4,543 results match your criteria Algebraic And Geometric Topology[Journal]


Fast and accurate tumor segmentation of histology images using persistent homology and deep convolutional features.

Med Image Anal 2019 Apr 4;55:1-14. Epub 2019 Apr 4.

Department of Computer Science, University of Warwick, UK; Department of Pathology, University Hospitals Coventry and Warwickshire, UK; The Alan Turing Institute, UK. Electronic address:

Tumor segmentation in whole-slide images of histology slides is an important step towards computer-assisted diagnosis. In this work, we propose a tumor segmentation framework based on the novel concept of persistent homology profiles (PHPs). For a given image patch, the homology profiles are derived by efficient computation of persistent homology, which is an algebraic tool from homology theory. Read More

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http://dx.doi.org/10.1016/j.media.2019.03.014DOI Listing

Boolean network analysis through the joint use of linear algebra and algebraic geometry.

J Theor Biol 2019 Apr 15;472:46-53. Epub 2019 Apr 15.

Dipartimento di Ingegneria Civile e Ingegneria Informatica, Università di Roma Tor Vergata, Roma 00133, Italy. Electronic address:

Among the various phenomena that can be modeled by Boolean networks, i.e., discrete-time dynamical systems with binary state variables, gene regulatory interactions are especially well known. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S00225193193015
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http://dx.doi.org/10.1016/j.jtbi.2019.04.012DOI Listing
April 2019
1 Read

Local Synchronization of Interconnected Boolean Networks With Stochastic Disturbances.

IEEE Trans Neural Netw Learn Syst 2019 Apr 11. Epub 2019 Apr 11.

This paper is concerned with the local synchronization problem for the interconnected Boolean networks (BNs) without and with stochastic disturbances. For the case without stochastic disturbances, first, the limit set and the transient period of the interconnected BNs are discussed by resorting to the properties of the reachable set for the global initial states set. Second, in terms of logical submatrices of a certain Boolean vector, a compact algebraic expression is presented for the limit set of the given initial states set. Read More

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http://dx.doi.org/10.1109/TNNLS.2019.2904978DOI Listing

Adaptive Optimal Control for a Class of Nonlinear Systems: The Online Policy Iteration Approach.

IEEE Trans Neural Netw Learn Syst 2019 Apr 11. Epub 2019 Apr 11.

This paper studies the online adaptive optimal controller design for a class of nonlinear systems through a novel policy iteration (PI) algorithm. By using the technique of neural network linear differential inclusion (LDI) to linearize the nonlinear terms in each iteration, the optimal law for controller design can be solved through the relevant algebraic Riccati equation (ARE) without using the system internal parameters. Based on PI approach, the adaptive optimal control algorithm is developed with the online linearization and the two-step iteration, i. Read More

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http://dx.doi.org/10.1109/TNNLS.2019.2905715DOI Listing
April 2019
1 Read

Evaluation of The Final Time and Velocity of a 100 m Run Under the Realistic Conditions.

J Hum Kinet 2019 Mar 27;66:19-29. Epub 2019 Mar 27.

University of Novi Sad, Department of Physics, Faculty of Sciences, Novi Sad, Serbia.

The aim of the research was to provide an analytical expression for the final time and velocity at the 100 m run, taking into account realistic conditions of the run, more precisely the effect of the wind and resistance of the medium (air). Combining the polynomial model for the distance vs time with the solution of the algebraic cubic equation, such an analytical expression was derived. The expression allowed to evaluate the dependence of the final time of the race on the wind velocity. Read More

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http://content.sciendo.com/view/journals/hukin/66/1/article-
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http://dx.doi.org/10.2478/hukin-2018-0048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6458572PMC
March 2019
2 Reads

Podokinetic After-Rotation Is Transiently Enhanced or Reversed by Unilateral Axial Muscle Proprioceptive Stimulation.

Neural Plast 2019 11;2019:7129279. Epub 2019 Mar 11.

LUNEX International University of Health, Exercise and Sports, Differdange, Luxembourg.

Unilateral axial muscle vibration, eliciting a proprioceptive volley, is known to incite steering behavior. Whole-body rotation while stepping in place also occurs as an after-effect of stepping on a circular treadmill (podokinetic after-rotation, PKAR). Here, we tested the hypothesis that PKAR is modulated by axial muscle vibration. Read More

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http://dx.doi.org/10.1155/2019/7129279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6432728PMC

Bootstrapping variables in algebraic circuits.

Proc Natl Acad Sci U S A 2019 Apr 11. Epub 2019 Apr 11.

Department of Computer Science & Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India

We show that for the blackbox polynomial identity testing (PIT) problem it suffices to study circuits that depend only on the first extremely few variables. One needs only to consider size-s degree-s circuits that depend on the first [Formula: see text] variables (where c is a constant and composes a logarithm with itself c times). Thus, the hitting-set generator (hsg) manifests a bootstrapping behavior-a partial hsg against very few variables can be efficiently grown to a complete hsg. Read More

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http://dx.doi.org/10.1073/pnas.1901272116DOI Listing

Numerical analysis of an enhanced cooling rate cryopreservation process in a biological tissue.

Authors:
S Sukumar S P Kar

J Therm Biol 2019 Apr 5;81:146-153. Epub 2019 Mar 5.

School of Mechanical Engineering, KIIT Deemed To Be University, Bhubaneswar, Odisha 751024, India. Electronic address:

Cryopreservation is the method of preservation of biological tissues for future references without causing significant damages to their physical and functional properties. This can be done by exposing them to very low cryogenic temperature that involves a greater heat removal rate. A two dimensional numerical model is developed to study the temperature distribution, cooling rate attained and movement of the freezing front during the cryopreservation process. Read More

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http://dx.doi.org/10.1016/j.jtherbio.2019.03.001DOI Listing

A physically based model for mesoscale SuDS - an alternative to large-scale urban drainage simulations.

J Environ Manage 2019 Apr 5. Epub 2019 Apr 5.

Department of Water Resources Engineering, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden. Electronic address:

This study presents a deterministic, lumped model to simulate mesoscale sustainable drainage systems (SuDS) based on a conceptualization of the stormwater control measures (SCMs) making up the system and their influence on the runoff process. The conceptualization mainly relies on parameters that are easily quantifiable based on the physical characteristics of the SCMs. Introducing a nonlinear reservoir model at the downstream end of the SuDS results in a fast model that can realistically describe the runoff process at low computational cost. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S03014797193033
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http://dx.doi.org/10.1016/j.jenvman.2019.03.037DOI Listing
April 2019
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Tensor clustering with algebraic constraints gives interpretable groups of crosstalk mechanisms in breast cancer.

J R Soc Interface 2019 Feb;16(151):20180661

2 Mathematical Institute, University of Oxford , Oxford OX2 6GG , UK.

We introduce a tensor-based clustering method to extract sparse, low-dimensional structure from high-dimensional, multi-indexed datasets. This framework is designed to enable detection of clusters of data in the presence of structural requirements which we encode as algebraic constraints in a linear program. Our clustering method is general and can be tailored to a variety of applications in science and industry. Read More

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http://dx.doi.org/10.1098/rsif.2018.0661DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408352PMC
February 2019

Analysing diffusion and flow-driven instability using semidefinite programming.

J R Soc Interface 2019 Jan;16(150):20180586

2 Department of Information Physics and Computing, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 , Japan.

Diffusion and flow-driven instability, or transport-driven instability, is one of the central mechanisms to generate inhomogeneous gradient of concentrations in spatially distributed chemical systems. However, verifying the transport-driven instability of reaction-diffusion-advection systems requires checking the Jacobian eigenvalues of infinitely many Fourier modes, which is computationally intractable. To overcome this limitation, this paper proposes mathematical optimization algorithms that determine the stability/instability of reaction-diffusion-advection systems by finite steps of algebraic calculations. Read More

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http://dx.doi.org/10.1098/rsif.2018.0586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6364638PMC
January 2019

A novel, FFT-based one-dimensional blood flow solution method for arterial network.

Biomech Model Mechanobiol 2019 Apr 6. Epub 2019 Apr 6.

Biomedical Engineering Group, Zienkiweicz Centre for Computational Engineering, College of Engineering, Swansea University, Bay Campus, Fabian Road, Swansea, SA2 8PP, UK.

In the present work, we propose an FFT-based method for solving blood flow equations in an arterial network with variable properties and geometrical changes. An essential advantage of this approach is in correctly accounting for the vessel skin friction through the use of Womersley solution. To incorporate nonlinear effects, a novel approximation method is proposed to enable calculation of nonlinear corrections. Read More

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http://dx.doi.org/10.1007/s10237-019-01146-0DOI Listing
April 2019
1 Read

Cluster perturbation theory. IV. Convergence of cluster perturbation series for energies and molecular properties.

J Chem Phys 2019 Apr;150(13):134111

Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.

The theoretical foundation has been developed for establishing whether cluster perturbation (CP) series for the energy, molecular properties, and excitation energies are convergent or divergent and for using a two-state model to describe the convergence rate and convergence patterns of the higher-order terms in the CP series. To establish whether the perturbation series are convergent or divergent, a fictitious system is introduced, for which the perturbation is multiplied by a complex scaling parameter z. The requirement for convergent perturbation series becomes that the energy or molecular property, including an excitation energy, for the fictitious system is an analytic, algebraic function of z that has no singularities when the norm |z| is smaller than one. Read More

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http://dx.doi.org/10.1063/1.5053622DOI Listing
April 2019
3 Reads

Bifurcation manifolds in predator-prey models computed by Gröbner basis method.

Math Biosci 2019 Apr 1;312:1-7. Epub 2019 Apr 1.

Department of Mathematics and Statistics, Section of Applied Mathematics, Faculty of Science, Masaryk University, Kotlářská 2, Brno, 611 37, Czechia.

Many natural processes studied in population biology, systems biology, biochemistry, chemistry or physics are modeled by dynamical systems with polynomial or rational right-hand sides in state and parameter variables. The problem of finding bifurcation manifolds of such discrete or continuous dynamical systems leads to a problem of finding solutions to a system of non-linear algebraic equations. This approach often fails since it is not possible to express equilibria explicitly. Read More

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http://dx.doi.org/10.1016/j.mbs.2019.03.008DOI Listing

Allele fixation probability in a Moran model with fluctuating fitness landscapes.

Phys Rev E 2019 Feb;99(2-1):022407

National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.

Evolution on changing fitness landscapes (seascapes) is an important problem in evolutionary biology. We consider the Moran model of finite population evolution with selection in a randomly changing, dynamic environment. In the model, each individual has one of the two alleles, wild type or mutant. Read More

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https://link.aps.org/doi/10.1103/PhysRevE.99.022407
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http://dx.doi.org/10.1103/PhysRevE.99.022407DOI Listing
February 2019
2 Reads

Variational schemes and geometric simulations for a hydrodynamic-electrodynamic model of surface plasmon polaritons.

Phys Rev E 2019 Feb;99(2-1):023313

State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System, Luoyang, Henan 471000, China.

A class of variational schemes for the hydrodynamic-electrodynamic model of lossless free-electron gas in a quasineutral background is developed for high-quality simulations of surface plasmon polaritons. The Lagrangian density of lossless free-electron gas with a self-consistent electromagnetic field is established, and the dynamical equations with the associated constraints are obtained via a variational principle. Based on discrete exterior calculus, the action functional of this system is discretized and minimized to obtain the discrete dynamics. Read More

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http://dx.doi.org/10.1103/PhysRevE.99.023313DOI Listing
February 2019

High-level theoretical benchmark investigations of the UV-vis absorption spectra of paradigmatic polycyclic aromatic hydrocarbons as models for graphene quantum dots.

J Chem Phys 2019 Mar;150(12):124302

School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, People's Republic of China.

Five paradigmatic polycyclic aromatic hydrocarbons (PAHs) (pyrene, circum-1-pyrene, coronene, circum-1-coronene, and circum-2-coronene) are used for studying the performance of three single-reference methods {scaled opposite-spin-algebraic diagrammatic construction to second-order [SOS-ADC(2)], time-dependent (TD)-B3LYP, and TD-Coulomb-attenuating method (CAM)-B3LYP} and three multireference (MR) methods [density functional theory/multireference configuration interaction (DFT/MRCI), strongly contracted-n-electron valence state perturbation theory to second order (NEVPT2), and spectroscopy oriented configuration interaction (SORCI)]. The performance of these methods was evaluated by comparison of the calculated vertical excitation energies with experiments, where available. DFT/MRCI performs best and thus was used as a benchmark for other approaches where experimental values were not available. Read More

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http://dx.doi.org/10.1063/1.5086760DOI Listing
March 2019
3 Reads

A more accurate method to interpret lactate dehydrogenase (LDH) isoenzymes' results in patients with uterine masses.

Eur J Obstet Gynecol Reprod Biol 2019 Mar 19;236:143-147. Epub 2019 Mar 19.

Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, University of Naples "Federico II", Naples, Italy.

Objective: Since there are no approved reliable biomarkers for detecting preoperatively uterine sarcoma, lactate dehydrogenase (LDH) isoenzymes are usually required. We first evaluated the role of LDH isoenzymes in detecting uterine sarcoma risk, and then we tried to introduce a model to easily interpret the biochemical results.

Methods: We retrospectively retrieved records of patients who underwent surgical treatment for uterine masses from 2004 to 2016, and we compared data of 2211 patients with a definitive surgical diagnosis of uterine fibroids and 43 with uterine sarcomas. Read More

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http://dx.doi.org/10.1016/j.ejogrb.2019.03.017DOI Listing

An exact solution for unit elasticity in the exponential model of operant demand.

Exp Clin Psychopharmacol 2019 Mar 28. Epub 2019 Mar 28.

Institutes for Behavior Resources.

Research applying the behavioral economic demand framework is increasingly conducted across disciplines. With respect to psychopharmacology and substance abuse, real and hypothetical purchase tasks are regularly used to evaluate the demand for various substances and reinforcers, such as alcohol. At present, a variety of methods has been introduced to solve for the point of unit elasticity, or Pmax, in the exponential model of demand; however, these methods vary in their potential for error. Read More

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http://dx.doi.org/10.1037/pha0000268DOI Listing

Mechanical property of the helical configuration for a twisted intrinsically straight biopolymer.

Eur Biophys J 2019 Mar 27. Epub 2019 Mar 27.

Department of Physics and ITPA, Xiamen University, Xiamen, 361005, Fujian, China.

We explore the effects of two typical torques on the mechanical property of the helical configuration for an intrinsically straight filament or biopolymer either in three-dimensional space or on a cylinder. One torque is parallel to the direction of a uniaxial applied force, and is coupled to the cross section of the filament. We obtain some algebraic equations for the helical configuration and find that the boundary conditions are crucial. Read More

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http://dx.doi.org/10.1007/s00249-019-01357-4DOI Listing

On Construction of Projection Operators.

Authors:
Artur F Izmaylov

J Phys Chem A 2019 Apr 8;123(15):3429-3433. Epub 2019 Apr 8.

Department of Physical and Environmental Sciences , University of Toronto Scarborough , Toronto , Ontario M1C 1A4 , Canada.

The problem of construction of projection operators on eigensubspaces of symmetry operators is considered. This problem arises in many approximate methods for solving time-independent and time-dependent quantum problems, and its solution ensures proper physical symmetries in development of approximate methods. The projector form is sought as a function of symmetry operators and their eigenvalues characterizing the eigensubspace of interest. Read More

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http://dx.doi.org/10.1021/acs.jpca.9b01103DOI Listing

Investigation of transmission computed tomography (CT) image quality and x-ray dose achievable from an experimental dual-mode benchtop x-ray fluorescence CT and transmission CT system.

J Xray Sci Technol 2019 Mar 21. Epub 2019 Mar 21.

Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

Objective: To investigate the image quality and x-ray dose associated with a transmission computed tomography (CT) component implemented within the same platform of an experimental benchtop x-ray fluorescence CT (XFCT) system for multimodal preclinical imaging applications.

Methods: Cone-beam CT scans were performed using an experimental benchtop CT + XFCT system and a cylindrically-shaped 3D-printed polymethyl methacrylate phantom (3 cm in diameter, 7 cm in height) loaded with various concentrations (0.05-1 wt. Read More

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http://dx.doi.org/10.3233/XST-180457DOI Listing

Scalable nonlinear programming framework for parameter estimation in dynamic biological system models.

PLoS Comput Biol 2019 Mar 25;15(3):e1006828. Epub 2019 Mar 25.

Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.

We present a nonlinear programming (NLP) framework for the scalable solution of parameter estimation problems that arise in dynamic modeling of biological systems. Such problems are computationally challenging because they often involve highly nonlinear and stiff differential equations as well as many experimental data sets and parameters. The proposed framework uses cutting-edge modeling and solution tools which are computationally efficient, robust, and easy-to-use. Read More

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http://dx.doi.org/10.1371/journal.pcbi.1006828DOI Listing

HUMAN-INSPIRED ALGEBRAIC CURVES FOR WEARABLE ROBOT CONTROL.

Proc ASME Dyn Syst Control Conf 2018 Sep;2018

Dept. Bioengineering and Dept. Mechanical Engineering, The University of Texas at Dallas, Richardson, Texas 75080,

Having unified representations of human walking gait data is of paramount importance for wearable robot control. In the rehabilitation robotics literature, control approaches that unify the gait cycle of wearable robots are more appealing than the conventional approaches that rely on dividing the gait cycle into several periods, each with their own distinct controllers. In this article we propose employing algebraic curves to represent human walking data for wearable robot controller design. Read More

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http://dx.doi.org/10.1115/DSCC2018-9061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6424523PMC
September 2018

Spatial-Spectral Cube Matching Frame for Spectral CT Reconstruction.

Inverse Probl 2018 Oct 14;34(10). Epub 2018 Aug 14.

Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USA.

Spectral computed tomography (CT) reconstructs the same scanned object from projections of multiple narrow energy windows, and it can be used for material identification and decomposition. However, the multi-energy projection dataset has a lower signal-noise-ratio (SNR), resulting in poor reconstructed image quality. To address this thorny problem, we develop a spectral CT reconstruction method, namely spatial-spectral cube matching frame (SSCMF). Read More

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http://dx.doi.org/10.1088/1361-6420/aad67bDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6424516PMC
October 2018

Iterative Solvers for Empirical Partial Atomic Charges: Breaking the Curse of Cubic Numerical Complexity.

J Chem Inf Model 2019 Apr 3. Epub 2019 Apr 3.

Department of Chemistry , Lomonosov Moscow State University , Moscow 119991 , Russian Federation.

Rational drug design involves a vast amount of computations to get thermodynamically reliable results and often relies on atomic charges as a means to model electrostatic interactions within the system. Computational inefficiency often hampers the development of new and wider dissemination of the known methods; thus, any source to speed up the calculations without a sacrifice in quality is warranted. At the heart of many empirical methods of calculating atomic charges is the solution of a system of linear algebraic equations (SLAE). Read More

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http://dx.doi.org/10.1021/acs.jcim.8b00848DOI Listing

Takagi-Sugeno fuzzy model based shaft torque estimation for integrated motor-transmission system.

Authors:
Xiaoyuan Zhu Wei Li

ISA Trans 2019 Mar 11. Epub 2019 Mar 11.

School of Logistics Engineering, Shanghai Maritime University, Shanghai 201306, China. Electronic address:

Shaft torque information is of great importance to develop advanced control system for electrified powertrains. However, it is rarely practical to find durable and also affordable physical sensors to achieve accurate torque measurement in commercial vehicles. This paper investigates a model based shaft torque estimation approach for integrated motor-transmission (IMT) system. Read More

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http://dx.doi.org/10.1016/j.isatra.2019.03.002DOI Listing
March 2019
2 Reads
2.256 Impact Factor

Ultrasound shear wave simulation of wave propagation at oblique angles.

Australas Phys Eng Sci Med 2019 Mar 15. Epub 2019 Mar 15.

Department of Electronic Engineering and Interdisciplinary Graduate Program for BIT Medical Convergence, Kangwon National University, Chuncheon-si, Republic of Korea.

Shear wave elasticity imaging (SWEI) has been used to measure the local tissue elasticity. The local tissue shear modulus can be reconstructed from the displacement field of shear waves using an algebraic Helmholtz inversion (AHI) equation or a time-of-flight (TOF)-based algorithm. The shear waves, which are generated by successive focusing of ultrasonic beams at different depths, propagate at oblique angles rather than along the lateral position. Read More

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http://dx.doi.org/10.1007/s13246-019-00748-3DOI Listing

Absorption shifts of diastereotopically ligated chlorophyll dimers of photosystem I.

Phys Chem Chem Phys 2019 Mar;21(13):6851-6858

Department of Computer Science, Stanford University, 353 Serra Mall, Stanford, CA-94305, USA.

The light-harvesting chlorophyll (Chl) molecules of photosynthetic systems form the basis for light-driven energy conversion. In biological environments, the Chl chromophores occur in two distinct diastereotopic configurations, where the α and β configurations have a magnesium-ligating histidine residue and a 17-propionic acid moiety on the opposite side or on the same side of the Chl ring, respectively. Although β-ligated Chl dimers occupy conserved positions around the reaction center of photosystem I (PSI), the functional relevance of the α/β configuration of the ligation is poorly understood. Read More

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http://dx.doi.org/10.1039/c9cp00616hDOI Listing
March 2019
1 Read

Complete Mueller matrix from a partial polarimetry experiment: the 12-element case.

J Opt Soc Am A Opt Image Sci Vis 2019 Mar;36(3):416-427

Conventional generalized ellipsometry instrumentation is capable of measuring 12 out of the 16 elements of the Mueller matrix of the sample. The missing column (or row) of the experimental partial Mueller matrix can be analytically determined under additional assumptions. We identify the conditions necessary for completing the partial Mueller matrix to a full one. Read More

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http://dx.doi.org/10.1364/JOSAA.36.000416DOI Listing

Numerical and experimental validation of a single-camera 3D velocimetry based on endoscopic tomography.

Appl Opt 2019 Feb;58(6):1363-1373

Tomographic velocimetry as a 3D technique has attracted substantial research interests in recent years due to the pressing need for investigations of complex turbulent flows, which are inherently inhomogeneous. However, tomographic velocimetry usually suffers from high experimental costs, especially due to the formidable expenses of multiple high-speed cameras and the excitation laser source. To overcome this limitation, a cost-effective technique called endoscopic tomographic velocimetry has been developed in this work. Read More

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http://dx.doi.org/10.1364/AO.58.001363DOI Listing
February 2019

Data-Driven Robust Control of Discrete-Time Uncertain Linear Systems via Off-Policy Reinforcement Learning.

IEEE Trans Neural Netw Learn Syst 2019 Mar 1. Epub 2019 Mar 1.

This paper presents a model-free solution to the robust stabilization problem of discrete-time linear dynamical systems with bounded and mismatched uncertainty. An optimal controller design method is derived to solve the robust control problem, which results in solving an algebraic Riccati equation (ARE). It is shown that the optimal controller obtained by solving the ARE can robustly stabilize the uncertain system. Read More

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http://dx.doi.org/10.1109/TNNLS.2019.2897814DOI Listing

[The influence of two calculation methods on the outcomes of Toric intraocular lenses].

Zhonghua Yan Ke Za Zhi 2019 Mar;55(3):208-213

Tianjin Medical University Eye Hospital, College of Optometry and Ophthalmology, Tianjin Medical University Eye Institute, Tianjin 300384, China.

To evaluate the influence of Barrett calculator and AcrySof calculator on astigmatism correction effect. This is a randomized prospective study. A total of 64 cases (81 eyes) who planed to undergo phacoemulsification at Tianjin Medical University Eye Hospital during January 2017 and March 2018 were enrolled and divided into two groups randomly, including of the Barrett calculator group of 34 cases (41 eyes) and the AcrySof calculator group of 30 cases (40 eyes). Read More

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http://dx.doi.org/10.3760/cma.j.issn.0412-4081.2019.03.010DOI Listing
March 2019
1 Read

White Box Implementations Using Non-Commutative Cryptography.

Authors:
Leandro Marin

Sensors (Basel) 2019 Mar 5;19(5). Epub 2019 Mar 5.

Area of Applied Mathematics (DITEC), Faculty of Computer Science, University of Murcia, 30071 Murcia, Spain.

In this paper, we present a method to create a safe arithmetic that can be used to obfuscate implementations that require operations over commutative groups. The method is based on the structure of the endomorphisms of certain extensions of the original commutative group. The endomorphisms of a commutative group are non-commutative (in general), thus we can use a non-commutative group to emulate the arithmetic of a commutative one. Read More

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http://dx.doi.org/10.3390/s19051122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6427245PMC

Corrosion Monitoring Method of Porous Aluminum Alloy Plate Hole Edges Based on Piezoelectric Sensors.

Sensors (Basel) 2019 Mar 5;19(5). Epub 2019 Mar 5.

School of Energy and Power Engineering, Beihang University, 37 Xueyuan Rd., Haidian Dist., Beijing 100191, China.

Corrosion damage to the aircraft structure can significantly reduce the safety performance and endanger flight safety. Especially when the corrosion occurs in a stress concentration region, such as hole edges, it can easily threaten the entire structure. In this paper, an on-line imaging qualitative monitoring algorithm based on piezoelectric sensors is proposed for detecting hole edge corrosion damage of porous aluminum alloy structures. Read More

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http://dx.doi.org/10.3390/s19051106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6427764PMC

Symbolic labeling in 5-month-old human infants.

Proc Natl Acad Sci U S A 2019 Mar 5;116(12):5805-5810. Epub 2019 Mar 5.

Cognitive Neuroimaging Unit U992, Institut National de la Santé et de la Recherche Médicale, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Direction de la Recherche Fondamentale/Institut Joliot, Université Paris-Saclay, NeuroSpin Center, 91191, Gif/Yvette, France.

Humans' ability to create and manipulate symbolic structures far exceeds that of other animals. We hypothesized that this ability rests on an early capacity to use arbitrary signs to represent any mental representation, even as abstract as an algebraic rule. In three experiments, we collected high-density EEG recordings while 150 5-month-old infants were presented with speech triplets characterized by their abstract syllabic structure-the location of syllable repetition-which predicted a following arbitrary label (e. Read More

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http://dx.doi.org/10.1073/pnas.1809144116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431210PMC
March 2019
6 Reads

Reasoning about clinical guidelines based on algebraic data types and constraint logic programming.

Authors:
Beatriz Pérez

J Biomed Inform 2019 Apr 1;92:103134. Epub 2019 Mar 1.

Department of Mathematics and Computer Science, University of La Rioja, C/ Madre de Dios 53 (Edificio Científico Tecnológico), E-26006 La Rioja, Spain. Electronic address:

Previously, the authors presented an overall framework aimed at improving the representation, quality and application of clinical guidelines in daily clinical practice. Regarding the quality improvement of guidelines, we developed a proposal to verify specific requirements in guidelines, using the SPIN model checker as verification tool. Additionally, we established a pattern-based approach for defining commonly occurring types of requirements in guidelines, in order to help non experts in their formal specification. Read More

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http://dx.doi.org/10.1016/j.jbi.2019.103134DOI Listing
April 2019
1 Read

Streaming PCA and Subspace Tracking: The Missing Data Case.

Proc IEEE Inst Electr Electron Eng 2018 Aug 23;106(8):1293-1310. Epub 2018 Jul 23.

John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA

For many modern applications in science and engineering, data are collected in a streaming fashion carrying time-varying information, and practitioners need to process them with a limited amount of memory and computational resources in a timely manner for decision making. This often is coupled with the missing data problem, such that only a small fraction of data attributes are observed. These complications impose significant, and unconventional, constraints on the problem of streaming Principal Component Analysis (PCA) and subspace tracking, which is an essential building block for many inference tasks in signal processing and machine learning. Read More

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http://dx.doi.org/10.1109/JPROC.2018.2847041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6395049PMC
August 2018
2 Reads

Can the original equations of a dynamical system be retrieved from observational time series?

Chaos 2019 Feb;29(2):023133

Centre d'Études Spatiales de la Biosphère, UPS-CNRS-CNES-INRA-IRD, Observatoire Midi-Pyrénées, 18 avenue Édouard Belin, 31401 Toulouse, France.

The aim of the present work is to investigate the possibility to retrieve the original sets of dynamical equations directly from observational time series when all the system variables are observed. Time series are generated from chosen dynamical systems, and the global modeling technique is applied to obtain optimal models of parsimonious structure from these time series. The obtained models are then compared to the original equations to investigate if the original equations can be retrieved. Read More

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http://dx.doi.org/10.1063/1.5081448DOI Listing
February 2019

An algebraic method to calculate parameter regions for constrained steady-state distribution in stochastic reaction networks.

Chaos 2019 Feb;29(2):023123

Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.

Steady state is an essential concept in reaction networks. Its stability reflects fundamental characteristics of several biological phenomena such as cellular signal transduction and gene expression. Because biochemical reactions occur at the cellular level, they are affected by unavoidable fluctuations. Read More

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http://dx.doi.org/10.1063/1.5047579DOI Listing
February 2019

The Pressor Response to Concurrent Stimulation of the Mesencephalic Locomotor Region and Peripheral Sensory Afferents Is Attenuated in Normotensive but Not Hypertensive Rats.

Front Physiol 2019 13;10:95. Epub 2019 Feb 13.

Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States.

Central command (CC) and the exercise pressor reflex (EPR) regulate blood pressure during exercise. We previously demonstrated that experimental stimulation of the CC and EPR pathways independently contribute to the exaggerated pressor response to exercise in hypertension. It is known that CC and EPR modify one another functionally. Read More

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http://dx.doi.org/10.3389/fphys.2019.00095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6381028PMC
February 2019

A computational model of epithelial solute and water transport along a human nephron.

PLoS Comput Biol 2019 02 25;15(2):e1006108. Epub 2019 Feb 25.

Department of Mathematics, Duke University, Durham, North Carolina, United States of America.

We have developed the first computational model of solute and water transport from Bowman space to the papillary tip of the nephron of a human kidney. The nephron is represented as a tubule lined by a layer of epithelial cells, with apical and basolateral transporters that vary according to cell type. The model is formulated for steady state, and consists of a large system of coupled ordinary differential equations and algebraic equations. Read More

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http://dx.doi.org/10.1371/journal.pcbi.1006108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6405173PMC
February 2019

: neutron and X-ray reflectometry analysis in Python.

J Appl Crystallogr 2019 Feb 1;52(Pt 1):193-200. Epub 2019 Feb 1.

School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia.

is a model-based neutron and X-ray reflectometry data analysis package written in Python. It is cross platform and has been tested on Linux, macOS and Windows. Its graphical user interface is browser based, through a notebook. Read More

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http://dx.doi.org/10.1107/S1600576718017296DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6362611PMC
February 2019

Generic Primitive Detection in Point Clouds Using Novel Minimal Quadric Fits.

IEEE Trans Pattern Anal Mach Intell 2019 Feb 19. Epub 2019 Feb 19.

We present a novel and effective method for detecting 3D primitives in cluttered, unorganized point clouds, without axillary segmentation or type specification. We consider the quadric surfaces for encapsulating the basic building blocks of our environments in a unified fashion. We begin by contributing two novel quadric fits targeting 3D point sets that are endowed with tangent space information. Read More

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http://dx.doi.org/10.1109/TPAMI.2019.2900309DOI Listing
February 2019
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Optimization Tools Based on Metaheuristics for Performance Enhancement in a Gaussian Adaptive PID Controller.

IEEE Trans Cybern 2019 Feb 15. Epub 2019 Feb 15.

This paper presents the proposal of using two bio-inspired metaheuristics--genetic algorithms (GAs) and particle swarm optimization (PSO)--to adjust the free coefficients of a Gaussian adaptive proportional-integral-derivative (GAPID) controller. When a specific adaptation rule is imposed to a conventional proportional-integral-derivative (PID) controller, either by means of a hyperbolic tangent function or a Gaussian function, the solution is left exposed to the function restrictions/impositions. Finding the correct proportionality between the parameters is an arduous task, which often does not have an algebraic solution. Read More

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http://dx.doi.org/10.1109/TCYB.2019.2895319DOI Listing
February 2019
2 Reads

Multistationarity in Structured Reaction Networks.

Bull Math Biol 2019 May 20;81(5):1527-1581. Epub 2019 Feb 20.

Department of Mathematics, Texas A&M University, College Station, TX, 77843, USA.

Many dynamical systems arising in biology and other areas exhibit multistationarity (two or more positive steady states with the same conserved quantities). Although deciding multistationarity for a polynomial dynamical system is an effective question in real algebraic geometry, it is in general difficult to determine whether a given network can give rise to a multistationary system, and if so, to identify witnesses to multistationarity, that is, specific parameter values for which the system exhibits multiple steady states. Here we investigate both problems. Read More

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http://dx.doi.org/10.1007/s11538-019-00572-6DOI Listing

Solving matrix equations in one step with cross-point resistive arrays.

Proc Natl Acad Sci U S A 2019 Feb 19. Epub 2019 Feb 19.

Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy

Conventional digital computers can execute advanced operations by a sequence of elementary Boolean functions of 2 or more bits. As a result, complicated tasks such as solving a linear system or solving a differential equation require a large number of computing steps and an extensive use of memory units to store individual bits. To accelerate the execution of such advanced tasks, in-memory computing with resistive memories provides a promising avenue, thanks to analog data storage and physical computation in the memory. Read More

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http://dx.doi.org/10.1073/pnas.1815682116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6410822PMC
February 2019
9.809 Impact Factor

Specific heat and partition function zeros for the dimer model on the checkerboard B lattice: Finite-size effects.

Phys Rev E 2019 Jan;99(1-1):012102

Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan.

There are three possible classifications of the dimer weights on the bonds of the checkerboard lattice and they are denoted as checkerboard A, B, and C lattices [Phys. Rev. E 91, 062139 (2015)PLEEE81539-375510. Read More

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http://dx.doi.org/10.1103/PhysRevE.99.012102DOI Listing
January 2019

McSART: an iterative model-based, motion-compensated SART algorithm for CBCT reconstruction.

Phys Med Biol 2019 Feb 18. Epub 2019 Feb 18.

Radiation Oncology, University of California Los Angeles David Geffen School of Medicine, 200 Medical Plaza, Suite B265, Los Angeles, California, 90095, UNITED STATES.

4D cone beam computed tomography (CBCT) images of the thorax and abdomen can have reduced quality due to the limited number of projections per respiratory bin used in gated image reconstruction. In this work, we present a new algorithm to reconstruct high quality CBCT images by simultaneously reconstructing images and generating an associated respiratory motion model. This is done by updating model parameters to compensate for motion during the iterative image reconstruction process. Read More

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http://dx.doi.org/10.1088/1361-6560/ab07d6DOI Listing
February 2019
1 Read

Stability analysis of Cohen-Grossberg neural networks of neutral-type: Multiple delays case.

Authors:
Neyir Ozcan

Neural Netw 2019 May 6;113:20-27. Epub 2019 Feb 6.

Department of Electrical and Electronics Engineering, Faculty of Engineering, Bursa Uludag University, Bursa, Turkey. Electronic address:

The essential purpose of this work is to conduct an investigation into stability problem for the class of neutral-type Cohen-Grossberg neural networks including multiple time delays in states and multiple neutral delays in time derivative of states. By proposing an appropriate Lyapunov functional, a new sufficient criterion is derived for global asymptotic stability of neutral-type neural networks. The obtained stability criterion is independent of time delay and neutral delay parameters, and it is completely stated in terms of the elements of interconnection matrices and other network parameters. Read More

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http://dx.doi.org/10.1016/j.neunet.2019.01.017DOI Listing