Miracle-dz/UniFAR-FTUs huggingface dataset:
Integrated 2D-3D free surface hydro-environmental modelling

An integrated horizontally two- and fully three-dimensional numerical model system has been developed based on a combined unstructured and σ-coordinate grid to simulate the flow and water quality process in large water bodies with a focus on the three dimensional behaviours at specific areas. The model is based on the time dependent Reynolds-Averaged Navier-Stokes equations with a non-hydrostatic pressure distribution and a baroclinic force being incorporated in the three dimensional (3D) model. The two sub models interact dynamically during the solution procedure with no time-step restriction due to integration. The main idea is to use a fractional step algorithm for each model and then integrate the two models fraction by fraction. Hybrid 2D-3D finite volume cells have been introduced for the link nodes which are partly in the 2D domain and partly in the 3D domain. Thus an interpolation/averaging procedure at the interface and domain overlapping is no longer needed. The 3D model uses the projection method for pressure calculation. The advection equation is solved by the semi-Lagrangian method. Other components are solved via the finite element - finite volume (FV) method. The water surface is determined implicitly through a global matrix equation created by assembling the domain's matrices. The cell integrals are calculated analytically to eliminate a common source of numerical diffusion due to the use of approximation techniques for the FV integrals. The horizontal gradients of the density and shear stresses are calculated on true horizontal planes, in order to avoid artificial velocity and diffusion in highly stratified flows. Neumann interpolation elements with virtual nodes have been introduced at Neumann type of boundaries for more accuracy. The integrated model has been verified using analytical solutions and benchmark test cases, including the Ekman velocity distribution, wind driven circulation, lock exchange and integrated 2D-3D flows in basin. The results show the model is capable of the model for accurate simulation and implicit 2D-3D integration. Keywords: integrated modelling, hydrodynamic numerical model, non-hydrostatic, unstructured mesh, hybrid finite element finite volume method.
New Structural Model of an Al72Ni20Co8 Decagonal Quasicrystal.

A new structural model of an Al 72 Ni 20 Co 8 decagonal quasicrystal is constructed on the basis of high-angle annular dark-field images and high-resolution electron microscope images. The model is composed of two types of atom clusters with about a 0.4 nm radius as basic structural units, which are similar to the unit existing in the Al 13 Fe 4 monoclinic approximant. The two clusters are located at the lattice points of the rhombic Penrose lattice. The model satisfies the symmetry of space group P 10 5 / m m c . High-resolution electron microscope images calculated from the model agree well with the experimental ones.
An approach toward defining L-fuzzy lattices

The paper deals with one possible approach that can be used in the process of defining lattice valued fuzzy lattice (L-fuzzy lattice). The idea of fuzzification of the ordering of a crisp lattice to obtain a weakly reflexive lattice valued ordering relation is developed in order to obtain a structure whose level sets are crisp lattices. At this point, two different treatments of the problem can be effectuated, and therefore two definitions of L-fuzzy lattices can be offered. The theorems for synthesis of those structures are also given, as well as an illustrating example.
Coupled Painlevé systems and quartic potentials

Similarity reductions of the Hirota-Satsuma system and another gauge-related system yield non-autonomous Hamiltonian systems with quartic potentials. We present classes of special solutions and Bäcklund transformations which are interpreted in terms of the action of an affine Weyl group on the space of parameters. Some other quartic oscillators related to coupled Painlevé-type equations are briefly considered. We show how separation of variables also has an application in this context.
α-flips and T-points in the Lorenz system

We consider the Lorenz system near the classic parameter regime and study the phenomenon we call an α-flip. An α-flip is a transition where the one-dimensional stable manifolds Ws(p±) of two secondary equilibria p± undergo a sudden transition in terms of the direction from which they approach p±. This is a bifurcation at infinity and does not involve an invariant object in phase space. This fact was discovered by Sparrow in the 1980s but the stages of the transition could not be calculated and the phenomenon was not well understood (Sparrow 1982 The Lorenz equations (New York: Springer)). Here we employ a boundary value problem set-up and use pseudo-arclength continuation in AUTO to follow this sudden transition of Ws(p±) as a continuous family of orbit segments. In this way, we geometrically characterize and determine the moment of the actual α-flip. We also investigate how the α-flip takes place relative to the two-dimensional stable manifold of the origin, which shows no apparent topological change before or after the α-flip. Our approach allows for easy detection and subsequent two-parameter continuation of the first and further α-flips. We illustrate this for the first 25 α-flips and find that they end at terminal points, or T-points, where there is a heteroclinic connection from the secondary equilibria to the origin. It turns out that α-flips must occur naturally near T-points. We find scaling relations for the α-flips and T-points that allow us to predict further such bifurcations and to improve the efficiency of our computations.
A System for Automating the Detection and Counting of Frogs in Small Passages

—The aim of this project is to classify and count frogs that pass subterranean passages. To solve this problem, we took two diﬀerent approaches: the ﬁrst one uses image classiﬁcation with ResNet [1], the second approach builds upon the YOLOv5 [2] object detection algorithm.
KINEMATICS OF THE TIDAL DEBRIS OF THE GLOBULAR CLUSTER PALOMAR 5

This paper presents the first observational study of the kinematics of debris from a disrupting globular cluster. Seventy-four bright member candidates of the tidal stream of the cluster Palomar 5, spread over an arc of 8. °5 on the sky, have been observed using high-resolution spectroscopy on the VLT and 17 of them were identified as members of the stream. Their velocities are very close to the radial velocity of the cluster and show a linear trend with position along the stream. We measure the local gradient of the line-of-sight velocity along the stream to be 1.0 ± 0.4 km s−1 deg−1. The stars in the stream show an overall velocity dispersion of 4.7 km s−1, which reduces to only 2.2 km s−1 when removing two stars. This demonstrates that the tidal debris from Pal 5 forms a kinematically cold structure in the Galactic halo, and hence explains the narrowness of the tails. The velocity gradient along the stream provides an important constraint on the orbit of the cluster and thus also on the potential in the Galactic halo. This leads to the conclusion that, in contrast to what was assumed in earlier studies, the cluster's orbit on the sky is not exactly aligned with its tidal tails. A revised model for the orbit of Pal 5 is thus proposed.
Commutation Properties of Cyclic and Null Killing Symmetries

In a space‐time admitting cyclic and nonspacelike Killing symmetries the commutation properties of the Killing vectors are examined. It is shown that cyclic and null Killing vectors can be noncommuting only if a Killing vector of stationarity is also admitted. Two consequences of this commutativity are also discussed.
Novel concept for large deformable mirrors

Large, high-bandwidth deformable mirrors (DMs) with thousands of actuators for adaptive optics are of high interest for existing large telescopes and indispensable for construction of efficient future extremely large telescopes. Different actuation and sensing principles are possible. We propose a novel concept using commercially available voice coil actuators attached to the back of the mirror with suction cups and using LVDT sensors on the actuators for local stabilization. Also, a new low-cost sensor for easy measurement of DM displacement or velocity has been developed. It has a sensitivity better than 20 nm and a bandwidth wider than 20 to 1000 Hz. Finally, studies are in progress of global, hierarchical mirror form controllers based on many parallel multiple-input, multiple-output regulators of low order.
SLIP-WEAKENING FRICTION INSTABILITIES: EIGENVALUE ANALYSIS

We consider the evolution problem for the wave equation with nonlinear boundary conditions, modeling the anti-plane shearing on a system of finite faults under a slip-dependent friction in a linear elastic continuum. The associated eigenvalue problem is studied for bounded and unbounded domains. Recent studies showed that this eigenvalue problem plays a key role in earthquake nucleation modeling. We investigate the structure of the positive eigenvalues set and prove the monotone dependence of the first eigenvalue on the friction parameter. For the elastic plane with a collinear system of faults, the eigenvalue problem is reduced to a hyper-singular integral equation. This equation is solved through a semi-analytical technique. Numerical results show a sensible dependence of the first eigenfunction on the geometry and friction heterogeneity.
Assessment of two a posteriori error estimators for elasticity problems

The main focus of this paper is on the evaluation of local a posteriori error estimation techniques for the finite element method (FEM). The standard error estimation techniques are presented for the coupled displacement fields appearing in elasticity problems. The two error estimators, the element residual method (ERM) and Zienkiewicz–Zhu (ZZ) patch recovery technique, are evaluated numerically and then used as drivers for a mesh adaptation process. The results demonstrate the advantages of employing a posteriori error estimators for obtaining finite element solutions with a pre-specified error tolerance. Of the two methods, the ERM is shown to produce adapted meshes that are similar to those adapted by the exact error. Furthermore, the ERM provides higher quality estimates of the error in the global energy norm when compared to the ZZ estimator.
The three-dimensional transition in the flow around a rotating cylinder

The flow around a circular cylinder rotating with a constant angular velocity, placed in a uniform stream, is investigated by means of two- and three-dimensional direct numerical simulations. The successive changes in the flow pattern are studied as a function of the rotation rate. Suppression of vortex shedding occurs as the rotation rate increases (>2). A second kind of instabilty appears for higher rotation speed where a series of counter-clockwise vortices is shed in the upper shear layer. Three-dimensional computations are carried out to analyse the three-dimensional transition under the effect of rotation for low rotation rates. The rotation attenuates the secondary instability and increases the critical Reynolds number for the appearance of this instability. The linear and nonlinear parts of the three-dimensional transition have been quantified by means of the amplitude evolution versus time, using the Landau global oscillator model. Proper orthogonal decomposition of the three-dimensional fields allowed identification of the most energetic modes and three-dimensional flow reconstruction involving a reduced number of modes.
Computations of lossy Bloch waves in two-dimensional photonic crystals

In this article we compute lossy Bloch waves in two-dimensional photonic crystals with dispersion and material loss. For given frequencies these waves are determined from non-linear eigenvalue problems in the wave vector. We applied two numerical methods to a demanding test case, a photonic crystal with embedded quantum dots that exhibits very strong and anamolous dispersion. The first method is based on the formulation with periodic boundary conditions leading to a quadratic eigenvalue problem. We discretize this problem by the finite element method (FEM), first of quadratic order and, second, of higher orders using curved cells (p-FEM). Second, we use the multiple-multipole method (MMP) with artificial sources and compute extrema in the field response determining the eigenvalues. Both MMP and FEM provide robust solutions for the investigated dispersive and lossy photonic crystal, and can approximate the Bloch waves to a high accuracy. Moreover, the MMP method and p-FEM show low computational effort for very accurate solutions.
Urban building roof segmentation from airborne lidar point clouds

This article presents a new approach to segmenting building rooftops from airborne lidar point clouds. A progressive morphological filter technique is first applied for separation between ground and non-ground points. For the non-ground points, a region-growing algorithm based on a plane-fitting technique is used to separate building points from vegetation points. Then, an adaptive Random Sample Consensus (RANSAC) algorithm based on a grid structure is developed to improve the probability of selecting an uncontained sample from the localized sampling. The distance, standard deviation and normal vector are integrated to keep topological consistency among building rooftop patches during building rooftop segmentation. Finally, the remaining points are mapped on to the extracted planes by a post-processing technique to improve the segmentation accuracy. The results for buildings with different roof complexities are presented and evaluated.
Real-time single-shot full-field OCT based on dual-channel phase-stepper optics and 2D quaternionic analytic signal processing

We describe a novel compact real-time single-shot full-field optical coherence tomography based on a dual-channel phase-stepper optics, which employs a 2-D quaternionic analytic signal processing technique to reconstruct the en-face OCT image. The experimental setup was based on a Linnik type polarization Michelson interferometer followed by a dual-channel phase-stepper optics and a single CCD camera to capture two 180° phase stepped images simultaneously. The interferometer is illuminated using a SLD source with central wavelength of 842 nm and spectral bandwidth of 16.2 nm, yielding an axial resolution of 19.8 μm. Using a 10 X (0.25-NA) microscope objective and a single CCD camera, the system covers an area of 325μm x 300μm (325 × 300 pixels) with a transverse resolution of 4.4 μm. We demonstrate the feasibility of this system for real-time imaging of scattering specimens such as a diaptomus.
Unsupervised flaw segmentation in textile materials under visible and NIR illumination

An unsupervised novelty detection method for automatic flaw segmentation in textile materials that has no need of any defect-free references or a training stage is presented in this paper. The algorithm is based on the structural feature extraction of the weave repeat from the Fourier transform of the sample image. These features are used to define a set of multiresolution bandpass filters adapted to the fabric structure that operate in the Fourier domain. Inverse Fourier transformation, binarization and merging of the information obtained at different scales lead to the output image that contains flaws segmented from the fabric background. The whole process is fully automatic and can be implemented either optical or electronically. Fabrics having a superstructure of colored squares, bands, etc. superimposed to the basic web structure can be advantageously analyzed using NIR illumination and a camera sensitive to this region of the spectrum. The contrast reduction of the superstructure signal in the NIR image facilitates fabric structure inspection and defect segmentation. Underdetection and misdetection errors can be noticeably reduced in comparison with the inspection performed under visible illumination. Experimental results are presented and discussed for a variety of fabrics and defects.
POLES AND ZEROS OF MULTIVARIABLE LINEAR TIME-VARYING SYSTEMS

Abstract In the paper it is shown that the pole set of a linear system can be calculated by suitable polynomial factorizations. The theoretical issues related to poles and zeros of time-varying systems are discussed. Further, it is shown how the poles and zeros can be defined starting from a state-space realization of the input-output system.
Observations of the Type II Supernova 1986I in M99

We report spectroscopic and photometric results on a supernova in M99, SN19861, from first detection to several months after the explosion. This supernova is distinct from other supemov~ (except possibly SN1987A in the LMC) in that it exhibits strong Ha emission in the early spectra, less than 10 days after it exploded. The spectra also show an ultraviolet deficit below the blackbody extrapolated from longer wavelengths. The light curves in V, R, and I dropped slowly during the first few months after detection, resembling a Type IT "plateau" supernova, and dropped precipitously near 200 days past maximum. We have also measured the wavelengths and velocities of the stronger emission and absorption features, with tentative identifications.
A hands-on introduction to molecular dynamics

We present an introduction to the chemical and computational aspects of the molecular dynamics (MD) simulation technique. Using just a few elementary ideas from classical mechanics and numerical analysis, and linear chains of identical particles as example systems, we take the reader through the steps required for the design and analysis of a simple molecular dynamics experiment. We employ the Hooke's law model for the interactions between the particles since its visualization in terms of masses and springs provides a natural model for chemical bonds. We derive the classical equations of motion in detail for the three-particle chain. We then introduce two simple methods for numerically integrating the equations of motion, one based on Euler's method for differential equations, and the other a more accurate algorithm developed by Verlet. We analyze the dynamics of the three-particle system in terms of its normal modes of vibration. Finally, exploiting the closed-form solution admitted by the Hooke's law po.
Design and Implementation of a Damage Assessment System for Large-Scale Surface Warships Based on Deep Learning

Artificial intelligence technology and image recognition technology are playing an increasingly important role in information warfare, while battlefield image recognition and information processing are at the heart of information processing in warfare. This research will use deep learning image recognition technology and QT development platform, combined with target damage tree analysis and Bayesian network inference method, to research and develop the design of large-scale surface warships damage assessment system. A large-scale surface warships damage assessment system was designed. The system can quickly identify the target large-scale surface warships type with an accuracy rate of over 91%. On this basis, damage assessment is carried out in terms of target vulnerability, combatant power analysis, and bullet-eye rendezvous. A new damage classification is established. The system can improve the efficiency of large-scale surface warships damage assessment, can be well combined with the front-line information collection pictures to assess, and overcome the traditional large-scale surface warships damage assessment and problems of slow and inaccurate manual processing of raw data. It provides a new way of thinking for large-scale surface warships damage assessment research.
Ab initio study of foreign interstitial atom (C, N) interactions with intrinsic point defects in α-Fe

The behavior of carbon and nitrogen atoms in iron based solid solution is studied by ab initio densityfunctional-theory calculations. The interaction o faCo r aN atom in a-Fe with a vacancy, other C or N interstitials as well as self-interstitial atoms is discussed and compared to known experimental results. The migration of these two foreign interstitial atoms is determined in pure Fe or when a vacancy is present in the supercell. According to our results, there is a strong binding energy of C or N with vacancies, whereas a repulsion is observed with self-interstitial atoms. Furthermore, a vacancy can trap up to two C, and a covalent bonding forms between the two C atoms. The situation is not as clear for N atoms, and a competition between the formation of N-V pairs and NN-V triplets is very probable.
An automatic musical frequency detection and MIDI control system for brass instruments

Fundamental frequency detection algorithms optimized for use with instruments in the brass instrument family are presented. A new frequency tracking scheme based on adaptive periodic prediction is presented, and it is shown that this algorithm is equivalent to a high‐precision adaptive comb filter. Frequency detection schemes that do not take into account the unique spectral and acoustical properties of a particular instrument family usually generate errors of three types: (1) octave and harmonic detection errors, (2) half‐step errors that jitter rapidly about the true estimate, and (3) latency of detection. A frequency detection and live MIDI control system has been constructed for the trumpet, which significantly reduces detection errors and latency. By limiting the search range to the natural playing range of the trumpet, sampling rate and computation can be optimized, reducing latency in the estimates. By measuring and utilizing valve position in the frequency detection algorithm, the half‐step jitter.
Normalized Numerical Solutions for Rayleigh's Frequency Equation

In this paper, limiting forms of a transcedental‐frequency equation, attributed originally to Lord Rayleigh, are derived. The limiting forms are examined and their roots are used to find the exact normalized roots the original equation in the complex plane. A comprehensive collection of roots, considerably more extensive than that currently available, is tabulated for a range of normalized frequency.
Group Structure of Elliptic Curves over Finite Fields

Abstract Let A be a finite abelian group such that there is an elliptic curve defined over a finite field F q with E( F q)≅A. We will determine the possible group structures E( F qk) as E varies over all elliptic curves defined over F q with E( F q)≅A.
On global embedding

A basis vector treatment of tensor calculus in an N ‐dimensional (pseudo‐) Euclidean space is used to obtain new insights into the geometrical properties of curved Riemannian spaces of smaller dimension which are globally embedded in the N ‐space. In particular, it is shown that, in general for a globally embedded hypersurface, (i) partial derivatives of internal basis vectors with respect to internal coordinates must in general be expressed as a linear combination of external as well as internal basis vectors, (ii) there exist two different geometrical expressions, always equal in value, for the intrinsic curvature tensor, (iii) the geodesic equation contains more terms than does the usual one; the extra terms vanish for Schwarzschild metric embeddings. These points are illustrated by the example of a 2‐sphere embedded in Euclidean 3‐space.