A universal algorithm to generate pseudo-random numbers based on uniform mapping as homeomorphism

A specific uniform map is constructed as a homeomorphism mapping chaotic time series into [0,1] to obtain sequences of standard uniform distribution. With the uniform map, a chaotic orbit and a sequence orbit obtained are topologically equivalent to each other so the map can preserve the most dynamic properties of chaotic systems such as permutation entropy. Based on the uniform map, a universal algorithm to generate pseudo random numbers is proposed and the pseudo random series is tested to follow the standard 0-1 random distribution both theoretically and experimentally. The algorithm is not complex, which does not impose high requirement on computer hard ware and thus computation speed is fast. The method not only extends the parameter spaces but also avoids the drawback of small function space caused by constraints on chaotic maps used to generate pseudo random numbers. The algorithm can be applied to any chaotic system and can produce pseudo random sequence of high quality, thus can be a good universal pseudo random number generator.

IMIBSE与ISOMAP在旋转机械故障诊断中的应用

针对基本熵的区域划分标准不理想,导致无法有效测量振动信号的复杂度,使故障诊断的准确率不佳这一问题,提出了一种基于改进多尺度改进基本熵(IMIBSE)、等距特征映射(ISOMAP)和随机森林(RF)的旋转机械故障诊断方法。首先,采用基于方差的区域划分准则对基本熵进行了改进,结合改进的粗粒化处理,提出了IMIBSE,并将其用于提取故障特征;随后,利用ISOMAP对原始故障特征进行了特征降维,选择了对分类贡献最大的一组特征作为故障敏感特征;最后,基于RF建立了多故障分类器,将故障敏感特征输入至RF模型进行了训练和测试,实现了旋转机械的故障识别,利用齿轮箱和离心泵两种故障数据集将IMIBSE方法与复合多尺度基本熵、多尺度改进基本熵、多尺度基本熵进行了比较和分析。研究结果表明:IMIBSE不仅具有最佳的可视化效果,而且取得的识别准确率最高,二者均达到了100%,而二者的平均分类准确率分别为100%和99.8%;相较于其他故障诊断方法,IMIBSE方法的准确率更高,而且适用于小样本的故障识别问题。

Measuring the Qatar-Kazeron Fault Dip Using Random Finite Fault Simulation of September 27, 2010 Kazeron Earthquake and Analytical Signal Map of Satellite Magnetic Data

In this research the fault parameters causing the September 27, 2010 Kazeron Earthquake with a magnitude of MW = 5.8 (BHRC) were determined using the random finite fault method. The parameters were recorded by 27 accelerometer stations. Simulation of strong ground motion is very useful for areas about which little information and data are available. Considering the distribution of earthquake records and the existing relationships, for the fault plane causing the September 27, 2010 Kazeron Earthquake the length of the fault along the strike direction and the width of the fault along the dip direction were determined to be 10 km and 7 km, respectively. Moreover, 10 elements were assumed along the length and 7 were assumed along the width of the plane. Research results indicated that the epicenter of the earthquake had a geographic coordination of 29.88N - 51.77E, which complied with the results reported by the Institute of Geophysics Tehran University (IGTU). In addition, the strike and dip measured for the fault causing the Kazeron Earthquake were 27 and 50 degrees, respectively. Therefore, the causing fault was almost parallel to and coincident with the fault. There are magnetic discontinuities on the analytical signal map with a north-south strike followed by a northwest-southeast strike. The discontinuities are consistent with the trend of Kazeron fault but are several kilometers away from it. Therefore, they show the fault depth at a distance of 12 km from the fault surface.

Mapping landslide susceptibility at the Three Gorges Reservoir, China, using gradient boosting decision tree,random forest and information value models

This work was to generate landslide susceptibility maps for the Three Gorges Reservoir(TGR) area, China by using different machine learning models. Three advanced machine learning methods, namely, gradient boosting decision tree(GBDT), random forest(RF) and information value(InV) models, were used, and the performances were assessed and compared. In total, 202 landslides were mapped by using a series of field surveys, aerial photographs, and reviews of historical and bibliographical data. Nine causative factors were then considered in landslide susceptibility map generation by using the GBDT, RF and InV models. All of the maps of the causative factors were resampled to a resolution of 28.5 m. Of the 486289 pixels in the area,28526 pixels were landslide pixels, and 457763 pixels were non-landslide pixels. Finally, landslide susceptibility maps were generated by using the three machine learning models, and their performances were assessed through receiver operating characteristic(ROC) curves, the sensitivity, specificity,overall accuracy(OA), and kappa coefficient(KAPPA). The results showed that the GBDT, RF and In V models in overall produced reasonable accurate landslide susceptibility maps. Among these three methods, the GBDT method outperforms the other two machine learning methods, which can provide strong technical support for producing landslide susceptibility maps in TGR.

MapGIS制图中随意参数底图的矢量校正

基于MapGIS软件系统分析和东准噶尔地区空间多元地学信息找矿预测工作,针对无矢量化随意参数地质图件资料的矢量校正,提出了关键点配准法的底图矢量校正方法;对于无配准矢量化图件的矢量校正,提出了关键点坐标法和关键点距离法2种解决方案。研究表明,采用关键点配准法可有效解决传统单幅底图法存在的累计误差大及工作效率低等问题。对于无配准普通数字化图件的矢量校正,可采用关键点坐标法和关键点距离法实现,前者是解决无配准矢量化图校正的最佳方法,适用于原始底图中有4个或以上的关键点,校正后的图件图元信息准确,后期不需要进行点、线图元参数的调整,具有误差小、效率高的特点;当无配准矢量化图中关键点数量少,不适用关键点坐标法时,可采用关键点距离法进行校正。这3种方法对提高成果资料的利用水平,促进空间多元地学信息找矿预测的有效性和准确率有重要意义。

基于POCS-MPMAP合成算法的超分辨率图像复原(英文)

阐述了凸集投影理论 (POCS)和基于Markov约束的Poisson MAP超分辨率图像复原算法 (MPMAP) 为了能获得更大的带宽扩展和更好的复原图像 ,把POCS理论与MPMAP算法结合在一起 ,提出基于POCS MPMAP的合成超分辨率图像复原算法

MOLMAP指数及其在变异性预测中的应用

分子映射(MOLMAP)指数是以分子的化学键描述符为基础,通过Kohonen自组织映射依据一定的算法而衍生.化学键描述符是由化学键的物理化学性质,如两端原子的电荷差和拓扑性质,键连杂原子数量等所组成.本文将分子映射指数应用于4075个有机物质(Ames实验结果:2305个结构有诱变性,1770个结构无诱变性)的变异性预测.通过随机森林,分别采用三种类型的指数建立模型:(1)采用不同维数的分子映射指数;(2)采用全局分子描述符;(3)将分子映射指数与全局分子描述符相结合.整个数据集的集外(out-of-bag)交叉验证的正确预测率达到85.4%.为了检验模型的稳定性,采用所建模型预测源于另一数据库的472个化合物,正确预测率为86.7%,与此前的研究相比,两个预测结果均有所提高.

伪随机码相关检测的MDS-MAP定位算法

针对当前无线传感器网络超声波设备定位精度不高的问题,改进了伪随机码相关的MDS-MAP定位算法。首先利用伪随机码相关检测技术,对节点发射出的超声信号进行编码,有效地增加了节点的测距距离和测量精度。然后对于未能测量到距离的节点使用Euclidean和最短路径融合算法进行处理,然后使用MDS-MAP算法生成节点的相对坐标,最后利用平面转换模型获取节点的最终坐标位置。仿真实验结果表明改进算法在不同网络规模和测距误差条件下均能够获得更高的定位精度和较小的定位误差。

一种MRF-MAP框架下的图像超分辨率重建方法

基于多帧观察样本的超分辨率图像重建是超分辨率图像重建研究中的重要方向.在马尔科夫随机场-最大后验概率(MRF-MAP)框架下研究了多帧图像的超分辨率重建问题.根据给定的空间图像退化模型建立了超分辨率重建的二阶能量函数,并利用α-expansion图切算法对能量函数进行求解.考虑到α-expansion算法的规范性要求,将能量函数进行近似.针对二阶能量函数的图切算法,讨论了s-t图的构造,给出一种节点的分配方法以及t-link和n-link的赋值方式,以提高图切算法的计算效果.通过对两种类型的图像进行超分辨率重建的对比实验,表明该方法具有较好的去噪及重建效果.

在MapInfo中实现区域对象样点布设功能

随着GIS在森林资源管理中应用的不断深入,在GIS系统中实现林业专业抽样设计功能是非常必要的。本文使用MapBasic编程语言实现三种样点布设功能。操作时,用鼠标点击欲布样点区域,在弹出对话框中作出回答,就能得到样点布设图和样点坐标表。

基于MRF-MAP的运动矢量恢复差错掩盖算法

针对帧间编码模式下出现图像块丢失的情况,提出一种有效的时间域运动矢量恢复差错掩盖算法。把运动矢量场建模为高斯马尔科夫随机场,对丢失图像块的运动矢量采用最大后验概率方法恢复,其权值能够根据空间和时间信息而自适应选择。仿真结果表明,该算法在客观和主观上都能获得高质量的图像。

基于MAP和RF的无监督SAR图像变化检测

基于形态学属性断面(MAP)和随机森林(RF)分类器,提出了无监督合成孔径雷达(SAR)图像变化检测方法.首先,利用MAP算法提取差异图像的几何结构特征,构造深入描述图像结构化信息的特征向量空间;然后,在结合阈值法和偏移因子自动选取训练样本的基础上,用RF分类器在多维特征空间中对图像进行变化与否的判别;最后,利用数学形态学方法对虚警进行滤除.实验结果表明,与传统的基于阈值的变化检测方法相比,该方法不仅能很好地检测出变化区域,而且具有更高的检测精度.

基于MAP风险模型的最优分红问题研究

在保险公司财务核算和分红均发生在随机时间点的假设条件下,讨论保险公司的最优分红问题.假设保险公司的盈余过程是经过MAP(马氏到达过程)的相过程调制的复合泊松过程,保险公司对盈余过程的观测和分红都发生在MAP的跳点上,以最大化期望折现分红总量为目标,证明了最优分红策略为band策略,并分析了经济状态和分红机会对值函数和分红策略的影响.

遥感图像的MAP超分辨重建

遥感根本目的就是获得清晰的高空间分辨率的图像,从而可以进一步地分析处理。为了在遥感测量中获得更高空间分辨率、更高信噪比、更清晰的图像,本文对图像处理领域超分辨算法进行了研究。建立了一套拟合模拟现实的成像系统模型,在这种模型的基础之上,利用最大后验概率系统理论,讨论了现实情况中的运动模糊,噪声等情况,改进了MAP超分辨算法。实验结果表明:使用本文改进的基于MAP理论的Markov随机场约束的多帧超分辨重建算法,可以较好提高超分辨效果,与三次立方插值方法相比,PSNR至少提高约5.1dB左右,与未改进的MAP方法相比,PSNR提高约0.2dB左右。本文提出了动态的先验约束方法,给约束函数添加与迭代次数相关的约束项,该改进创新可以加快收敛并且更加逼近真实图像,实验表明该方法收敛速度更快,约束效果良好,更适合实际应用。

Statistical Approaches to Mapping QTL of Dynamic Traits

Quantitative traits whose phenotypic values change with time or other quantitative factor are called dynamic quantitative traits. Genetic analyses of dynamic traits are usually conducted in one of two ways. One is to treat phenotypic values collected at different time points as repeated measurements of the same trait, which are analyzed in the framework of multivariate theory. Alternatively, a growth curve may be fit to the phenotypes at multiple time points and inference can be made through the parameters of the growth trajectories. The latter has been used in QTL mapping for developmental traits and resulted in an appearance of the functional mapping strategy. Aiming at the disadvantages of functional mapping strategy, we propose to replace the nonlinear and non-additive model biological meaningful by the orthogonal polynomial or B-Spline model to fit dynamic curves with arbitrary shape and analyze arbitrary complicated data, and the constant residual covariance matrix by the alterable one calculated by using auto-correlation function to deal with discrepancies in measurement schedule of phenotype among progenies. A novel RRM mapping strategy was developed for mapping QTL of dynamic traits, which performs higher detecting efficiency than functional mapping, especially for detection of multiple QTL, has been proved by our simulations and data analysis. Finally, a simplified and effective mapping strategy was further discussed by integrating functional mapping and RRM mapping strategies.

Mapping regional cropping patterns by using GF-1 WFV sensor data

The successful launched Gaofen satellite no. 1 wide field-of-view （GF-1 WFV） camera is characterized by its high spatial resolution and may provide some potential for regional crop mapping. This study, taking the Bei＇an City, Northeast China as the study area, aims to investigate the potential of GF-1 WFV images for crop identification and explore how to fully use its spectral, textural and temporal information to improve classification accuracy. In doing so, an object-based and Random Forest （RF） algorithm was used for crop mapping. The results showed that classification based on an optimized single temporal GF-1 image can achieve an overall accuracy of about 83%, and the addition of textural features can im- prove the accuracy by 8.14%. Moreover, the multi-temporal GF-1 data can produce a classification map of crops with an overall accuracy of 93.08% and the introduction of textural variables into multi-temporal GF-1 data can only increase the accuracy by about 1%, which suggests the importance of temporal information of GF-1 for crop mapping in comparison with single temporal data. By comparing classification results of GF-1 data with different feature inputs, it is concluded that GF-1 WFV data in general can meet the mapping efficiency and accuracy requirements of regional crop. But given the unique spectral characteristics of the GF-1 WFV imagery, the use of textual and temporal information is needed to yield a satisfactory accuracy.

Improving Middle Square Method RNG Using Chaotic Map

One of the classic approaches in PRNGs is the middle square method in which with a simple mathe-matical model generating pseudorandom numbers in high speed and minimum correlation between output numbers. Despite these unique characteristics, the method contains weaknesses that a broader application of this algo- rithm will face. In this paper is studied middle square method and then a logistic chaotic map is introduced with its specific features and its improved weaknesses via using these characteristics. Finally the NIST tests suite s are presented, in order to detect the specific characteristics expected from truly random sequences.

Optical Image Encryption Based on Mixed Chaotic Maps and Single-Shot Digital Holography

Random phase masks play a key role in optical image encryption schemes based on double random phase technique. In this paper, a mixed chaotic method is proposed, which can efficiently solve some weaknesses that one-dimensional (1-D) single chaotic maps encounter to generate random phase masks. Based on the chaotic random phase masks, optical image encryption and decryption are realized with a single-shot digital holographic technique. In the proposed encryption scheme, the initial value and parameters of mixed chaotic maps serve as secret keys, which is convenient for the key management and transmission. Moreover, it also possesses high resistance against statistical attack, brute-force attack, noise attack and shear attack. Simulation results and security analysis verify the validity and security of the proposed encryption scheme. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

2D Conjugate Maps of DNA Sequences

Random sequences play an important role in wider security applications, such as mobile communication and network security. Due to DNA sequences owning natural randomness, in order to show DNA’s characteristics intuitively, this paper proposes a method to present DNA sequences as conjugate maps. The method includes two core models: measuring models to transfer DNA data into measurements, and visual models to test random sequences as distribution maps to show DNA’s characteristics. The spatial relations between sample DNA and CA random sequences are illustrated and compared in the end. The results show that the distribution of DNA sequences and CA random sequences has significant differences and similarities. It can provide a reference for in-depth visualization study of DNA sequences on their measurement maps.

A Self-Adaptive Parallel Encryption Algorithm Based on Discrete 2D-Logistic Map

A self-adaptive parallel encryption algorithm based on discrete 2D-Logistic map is developed according to the position scrambling and diffusion of multi-direction in variable space of spatial chaos. The binary sequences b1b2b3···bn are obtained according to the user key, in which the binary sequence 0 and 1 denote distribution mode of processors and the number of binary sequence n denotes cycle number. Then the pseudorandom 2D matrix is generated by 2D-Logistic map, and adaptive segmentation is applied in image matrix and pseudorandom matrix according to the value and the number of binary sequence. The parallel operation is used among blocks to improve efficiency and meet real-time demand in transmission processes. However, the pixel permutation is applied in partitioned matrix through ergodic matrix generated by pseudo-random matrix-block to decrease the correlation of adjacent pixels. Then the pixel substitution is used for fully diffusing through cipher block chaining mode until n cycles. The proposed algorithm can meet the three requirements of parallel operation in image encryption and the real-time requirement in transmission processes. The security is proved by theoretical analysis and simulation results.