Miracle-dz/UniFAR-FTUs huggingface dataset:
Optimal design of adaptive tracking controllers for nonlinear systems

We pose and solve an "inverse optimal" adaptive tracking problem for nonlinear systems with unknown parameters. A controller is said to be inverse optimal when it minimizes a meaningful cost functional that incorporates integral penalty on the tracking error state and the control, as well as a terminal penalty on the parameter estimation error. The basis of our method is an adaptive tracking control Lyapunov function whose existence guarantees the solvability of the inverse optimal problem. The controllers designed in this paper are not of certainty-equivalence type. Even in the linear case they would not be a result of solving a Riccati equation for a given value of the parameter estimate. Our abandoning of the CE approach is motivated by the fact that, in general, this approach does not lead to optimality of the controller with respect to the overall plant-estimator system, even though both the estimator and the controller may be optimal as separate entities. Our controllers, instead, compensate for the effect of parameter adaptation transients in order to achieve optimality of the overall system. We combine inverse optimality with backstepping to design a new class of adaptive controllers for strict-feedback systems. These controllers solve a problem left open in the previous adaptive backstepping designs-getting transient performance bounds that include an estimate of control effort.
CRITICAL CASIMIR FORCES BETWEEN SPHERICAL PARTICLES IN FLUIDS

Long-ranged correlations in a ﬂuid close to its critical point (cid:84) (cid:99) cause distinct forces between immersed colloidal particles and the container walls. We calculate such a force and its temperature dependence for the generic case of a spherical particle located at a distance (cid:68) from a planar wall and ﬁnd that the force attains a maximum at a temperature (cid:84) (cid:109)(cid:97)(cid:120) (cid:115) (cid:68) (cid:100) above (cid:84) (cid:99) , which facilitates quantitative experimental tests. The corresponding effective pair interaction between the colloidal particles themselves, potentially leading to aggregation, is also discussed. [S0031-9007(98)06900-2]
Clustering Financial Time Series by Network Community Analysis

In this paper, we describe a method for clustering financial time series which is based on community analysis, a recently developed approach for partitioning the nodes of a network (graph). A network with N nodes is associated to the set of N time series. The weight of the link (i, j), which quantifies the similarity between the two corresponding time series, is defined according to a metric based on symbolic time series analysis, which has recently proved effective in the context of financial time series. Then, searching for network communities allows one to identify groups of nodes (and then time series) with strong similarity. A quantitative assessment of the significance of the obtained partition is also provided. The method is applied to two distinct case-studies concerning the US and Italy Stock Exchange, respectively. In the US case, the stability of the partitions over time is also thoroughly investigated. The results favorably compare with those obtained with the standard tools typically used for clustering financial time series, such as the minimal spanning tree and the hierarchical tree.
Subharmonic Instabilities and Defects in a Granular Layer under Vertical Vibrations

We report an experimental study of subharmonic instabilities observed in a horizontal layer of glass spheres under vertical vibrations. Above a critical value of the acceleration, the layer undergoes a period-doubling instability. When the acceleration is increased further, the spatially homogeneous temporal oscillation at half the excitation frequency becomes unstable and a regular pattern of defects is generated. Each defect separates two regions oscillating out of phase, and is thus connected with the discrete broken symmetry at the period-doubling bifurcation.
Magnetic field dependence of exciton linewidth in quantum wells made of semimagnetic semiconductors: comparison of theory and experiment

This paper presents the result of theoretical and experimental studies of the magnetic field dependence of the exciton linewidth in Cd1−yMgyTe/Cd1−xMnxTe/Cd1−yMgyTe quantum wells. The reflection spectra from the structures with various values of x were measured at T = 2 K in magnetic fields up to 3.5 T applied parallel to the structure’s growth axis. In the theoretical studies, the fluctuations of both concentration and spin projection of magnetic ions have been considered as the main reasons for the exciton line broadening. It is shown that the experimentally observed broadening of the σ− exciton line and the narrowing of the σ+ exciton line with increasing magnetic field are in good agreement with theoretical calculations.
A Survey of Functional Laws of the Iterated Logarithm for Self-Similar Processes

A process X(t) is self-similar with index H > 0 if the finite-dimensional distributions of X(at) are identical to those of aHX(t) for all a > 0. Consider self-similar processes X(t) that are Gaussian or that can be represented throught Wiener-Ito integrals. The paper surveys functional laws of the iterated logarithm for such processes X(t) and for sequences whose normalized sums coverage weakly to X(t). The goal is to motivate the results by including outline of proofs and by highlighting relationships between the various assumptions. The paper starts with a general discussion fo functional laws of the iterated logarithm, states some of their formulations and sketches the reproducing kernal Hilbert space set-up.
Unpreamplified heterodyne detection of 10Gb/s NRZ-OOK with high receiver sensitivity

We report -31 dBm receiver sensitivity for heterodyne detection of 10 Gb/s OOK without using an optical pre-amplifier. These are the highest receiver sensitivities for unpreamplified heterodyne 10 Gb/s detection. We also show the development of a coherent heterodyne balanced fiber optic receiver. The receiver incorporates a DFB or a solid state laser local oscillator, balanced PIN photodiodes, RF post amplifier, automatic frequency control (AFC), phase locked loop (PLL), polarization control, and precision power supplies in a small instrument case. We will show shot noise limited detection of amplitude modulated signals, cancellation of laser RIN noise, performance improvement using balanced detection at 2.5 and 10 Gb/s, and IF linewidth reduction.
VHF radar measurements of small-scale and meso-scale dynamical processes in the middle atmosphere

The principle of VHF radar observations of the atmosphere is briefly summarized. Gravity-wave and turbulence sources, as seen by VHF radar, are described, followed by an outline of observations of upward-propagating gravity waves and the corresponding transport of energy and momentum. Frequency and wavenumber spectra are discussed in terms of a universal spectrum of waves and quasi-two-dimensional turbulence. The divergence of vertical flux of horizontal momentum, which indicates the interaction of waves with the mean wind, is considered. Saturation of gravity waves often occurs in the middle atmosphere where it can cause turbulence. This controls the vertical transport of passive tracers by means of turbulent diffusion. These phenomena are investigated by VHF radars, particularly in the mesosphere. The phenomenology of ‘turbulence echoes' from the mesosphere, influenced considerably by the electron density profile, is examined. The generation mechanisms of turbulence and its coexistence with stable stratifications are explored. The presented model offers an explanation of the different features of the observed radar echoes and provides a better understanding of the interaction of meso-scale and small-scale phenomena of waves and turbulence in the middle atmosphere. Finally, a summary of some remaining questions that could be solved by further collaborative efforts, including the application of radars, is given.
XL. The electrical double layer at the interface of two liquids

Summary The potential function at the interface of two liquid phases about which a small amount of electrolyte is distributed is considered. The total potential drop D, due to the circumstance that one phase contains an excess of positive ions and the other an equal excess of negative ions, is divided up into two parts, occurring on both sides of the interface, the size of which is governed by (n = ionic concentrations, K=dielectric constants) and Fig. 1 shows a typical potential curve, fig. 2 the corresponding charge curve, for small values of D. The largest part of the potential drop occurs in the phase where the product nK has the smallest value. For the general case that a differs appreciably from one practically the whole potential drop occurs in one phase, provided D is not very large. This does not necessarily imply that the rates of decay of the charge density on both sides of the interface are very different. For larger values of D the partition of the potential drop about both phases becomes les.
The effects of two temporal cues on pitch judgments

A series of experiments required listeners to judge which of two sequentially presented pulse trains, bandpass filtered to contain only unresolved harmonics, had the higher pitch. The effects of two temporal cues were explored. The “common interval” cue refers to the fact that the interval between any two pulses in each train is an integer multiple of 1/F0, where F0 is the period of the pulse train. The “mean rate” cue arises from the fact that the number of pulses in any period of time is proportional to F0. It was manipulated, independently of the common interval cue, by removing a proportion of the pulses in each of two trains with different F0s. The mean rate cue was removed in one condition of the experiments by deleting more pulses in the stimulus with the higher F0; in other conditions, the number of pulses deleted was either independent of F0, or was higher for the stimulus with the lower F0. The results both of forced-choice and of pitch-matching experiments showed that pitch judgments were affec.
Accurate and quantitative phase retrieval methods for a series of defocused images with application to in-line Gabor microscopy

In 1948, Gabor proposed a lens-less in-line holographic microscope where the recorded hologram is a result of interference of both reference wave and the wave diffracted from the object. In this work, an analysis of the hologram formation and sampling issues are presented using the local-spatial frequency distribution at the camera plane. Techniques are presented that enable the reconstruction of the complex object wave at the camera plane from a series of defocused images. It is suggested to use the band-limited angular spectrum method for the back-propagation of the field components, so that an accurate and quantitative estimate of the object-wave at the object plane is obtained. The reconstruction procedure does not rely on the paraxial approximation and is therefore applicable to the case of high NA beams.
Thermal Floorplan Base on Conjugate Gradient Solver in HotSpot

In this paper, we introduce an effective iterative method to solve the thermal linear system in HotSpot thermal floorplan, the iterative Conjugate Gradient Method is suitable to solve the traditional sparse matrix linear equations. We define a class of dummy sparse linear systems in iterative thermal floorplan algorithm, the iterative methods for linear system can be extended to apply to other iterative framework algorithm. We apply the conjugate gradient method to solve the thermal model in floorplan of VLSI physical design. The experiments' result shows that thermal floorplan using Conjugate gradient method is effective. The running time of our incremental conjugate gradient thermal solver with Jocabi Precondition is approximate 0.59 comparing with LU decomposition method.
Combining two strategies to optimize biometric decisions against spoofing attacks

Spoof attack by replicating biometric traits represents a real threat to an automatic biometric verification/ authentication system. This is because the system, originally designed to distinguish between genuine users from impostors, simply cannot distinguish between a replicated biometric sample (replica) from a live sample. An effective solution is to obtain some measures that can indicate whether or not a biometric trait has been tempered with, e.g., liveness detection measures. These measures are referred to as evidence of spoofing or anti-spoofing measures. In order to make the final accept/rejection decision, a straightforward solution to define two thresholds: one for the anti-spoofing measure, and another for the verification score. We compared two variants of a method that relies on applying two thresholds – one to the verification (matching) score and another to the anti-spoofing measure. Our experiments carried out using a signature database as well as by simulation show that both the brute-force and its probabilistic variant turn out to be optimal under different operating conditions.
Dynamics of a Projectile Penetrating Sand. Part II

Additional data are reported that confirm a theory presented in a previous paper for the penetration of a stable flat‐nosed projectile in sand. The negative acceleration of the projectile can be expressed by the relations: −dv/dt=αv2, v0>v>vc; −dv/dt=βv2+γ, vc>v>0 where the coefficients α, β, γ are positive constants and v0 is the striking velocity. In the case where air is removed from the sand and the sand is loaded transverse to the trajectory by one atmosphere pressure, the coefficients α and β are characteristic of inelastic and elastic impact, respectively, where the flow process is regarded as Newtonian. An additional experiment has been performed where quartz powder produced by impact is plotted as a function of initial projectile energy. Although the powder production curve can be represented roughly as a straight line through the origin, there are small discontinuities in slope corresponding to the critical velocity v=vc. The velocity of sound in sand has been measured under the conditions of th.
Cholesky decomposition of a hyper inverse Wishart matrix

The canonical parameter of a covariance selection model is the inverse covariance matrix Σ -1 whose zero pattern gives the conditional independence structure characterising the model. In this paper we consider the upper triangular matrix Φ obtained by the Cholesky decomposition Σ - 1 = Φ T Φ. This provides an interesting alternative parameterisation of decomposable models since its upper triangle has the same zero structure as Σ -1 and its elements have an interpretation as parameters of certain conditional distributions. For a distribution for Σ, the strong hyper-Markov property is shown to be characterised by the mutual independence of the rows of Φ. This is further used to generalise to the hyper inverse Wishart distribution some well-known properties of the inverse Wishart distribution. In particular we show that a hyper inverse Wishart matrix can be decomposed into independent normal and chi-squared random variables, and we describe a family of transformations under which the family of hyper inverse Wishart distributions is closed.
Heterojunction formation using amorphous materials

Heterojunctions have been fabricated by depositing glass films onto single−crystal silicon substrates. Junction behavior has been exhibited regardless of the electrical or chemical properties of the glass film. The observed characteristics are a function of these properties. Current rectification, variable capacitance, sharp reverse breakdown, and photovoltaic responses have been observed.
Camera calibration using time-coded planar patterns

In this paper a novel pattern design for camera calibration using planar patterns with the Zhang calibration method is presented. In contrast to other work related to this calibration technique, which deals with the design and extraction of spatial image features, our focus lies on the precise and fully automated extraction of corresponding points by temporal image features using a sequence of planar patterns, which are displayed by a flat screen. The extraction of correspondences in our approach does not utilize areal properties of the images and therefore is hardly influenced by projective distortion, image distortion, or inhomogeneous illumination. Furthermore, not the whole pattern but only parts of it need to be visible in an individual view. In addition, the planarity as well as the physical precision of the control points of the pattern are ensured by the very nature of the flat screen. The overall calibration time may be reduced, as no human interaction is necessary. We compare the results gained from this novel temporal pattern design with those gained from commonly used checkerboard patterns. The proposed approach resulted in an increased precision for the calibration.
CT image processing for hardwood log inspection

This study explores the application of digital image processing techniques to a machine vision system for log inspection in the forest products industry. This machine vision system uses the computerized tomography (CT) imaging to locate and identify internal defects in hardwood logs. To apply CT to these industrial vision problems requires efficient and robust image processing methods. Several image processing techniques are addressed in this paper: adaptive image smoothing, multi-threshold-based segmentation, morphological filtering, and 3-D connectiveness labeling. Experimental results of these image processing techniques with CT images from two different wood species demonstrate the efficacy of the inspection system.
Temperature dependence of MOS devices

To study the temperature dependence of MOS devices, the temperature at which the capacitance-voltage characteristics were measured, was varied as a parameter. Transition from high to low type C–U characteristics was observed at 92 °C (test signal 1 kHz). This temperature was found to be dependent on measurement frequency. Surface state density was calculated and found to be 4.4 × 1011 cm−2 per unit area per eV. The dependence of the transition frequency on temperature is plotted. Um die Temperaturabhangigkeit von MOS-Bauelementen zu untersuchen, wurde die Temperatur, bei der die Kapazitats-Spannungscharakteristiken gemessen werden, als Parameter variiert. Ubergange vom„high-Typ”-zur “low-Typ”-C–U-Charakteristik wurden bei 92 °C (Prufsignal 1 kHz) beobachtet. Es wurde gefunden, das diese Temperatur von der Mesfrequenz abhangt. Die Oberflachenzustandsdichte wurde zu 4,4 × 1011 cm−2 pro Einheitsflache pro eV berechnet und die Abhangigkeit der Ubergangsfrequenz von der Temperatur aufgezeichnet.
Detecting changes in the ar parameters of a nonstationary arma process

We present a method for detecting changes in the AR parameters of an ARMA process with arbitrarily time varying MA parameters. Assuming that a collection of observations and a set of nominal time invariant AR parameters are given, we test if the observations are generated by the nominal AR parameters or by a different set of time invariant AR parameters. The detection method is derived by using a local asymptotic approach and it is based on an estimation procedure which was shown to be consistent under nonstationarities.
Magnetic field sensing with a single piezoelectric ceramic disk: Experiments and modeling

This study reports on the magnetoelectric coupling in a single piezoelectric ceramic disk subjected to both ac and dc magnetic fields perpendicularly applied to the sample’s plane. Eddy currents are induced within the electrodes of the ceramic by ac magnetic flux via the Lenz–Faraday equation and yields Lorentz forces and stresses which are transferred to the piezoelectric ceramic. This latter transduces stress into electrical charges through electromechanical coupling in radial mode. The measured output magnetoelectric current could be successfully modeled using piezoelectric equations providing the inductively coupled voltage between the electrodes of the ceramic is taken into account. This voltage originates from the ac magnetic flux through the experimental loop, which is not a perfect short-circuit and yields two other contributions to the total current: piezoelectric current due to the induced electric field and the dielectric loop current. Radial velocity measurements confirmed the distinct contrib.
PERIOD DISTRIBUTIONS OF IRREGULARITY VARIABLE RR LYR STARS.

The occurrence of irregularly variable RR Lyrae stars in four globular clusters and the Draco dwarf spheroidal galaxy are examined in order to determine their period distributions. Two of the clusters are of Oosterhoff type I, M3 and M5, and two are of Oosterhoff type II, M15 and omega-Cen. Draco does not fit into either Oosterhoff group, having a medium ab-type period of 0.611 days, but few C-type variables. Irregular variability is more frequent among the shorter period ab-type RR Lyraes (P less than 0.65 days) and, at least in M15 and omega-Cen, among the longer period c-type variables. These period distributions are consistent with some mode-mixing explanations for irregular variability. It is suggested that the Blazhko effect in ab-type RR Lyraes is a nonlinear mixture of the fundamental and third overtone radial pulsation modes (Borkowski, 1980). This accounts for the occurrence of irregular ab-variables only at shorter periods, but yields RR Lyrae star masses larger than those predicted by stellar evolution theory.
QUASI-EXACTLY-SOLVABLE QUANTAL PROBLEMS: ONE-DIMENSIONAL ANALOGUE OF RATIONAL CONFORMAL FIELD THEORIES

The class of quasi-exactly-solvable problems in ordinary quantum mechanics discovered recently shows remarkable parallels with rational two-dimensional conformal field theories. This fact suggests that investigation of the quasi-exactly-solvable models may shed light on rational conformal field theories. We discuss a relation between these two theoretical schemes and propose a mathematical formulation for the procedure of constructing quasi-exactly solvable systems. This discussion leads us to a kind of generalization of the Sugawara construction.
Induced L2‐norm control for LPV systems with bounded parameter variation rates

A linear, finite-dimensional plant, with state-space parameter dependence, is controlled using a parameter-dependent controller. The parameters whose values are in a compact set, are known in real time. Their rates of variation are bounded and known in real time also. The goal of control is to stabilize the parameter-dependent closed-loop system, and provide disturbance/error attenuation as measured in induced L2 norm. Our approach uses a bounding technique based on a parameter-dependent Lyapunov function, and then solves the control synthesis problem by reformulating the existence conditions into a semi-infinite dimensional convex optimization. We propose finite dimensional approximations to get sufficient conditions for successful controller design.
Batch input to a multiserver queue with constant service times

Delay probability formulas for batch input to a finite number of constant-holding-time servers are derived under the assumption of statistical equilibrium. The service-delay distribution (delay until a first request from the batch enters service) is given in terms of the roots of a transcendental equation, while the probability of no service-delay and the average delay are expressed directly in terms of the number of servers, the holding time, and the parameters of the input process. A numerical example with a fixed batch size is discussed.