基于改进蚁群算法的Web服务选择

提出一种改进的蚁群算法并将其应用于Web服务选择问题中.该算法使用非线性动态变化的伪随机比例选择参数及蚂蚁多重最优解随机加权路由选择算法控制蚁群的行为,使用5维Web服务质量向量和蚁群适应度函数评价蚂蚁构造的路径质量,蚂蚁根据其构造的路径质量进行信息素更新;该算法使蚁群在其解空间的进化能力得到很大的提高.实验证明,该算法在Web服务选择问题上比传统的蚁群算法效率更高.     

受时间、空间约束VRP问题蚁群优化模型及算法的研究

蚁群算法求解组合优化问题是当今智能优化算法的发展方向之一.通过对M.Dorigo提出的传统蚁群优化元启发模型改进,提出了多参数约束蚁群优化元启发式模型.该模型将所有优化约束条件映射为影响人工蚂蚁搜索行为的诱导素;模型中的人工蚂蚁智能行为简单,只根据信息素和诱导素在求解空间中进行搜索,而不进行复杂的运算;该模型减少了人工蚂蚁的求解搜索空间.并通过受时间、空间约束问题VRP(Vehicle Routing Problem)验证了本文提出模型算法较传统蚁群算法简单、收敛性快.     

基于蚁群算法的移动机器人全局路径规划

移动机器人路径规划是机器人学的一个重要研究领域,蚁群算法是一种模拟蚂蚁群体觅食行为的仿生优化算法。结合机器人路径规划的特点,将确定性选择和蚁群算法的随机性选择相结合进行节点转移,每次循环后只对较优蚂蚁路径进行信息素更新,提高了算法收敛的速度;在寻找路径过程中蚂蚁无后继转移节点时,采用蚂蚁回退策略,增强了算法在复杂障碍物环境中寻找路径的健壮性。仿真试验表明,该算法能在障碍物较复杂的情况下迅速规划出较优的全局路径。     

移动AdHoc网络基于蚁群需求的分群路由算法研究

针对移动AdHoc网络因受带宽和电量等因素影响而造成封包遗失机率较高的现象,提出了一种移动AdHoc网络基于蚂蚁算法的需求式群集路由算法.该路由算法利用弱连接支配集群概念,从每个群集广播给其它群集节点,算法中网络上的状态信息通过前行的蚂蚁获得,回退的蚂蚁采用伪随机比例选择策略并根据节点剩余电量、网络平均剩余电量以及路径平均剩余电量来评估从源节点到目的地节点的最佳路径.仿真结果表明:随着网络信息流量的增加,AOCR路由算法在封包抵达率、延迟时间均比AODV和AntSence算法有较大改善,因此,基于蚁群需求的群集路由算法在网络效能上比基于距离矢量路由AODV算法及传统的蚁群路由算法效率更高.     

基于优化蚁群算法的机器人路径规划

路径规划是移动机器人设计中的关键环节,蚁群算法能高效解决路径规划问题,但它也存在一些弊端,如收敛速度慢、容易陷入局部最优解等.针对这些问题,本研究提出一种改进蚁群算法,在传统蚁群算法的基础上,改进状态转移规则,增加周围障碍物数量影响因子,令蚂蚁尽量避开障碍物;增加角度影响因子,使得蚂蚁行走的路径更加平滑;同时运用精英蚁群策略,来改进蚁群算法易陷入局部最优解的问题.仿真实验结果表明,该算法在多种环境下,都能找到最优路径,且有较快的收敛速度,本研究提出的优化蚁群算法具有一定的可靠性和高效性.     

图像边缘检测中的改进算法

针对传统的蚁群边缘检测算法存在耗时长和易受噪声影响的缺点,提出了一种改进的蚁群边缘检测算法.该算法对蚂蚁路径选择中的启发式信息值的计算方法进行改进,使其计算基于邻域中节点的梯度,能更好地引导蚂蚁向边缘节点进行移动.通过仿真实验表明:该算法与传统的蚁群算法相比,能够减少耗时、抑制噪声及准确快速地检测出图像边缘.     

耦合体系拓扑空间的局部损坏与子空间的重构

本文设想由蚁穴和食物源之间多条可能路径形成一个网络结构空间,考察该空间的拓扑结构发生局部改变或出现缺损时,对蚁群寻找最佳路径的影响。采用蚁群优化算法进行模拟计算,构建出让耦合体系重新达到最优状态时所对应的拓扑结构,计算出相应的连接通道。研究发现,利用蚂蚁可搜索出新的路径通道,一方面,蚁群可以搜索出替代的路径通道,构建出子空间来弥补局部缺损带来的影响,恢复体系的相应功能;另一方面,蚂蚁搜寻的最佳路径与出现局部毁损的时间长短有关,分别对应于局部最优解和组合式最优解。研究表明,利用蚁群优化算法,不仅可以构建新的子空间修复信息通路,而且可以通过对信息过载现象来预测和排查神经网络或信息网络中的局部病变或故障所在。     

基于蚁群算法的多字符聚类识别

本文采用蚁群算法对聚类数目已知的多字符进行聚类识别,在分析了基本蚁群算法的基础上,提出了一种改进的蚁群算法,该算法结合分布式计算、正反馈机制、贪婪式搜索算法等.对每只蚂蚁构造一个可行解,利用信息素矩阵,经过若干次的选代,找寻包含最优解的蚂蚁.通过与K-means和遗传算法比较,最后得出结论,该蚁群算法识别效果好,执行效率高.     

TSP的改进蚁群算法求解及其仿真研究

蚂蚁数目是影响蚁群算法性能的重要参数,常规蚁群算法在求解TSP时易于陷入局部最优解。文章针对该问题,提出了一种蚂蚁数目动态改变的蚁群算法,即每次周游时的蚂蚁数目是在一个范围内随机取值,该改进算法借用遗传算法中的排序选择策略对每次遍历时的蚂蚁位置进行初始化;分别对常规蚁群算法的TSP求解和改进蚁群算法的TSP求解进行了原理阐述,并对2种算法求解TSP的结果进行了Matlab仿真。对比仿真结果表明,改进的算法在求解TSP时,能够有效地跳出局部最优解,并能很好地收敛,它比常规蚁群算法的性能要优。     

一种基于分解的改进的多目标蚁群算法及其应用

提出一种基于分解的、改进的多目标蚁群算法。该算法首先利用Tchebycheff聚合方法将整个Pareto最优前沿的逼近问题分解为一定数量的单目标优化子问题,然后利用蚁群算法同时求解这些子问题。为使解集均匀分布在Pareto前沿,采用基于试探的聚类方法对解集聚类;依据解集的分布重置分解策略中的权重向量集,使其适配于特定的Pareto前沿;蚂蚁按照对应的权重距离被分组,同一组蚂蚁共享一个信息素矩阵,该矩阵容纳学习到Pareto前沿子区域的位置信息;每个蚂蚁求解一个子问题,每个蚂蚁拥有自己的启发式信息矩阵;每个蚂蚁拥有多个邻居,蚂蚁选取邻居中的最优解来更新当前解;蚂蚁依据小组信息素,当前解和启发式信息构建新的解。引入自适应变异算子,动态调整蚂蚁邻居的个数,提高算法的收敛速度和解的质量。将该算法与其他相关算法在标准的双旅行商问题进行性能对比,证明该算法有效。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with