The world is full of physical interfaces that are inaccessible to blind people, from microwaves and information kiosks thermostats checkout terminals. Blind people cannot independently use such devices without at least first learning their layout, usually only after labeling them with sighted assistance. We introduce VizLens - an accessible mobile application supporting backend can robustly interactively help nearly any interface they encounter. users capture a photo send it multiple crowd...

The increasing number of Internet Things (IoT) objects has been a growing challenge the current spectrum supply. To handle this issue, IoT devices should have cognitive capabilities to access unoccupied portion wideband spectrum. However, most are difficult perform sensing using either conventional Nyquist sampling system or sub-Nyquist since both power-hungry components and intricate hardware unrealistic in power-constrained paradigm. In paper, we propose blind joint scheme by utilizing...

Introducing a data-driven Self-Awareness (SA) module in Cognitive Radio (CR) can support the system to establish secure networks against various attacks from malicious users. Such users manipulate radio spectrum order make CR learn wrong behaviours and take mistaken actions. A basic SA includes ability generative models detect abnormalities inside spectrum. In this work, we propose implement Artificial Intelligence (AI)-based Abnormality Detection techniques at physical (PHY)-layer enabled...

MmWave communication suffers from severe path loss due to high frequency and is sensitive blockages because of penetration loss, especially in mobile scenarios. It highly depends on line-of-sight channels narrow beams, thus efficient beam tracking alignment are necessary techniques maintain robust links, which user mobility lays the foundation for tracking. In this article, ML applied learn mmWave users predict their moving directions. Moreover, article builds up an experiment environment by...

Spectrum sensing is a proactive way in cognitive radio systems to achieve dynamic spectrum access; and compressive (CSS) techniques alleviate the demand for high-speed sampling wideband sensing. Most existing literature discusses Neyman-Pearson channel energy detection threshold adaption schemes an optimal performance of conventional non-compressive scenario. However, CSS, it found that statistics depend not only on noise but also compression ratio, sparsity spectrum, nature recovery...

Compressive sensing (CS) techniques have been proposed for wideband spectrum applications to achieve sub-Nyquist-rate sampling. The complexity of CS recovery algorithm and the detection performance against noise are two main challenges implementation compressive (CSS). Greedy algorithms particular interest in CSS due low complexity. We firstly propose a novel sparsity estimation scheme directly from sub-Nyquist measurements, with which computational effort greedy pursuit can be saved...

A real-time sub-Nyquist wideband spectrum sensing system for millimeter wave (mmWave) implemented on National Instruments mmWave software-defined radio is presented. Based compressed theory and multicoset sampling architecture, the capable of achieving 3.072 $\textGHz $-bandwidth signal at centre frequency 28.5 $. Bayesian sparsity estimation data decimation are applied to realize robust performance reconstruction under dynamic scenarios enable processing, respectively. This paper presents...

The relatively poor atomic-oxygen (AO) resistance of the standard polyimide (PI) films greatly limits wide applications in low earth orbit (LEO) environments. introduction polyhedral oligomeric silsesquioxane (POSS) units into molecular structures PI has been proven to be an effective procedure for enhancing AO films. In current work, a series POSS-substituted poly (pyromellitic anhydride-4,4′-oxydianiline) (PMDA-ODA) (POSS-PI) with different POSS contents were synthesized via...

Equiatomic AlCoCrFeNi high-entropy alloy (HEA) has gained significant interest in recent years because of its excellent mechanical properties. A356 aluminum reinforced by HEA particles was fabricated friction stir processing (FSP) and subsequent heat treatment. Solution aging treatments were specially performed for the composites to control interface microstructure, interfacial microstructure tensile properties explored at different conditions. The between matrix showed a dual-layered...

Wetlands provide important ecosystem services, such as water conservation, biodiversity protection, and carbon sequestration. The Zoige alpine wetland is the largest high-altitude swamp in world plays a critical role regional ecological balance climate change. However, little known about fate of its soil organic (SOC) storage. In this study, we estimated degradation status over past 35 years used machine learning to investigate dynamics driving factors SOC at different depths 1985, 2000,...

Deep learning models struggle to effectively capture data features and make accurate predictions because of the strong non-linear characteristics arbitrage data. Therefore, fully exploit model performance, researchers have focused on network structure hyperparameter selection using various swarm intelligence algorithms for optimization. Sparrow Search Algorithm (SSA), a classic heuristic method that simulates sparrows' foraging anti-predatory behavior, has demonstrated excellent performance...

Channel estimation is crucial to beamforming techniques in directional millimetre wave (mmWave) communications, which generally designed based on channel state information static. However, due the Doppler effect caused by mobility of users, such as unmanned aerial vehicles, high-speed trains and autonomous mmWave changing rapidly. Spatial covariance, defined long-term statistic channels, a promising solution reduce frequency can be used design hybrid precoders. In this paper, we first...

Semi‐alicyclic colorless and transparent polyimide (PI) films with intrinsically flame‐retardant features, excellent optical transparency, good thermal stability have been designed successfully prepared. For this target, an aromatic diamine lateral diphenylphosphine oxide substituent, 2,5‐bis[(4‐aminophenoxy)phenyl]diphenylphosphine (BADPO) was polymerized two alicyclic dianhydrides, including hydrogenated pyromellitic dianhydride (HPMDA) 3,3′,4,4′‐biphenyltetracarboxylic (HBPDA),...

Wholly aromatic polyimide (PI) films with good solution processability, light colors, optical transparency, high storage modulus, and improved heat resistance were prepared characterized. For this purpose, a multi-component copolymerization methodology was performed from fluoro-containing dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), rigid 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), diamine, 2,2'-bis(trifluoromethyl)-4,4'-bis...

To overcome the challenges in high-speed sampling and processing of real-time spectrum measurement, compressive sensing (CS) theory has been implemented wideband sensing. Moreover, to take full advantage CS, nonconvex L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</sub> -norm minimization algorithms are employed reconstruct signals from samples. However, solving these usually leads relatively high computational complexity cost, especially...

Domain adaption is effective for utilizing the knowledge from a source domain to benefit further learning task in different but related target domain. It mainly reduces difference across domains by shared feature representation. So, it also could be taken as transfer algorithm. Besides, another technique, named instance transfer, allows instances reused reweighting. Each method has two facets. Instance must satisfy high similarity between data and data, while ignores of contributions...

A novel and simple HCl-mediated, photocatalytic method for quinoxaline(on)es C3-H arylation with arylhydrazine under transition metal catalyst- oxidant-free conditions is presented. Various underwent this transformation smoothly, demonstrating a broad substrate tolerance providing the corresponding aryl products in moderate to excellent yields. Mechanistic studies indicated that radical pathway may be involved transformation.

In order to explore the casting technology of a high–strength aluminum alloy, effects nickel on solidified microstructure and tensile properties 7075 alloy were studied. alloys without with 0.6% 1.2% prepared by method. The results showed that increase Ni content in increased liquidus temperatures, primary α (Al) grains refined significantly, divorced eutectic structure was gradually formed among preformation Al3Ni phase. comparison, had less intergranular shrinkage porosity, its elongation...

Collaborative compressive spectrum sensing techniques are adopted to achieve reconstruction at sub-Nyquist sampling rate as well improve detection reliability in cognitive radio networks. However, most of the existing research only focuses on sparsity frequency domain. In pursuit achieving further beyond Nyquist and better recovery performance, this paper presents a two- dimensional (2-D) scheme centralized collaborative setting by applying compression both spatial dimensions. To exploit...