PA-iMFL: Communication-Efficient Privacy Amplification Method against Data Reconstruction Attack in Improved Multi-Layer Federated Learning

Recently, big data has seen explosive growth in the Internet of Things (IoT). Multi-layer FL (MFL) based on cloud-edge-end architecture can promote model training efficiency and model accuracy while preserving IoT data privacy. This paper considers an improved MFL, where edge layer devices own private data and can join the training process. iMFL can improve edge resource utilization and also alleviate the strict requirement of end devices, but suffers from the issues of Data Reconstruction Attack (DRA) and unacceptable communication overhead. This paper aims to address these issues with iMFL. We propose a Privacy Amplification scheme on iMFL (PA-iMFL). Differing from standard MFL, we design privacy operations in end and edge devices after local training, including three sequential components, local differential privacy with Laplace mechanism, privacy amplification subsample, and gradient sign reset. Benefitting from privacy operations, PA-iMFL reduces communication overhead and achieves privacy-preserving. Extensive results demonstrate that against State-Of-The-Art (SOTA) DRAs, PA-iMFL can effectively mitigate private data leakage and reach the same level of protection capability as the SOTA defense model. Moreover, due to adopting privacy operations in edge devices, PA-iMFL promotes up to 2.8 times communication efficiency than the SOTA compression method without compromising model accuracy.Comment: 12 pages, 11 figure

Bionic titania coating carbon multi-layer material derived from natural leaf and its superior photocatalytic performance

Bionic titania coating carbon multi-layer material was fabricated by employing canna leaves as substrate and carbon precursor. Titania nanocrystals were assembled and coated on the natural films. The carbonation treatment under pure N2 atmosphere yielded the ultrathin multi-film hybrid material. The carbon layer was coated with small anatase titania crystallite (8â10 nm) and possessed a highly specific surface area of 248.3 m2 gâ1. Examination using UVâvisible spectrophotometer (UVâvis) showed that the band gap of the multi-layer material was reduced to 2.75 eV, and the hydrogen production by photocatalytic splitting of water under visible light irradiation was about 302 μmol gâ1 after six hour. Keywords: Bionic multi-layer, Titania, Carbon, Photocatalytic performanc

Village energy survey reveals missing rural raw coal in northern China: Significance in science and policy

Burning coal for winter heating has been considered a major contributor to northern China's winter haze, with the district heating boilers holding the balance. However a decade of intensive efforts on district heating boilers brought few improvements to northern China's winter air quality, arousing a speculation that the household heating stoves mainly in rural area rather than the district heating boilers mainly in urban area dominate coal emissions in winter. This implies an extreme underestimation of rural household coal consumption by the China Energy Statistical Yearbooks (CESYs), although direct evidence supporting this speculation is lacking. A village energy survey campaign was launched to gather the firsthand information on household coal consumption in the rural areas of two cities, Baoding (in Hebei province) and Beijing (the capital of China). The survey data show that the rural raw coal consumption in Baoding (5.04 x 10(3) kt) was approximately 6.5 times the value listed in the official CESY 2013 and exceeded the rural total of whole Hebei Province (4668 kt), revealing a huge amount of raw coal missing from the current statistical system. More importantly, rural emissions of particulate matter (PM) and SO2 from raw coal, which had never been included in widely distributing environmental statistical reports, were found higher than those from industrial and urban household sectors in the two cities in 2013, which highlights the importance of rural coal burning in creating northern China's heavy haze and helps to explain why a number of modeling predictions on ambient pollutant concentrations based on normal emission inventories were more bias-prone in winter season than in other seasons. We therefore recommend placing greater emphasis on the "missing" rural raw coal to help China in its long-term ambition to achieve clean air in the context of rapid economic development. (C) 2017 Elsevier Ltd. All rights reserved

Bone analysis using an aggregation‐induced emission‐active iridium complex

Abstract Fluorescent analysis of bone provides valuable insights into bone structures. However, conventional dyes suffer from low specificity on bone tissue, small stokes shift, short fluorescent lifetime, and aggregation‐caused quenching effect, which result in low efficacy and artifacts. In this work, we design an aggregation‐induced emission (AIE)‐active iridium(III) complex (Ir‐BP2) as a highly selective, convenient, nondestructiveness, and dual‐mode staining agent for bone analysis. Ir‐BP2 containing phosphonate groups selectively binds to hydroxyapatites, the main component of bone matrix, and exhibits turn‐on AIE phosphorescence with prolonged lifetime. Ir‐BP2 exhibits promising biosafety and offers higher accuracy in staining calcium deposits than conventional Alizarin Red S staining assay when it is employed in real‐time monitoring of osteogenesis differentiation process. A ready‐to‐use staining spray of Ir‐BP2 is fabricated. By using fluorescent imaging and lifetime imaging, Ir‐BP2 staining provides valuable insights into bone microstructure analysis, microdamage diagnosis, and bone growth state identification. Further, Ir‐BP2 is successfully applied on a human spine vertebra for diagnosing bone invasiveness of eosinophilic granuloma, validating its clinical practice. This work presents a powerful tool in bone analysis and will lead to new approaches for the diagnosis and treatment of bone‐related diseases

Ultrafast Broadband Photodetectors Based on Three-Dimensional Dirac Semimetal Cd₃As₂

Photodetection with extreme performances in terms of ultrafast response time, broad detection wavelength range, and high sensitivity has a wide range of optoelectronic and photonic applications, such as optical communications, interconnects, imaging, and remote sensing. Graphene, a typical two-dimensional Dirac semimetal, has shown excellent potential toward a high-performance photodetector with high operation speed, broadband response, and efficient carrier multiplications benefiting from its linear dispersion band structure with a high carrier mobility and zero bandgap. As the three-dimensional analogues of graphene, Dirac semimetal Cd₃As₂ processes all advantages of graphene as a photosensitive material but potentially has stronger interaction with light as a bulk material and thus enhanced responsivity. In this work, we report the realization of an ultrafast broadband photodetector based on Cd₃As₂. The prototype metal–Cd₃As₂–metal photodetector exhibits a responsivity of 5.9 mA/W with a response time of about 6.9 ps without any special device optimization. Broadband responses from 532 nm to 10.6 μm are achieved with a potential detection range extendable to far-infrared and terahertz. Systematical studies indicate that the photothermoelectric effect plays an important role in photocurrent generation. Our results suggest this emerging class of exotic quantum materials can be harnessed for photodetection with a high sensitivity and high speed (∼145 GHz) over a broad wavelength range