Miracle-dz/UniFAR-FTUs huggingface dataset:
On the stabilizability of multiple integrators by means of bounded feedback controls

It is known that a linear system x=Ax+Bu can be stabilized by means of a smooth bounded control if and only if it has no eigenvalues with positive real part, and all the uncontrollable modes have a negative real part. The authors investigate, for single-input systems, the question of whether such systems can be stabilized by means of a feedback u= sigma (h(x)), where h is linear and sigma (s) is a saturation function such as sign(s) min( mod s mod ,1). A stabilizing feedback of this particular form exists if A has no multiple eigenvalues, and also in some other special cases such as the double integrator. It is shown that for the multiple integrator of order n, with n>or=3, no saturation of a linear feedback can be globally stabilizing. <<ETX>>
Nonlinear seismic performance of RC bridges using the ESA, EDA, DDBA, and nonlinear analysis with various viscous damping models

Modern bridge seismic design follows a performance-based seismic design (PBSD) philosophy where the structure is designed to achieve a prescribed limit state under a defined hazard. Nevertheless, the demands may substantially diverge depending on the PBSD method applied in the assessment. This article presents a demand sensitivity analysis using the elastic (ESA) and dynamic (EDA) procedures of the AASHTO Seismic Guide Specifications and direct displacement-based assessment (DDBA). The investigation was conducted using 81 reinforced concrete (RC) bridges and ten multi-period spectra from a shallow tectonic regime. Moreover, these demands were compared with nonlinear time history analysis (NLTHA) using five viscous damping models. Seven compatible records were employed to calculate the envelopes of transverse displaced shapes and cumulative distribution functions of the column with the highest displacement ductility. These average inelastic responses were contrasted with the predictions from the ESA, EDA, and DDBA. For regular bridges, this study found that the elastic procedures considerably underestimate the deformations, while DDBA compares well with NLTHA, especially for high ductility levels. Also, a discussion about the impact of the viscous damping models is included. We expect these findings may encourage practitioners to use DDBA as a reliable alternative to evaluate the seismic performance of RC bridges.
Using Gurney Flaps to Control Laminar Separation on Linear Cascade Blades

This paper describes an experimental investigation of the use of Gurney flaps to control laminar separation on turbine blades in a linear cascade. Measurements were made at Reynolds numbers (based upon inlet velocity and axial chord) of 28×10 3 , 65×10 3 and 167×10 3 . The freestream turbulence intensity for all three cases was 0.8%. Laminar separation was present on the suction surface of the Langston blade shape for the two lower Reynolds numbers. In an effort to control the laminar separation, Gurney flaps were added to the pressure surface close to the trailing edge. The measurements indicate that the flaps turn and accelerate the flow in the blade passage toward the suction surface of the neighboring blade thereby eliminating the separation bubble. Five different sizes of Gurney flaps, ranging from 0.6 to 2.7% of axial chord, were tested. The laser thermal tuft technique was used to determine the influence of the Gurney flaps on the location and size of the separation bubble. Additionally, measurements of wall static pressure, profile loss, and blade-exit flow angle were made. The blade pressure distribution indicates that the lift generated by the blade is increased. As was expected, the Gurney flap also produced a larger wake. In practice, Gurney flaps might possibly be implemented in a semi-passive manner. They could be deployed for low Reynolds number operation and then retracted at high Reynolds numbers when separation is not present. This work is important because it describes a successful means for eliminating the separation bubble while characterizing both the potential performance improvement and the penalties associated with this semi-passive flow control technique.
Collaborative Watershed Modeling as Stakeholder Engagement Tool for Science-Based Water Policy Assessment in São Paulo, Brazil

This study describes a collaborative modeling process deployed at the Cantareira Water Supply System (CWSS) in São Paulo City Metropolitan Area, Brazil. The CWSS faces challenges for meeting the increasing water demand, while land-use and climate change and their combined effect on its water cycle and balance have created a complex water resources management problem. Through a stakeholder engagement process—involving scientists and policymakers, the water utility company, and state administration—environmental simulation models were developed to elicit and represent multiple environmental, economic, and policy perspectives, developing a mutual language to communicate and establish common goals of water resources management. Study outputs include estimation of biophysical and economic benefits associated with prioritized native vegetation restoration activities in the source watersheds. These outputs are deployed in support of landscape planning and the decision process integrating multiple stakeholder perspectives in São Paulo state administration, the water utility company, and municipalities.
A Galactic Center 50-kms$^{-1}$ Molecular Cloud with an Expanding Shell

We performed high-resolution observations of a Galactic Center 50-km s � 1 molecular cloud in the CS J = 1–0 line using the Nobeyama Millimeter Array (NMA). The molecular cloud mainly has three different spatial components with large velocity widths of up to 60 km s � 1 . The northwest component is located at an apparent contact point to the Sgr A east shell, and elongated along the boundary of the shell. The large velocity width of the component is responsible for interaction with the Sgr A east shell. The molecular gas distribution in CS line emission is dissimilar to that observed previously in NH3 line emissions. The appearance shows presumably the area of CS line emission enhanced by shock. The central and southwest components are located just out of the Sgr A east shell and far from it, respectively. However, these components have large velocity widths. We found a well-shaped circular molecular shell with expanding motion in the 50-km s � 1 molecular cloud. This is responsible for the large velocity width. The continuum source in the expanding molecular shell has a steep spectrum in mmwavelengths, although this was not identified in a previous 5-GHz map. This source may be an SNR with an ionized sheath. From the aspect ratio of an expanding molecular shell of 1.1, the magnetic field in/around the shell is estimated to be smaller than 100 � Gauss. This weak magnetic field is consistent with on-going active star formation in the 50-km s � 1 molecular cloud. A comparison among CS line emission, low-frequency continuum, and millimeter continuum toward the 50-km s � 1 molecular cloud suggests a face-on view of the Sgr A region. The molecular cloud
The distribution function of diffuse ions and the magnetic field power spectrum upstream of Earth's bow shock

During two diffuse energetic ion events upstream of the Earth's bow shock with radial interplanetary magnetic field conditions comprehensive energy spectra of the protons and power spectra of the magnetic field fluctuations were obtained with the instrumentation on AMPTE/IRM. For diffuse ions a continuous distribution from ≈ 5 keV (starting above the solar wind energy) to the instrumental limit (230 keV/e) is found upstream and downstream of the shock. This strongly indicates a single source for the upstream diffuse ion population over the total energy range. Assuming that the ions are shock accelerated, an efficiency for the production of upstream energetic ions of ≈ 4 to 11% is found by comparing the energy flux densities of the energetic ions and of the incoming solar wind. The lower value is observed during the period with a low interplanetary magnetic field strength. The measured energy densities of the particles and the waves are compared with the self-consistent model of Fermi acceleration by Lee (1982) which includes the coupled wave and particle behaviour. The theoretically predicted wave energy density is in excellent agreement with the observed wave energy density.
Optional Feature Vector Generation for Linear Value Function Approximation with Binary Features

Linear value function approximation with binary features is important in the research of Reinforcement Learning (RL). When updating the value function, it is necessary to generate a feature vector which contains the features that should be updated. In high dimensional domains, the generation process will take lot more time, which reduces the performance of algorithm a lot. Hence, this paper introduces Optional Feature Vector Generation (OFVG) algorithm as an improved method to generate feature vectors that can be combined with any online, value-based RL method that uses and expands binary features. This paper shows empirically that OFVG performs well in high dimensional domains.
Coronal mass ejections: The key to major interplanetary and geomagnetic disturbances

For years it was thought that solar flares were responsible for major interplanetary (IP) particle events and geomagnetic storms. However, recently we have seen an important paradigm shift such that now coronal mass ejections (CMEs), not flares, are considered the key causal link with solar activity. CMEs are vast structures of plasma and magnetic fields that are expelled from the sun into the heliosphere. We now know that CMEs drive all large geomagnetic storms and their attendant effects, such as auroral displays. Fast CMEs produce transient IP shocks which cause sudden commencements at Earth. The CME-related shocks also accelerate the solar energetic particle (SEP) events associated with major IP disturbances and with radiation hazards at Earth. This new paradigm has important implications for prioritizing the development of instruments and techniques to predict IP disturbances and geomagnetic activity.
Finite-Time Control of Markov Jump Lur'e Systems With Singular Perturbations

This article investigates the asynchronous controller design issue for Markov jump Lur'e systems with singular perturbations within a fixed time interval. For broader practical applications, the variation of system modes is regulated by a switched nonhomogeneous Markov process that corresponded to both lower level nonhomogeneous stochastic jumping and higher level deterministic switching. By resorting to the hidden nonhomogeneous-Markov model, an asynchronous control law that relies on the detected mode information is proposed. In light of the mode-dependent average dwell time strategy and mode-dependent stochastic system theory, the singularly perturbed parameter-independent conditions are attained to ensure the stochastic finite-time boundedness of the resulting systems. With respect to a linear matrix inequality optimization problem, a solution to the maximum singular perturbation parameter is obtained. Finally, the feasibility and applicability of the devised theoretical results are verified by simulation examples.
Airborne and ground‐based studies of thunderstorms in the vicinity of Langmuir Laboratory

Flights through the central regions of thunderstorms were made over New Mexico on 6 and 15 August 1977 with the ONR/NMIMT Schweitzer aeroplane which carried equipment designed to measure all three components of the electric field, and the charge, Q, and diameter, d, of individual precipitation elements. On the earlier day, information was also obtained with: a rain-gauge network surrounding Langmuir Laboratory; a 3 cm radar; an acoustic system for locating lightning channels; a ground-based field-change meter. The first cell on 6 August produced precipitation at the ground but no lightning. Vertical fields, Ex, of up to about 50kVm−1 and precipitation charge densities ρ of up to −0.5 C km−3 were recorded within the cloud. The second cell, which grew as the first one decayed, produced 7 lightning strokes in 9 minutes during which time the radar revealed vigorous vertical growth in a narrow zone containing precipitation. Thunder reconstructions showed the acoustic sources for the first flash of this cell to be very near the top of the cloud at an altitude of 10 km a.s. 1. The subsequent flashes produced acoustic signals from progressively lower in the cloud. When the radar echo reached its maximum height lightning activity ceased. Ex values of up to about 50kVm−1 and pp values of down to −1 Ckm−3 were measured. ρp was consistently negative, individual charges being less than ±40 pC. Q values were within the inductive limit for a thundercloud at breakdown but no systematic relation between Q and d was found. Six penetrations were made through the thundercloud of 15 August, which produced only two lightning strokes. The Ex records were indicative of a (±) dipole located near the cloud top, at around –13°C. Fields of up to about 100kVm−1 and ρp values (positive and negative) of around 5Ckm−3 were measured. Q values of up to ±250 pC were recorded, with charges around ±50 pC being commonly found. No systematic Q-d relation was revealed, and smaller precipitation particles frequently carried charges (positive or negative) in excess of the inductive limit. On both days estimated precipitation rates were of order 10mmh−1 and on most occasions the pilot reported precipitation particles to be either ‘ice’ or ‘mixed liquid water and ice’.
Forced drop swinging on vibrated and textured metal substrates

A new type of vibrated drop wettability mechanism on a micro‐texture surface is proposed and investigated experimentally and theoretically. In this experiment, the mechanical testing machine is used as the vibration source, and the compound control cabinet is used to adjust the vibration liquid feeding table. By comparing the apparent dynamic contact angle, it is concluded that the surface energy of the second cycle is larger than the first one. A swing model and spring‐mass system model are presented to study the vibrated drop motion pattern. The spring‐mass system model is built to analyse the adhesion force working process theoretically. The drop surface energy is transmitted by vibration. With the superposition of vibration energy, the displacement of the drop gravity centre becomes larger and larger until the drop migrates. The adhesion force drives the liquid drop to do reciprocating motion, and it changes the liquid drop dynamic wettability.
Effects of chemical stoichiometry of channel region on bias instability in ZnO thin-film transistors

We investigated effects of chemical stoichiometry of ZnO channel, controlled by oxygen partial pressure during deposition, on bias instability for ZnO thin-film transistors. Parallel threshold voltage shifts were mainly enhanced under gate bias stresses due to charge trapping when O-rich ZnO was used for channel layer. On the contrary, negative threshold voltage shifts were observed under both gate and drain bias stresses when Zn-rich ZnO was used for channel layer. This degradation was enhanced regardless of the bias polarity and the direction, attributing to electrically activated trap generations.
Automatic relevance determination for multi‐way models

Estimating the adequate number of components is an important yet difficult problem in multi‐way modeling. We demonstrate how a Bayesian framework for model selection based on automatic relevance determination (ARD) can be adapted to the Tucker and CandeComp/PARAFAC (CP) models. By assigning priors for the model parameters and learning the hyperparameters of these priors the method is able to turn off excess components and simplify the core structure at a computational cost of fitting the conventional Tucker/CP model. To investigate the impact of the choice of priors we based the ARD on both Laplace and Gaussian priors corresponding to regularization by the sparsity promoting l1‐norm and the conventional l2‐norm, respectively. While the form of the priors had limited effect on the results obtained the ARD approach turned out to form a useful, simple, and efficient tool for selecting the adequate number of components of data within the Tucker and CP structure. For the Tucker and CP model the approach performs better than heuristics such as the Bayesian information criterion (BIC), Akaikes information criterion (AIC), DIFFIT and the numerical convex hull (NumConvHull) while operating only at the cost of estimating an ordinary CP/Tucker model. For the CP model the ARD approach performs almost as well as the core consistency diagnostic (CorConDiag). Thus, the ARD framework is a simple yet efficient tool for the estimation of the adequate number of components in multi‐way models. A Matlab implementation of the proposed algorithm is available for download at www.erpwavelab. org. Copyright © 2009 John Wiley & Sons, Ltd.
Using program schemes to capture polynomial-time logically on certain classes of structures.

We continue the study of the expressive power of certain classes of program schemes on finite structures, in relation to more mainstream logics studied in finite model theory and to computational complexity. We show that there exists a program scheme, whose constructs are assignments and while-loops with quantifier-free tests and which has access to a stack, that can accept a P-complete problem, the deterministic path system problem, even in the absence of non-determinism so long as problem instances are presented in a functional style. (Our proof leans heavily on Cook's proof that the classes of formal languages accepted by deterministic and non-deterministic logspace auxiliary pushdown machines coincide). However, whilst our result is of independent interest, as it leads to a deterministic model of computation capturing P whose non-deterministic variant also captures P, we then show how our constructed program scheme can be used to build a successor relation in certain classes of structures, namely: the class of strongly-connected locally-ordered digraphs; the class of connected planar embeddings; and the class of triangulations, with the consequence that on these classes of graphs, (a fragment of) path system logic (with no built-in relations) captures exactly the polynomial-time solvable problems.
Sparse inverse covariance matrices and efficient maximum likelihood classification of hyperspectral data

Abstract The inverse covariance matrix of a block of Airborne Visible/ Infrared Imaging Spectrometer (AVIRIS) hyperspectral data tends towards a sparse, band-diagonal form. This matrix is used in the quadratic form of the discriminant function of a maximum likelihood classifier (MLC). It can be written in a formal way as a function of partial and multiple correlation coefficients. This allows one to interpret the sparse form of the inverse covariance matrix to show where the important inter-band information lies in a hyperspectral image. Using these results, MLC is related to multiple linear regression, and one finds that the noise in each band becomes an important factor. With the understanding this theoretical analysis engenders, three families of approximations to full MLC are developed which capture most of the information it uses but which are much more efficient both to train and to evaluate during classification of a whole image. The essence of the new methods is to approximate the inverse covarian.
Support Vector Machine-based Denoising Technique for Removal of White Noise in Partial Discharge Signal

Abstract—Partial discharge (PD) measurement has emerged as a dominant investigative tool for condition monitoring of insulation in high voltage equipment. In general, PD signals are severely polluted by several noises like white noise, random noise, discrete spectral interferences (DSI). The challenge lies with removing these noises from PD signal effectively by preserving the signal features. In this article, support vector machine (SVM) based denoising technique has been proposed for the removal of white noise from PD signal. The proposed SVM technique retains the edge of the original signal efficiently and also pseudo Gibbs phenomenon does not exist with SVM technique. In order to evaluate the effectiveness of the proposed method, artificially simulated PD signal mixed with white noise and the measured PD readings are considered. For the purpose of comparison, other denoising techniques such as fast Fourier transform (FFT), discrete wavelet transform (DWT), and translation invariant wavelet transform (TIWT) are also considered. The results reveal that, SVM based denoising technique shows better performance in terms of higher signal to noise ratio, signal reconstruction error ratio, cross correlation coefficient and reduction in noise level, mean square error, and waveform distortion.
Elliptic Curves and Quadratic Recurrence Sequences

The explicit solution of a general three‐term bilinear recurrence relation of fourth order is constructed here in terms of the Weierstrass sigma function. The construction of the elliptic curve associated to the Somos 4 sequence is presented as an example. An interpretation via the theory of integrable systems is provided, leading to a conjecture relating certain higher‐order recurrences with hyperelliptic curves of higher genus. 2000 Mathematics Subject Classification 11B37 (primary), 33E05, 37J35 (secondary).
A fast method for global surface interpolation

A fast algorithm is presented for a globally smooth interpolation for a visual surface from scattered range data. This method is based on matching lower order spatial moments, where the reconstructed surface is given by a linear combination of Legendre polynomials. This method can handle data that do not lie on a regular grid. The value of the function at points where the grid is not defined, or where the original data is missing, can be approximated from the constituent polynomials. Some simulation experiments evaluate the performance of the proposed scheme. An arbitrarily shaped surface is shown on a 35*35 grid, and the depth information is available only at a few selected grid points. The result of the implementation of Grimson's (1981) algorithm where the surface is constrained to pass through the given data set is given. The proposed method runs much faster than Grimson's algorithm. The coefficients of the Legendre polynomials can be precomputed. <<ETX>>
Zero-biased near-ultraviolet and visible photodetector based on ZnO nanorods/n-Si heterojunction

N-ZnO nanorods/n-silicon heterojunction was fabricated by growth of ZnO nanorods on a n-type silicon (111) wafer with a low-temperature aqueous solution method. Capacitance-voltage measurements revealed that after annealing at 900 °C in O2 ambient for 1 h, the heterojunction changed from abrupt N-ZnO nanorods/n-silicon to graded P-ZnO/n-silicon junction. The annealed diode showed good photoresponse in both the ultraviolet and visible regions with responsivity around 0.3 and 0.5 A/W without bias. The photoresponses toward ultraviolet and visible light were enhanced when the diode was under reverse and forward bias, respectively. The results were discussed in terms of phosphorus diffusion process and the band diagrams of the heterojunctions in this work.
Synchronization criteria for coupled Hopfield neural networks with time-varying delays

This paper proposes new delay-dependent synchronization criteria for coupled Hopfield neural networks with time-varying delays. By construction of a suitable Lyapunov—Krasovskii's functional and use of Finsler's lemma, novel synchronization criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.