Miracle-dz/UniFAR-FTUs huggingface dataset:
H∞ Control Synthesis for Lurie Networked Control Systems with Multiple Delays Based on the Non‐Uniform Characteristic

This paper investigates the H ∞ control synthesis problem for Lurie networked control systems (NCSs) with multiple time‐varying delays. With the consideration of both network‐induced delays and data packet dropout, Lurie NCSs discussed in this work can effectively be transformed into Lurie control systems with multiple time‐varying delays. In addition, with the non‐uniform distribution characteristics of network delays, based on the delay probability distribution, the stable controller design, and H ∞ synthesis, approaches are derived in the form of linear matrix inequalities (LMIs). Finally, a set of numerical examples are studied, and the results demonstrate the applicability and effectiveness of the suggested approaches.
Dynamical behavior of spots in a nonequilibrium distributive active medium

Numerical studies of a two-dimensional active medium with long-range inhibition and additional global inhibition far from equilibrium, show a bifurcation sequence from stationary spots to elliptically oscillating spots, followed by a transition to traveling spots. General properties of the spot dynamics and their dependence on the applied boundary conditions, as well as on the global inhibition are discussed.
How to use a nanowire to measure vibrational frequencies: Device simulator results

Here we present a theoretical investigation of double well nanowire device that will be studied experimentally over a range of temperatures. Our nanowires are made from InAs with three InP barriers between which lie two InAs quantum wells. These wells have associated with them sharp electronic states between which electrons can tunnel. In the absence of a bias, resonant transmission of electrons is possible; but on applying a bias the levels in neighboring wells acquire different energies, thereby frustrating transmission. If the offset in energy is matched by the frequency of a phonon within the device that couples to the electrons in the wells then there will be a rise in current. We present here the results of simple device simulator calculations, on the basis of which the dimensions of an optimized device are determined.
ON A LOCALISED SINGLE-VALUED EXTENSION PROPERTY

In this article, we investigate, a certain localised version of the single-valued extension property for a bounded linear operator on a Banach space. We show that this condition behaves canonically under the Riesz functional calculus, and derive a number of characterisations in terms of kernel-type and range-type spaces for the operator and its adjoint. The theory is exemplified in the case of isometries, analytic Toeplitz operators, invertible composition operators on Hardy spaces, and weighted shifts.
Robustness properties of mean-variance portfolios

In recent years, new ideas for the robustification of the traditional mean-variance frontier have appeared in the literature. One of these approaches is based upon the robust counterpart idea, introduced by Ben-Tal and Nemirovski. To make this idea work in practice, realistic uncertainty sets have to be specified. In this article, we are investigating two popular uncertainty sets together with their impact on the efficient frontier. As a main contribution we will provide two theorems stating that the corresponding robust efficient frontiers are identical to the classical efficient frontier up to some risk level. This especially implies that the classical efficient portfolios are already robust themselves. We will briefly discuss the relevance of this finding for practical applications.
Application of alternative multidisciplinary optimization formulations to a model problem for static aeroelasticity

Abstract A new model problem for static aeroelasticity is introduced and used to illustrate several alternative approaches for formulating multidisciplinary design optimization problems. The alternatives are distinguished by the kind of analysis problem feasibility that is maintained at each optimization iteration. In the familiar "multidisciplinary feasible" approach, the full multidisciplinary analysis problem is solved at each iteration of the optimizer. At the other end of the spectrum is the "all-at-once" approach where none of the individual analysis discipline equations is guaranteed to be satisfied until optimization convergence. In between lie other possibilities that amount to enforcing feasibility of the individual analysis disciplines at each optimization iteration, but allowing the coupling between the disciplines to be incorrect until optimization convergence. Results are given for these three approaches applied to the new model. In general, delaying feasibility until optimality reduces the total amount of computing work.
Approximations of boundary crossing probabilities for a Brownian motion

Using the Girsanov transformation we derive estimates for the accuracy of piecewise approximations for one-sided and two-sided boundary crossing probabilities. We demonstrate that piecewise linear approximations can be calculated using repeated numerical integration. As an illustrative example we consider the case of one-sided and two-sided square-root boundaries for which we also present analytical representations in a form of infinite power series.
The H I distribution in clouds within galaxies

An interpretation is given for the relatively flat distribution of atomic hydrogen as a function of radius within the visible disks of spiral galaxies and the existence of a correlation between H I surface density and morphological class of spiral galaxy. The H I is mostly contained in constant column density envelopes of molecular clouds. The clouds have a two-dimensional filling factor of unity when a galaxy is viewed face on. The column density of the cloud envelopes depends on the ratio of flux of H2 dissociating radiation in the ambient medium to envelope gas density. The flat H I profiles imply the gas density and pressure follow the ultraviolet ambient flux on kiloparsec scales throughout a given galaxy. Later-type galaxies have larger ultraviolet surface brightnesses, as deduced from the H-alpha surface brightnesses. Therefore, thicker protective H I envelopes develop in late-type spirals. 49 references.
Cycle-by-cycle estimation of cylinder pressure and indicated torque waveform using crankshaft speed fluctuations

In this work, frequency response functions (FRFs) are used for estimation of cycle-by-cycle cylinder pressure and indicated torque waveform, using crankshaft speed fluctuations. The FRFs are mapped as a function of the discrete Fourier transform of engine speed, mean speed and manifold pressure using a multilayer neural network. The accuracy of the model is analysed using some of the parameters derived from the cylinder pressure. These include the indicated mean effective pressure and peak pressure. The load torque on the engine is also estimated using a closed-loop observer. The model is tested on a test rig consisting of single-cylinder engine coupled with an eddy current dynamometer. The results show that the model is suitable for the estimation of cylinder pressure and other variables related to it at the operating points where the cyclic variations are within a driveability limit.
An improved algorithm for steiner trees

Two basic results for the Euclidean Steiner minimal tree problem are shown: (1) all admissible partitions of the set of nodes (which the tree should span) correspond to degenerate full Steiner topologies, and can be systematically derived from these topologies if degeneracy occurs; (2) for any given full Steiner tree topology there exists a lower bound on the value of the corresponding Steiner tree (this bound holds as an equality if the tree is full). Taken together these two results suggest a relatively efficient (although still exponential) branch and bound algorithm for the Steiner minimal tree construction. The algorithm uses the lower bound to discard some topologies after a brief check, and does away with the need to check all the possible partitions of the node set.
Almost inductive limit automorphisms and embeddings into AF-algebras

Abstract The crossed product of an AF-algebra by an automorphism, a power of which is approximately inner, is shown to be embeddable into an AF-algebra. The proof uses almost inductive limit automorphisms, i.e. automorphisms possessing a sequence of almost invariant finite-dimensional C*-subalgebras converging to the given AF-algebra.
Influence of Thermodynamic Nonequilibrium on the Acoustic Properties of Gases

This paper is a brief review of results of experimental and theoretical studies in the field of acoustics of nonequilibrium gas-plasma media. New acoustical properties of nonequilibrium media caused by the change in sign of the second viscosity and the dispersion coefficients are considered. Such media are acoustically active. Conditions are discussed for generating new nonlinear acoustical structures.
The simple branching process: a note on convergence when the mean is infinite

Let denote the simple branching process with Z 0 = 1 and let G denote the distribution function of Z 1 . Suppose G satisfies x −α−γ(x)≦1 − G(x) ≦ x −α+γ(x) for large x, where (i) 0 < α < 1, (ii) γ (x) is non-negative and non-increasing, (iii) xγ (x) is non-decreasing and (iv) Then lim n→∞ α n log (Zn + 1) converges almost surely to a non-degenerate finite random variable W satisfying P(W = 0) = q = probability of extinction of the process.
SAW Convolver Employing Unidirectional Transducers for Improved Efficiency

During the past few years much work has been directed at the development of high performance SAW convolvers. All of the devices so far reported have employed conventional bidirectional transducers to excite the SAW and have accepted the inherent 6 dB losses associated with this form of acoustic generation. presented for convolvers with unidirectional transducers based on the multistrip coupler and threephase technologies. These convolvers had a centre frequency 300 MHz, bandwidths of 15-40% and high convolution efficiency -70 to -54 dBm. The threephase convolver displayed the additional attribute of variable bandwidth. In the optimum device self convolution suppression was better than 45 dB. In all of the devices only a single stage fabrication was required. In this paper results are
On the role of Ta cap in the recrystallization process of CoFeB layers

To understand the role of Ta capping on the tunneling magnetoresistance of CoFeB/MgO/CoFeB tunnel junctions, we performed an atom probe study on model CoFeB/Ta junctions. In as-prepared state, CoFeB exhibits chemically and structurally homogeneous amorphous structure. The nanoanalysis demonstrates that B segregation to the Ta cap enforces crystallization to start at the opposite interface towards the MgO barrier and so warrants the correct orientation relation. Carrying out isothermal and isochronal heat treatments, the diffusion coefficient of Boron in amorphous CoFeB could be determined.
Long-Term Evolution of Rotational States and Nongravitational Effects for Halley-like Cometary Nuclei

Abstract We present the results of numerical simulations for the long-term evolution of rotational states of near-prolate cometary nuclei over many orbits under sublimation-induced torques. We derive plausible evolutionary paths for the rotational states and show that they strongly depend on the location of active areas on the nucleus. We conclude that for acceptable locations of active regions on the nucleus, the rotational state of the nucleus maintains nearly constant precessional angles and nongravitational forces over many orbits as suggested by observations of Comet P/Halley. In these cases, the strongest active area should be near cometographic midlatitudes when the equatorial plane is defined to contain the intermediate and small axes of inertia. A Halley-like nucleus with active areas and a near-commensurability (≈2) of precessional and rotational periods and an assumed density near 0.4 g cm-3 is capable of maintaining a consistent 4.1-day delay in the perihelion passage for each apparition as observations suggest. However, the exact amount of delay (or advance) depends on the precise details of the rotational state, including the direction of the rotational angular momentum vector, the details of the active areas such as locations, tilts, and strengths, the secular water production curve, and the mass (or density) of the nucleus. We predict a spin-up of the nucleus provided that the same set of active areas are present over many orbits. This spin-up is presumably the major cause for nuclear splittings.
Toeplitz Forms And Their Applications

Part I: Toeplitz Forms: Preliminaries Orthogonal polynomials. Algebraic properties Orthogonal polynomials. Limit properties The trigonometric moment problem Eigenvalues of Toeplitz forms Generalizations and analogs of Toeplitz forms Further generalizations Certain matrices and integral equations of the Toeplitz type Part II: Applications of Toeplitz Forms: Applications to analytic functions Applications to probability theory Applications to statistics Appendix: Notes and references Bibliography Index.
Semigroups in Which each Ideal is a Retract

A non-empty subset I of a semigroup S is called an ideal if ab, ba ∈ I whenever a ∈I, b∈S. A subset R of S will be called a retract if there exsists a retraction of S onto R, that is a homomorphism of S onto R which leaves each element of R fixed. The purpose of this paper is to study semigroups in which every ideal is a retract. For convenience we shall call such semigroups retractable. Such semigroups seem to arise naturally; for example, it is easy to show that if the lattice of congruence relations on S is a complemented lattice then S is retractable.
A NEW MODIFIED-RATE APPROACH FOR GAS–GRAIN CHEMISTRY: COMPARISON WITH A UNIFIED LARGE-SCALE MONTE CARLO SIMULATION

We compare the results of the unified Monte Carlo chemical model with the new modified-rate equation (MRE) method under a wide range of interstellar conditions, using a full gas–grain chemical network. In most of the explored parameter space, the new MRE method reproduces very well the results of the exact approach. Small disagreements between the methods may be remedied by the use of a more complete surface chemistry network, appropriate to the full range of temperatures employed here.
A symptotic formulae relating to the physical theory of crystals

In the physical theory of crystals great formal difficulties are encountered when the exact shape of the crystal is to be taken into account. Certain methods of approximation have therefore been developed and successfully used by several authors. However, as the validity of these methods was recently questioned by Sir C. V. Raman, a more rigorous examination of the problem had to be undertaken. It is found that the old procedure is fully justified provided the number of boundary particles is small compared with the total number of particles in the crystal. In particular, it is shown that lattice sums may in general be replaced by the corresponding infinite series, and that the distribution of frequencies follows with sufficient accuracy Bom’s law for cyclic crystals. Upper bounds are obtained for the errors caused by these approximations.
Renewal-type equations for a general repair process

We consider a component which undergoes instantaneous general repairs on failure. Suppose that V i = Φ(V i-l + Y i ), where V i is the virtual age immediately after the ith failure, Y i is the time between the (i - 1)th and ith failures, Φ(.) is a specified repair functional, and V 0 =s. We derive integral equations for the repair density, and also for the joint density of repairs with respect to chronological age and virtual age on failure. In the asymptotic case, approximations are obtained for the mean and variance of virtual age on failure, virtual age after repair, and time between failures. Two policies are then considered. The first, an upgraded repair strategy employs minimal repairs until the component reaches a specified age, thereafter repairs restore the virtual age to that prescribed level. The second policy considered is the Kijima Type 2 model which is not amenable to the usual g-renewal analysis that is used in the Type 1 model. The repair density is obtained by numerical solution of the relevant integral equation. Finally, approximations for the asymptotic moments are found to be in close agreement with simulated results.
The L shell region of importance for waves emitted at ground level as a loss mechanism for trapped electrons > 68 keV

The objective of this paper is to identify the L shell region(s) where VLF waves emitted at ground level may play a significant role as a loss mechanism for radiation belt electrons with energies above 68 keV. This assessment is made possible by studying the day-night differences in inner belt electron precipitation and comparing with the much stronger transmission of waves at frequencies of 15--25 kHz through the ionosphere at night and the known higher daytime intensities for waves of natural origin other than lighting. Intensities of electrons trapped on drill shells which dip below sea level in the anomaly are used to study the rates of loss from the radiation belts. In 1979 the inner radiation belt was shown to have had the following unique features for electrons >68 keV: (1) the rates of precipitation from the radiation belts at longitudes west of 140/sup 0/E were significantly greater near midnight than near noontime for Lroughly-equal(1.6-2.2); (2) at Lroughly-equal1.75 the nighttime rates of injection showed little correlation with the precipitation on other L shells, in contrast with the daytime precipitation in which a significant correlation existed with the precipitation rates throughout the range L = 1.2-5.0. From these empirical findingsmore » one concludes that in the heart of the inner radiation belt at longitudes west of 140/sup 0/E, lightning and/or transmitter-generated VLF waves emitted from ground level probably played a significant role in precipitating electrons >68 keV at nighttime. Below the region L = 1.6 and above L = 2.2 the observed diurnal variations were much less pronounced, indicting that VLF waves emitted at ground level in this frequency range were not the major source of precipitation. « less
Correlated cyanogen and sodium anomalies in the globular clusters 47 Tuc and NGC 6752

Spectroscopic analyses have been made of echelle plates of pairs of CN-strong and CN-weak giants in the globular clusters 47 Tuc and NGC 6752. Our differential analysis reveals that in NGC 6752 sodium and aluminum are enhanced in the CN-strong stars by approximately 0.5 dex and 0.2 dex, respectively. All other elements studied (Mg, Si, Ca, Fe, and Ba) appear to have identical abundances in the two groups of stars. In 47 Tuc, only sodium shows any enhancement (by approx.0.4 dex) in the CN-strong stars.
Atmospheric Lapse Rate Regimes and Their Parameterization

Abstract Lapse rates, moist adiabatic lapse rates and the critical lapse rate for baroclinic adjustment are calculated and compared for the mean annual, January and July states in the Northern Hemisphere. In the troposphere above the planetary boundary layer zonal mean lapse rates are within 20% of the moist adiabatic lapse rate from the equator up to about 30°N in January and 50°N in July, but are appreciably more stable in higher latitudes. The latitudinal distribution of tropospheric mean lapse rates clearly delineates two regimes in the atmosphere—a low-latitude regime where the lapse rates are essentially moist adiabatic, and a high-latitude regime where the lapse rates are essentially the critical lapse rate for baroclinic adjustment. The dividing point between the two regimes shifts from 28°N in January to 47°N in July, and the transition is less sharp in July than in January. The absence of appreciable seasonal changes in lapse rates in midlatitudes can be attributed to counterbalancing seasonal c.
Theoretical investigation of the dependence of double beta decay tracks in a Ge detector on particle and nuclear physics parameters and separation from gamma ray events

The sizes of tracks of events of neutrinoless double-beta decay in a Germanium detector depend on particle physics and nuclear physics parameters such as neutrino mass, right-handed current parameters, etc., and nuclear matrix elements. In this paper for the first time Monte Carlo simulations of neutrino-accompanied ($2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) and neutrinoless double-beta decay ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) events, and of various kinds of background processes such as multiple and other $\ensuremath{\gamma}$ interactions are reported for a Ge detector. The time history of the evolution of the individual events is followed and the sizes of the events (partial volumes in the detector inside which the energy of the event is released) are investigated. Effects of the angular correlations of the two electrons in $\ensuremath{\beta}\ensuremath{\beta}$ decay, which again depend on the above nuclear and (for $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ decay) on particle physics parameters, are taken into account and have been calculated for this purpose for the first time on basis of the experimental half-life of $^{76}\mathrm{G}\mathrm{e}$ and of realistic nuclear matrix elements. The sizes determine, together with the location of the events in the detector, the pulse shapes to be observed. It is shown for $\ensuremath{\beta}\ensuremath{\beta}$ decay of $^{76}\mathrm{G}\mathrm{e}$, that $\ensuremath{\beta}\ensuremath{\beta}$ events should be selectable with high efficiency by rejecting large size (high multiplicity) $\ensuremath{\gamma}$ events. Double-escape peaks of similar energy of $\ensuremath{\gamma}$ lines show concerning their sizes similar behavior as $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ events, and in that sense can be of some use for corresponding 'calibration' of pulse shapes of the detector. The possibility to distinguish $\ensuremath{\beta}\ensuremath{\beta}$ events from $\ensuremath{\gamma}$ events is found to be essentially independent of the particle physics parameters of the $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ process. A brief outlook is given on the potential of future experiments with respect to determination of the particle physics parameters $⟨{m}_{\ensuremath{\nu}}⟩,⟨\ensuremath{\lambda}⟩,⟨\ensuremath{\eta}⟩$.
Intermediate Model Solutions to the Lorenz Equations: Strange Attractors and Other Phenomena

Abstract The low-order, nine-component, primitive equation model of Lorenz (1980) is used as the basis for a comparative study of the quality of several intermediate models. All the models are intermediate between the primitive equations and quasi-geostrophy and will not support gravity-wave oscillations; this reduces to three the number of independent components in each. Strange attractors, stable limit cycles, and stable and unstable fixed points are found in the models. They are used to make a quantitative intercomparison of model performance as the forcing strength, or equivalently the Rossby number, is varied. The models can be ranked from best to worst at small Rossby number as follows: the primitive equations, the balance equations, hypogeostrophy, geostrophic momentum approximation, the linear balance equations, and quasi-geostrophy. At intermediate Rossby number the only change in this ranking is the demotion of hypogeostrophy to the position of worst. Caveats about the low-order model, and hence.