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1.
基于两级优化-进化算法的结构优化设计研究   总被引:2,自引:0,他引:2  
针对结构优化设计问题的特点,提出了两级优化-进化算法的优化策略。以一个12层框架结构的优化设计为例,测试了该优化策略的效率,与单独采用进化算法相比,该优化策略在保证优化结果精度的前提下能大幅度提高优化的效率,是一种较好的工程优化方法,虽然以多层框架结构为优化对象,但提出的优化策略完全适用于其它类型结构的优化问题。  相似文献   

2.
构造了求解非线性约束优化问题的杂交进化策略。理论分析和大量实验结果表明,本文算法具有收敛速度快和稳定性好。可应用于实际工程优化计算。  相似文献   

3.
考虑多目标动态加权进化策略不能有效处理高维变量多目标函数的缺点,本文利用差分算法代替进化策略,提出一种多目标动态加权差分算法.最后,通过优化典型多目标优化问题以及电力经济调度模型优化,验证了所提算法的有效性。  相似文献   

4.
对神经网络的研究多年来主要集中于网络权值优化或结构优化上,却忽略了神经网络结构与权值之间密不可分的联系.针对上述问题,将免疫系统中的浓度机制和记忆机制引入进化策略,提出了一种基于免疫进化策略的神经进化算法,在优化网络拓扑结构的同时优化网络的连接权值.进一步地,用Cauchy变异算子代替传统的Gauss变异算子,以获得更为理想的全局收敛效果.理论分析和仿真结果表明,免疫进化策略能够很好地保持种群多样性,避免未成熟收敛,采用免疫进化策略设计神经网络具有良好的全局收敛性能和快速学习网络结构和网络权值的能力.  相似文献   

5.
针对并行遗传算法(parallel genetic algorithms,PGA)容易出现收敛过快和陷入局部最优解的问题,综合多种不同进化策略遗传算法之所长,设计了一种混合的粗粒度并行遗传算法。该算法由多个独立的子群体组成,各个子群体并行的、独立的、按照不同的遗传进化策略进化,每隔一定的时间,在子群体之间进行最优个体的迁移,促进群体的共同进化,并抑制群体早熟。在PVM环境下,用该算法实现函数优化问题,仿真实验数据表明了其有效性.  相似文献   

6.
为解决混合(等式和不等式)约束的多峰优化问题(MOPs),本文在粒子群算法框架下提出了粒子优度比较准则和局部协同与共轭进退寻优两种迭代进化策略.优度比较准则在适应度和约束违反度的双重限制下指导粒子高效地执行进化策略,局部协同策略可使粒子能通过局部抱团收敛到多个全局最优解,而共轭进退寻优策略则提升了寻优的速度和精度.基于优度比较准则与两种进化策略的有效结合,本文设计了一个协同共轭进退粒子群(CCARPSO)算法,以充分融合粒子群算法的全局搜索能力和共轭进退法的局部快速寻优能力.数值仿真表明,该算法能有效解决复杂约束MOPs和非线性方程组的多根问题,在广义Logistic分布的参数估计中有全局优化能力和较高的计算精度.  相似文献   

7.
简要介绍了支持向量机(SVM)及其进化支持向量机(ESVM)的基本思想,建立了基于进化支持向量机的岩土体材料参数反分析模型,并采用进化支持向量机来反演岩土体位移.通过Matlab优化工具箱解相应的优化函数来验证工程算例.由结果可知,进化支持向量机的位移反分析精度较高,相对误差小,有广阔的应用前景和实际意义.  相似文献   

8.
伪并行遗传算法在供水管网优化调度中的应用   总被引:3,自引:0,他引:3  
讨论了基于微观水力模型的多水源大型供水管网优化调度问题的主要特征,并提出了求解该问题的改进遗传算法.首先,针对决策变量的结构提出二进制-实数混合编码策略;其次,设计并实现了多种群进化的伪并行遗传算法.将本算法与单一群体进化算法同时应用于实际管网的优化调度求解,结果表明,通过个体迁移策略,伪并行遗传算法可以加速优化搜索的进程,显著改善解的质量,并有效节省运行调度费用.  相似文献   

9.
提出了一种求解混合整数非线性规划(Mixed integer nonlinear programming,MINLP)的混合差分进化(Differential evolution,DE)算法。为提高DE算法的优化性能,设计了混沌初始化种群、可平衡全局探索与精细开采能力的混合变异版本、基于种群进化停滞代数记录的自适应二次变异算子等新型策略。将前述策略融入DE算法,形成面向MINLP的自适应变异差分进化(Adaptive mutation differential evolution,AMDE)算法。6个MINLP数值实例的对比实验表明了新算法的有效性和可靠性。最后,应用AMDE算法求解齿轮传动体积最小化工程优化设计实例,显示了该算法的工程应用价值。  相似文献   

10.
粒子滤波器作为常用的非高斯非线性的滤波方法,已成功地应用于各种工程领域。然而传统的重采样方法导致了粒子贫化的问题,严重降低了滤波估计的精度与鲁棒性。文中提出一种结合跟踪失败检测与改进差分优化融合的自复位粒子滤波方法。首先通过跟踪失败识别方法对滤波估计值进行初步检验,在正常跟踪时不启用优化策略,算法性能与标准粒子滤波无异;在跟踪失败时,通过差分算法对粒子集进行复位,复位过程中设置了粒子置信区间的上下界以防粒子过度集中,并结合检验指示值规避对粒子的多次优化,以缩短算法的估计时间。仿真结果表明,文中算法通过动态调节方式继承了标准粒子滤波和差分进化粒子滤波的优点,有效提高了滤波估计的鲁棒性与估计精度,可在滤波成功时避免启用优化策略以降低算法的整体时间复杂度,并在滤波失败时启用差分优化策略进行自我复位以提高算法估计精度;且在相同定位精度下,其所需粒子数较标准粒子滤波更少,整体时耗较差分进化粒子滤波更低,在建模不确定时也可表现出良好的效果。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
14.
Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications (up to 574.8 km/ h test speeds or 380 km/h commercial speeds) in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.  相似文献   

15.
Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to  相似文献   

16.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

17.
Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.  相似文献   

18.
The concept of nanopore analysis, using the pore-forming protein a-hemolysin to detect individual nucleic acids at a single-molecule level, was first proposed in 1996. Over the past two decades, tremendous progress has been made in the nanopore field, and nanopore analysis has become a label-free and high-throughput method for probing bio- molecules and other analytes with single-molecule sensi- tivity, especially holds the promising for "third generation" DNA sequencing. However, challenges still remain in the experimental strategies and the design of whole nanopore-based instruments. Here, we proudly present a special topic dedicated to the topic of "Nanopore Analysis", with 8 reviews/articles providing up to date coverage of the experimental strategies, theoretical calcu- lations and simulations, and instrument design. Reviews and articles on the experimental strategies cover control of DNA partitioning into a nanopore, detection of target DNA, and the advantages of nanopore-based DNA sequencing. The theoretical calculations and simulations discuss the translocation behavior of DNA, and an inte- grated measurement system and data analysis software are presented for instrument design.  相似文献   

19.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

20.
<正>1 Introduction Endeavours on learning methods have long occupied the mind spaces of scholars and there have been theories abound on how people learn and in what way organisations can use some of the knowledge gained in the art of learning to maximise human productivity.While the theories by themselves are not solutions to problems,they are steps of inquiry that provide us with interesting perspectives that we can use to extend our knowledge of the dimensions of learning.This paper is an exploratory work on the theories postulated by three notable scholars including Zimmerman  相似文献   

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