New extreme-point robust stability results for discrete-time polynomials

This paper provides some new extreme-point robust-stability results for discrete-time polynomials with special uncertainties in the coefficient space. The proofs, obtained using the barycentric coordinates, are simple and the results specialize to existing robust-stability results

Constructive function approximation: theory and practice

In this paper we study the theoretical limits of finite constructive convex approximations of a given function in a Hilbert space using elements taken from a reduced subset. We also investigate the trade-off between the global error and the partial error during the iterations of the solution. These results are then specialized to constructive function approximation using sigmoidal neural networks. The emphasis then shifts to the implementation issues associated with the problem of achieving given approximation errors when using a finite number of nodes and a finite data set for training

Bounding the frequency response for digital transfer functions: results and applications

This paper introduces robust stability techniques for the computation of exact bounds for the frequency response of FIR and IIR digital filters in which the l∞ norm of the coefficients is bounded

Output Stabilizability

In this report, we provide algebraic tests to determine whether a linear Single-Input-Single-Output (SISO) system, is stabilizable with a constant output feedback

Neural networks in fault detection: a case study

We study the applications of neural nets in the area of fault detection in real vibrational data. The study is one of the first to include a large set of real vibrational data and to illustrate the potential as well as the limitations of neural networks for fault detection

Feasibility analysis of channel equalizers using Kharitonov-type results

Necessary and sufficient conditions for determining the robust location of the roots of a family of polynomials are presented. This family appears when multipath fading channels are considered due to the uncertainty in the channel impulse response. The uncertainty is reflected by means of confidence intervals for the channel parameters. A feasibility analysis of digital equalizers is performed in the frequency domain to determine whether the poles are to be found in a prespecified region of the complex plane. The resulting tests, which can be carried out in a graphical manner, are both analysis and design tools, which can help to decide the suitable length of a constrained equalizer. The analysis method presented resolves the location of the poles on a zero-forcing equalizer structure

El Virus del mosaico común del poroto (BCMV), raza tipo, patógeno limitante para algunos cultivares en Cruz del Eje (Cba.)

Bean Common Mosaic Virus (BCM V ), Type strain, was identified according to host range (only Phaseolus sp, L was infected); simptoms; dilution end point (DEP) 1O - 10-4; termal inactivation point (T.I.P.) 55-604C; viri6n normal length 747 nm. Seed trasmition was estimated in 86%, and Myzus persi. cae Sulz trasmited the virus in a non persistent way. On epidermal strips amorphous inclusion were observed. Host range, TIP, DEP, and seed transmitiou were considered for race determination. The disease had tremendous importance. During 1975 and 1976 was cause of the loss of 55 and 35 has. respectivily of the c.v. Bolita Cristad in the samo field. During 1976 and 1977 loss was estimated in 12% and 18% respect.vily with thL, c.v. Bolita Común.Se identifica al mosaico común del poroto (CBMV), raza Tipo en base a rango de hospedantes (solo infecta a c.v, de Phaseolus sp.); síntomas; a que su P.D.F. se determinó entre 10-3 y 10-4; el P.I.T. entre 55-609C y el largo normal del virión en 747 nm; a que lo trasmitió Myzus persicae Sulz, en forma no persistente; que su trasmisión por semilla resultó del 86% y que se observaron inclusiones amorfas en epidermis. La raza se determinó en base a hospedantes diferenciales teniéndose en cuenta además el P.D.F.; P.I.T. y el porcentaje de trasmisión por semilla de las distintas razas. La enfermedad motivó el abandono de 55 has., del c.v. Bolita Cristal en 1975 y 35 has. durante 1976 en el mismo predio. En Bolita Común produjo la pérdida de 12% de las plantas en 1976 y el 18% e n 1977. Otros cultivares tipo Jamapa se comportaron como tolerantes

VCAN (versican)

Review on VCAN (versican), with data on DNA, on the protein encoded, and where the gene is implicated

Untangling free carrier and exciton dynamics in layered hybrid perovskites using ultrafast optical and terahertz spectroscopy

\ua9 2024 The Author(s). Published by IOP Publishing Ltd.Layered hybrid perovskites (LPKs) are promising as alternatives or additives to 3D metal halide perovskites for optoelectronic applications including photovoltaic cells, LEDs and lasers due to their increased stability. However, high exciton binding energies in these materials mean that excitons are the majority species under the operating conditions of many devices. Although the efficiency of devices that incorporate LPKs has been increasing, much is still unknown about the interplay of excitons and free charge-carriers in these materials, which is vital information for understanding how optoelectronic properties dictate device efficiency. In this work, we employ optical pump/THz probe spectroscopy (OPTP) and visible transient absorption spectroscopy (TAS) to analyse the optoelectronic properties and charge-carrier dynamics of phenylethylammonium lead iodide (PEA)2PbI4. By combining these techniques, we are able to disentangle the contributions from excitons and free charge-carriers. We observe fast cooling of free charge-carriers and exciton formation on a timescale of ∼400 fs followed by slower bimolecular recombination of residual free charge-carriers with a rate constant k 2 ∼ 109 cm3s−1. Excitons recombine via two monomolecular processes with lifetimes t 1 ∼ 11 ps and t2 ∼ 83 ps. Furthermore, we detect signatures of exciton-phonon coupling in the transient absorption kinetic traces. These findings provide new insight into the interplay between free charge-carriers and excitons as well as a possible mechanism to further understand the charge-carrier dynamics in LPKs

Few-mode metal-free perovskite optical fiber with second-order optical nonlinearity

Semiconductor core optical fibers are highly desirable for fiber-based photonic and optoelectronic applications as they can combine strong optical nonlinearities, tight light confinement, wide transmission bands, and electronic functionality within a single platform. Perovskites have emerged as particularly exciting materials for semiconductor photonics as they have strong optical nonlinearities and tunable optoelectronic bandgaps. However, lead-based perovskites contain toxic elements and are, therefore, not environmentally friendly. Furthermore, in fiber form, their core-size is prohibitively large, making them unsuitable for nonlinear optics and applications that require single-mode guidance, such as telecommunications. Here, we report a metal-free perovskite core optical fiber where lead has been substituted for an ammonium cation in the perovskite structure. The core material has a wide bandgap greater than 5 eV, a high laser damage threshold, and a core diameter that can be produced as small as 5 \ub5m. At this core size, the fiber supports just six modes, and the fundamental mode can readily be excited and isolated. Moreover, the metal-free perovskite has a second-order susceptibility that is absent in the archetypal lead-based perovskites and many other semiconductor core materials, such as silicon and germanium. The second-order susceptibility is important for many nonlinear optics applications, such as second-harmonic generation and quantum optics