Miracle-dz/UniFAR-FTUs huggingface dataset:
Multivariate Prediction using Softly Shrunk Reduced-Rank Regression

Abstract Multivariate regression is considered with emphasis on prediction. Ordinary least squares tends to yield unstable estimates and consequently uncertain predictions when there are few observations in the training data compared to the number of parameters to be estimated. Thus, there is a need for methods that work well in such situations. This article presents a new alternative prediction method based on reduced-rank regression. The method of reduced-rank regression uses a certain decomposition of the ordinary least squares estimate of the matrix of regression coefficients, and shrinks the last terms of this decomposition exactly to 0. I suggest a new method with soft shrinkage of the terms in the decomposition. Furthermore, the reduced-rank regression, as well as the new softly shrunk reduced-rank regression, are combined with principal components regression. The methods are modified to handle missing observations in the response variables. The various methods are compared through a simulation study. Softly shrunk reduced-rank regression, possibly combined with principal components, turns out to be the best overall method, and the improvement over ordinary least squares is particularly large in situations with few observations.
Regression Models for Count Data in R

The classical Poisson, geometric and negative binomial regression models for count data belong to the family of generalized linear models and are available at the core of the statistics toolbox in the R system for statistical computing. After reviewing the conceptual and computational features of these methods, a new implementation of zero-inflated and hurdle regression models in the functions zeroinfl() and hurdle() from the package pscl is introduced. It re-uses design and functionality of the basic R functions just as the underlying conceptual tools extend the classical models. Both model classes are able to incorporate over-dispersion and excess zeros - two problems that typically occur in count data sets in economics and the social and political sciences - better than their classical counterparts. Using cross-section data on the demand for medical care, it is illustrated how the classical as well as the zero-augmented models can be fitted, inspected and tested in practice.
Numerical Study for Optimizing Heat Transfer in High Speed Rotating Components

Cooling of high speed rotating components is a typical situation found in turbomachinery as well as in automobile engines. Accurate knowledge of discharge coefficients and heat transfer of related components is essential for the high performance of the whole engine. This can be achieved by minimized cooling air flows and avoidance of hot spots. In high speed rotating clutches for example aerodynamic investigations improving heat transfer have not been considered in the past. Advanced concepts of modern plate design try to reduce thermal loads by convective cooling methods. Therefore, secondary cooling air flows have to be enhanced by an appropriate design of the rotor stator system with orifices. CFD modelling is used to improve the basic understanding of the flow field in typical geometries used in these systems.
Quantifying glucose permeability and enhanced light penetration in ex vivo human normal and cancerous esophagus tissues with optical coherence tomography

We report our pilot results on quantification of glucose (G) diffusion permeability in human normal esophagus and ESCC tissues in vitro by using OCT technique. The permeability coefficient of 40% aqueous solution of G was found to be (1.74±0.04)×10-5 cm/s in normal esophagus and (2.45±0.06)×10-5 cm/s in ESCC tissues. The results from this study indicate that ESCC tissues had a higher permeability coefficient compared to normal esophageal tissues, and the light penetration depths gradually increase with the increase of applied topically with G time for the normal esophageal and ESCC tissues. The results indicate that the permeability coefficient of G in cancer tissues was 1.41-fold than that in normal tissues, and the light penetration depth for the ESCC tissues is significantly smaller than that of normal esophagus tissues in the same time range. These results demonstrate that the optical clearing of normal and cancer esophagus tissues are improved after application of G.
A unified theory of dipolophoresis for nanoparticles

General mobility relations are derived for the translation and rotation of submicrometer-size freely suspended conducting (ideally polarizable) particles of arbitrary shape under dc or ac spatially nonuniform electric forcing. Both linear electrophoretic effects for an initially charged colloid and nonlinear induced-charge electrophoresis of an uncharged particle are considered within the same framework. A concise derivation of the total loads (electrostatic and hydrodynamic) exerted on a single colloid are obtained by integrating the Maxwell, shear and normal (relating to the unsteady Stokes equation) stresses over the particle. These newly derived expressions for the force and torque exerted on a nanoparticle, which is subject to any electric field, are given for an arbitrary Debye thickness and thus open the road to studying nonlinear phoretic motions on the nanoscale.
Characterization of two different orientations of epitaxial niobium thin films grown on MgO(001) surfaces

Epitaxial Nb thin films deposited onto the same crystalline insulating surface can evolve in very different fashions depending on specific deposition conditions, thereby affecting their microstructure, surface morphology and superconducting properties. Here, we examine and compare the microstructure and ensuing surface morphology from two distinct Nb/MgO series each with its own epitaxial registry—namely Nb(001)/MgO(001) and Nb(110)/MgO(001)—leading to distinct surface anisotropy and we closely examine the dynamical scaling of the surface features during growth. We compare our findings with those in other metal/MgO epitaxial systems and for the first time, general scaling formalism is applied to analyze anisotropic surfaces exhibiting biaxial symmetry. Further, Power Spectral Density is applied to the specific problem of thin film growth and surface evolution to qualify the set of deposition conditions leading to smoother surfaces. We find good correlation between the surface morphology and microstructure of the various Nb films with superconducting properties such as their residual resistance ratio and lower critical field.
Control of the Rayleigh–Taylor instability in a staged Z pinch

Z-pinch experiments and computer simulations provide evidence for enhanced stability and current transfer in a staged Z pinch, consisting of an annular krypton shell imploding onto a deuterium gas fill. Visible-streak and Schlieren imaging provide evidence for a multilayer implosion where the outer plasma shell is Rayleigh–Taylor unstable and the inner plasma column is stable. Computer simulations indicate that the discharge current diffuses through the unstable, outer Kr shell. As the discharge current layer implodes onto the deuterium, current is transferred and a stable implosion results, producing a deuterium-compression ratio of 200.
Automatic Lens Design by the Least Squares Method

The method of least squares which permits the simultaneous variation of a large number of design parameters, has been adapted for use with the Weizmann Institute of Science electronic digital computer. The minimization process is iterated until a satisfactory solution is obtained.Two programs are described, for the correction of third-order aberrations and of residual aberrations, respectively. The time required to complete one iteration is 0.5 sec per surface per parameter for the first program, the corresponding time for the final correction being 3.5 sec.Examples of actual applications of the method for the correction of a Cooke triplet and of a Tessar system are presented.
Adaptive identification of linear time‐delay systems

Synthesis of an adaptive parameter identifier is developed for linear dynamic systems with finitely many lumped delays in the state vector and control input. These systems are governed by linear functional differential equations with uncertain time‐invariant parameters and delays. The state of the system is assumed to be available for measurements. Constructive necessary and sufficient conditions for the system parameters and delays to be identifiable are provided. Once the parameter identifiability is guaranteed the simultaneous on‐line identification of the system parameters and delays is achieved by the adaptive identifier proposed. Theoretical results are supported by numerical simulation. Copyright © 2003 John Wiley & Sons, Ltd.
Test of a Poor Man's Ensemble Prediction System for Short-Range Probability Forecasting

Abstract Current operational ensemble prediction systems (EPSs) are designed specifically for medium-range forecasting, but there is also considerable interest in predictability in the short range, particularly for potential severe-weather developments. A possible option is to use a poor man’s ensemble prediction system (PEPS) comprising output from different numerical weather prediction (NWP) centers. By making use of a range of different models and independent analyses, a PEPS provides essentially a random sampling of both the initial condition and model evolution errors. In this paper the authors investigate the ability of a PEPS using up to 14 models from nine operational NWP centers. The ensemble forecasts are verified for a 101-day period and five variables: mean sea level pressure, 500-hPa geopotential height, temperature at 850 hPa, 2-m temperature, and 10-m wind speed. Results are compared with the operational ECMWF EPS, using the ECMWF analysis as the verifying “truth. ” It is shown that, despite.
Perturbations of a rotating black hole. I. Fundamental equations for gravitational, electromagnetic, and neutrino-field perturbations

Decoupled, separable equations describing perturbations of a Kerr black hole are derived. These equations can be used to study black-hole processes involving scalar, electromagnetic, neutrino or gravitational fields. A number of astrophysical applications are made: Misner's idea that gravitational synchrotron radiation might explain Weber's observations is shown to be untenable; rotating black holes are shown to be stable against small perturbations; energy amplification by "superradiant scattering" of waves off a rotating black hole is computed; the "spin down" (loss of angular momentum) of a rotating black hole caused by a stationary non-axisymmetric perturbation is calculated.
System Dynamics and Mechanical Vibrations: An Introduction

1 Theory of Dynamic Systems. - 2 System Representation by Diagrams (Model System). - 3 System Representation by Equations (Mathematical Model). - 4 Transform Analysis Methods of Vibratory Systems (Frequency-response Characteristics). - 5 The Flow of Power and Energy in Systems (Energy Transactions). - Appendix A. - Time-history Curves (Displacement Response and Force Excitation). - Appendix B. - Frequency Response Plots (Normalized Dynamic Compliance and related Characteristics). - Appendix C. - Frequency Response Plots of Power (Normalized Complex Power). - References.
Seasonal overturning variability in the eastern North Atlantic subpolar gyre: a Lagrangian perspective

Abstract. Both observations and ocean reanalyses show a pronounced seasonality in the strength of the Atlantic meridional overturning circulation (MOC) within the eastern North Atlantic subpolar gyre (eSPG). However, attributing this overturning seasonality to seasonal dense water formation remains challenging owing to the wide distribution of recirculation timescales within the Iceland and Irminger basins. Here, we investigate the nature of seasonal overturning variability using Lagrangian water parcel trajectories initialised across the Overturning in the Subpolar North Atlantic Program (OSNAP) East section within an eddy-permitting ocean sea ice hindcast. By adopting a Lagrangian perspective, we show that the seasonal minimum of the Eulerian overturning at OSNAP East in autumn results from a combination of enhanced stratification and increased southward transport within the upper East Greenland Current. This convergence of southward transport within the MOC upper limb is explained by decreasing water parcel recirculation times in the upper Irminger Sea, consistent with a gyre-scale response to seasonal wind forcing. To account for the diversity of recirculation times within the eSPG, we also quantify the Lagrangian overturning (LMOC) as the total dense water formation along water parcel trajectories. The majority of water parcels, sourced from the central and southern branches of the North Atlantic Current, fail to return to OSNAP East prior to experiencing wintertime diapycnal transformation into the lower limb, and thus they determine the mean strength of the LMOC within the eSPG (8.9 ± 2.2 Sv). The strong seasonality of the LMOC is explained by a small collection of upper-limb water parcels, circulating rapidly (≤ 8.5 months) in the upper Irminger and central Iceland basins, whose along-stream transformation is determined by their month of arrival at OSNAP East.
Tuning thermal conductivity of bilayer graphene by inter-layer sp3 bonding: A molecular dynamics study

Using nonequilibrium molecular dynamics simulations, the effect of inter-layer sp3 bonding on the thermal conductivity of bilayer graphene were investigated. Up to 5% fractions of randomly distributed inter-layer sp3 bonds, lead to considerable decreases in the thermal conductivity of bilayer graphene, up to 70%. Phonon power spectrum calculations revealed the strong influence of sp3 inter-layer bonds—compared to weak effect of inter-layer Lennard-Jones interactions—on the thermal transport of the system. These measurements propose the application of the inter-layer sp3 bonding in designing nanoscale devices with tunable thermal conductivities.
Simulation of ISAR Imaging for a Space Target and Reconstruction Under Sparse Sampling via Compressed Sensing

Simulation of inverse synthetic aperture radar (ISAR) imaging of a space target and reconstruction under sparse sampling via compressed sensing (CS) are developed. The numerical bidirectional analytic ray tracing (BART) method is employed to compute the polarized scattering from an electrically large target. With multiorbit and multistation imaging modes, 2-D and 3-D ISAR images are acquired, leading to information retrieval of the space target, such as shape, structure, attitude, etc. CS is introduced into the reconstruction of ISAR images under sparse sampling. As an example, the models of the Aura satellite and the X-37B orbital test vehicle are presented for ISAR imaging and reconstruction.
Infrared Space Observatory Spectroscopy of HH 7-11 Flow and Its Redshifted Counterpart

We have used the two spectrometers on the Infrared Space Observatory to observe the HH 7-11 flow, its redshifted counterpart, and the candidate exciting source SVS 13 in the star formation region NGC 1333. We detect atomic ([O I] 63 μm, [O I] 145 μm, [Si II] 34.8 μm, [C II] 158 μm) and molecular (H2, CO, H2O) lines at various positions along the bipolar flow. Most of the observed lines can be explained in terms of shock-excited emission. In particular, our analysis shows that dissociative (J-type) and nondissociative (C-type) shocks are simultaneously present everywhere along both lobes of the flow. We confirm the low-excitation nature of the Herbig-Haro nebulosities, with shock velocities vs ≲ 40-50 km s-1. Toward both lobes of the outflow, we find preshock densities of n0 ~ 104 cm-3 for both the J and C components, implying B0 ~ 100 μG for B0 ∝ n. In the central region of the flow, close to the exciting source, the preshock density deduced for the C-shock component is n0 ~ 105 cm-3, suggesting a magnetic field ~3 times stronger. We propose that the deficiency of gas-phase water in the post-C-shock regions is caused by freezing onto warm grains processed through the J-shock front and traveling along the magnetic field lines. The total observed cooling from the dissociative shock components is consistent with the power lost by a slow molecular outflow accelerated by a fast neutral HI wind. Finally, the skin of the cloud seen in projection toward the flow appears to be weakly photoionized by BD +30°549, the dominant illuminating source of the NGC 1333 reflection nebula.
An experimental study on disbond detection in a thermal insulation system using guided waves under a load-temperature environment

The integrity monitoring of foam based thermal insulation systems is investigated under a load-temperature environment. Guided wave propagation studies are conducted on two specimens using the pitch-catch approach. To receive only the guided wave, the interval distance is 15mm and 20 mm between two adjacent sensors for specimens. The appropriate guided wave modes are generated by changing the excitation signal. To simulate the thermal and load environment of the thermal insulation system, the test piece is assembled on the load-temperature test machine, where the compression load gradually up to 3 tons is applied to the test piece along its axial direction. Different temperatures are applied to two sides of the test piece. The side without the foam is cooled using Liquid nitrogen to -196°C, while the other side with the foam is heated by the thermocouple to 120 °C. The guided wave signals are obtained before/after the experiment begins/ends, and also received periodically in the joint work process of the pressure and the different temperatures. Signals processing and damage imaging techniques are combined to demonstrate the possible disbond defect. Experimental results show that the disbond defect between the foam and the substrate can be qualitatively detected, and its expansion could be identified.
Local elastic properties of carbon nanotubes in the presence of Stone-Wales defects

Carbon nanotubes are being contemplated as reinforcements for the next generation of composite materials. Stress and strain measures at an atomic scale are required to study the effect of inhomogeneities in nanotube basedstructures. In this work, we have adapted three different stress measures at atomic scales and introduced strain measures as energetically conjugate quantities. These measures are validated for defect free nanotubes and are then used to study the mechanics of 5-7-7-5 topological defects in various single wall nanotubes. It is observed that there is a decrease in the load carrying capacity in the defected region, and this decrease can be attributed to the changes in the kinetics and kinematics in the vicinity of the defects.
Experimental Verification of Real-Time Control for Flexible Systems With On-Off Actuators

A technique for driving a flexible system with on-off actuators is presented and experimentally verified. The control system is designed to move the rigid body of a structure a desired distance without causing residual vibration in the flexible modes. The on-off control actions are described by closed-form functions of the system's natural frequency, damping ratio, actuator force-to-mass ratio, and the desired move distance. Given the closed-form equations, the control sequence can be determined in real time without the need for numerical optimization. Performance measures of the proposed controller such as speed of response, actuator effort, peak transient deflection, and robustness to modeling errors are examined. Experiments performed on a flexible satellite testbed verify the utility of the proposed method.
Blind coding: authentication frauds from the point of view of rate-distortion theory

Abstract Surprisingly, the rate-distortion function appears in a powerful lower bound to the probability of an authentication fraud; we show that the link between authentication theory and rate-distortion theory is not just formal, but also conceptual. To this end we introduce the notion of “blind coding”, that is trying to encode a source output which one cannot observe; we show that authentication frauds can be re-interpreted precisely as trying to blind-code the key source, rather than the clearmessage source. We provide a lower bound to the probability of blind coding, which holds true for any value of the admissible distortion level, at least asymptotically. Seeing authentication frauds as a rate-distortion theoretic problem suggests introducing positive distortion levels in a situation when the authentication of communication is certified only after a sufficiently high number of checks has been successful.
Dynamics of a mixed quantum-classical system at finite temperature

The Davydov model for energy storage and transport in proteins is used to illustrate the problems associated with the thermalisation of mixed quantum-classical systems. A new system of equations of motion is proposed, which leads to the correct statistics and is exact in the adiabatic limit. The dynamics of the semiclassical Davydov model at finite temperature given by the present theory is compared with that obtained by the classical Langevin approach. At biological temperatures, while the classical Langevin dynamics predicts a rapid spread of an initially localised excitation, the semiclassical dynamics predicts a stochastic hopping of a localised excitation and an average localisation 75% at equilibrium.
Image recognition using iterative oblique projection

A new robust method for image recognition based on iterative oblique projection is presented. By oblique projection, both the unstructured and structured noises can be suppressed. To improve recognition accuracy, an iterative process is adopted to reduce interference further. Experiments show that the proposed approach offers better performance than the conventional template matching method.
An efficient implicit mesh‐less method for compressible flow calculations

A dual‐time implicit mesh‐less scheme is presented for calculation of compressible inviscid flow equations. The Taylor series least‐square method is used for approximation of spatial derivatives at each node which leads to a central difference discretization. Several convergence acceleration techniques such as local time stepping, enthalpy damping and residual smoothing are adopted in this approach. The capabilities of the method are demonstrated by flow computations around single and multi‐element airfoils at subsonic, transonic and supersonic flow conditions. Results are presented which indicate good agreements with other reliable finite‐volume results. The computational time is considerably reduced when using the proposed mesh‐less method compared with the explicit mesh‐less and finite‐volume schemes using the same point distributions. Copyright © 2010 John Wiley & Sons, Ltd.
Simulation of Negative Hydrogen Ion Production and Transport

Negative hydrogen ion production by volume process and its transport in a negative hydrogen ion source has been simulated by a combination of three three-dimensional Monte Carlo codes: (1) neutral transport, (2) negative hydrogen ion production, and (3) negative hydrogen ion transport. Neutral transport code has been used to calculate the spatially resolved density spectrum nv of the vibrationally excited H2 molecules. With the negative hydrogen ion production code, the production and distribution of H− ion density n− in the discharge volume has been calculated. And with the negative hydrogen ion transport code, the calculation of the survival probability of H− ions up to the extraction grid has been carried out. In all cases, the experimentally observed plasma parameters, as well as background gas density and temperature profiles, are inputs during trajectory calculation. It has been found that the negative ion density is almost uniform from the ion production zone (driver) to the grid. However, H− ions,.