118 research outputs found
Multi-bump solutions for a strongly indefinite semilinear Schrodinger equation without symmetry or convexity assumptions
No full textIn this paper, we study the following semilinear Schrodinger equations with periodic coefficient: -Delta u + V(x)u = f(x, u), u is an element of H-1 (R-N). The functional corresponding to this equation possesses strongly indefinite structure. The nonlinear term f(x,t) satisfies some superlinear growth conditions and need not be odd or increasing in t. Using a new variational reduction method and a generalized Morse theory, we proved that this equation has infinitely many geometrically different solutions . Furthermore, if the solutions of this equation under some energy level are isolated, then we can show that this equation has infinitely many m-bump solutions for any positive integer m >= 2. (C) 2007 Elsevier Ltd. All rights reserved.Mathematics, AppliedMathematicsSCI(E)EI0ARTICLE103067-31026
Deep Learning for Detection of Object-Based Forgery in Advanced Video
No full textPassive video forensics has drawn much attention in recent years. However, research on detection of object-based forgery, especially for forged video encoded with advanced codec frameworks, is still a great challenge. In this paper, we propose a deep learning-based approach to detect object-based forgery in the advanced video. The presented deep learning approach utilizes a convolutional neural network (CNN) to automatically extract high-dimension features from the input image patches. Different from the traditional CNN models used in computer vision domain, we let video frames go through three preprocessing layers before being fed into our CNN model. They include a frame absolute difference layer to cut down temporal redundancy between video frames, a max pooling layer to reduce computational complexity of image convolution, and a high-pass filter layer to enhance the residual signal left by video forgery. In addition, an asymmetric data augmentation strategy has been established to get a similar number of positive and negative image patches before the training. The experiments have demonstrated that the proposed CNN-based model with the preprocessing layers has achieved excellent results
One step hydrothermal synthesis of CeO2-ZrO2 nanocomposites and investigation of the morphological evolution
No full textUniform cauliflower-like and rough nano-spheres of CeO2-ZrO2 composites were synthesized by a facile hydrothermal process using only urea as a mineralizer without any surfactant or template. The structural morphologies were found to vary with the reaction time, calcination temperature and dosage of urea and the urea was verified to play an important role in the determination of the CeO2-ZrO2 composite nanostructures. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and other techniques. On the basis of the characterizations, it was proven that there existed migrations or movements during the hydrothermal process especially with long hydrothermal time and a possible mechanism was proposed which would go through a series of procedures of nucleation, Ostwald ripening and Kirkendall effect to account for the structural dynamics and morphological evolutions. Subsequently, the hybrid Ce0.9Zr0.1O2-GO was reduced by a hydrothermal method, which showed good adsorption for RhB.Natural Science Foundation of China (NSFC) [21471103, 21471100, 51002180, 21001074, 20731002, 20871016, 10876002, 91022006, 20973023]; 111 Project [B07012]; Project of Excellent Talents of Beijing [203135407707]; Scientific Research Base Development Program of the Beijing Municipal Commission of EducationSCI(E)[email protected]; [email protected]
Joint Adaptive Coding and Reversible Data Hiding for AMBTC Compressed Images
No full textThis paper proposes a joint coding and reversible data hiding method for absolute moment block truncation coding (AMBTC) compressed images. Existing methods use a predictor to predict the quantization levels of AMBTC codes. Equal-length indicators, secret bits and prediction errors are concatenated to construct the output code stream. However, the quantization levels might not highly correlate with their neighbors for predictive coding, and the use of equal-length indicators might impede the coding efficiency. The proposed method uses reversible integer transform to represent the quantization levels by their means and differences, which is advantageous for predictive coding. Moreover, the prediction errors are better classified into symmetrical encoding cases using the adaptive classification technique. The length of indicators and the bits representing the prediction errors are properly assigned according to the classified results. Experiments show that the proposed method offers the lowest bitrate for a variety of images when compared with the existing state-of-the-art works
Reversible Watermarking Based on Improved Patchwork Algorithm and Symmetric Modulo Operation
No full textThe C-Terminal Arm of the Human Papillomavirus Major Capsid Protein Is Immunogenic and Involved in Virus-Host Interaction
No full textCervical cancer is the second most prevalent malignant tumor among women worldwide. High-risk human papillomaviruses (HPVs) are believed to be the major causative pathogens of mucosal epithelial cancers including cervical cancer. The HPV capsid is made up of 360 copies of major (L1) and 72 copies of minor (L2) capsid proteins. To date, limited high-resolution structural information about the HPV capsid has hindered attempts to understand details concerning the mechanisms by which HPV assembles and infects cells. In this study, we have constructed a pseudo-atomic model of the HPV59 L1-only capsid and demonstrate that the C-terminal armof L1 participates in virus-host interactions. Moreover, when conjugated to a scaffold protein, keyhole limpet hemocyanin (KLH), this arm is immunogenic in vivo. These results provide new insights that will help elucidate HPV biology, and hence pave a way for the design of next-generation HPV vaccines.Chinese government: National Natural Science Foundation [81172885, 81471934, 81371818, 81401669]; National Key Projects in Science and Technology [2012ZX09101316, 2014AA021302]; Fujian Provincial Science Fund [2013J05053]; NIH [R37-GM33050]; University of California San Diego; Agouron FoundationSCI(E)[email protected]; [email protected]
Some existence results for a simplified two fluid system in plasma theory
No full textAbstractIn this paper, we consider a simplified two fluid system in plasma theory. Some multiple existence results for this system are obtained by variational methods and topological degree methods
Local Search with Configuration Checking for SAT
No full textAbstract-Local Search is an appealing method for solving the Boolean Satisfiability problem (SAT). However, this method suffers from the cycling problem which severely limits its power. Recently, a new strategy called configuration checking (CC) was proposed, for handling the cycling problem in local search. The CC strategy was used to improve a state-ofthe- art local search algorithm for Minimum Vertex Cover. In this paper, we propose a novel local search strategy for the satisfiability problem, i.e., the CC strategy for SAT. The CC strategy for SAT takes into account the circumstances of the variables when selecting a variable to flip, where the circumstance of a variable refers to truth values of all its neighboring variables. We then apply it to design a local search algorithm for SAT called SWcc (Smoothed Weighting with Configuration Checking). Experimental results show that the CC strategy for SAT is more efficient than the previous strategy for handling the cycling problem called tabu. Moreover, SWcc significantly outperforms the best local search SAT solver in SAT Competition 2009 called TNM on large random 3-SAT instances.No Full Tex
Local search for Boolean Satisfiability with configuration checking and subscore
No full textThis paper presents and analyzes two new efficient local search strategies for the Boolean Satisfiability (SAT) problem. We start by proposing a local search strategy called configuration checking (CC) for SAT. The CC strategy results in a simple local search algorithm for SAT called Swcc, which shows promising experimental results on random 3-SAT instances, and outperforms TNM, the winner of SAT Competition 2009. However, the CC strategy for SAT is still in a nascent stage, and Swcc cannot yet compete with Sparrow2011, which won SAT Competition 2011 just after Swcc had been designed. The CC strategy seems too strict in that it forbids flipping those variables even with great scores, if they do not satisfy the CC criterion. We improve the CC strategy by adopting an aspiration mechanism, and get a new variable selection heuristic called configuration checking with aspiration (CCA). The CCA heuristic leads to an improved algorithm called Swcca, which exhibits state-of-the-art performance on random 3-SAT instances and crafted ones. The third contribution concerns improving local search algorithms for random k-SAT instances with k>3k>3. Although the SAT community has made great achievements in solving random 3-SAT instances, the progress lags far behind on random k-SAT instances with k>3k>3. This work proposes a new variable property called subscore, which is utilized to break ties in the CCA heuristic when candidate variables for flipping have the same score. The resulting algorithm CCAsubscore is very efficient for solving random k-SAT instances with k>3k>3, and significantly outperforms other state-of-the-art ones. Combining Swcca and CCAsubscore, we obtain a local search SAT solver called CCASat, which was ranked first in the random track of SAT Challenge 2012. Additionally, we perform theoretical analyses on the CC strategy and the subscore property, and show interesting results on these two heuristics. Particularly, our analysis indicates that the CC strategy is more effective for k-SAT with smaller k, while the subscore notion is not suitable for solving random 3-SAT.Full Tex
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