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21.
Khoder Makkawi Nourdine Ait-Tmazirte Maan El Badaoui El Najjar Nazih Moubayed 《Entropy (Basel, Switzerland)》2021,23(4)
When applying a diagnostic technique to complex systems, whose dynamics, constraints, and environment evolve over time, being able to re-evaluate the residuals that are capable of detecting defaults and proposing the most appropriate ones can quickly prove to make sense. For this purpose, the concept of adaptive diagnosis is introduced. In this work, the contributions of information theory are investigated in order to propose a Fault-Tolerant multi-sensor data fusion framework. This work is part of studies proposing an architecture combining a stochastic filter for state estimation with a diagnostic layer with the aim of proposing a safe and accurate state estimation from potentially inconsistent or erroneous sensors measurements. From the design of the residuals, using α-Rényi Divergence (α-RD), to the optimization of the decision threshold, through the establishment of a function that is dedicated to the choice of α at each moment, we detail each step of the proposed automated decision-support framework. We also dwell on: (1) the consequences of the degree of freedom provided by this α parameter and on (2) the application-dictated policy to design the α tuning function playing on the overall performance of the system (detection rate, false alarms, and missed detection rates). Finally, we present a real application case on which this framework has been tested. The problem of multi-sensor localization, integrating sensors whose operating range is variable according to the environment crossed, is a case study to illustrate the contributions of such an approach and show the performance. 相似文献
22.
The optical properties of ethylene vinyl acetate (EVA) film have been studied. The effects of gamma irradiations on the optical spectrum of EVA films have been investigated using spectrophotometric measurements of reflectance and transmittance in the wavelength range 200–1100 nm. The absorption spectra were recorded in the UV–vis region for the unirradiated and irradiated films (from 0 to 50 kGy). Optical constants such as refractive index (n), extinction coefficient (K), and complex dielectric constant have been determined, as well as the optical dispersion parameters and high frequency dielectric constants. A large dependence of the fundamental optical constants on the irradiation dose was noticed. On irradiation, a higher refractive index was obtained as compared with that for unirradiated film. The dispersion parameters, such as E 0 (single‐oscillator energy), E d (dispersive energy), and M ?1 and M ?3 (moments), are discussed in terms of the single‐oscillator Wemple–DiDomenico model. 相似文献
23.
1H-NMR spectrum of tiaprofenic acid in CDCI3 was obtained and proton chemical shifts from tetramethylsilane were assigned to each proton and set of equivalent protons of the molecule. The hydroxy proton of the carboxylic acid group was confirmed by deuterium exchange. The natural abundance C-13 nuclear magnetic resonance spectrum of the compound in CDCI3 was recorded using Fourier transorm technique. The chemical shifts of carbon resonances have been assigned on the basis of the chemical shift additivity theory and the signal multiplicity observed in the single frequency off-resonance decoupled (SFORD) spectrum. Also comparison with carbon chemical shifts of model compounds were useful. 相似文献
24.
A new transparent bulk glass from the system 76TeO2?·?10ZnO?·?9.0PbO?·?1.0PbF2?·?3.0Na2O doped with Er3+ (TZPPN doped with Er3+) has been prepared using the conventional melt-quenching method. Results of differential thermal analysis (DTA) measurements indicate good thermal stability of this glass. The refractive indices at different wavelengths, the optical energy gap, the Sellmeier gap energy and the dispersion energy have been estimated. The Judd–Ofelt parameters, Ω t (t?=?2,?4,?6) of Er3+ were evaluated from optical absorption spectra. Electric dipole, magnetic dipole type transition probabilities, spectroscopic quality factors, branching ratio and radiative lifetimes of several excited states of Er3+ have been predicted using intensity Judd–Ofelt parameters. The spectroscopic properties indicate that TZPPN glass doped with Er3+ is a promising candidate for laser applications and may be suitable for upconversion fibre optical devices. 相似文献
25.
Rachida M’chaar Abdelaziz Sabbar Mouloud El Moudane Noureddine Ouerfelli 《哲学杂志》2020,100(11):1415-1438
ABSTRACT By applying the geometric models and the theoretical equation, the surface tension, the molar volume and the density were studied. The empirical calculations were carried out in temperature range 623?K?≤?T?≤?1123?K. Only few thermophysical properties were estimated for eight quinary alloys: Sn3.55Ag0.5Cu3Bi3Sb, Sn3.48Ag0.5Cu3Bi5Sb, Sn3.48 Ag0.5Cu5Bi3Sb, Sn3.40 Ag0.5Cu5Bi5Sb, Sn3.53Ag1Cu3Bi3Sb, Sn3.46Ag1Cu3Bi5Sb, Sn3.46Ag1Cu5Bi3Sb, Sn3.38Ag1Cu5Bi5Sb. The results show that surface tension and density have a linear appearance for all temperatures. We have also studied the influence of the composition and temperature in the studied alloys. The obtained theoretical results are compared with the experimental ones and with the conventional Pb–Sn welds. 相似文献
26.
Pumped by the 9R(6) 12C16O2 laser lines, CH2F2 produces five SMM emissions. Levels involved in this process are identified with the help of a Fourier transform spectrum. Among these emissions we find cascade and intervibrational transitions allowed by Coriolis resonance between v9 and v3. 相似文献
27.
Waveguide electro-optic modulator in fused silica fabricated by femtosecond laser direct writing and thermal poling 总被引:3,自引:0,他引:3
An integrated electro-optic waveguide modulator is demonstrated in bulk fused silica. A Mach-Zehnder interferometer waveguide structure is fabricated by direct writing with a femtosecond laser followed by thermal poling. A 20 degrees electro-optic phase shift is achieved at an operating wavelength of 1.55 microm with an applied voltage of 400 V and an interaction length of 25.6 mm, which correspond to an estimated effective electro-optic coefficient of 0.17 pm/V for the TE-polarized mode. 相似文献
28.
H. Fitouri R. Boussaha A. Rebey B. El Jani 《Applied Physics A: Materials Science & Processing》2013,112(3):701-710
Bismuth nanodroplets on GaAs substrate were obtained by metalorganic vapor phase epitaxy (MOVPE). New products have been synthesized when Bi nanodroplets are heated under oxygen atmosphere. The oxidation process of Bi nanodroplets consists of a heating from the room temperature to different oxidation temperatures (350, 500, 600 °C) with a temperature rate of 14 °C/min. The annealing duration was fixed to 30 min. The presence of oxygen in the products was confirmed by energy dispersive X-ray (EDX) measurements using a scanning electron microscope (SEM). SEM images show that Bi microcomposites density decrease and their size increases with increasing annealing temperature. After X-ray diffraction analysis of the products no obvious peaks could be observed. The reflectance spectra of the products were studied in spectral domains ranged from 200 nm to 1100 nm. By fitting the reflectivity signal, we extracted the thickness of the products and their refractive index variation versus wavelength. The results show that the thickness of the samples increases with increasing annealing temperature. The photoluminescence (PL) spectra under excitation at 325 nm shows a broad emission centered at around 1.92 eV. 相似文献
29.
K. El Aidoudi A. Qachaou M. Faris H. Lassri A. Fahmi Z. Yamkane 《Optical and Quantum Electronics》2013,45(10):1019-1026
In this work, we present a study of the magneto transport properties in magnetic multilayered structure $\text{ Ni }_{81}\text{ Fe }_{19}\text{/Zr }$ Ni 81 Fe 19 /Zr . The magnetic $(\text{ Ni }_{81}\text{ Fe }_{19})$ ( Ni 81 Fe 19 ) and non magnetic (Zr) layer thickness $(\mathbf{t}_\mathbf{NiFe}, \mathbf{t}_\mathbf{zr})$ ( t NiFe , t zr ) effects on the magneto resistance (MR) are discussed theoretically in the framework of the Johnson–Camley semi classical approach based on the Boltzmann transport equation. A comparison between calculated and measured MR is obtained. The observed MR ratio oscillates for Zr layer thickness with an average period of 7Å. A generally weak $\text{ MR }(\text{ t }_{\mathrm{NiFe}})$ MR ( t NiFe ) ratio for fixed $\mathbf{t}_\mathbf{zr}$ t zr is obtained and it shows a maxima peak of the MR with a value of 1.8 % located at $\mathbf{t}_\mathbf{NiFe}= 80$ t NiFe = 80 Å. 相似文献
30.
An efficient method for preparation of 4,6 or 5,6 disubstituted 3-aminopyridazines was easily carried out starting from easily available 4-bromo-pyridazine-3,6-dione, and using combination of both amination and Pd(0) cross-coupling reactions under microwave irradiation. 相似文献