Aerial road extraction based on an improved Generative Adversarial Network

Aerial photographs and satellite images are one of the resources used for earth observation. In practice, automated detection of roads on aerial images is of significant values for the application such as car navigation, law enforcement, and fire services. In this paper, we present a novel road extraction method from aerial images based on an improved generative adversarial network, which is an end-to-end framework only requiring a few samples for training. Experimental results on the Massachusetts Roads Dataset show that the proposed method provides better performance than several state of the art techniques in terms of detection accuracy, recall, precision and F1-score

SAR Ship Instance Segmentation with Dynamic Key Points Information Enhancement

There  are  several  unresolved  issues  in  the  field  ofship  instance  segmentation  in  synthetic  aperture  radar  (SAR)images.  Firstly,  in  inshore  dense  ship  area,  the  problems  ofmissed  detections  and  mask  overlap  frequently  occur.  Secondly,in   inshore   scenes,   false   alarms   occur   due   to   strong   clutterinterference.  In  order  to  address  these  issues,  we  propose  anovel  ship  instance  segmentation  network  based  on  dynamickey  points  information  enhancement.  In  the  detection  branchof   the   network,   a   dynamic   key   points   module   (DKPM)   isdesigned  to  incorporate  the  target’s  geometric  information  intothe parameters of the dynamic mask head using implicit encodingtechnique.   Additionally,   we   introduce   a   dynamic   key   pointsencoding  branch,  which  encodes  the  target’s  strong  scatteringregions as dynamic key points. It strengthens the network’s abilityto  learn  the  correspondence  between  local  regions  with  strongscattering  and  overall  ship  targets,  effectively  mitigating  maskoverlap issues. Moreover, it enhances the discriminative ability ofnetwork between ship targets and clutter interference, leading toa reduction in false alarm rates. To further enhance the dynamickey  points  information,  a  instance-wise  attention  map  module(IAMM)  is  designed,  which  decodes  the  key  points  during  themask prediction period, generating instance-wise attention mapsbased  on  two-dimensional  Gaussian  distribution.  This  modulefurther enhances the sensibility of network to specific instances.Simulation experiments conducted on the Polygon SegmentationSAR  Ship  Detection  Dataset  (PSeg-SSDD)  and  High  ResolutionSAR Images Dataset (HRSID) demonstrate the superiority of ourproposed  method  over  other  state-of-the-art  methods  in  inshoreand offshore scenes.</p

BSM-Ether: Bribery Selfish Mining in Blockchain-based Healthcare Systems

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Mechanical properties of 3-D printed polyvinyl alcohol matrix for detection of respiratory pathogens

Polyvinyl alcohol is used to 3D print (fused deposition modelling) sampling matrices for bacterial detection. A specific configuration was designed using Computer-Aided Design software. The mechanical properties of the printed samples were studied using uniaxial tensile testing, and compared to those of the original Polyvinyl alcohol filament, with and without heat treatment. The effects of different factors such as UV treatment, printing speed, infill density and printing direction on the mechanical properties of the printed samples including strength, strain and modulus of elasticity were studied. The results show that the effect of the fused deposition modelling process on the mechanical properties of the printed Polyvinyl alcohol cannot be explained by its exposure to heat. UV treatment reduced the strength, characteristic strains and Young's modulus. It makes Polyvinyl alcohol samples brittle. The effects of printing speed and the infill density on the mechanical properties of printed samples can be no linear. An unexpected relation between printing direction and mechanical properties was demonstrated by the studied specimens that needs further theoretical understanding. There is a huge scatter in strength of PVA samples compared with typical engineering materials, and in the fracture strain of original PVA filament, the 3D printing process can reduce the scatter but only by a limited extent. To summarise, there is a sophisticated relation between printing parameters and the mechanical properties of the printed Polyvinyl alcohol

Chiral covalent organic frameworks: design, synthesis and property

Covalent organic frameworks (COFs) are constructed using reticular chemistry with the building blocks being connected via covalent bonds and have emerged as a new series of porous materials for multitudinous applications. Most COFs reported to date are achiral, and only a small fraction of COFs with chiral nature are reported. This review covers the recent advances in the field of chiral COFs (CCOFs), including their design principles and synthetic strategies, structural studies, and potential applications in asymmetric catalysis, enantioselective separation, and chiral recognition. Finally, we illustrate the remaining challenges and future opportunities in this field

Virulence-associated subtilisin-like proteases that use a novel disulphide-tethered exosite to mediate substrate specificity (3LPA, 3LPC, 3LPD)

<div>Many bacterial pathogens produce extracellular proteases that are involved in the degradation of the host extracellular matrix. Dichelobacter nodosus, which causes ovine footrot, is one such pathogen, Mutagenesis and virulence studies revealed that AprV2, one of three secreted subtilisin-like D. nodosus proteases, is required for virulence. Our work challenges the previous hypothesis that the elastase activity of AprV2 is important for disease progression, since aprV2 mutants were virulent when complemented with a variant with impaired elastase activity. These data reveal that an unusual extended disulphide-tethered loop functions as an exosite that governs the ability of AprV2 to degrade insoluble extracellular matrix components. The disulphide bond and Tyr92, located at the exposed end of the loop, were functionally important. Bioinformatics suggests that other pathogens utilize a similar mechanism, providing a new paradigm for understanding the role of proteases in disease.</div><div><br></div><p></p