自适应调整子种群个体数目的遗传算法及其应用

为了协调算法的勘探和开采能力,提出一种自适应调整子种群个体数目的遗传算法.该算法首先采用佳点集方法初始化种群以保证个体均匀分布在搜索空间中.基于个体的适应度将种群分为3个子种群,并分别采用不同的交叉和变异算子.在进化过程中,根据不同的搜索阶段自适应动态调整各子种群个体的数目.几个标准测试函数的实验结果表明该算法具有较好的寻优性能.将新算法应用到重油热解模型参数估计中,可以获得满意的结果.     

基于自适应退火遗传算法的船舶管路布局优化方法

采用自适应遗传算法来确定标准遗传算法的杂交率和变异率,尤其对变异率的调整,使其不但能根据个体适应值的大小进行自适应修正,而且能随进化状态的改变而改变,从而增强了算法摆脱局部最优解的能力.同时引入模拟退火思想,通过对标准遗传算法接受算子的退火处理,使其在搜索过程中除了接受优化解以外还以Metropolis准则接受恶化解,提高了种群的多样性,有效地增强了全局寻优能力.通过对适应值函数的退火拉伸,调整了进化前后期的适应值差异,从而加速了寻优过程.最终以形成的自适应模拟退火遗传算法进行船舶管路的三维布局优化,仿真实验表明,该算法不但加快了寻优速度,而且与标准遗传算法相比全局收敛率提高了近30%.     

遗传算法参数自适应控制的新方法

根据遗传算法参数自适应控制方法的不同分类,采用基于启发式规则的参数控制方法对遗传算法的种群数进行了宏观调控和微观调控。并采用不同特点的模糊控制器分别控制交叉率和变异率,使种群数、交叉率和变异率都能够随进化的实际情况发生自动调整,形成了一种新的种群数变化的模糊自适应遗传算法。实验数据表明这种算法能够有效防止遗传算法早收敛,同时也说明对参数进行自适应控制能够使遗传算法性能大大提高。     

基于离散变量自适应遗传算法的改进

在自适应遗传算法中交叉算子和变异算子随着其适应度变化自动改变其值,从而影响遗传进化的过程,但算法在进化初期对遗传操作的效果并不明显。本文针对离散变量的特征,通过计算个体间的离散程度,判断种群的进化程度,根据不同的进化时期自适应调整交叉概率和变异概率,使得种群的交叉和变异配合进行,有效地解决了离散变量在进化初期容易陷入局部寻优的问题。实验结果表明,算法经改进后,其全局收敛的可靠性增加并加快了收敛的速度。     

小生境遗传算法的改进

为了避免小生境遗传算法存在的早期成熟和陷入局部极值点等问题,提出了一种改进的小生境遗传算法.该算法基于自适应交叉概率算子和变异算子,根据进化代数和群体的适应值,动态调整各个个体的交叉概率和变异概率,并在变异量的确定上引入了梯度的概念.通过在Shubert函数的全局最优化问题上的验证,并与常规遗传算法和小生境遗传算法比较,改进后的算法提高了搜索速度,能有效跳出局部极小值,并搜索到全局最优值.     

基于改进自适应遗传算法的船联网拓扑优化算法

提出了一种改进的自适应遗传算法优化船联网拓扑结构.考虑实际应用场景,以及网络的连通度、节点度、通信链路质量及通信成本等因素,最大化船联网总链路增益.改进的遗传算法在选择操作中,提出自适应个体适应度调节公式,动态调整当前种群中个体的适应度值,减小个体间适应度的差值,增加适应度较低个体通过选择过程进入下一步操作的概率,提高种群多样性.交叉和变异过程中,引入自适应调节系数,调整交叉和变异概率,尽可能使适应度值较高的个体进入下一次迭代过程.仿真实验表明,提出的改进算法能够避免早熟收敛,跳出局部极值,最终收敛得到船联网最优拓扑结构,且收敛速度更快,算法效率更高.     

一种改进的自适应差分进化算法

为了提高基本差分进化算法的寻优速度和寻优效能,提出了一种改进的自适应差分进化算法(ADE).在基本差分进化算法中引入了自适应变异算子,根据每个个体与最优个体适应度值的相互关系,自动地调节变异算子值,使之在进化初期较大,随着个体逐渐接近最优值,算子值逐渐变小,确保个体向最优值快速、稳定地逼近.在每一代变异、交叉和竞争之后,又增加了与随机新种群的竞争操作,使算法易于跳出局部最优点,以提高全局搜索能力.采用4个经典的测试函数对算法进行验证,结果显示:该算法的收敛速度与收敛精度在一定程度上优于基本差分进化算法,同时也优于基于代数进行自适应变异的差分进化算法.     

基于改进模式提取变异算子的遗传算法

在经典遗传算法的基础上，提出了一种基于改进模式提取（Algorithm of pattern extraction,Alopex)，种群个体的连续进化方向作为当前代个体的变异方向，并利用自适应来调整变异步长，通过控制参数来控制变异方向的概率从而跳过局部最优值。对几种典型函数的测试结果表明，基于该变异算子的遗传算法能较好地避免收敛到局部最优，收敛性能优于经典遗传算法。     

改进自适应遗传算法在BP神经网络学习中的应用

针对遗传算法容易产生局值的问题,提出一种新的自适应遗传算法,改进遗传算子,通过比较两代之间的适应度评估值,选取适合的交叉率和变异率,保证了优秀个体进入下一代,而且避免了种群中最大适应度值的个体的交叉率和变异率为0的情况.最后,将改进后的算法应用于库存控制模型,实验表明,改进后的自适应遗传算法能避免局值,提高网络的收敛速度,改善了网络的学习性能.     

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。     

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.     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.