Miracle-dz/UniFAR-FTUs huggingface dataset:
A stabilized Smoothed Particle Hydrodynamics, Taylor–Galerkin algorithm for soil dynamics problems

Modelling of failure under dynamic conditions in geomaterials with finite elements presents a series of complex problems, among which we can mention those of (i) volumetric locking, which results on higher failure loads, (ii) influence of mesh alignment, resulting to unrealistic failure surfaces, (iii) diffusion of the shear band over some element widths, (iv) nonoptimal propagation properties (numerical diffusion and dispersion), (v) fulfilling Babuska–Brezzi conditions when using the same order of interpolation for displacement and pressures in coupled problems and (vi) large deformation analysis.
Smallest Singular Value for Perturbations of Random Permutation Matrices

We take a first small step to extend the validity of Rudelson-Vershynin type estimates to some sparse random matrices, here random permutation matrices. We give lower (and upper) bounds on the smallest singular value of a large random matrix D+M where M is a random permutation matrix, sampled uniformly, and D is diagonal. When D is itself random with i.i. d terms on the diagonal, we obtain a Rudelson-Vershynin type estimate, using the classical theory of random walks with negative drift.
AN UPDATE OF QUANTUM COHOMOLOGY OF HOMOGENEOUS VARIETIES

We describe recent progress on QH� (G/P) with special emphasis of our own work. How many intersection points are there for two given lines in a plane? How many lines pass through two given points in a plane? It is the main concern in enumerative geometry to find solutions to such questions of counting numbers of geometric objects that satisfy certain geometric conditions. There are two issues here. First, we should impose conditions so that the expected solution to a counting problem is a finite number. Second, we will work in the complex projective space, so that Schubert's principle of conservation of number holds. Then we ask for this invariant. For instance to either of the aforementioned questions, the solution is a constant number 1, if the condition is imposed precisely as "two distinct given lines (resp. points) in a complex projective plane P 2 ".
Large-scale structures in random graphs

In recent years there has been much progress in graph theory on questions of the following type. What is the threshold for a certain large substructure to appear in a random graph? When does a random graph contain all structures from a given family? And when does it contain them so robustly that even an adversary who is allowed to perturb the graph cannot destroy all of them? I will survey this progress, and highlight the vital role played by some newly developed methods, such as the sparse regularity method, the absorbing method, and the container method. I will also mention many open questions that remain in this area.
Room Temperature Layer by Layer Growth of GaN on Atomically Flat ZnO

We have grown GaN on atomically flat ZnO (000-1) substrates at room temperature with pulsed laser deposition (PLD). We have found that atomically flat surfaces of ZnO (000-1) substrates with a clear step and terrace structure have been obtained by annealing in a box made of ceramic ZnO. We have also found that GaN grows epitaxially even at room temperature on the step and terrace ZnO surface. Reflection high energy electron diffraction (RHEED) observations have revealed that the GaN film grows in the layer by layer mode from the early stage of the film growth. X-ray reflectivity measurements have revealed that the heterointerface between GaN and ZnO is quite abrupt and its roughness is less than 0.5 nm.
Band structure calculations of photonic crystals with dispersive materials

The band structures of dispersive photonic crystals are numerically investigated. Based on the fmite-difference time-domain (FDTD) method with some auxiliary variables, time-stepping formulas are derived to compute the evolution of electromagnetic fields. The photomc crystals made of dispersive materials can be described either by the Lorentzian model or by the Drude model. In this paper, we describe how to use the time domain technique to calculate the dispersion relation of photonic crystals and then introduce the recursive convolution scheme to treat the photonic crystals with frequency-dependent materials. Band structures of photomc crystals without dispersion are calculated with the conventional FDTD time-stepping formulas and those with Lorentzian type dispersion and Drude type dispersion are also calculated with the recursive convolution scheme.
Two models for the spatially covariant field scattered by randomly rough pressure‐release surfaces with Gaussian spectra

Two models for the spatial covariance of scalar waves scattered by randomly rough pressure‐release surfaces are presented. The first model is based on partial integration of the Helmholtz–Kirchhoff integral. The second employs potential theory to solve the radiation problem from a surface that is thought of as a dipole source distribution. In‐plane and out‐of‐plane intensity and coherence from both models are compared using flat surfaces and surfaces with a Gaussian spectrum. Comparisons of intensity show good agreement if the surface is very rough and/or the direction is specular, and that for directions far from the specular one the second model is more accurate. Comparisons of coherence, on the other hand, show good agreement under all circumstances.
Microfluidic design and fabrication of wafer-scale varifocal liquid lens

Microfluidic design and fabrication was developed for wafer-scale varifocal liquid lens which is slim less than 0.9mm. The liquid-filled varifocal lens has advanced functions such as auto macro and focusing to obtain a high quality of image. This varifocal lens is similar to human eye and it consists of main Si frame which has penetrated inner hole, upside-bonded PDMS (polydimethylsiloxane) elastomer membrane, downside-bonded glass plate and optical fluid confined by these structures. Si frame, which has a circular hole for tunable lens chamber, several holes for actuator chamber and micro-fluidic channels between chambers, is fabricated using thin Si wafer and microelectromechanical system (MEMS) processes. When optical fluid is filled the internal cavity by conventional injection, void trapping which degrades optical performance or filling impossibility happens because of high aspect ratio between lens diameter and thickness for slim liquid lens. To prevent these problems, we developed wafer-based microfabrications of seal line dispensing, accurate dropping of optical fluid, pressing & bonding process in vacuum and UV sealant curing. Afterward, electro-active polymer actuators, which push the optical fluid to change the lens shape, was attached on the PDMS membrane of liquid lens wafer and sawing process of 9.4mm*9.0mm chip size followed. Finally, the varifocal liquid lens which is slim less than 0.6mm thickness (0.9mm included actuators), tunable more than 20diopter changes of refractive power, guaranteed reliability of 300,000 repetitions and suitable for mass production, was realized.
On a gateway between the Laguerre process and dynamics on partitions

Probability measures and stochastic dynamics on matrices and on partitions are related by standard, albeit technical, discrete to continuous scaling limits. In this paper we provide exact relations, that go in both directions, between the eigenvalues of the Laguerre process and certain distinguished dynamics on partitions. This is done by generalizing to the multidimensional setting recent results of Miclo and Patie on linear one-dimensional diffusions and birth and death chains. As a corollary, we obtain an exact relation between the Laguerre and Meixner ensembles. Finally, we explain the deep connections with the Young bouquet and the z-measures on partitions.
A rigidity theorem for Haken manifolds

A compact, orientable 3-manifold M is called hyperbolic if int M admits a complete hyperbolic structure (Riemannian metric of constant curvature − 1) of finite volume. Any hyperbolic 3-manifold M is irreducible, and each component of ∂M is an incompressible torus. Let f: M → N be a proper, continuous map between hyperbolic 3-manifolds. By Mostow's Rigidity Theorem [8], if f is π1-isomorphic then f is properly homotopic to a diffeomorphism g: M → N such that g | int M: int M → int N is isometric. In particular, the topological type of int M determines uniquely the hyperbolic structure on int M up to isometry, so the volume vol (int M) of int M is well-defined. This Rigidity Theorem is generalized by Thurston[11, theorem 6·4] so that any proper, continuous map f:M → N between hyperbolic 3-manifolds with vol(int M) = deg(f) vol(int N) is properly homotopic to a deg(f)-fold covering g:M → N such that g | int M: int M → int N is locally isometric.
High efficiency polycrystalline silicon solar cells using phosphorus pretreatment

Recent improvements in crystalline silicon solar cell energy conversion efficiency to beyond 20% have been obtained by combining surface oxide passivation with high quality, low resistivity substrates. The objective of the present work was to evaluate the effectiveness of these techniques in improving efficiency on lower quality cast polycrystalline silicon. Due to the poorer crystallographic quality and higher levels of secondary impurities, an additional phosphorus pretreatment was found to reliably improve the performance of the polycrystalline cells above those fabricated without this pretreatment. Cell energy conversion efficiencies were notably higher than previously reported for the present material with values in the 15.3–16.0% range obtained for p‐type substrates of 0.1–1 Ω cm resistivity.
Further VLBA observations of Sio masers toward Mira variable stars

We present the results of continued monitoring of the SiO masers at 7 mm wavelength in several of the Mira variable stars reported in Cotton et al. (2004, A&A, 414, 275) (o Ceti = Mira, U Orionis = U Ori, R Aquarii = R Aqr) over a period of 16 months, extending the observations to several pulsation cycles. The observed size of the maser rings varied by 3–14% with time but show no clear correlation with pulsation phase. In all cases, the SiO masers appear just outside the dense molecular layer indicated by near-IR observations. Rotation (or large scale motion) is possibly detected in o Ceti with a period of 89 × sin(i) years. We find linear polarization up to ∼60% and at several epochs predominantly tangentially ordered polarization vectors indicate a radial magnetic field direction. Jet-like features are examined in o Ceti and R Aqr and in both cases, the magnetic field appears elongated with the masing structure. This suggests that the dynamic feature in the envelope is dragging the magnetic field or that the gas is constrained to follow magnetic field.
Semiclassical Sampling and Discretization of Certain Linear Inverse Problems

We study sampling of Fourier Integral Operators $A$ at rates $sh$ with $s$ fixed and $h$ a small parameter. We show that the Nyquist sampling limit of $Af$ and $f$ are related by the canonical relation of $A$ using semiclassical analysis. We apply this analysis to the Radon transform in the parallel and the fan-beam coordinates. We explain and illustrate the optimal sampling rates for $Af$, the aliasing artifacts, and the effect of averaging (blurring) the data $Af$. We prove a Weyl type of estimate on the minimal number of sampling points to recover $f$ stably in terms of the volume of its semiclassical wave front set.
Techniques of aligning carbon nanotubes

This paper reviews major techniques of aligning carbon nanotubes, either during the growth or by the post-growth processing. A number of post-processing alignment techniques are discussed, which employ mechanical stretching, fracture, compression, friction, filtration, fiber drawing, gas flow, liquid crystals, Langmuir-Blodgett technique, acoustic, magnetic and electric fields. The suitability of those techniques to industrial applications is analyzed.
Multiple Time Series Regression with Integrated Processes

This paper develops a general asymptotic theory of regression for processes which are integrated of order one. The theory includes vector autoregressions and multivariate regressions amongst integrated processes that are driven by innovation sequences which allow for a wide class of weak dependence and heterogeneity. The models studied cover cointegrated systems and quite general linear simultaneous equations systems with contemporaneous regressor-error correlation and serially correlated errors. Problems of statistical testing in vector autoregressions and multivariate regressions with integrated processes are also studied. It is shown that the asymptotic theory for conventional tests involves major departures from classical theory and raises new and important issues of the presence of nuisance parameters in the limiting distribution theory.
Pressureless Euler alignment system with control

We study a non-local hydrodynamic system with control. First, we characterize the control dynamics as a sub-optimal approximation to the optimal control problem constrained to the evolution of the pressureless Euler alignment system. We then discuss the critical thresholds that lead to global regularity or finite-time blow-up of strong solutions in one and two dimensions. Finally, we use a finite volume scheme, coupled with an implicit–explicit time integrator to solve numerically the stiff scale of the controlled system. Several numerical simulations are shown to validate the theoretical and computational results of the paper.
Dynamical Mordell-Lang and Automorphisms of Blow-ups

We show that if $\phi : X \to X$ is an automorphism of a smooth projective variety and $D \subset X$ is an irreducible divisor for which the set of $d$ in $D$ with $\phi^n(d)$ in $D$ for some nonzero $n$ is not Zariski dense, then $(X, \phi)$ admits an equivariant rational fibration to a curve. As a consequence, we show that certain blowups (e.g. blowups in high codimension) do not alter the finiteness of $\textrm{Aut}(X)$, extending results of Bayraktar-Cantat. We also generalize results of Arnol'd on the growth of multiplicities of the intersection of a variety with the iterates of some other variety under an automorphism. These results follow from a non-reduced analogue of the dynamical Mordell-Lang conjecture. Namely, let $\phi : X \to X$ be an \'etale endomorphism of a smooth projective variety $X$ over a field $k$ of characteristic zero. We show that if $Y$ and $Z$ are two closed subschemes of $X$, then the set $A_\phi(Y,Z) = \{n : \phi^n(Y) \subseteq Z\}$ is the union of a finite set and finitely many residue classes, whose modulus is bounded in terms of the geometry of $Y$.
1 1 m 6 A modification of U 6 snRNA modulates 2 usage of two major classes of pre-mRNA 5 ’ 3 splice site 4 5

20 Alternative splicing of messenger RNAs is associated with the evolution of developmentally complex 21 eukaryotes. Splicing is mediated by the spliceosome, and docking of the pre-mRNA 5’ splice site into 22 the spliceosome active site depends upon pairing with the conserved ACAGA sequence of U6 snRNA. 23 In some species, including humans, the central adenosine of the ACAGA box is modified by N 24 methylation, but the role of this mA modification is poorly understood. Here we show that mA 25 modified U6 snRNA determines the accuracy and efficiency of splicing. We reveal that the conserved 26 methyltransferase, FIO1, is required for Arabidopsis U6 snRNA mA modification. Arabidopsis fio1 27 mutants show disrupted patterns of splicing that can be explained by the sequence composition of 5’ 28 splice sites and cooperative roles for U5 and U6 snRNA in splice site selection. U6 snRNA mA 29 influences 3’ splice site usage. We generalise these findings to reveal two major classes of 5’ splice 30 site in diverse eukaryotes, which display anti-correlated interaction potential with U5 snRNA loop 1 31 and the U6 snRNA ACAGA box. We conclude that U6 snRNA mA modification contributes to the 32 selection of degenerate 5’ splice sites crucial to alternative splicing. 33 34 35
On the infinite divisbility of the Pareto distribution

Summary That the Pareto distribution is infinitely divisible is a simple consequence of an important theorem by Goldie and Steutel if an observation by Thyrion is used. In the present paper the author investigates the Pareto distribution more closely and proves that it belongs to a well-known subclass of the class of infinitely divisible distributions, the so called class L. That is achieved by showing that the Pareto distribution can be viewed as a “generalized Γ-convolution”. The corresponding problem concerning the lognormal distribution is briefly touched upon.
A high-order finite difference investigation of boundary layer perturbations

We present a new numerical treatment of the vorticity-velocity form of the governing equations of fluid motion, based on the application of compact finite differences. The mathematical formulation of these equations is discussed, as are the techniques used to discretise them. The solver thus obtained is validated against analytical solutions to model problems, and against the more physical test case of developing Tollmien-Schlichting waves in a parallelised Blasius boundary layer. We then use this solver to examine a reduced-order model of streaks in a turbulent boundary layer. The properties of the streaks produced by the solver are discussed, with a particular focus on the means of their generation. Following this, we examine the use of spanwise oscillation of the wall, which is known to reduce drag in turbulent boundary layers. The parameters of the oscillation (specifi­ cally its magnitude, its frequency and the phase difference between the wall motion and the streak forcing) are altered and their influence on streak development investigated. It is found that in certain cases, the modification to the basis flow by wall oscillation means that the perturbations can grow exponentially. We also investigate the effects of altering the pattern of oscillation from sinusoidal in time to a smoothed square wave or sawtooth wave. Finally, the results are reviewed and conclusions drawn, and possible extensions to the research presented in the thesis are suggested.
Distributed demand-side contingency-service provisioning while minimizing consumer disutility through local frequency measurements and inter-load communication

We consider the problem of smart and flexible loads providing contingency reserves to the electric grid and provide a Distributed Gradient Projection (DGP) algorithm to minimize loads' disutility while providing contingency services. Each load uses locally obtained grid-frequency measurements and inter-load communication to coordinate their actions, and the privacy of each load is preserved: only gradient information is exchanged---not disutility or consumption information. We provide a proof of convergence of the proposed DGP algorithm, and we compare its performance through simulations to that of a "dual algorithm" previously proposed in the literature that solved the dual optimization problem. The DGP algorithm solves the primal problem. Its main advantage over the dual algorithm is that it is applicable to convex---but not necessarily strictly convex---consumer disutility functions, such as a model of consumer behavior that is insensitive to small changes in consumption, while the dual algorithm is not. Simulations show the DGP algorithm aids in arresting grid-frequency deviations in response to contingency events and performs better or similarly to the dual algorithm in cases where the two can be compared.
On the classification of asymptotic quasinormal frequencies for $d$-dimensional black holes and quantum gravity

We provide a complete classification of asymptotic quasinormal frequencies for static, spherically symmetric black hole spacetimes in d dimensions. This includes all possible types of gravitational perturbations (tensor, vector and scalar type) as described by the Ishibashi–Kodama master equations. The frequencies for Schwarzschild are dimension independent, while for Reissner–Nordstrom are dimension dependent (the extremal Reissner–Nordstrom case must be considered separately from the non–extremal case). For Schwarzschild de Sitter, there is a dimension independent formula for the frequencies, except in dimension d = 5 where the formula is different. For Reissner–Nordstrom de Sitter there is a dimension dependent formula for the frequencies, except in dimension d = 5 where the formula is different. Schwarzschild and Reissner–Nordstrom Anti–de Sitter black hole spacetimes are simpler: the formulae for the frequencies will depend upon a parameter related to the tortoise coordinate at spatial infinity, and scalar type perturbations in dimension d = 5 lead to a continuous spectrum for the quasinormal frequencies. We also address non–black hole spacetimes, such as pure de Sitter spacetime—where there are quasinormal modes only in odd dimensions—and pure Anti–de Sitter spacetime—where again scalar type perturbations in dimension d = 5 lead to a continuous spectrum for the normal frequencies. Our results match previous numerical calculations with great accuracy. Asymptotic quasinormal frequencies have also been applied in the framework of quantum gravity for black holes. Our results show that it is only in the simple Schwarzschild case which is possible to obtain sensible results concerning area quantization or loop quantum gravity. In an effort to keep this paper self–contained we also review earlier results in the literature.
A recursively feasible and convergent Sequential Convex Programming procedure to solve non-convex problems with linear equality constraints

A computationally efficient method to solve non-convex programming problems with linear equality constraints is presented. The proposed method is based on a recursively feasible and descending sequential convex programming procedure proven to converge to a locally optimal solution. Assuming that the first convex problem in the sequence is feasible, these properties are obtained by convexifying the non-convex cost and inequality constraints with inner-convex approximations. Additionally, a computationally efficient method is introduced to obtain inner-convex approximations based on Taylor series expansions. These Taylor-based inner-convex approximations provide the overall algorithm with a quadratic rate of convergence. The proposed method is capable of solving problems of practical interest in real-time. This is illustrated with a numerical simulation of an aerial vehicle trajectory optimization problem on commercial-of-the-shelf embedded computers.
A Lyapunov‐type theorem from Kadison–Singer

Marcus, Spielman, and Srivastava [‘Interlacing families II: mixed characteristic polynomials and the Kadison–Singer problem’, Preprint, 2013, arXiv:1306.3969] recently solved the Kadison–Singer problem by showing that if u1,…,um are column vectors in Cd such that ∑uiui∗=I , then a set of indices S⊆{1,…,m} can be chosen so that ∑i∈Suiui∗ is approximately 12I , with the approximation good in operator norm to order ϵ1/2 where ϵ=max∥ui∥2 . We extend their result to show that every linear combination of the matrices uiui∗ with coefficients in [0,1] can be approximated in operator norm to order ϵ1/8 by a matrix of the form ∑i∈Suiui∗ .