Miracle-dz/UniFAR-FTUs huggingface dataset:
Efficient non‐linear model reduction via a least‐squares Petrov–Galerkin projection and compressive tensor approximations

A Petrov–Galerkin projection method is proposed for reducing the dimension of a discrete non‐linear static or dynamic computational model in view of enabling its processing in real time. The right reduced‐order basis is chosen to be invariant and is constructed using the Proper Orthogonal Decomposition method. The left reduced‐order basis is selected to minimize the two‐norm of the residual arising at each Newton iteration. Thus, this basis is iteration‐dependent, enables capturing of non‐linearities, and leads to the globally convergent Gauss–Newton method. To avoid the significant computational cost of assembling the reduced‐order operators, the residual and action of the Jacobian on the right reduced‐order basis are each approximated by the product of an invariant, large‐scale matrix, and an iteration‐dependent, smaller one. The invariant matrix is computed using a data compression procedure that meets proposed consistency requirements. The iteration‐dependent matrix is computed to enable the least‐squares reconstruction of some entries of the approximated quantities. The results obtained for the solution of a turbulent flow problem and several non‐linear structural dynamics problems highlight the merit of the proposed consistency requirements. They also demonstrate the potential of this method to significantly reduce the computational cost associated with high‐dimensional non‐linear models while retaining their accuracy. Copyright © 2010 John Wiley & Sons, Ltd.
Shock wave interaction with convex circular cylindrical surfaces

The reflection of shock waves off cylindrical surfaces of different radii is examined with the help of time-resolved flow visualization. The primary diagnostic is a newly developed technique based on the tracking of deliberately introduced small perturbations in the flow. The main focus of the investigation is to determine at which position the shock wave receives information about the shape of the wall that it reflects off. In the pseudo-steady shock reflection off a plane wall, it is commonly accepted that the reflection changes from regular to irregular as soon as sonic signals generated behind the reflection point catch up with the reflection point, and the common interpretation is that this corresponds to the transition from regular to Mach reflection (the so-called sonic criterion). The results obtained here for convex circular surfaces show that this ‘catch-up’ condition occurs at wall angles considerably higher than in the plane wall case, while a visible Mach stem occurs only further along the surface at wall angles distinctively lower than those for plane walls. Tests are also conducted on a surface where a cylindrical portion is followed by a fixed angle plane section. The Mach numbers are chosen to be on either side of the plane wall transition condition so as to examine the adjustment from reflection on the cylindrical portion to that on the plane wall. These tests confirm that the wall angle at which sonic ‘catch-up’ to the reflection point occurs on the cylindrical surface is much higher than the corresponding wall angle predicted by the sonic criterion for a plane wall. While the transition from regular to irregular reflection is not the main concern of this contribution, the present results show that the transition criteria developed for steady and pseudo-steady flows are only of limited use in the fully unsteady flows such as the one investigated here.
Application of two methods for N2O emission estimates to Bulgaria and the Netherlands.

Nitrous oxide (N 2 O) is one of the greenhouse gases in the earth's atmosphere. This study focuses on two methodologies for estimating N 2 O emissions at the national scales a method developed in the Netherlands (NEO method), and the IPCC Guidelines for National Greenhouse Gas Inventories (IPCC method). The purpose of this study is: (i) to apply both the IPCC and NEO methods to Bulgaria and the Netherlands, (ii) to investigate differences between the NEO and IPCC methods and (iii) to compare emissions from Bulgaria to emissions from the Netherlands. There are a number of differences between the NEO and IPCC methods. First, the NEO method includes more sources of N 2 O than the IPCC method. Second, some emissions are estimated in different ways. Due to these differences the IPCC method results in higher total emissions than the NEO method: for both countries IPCC emissions are about 20% higher than those of the NEO method (mid-point estimates). These differences result from a net effect; for some sources the IPCC method exceeds the NEO method (in particular for agriculture) and for others the IPCC estimates are lower. The sources not included in the IPCC method are natural emissions, enhanced background emissions from mineral soils, N 2 O induced by NO x deposition, chemical industries other than nitric and adipic acid production, atmospheric formation of N 2 O, use in anaesthesia, enhanced emissions due to global warming and aquatic emissions due to non-agricultural nitrogen inputs. NEO and IPCC estimates for N 2 O emissions from Bulgaria are 24 and 29 Gg N y -1 , respectively, and from the Netherlands 37 and 45 Gg N y -1 (mid-point estimates). Thus annual anthropogenic N 2 O emissions from the Netherlands are about 15 Gg N 2 O-N higher than those from Bulgaria. Dutch emissions exceed Bulgarian in particular for the following sources: agriculture, traffic and nitric acid production. These differences are caused by differences in human activities mainly.
On the Unit Groups of Commutative Modular Group Algebras of KT-Groups

Let G be an abelian group and let R be a commutative indecomposable p-perfect ring with identity of prime characteristic p. Denote by RG the group ring of G over R and by V(RG) the group of normalized units (i.e., the units of augmentation 1) of the group ring RG. Warfield [16] introduces the concept KT-module A over a discrete valuation ring R and invariants h(α, A) of this module for limit ordinals α. We compute the invariants h(α, V(RG)) of the group V(RG). Our result correct essential mistakes of the result in this direction of Danchev [4].
Flow in a channel with longitudinal ribs

The laminar, viscous flow between parallel plates with evenly spaced longitudinal ribs is solved by an eigenfunction expansion and point-match method. The ribs on both plates may by symmetrically placed or staggered. For a given pressure gradient, the mean velocity is plotted as a function of the geometric parameters. The authors find the wetted perimeter and the friction factor-Reynolds number product are unsuitable parameters for the flow through ducts of complex geometry.
Dynamical properties of premartensitic NiTi

Acoustic phonon branches of equiatomic NiTi have been investigated by inelastic neutron scattering. A commensurate condensation of the T2A (110) phonon mode at q110=qmax/3, Tc=75 degrees C and a normal behaviour of the LA (111) phonon branch is found.
On a Nonlinear Elliptic Eigenvalue Problem

Let N(λ )be the number of the solutions of the equation: −�u = λf (u) in Ω, u= 0o n∂Ω ,w here Ω is a bounded domain in R N (N 2) with smooth boundary. Under suitable conditions on f ,w e
Minimal sets and chain recurrent sets of projective flows induced from minimal flows on $3$-manifolds

A nonsingular flow $\varphi_t$ on a $3$-manifold induces a flow on the plane bundle orthogonal to $\varphi_t$ by the derivative. This flow also induces a flow $\psi_t$ on its projectivized bundle $PX$, which is called the projective flow. In this paper, we will investigate this projective flow in order to understand the original flow $\varphi_t$, in particular, under the condition that $\varphi_t$ is minimal and $\psi_t$ has more than one minimal sets: If the projective flow $\psi_t$ has more than two minimal sets, then we will show that $\varphi_t$ is topologically equivalent to an irrational flow on the $3$-torus. In the case when $\psi_t$ has exactly two minimal sets, then we obtain several properties of the minimal sets of $\psi_t$. In particular, we construct two $C^\infty$ sections to $PX$ which separate these minimal sets (and hence $PX$ is a trivial bundle) if $\varphi_t$ is not topologically equivalent to an irrational flow on the $3$-torus. As an application of this characterization, the chain recurrent set of the projective flow is shown to be the whole $PX$.
Stress in oxidized porous silicon layers

Stress was determined in oxidized porous silicon layers using x‐ray diffraction to measure the substrate curvature. Stress is always compressive and its magnitude depends on oxide quality. The maximum value is reached when the oxide obtained from porous silicon is densified by a high‐temperature process and is equivalent to standard thermal silicon dioxide. The stress magnitude decreases when oxide porosity increases. An increase in layer thickness is always observed when oxidation conditions lead to a porous oxide or when the initial porosity of the layer is lower than 56%, due to volumic expansion of silica relative to silicon, otherwise the thickness decreases.
COINTEGRATING REGRESSIONS WITH TIME VARYING COEFFICIENTS

This paper considers cointegrating regressions with time varying coefficients. The coefficients are modeled as smooth functions evolving over time. It is shown that they can be estimated nonparametrically, using suitably modified series estimators. Presented is the efficient method of estimation, which relies on simple prefiltering of the data and preestimation of the model. The test for the adequacy of model specification is also developed. Our model and statistical methods are applied to analyze the U.S. automobile demand function.
Model selection and clustering in stochastic block models based on the exact integrated complete data likelihood

The stochastic block model (SBM) is a mixture model for the clustering of nodes in networks. The SBM has now been employed for more than a decade to analyze very different types of networks in many scientific fields, including biology and the social sciences. Recently, an analytical expression based on the collapsing of the SBM parameters has been proposed, in combination with a sampling procedure that allows the clustering of the vertices and the estimation of the number of clusters to be performed simultaneously. Although the corresponding algorithm can technically accommodate up to 10 000 nodes and millions of edges, the Markov chain, however, tends to exhibit poor mixing properties, that is, low acceptance rates, for large networks. Therefore, the number of clusters tends to be highly overestimated, even for a very large number of samples. In this article, we rely on a similar expression, which we call the integrated complete data log likelihood, and propose a greedy inference algorithm that focuses on maximizing this exact quantity. This algorithm incurs a smaller computational cost than existing inference techniques for the SBM and can be employed to analyze large networks (several tens of thousands of nodes and millions of edges) with no convergence problems. Using toy datasets, the algorithm exhibits improvements over existing strategies, both in terms of clustering and model selection. An application to a network of blogs related to illustrations and comics is also provided.
Mathematics of Marital Conflict: Qualitative Dynamic Mathematical Modeling of Marital Interaction

This article presents a new nonstatistical mathematical approach to modeling marital interaction by means of nonlinear difference equations. The application made of this modeling process in this article is to generate theory in order to understand J. M. Gottman and R. W. Levenson's (1992) report of the ability of one variable derived from a balance view of marital interaction to predict marital dissolution in a prospective study. Parameters are introduced that reflect uninfluenced husband and wife set points, emotional inertia, and influence function. These parameters are subjected to various examinations of validity with other data that reflect patterns of marital interaction and the cascade toward marital dissolution. Results suggest the hypothesis that unstable marriages are characterized at Time 1 by a mismatch in husband and wife influence functions. The modeling method makes it possible to fit a couple's equations under one set of conditions, then to simulate the couple's interaction under different conditions, and then to conduct experiments to test the validity of these simulations. The method provides a new approach toward the building of theory in family psychology. This article introduces a new approach to the modeling of social interaction using the mathematics of difference and differential equations. These equations express, in mathematical form, a proposed mechanism of change over time. They do not represent a statistical approach to modeling; rather they are designed to suggest a precise mechanism of change. This method has been used with great success in the biological sciences (Murray, 1989). The method is usually a quantitative approach that requires the modeler to be able to write down in mathematical form, on the basis of some theory, the causes of change in the dependent variables. For example, in the classic predator-prey problem, a modeler writes down that the rate of change in the population densities is some function of the current densities (e.g., Murray, 1989). Although this
Atomic data for resonance absorption lines. I, Wavelengths longward of the Lyman limit

This compilation presents wavelengths, statistical weights, and excitation energies for 2031 atomic spectral lines in 658 multiplets whose lower energy levels lie below 2217 cm −1 or 0.275 eV. Transition probabilities and oscillator strengths (f-values) are included for most of the lines, and radiation damping constants for many of the stronger ones. This list of resonance lines contains the transitions likely to be observed in absorption in interstellar gas clouds, circumstellar shells, stellar winds, QSO winds, and clouds on the sight lines to QSOs, where neither the particle density nor the radiation density is large enough to populate the higher levels significantly.
Low-noise S-band DC SQUID based amplifier

A low-noise rf amplifier based on a dc SQUID (SQA) is tested in the frequency range 3.3-4.1 GHz. A new signal launching system for the SQA rf coupling has been developed and successfully implemented. The following parameters have been measured at 3.65 GHz using a band-pass filter at the input of a single-stage SQA: gain (11.0/spl plusmn/1.0) dB, 3 dB bandwidth of 300 MHz and noise temperature (4.0/spl plusmn/1.0)K. This figure corresponds to a flux noise S/sub /spl Phi///sup 1/2 /=0.6 /spl mu//spl Phi//sub 0//Hz/sup 1/2 / and an energy sensitivity /spl epsi//sub i//spl ap/75 h. The input saturation power, P/sub s/, (1 dB gain compression) is measured for different bandwidths of the input band-pass filter, A corresponding input signal saturation temperature (normalized for a 1 GHz bandwidth) T/sub SAT//sup 1GHZ/=P/sub SAT//k/sub B/ is estimated to be 11.5 K GHz at an SQA bias voltage 27 /spl mu/V (condition for minimum noise temperature). The dependencies of the SQA gain, noise temperature and saturation level on the operation point are studied. The reason for the SQA saturation is discussed.
A vendor–buyer integrated production-inventory model with quantity discount and unequal sized shipments

This paper considers a single-vendor single-buyer integrated production-inventory model for a single product. The vendor offers a quantity discount to motivate the buyer to buy more quantities and he delivers the buyer’s order quantity in a number of unequal sized shipments. The proposed model is formulated and the optimal decisions are obtained by minimising the average total cost of the integrated system. A numerical example is taken to illustrate the developed model.
Motion of a curved vortex filament with decaying vortical core and axial velocity

The motion and decay of a vortex filament with large axial and circumferential velocity components in a three-dimensional stream are studied. Solutions are constructed to the Navier–Stokes equations by use of matched asymptotic expansions; the small parameter used is a measure of the ratio of the viscous effects to the vortex strength. The outer flow, which corresponds to the classical Biot–Savart type analysis is matched to the solution in an inner viscous region. The radius of the viscous core is assumed to be much smaller than the radius of curvature. The present viscous analysis yields the classical inviscid theory as a limiting case for the leading term in the outer region and thus can be used to correct various deficiencies in the latter. We show in particular, that the inner solution yields a finite velocity at all points in the filament and we determine how the components of both vorticity and velocity diffuse due to the viscous forces. The matching conditions guarantee the continuity of velocity .
On arcs sharing the maximum number of points with ovals in cyclic affine planes of odd order

The sporadic complete 12‐arc in PG(2, 13) contains eight points from a conic. In PG(2,q) with q>13 odd, all known complete k‐arcs sharing exactly ½(q+3) points with a conic 𝒞 have size at most ½(q+3)+2, with only two exceptions, both due to Pellegrino, which are complete (½(q+3)+3) arcs, one in PG(2, 19) and another in PG(2, 43). Here, three further exceptions are exhibited, namely a complete (½(q+3)+4)‐arc in PG(2, 17), and two complete (½(q+3)+3)‐arcs, one in PG(2, 27) and another in PG(2, 59). The main result is Theorem 6.1 which shows the existence of a (½(qr+3)+3)‐arc in PG(2,qr) with r odd and q≡3 (mod 4) sharing ½(qr+3) points with a conic, whenever PG(2,q) has a (½(qr+3)+3)‐arc sharing ½(qr+3) points with a conic. A survey of results for smaller q obtained with the use of the MAGMA package is also presented. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 25–47, 2010
On the Order of Uniprimitive Permutation Groups

One of the central problems of 19th century group theory was the estimation of the order of a primitive permutation group G of degree n, where G X An. We prove I G I < exp (4V'/ n log2 n) for the case when G is not doubly transitive. This result is best possible apart from an O(log n) factor in the exponent. The best result previously known was I G I < el (H. Wielandt). A similar estimate for the doubly transitive case follows in a subsequent paper. For rank 3 groups with subdegree p < n/2 we obtain I GI < exp (4(n/p) log2 n). In the proof we develop some new combinatorial properties of coherent configurations. The results also have relevance to theoretical estimates on the computational complexity of graph isomorphism testing.
Log-Linear Transformation of Binary Variables: A Suitable Input for SEM

A great obstacle for wider use of structural equation modeling (SEM) has been the difficulty in handling categorical variables. Two data sets with known structure between 2 related binary outcomes and 4 independent binary variables were generated. Four SEM strategies and resulting apparent validity were tested: robust maximum likelihood (ML), tetrachoric correlation matrix input followed by SEM ML analysis, SEM ML estimation for the sum of squares and cross-products (SSCP) matrix input obtained by the log-linear model that treated all variables as dependent, and asymptotic distribution-free (ADF) SEM estimation. SEM based on the SSCP matrix obtained by the log-linear model and SEM using robust ML estimation correctly identified the structural relation between the variables. SEM using ADF added an extra parameter. SEM based on tetrachoric correlation input did not specify the data generating process correctly. Apparent validity was similar for all models presented. Data transformation used in log-linear modeling can serve as an input for SEM.
Josephson-junction arrays as high-efficiency sources of coherent millimeter-wave radiation

Recent experiments have indicated that Josephson-junction arrays can radiate coherently in a laser-like fashion, as predicted by theoretical work in the 1970s. We present results from measurements of high-efficiency Josephson-junction arrays coupled to resonant cavities. In one of our samples with four columns and 36 rows, the dc to ac (180 GHz) conversion efficiency reaches an asymptotic value of about 32%. Using a simple circuit model we show that we have achieved optimal dc to ac conversion in this sample.
SHEWHART AND ZONE CONTROL CHART PERFORMANCE UNDER LINEAR TREND

ABSTRACT The average run length performances of Shewhart charts with supplementary runs rules and zone control charts are studied when the process mean changes linearly over time. Shewhart charts with all possible combinations of the typical runs rules are compared to zone control charts with identical false alarm rates. The zone control charts generally outperform the Shewhart charts in detecting a process mean that is changing linearly over time.
Preparation of RhO2 Thin Films by Reactive Sputtering and Their Characterizations

Thin films of RhO2, which belongs to the family of conducting platinum group metal oxides, were prepared by reactive sputtering. Influences of sputtering parameters, such as rf power and substrate temperature, and postdeposition annealing on crystallinity, chemical bonding state and resistivity of the deposited films were studied, in order to obtain low-resistivity RhO2 thin films. The resistivity of the deposited films decreased with decreasing rf power. Plasma emission measurement suggested that oxidation of Rh proceeded under the low rf power condition. Poorly-crystallized conducting RhO2 thin films with resistivity of 300–500 µΩcm were prepared at substrate temperatures below 150°C; the resistivity of the films increased with increasing substrate temperature above 150°C due to the formation of semiconducting Rh2O3. After postdeposition annealing in oxygen atmosphere at up to 700°C, well-crystallized RhO2 films were formed, and the minimum resistivity of 80 µΩcm was obtained.
Identification of field dwarfs and giants in the second Radial Velocity Experiment Data Release

The second Radial Velocity Experiment (RAVE) Data Release (DR2) derives log g values. However, we present a simpler and cleaner method of identifying dwarfs and giants by using only magnitudes, which does not require spectroscopic analysis. We confirm the method presented in an earlier paper, with which we estimate the number of dwarfs and giants using their positions in the J–V two-magnitude diagram, by applying it to RAVE DR2. It is effective in estimating the number of dwarfs and giants at J–H > 0.4 compared to RAVE’s log g values. For J–H≤ 0.4, where dwarfs and subgiants show a continuous transition in the J magnitude histogram, we used the Besancon Galaxy model predictions to statistically isolate giants. The percentages of giants for red stars and for the whole sample are 85 and 34 per cent, respectively. If we add the subgiants, the percentage of evolved stars for the whole sample increases to 59 per cent. For the first time in the literature, we have analysed the effect of CHISQ on RAVE’s log g values (CHISQ is the penalized χ2 from RAVE’s technique of finding an optimal match between the observed spectrum and synthetic spectra to derive stellar parameters). Neither the CHISQ values nor the signal-to-noise ratio bias the RAVE log g values. Therefore, the method of identifying dwarfs and giants using the two-magnitude diagram has been verified against an unbiased data set.