改进BP反传算法在智能控制系统虽的应用

在一般的基于神经网络的智能ＰＩＤ控制基础上，针对受控模型参数，系统设定值以及扰动幅值在大范围内变化的情况，探讨并建立了ＢＰ反传算法学习速率与受控模型参数，系统设定值以及扰动幅值的关系，神经网络控制器在在线调整学习速率，使控制系统具有较强的适应能力和较好的调节品质。     

自整定调节器专家系统

应用不同ＰＩＤ参数对各种控制对象进行在碍实验，观察分析其结果，总结出用波形法进行ＰＩＤ参数自整定的专家系统。系统具有预整定、自整定和自动起动功能，使过程在起动、设定值改变以及过程扰动情况下，根据性能指标要求在线整定ＰＩＤ参数，控制性能保持在较优状态。     

不确定互联电力系统的RBF网络自适应混沌控制

针对互联电力系统的混沌控制问题,建立了一种带有周期性负荷扰动和电磁功率扰动的互联电力系统模型,利用分岔图分析了该模型对各系统参数和外部干扰的敏感性.针对系统内部参数和扰动幅值的不确定性,提出了一种基于径向基函数神经网络的自适应滑模控制方法,实现了参数辨识,使系统输出能渐近跟踪目标轨迹,进而抑制了系统混沌.研究表明,该方法控制时间短、逼近误差小,而且有效地消除了抖振,具有实时控制、鲁棒性高等特点.     

基于MLP实现水轮机适应式PID调节策略

提出一种基于ＭＬＰ模型实现适应式ＰＩＤ控制的策略．该策略不需要被控对象的精确模型，以经典的ＰＩＤ为基础，用神经网络实现，在给定评价函数下进行自学习．把它应用于单机运行的水轮机组频率扰动和负荷扰动仿真试验中，结果表明该策略对于被控系统的严重非线性有很好的适应性和鲁棒性     

基于神经网络的不稳定时滞对象控制

针对过程控制工业中的一类不稳定时滞对象存在的难以稳定、鲁棒性差、对输入的变化和扰动十分敏感的问题,采用了基于神经网络的双自由度控制结构.在利用内环控制器镇定对象并且提高系统反应速度、减轻输出的振荡的同时,结合Guillermo等提出的比例-积分-微分(PID)参数镇定区域理论优化设计外环BP神经网络控制器的学习范围、学习方式和初始参数,改善系统设定值跟踪和扰动抑制的性能,提高系统鲁棒性.仿真结果表明,即使在建模有误差的情况下,该控制结构仍能比传统双自由度PID控制有更好的控制效果和鲁棒性.     

基于MLP实现水轮机适应式PID调节策略

提出一种基于ＭＬＰ模型实现适应式ＰＩＤ控制策略，该策略不需要被控对象的精确模型，以经典的ＰＩＤ为基础，用神经网络实现，在给定评价函数下进行自学习，把它应用于单机运行的水轮机组频率扰动和负荷扰动仿真试验中，结果表明该策略对于被控系统的严重非线性有很好的适应性和鲁棒性。     

不确定分数阶同步发电机混沌系统的滑模自适应控制及参数辨识

考虑了一种带有周期性负荷扰动和电磁功率扰动的同步发电机系统模型.基于分数阶稳定性原理,对分数阶系统的动力学特性做了仿真分析.针对系统内部参数和扰动幅值的不确定,利用径向基函数神经网络的万能逼近特性改进滑模控制方法,设计了一种基于径向基函数的自适应滑模控制器,实现参数辨识,使系统输出能渐近跟踪目标轨迹,进而抑制分数阶系统混沌振荡.研究表明,该方法控制时间短、逼近误差小,而且有效地消除了抖振,具有实时控制、鲁棒性高等特点.     

基于BP网络的非线性广义预测学习控制器

本文提出了一种基于ＢＰ神经网络的非线性义预测学习控制器，它由一个ＢＰ网络构成。在整个学习与控制过程中，首先根据被控对象的输出与ＢＰ的学习输出之间的误差来修改网络的权值，以逐步建立被控对象的合理的多步预报模型；然后，根据网络的多步预报输出序列与设定值序列的偏差修改控制律。     

基于神经网络逆模型的污水pH值内模控制策略

针对污水处理中和反应过程pH值控制具有强干扰和模型参数易变等特点，利用内模控制方法的设定值响应和干扰响应之间相互独立的优点，提出一种基于内模控制和神经网络逆模型相结合的pH值优化控制策略。通过在系统中插入低通滤波器，并采用RBF神经网络在线辨识被控对象的逆模型，提高污水处理pH值控制的鲁棒性和抗干扰能力，有效解决中和反应pH值控制过程中模型参数易变的问题。MATLAB仿真结果表明：与常规PID控制和不带滤波器的神经内模控制策略相比，提出的优化控制策略超调量最多降低17.4%，调节时间最多减少113.6 s，有效提高了系统鲁棒性和抗干扰能力。工程应用表明：使用所提策略后，pH值控制偏差在±0.2以内，系统的控制精度和稳定性显著提高。     

机器人液压驱动器神经网络自适应最优控制

为了有效地控制液压非线性系统,提出基于RBF神经网络的自适应最优控制系统,应用于机器人液压驱动器.首先,建立了液压系统的动力学模型;然后,输入幅值和频率连续变化的信号,应用卡尔曼滤波器估计液压系统状态,进而计算出模型参数,对模型参数进行分组用于训练RBF神经网络;接着,对不同组参数求平均作为参考点,用RBF神经网络学习最优控制器反馈增益随系统参数的变化规律;最后,训练完成的神经网络根据卡尔曼滤波器参数估计值在线预测并调节控制器增益.经实验验证,该控制系统调节时间和跟踪误差仅为普通线性二次型最优控制器的1/2和1/3左右.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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-