, in the presence of three heat reservoirs and following a global linear-irreversible description, can have efficiency at maximum power (EMP) which is analogous in form to the EMP of models with two (hot and cold) reservoirs. In particular, the temperature dependence of EMP in the coupled model is via only the ratio of hot and cold temperatures if the intermediate reservoir temperature is expressed as an algebraic mean of these temperatures. Many popular expressions of EMP in the literature can be recovered by making a choice of some standard mean. Read More

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Recurrent neural networks for partially observed dynamical systems.

Phys Rev E 2022 Apr;105(4-1):044205

Applied Mathematics, University of California, Santa Cruz, California 95064, USA.

Complex nonlinear dynamics are ubiquitous in many fields. Moreover, we rarely have access to all of the relevant state variables governing the dynamics. Delay embedding allows us, in principle, to account for unobserved state variables. Read More

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AMR-meta: a k-mer and metafeature approach to classify antimicrobial resistance from high-throughput short-read metagenomics data.

Gigascience 2022 May;11

Department of Computer and Information Science and Engineering, University of Florida, 2004 Mowry Road Gainesville, FL 32610, USA.

Background: Antimicrobial resistance (AMR) is a global health concern. High-throughput metagenomic sequencing of microbial samples enables profiling of AMR genes through comparison with curated AMR databases. However, the performance of current methods is often hampered by database incompleteness and the presence of homology/homoplasy with other non-AMR genes in sequenced samples. Read More

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Sparse Angle CBCT Reconstruction Based on Guided Image Filtering.

Front Oncol 2022 27;12:832037. Epub 2022 Apr 27.

Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), Unité Mixte de Recherche (UMR) 5506, French National Center for Scientific Research (CNRS) - University of Montpellier (UM), Montpellier, France.

Cone-beam Computerized Tomography (CBCT) has the advantages of high ray utilization and detection efficiency, short scan time, high spatial and isotropic resolution. However, the X-rays emitted by CBCT examination are harmful to the human body, so reducing the radiation dose without damaging the reconstruction quality is the key to the reconstruction of CBCT. In this paper, we propose a sparse angle CBCT reconstruction algorithm based on Guided Image FilteringGIF, which combines the classic Simultaneous Algebra Reconstruction Technique(SART) and the Total p-Variation (TpV) minimization. Read More

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Orbital Dynamics in Centrosymmetric Systems.

Phys Rev Lett 2022 Apr;128(17):176601

Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea.

Orbital dynamics in time-reversal-symmetric centrosymmetric systems is examined theoretically. Contrary to common belief, we demonstrate that many aspects of orbital dynamics are qualitatively different from spin dynamics because the algebraic properties of the orbital and spin angular momentum operators are different. This difference generates interesting orbital responses, which do not have spin counterparts. Read More

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Protein-protein interaction network of E. coli K-12 has significant high-dimensional cavities: New insights from algebraic topological studies.

FEBS Open Bio 2022 May 12. Epub 2022 May 12.

Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, 710032, People's Republic of China.

As a model system, Escherichia coli (E. coli) has been used to study various life processes. A dramatic paradigm shift has occurred in recent years, with the study of single proteins moving towards the study of dynamically-interacting proteins, especially protein-protein interaction (PPI) networks. Read More

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Fault Estimation Observer Design for Markovian Jump Systems With Nondifferentiable Actuator and Sensor Failures.

IEEE Trans Cybern 2022 May 13;PP. Epub 2022 May 13.

This article addresses the simultaneous actuator and sensor fault estimation (FE) problem for a class of Markovian jump systems (MJSs) with nondifferentiable actuator failures. In order to overcome the difficulties brought by the nondifferentiable actuator failures, we construct an extended vector composed of states, sensor faults, and disturbances, where the derivatives of actuator failures are not required in this augmented system. Then, two novel observer-based approaches are developed for the augmented descriptor system to cope with the FE problem. Read More

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A Parameter Representing Missing Charge Should Be Considered when Calibrating Action Potential Models.

Front Physiol 2022 26;13:879035. Epub 2022 Apr 26.

Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom.

Computational models of the electrical potential across a cell membrane are longstanding and vital tools in electrophysiology research and applications. These models describe how ionic currents, internal fluxes, and buffering interact to determine membrane voltage and form action potentials (APs). Although this relationship is usually expressed as a differential equation, previous studies have shown it can be rewritten in an algebraic form, allowing direct calculation of membrane voltage. Read More

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PARTITIONING SIGNAL CLASSES USING TRANSPORT TRANSFORMS FOR DATA ANALYSIS AND MACHINE LEARNING.

Sampl Theory Signal Process Data Anal 2021 Jun 11;19(1). Epub 2021 May 11.

Imaging and Data Science Laboratory Department of Biomedical Engineering Department of Electrical and Computer Engineering University of Virginia.

A relatively new set of transport-based transforms (CDT, R-CDT, LOT) have shown their strength and great potential in various image and data processing tasks such as parametric signal estimation, classification, cancer detection among many others. It is hence worthwhile to elucidate some of the mathematical properties that explain the successes of these transforms when they are used as tools in data analysis, signal processing or data classification. In particular, we give conditions under which classes of signals that are created by algebraic generative models are transformed into convex sets by the transport transforms. Read More

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Fast parallel implementation for total variation constrained algebraic reconstruction technique.

J Xray Sci Technol 2022 May 2. Epub 2022 May 2.

In computed tomography (CT), the total variation (TV) constrained algebraic reconstruction technique (ART) can obtain better reconstruction quality when the projection data are sparse and noisy. However, the ART-TV algorithm remains time-consuming since it requires large numbers of iterations, especially for the reconstruction of high-resolution images. In this work, we propose a fast algorithm to calculate the system matrix for line intersection model and apply this algorithm to perform the forward-projection and back-projection operations of the ART. Read More

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Prosthesis-Implant Arch Area Ratio (PIAAR) - A New Geometric Paradigm, Replacing the Current 'A-P Spread' of a Cantilever in Full-Arch Implant Prosthesis: A Proof-of-Concept Experiment.

Authors:
Young K Kim

J Prosthodont 2022 May 5. Epub 2022 May 5.

Department of Prosthodontics, NYU College of Dentistry, New York, NY.

Purpose: The anterior-posterior spread concept is relied upon to understand the bioengineering aspects of cantilevers in fixed complete denture prostheses. This concept is not evidence-based. With no other category existing in contemporary implant dentistry, this conventional anterior-posterior spread concept may have limited more precise and accurate biomechanical analysis. Read More

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A new algebraic approach to genome rearrangement models.

J Math Biol 2022 May 5;84(6):49. Epub 2022 May 5.

Discipline of Mathematics, School of Natural Sciences, University of Tasmania, Private Bag 37, Sandy Bay, TAS, 7001, Australia.

We present a unified framework for modelling genomes and their rearrangements in a genome algebra, as elements that simultaneously incorporate all physical symmetries. Building on previous work utilising the group algebra of the symmetric group, we explicitly construct the genome algebra for the case of unsigned circular genomes with dihedral symmetry and show that the maximum likelihood estimate (MLE) of genome rearrangement distance can be validly and more efficiently performed in this setting. We then construct the genome algebra for a more general case, that is, for genomes that may be represented by elements of an arbitrary group and symmetry group, and show that the MLE computations can be performed entirely within this framework. Read More

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Topological data analysis in biomedicine: A review.

J Biomed Inform 2022 May 1;130:104082. Epub 2022 May 1.

University of Florida, Department of Mathematics, Gainesville, FL, USA; University of Florida, Department of Medicine, Division of Pulmonary, Critical Care, & Sleep Medicine, Gainesville, FL, USA. Electronic address:

Significant technological advances made in recent years have shepherded a dramatic increase in utilization of digital technologies for biomedicine- everything from the widespread use of electronic health records to improved medical imaging capabilities and the rising ubiquity of genomic sequencing contribute to a "digitization" of biomedical research and clinical care. With this shift toward computerized tools comes a dramatic increase in the amount of available data, and current tools for data analysis capable of extracting meaningful knowledge from this wealth of information have yet to catch up. This article seeks to provide an overview of emerging mathematical methods with the potential to improve the abilities of clinicians and researchers to analyze biomedical data, but may be hindered from doing so by a lack of conceptual accessibility and awareness in the life sciences research community. Read More

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Fault Diagnosis in Regenerative Braking System of Hybrid Electric Vehicles by Using Semigroup of Finite-State Deterministic Fully Intuitionistic Fuzzy Automata.

Comput Intell Neurosci 2022 22;2022:3684727. Epub 2022 Apr 22.

Department of Mathematics, University of Gondar, P.O. Box: 196, Gondar, Ethiopia.

Regenerative braking is one of the most promising and ecologically friendly solutions for improving energy efficiency and vehicle stability in electric and hybrid electric cars. This research describes a data-driven method for detecting and diagnosing issues in hybrid electric vehicle regenerative braking systems. Early fault identification can help enhance system performance and health. Read More

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Optimization of AES-128 Encryption Algorithm for Security Layer in ZigBee Networking of Internet of Things.

Comput Intell Neurosci 2022 19;2022:8424100. Epub 2022 Apr 19.

School of Electronics and Information, Nanchang Institute of Technology, Nanchang 330044, Jiangxi, China.

With the rapid development of network and communication technology, the interaction of various information data is more and more frequent, and people pay more and more attention to information security. The information encryption algorithm is a research hotspot in the field of information security. The Advanced Encryption Standard (AES) algorithm has been widely used in the field of information security with its high security and encryption efficiency. Read More

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Online Strategies To Improve Quantitative Skills in Microbiology Laboratory Classes.

J Microbiol Biol Educ 2022 Apr 28;23(1). Epub 2022 Mar 28.

Department of Biology, Virginia Commonwealth University, Richmond, Virginia, USA.

Biology is an increasingly quantitative science. Thus, it is important that undergraduate biology curricula include frequent opportunities for students to practice their quantitative skills. This can create a substantial grading burden for faculty teaching online and/or large enrollment courses, but the "formula question" feature present in many learning management systems (LMS) offers a solution. Read More

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SHIFTING POWERS IN SPIVEY'S BELL NUMBER FORMULA.

Quaest Math 2022 5;45(1):55-69. Epub 2020 Dec 5.

Department of Mathematics, University of Tennessee, 37996 Knoxville, TN.

In this paper, we consider extensions of Spivey's Bell number formula wherein the argument of the polynomial factor is translated by an arbitrary amount. This idea is applied more generally to the -Whitney numbers of the second kind, denoted by (), where some new identities are found by means of algebraic and combinatorial arguments. The former makes use of infinite series manipulations and Dobinski-like formulas satisfied by (), whereas the latter considers distributions of certain statistics on the underlying enumerated class of set partitions. Read More

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December 2020

Separability of stereoisomers by electrokinetic chromatography in presence of a neutral selector - Fundamental aspects assessed by computer simulation.

J Chromatogr A 2022 Apr 22;1673:463087. Epub 2022 Apr 22.

Institute for Infectious Diseases, University of Bern, Bern, Switzerland. Electronic address:

The impact of the two essential parameters, the complexation constant and the mobility of the formed diastereomeric complex, on stereoisomer separation in presence of a neutral chiral selector was assessed by computer simulation for an electrokinetic chromatography configuration with a uniform background electrolyte and one with a cationic discontinues buffer system of isotachophoretic nature. With two enantiomers of norpseudoephedrine as model analytes, data for seven cases featuring complexation in free solution with various combinations of input values, complexation with an immobilized selector and no complexation were analyzed in a hitherto unexplored way. For the uniform buffer study, the determined differences of the effective mobilities and separation selectivities of the stereoisomers were found to be equal to those calculated with the well-known algebraic equations. Read More

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Using core-hole reference states for calculating X-ray photoelectron and emission spectra.

Phys Chem Chem Phys 2022 May 11;24(18):11259-11267. Epub 2022 May 11.

Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm 10691, Sweden.

For the calculation of core-ionization energies (IEs), X-ray photoelectron spectra (XPS), and X-ray emission spectra (XES), a commonly applied approach is to use non- reference states with a core-hole as either final (IE and XPS) or initial (XES) state. However, such reference states can introduce numerical instabilities in post-HF methods, relating to the denominator of the energy corrections involved. This may become arbitrarily close to zero if a negative virtual orbital is present, a core-hole, leading to near-singularities. Read More

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A State Space Approach to Decentralized Fault SE-Coprognosability of Partially Observed Discrete Event Systems.

IEEE Trans Cybern 2022 Apr 27;PP. Epub 2022 Apr 27.

The problem of fault prognosis in the context of discrete event systems (DESs) is a crucial subject to study the security and maintenance of cyber-physical systems. In this article, the decentralized fault prognosis of partially observed DESs is analyzed with a universal state-estimate-based protocol. It follows (M,K) as the performance bound of any expected decentralized prognosers, where any fault can be predicted K steps before its occurrence and the fault is guaranteed to occur within M steps once a corresponding fault alarm is issued. Read More

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Mathematical artificial intelligence design of mutation-proof COVID-19 monoclonal antibodies.

ArXiv 2022 Apr 20. Epub 2022 Apr 20.

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have compromised existing vaccines and posed a grand challenge to coronavirus disease 2019 (COVID-19) prevention, control, and global economic recovery. For COVID-19 patients, one of the most effective COVID-19 medications is monoclonal antibody (mAb) therapies. The United States Food and Drug Administration (U. Read More

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Inverse design assisted coherent optical lattices.

Opt Express 2022 Mar;30(7):11384-11393

We explore the use of inverse design methods for the generation of periodic optical patterns in photonic integrated circuits. A carefully selected objective function based on the integer lattice method, which is an algebraic technique for optical lattice generation, is shown to be key for successful device design. Furthermore, we present a polychromatic pattern generating device that switches between optical lattices with different symmetry and periodicity depending on the operating wavelength. Read More

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Damping of relaxation oscillations, photon-photon resonance, and tolerance to external optical feedback of III-V/SiN hybrid lasers with a dispersive narrow band mirror.

Opt Express 2022 Mar;30(7):11090-11109

We address the stability of a tunable hybrid laser based on a III-V Reflective Semiconductor Optical Amplifier (RSOA) edge-coupled with a Silicon Photonic (SiPh) dispersive mirror through a model of time-delayed algebraic differential equations that accounts for the narrow band mirror. Our results allow to (i) analyze the stability of single mode lasing, (ii) quantify the impact of the mirror bandwidth on the damping of the laser relaxation oscillations and the emergence of photon-photon resonance, and (iii) study the tolerance of the laser to the external optical feedback. Thanks to this analysis, we find a mirror design that gives ultra-high stability up to an external feedback level of -10 dB. Read More

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Impact of e-money on money supply: Estimation and policy implication for Bangladesh.

PLoS One 2022 26;17(4):e0267595. Epub 2022 Apr 26.

The Central Bank of Bangladesh, Motijheel, Dhaka, Bangladesh.

With the rapid proliferation of mobile telephony and the establishment of an IT-enabled payment and settlement system, Bangladesh nowadays is experiencing a remarkable growth in the usage of mobile financial services (MFS). As more and more people are opting to use this service, a huge number of mobile accounts are opened every day and a substantial amount of money is deposited, withdrawn and transferred frequently through the mobile network. This ever-increasing amount of mobile money flowing through the network may have a sizeable impact on the overall money supply of the country. Read More

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Analysis and data-based modeling of the photochemical reaction dynamics of the induced singlet oxygen in light therapies.

IEEE Trans Biomed Eng 2022 Apr 26;PP. Epub 2022 Apr 26.

Objective: The macroscopic singlet oxygen (MSO) model for quantifying the light-induced singlet oxygen (1O2) always contain a set of nonlinear dynamic equations and therefore are generally difficult to be applied. This work was devoted to analyze and simplify this dynamic model.

Methods: Firstly, the nonlinearity of the MSO model was analyzed. Read More

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Omicron BA.2 (B.1.1.529.2): High Potential for Becoming the Next Dominant Variant.

J Phys Chem Lett 2022 May 25;13(17):3840-3849. Epub 2022 Apr 25.

Department of Mathematics, Michigan State University, East Lansing, Michigan 48824, United States.

The Omicron variant has three subvariants: BA.1 (B.1. Read More

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Origin invariant electronic circular dichroism in the length dipole gauge without London atomic orbitals.

J Chem Phys 2022 Apr;156(15):154114

Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.

We present a method for obtaining origin-independent electronic circular dichroism (ECD) in the length-gauge representation LG(OI) without the usage of London atomic orbitals. This approach builds upon the work by Caricato [J. Chem. Read More

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New Bounds and a Generalization for Share Conversion for 3-Server PIR.

Entropy (Basel) 2022 Apr 1;24(4). Epub 2022 Apr 1.

Computer Science Department, Ariel University, Ariel 40700, Israel.

Private Information Retrieval (PIR) protocols, which allow the client to obtain data from servers without revealing its request, have many applications such as anonymous communication, media streaming, blockchain security, advertisement, etc. Multi-server PIR protocols, where the database is replicated among the non-colluding servers, provide high efficiency in the information-theoretic setting. Beimel et al. Read More

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Dynamic Analysis and Optimal Control of Rumor Spreading Model with Recurrence and Individual Behaviors in Heterogeneous Networks.

Entropy (Basel) 2022 Mar 27;24(4). Epub 2022 Mar 27.

College of Mathematics and System Science, Xinjiang University, Urumqi 830046, China.

This paper is devoted to investigating the impact of the recurrence of rumors and individual behaviors and control strategies related to rumor spreading in online social networks. To do this, a novel susceptible-hesitating-infected-latent-recovered (SHILR) rumor propagation model in heterogeneous networks is presented. Firstly, based on the relevant mean-field equations of the model, the threshold value is examined to demonstrate the existence and stability of rumor-free/spreading equilibrium with the help of the algebraic method. Read More

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