基于鲁棒成本函数的随机模糊神经网络参数学习算法

为了解决采用最小方差型的误差成本函数进行输入含噪系统参数学习时的随机模糊神经网络(SFNN)参数不能收敛至真值的问题,将包含噪声方差的误差成本函数推广到多入单出系统,并根据鲁棒统计学理论和目标函数在参数学习中的导向作用,对目标函数进行修正,使之对于不服从统计分布的粗大误差也能有效处理.在此基础上提出了SFNN的鲁棒参数学习算法,并且输入输出数据中的噪声方差也通过学习而得到,从而避免了需要多次测量的要求.结果表明,SFNN的鲁棒参数学习算法能抑制粗大误差和系统噪声.最后,通过仿真对比验证表明了该方法的有效性.     

回转型水下航行器艇体数学建模方法和最小阻力研究

一直以来在水下航行器的艇体外形设计上都采用传统船舶设计方法,尝试采用数学建模方式描述水下航行器的型值,通过计算型值及推导相关参数的计算公式,并根据水下航行器已知设计参数得出不同数值情况下的型值函数,最终通过数学计算方法与图谱查找方式得出最优航行器艇体型状.     

基于改进强跟踪滤波器的微小型水下机器人船位推算

针对微小型水下机器人低速航行时的水下导航问题,提出一种基于改进强跟踪滤波器的船位推算方法.引入Sage-Husa量测噪声估计器以及自适应调节因子,通过改善渐消因子的大小,使得微小型水下机器人在机动性能较低情况下仍能加强滤波器的跟踪能力,提高滤波精度.以SY-1载体为研究对象进行的仿真试验验证了该方法的可行性和有效性.     

基于单隐层前馈神经网络的优化算法

前馈神经网络是神经网络中最常用的函数近似技术。根据普适定理,单隐层前馈神经网络(a single-hidden layer feedforward neural network,SFNN)可以任意接近相应的期望输出。一些研究人员使用遗传算法(genetic algorithms,GAs)探索FNN结构的全局最优解。然而,使用GAs来训练SFNN是相当费时。提出了一种新的SFNN优化算法。该方法是基于凸组合算法(convex combination algorithm,CCA)在隐含层上分析信息数据。事实上,该技术是将分类遗传演算法结合交叉策略的GAs算法。改进方法比GAs算法性能更优,但在进行学习和遗传演算前需要大量预处理工作如将数据分解为二进制代码。同时设置一个新的误差函数量化SFNN性能、获得连接权值最优选项以直接解决非线性优化问题。采用几个计算实验验证改进算法,结果表明改进方法更适合寻找单隐含层SFNN的最优权重。     

基于样本熵和IFOA-GRNN的多普勒计程仪信号失真重构

在水下无人航行器(UUV)的航行过程中,由于内部复杂磁场的干扰,用于测量自身速度和航位推算的多普勒计程仪(DVL)有可能会出现信号失真。为此提出一种基于样本熵与广义回归神经网络的DVL信号失真的重构方法。首先引入鸡群优化算法(CSO)中求解高维优化问题的思想,增强传统果蝇优化算法(FOA)中局部搜索的能力和跳出局部极值点的能力。然后使用改进的果蝇优化算法(IFOA)对广义回归神经网络进行训练,得到UUV的估计速度。在UUV航行过程中,实时计算DVL输出信号的样本熵,根据设定阈值判断DVL的工作状态。最后使用DVL正常的航行数据与海流估计修正UUV航行过程中的海流干扰。DVL失真情况下的UUV应急导航仿真试验验证其有效性。     

一种新的不下机器人运动控制方法

对神经网络和模糊理论在水下机器人运动控制中的应用进行了探讨,提出了神经网络多步预测模型的非线性广义模糊预测控制算法,用神经网络方法实现了对水下机器人这一非线性系统的在线计算、滚动优化和在线控制,采用强化学习方法来构筑模糊控制系统中的神经网络,给出了神经网络多步预测模型及相应的控制算法和操作过程,计算机仿真结果验证了本文所提方法的有效性。     

基于模糊神经网络的PI自适应控制器

利用模糊神经网络的模糊推理能力以及前馈神经网络的逼近能力 ,将其与自适应控制方案结合 ,并取带有控制增量约束的广义目标函数作为优化指标 ,从而推导出一种能对非线性非最小相位系统进行有效控制的模糊神经网络间接自适应控制器。在网络学习算法上采用带有动量项的BP算法。仿真结果表明了该方法的有效性。     

水下航行器耐压壳体参数化设计优化

为提高水下航行器耐压壳体结构设计效率,研究了基于参数化分析和响应面近似模型的耐压壳体结构优化设计方法.确定某型水下航行器的耐压壳体结构5个尺寸为优化设计变量,应用薄壳理论和CCS规范进行了初步设计并确定了优化变量可行域,采用最优拉丁超立方法(Opt LHD)在可行域空间内确定设计试验样本点,研究了ABAQUS参数化驱动样本点的方法,建立了极限载荷的二阶多项式响应面模型.以极限载荷和壳体质量为优化目标,利用二代非劣排序遗传算法进行耐压壳体的多目标优化求解,得到Pareto最优解集.最终优化结果较初步设计结构极限载荷提高41.68%,壳体质量降低27.26%.参数化方法能够简化优化过程,提高优化效率,为水下航行器结构优化设计提供了借鉴.     

六自由度水下航行器操纵性仿真及性能评估

为预报水下航行器样机操纵性和运动控制性能,采用格特勒标准六自由度运动方程,通过水池拖曳试验获取水动力系数,建立水下航行器运动模型,完成水平面回转操纵、Z型操纵、回舵操纵、垂直面梯形操纵和空间螺旋操纵等仿真.仿真结果表明:该水下航行器具有良好的应舵性能和回转性能,同时具有良好的机动性和稳定性;并将全模型仿真与经典的野本简化模型仿真结果进行比较,说明了本方法的精确性.对操纵性能的评估结果表明所设计的水下航行器满足水下智能控制试验平台的要求.     

基于模糊神经网络的无人水下航行器航迹跟踪控制

针对外界扰动的无人水下航行器航迹跟踪控制问题,通过定义一个动态滑模面,结合Lyapunov稳定性理论,设计航迹跟踪滑模控制器.考虑到系统中存在的未建模动态,在保证不引入模型参数的前提下,采用模糊神经网络在线逼近理想滑模控制律,并根据Lyapunov稳定性理论及投影算法得出模糊神经网络的参数自适应律.理论分析证明闭环控制系统的一致渐近稳定性、所有变量的有界性及跟踪误差及其导数渐近趋向于零.仿真实验验证了所提控制策略的有效性.     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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