Miracle-dz/UniFAR-FTUs huggingface dataset:
The propagation of VLF wave in layered earth-ionosphere waveguide

In this paper, propagation of VLF wave in a layered ground model in spherical coordinate system is treated analytically. Because of the fact that the electrical parameters are not uniform, the ground is regarded as a stratified homogeneous dielectric layer. Especially in the far field of the earth-ionosphere waveguide the effects by the anisotropic magnetic field are considered. Finally, some new numerical results and discussions about the far fields are given.
Modelling of bubbly flows using volume of fluid, front tracking and discrete bubble models

Intense contact between gasses and liquids is an essential step in many (bio) chemical and metallurgic processes amongst others. A device that is often used for this step of the process is the bubble column. Bubble columns have good mixing characteristics, resulting in good mass and heat transfer qualities. In spite of their frequent application, fundamental knowledge on the behaviour of bubble columns is still lacking. Their design and operation is based on a large number of empirical correlations and scale-up continues to be very complicated. In this thesis, a number of mathematical models have been developed, improved and validated which can help obtain more detailed knowledge on the important phenomena prevailing in gas-liquid dispersed flows.
Low Froude Number Flow Past Three-Dimensional Obstacles. Part II: Upwind Flow Reversal Zone

Abstract The present paper contains a continuation of our study of the flow of a density-stratified fluid past three-dimensional obstacles for Froude number ∼O(1). Linear theory (large Froude number) and potential-flow-type theory (small Froude number) are both invalid in this range, which is of particular relevance to natural, atmospheric flows past large mesoscale mountains. The present study was conceived to provide a systematic investigation of the basic aspects of this flow. Thus, we have excluded the effects of friction, rotation, nonuniform ambient flow, and the complexity of realistic terrain. In Part I of this study we focused on the pair of vertically oriented vortices forming on the lee side when the Froude number decreases below 0.5 (approximately), and argued that their formation may be understood in terms of nonlinear aspects of inviscid gravity waves, i.e., without invoking traditional arguments on the separation of the friction boundary layer. Herein we examine the zone of flow reversal on.
Turbulent inflow boundary conditions for LES

Methods of generating turbulent in ow boundary conditions for LES and DNS are surveyed and ranked according to their e ectiveness. Methods included in the survey are random number pseudo turbulence, rescaling of isotropic turbulence data in space and/or time, Taylor's hypothesis applied to a frozen three-dimensional turbulent velocity eld, and the direct transfer of turbulent velocity data from an auxiliary simulation. The simpler approaches are shown to be acceptable for ows with strong inviscid instabilities such as distorted isotropic turbulence or turbulent wakes. These same approaches are found to fail in wall-bounded ows where weak viscous instabilities prevail. Wall-bounded ows appear to require the more sophisticated methods, which are largely based on the direct transfer of accuratelysimulated turbulent data. E cient means of generating such data are also surveyed. Very simple time-dependent, simulation-based in ow generation procedures such as a parallelow boundary layer are shown to yield a quantum leap in accuracy over the simpler methods, including those that apply Taylor's hypothesis to a accurately-simulated frozen velocity eld. While the parallelow boundary layer method is adequate in many cases, greater accuracy can be achieved if necessary by accounting for spatial growth e ects via Spalart's original method, or by more recent variants. These rather sophisticated methods are still cost e ective and can also account for the e ects of pressure gradients.
Mathematical Modeling: A Bridge to STEM Education

The purpose of this study is making a theoretical discussion on the relationship between mathematical modeling and integrated STEM education. First of all, STEM education perspective and the construct of mathematical modeling in mathematics education is introduced. A review of literature is provided on how mathematical modeling literature may contribute to theoretical conceptualization of STEM education by specifically addressing the professional competencies that teachers need. The discussion followed on how mathematical modeling activities and project-based learning contexts contribute to integrated STEM education by providing two research-based experiences, one of which is the model rocketry project carried out by pre-service physics teachers and the other one of which is a mathematical modeling activity solved by pre-service mathematics teachers.
Effects of Sample Size in Classifier

This paper discusses the effect of finite sample size on pa- rameter estimates and their subsequent use in functions. General and parameter-specific expressions for the expected bias and variance of the functions are derived. These expressions are then applied to the Bhattacharyya distance and the analysis of the linear and quadratic classifiers, providing valuable insight into the relationship between the number of features and the number of training samples. Also, because of the functional form of the expressions, we present an empirical ap- proach which will enable asymptotic performance to be accurately es- timated using a very small number of samples. Results are experimen- tally verified using artificial data in controlled cases and using real, high-dimensional data.
SIW based compact and dual-band equilateral triangular antennas

Abstract In this paper, a substrate integrated waveguide (SIW)-based equilateral compact and dual band triangular antennas have been proposed. A SIW-based coaxial fed equilateral triangular antenna has been initially considered. The antenna is found to resonate at 5.28 GHz corresponding to U-NII-2 WLAN band. Two sides of the said antenna are made perfect electrical conductor wall with array of metallic vias and the third side is kept open which acts like a perfect magnetic conductor (PMC) wall. A single slit has been introduced on the PMC wall of the initial antenna which causes a decrease in resonating frequency from 5.28 to 4.29 GHz. The antenna has been further miniaturized by introducing another parallel extra slit on the PMC wall which leads to a decrease in the resonating frequency to 3.3 GHz. The former antenna with single slit is found to exhibit 33% miniaturization while the latter with double slits reflects 56% miniaturization. By changing the coaxial feed location of the initial antenna at off-axis position, a dual band antenna has been realized. The dual band antenna is found to excite both TE101 and TE202 modes efficiently with corresponding resonating frequencies at 4.18 and 8.85 GHz. The prototypes have been fabricated on Arlon AD270 substrate and simulated results are compared with the measured ones. A good agreement has been observed between the simulated and measured results.
Fourier-finite element analysis of temperature fields in space structures

Space structures consisting of thin walled beams are subjected to incident solar heat flux and emit thermal energy by radiation. This thermal analysis considers the nonlinear and time dependent heat conduction in complex structures. A Fourier finite element thermal analysis method for a circular tube is presented. The structure is modelled using the finite element method in the longitudinal direction and by Fourier series in the circumferential direction. Each node in the circle tube elements possesses three degrees of freedom: the average temperature and the amplitudes of the cos and sine shaped perturbation temperatures. The changes of the average temperature and the perturbation temperatures are decoupled in each time step. Therefore, the solution can be obtained in each time step by solving a set of nonlinear equations for the average temperature, then the average temperature is used to solve two sets of linear equations for the cos and sine shaped perturbation temperatures. The present method was used to calculate the time dependent temperature fields for the solar array of the Hubble space telescope. A thermal effect could cause twisting of the solar array.
FIR Filters for Linear Continuous-Time

In this letter, we propose a new filter (HF) with a finite impulse response (FIR) structure for linear continuous-time state-space systems. This filter is called the FIR filter (HFF). The upper bound for an performance criterion is derived and then minimized among the filters with linearity, FIR structure, and quasideadbeat property. The HFF is obtained by solving the dif- ferential Riccati equation. We show through simulations that the HFF is more robust against temporary uncertainties and is faster in convergence than a conventional HF. Index Terms—Finite impulse response (FIR) structure, filter (HF), quasideadbeat property, state estimation.
Modelling yeast cell growth using stochastic branching processes

This paper aims to demonstrate that the general Crump–Mode–Jagers branching process may be used in a natural way to model the asymmetric growth of budding yeast cells. The models obtained are generalisations of the deterministic model proposed by Hartwell and Unger (1977): all the results that are derived in that paper may be obtained using branching-process methods, but such methods also apply when account is taken of the biologically obvious fact that the various phases of the cell growth are of random rather than fixed duration. In their full generality, branching processes involve more parameters than can be estimated by experiment, but we present below a special case in which this problem is not likely to arise. A recent paper, Lord and Wheals (1980), discusses more of the biological background than is appropriate here. In the present paper, we show how certain statistical procedures for our model may be developed.
Past, Present and Future of Chinese Astronomy

Abstract Through out the ancient history, Chinese astronomers had made tremendous achievements. Since the main purpose of the ancient Chinese astronomy was to study the correlation between man and the universe, all the Emperors made ancient Chinese astronomy the highly regarded science throughout the history. After a brief introduction of the achievement of ancient Chinese astronomy, I describe the beginnings of modern astronomy research in China in the 20th century. Benefiting from the fast development of Chinese economy, the research in astronomy in China has made remarkable progress in recent years. The number of astronomers has doubled in the past ten years, and the number of graduate students has grown over 1300. The current budget for astronomy research is ten times larger than that ten years ago. The research covers all fields in astronomy, from galaxies to the Sun. The recent progress in both the instruments, such as the Guo Shoujing's telescope, a Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), and the theoretical research will be briefly presented. The ongoing and future projects on the space- and ground-based facilities will be described, including the Five Hundred Meter Aperture Spherical Radio Telescope (FAST), “Chang E” (Lunar mission) project, Hard X-ray Modulate Telescope (HXMT), DArk Matter Particle Explorer (DAMPE), Deep Space Solar Observatory (DSO), Chinese Antarctic Observatory (CAO), 65m steerable radio telescope, Chinese Spectral Radioheliogaph (CSRH) etc.
Progress in the realization of the PRIMA neutral beam test facility

The ITER project requires additional heating by two neutral beam injectors, each accelerating to 1 MV a 40 A beam of negative deuterium ions, to deliver to the plasma a power of about 17 MW for one hour. As these requirements have never been experimentally met, it was recognized as necessary to setup a test facility, PRIMA (Padova Research on ITER Megavolt Accelerator), in Italy, including a full-size negative ion source, SPIDER, and a prototype of the whole ITER injector, MITICA, aiming to develop the heating injectors to be installed in ITER. This realization is made with the main contribution of the European Union, through the Joint Undertaking for ITER (F4E), the ITER Organization and Consorzio RFX which hosts the Test Facility. The Japanese and the Indian ITER Domestic Agencies (JADA and INDA) participate in the PRIMA enterprise; European laboratories, such as IPP-Garching, KIT-Karlsruhe, CCFE-Culham, CEA-Cadarache and others are also cooperating. Presently, the assembly of SPIDER is on-going and the MITICA design is being completed. The paper gives a general overview of the test facility and of the status of development of the MITICA and SPIDER main components at this important stage of the overall development; then it focuses on the latest and most critical issues, regarding both physics and technology, describing the identified solutions.
Robust verification for image feature matching based on RANSAC

Error matching points usually lead to an inaccurate transformation from images into poor image registrations.In this paper,a method for verifying accurate matching features was proposed based on random sample consensus(RANSAC),and a robust algorithm for estimating geometric transform matrix between images was presented.Firstly,initial matching features were obtained from the similarity of feature vectors,and then weights could be gained from the gray information around each feature point.In the process of iterative fitting geometric transform matrix using RANSAC,error matches were eliminated by minimization cost function.Finally,precise image registration was achieved.Experimental results show that the algorithm has good noise robustness and ideal image registration.
Diffraction patterns from multiple tilted laser apertures: numerical analysis

We propose a Rayleigh-Sommerfeld based method for numerical calculation of multiple tilted apertures near and far field diffraction patterns. Method is based on iterative procedure of fast Fourier transform based circular convolution of the initial field complex amplitudes distribution and impulse response function modified in order to account aperture and observation planes mutual tilt. The method is computationally efficient and has good accordance with the results of experimental diffraction patterns and can be applied for analysis of spatial noises occurring in master oscillator power amplifier laser systems. The example of diffraction simulation for a Phobos-Ground laser rangefinder amplifier is demonstrated.
SOME REMARKS ON SPLINES

Although detailed proofs of certain of the more elegant fundamental properties of splines are sometimes non-trivial, the basic underlying ideas are very simple indeed. With a modern computer it is easy to implement the methods described in this paper. Many computer libraries will include optimisation and spline subroutines which can be combined conveniently for this purpose. (For example, several of the calculations in this paper were carried out with the aid of NAG library facilities.)
A Simplified Method of Moment (MoM) Approach to solving nth Order Linear Differential Equations

The Method of Moment (MoM) is a very successful tool in solving complex geometry electromagnetic (EM) problems, and is considered as the first computational approach in solving these problems. This paper approaches MoM in a very simple way and aims to produce a valuable procedure to solving boundary value problems, especially nth differential equations. Starting with the definition of the method, the problem is converted into its respective integral equation form, and then the unknown function is expanded into a sum of weighted basis functions, where the weight coefficients are to be found. The Galerkin method, which selects testing functions equal to the basic functions, is adopted. The problem then becomes a system of linear equations, which is solved analytically or numerically to find the needed weight coefficients. Two examples, a second- and a third-order differential equations, are considered to illustrate the application of the procedure, which can be used as well for the solution of other boundary-value problems. The considered examples show the detailed calculation process and make it easier to understand the solution procedure.
Reaearch into The Algorithm of False Points Elimination in Three-station Cross Location

Aiming at the problem that the passive direction finding cross location will generate false points under the condition of multi-target emitter,this paper puts forward an improved algorithm to eliminate false points by three-station cross location.Firstly,this paper calculates out the cross point of two-station direction finding,then detects the association matching to determine the right association according to the measurement result of the third station.The simulative result shows that the accuracy rate of the method is superior than the method that directly using three stations to measure data for association,and the calculation quantity decreases obviously,can eliminate the false points fast and effectively.
Notes on random chords in convex bodies

Consider a compact body E embedded in a convex compact body G. A point P is randomly chosen in E and three different rays to the boundary ∂G of G are generated by P. Ray is in a uniformly random direction and has length R, ray is through a second random point chosen from within G and has length W, and ray is to a random point in ∂G and has length Y. The distribution of Y is obtained and is related to previous work. When E is specialized to G or to ∂G, other known results are retrieved. The paper ends with a discussion of a conjecture relating the means of R, W and Y.
A FLEXIBLE RELATIONAL FEATURE MODEL FOR FALL DETECTION

Vision based fall detection solutions support elderly who live alone in their homes. For people falling down and not being able to stand up on their own again, such a fall is a major risk. In this work, we show a person detection approach using a relational feature model using consumer depth cameras. We propose a flexible relational feature model (FRFM) for fall detection in combination with histogram similarity functions such as the bhattacharyya distance, histogram intersection, histogram correlation and the chi-square 2 histogram similarity function. FRFM is an extension of the relational feature model (RFM) with the advantage that it can be used for all rotations of a body. The extension is necessary for fall detection due to the fact, that a lying person is rotated in the image where the standard person detection approach detects upright standing persons only. The relational features are computed for verification situations during fall detection on the basis of the Histograms of Oriented Gradients (HOG) feature descriptor. The experimental results show the best setup parameters for our feature model with different types of images (RGB and depth) and results on the specific field of fall detection.
Interplay between central ECRH and saturated (m, n)  =  (1, 1) MHD activity in mitigating tungsten accumulation at ASDEX Upgrade

The interplay between central electron cyclotron resonance heating (ECRH) and saturated (m, n) = (1, 1) magnetohydrodynamic (MHD) instabilities in mitigating central W accumulation at ASDEX Upgrade is analysed. The evolution of the intrinsic tungsten density in a typical ASDEX Upgrade H-mode discharge with central ECRH and saturated (1, 1) modes in-between sawtooth crashes is presented. The W density profile evaluated averaging over mode rotation and assuming axisymmetry are deeply hollow inside the q = 1 surface during mode saturation. In order to provide a mode-resolved picture, a new technique for the determination of 2D mode-resolved intrinsic W density maps in the presence of saturated MHD instabilities is developed. For the first time the full decoupling of the impurity density from electron density and temperature contributions to experimental 2D SXR tomographic reconstructions in the presence of saturated MHD activity can be performed. These mode-resolved 2D W density maps reveal that the impurity hole is located inside the displaced core of the saturated (1, 1) mode, while the W density inside the magnetic island is flat. Modelling the W density using the combined neoclassical and gyrokinetic codes NEO and GKW assuming axisymmetry and including the effects of toroidal rotation reproduces the poloidal asymmetries outside of the q = 1 surface correctly, but predicts centrally peaked W density profiles in the centre. This suggests that the hollowness inside the q = 1 surface is tied to the presence of the saturated (1, 1) mode.
Object Detection and Recognition Based on Color and Shape Features

A method of similar objects recognition in complex environment based on color and shape features is proposed. The distributing color space of certain object is obtained by learning-extending method in order to deal with the image captured under the varied lightness. Shape features of certain object with shadow on it or visualizing partly are detected by improved Hough transform. An object is fuzzy judged based on fusing its color belief and shape belief. The validity of this method is proved by the experiments on mobile robot.
A constitutive model for the uplift behavior of anchors in cohesionless soils

Abstract A series of triaxial tests has been performed to establish the stress‐strain curves for I‐Lan sand and Taipei silty sand. A constitutive model for the continuous strain hardening‐softening and volumetric dilatancy of these two soils is proposed, based on the results of triaxial tests. Using this model, a numerical program is then established, with FLAC software, to analyze the uplift behavior of model anchors in sand and field anchors in silty soil. It was found from triaxial tests, that the peak friction angle increases with relative density of soil and decreases with confining pressure. A non‐associated flow rule between plastic strain increment and stress tensor was found. As accumulative plastic strain, relative density and confining pressure were changed, the mobilized friction angle and mobilized dilatancy angle also changed. All parameters needed for the proposed model can be expressed as functions of relative density and confining pressure. This model can calculate the stress‐ strain curves of cohesionless soils determined from triaxial tests accurately. The load‐displacement behaviors determined from anchor tests are compared with those calculated from this numerical program, the numerical results are in good agreement with the test results not only for model anchors in sand but also for different types of field anchors in silty soil.
On a Class of Complete Simple Sets

Since the solution of Post' s Problem by Friedberg and Muchnik, a good deal of abstract knowledge about the semilattice of recursively enumerable degrees has been developed, especially in recent papers of G. E. Sacks. In this note, we show that one specific class of simple sets contains only sets of degree 0'; no contribution to the general theory is claimed. One of the sets belonging to the special class considered is the original simpie-but-not-hypersimple S of Post [1]. According to information received from Sacks, J. R. Myhill gave a proof, in 1953, of the completeness of S. However, as far as we know, Myhill' s proof (presented in a seminar) does not exist in published form.