遗传算法编码策略研究

遗传算法是—类基于自然选择和自然遗传机制的自适应全局优化概率搜索算法,编码策略是设计遗传算法的一个重要步骤,通过研究二进制码和格雷码的编码策略,分析了编码差异、个体差异和适应度差异之间的关系,得到了两种不同编码对遗传算子搜索能力的影响和它们的特性。     

基于改进自适应遗传算法的小径短绳自动打捆机步进电机PID控制

为提高小径短绳自动打捆机步进电机的控制精度,在分析经典遗传算法和经典自适应遗传算法的基础上,引入进化代数和个体适应值排名来指导自适应交叉率和自适应变异率,设计了一个基于改进自适应遗传算法的PID控制器,以削弱进化过程中优良参数的退化现象。MATLAB仿真结果表明,改进的自适应遗传PID提高了收敛精度,并具有更快的收敛速度。针对步进电机的实际测试结果表明,与经典遗传算法相比,改进的自适应遗传PID调整时间更短、超调量更低。     

基于遗传算法的嵌入式系统软硬件划分算法

针对嵌入式系统软硬件协同设计中的软硬件划分问题,提出了一个基于基本调度块图的软硬件划分模型,并给出了一个基于遗传算法的软硬件划分算法.通过采用自适应的适应度函数和演化策略,提高了算法的稳定性、搜索效率和求解质量.实验结果说明了该算法对解决软硬件划分问题是有效的.     

《演化计算》

该书主要包括遗传算法、演化策略、演化规划和遗传程序设计 4个分支。该书从演化计算的算法设计、理论分析和应用的角度对演化计算这一新技术进行系统全面的阐述和讨论。包括演化算法的基本结构及原理、步骤 ,介绍了几种演化计算理论分析方法 ,讨论了演化算法在优化、非线性参数估计、自适应建模和神经网络系统设计等领域的应用及其并行实现 ,演化计算中近年来兴起的新方向——演化硬件等内容。该书可作为相应学科的研究生教材 ,也可供有关科研人员和工程技术人员阅读参考。该书由清华大学出版社出版。《演化计算》     

在内部演化硬件中实现自适应变异参数控制

为了在演化过程中优化演化算法性能和避免花费大量时间在演化算法的参数设定中,设计了一种新颖的基于硬件实现的自适应变异比率控制方法.为了实现自适应特性,变异比率控制参数也被编码到染色体中作为附加的基因经历演化操作.本方法的有效性将通过和传统的采用固定变异比率的演化算法在演化4-bit偶校验函数(even-parity function),2-bit乘法器和3-bit乘法器的对比实验中进行证明.实验平台建立在一个完全FPGA实现的内部演化硬件上,它的设计思想来源于笛卡尔遗传程序(Cartesian Genetic Programming).在所有实验中,基于自适应变异比率控制的演化算法的性能明显优于传统的采用固定变异比率的遗传算法.     

基于遗传算法的神经网络金融时序预测的研究

基于简单遗传算法的神经网络训练速度慢、易陷入局部极值,用具有较好的全局搜索能力自适应遗传算法来优化神经网络权值和国值,设计了基于自适应遗传算法的BP神经网络的股票预测系统．该系统根据对股票历史数据分析,预测股价未来几天时间的走势．结果表明,改进算法具有很强的可行性和高效性．     

遗传算法在随机组卷中的应用

随机组卷是在线考试系统要解决的重要问题之一。本文介绍了针对演化计算的三大分支之一的遗传算法进行改良实现随机组卷问题,详细阐述了遗传算法的主要思想、随机抽题问题的编码表示、适应性函数和遗传算子的设计、淘汰策略和停机准则的选择。     

基于遗传算法的数据库多连接查询优化策略

结合多连接查询的特点,提出了一种基于遗传算法的查询优化策略.在查询左深树策略空间上构造了遗传算法的一个原型,设计出查询优化问题的染色体编码方法,并基于该编码方法给出了选择策略及交叉、变异算子.     

基于Agent的分布式入侵检测模型研究

传统的入侵检测系统多采用集中式的分析引擎,误报率较高且缺乏自适应性,难以满足大规模分布式网络环境的安全需求.Agent技术有效地解决了网络间任务分配合作问题,本文提出了一种基于移动Agent的主动网络自适应入侵检测系统.系统通过响应分析,自动产生响应策略,并派遣移动Agent去执行;根据入侵检测系统的报警可信度和响应执行情况,系统能够自适应地调整响应策略.同时,针对现有大多数模型具有较高漏报率的问题,提出一种基于蜜罐分布式的入侵检测系统模型.     

基于Honeyd的产品型蜜罐系统

在研究型蜜罐技术的基础上,分析了产品型蜜罐所应具备的基本特性,设计并实现了一个基于Honeyd的产品型蜜罐系统.系统应用了公钥加密、图形化操作等技术,具有较高的安全性和实用性.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.