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Providing the actual Promise of Sendai Framework with regard to Devastation Threat Reduction in Delicate and also Conflict-Affected Contexts (FCAC): An instance Study in the NGO GOAL's Reply to the actual Syria Conflict.
The dynamism envisioned in future high-capacity gridless optical networks requires facing several challenges in distortion mitigation, such as the mitigation of interchannel interference (ICI) effects in any optical channel without information of their adjacent channels. Machine learning (ML)-based techniques have been proposed in recent works to estimate and mitigate different optical impairments with promising results. We propose and evaluate two training strategies for supervised learning algorithms with the aim to minimize ICI effects in a gridless 3×16-Gbaud 16-quadrature amplitude modulation (QAM) Nyquist-wavelength-division multiplexing (WDM) system. One strategy, called updating strategy, is based on symbol training sequence, and the other one, called characterization strategy, is based on an offline training using a previous system characterization. Artificial neural networks (ANN), support vector machine (SVM), K-nearest neighbors (KNN), and extreme learning machine (ELM) algorithms are explored for both training strategies. Experimental results showed a bit error rate (BER) improvement at low training lengths for both training strategies, for instance, gains up to ∼4dB in terms of optical signal-to-noise ratio were achieved in a back-to-back scenario. Besides, the KNN and ELM algorithms showed significant BER reduction in transmission over 250 km optical fiber. Additionally, we carried out a brief computational complexity analysis where ELM presented only 1.9% of ANN processing time. Hence, the use of ML-based techniques could enhance the optical gridless networks performance and consequently fulfill future traffic demands.Classic imaging systems may experience deleterious effects of optical turbulence, leading to their quality degradation induced by image jitter and blur. Using a recently introduced model for the refractive index power spectrum of natural water turbulence accounting for average temperature in the range of 0°-30°C and average salinity concentration in NaCl in the range of 0-40 ppt, we derive expressions for turbulence-induced modulation transfer functions. Our analysis indicates that the imaging systems are very sensitive not only to the variance of fluctuations in these parameters but also to their average values. Our results are essential for underwater optical engineering, providing regional and seasonal variations in optical turbulence.Limited by the conditions and performance of ground-based optical observations, it is difficult for us to obtain a plethora of optical cross section (OCS) data for some space objects (SOs). Unevenly distributed OCS data and unclear labels will affect the performance of SOs recognition based on neural networks. Furthermore, when we need to identify a new SO or SO category using deep neural network, the trained network model may no longer be applicable. We need to retrain the network with new training data. In order to alleviate these problems and improve the generalization and training convergence speed of SOs recognition networks, a novel, to the best of our knowledge, neural network model, ARSRNet, is proposed in this paper. The ARSRNet can identify SOs and their attitude accurately using only a small quantity of training OCS data and without clear labels. And the proposed network is able to adapt to new recognition tasks. Meanwhile, we propose an AdamRprop network optimization algorithm to accelerate network training and improve recognition accuracy. Experimental results show that the recognition accuracy of ARSRNet reaches 90.60% on the test OCS dataset. Compared with mainstream network optimization algorithms, the proposed AdamRprop is more appropriate for ARSRNet and can accelerate the convergence of ARSRNet.We present highly efficient green, yellow, and red filters based on a metal-dielectric structure. The filters encompass only five layers of alternating zinc tin oxide and silver thin films that are grown on soda lime glass and white light-emitting diodes (LEDs) using direct current magnetron sputtering at room temperature. The designed filters provide efficient color filtering in the visible spectrum. High purity colored light is obtained by direct application of filters on LEDs as color converters. The presented method offers an easy way for realizing different colors by tuning the thicknesses of layers in the structure.With the development of laser communication networking, laser-ranging technology is becoming more and more applicable. In this paper, high-accuracy ranging is implemented based on intradyne coherent detection at a communication rate of 1048.576 Mbps. The ranging accuracy is affected by clock phase calculation error and code loop track error. Parallel clock phase difference calculation, frame head correlation, and ranging ambiguity region handle are combined with the ranging calibration method, realizing millimeter-level corrected distance measurement. Dynamic range measurement above 1 m is proven to be continuous through the ranging ambiguity region handle. In addition, high-precision clock frequency deviation between two asynchronous terminals can be obtained through derivation of one-way distance at static ranging or by derivative of distance difference at bidirectional ranging. The methods proposed in this paper are verified by inter-satellite laser-ranging on orbit, and the results are analyzed.The theory of transformation optics is used to adjust the direction of emitted beams from a flat lens. In this paper, a planar lens is presented based on the transformation optics approach, which converts cylindrical beams emitted from a line source into a planar beam at the desired angle. find more The index profile of a planar inhomogeneous lens is considered as the refractive index of the original coordinate system. So, this yields a lens that produces a flat wave at an arbitrary angle. The performance of the structure is confirmed by COMSOL software.We proposed a new scheme of spectroscopic reflectometry (SR) that improves the stability with respect to the intensity variations of the incident light and simplifies the measurement procedure. The proposed method enables this by simultaneously measuring the incident light and the reflected light. Using the multi-order retarder, we modulate the incident light intensity into a high-frequency signal at the spectral domain. Even though the spectrometer measures the sum of reflected light and modulated incident light, each signal can be separately obtained using the Fourier transform. The proposed method is verified through the measurement of SiO2 thin film on the Si substrate with various incident light intensities.In this paper, a design scheme of an automobile low-beam light illumination system with a reflector free-form surface is presented. Per the energy grid mapping theory and edge ray theory, an oblique triangular energy mapping scheme was proposed, and the free-form reflector was obtained by geometric iterative calculation. The Monte Carlo ray tracing method was used to simulate the system. The simulation results met the regulatory requirements of ECE R112, and the light efficiency could reach 81%. The length, width, and height of the reflector were 55.61mm×22.02mm×23.70mm. The reflector achieves a special light type through precise light distribution, does not need other shielding objects, and has the advantage of small size.A Sagnac loop interferometer based on concatenated polarization-maintaining fiber (PMF) tapers is proposed for simultaneous measurement of seawater salinity and temperature. The influences of the distance between the PMF tapers as well as fiber taper diameter on sensor performance have been investigated. Experimental results indicate that the fabricated sensor with a distance of 3 cm between adjacent fiber tapers possesses the salinity and temperature sensitivities of 0.367 nm/% and -0.728nm/∘C, respectively, and the taper waist diameter of 20 µm would help to improve salinity sensitivity in comparison with a sensor of 30 µm in diameter. The proposed Sagnac loop interferometer based on concatenated PMF tapers is expected to find potential applications in the measurement of seawater salinity.In terms of the shortcomings of defect detection based on the electroluminescence of conventional silicon solar panels, which can only be performed under darkroom conditions, a defect detection system that can work under the Sun with any irradiance in all weather is designed. The system electrifies solar panels through a modulated current source, uses high frame rate InGaAs area array detectors for image data acquisition, and transmits images via CameraLink. Using these image data as data sources, a defect display algorithm model is designed. Through experiments, it can effectively collect the defect information of solar panels within the range of 0.2 to 1300W/m2 of sunlight irradiance. Based on this, according to the relationship of the modulated phase difference between the defective points and the nondefective points found in the experiment, an enhancing algorithm for image saliency is proposed. The results show that this algorithm can reduce background interference in an effective way and improve the contrast of defects displayed under high irradiance.All inorganic perovskite materials have drawn extensive attention, owing to their outstanding performance, facile solution-processed method, and potential applications in optoelectronic devices. However, uncontrollable morphology, high defect density, and instability of perovskites prepared via solution-processed method are the main challenges for their large-scale production and commercialization. Herein, we prepared large-scale CsPbBr3 microwire arrays with highly ordered morphology and high crystalline quality by a template-assisted method. The photodetectors based on CsPbBr3 microwire arrays exhibited remarkable on/off photocurrent ratio of 9.02×103, high detectivity of 1.59×1013 Jones, high responsivity of 4.55 A/W, and fast response speed of 4.9/3 ms. More importantly, the photocurrent of the photodetectors hardly changed in air after being stored for two months, indicating remarkable stability. This study demonstrates that CsPbBr3 microwire arrays provide the possibility for preparing large-scale and high-performance optoelectronic devices.This paper presents the bidirectional confocal measurement of a microsphere, which enables the simple measurement of the sphere with a similar number of measuring points taken on its upper and its lower hemispheres. The innovative measuring strategy is the placement of the sphere above a mirror and the subsequent measurement of the upper hemisphere on the real sphere and the lower hemisphere on the mirrored sphere. While theoretical explanations are given first, the main focus of the paper is the presentation of the idea itself and the very promising empirical findings. We believe these findings prove that the measuring strategy presented has the potential to become a prime method for the optical characterization of microspheres.We present a numerical study of the structured light produced by a laser beam transmitted by a symmetric pyramidal prism. From the Fresnel diffraction formulation, we obtain expressions for the amplitudes valid for an arbitrary number of prism faces, and for both acute and flat-topped prisms. The expressions are readily evaluated numerically and are a significant advancement over the restrictive plane wave models used in prior work. We consider applications in optical trapping and give examples in which the intensity distributions contain a number of bright spots having similar power, as is suitable for the simultaneous trapping of several particles. We also consider applications in lithography and, under other conditions, obtain results in which uniform periodic intensity patterns are produced. Advantages of employing pyramidal prisms in such applications are their excellent stability and their efficiency in the production of structured light.
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