Nanjing University of Information Science and Technology

About: Nanjing University of Information Science and Technology is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Precipitation & Aerosol. The organization has 14129 authors who have published 17985 publications receiving 267578 citations. The organization is also known as: Nan Xin Da.

Effective and Efficient Image Copy Detection with Resistance to Arbitrary Rotation

Abstract: For detecting the image copies of a given original image generated by arbitrary rotation, the existing image copy detection methods can not simultaneously achieve desirable performances in the aspects of both accuracy and efficiency. To address this challenge, a novel effective and efficient image copy detection method is proposed based on two global features extracted from rotation invariant partitions. Firstly, candidate images are preprocessed by an averaging operation to suppress noise. Secondly, the rotation invariant partitions of the preprocessed images are constructed based on pixel intensity orders. Thirdly, two global features are extracted from these partitions by utilizing image gradient magnitudes and orientations, respectively. Finally, the extracted features of images are compared to implement copy detection. Promising experimental results demonstrate our proposed method can effectively and efficiently resist rotations with arbitrary degrees. Furthermore, the performances of the proposed method are also desirable for resisting other typical copy attacks, such as flipping, rescaling, illumination and contrast change, as well as Gaussian noising. key words: image copy detection, copy attacks, arbitrary rotation, rotation invariant, intensity orders

Delay-Slope-Dependent Stability Results of Recurrent Neural Networks

Abstract: By using the fact that the neuron activation functions are sector bounded and nondecreasing, this brief presents a new method, named the delay-slope-dependent method, for stability analysis of a class of recurrent neural networks with time-varying delays. This method includes more information on the slope of neuron activation functions and fewer matrix variables in the constructed Lyapunov-Krasovskii functional. Then some improved delay-dependent stability criteria with less computational burden and conservatism are obtained. Numerical examples are given to illustrate the effectiveness and the benefits of the proposed method.

Ti3C2Tx MXene-Activated Fast Gelation of Stretchable and Self-Healing Hydrogels: A Molecular Approach.

Abstract: MXene-based hydrogels, a flourishing family of soft materials, have recently emerged as promising candidates for stretchable electronics. Despite recent progress, most works use MXenes as conductive nanofillers. Herein, by tuning the molecular interactions between MXene nanosheets and other constituents within the hydrogels, we demonstrate Ti3C3Tx MXene can act as a versatile cross-linker to activate the fast gelation of a wide range of hydrogels, starting from various monomer- and polymer-based precursors. The gelation behavior varies significantly across hydrogels. In general, the fast gelation mechanism is attributed to the easier generation of free radicals with the help of Ti3C2Tx MXene and the presence of multiscale molecular interactions between MXene and polymers. The use of MXene as a dynamic cross-linker leads to superior mechanical properties, adhesion, and self-healing ability. Owing to the inherent photothermal behavior of Ti3C3Tx and the heterogeneous phase-transforming features of polymers, a polymer-MXene hydrogel is demonstrated to exhibit distinctive thermosensation-based actuation upon near-infrared illumination, accompanied by rapid shape transformation.

Influence of boreal summer intraseasonal oscillation on rainfall extremes in southern China

Abstract: How boreal summer intraseasonal oscillation (BSISO) modulates the probability and spatial distributions of extreme rainfall occurrence over populous southern China was examined, using the newly proposed BSISO indices and two high-resolution rain-gauge-based rainfall datasets in China. The probability density function of May–August rainfall in southern China is skewed towards large values in phases 2–4 of the first component and in phases 5–7 of the second component of BSISO life cycle, during which the probability of extreme rainfall events at the 75th (90th) percentile increases by 30–50% (over 60%) relative to the non-BSISO period. The devastating floods with prolonged extreme rainfall in southern China over the three past decades occurred coincidently with these BSISO phases. The first component of BSISO, associated with 30–60-day eastward/northeastward-propagating ISO, is more favourable for the rainfall extreme over in-land China. In contrast, the second component of BSISO, related to the 10–30-day northwestward propagating ISO, tends to link with the rainfall extreme along the southeast coast of South China. Moisture budget indicates that the favourable environment for rainfall extreme is associated with southwesterly moisture convergence over southern China, while the moisture advection contributes insignificantly. This study suggests a potential for monitoring and probabilistic prediction of extreme rainfall events in southern China based on the real-time BSISO indices.