摘要：
Multifractal theory has been widely used in different kinds of fields. In this paper, methods were proposed to extract two kinds of multifractal descriptors of gray series and two-dimensional surfaces for gray image based on the multifractal detrended fluctuation analysis. The proposed multifractal parameters can be well described by texture feature through the test of some textures. Three aspects of experiments have been conducted to verify the robustness of the proposed parameters, which include noise immunity, degree of image blurring and compression ratio. Comparisons were conducted between the proposed parameters and other kinds of texture feature parameters calculated by the standard multifractal analysis, the method of differential box counting and the methods of gray level co-occurrence matrix. Results demonstrate that the proposed exponents of H(2) and h(2) have great noise immunity and are robust to image compression and blurring.
期刊：
Journal of Applied Science and Engineering,2014年17(1):81-92 ISSN：1560-6686
通讯作者：
Wang, G.-J.(csgjwang@csu.edu.cn)
作者机构：
[Zhou, Wei; Wang, Guo-Jun; Xu, Yang] School of Information Science and Engineering, Central South University, Changsha 410083, China;[Zhou, Wei] College of Information Science and Technology, Hunan Agriculture University, Changsha 410128, China
通讯机构：
School of Information Science and Engineering, Central South University, China
关键词：
Chinese remainder theorem;Key management;Multi-privileged group communications;Multiway tree
摘要：
Key management becomes more difficult in multi-privileged communications due to the dynamic membership and the complex relations between users and resources. In this paper, we propose a novel key management scheme in which the key graph is based on multiway trees. Chinese remainder theorem is employed to combine some encrypted rekeying materials into a short message for rekeying. As a result, users can update affected keys through the rekeying material and one-way function by themselves. The security analysis shows forward and backward security can be maintained. Compared with some existing schemes, our proposed scheme can reduce rekeying overhead efficiently.
关键词：
Optical color image encryption;Phase truncation operation;The position multiplexing
摘要：
We propose an optical color image cryptosystem based on position multiplexing technique and phase truncation operation. Compared with the reported color image encryption method, we employ the position multiplexing technique to encrypt the color image in only one spatial channel. Meanwhile, our proposed method can maintain the nonlinear characteristic of the cryptosystem and avoid various types of the currently existing attacks, especially the iterative attack. Simulation results are presented to demonstrate the security and robustness performance of the proposed method.
会议名称：
3rd International Conference on Photonics and Image in Agriculture Engineering (PIAGENG) - Image Processing and Photonics for Agricultural Engineering
摘要：
In view of virtual plant has practical demands on quality, image and degree of realism animation in growing process of plant, this thesis design the animation based on mechanism and regularity of plant growth, and propose the design method based on 3D MAX technology. After repeated analysis and testing, it is concluded that there are modeling, rendering, animation fabrication and other key technologies in the animation design process. Based on this, designers can subdivid the animation into seed germination animation, plant growth prophase animation, catagen animation, later animation and blossom animation. This paper compounds the animation of these five stages by VP window to realize the completed 3D animation. Experimental result shows that the animation can realized rapid, visual and realistic simulatation the plant growth process.
关键词：
Auto-correlation;Power time series;Multifractal detrended analysis;Multifractal detrended cross-correlation analysis;Time-delay
摘要：
Multifractal theory has been widely used in kinds of field. In this paper, methods were proposed to study in the power-law auto-correlation and cross-correlation of power operating data based on multifractal detrended analysis (MF-DFA) and multifractal detrended cross-correlation analysis (MF-DXA). We find that both the price and the load time series in California power market and PJM power market exhibit long-term correlation. And the cross-correlation behaviors of the two series in each power market and between the two markets are also analyzed by the method MF-DXA after testing the existence of the cross-correlation of the above power operating data. However, there are some differences in the cross-correlation behaviors between the two markets. It shows that the cross-correlation of the price and the load is significant in every time periods in California 1999 power market, but in the year of 2000 in the same region market, the cross-correlation is insignificant in most time periods. Meanwhile, we conclude that cross-correlation is weaker in the California market than in the PJM market by studying the two consecutive years of the California 1999-2000 and PJM 2001-2002 power markets. We also discuss how the time intervals affect the cross-correlation exponents of the power operating data based on time-delay MF-DXA. An interesting finding is that the biggest cross-correlation exponent of the two series appeared in about 12 days time delay for the PJM 2001 power market and strongest cross-correlation in the California 1999 power market is found in lots of cyclical time intervals.
会议论文集名称：
2011 3rd International Conference on Computer and Automation Engineering(ICCAE
2011)(2011年第三届IEEE计算机与自动化工程国际会议)论文集
关键词：
Binary tree;lowest common ancestor;Criterion
摘要：
Finding the lowest common ancestor (LCA) of two nodes in a binary tree has been focused both in graph theory and computer science. The paper puts forward and proves an analytic criterion for the LCA of two neighboring nodes in a complete binary tree. The criterion mainly concerns addition, subtraction and bitwise operations, needs no searching procedures and thus is easy to implement in software programming as well as hardware programming. An algorithm that has logarithmic time complexity is also presented with C-language implementation in the paper.
作者机构：
[何新益; 郭婷] Department of Food Science, Tianjin Agricultural University, Tianjin 300384, China;[陈益能] College of Information Science and Technology, Hunan Agriculture University, Changsha 410128, China;[何新益; 郭婷] Tianjin Engineering and Technology Research Center of Agricultural Products Processing, Tianjin 300384, China;[邓放明; 郭婷] College of Food Science and Technology, Hunan Agriculture University, Changsha 410128, China
通讯机构：
Department of Food Science, Tianjin Agricultural University, China
关键词：
水分;核磁共振;干燥;冻融;甘薯;横向弛豫时间
摘要：
为探究冻融处理对甘薯变温压差膨化干燥产品品质影响的机理,应用低场核磁共振技术(low-field nuclear magnetic resonance,LF-NMR)研究了冻融后甘薯中水分存在形式和各组分含量,比较了冻融次数对甘薯膨化干燥产品硬度、色泽和多孔性等品质指标的影响。结果表明:冻融后甘薯LF-NMR自旋-自旋弛豫时间T_2谱中出现4个水分峰,其横向弛豫时间分别为T_(21)(0.25~0.55 ms)、T_(22)(1~2.5 ms)、T_(23)(5~12 ms)、T_(24)(40~200 ms)。随着冻融次数增加,自由水含量(mT_(24))先增加后减少,结合最紧密的水含量(mT_(21))先减少后增加;干燥产品多孔性和复水性逐渐增大,ΔE逐渐变小,L~*和硬度先减小后有稍许增大。相关性分析表明,多孔性与T_(24)、mT_(23)呈现显著正相关(P<0.05),相关系数分别为0.995、0.989;mT_(22)与ΔE的相关系数为0.984。该研究为阐明冻融处理对果蔬变温压差膨化干燥品质变化机理分析提供了理论依据。
摘要：
The use of Cloud computing systems to run large-scale scientific, business and consumer based IT applications has increased rapidly in recent years. More and more Cloud users concern the data privacy protection and security in such systems. A natural way to tackle this problem is to adopt data encryption and access control policy. However, this solution is inevitably introduced a heavy computation overhead. In this paper, we first establish a trust model between Cloud servers and Cloud users. Then, we build the trust-aware attribute-based access control policies according to Cloud user trust level and Cloud request attributes. This technique can give different encryption and decryption data to Cloud user and substantive reduce the computation overhead of Cloud computing.
摘要：
Massive events can be produced today because of the rapid development of the Internet of Things (IoT). Complex event processing, which can be used to extract high-level patterns from raw data, has become an essential part of the IoT middleware. Prediction analytics is an important technology in supporting proactive complex event processing. In this paper, we propose the use of dynamic Bayesian model averaging to develop a high-accuracy prediction analytic method for large-scale IoT application. This method, which is based on a new multilayered adaptive dynamic Bayesian network model, uses Gaussian mixture models and expectation-maximization inference for basic Bayesian prediction. Bayesian model averaging is implemented by using Markov chain Monte Carlo approximation, and a novel dynamic Bayesian model averaging method is proposed based on event context clustering. Simulation experiments show that the proposed prediction analytic method has better accuracy compared to traditional methods. Moreover, the proposed method exhibits acceptable performance when implemented in large-scale IoT applications.
