Miracle-dz/UniFAR-FTUs huggingface dataset:
A Comparison of Time Domain VS Frequency Domain Delay and Sum Beamforming for Underwater 3D Acoustical Imaging

Digital delay and sum beamforming is the promising technique for underwater 3D acoustical imaging. Even though time domain delay and sum beamforming is widely used for medical ultrasound imaging, it is hardly used for underwater acoustical 3D imaging. The conventional narrowband transmit coupled with the computational complexity required for the implementation of interpolation filter is the major reason for that. However, with the increasing popularity of wideband and ultrawideband transmission for achieving high resolution imaging and with the availability of efficient software interpolation libraries in modern computing systems, the computational time required for frequency domain beamforming appears to be more than that of time domain beamforming. Thus, through this work, we have attempted to compare the frequency domain vs time domain delay and sum beamforming for wideband underwater 3D acoustical imaging. The simulation findings demonstrated that time domain DAS beamforming is faster, computationally effective, memory-efficient, and offers somewhat superior image quality.
Parabolic optimal control problems on evolving surfaces subject to point-wise box constraints on the control – theory and numerical realization

We consider control-constrained linear-quadratic optimal control problems on evolving hypersurfaces in RnC1. In order to formulate well-posed problems, we prove existence and uniqueness of weak solutions for the state equation, in the sense of vector-valued distributions. We then carry out and prove convergence of the variational discretization of a distributed optimal control problem. In the process, we investigate the convergence of a fully discrete approximation of the state equation, and obtain optimal orders of convergence under weak regularity assumptions. We conclude with a numerical example.
Solving large‑scale reactive optimal power flow problems by a primal–dual M 2 BF approach

In this paper, we propose a predictor–corrector primal–dual approach for the doubly modified logarithmic barrier function ( M 2 BF ) method in order to solve Optimal Reactive Power Flow (ORPF) problems. The M 2 BF is a modification of the Polyak’s modified logarithmic barrier function (MBF) and is also a particular element of a recent family of nonquadratic penalty functions for augmented Lagrangian methods for handling convex problems only with inequality constraints. We also propose a global convergence strategy to be inserted in the proposed algorithm, which is developed over weak assumptions concerning the primal Hessian matrix. The result-ing predictor–corrector primal–dual M 2 BF approach is applied for solving ORPF problems involving power systems with 57, 89, 118, 200, 300, 1354, 2007 and 2869 buses. A comparison with two state-of-the-art methods is performed. Numerical results show that the proposed approach is competitive and capable of solving ORPF problems for small to large-scale power systems.
Treatment effect measures when using recurrent event endpoints – Qualification Opinion List of Issues regarding provided simulation exercises

Summary A request for a qualification opinion entitled “Clinically interpretable treatment effect measures based on recurrent event endpoints that allow for efficient statistical analyses” has been issued by a number of renowned statisticians. The request is centred on two examples (relapsing remitting multiple sclerosis (rrMS) and chronic heart failure (CHF)) representing situations where recurrent event analyses may offer opportunities to describe a clinically relevant treatment effect. Whereas in the first example recurrent event analyses for relapses have been used for decision making during drug licensing, experiences are still limited with the use of recurrent re-hospitalisations for worsening heart failure in the latter indication that is distinct in that death is still frequent in heart failure studies. From a statistical perspective the intercurrent event “death” obviously censors further observation of the recurrent event endpoint under investigation, but additional consideration should be given to the fact that further re-hospitalisations are impossible and the time-point of censoring is not just a lower boundary for the time to the next rehospitalisation to be observed.
High Resolution Transmission Electron Microscopy Study on the Structure of Ge Nanoparticles by Using an Ultrahigh Vacuum-Molecular Beam Epitaxy-Transmission Electron Microscope System

Ge nanoparticles were deposited on thinned Si substrates in an ultrahigh vacuum molecular beam epitaxy instrument (UHV-MBE) and transferred into an UHV-field emission transmission electron microscope (UHV-FE-TEM) through an UHV-transferring system. TEM observation indicated that the Ge nanoparticles had a round shape and were 2 to 5 nm in diameter. The crystalline Ge nanoparticles exhibited single crystals, single-twinned crystals, and decahedral multi-twinned particles (MTPs). It was found that the crystal structure of some nanoparticles changes from a diamond structure to a novel structure, which is proposed to be a β-Sn structure, with a=0.38 nm and c=0.71 nm. The particles with the new structure are not formed when the substrate temperature is above 370°C. The structure of MTPs has been discussed. Some Ge nanocrystals even became amorphous and then fluctuated continually during HRTEM observation.
L 2 -gain analysis and output feedback control for continuous-time switched systems with actuator saturation

This paper is concerned with the problem of L 2 -gain analysis for a class of continuous-time switched systems with actuator saturation. Different from the existing results using the state-dependent switching approach, a linear parameter-varying output feedback controller with the time-dependent switching mechanism is designed such that the overall system is exponentially stable and with disturbance tolerance capacity and L 2 gain. Further, the proposed controller is insured by introducing the slack matrices to have less conservatism, which maximizes the ellipsoid where the state trajectories starting from the origin will remain. Sufﬁcient conditions for the existence of the switching and output feedback control law are derived in terms of linear matrix inequalities. Finally, a practical example is given to show the effectiveness of the proposed method.
On stable iterative methods of gradient type for the inverse medium scattering problem

In this article we present a class of iterative methods for the inverse problem of 3D acoustic scattering on a penetrable inhomogeneity. We formulate the problem as an ill-posed nonlinear operator equation in a Hilbert space. The proposed methods are based on an approximation of this equation by a strongly convex finite-dimensional variational problem. The strong convexity of the approximating problem plays the key role in a theoretical justification of our approach to numerical approximation of solutions to ill-posed problems. Specifically, this property ensures the stability of the proposed iterative methods with respect to the errors in input data as an iteration number increases. We also present results of computational experiments.
A stabilized finite element formulation for high‐speed inviscid compressible flows using finite calculus

This paper aims at the development of a new stabilization formulation based on the finite calculus (FIC) scheme for solving the Euler equations using the Galerkin FEM on unstructured triangular grids. The FIC method is based on expressing the balance of fluxes in a space–time domain of finite size. It is used to prevent the creation of instabilities typically present in numerical solutions due to the high convective terms and sharp gradients. Two stabilization terms, respectively called streamline term and transverse term, are added via the FIC formulation to the original conservative equations in the space–time domain. An explicit fourth‐order Runge–Kutta scheme is implemented to advance the solution in time. The presented numerical test examples for inviscid flows prove the ability of the proposed stabilization technique for providing appropriate solutions especially near shock waves. Although the derived methodology delivers precise results with a nearly coarse mesh, a mesh refinement technique is coupled to the solution process for obtaining a suitable mesh particularly in the high‐gradient zones. Copyright © 2014 John Wiley & Sons, Ltd.
Generalization of Geometry-Induced Gauge Structure to Any Dimensional Manifold

We investigate a particle motion quantum-mechanically in the neighbourhood of n-dimensional curved manifold M n embedded in a p-dimensional Euclidean space R p . The effective Hamiltonian on M n has a gauge structure determined by geometry of M n , generally non-Abelian. This gives a generalization of the geometry-induced Aharonov-Bohm effect in the case M 1 ⊂ R 3
Wavefunctions, expectation values and scars on Poincaré sections - a scattering approach

Using the scattering approach to quantization, we define an appropriate representation of the billiard wavefunction on the scattering Poincar? section. The expectation values of smooth operators in terms of these Poincar? section wavefunctions are expressed as sums over periodic orbits. A special operator is used to define scars on the section and the relation to scars in configuration space is discussed and demonstrated numerically.
On the effects of the damping mechanisms in an atmospheric general circulation model

A version of ECMWF's first spectral model with a comprehensive physical parameterization package has been used for long-term integrations in perpetual January mode. The model has 9 sigma-levels in the vertical and the expansion of the horizontal fields are truncated at total wavenumber n = 31. In order to simulate the observed January climate both in terms of mean-fields as well as the spectral distribution of the kinetic energy as accurately as possible, a series of experiments has been performed with varying parameterizations of some physical processes, especially the damping mechanisms. The inclusion of a simple gravity wave drag is found to have a substantial impact on the simulations. The position and depth of the mean sea level quasi-stationary low pressures in the northern hemisphere is more in accordance with their observed counterparts with the gravity wave drag included, and the excessive stratospheric polar night jet, which is developed in the model without the drag, is effectively controlled by this parameterization. The sensitivity due to changes in the vertical diffusion of momentum, heat and moisture has been considered by crude variations in the mixing length. It turns out that even large changes in the value of the mixing length have a quite modest influence on the mean fields simulated by the model. The horizontal diffusion is necessary in order to represent the effect of the unresolved scales on the explicitly predicted scales. The parameterization of this effect is incorporated in the model as a linear term utilizing that in a spectral formulation, a linear diffusion can easily be formulated with any scale dependency. It is found that an increase of the diffusion in the smallest scales may result in an increase of eddy kinetic energy of the larger scales and even an increase in the total eddy kinetic energy. Moreover it appears that it is quite possible to formulate the linear diffusion of the model to simulate the observed spectral variations of kinetic energy for the medium and smaller scales. DOI: 10.1111/j.1600-0870.1989. tb00390.x
Improved Retinal Microcirculation After Cardiac Surgery in Patients With Congenital Heart Disease

Background: Microcirculatory changes in congenital heart disease (CHD) patients undergoing cardiac surgery are not fully understood. We aimed to investigate the changes of retinal microcirculation in CHD patients after cardiac surgery by optical coherence tomography angiography (OCTA) and explore the association between retinal microcirculation and surgical outcome. Methods: This prospective observational study consisted of 71 CHD patients aged ≥6 years undergoing cardiac surgery including 19 cyanotic CHD (CCHD) and 52 acyanotic CHD (ACHD). Optical coherence tomography angiography (OCTA) was used to measure vessel density (VD) and capillary density (CD) of radial peripapillary capillary (RPC) and peripapillary, VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP), thickness of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) preoperatively and 1 month postoperatively. Transthoracic echocardiography was conducted to measure macrocirculation. Results: In CCHD patients, VD and CD of RPC and peripapillary increased postoperatively (all P < 0.05). In ACHD patients, VD of peripapillary, CD of RPC and peripapillary, and RNFL thickness increased postoperatively (all P < 0.05). VD of SCP and DCP, and GCC thickness did not change significantly in CHD patients after surgery. Lower preoperative retinal microvascular density was associated with longer cardiopulmonary bypass (CPB) time and postoperative length of stay (PLOS). No correlation was found between microcirculatory and macrohemodynamic parameters (all P > 0.05). Conclusions: Improved retinal microcirculation was observed after congenital cardiac surgery and impaired preoperative retinal microvasculature was associated with prolonged CPB time and PLOS, which might provide potential information about the outcome of congenital cardiac surgery.
A Fast Convergent Adaptive-K Mixture-Of-Gaussian Model for Video Object Segmentation

It is a key step to extract moving objects from background for computer vision applications. GMM based methods are the most commonly used technique for background subtraction in video sequence. However, how to establish efficient and precision background model with fast convergence rate is a Research-Worthy problem. In this paper, an effective scheme is proposed to accelerate the convergence rate of Adaptive-K Gaussian Mixture Model (AKGMM). The AKGMM algorithm alters the dimension of the parameter space at each pixel based on the changing frequency of pixel value. The number of GMM reflects the complexity of pattern at the pixel. An improved learning method is proposed for Gaussian Mixture Model. An adaptive learning rate is calculated for each Gaussian at every frame for speeding up the convergence without compromising model stability. Experimental results demonstrated that the proposed method gets a faster convergence while maintaining good robustness against complex environment compared to a conventional method.
An Optimization-Based Domain Decomposition Method for a Two-Body Contact Problem

Abstract We study a domain decomposition method for the numerical simulation of a two-body contact problem in two-dimensional linear elasticity. The problem is restated as a decomposition-coordination problem by introducing a smooth fictitious rigid surface between the two elastic bodies. In the decomposition step, two independent problems are solved: a Signorini-like problem and a prescribed displacement problem. In the coordination step, the fictitious rigid surface is adjusted to minimize a auxiliary functional.
Local magnetic properties of L × L square lattice with an Extended Hubbard Model

Within an analytical diagonalization, it is possible to exactly solve a large class of models useful for the study of strongly correlated electrons systems. Here, we perform an exact diagonalization of the two-dimensional Extended Hubbard Model with ﬁrst nearest neighbor repulsive V and spin-spin interaction J at one-eight ﬁlling. The analysis of the ground state energy and spin gap behaviors as a function of V and J terms allows us to study some local magnetic properties of 2 D ferromagnetic correlated electrons system distributed in ﬁnite square lattice. The obtained results show the existence of competition between Spin Density Wave and Charge Density Wave with the possibility to have a phase transition between these two waves at a critical value V c
Improved tan / n ð Þ 2 (cid:2) (cid:3) -expansion method for (2 + 1)-dimensional KP–BBM wave equation

An improved tan / n ð Þ 2 (cid:2) (cid:3) -expansion method has been implemented to solve (2 ? 1)-dimensional KP–BBM wave equation. Several types of exact particular solutions with parameters are obtained. Those includes hyperbolic function solutions, trigonometric function solutions, and rational solutions. From our work it is evident that the improved technique provide more verities of solutions and that too with less computational work.
Robust event-triggered H ∞ controller design for vehicle active suspension systems

In this paper, we investigate the event-triggered H ∞ controller synthesis issue for vehicle sus-pensionsystemswithlinearfractionaluncertainties.An active suspension model of quarter-car is represented by the state-space form. In order to obtain a resource-aware state feedback controller for the system, we pro-pose an event-triggered communication mechanism to check which measurements should be delivered to the controller for updating the control input. Together with the proposed event threshold condition, a piecewise continuous bounded function is introduced to model the intermittent updating intervals. Employing the Lyapunov functional method, we present a stability crite-rion for the controlled event-triggered active suspension system under parameter uncertainties and some physical constraints. Then, a design method for the event-triggered controller gain is obtained by utilizing some matrix transformations. An example is ﬁnally employed to illustrate the validness of the proposed method.
Towards Inspection and Cleaning on Capacitor Towers: Design and Implementation of Multi-task Operation Robot

Capacitors work in harsh environments, including strong electric fields, strong mechanical stress, and drastic weather changes for a long time. Solid, liquid, and gaseous dirt particles will be deposited on the surface of the electrical outer insulations, the electrical strength of the capacitor will be greatly reduced, and the health condition of the capacitor tower will deteriorate under the effect of harsh weather conditions, such as fog, dew, drizzle, and melting ice (snow). Based on the importance of the safe operation of substations, it is necessary to regularly evaluate the health condition of capacitors and complete operational tasks such as insulator cleaning, bolt tightening, and capacitance measurement. Considering the above situation and needs, we propose a solution of inspection and maintenance robot for capacitor towers in high-voltage substations by using automatic and intelligent technology to complete the above-mentioned tasks efficiently and reliably instead of manual work.
Uncovering Diagnostic Value of Mitogenome for Identification of Cryptic Species Fusarium graminearum Sensu Stricto

Fungal complexes are often composed of morphologically nearly indistinguishable species with high genetic similarity. However, despite their close relationship, they can exhibit distinct phenotypic differences in pathogenicity and production of mycotoxins. Many plant pathogenic and toxigenic fungi have been shown to consist of such cryptic species. Identification of cryptic species in economically important pathogens has added value in epidemiologic studies and provides opportunities for better control. Analysis of mitochondrial genomes or mitogenomics opens up dimensions for improved diagnostics of fungi, especially when efficient recovery of DNA is problematic. In comparison to nuclear DNA, mitochondrial DNA (mtDNA) can be amplified with improved efficacy due to its multi-copy nature. However, to date, only a few studies have demonstrated the usefulness of mtDNA for identification of cryptic species within fungal complexes. In this study, we explored the value of mtDNA for identification of one of the most important cereal pathogens Fusarium graminearum sensu stricto (F.g.). We found that homing endonucleases (HEGs), which are widely distributed in mitogenomes of fungi, display small indel polymorphism, proven to be potentially species specific. The resulting small differences in their lengths may facilitate further differentiation of F.g. from the other cryptic species belonging to F. graminearum species complex. We also explored the value of SNP analysis of the mitogenome for typing F.g. The success in identifying F.g. strains was estimated at 96%, making this tool an attractive complement to other techniques for identification of F.g.
Multiple fault diagnosis for rolling bearings method employing CEEMD-GCN based on horizontal visibility graph

Multiple faults often occur in the operation of rotating machinery transmission systems. The fault signals of multiple bearings interfere with each other, which makes feature extraction and diagnosis of complex compound fault signals difficult. Because the graph convolution networks (GCN) can effectively map the structural information from complex data and its model has a certain generalization ability, this paper proposes a multiple fault diagnosis method for rolling bearings employing complete ensemble empirical mode decomposition (CEEMD) and a GCN (CEEMD-GCN) based on a horizontal visibility graph (HVG). Firstly, in order to highlight the effective feature information in the multiple fault signal and reduce noise interference, multiple indicators of correlation and kurtosis are used to reconstruct the decomposed signals through CEEMD; secondly, the reconstructed signals are constructed as an HVG, and the HVG maps the time series signal to the graphic structure data, reflecting the local geometric characteristics of the vibration signal through the horizontal visibility relationship; finally, taking the signal samples obtained by the HVG algorithm as the input data of the model, the GCN model is trained to realize the diagnosis of multiple faults. The experimental results show that the presented methodology is superior to other methods and exhibits generalization ability for multiple fault diagnosis.
The delta-corrected Kolmogorov-Smirnov test for the two-parameter Weibull distribution

Monte Carlo simulation techniques are used to create tables of critical values for the delta-corrected Kolmogorov-Smirnov statistic-a modification of the classical Kolmogorov-Smirnov statistic-for the Weibull distribution with known location parameter and unknown shape and scale parameters. The power of the proposed test is investigated relative to values of delta in the unit interval and relative to a wide variety of alternative distributions. The results indicate that using the delta-correction can lead to as many as 8.4 percentage points more power than can be achieved with the classical Kolmogorov-Smirnov test, with no change in the size of the test. Furthermore, carrying out the delta-corrected test involves no more steps or calculations than for the classical Kolmogorov-Smirnov test. In general, it is shown that a slight modification-or correction-in the definition of the empirical distribution function of the Kolmogorov-Smirnov test can lead to power enhancement without changing the type I error rate of the test. Two examples clearly show the effectiveness of the delta-corrected test. The delta-corrected Kolmogorov-Smirnov test is recommended for testing the goodness of fit to the twoparameter Weibull distribution.