Article AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

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Enhanced Electrical Networks of Stretchable Conductors with Small Fraction of Carbon Nanotube/Graphene Hybrid Fillers

Carbon nanotubes (CNTs) and graphene are known to be good conductive fillers due to their favorable electrical properties and high aspect ratios and have been investigated for application as stretchable composite conductors. A stretchable Conducting nanocomposite should have a small fraction of conductive filler material to maintain stretchability. Here we demonstrate enhanced electrical networks of nanocomposites via the use of a CNT-graphene hybrid system using a small mass fraction of conductive filler. The CNT-graphene hybrid system exhibits synergistic effects that prevent agglomeration of CNTs and graphene restacking and reduce contact resistance by formation of 1D(CNT)-2D(graphene) interconnection. These effects resulted in nanocomposite materials formed of multiwalled carbon nanotubes (MWCNTs), thermally reduced graphene (TRG'), and polydirnethylsiloxane.(PDMS), which had a higher electrical conductivity compared with MWCNT/PDMS or TRG/PDMS nanocomposites until specific fraction that is sufficient to form electrical network among, conductive fillers. These nanocomposite materials maintained their electrical conductivity when 60% strained.clos

Petrogenesis of the Yeonhwa ultrapotassic intrusions in the Yeongnam Massif-Evidence for enrichment of the Triassic continental lithospheric mantle beneath the Korean peninsula

The Triassic period is when abundant late-orogenic magmatism occurred in the Korean peninsula, but the characteristics of the lithospheric mantle at that time beneath the Yeongnam Massif have not been well-defined because of the scarcity of mafic intrusions. We report zircon U-Pb and phlogopite 40Ar/39Ar ages, petrography, and geochemistry of the Triassic (227.6 Ma) ultrapotassic igneous rocks in the Yeonhwa I Mine (Yeonhwa Ultrapotassic Intrusions, YUI) emplaced into the Taebaeksan Basin in the Yeongnam Massif. The YUI occur as two stocks with different lithologies: phlogopite-rich and amphibole-rich, where the former underwent carbonate melt interaction along the margin in contact with the carbonate formation. The two lithologies share similar compositional and isotopic characteristics; however, the phlogopite-rich YUI better retains its mantle-derived features, having idiomorphic high-Mg# (up to 91.9) phlogopite and diopside phenocrysts and bulk concentrations of high MgO (Mg# = molar 100 Mg/[Mg + Fe] > 70), Cr (208-1150 ppm), and Ni (48-219 ppm). The enrichment of the YUI in H2O (phlogopite-rich), silica contents (50.2-56.9 wt%), and large ion lithophile elements (LILE; K, Rb, Sr, Ba, Pb), together with depletion of high fields strength elements (HFSE; Ti, Zr, Nb, Hf, Ta), are typical of the ultrapotassic rocks in orogenic settings. The elemental and isotopic data imply that the YUI originated from partial melts of the phlogopite-bearing lithospheric mantle near the spinel-garnet transition zone. The extremely enriched isotopic ratios (87Sr/86Sr(t) = 0.70756 to 0.71227, epsilon Nd(t) =-8.82 to-11.0) suggest a highly enriched mantle source, possibly more enriched than the contemporary pelagic sediments. Considering that the Yeongnam Massif was in a subduction system during Permian-Triassic, not a continental collisional belt, the enrichment was inherited from a combination of both young, subduction-related and ancient, pre-existing metasomes in the continental lithospheric mantle. Our data confirm the presence of the enriched, volatile-rich lithospheric mantle beneath the Triassic Yeongnam Massif. This enriched origin contrasts with earlier (c. 240-280 Ma) Yeongnam arc plutons that originated from the depleted asthenospheric mantle (epsilon Nd(t) & GE; +2). Since the enrichment is also characteristic of most of the c. 220-240 Ma igneous rocks around the Korean peninsula, such lithospheric mantle lithology was widespread during the Late Triassic.N

CloudNet: A LiDAR-Based Face Anti-Spoofing Model That Is Robust Against Light Variation

Face anti-spoofing (FAS) is a technology that protects face recognition systems from presentation attacks. The current challenge faced by FAS studies is the difficulty in creating a generalized light variation model. This is because face data are sensitive to light domain. FAS models using only red green blue (RGB) images suffer from poor performance when the training and test datasets have different light variations. To overcome this problem, this study focuses on light detection and ranging (LiDAR) sensors. LiDAR is a time-of-flight depth sensor that is included in the latest mobile devices. It is negligibly affected by light and provides 3D coordinate and depth information of the target. Thus, a model that is resistant to light variations and exhibiting excellent performance can be created. For the experiment, datasets collected with a LiDAR camera are built and CloudNet architectures for RGB, point clouds, and depth are designed. Three protocols are used to confirm the performance of the model according to variations in the light domain. Experimental results indicate that for protocols 2 and 3, CloudNet error rates increase by 0.1340 and 0.1528, whereas the error rates of the RGB model increase by 0.3951 and 0.4111, respectively, as compared with protocol 1. These results demonstrate that the LiDAR-based FAS model with CloudNet has a more generalized performance compared with the RGB model