public-key Encryption Based on Torus Automorphisms

Chaotic maps with its characteristic are very useful in cryptography, however, compared with wide application in symmetric system, the research about chaos in public-key encryption system is still few. Through analysing the period of toms automorphisms which is a prototype of chaotic map, and making use of the framework of the traditional public-key algorithm RSA, the authors propose a chaotic public-key encryption algorithm based on toms automorphisms. Its security is based on the intractability of the integer factorization problem as RSA, and it is able to resist the chosen-ciphertext attack against RSA and easy to be implemented.     

Image Secure Communication Based on Logistic Map

The chaotic sequences generated by logistic map are used as the carrier, and the image secure communication scheme is proposed based on that the sequences possess a good correlation property. Promising results are obtained on Lenna image by computer simulation. The obtained results indicate that the transmitted source image can be correctly recovered and the proposed scheme is reliable when transmitter and receiver using identical initial value even under the situations of a noisy channel. However, the tiny difference of initial value between transmitter and receiver will result in failure to communication. Finally, the quality of recovered source image is assessed, and the approximate formula of bit-error rate in term of code length is also obtained.     

Design and Implementation of Chaos Encrytion Algorithm based on Logistic Formula

The security of stream cipher, which is known as one of the main cipher techniques, dependents completely on the quality of generated pseudo-stochastic sequences. Chaotic systems can produce the pseudo-stochastic sequences with the properties of excessive dependence on initial conditions and the difficulty in forecasting, therefore, these systems are suitable to the stream cipher. A new encryption algorithm is proposed by analyzing the principle of the chaos encryption algorithm based on logistic formula. Moreover, the security and performance of the proposed algorithm is also estimated. Finally, an example is given to demonstrate our method via the Visual C++.     

Logistic map controlled secure arithmetic coding and its application in image encryption

A logistic map controlled secure arithmetic coding is proposed, the Logistic map is used to control the order of the symbols in the model and change the probabilities of the symbols, which is applied to the image encryption. The proposed scheme makes the image transmit more secure and comfortably on the Internet, and that is done at little expense in terms of coding efficiency. In the coding process, it ensures the uniformity of the model being changed by the chaotic sequence, thus to meet the security requirements of image compression. The algorithm can be applied to any arithmetic codec based on multimedia data including video, image and audio. Its most strength compared with other cipher mode is that, there is a significant reduction in the redundancy of information during the compression process, and it is robust when attempting to estimate the information of the image and discovering the key. The scheme can effectively resist differential analyses from both cryptography and coding.     

Walsh Sequences Generation with Rademacher Functions and Its Digital Realization

This paper first discusses the application of Walsh sequences in the forward link and the reverse link of the IS-95 system. The advantages and disadvantages of each way generating Walsh sequences are analyzed. The theory and step of using Rademacher function to construct Walsh sequences is discussed especially. Then a way of generating Walsh sequences with CPLD is presented and the Design is described by VHDL on CPLD chip. This way mostly relays on digital logic operation, so it can be realized easily through digital circuit and it needs little memory unit. The result of emluator makes clear this way is feasible.     

Chaotic Time Series Analysis Based on Radial Basis Function Networks

A method based on radial basis function networks for forecasting chaotic time series is proposed.The nonlinear time series identification problem is formulated with a nonlinear autoregressive moving average(NARMAX)model then a new identification algorithm based on dynamic radial basis function networks is proposed.Then this method is applied to the estimation of embedding dimension for chaotic time series of Henon mapping and the confirmation of the chaotic phenomena in stock markets of China,from which one can get the desired results.Further research directions are also pointed out.     

大白菜单拷贝序列的长片段PCR体系优化

目的序列长片段PCR产物可作为FISH技术的有效探针进行分子细胞遗传学研究。然而,传统PCR技术对于5 kb以上的长片段进行有效扩增很难。合适的反应条件及反应体系是进行长片段PCR有效扩增的必要前提。为了获得目的序列长片段PCR产物以用于FISH研究,根据大白菜A03染色体顶端无重复序列区段设计了80对长片段PCR引物,从基因组DNA模板质量、d NTPs浓度以及退火温度和延伸时间方面对PCR技术体系进行了优化。试验证明,选用幼苗嫩叶的基因组DNA和LA Taq DNA聚合酶可以提高长片段PCR引物的扩增质量和扩增效率;确定了适合5~15 kb长片段PCR的反应体系为20μL:50 ng/μL模板DNA 2μL,2.5 mmol/L d NTPs 1.6μL,10μmol/μL正反引物各1μL,10×LA PCR BufferⅡ(含Mg2+)2μL,5 U/μL LA Taq酶0.2μL;反应条件为98℃变性15 s;58~64℃退火10 s,68℃延伸5 min,35个循环;68℃延伸10 min,4℃保存。在大白菜基因组中成功获得了60对5~15 kb的扩增片段。为在大白菜粗线期染色体上开展长片段PCR-FISH技术研究及在近缘种间开展比较染色体涂染揭示进化关系奠定了理论基础。     

Ceratotropis亚属基于SSR标记和ITS序列的分类与进化分析

利用SSR分子标记和ITS序列分析研究Ceratotropis亚属已鉴定的93份种质以及Vigna亚属的2份地方种和Glycine属的1份野生种,共8个种及亚种的96份材料的遗传差异。初步筛选出分布于11个连锁群(linkage group, LG)的74对小豆引物及14对黒吉豆引物和第9连锁群的5对绿豆引物,得到分辨力强的27对引物,平均PIC值为0.4914;UPGMA聚类分析,在DICE系数0.021处,将95份参试材料(除HAI_103)划分为两大类,第I类包括Ceratotropis组所有种质和3个“过渡”种质,第II类包括Angulares组所有种质;且小豆引物通用性最高：23对小豆引物的转移能力达88%以上。对参试材料中的28份典型种质进行ITS测序分析,比较序列间Kimura进化距离发现,V. minima和 V. umbellata种间距离最小(0~0.005),V. radiata种内分化程度最高;利用MEGA4.0构建最大简约树(maximum parsimony, MP)和邻接树(neighbor-joining, NJ),将参试种质划分为3大类,这与形态学和SSR标记分类一致。     

基于混沌时间序列的马尾松角胫象林间诱捕数量短期预测

为了对马尾松角胫象的防治及松材线虫病的控制提供技术支持,利用混沌时间序列的基本原理,分析马尾松角胫象林间诱捕序列,并重构其相空间及计算最大Lyapunov指数。结果表明：马尾松角胫象林间诱捕序列具有混沌特性。在此基础上,应用加权一阶局域预测模型对马尾松角胫象种群动态进行短期预测,结果显示在最长可预报时间尺度内该模型的预测成功率为100%。     

An algorithm of image processing based on discrete wavelet transform compression and chaotic scrambling

An algorithm was proposed in view of the combination of image compression and encryption. We got the approximate part and three detail parts after transforming the image with discrete wavelet transform (DWT), and compressed the image by modifying the detail parts by a given threshold value based on human visual systems. And then, we encrypted the image by scrambling the approximate part because this part held mostly of the energy. Last, a compressed and encrypted image can be achieved after DWT. Simulation result shows a good effect on the combination of compression and encryption.     

Algorithm and Its Implementation for the Network Maximal Flow

On the algorithm of the network maximal flow, the paper provides a method of achieving it. The concrete procedure is to achieve the algorithm by using stack and structural array. First of all, an adjacency list should be established and its composition chiefly includes orientation, capacity, flux and so on. Afterwards the labeling method is adopted to find the augmenting chain according to the adjacency list. In the process, some spots are stored in the stack by means of the depth superior traverse and range superior traverse and the course way is also conserved in the array. Keep on doinh this till the maximum flow and the flow of each arc are all found.     

基于细胞学和DNA序列的苎麻与其野生近缘类群系统关系研究

为了了解苎麻与野生近缘种的系统学关系,更有效利用野生苎麻资源,通过细胞学观察和分子标记证据,对中国苎麻与其24个野生近缘类群进行了系统学分析。细胞学结果表明,苎麻间期核形态属于田中分类体系的前染色体型,而其野生近缘种分别属于前染色体型和分散型;苎麻和23个野生近缘物种(其中15个类群的染色体数目为首次报道)中,19个为二倍体(2n=28),而大叶苎麻组3个类群为三倍体(2n=42),1个为四倍体(2n=56),1个为五倍体(2n=70)。ITS序列和trnL-F序列分析表明,苎麻属可分成A(含A₁和A₂亚分支)、B(含B₁和B₂亚分支)和C 3个基本分支。根据分析结果本文提出苎麻属的两条演化路线: (1)前染色体型进化路线A₁→A₂,即腋球苎麻组→苎麻组;(2)分散型进化路线B→C,即腋球苎麻组→帚序苎麻组→序叶苎麻组→大叶苎麻组。     

Implementation of PID Algorithm Based on MATLAB in Cascade Control System

This paper presents the character of cascade control system and the design of the main loop and subloop. A cascade PID control system based on MATLAB is designed, which is controlled by MATLAB control program based on incremental PID control algorithm and PID parameter tuning method based on computer control. The results show that the control system has good performance.     

Study and Design on Teaching Experiment Instrument of CT Data Acquisition System Based on CPLD

The purpose of developing Teaching Experiment Instrument of CT is to demonstrate the whole process of CT scanning more intuitively, thereinto the design of data acquisition system is one of the emphases in the developing of the CT system. This paper mainly introduces the design and implement of the data acquisition system of CD - 50BG, using CPLD apparatus which have the characteristic of high integration, in the design of data acquisition system to achieve the target of minishing system bulk and improving system reliability. Aiming at the data loss of CD - 50BG during acquiring data, the data acquisition system is reformatively redesigned, the data loss in the high speed data acquisition process is reduced so that the stability of transmission has been improved by using FIFO.     

Research Advance on Rockburst Theory and Its Engineering Application in Collieries

This paper summarizes and describes the progress in coal rockmass outburst theory in resent decades both at home and abroad,discusses the tendency of mechanism of rockburst,and gives a fullier review about the presently adopted prediction methods and preventive measures,simultaneously looks into the prospective development on the study of prediction and preventive measures and its practical applications.     

基于红掌转录组序列的SSR标记分析与开发

本研究从红掌转录组共32 391条unigenes中搜索得到3 944个SSR位点,出现频率为12.17%。EST-SSR类型以一、二、三核苷酸重复为主,占总SSR比例的96.29%,其中二核苷重复为主要基序类型,占总SSR的51.01%,AG/CT重复类型出现最多。设计合成的200对SSR引物中有22对引物扩增条带清晰、多态性好,在18个红掌品种中得到有效性验证。结果表明,基于红掌转录组序列的SSR标记开发是可行的,这些EST-SSR的开发可为红掌遗传多样性分析、分子育种等奠定重要基础。