改进粒子群优化 BP 神经网络的洪水智能预①测模型研究

该文提出改进的PSO-BP算法在洪水预测应用中建立预测模型.以BP神经网络为基础,提取观测站往年平均径流量作为洪水属性.采用改进的PSO-BP算法对神经网络的各个参数进行优化,最后建立模型应用于流域观测站的洪水预报模型,叙述了PSO粒子群算法和BP神经网络算法,详细阐述粒子群算法优化BP神经网络的权值和阈值,得出最优的BP神经网络预测适应度值.通过实验仿真对比,结果表明此方法预测结果比BP神经网络算法和混沌径向基神经网络模型算法精度更高,提高了预测的效率.     

基于参数优化神经网络的海底油气管道腐蚀泄漏预测

为有效预测海底管道因腐蚀导致的泄漏风险,提出了一种海底管道腐蚀泄漏预测模型,首先采用斯皮尔曼相关系数分析各影响因素间的相关性,随后基于随机森林袋外数据进行各因素的重要性排序,剔除掉相关性较高且重要性较小的因素,利用筛选出的数据建立前馈神经网络和随机森林回归预测模型,并利用粒子群算法对神经网络预测模型的权值、阈值进行了优化,构建粒子群优化下的神经网络预测模型。经分析结果表明：神经网络预测模型在5组随机模型训练中平均绝对误差(MAE)、均方误差(MSE)的平均值分别为1.59、 3.37,均高于随机森林回归预测模型,说明该模型误差较大,但决定系数(R2)较随机森林回归预测模型高0.13,因决定系数越接近于1,模型拟合越好,故随机森林回归预测模型较神经网络预测模型拟合度较差,长期预测误差较高,因此可采用粒子群算法对神经网络进行优化,优化后的模型MAE为0.79,MSE为0.7293,R2为0.9151,可见优化后的神经网络预测模型在保证精度的基础上提高了稳定性,预测效果更优。最后编制了集随机森林回归、神经网络及粒子群优化下的神经网络为一体的多模型管道腐蚀预测软件。为海底管道泄漏风险的精准预测以及高效控制提供了依据,在海洋油气运输安全方面具有重要意义。     

克隆选择粒子群优化BP神经网络电力需求预测

在普通BP算法基础上,引入克隆选择粒子群算法,建立电力需求预测模型.将当期国内生产总值、前期国内生产总值、人口、当期产业结构变化、前期产业结构变化等影响电力需求的因素作为网络输入,电力需求作为网络输出,同时选择合适的隐层节点数,确定模型的网络结构.利用克隆选择粒子群算法反复优化BP网络的权值组合,将优化后的权值作为BP神经网络的初始值,进行BP算法,直至网络达到训练指标.利用近几年相关输入输出变量年度数据,对建立的模型进行电力需求实证预测分析,并同普通BP神经网络预测结果进行对比.结果表明:基于克隆选择粒子群优化的BP神经网络不仅训练速度快,而且误差小,预测精度明显提高,说明该模型对于电力需求预测的有效性.     

基于变异粒子群优化与深度神经网络的航空弹药消耗预测模型

为了提高航空弹药的供应保障效率,将变异粒子群优化(MPSO)融入深度神经网络(DNN),研究航空弹药训练消耗预测问题。通过DNN确定网络各层的最优激活函数,基于MPSO参数寻优得到网络各层最优的权值和阈值,进而构建MPSO与DNN融合的航空弹药训练消耗预测模型。实验研究表明,该文组合预测模型在对5年数据的预测中均方误差为0.000 9,与粒子群优化-深度神经网络(PSO-DNN)模型、DNN模型以及反向传播神经网络(BPNN)模型相比具有更好的预测性能。     

改进思维进化算法优化BP神经网络的瓦斯涌出量预测研究

为了保证煤矿安全开采,并提高煤矿瓦斯涌出量的预测精度,提出了改进思维进化算法优化BP神经网络的模型预测新方法。在思维进化算法中加入精英反向学习策略增加算法的全局搜索能力,在趋同操作中引入粒子群算法避免重复搜索,以此实现对BP神经网络的初始权值和阈值的全局寻优,并通过矿井监测到的各项历史数据进行验证。结果表明：与BP神经网络模型和MEA-BP神经网络模型相比较,该模型的预测精度更高,泛化能力更强。该模型的平均相对变动值为0.00116,平均相对误差为0.81%,均方根误差为0.0576,有效提高了对瓦斯涌出量的预测精度,提升了煤矿安全生产技术。     

基于粒子群优化算法的相关向量机边坡稳定性分析模型

为快速获取边坡稳定性系数,及时对边坡进行稳定性评价,提出一种基于粒子群优化算法(particle swarm optimization,PSO)的相关向量机(relevance vector machine,RVM)边坡稳定性分析模型。该模型通过选取影响边坡稳定性安全系数的6个主要因素,并对这6个主要影响因素产生的30组数据进行拟合训练,利用粒子群算法对相关向量机模型参数进行优化,选取最优参数值,根据这30组训练样本来对剩余4组样本进行精准预测。结果表明：与实际值进行对比,基于PSO-RVM模型预测的平均相对误差仅为5.64%,且建立的PSO-RVM预测模型的边坡稳定性安全系数的平均相对误差均明显优于利用BP(back propogation)神经网络和协调粒子群(coordinated particle swarm optimization,CPSO) -BP模型预测得到的平均相对误差,进一步为边坡稳定性预测及评价提供一种新方法。     

PSO-BP神经网络在露天矿卡车油耗预测中的应用

针对露天矿燃油消耗问题,利用粒子群优化算法对BP网络的权值和偏置进行优化,建立了基于粒子群优化BP神经网络的露天矿卡车油耗量预测网络模型.该方法使用由PSO优化的BP模型来拟合影响露天矿卡车油耗众多因素与油耗值之间的复杂关系.仿真结果表明:模型具有预测精度高、稳定性好等特点,适用于露天矿卡车油耗的预测,在露天矿燃油消耗预测中具一定的实用价值.     

基于粒子群改进BP神经网络的组合预测模型及其应用

针对应用广泛的传统人工智能预测BP(Back propagation)神经网络自身局限以及其在处理中长期复杂预测问题中需要样本数量大、泛化能力弱等不足,提出利用粒子群算法优化BP神经网络的学习算法,在此基础上,利用灰色预测方法和自回归移动平均模型(ARIMA)时序预测对历史数据进行初步预测,对中长期预测中数据趋势项和随机项进行模拟;将初步预测的结果作为改进BP神经网络的输入,在此基础上进行训练和预测,构建基于改进BP网络的组合预测模型.以我国1978-2007年能源需求数据为样本,进行实例分析.结果表明:组合预测模型预测精度较BP神经网络、灰色预测方法和ARIMA预测方法分别提高4.8%,6.1%和5.3%,验证了组合预测方法在中长期预测问题处理中的有效性.     

改进粒子群优化神经网络及其在产品质量建模中的应用

针对传统神经网络优化算法易陷入局部最优值的问题,在标准粒子群算法的基础上,对粒子速度与位置更新策略进行改进,提出一种基于改进粒子群优化算法的BP神经网络建模方法. 使用sinc函数、波士顿住房数据及某钢厂带钢热镀锌生产的实际数据进行验证. 结果表明,与标准的反向传播神经网络和支持向量机相比,基于改进粒子群优化的神经网络模型可以有效提高预测精度.     

基于最小二乘支持向量机的风速组合预测模型

探讨了基于最小二乘支持向量机的组合预测模型在风速短期预测中的可行性.该模型以BP神经网络、RBF神经网络、粒子群BP神经网络3种预测模型的风速预测值作为组合预测模型的输入,实际风速值为输出,利用最小二乘支持向量机回归算法构造风速间的非线性关系,以实现风速多步预测.将该模型的预测性能与BP神经网络组合预测模型、线性组合预测模型进行比较,通过平均绝对误差、误差平方和、平均相对误差3个指标进行评价.结果表明,最小二乘支持向量机预测模型的平均相对误差低于6%,其他误差指标也明显低于其他预测模型.因此,最小二乘支持向量机组合预测模型预测精度不仅高于任一单项预测模型预测精度,而且高于传统的线性组合预测模型与一般BP神经网络组合预测模型.验证了该模型在风速预测中的可行性.     

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.     

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.     

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