模糊神经网络在短期电力负荷预报中的应用

提出了一种用于短期电力负荷预报的模糊神经网络方法,该方法可以直接由模糊信息预测出未来一天或一周的各小时负荷,文中通过实际算例验证了所提模型和方法的有效性。     

基于趋势组合的知期电力负荷预测模型

在运用神经网络进行短期电力负荷预测中，天气是影响负荷的重要因素。为了更好地捕捉天气对负荷的影响，文中提出了一种基于神经网络的趋势组合短期负荷预测思想和模型，将短期负荷与天气变量的内在关系分解为3个不同的趋势分量，即周趋势分量、日趋势分量和小时趋势分量，每一个趋势分量分别用一个神经网络模型捕获，趋势分量的预测结果再用一个神经网络模型进行组合，从而得到最终的预测值，分别用改进的和传统的模型预测一周的小时负荷，结果表明，这种神经网络模型能取得更好的预测精度。     

一种经验模态分解与深度神经网络协作的短时电力负荷预测方法

为整体预测未来电力负荷变化趋势,提出一种基于经验模态分解和深度神经网络协作的短时电力负荷预测方法.首先为削弱原始负荷序列的非平稳特性,利用经验模态分解算法对原始负荷序列进行分解,得到各时序分量.在此基础上,构建各分量的深度神经网络预测模型,将分量的预测结果进行重构得到短时电力负荷预测曲线.利用某电厂短时负荷数据对模型的预测效果进行验证,得到其预测结果的平均绝对误差、均方根误差、平均绝对百分比误差分别为402.951 8、588.945 1、0.042 6.对比仿真进一步表明,同等条件下,基于经验模态分解和深度神经网络协作的短时电力负荷预测方法相较于单一的深度神经网络预测方法,在效果上精度更高,可用于对短时电力负荷的预测.     

基于季节ARIMA模型的电力负荷建模与预报

电力负荷是影响电网寿命和可靠度的一个重要因素，将季节ARIMA模型引入电力负荷的建模及预报，为电力资源分配的宏观调控及电网改造提供了一种可靠的方法和途径，文中用频谱分析的方法检验电力负荷的季节性并求出一个周期；介绍了具有一个周期的季节ARIMA模型的一般表达方式，并给出进行建模及预报的一般过程，以天津市华苑小区的电力负荷为例，进行了季节ARIMA模型的建模及预报。     

模拟电力市场的负荷模型研究

电力市场模拟是研究电力市场的重要方法。在模拟电力市场中负荷模型的建立是一项基础性工作。负荷预报、负荷特性、负荷的价格弹性等均是需要研究的问题。     

基于MVMD-CapSA-DBN的工业多元负荷分类研究

针对多元电力负荷数据时间序列非平稳性、时序相关性和非线性等特性，为掌握电力负荷的变化规律和发展趋势，实现对电力负荷的科学管理，将工业多元负荷有功功率作为原始数据，提出MVMD-CapSA-DBN负荷分类模型.首先，利用改进停止准则的变分模态分解(Variational Mode Decomposition, VMD)将数据分解，得到较为平稳的多个数据分量；之后，提取各分量能量值作为特征；最后，将0～1标准化的数据作为特征向量，输入经卷尾猴搜索算法(Capuchin Search Algorithm, CapSA)优化参数后的深度置信网络(Deep Belief Nets, DBN)信号分类.实验证明，可实现对工业多元负荷数据的有效分类，整体准确率在88.89%左右，部分负荷分类准确率可达100%.     

注意力机制下的EMD-GRU短期电力负荷预测

为进一步提高短期电力负荷预测精度,构建一种基于注意力机制的经验模态分解(EMD)和门控循环单元(GRU)混合模型,对时间序列的短期负荷进行预测.首先,对负荷序列进行EMD,将数据重构成多个分量;再通过GRU提取各分量中时序数据的潜藏特征;经注意力机制突出关键特征后,分别对各分量进行预测;最后,将各分量的预测结果叠加,得到最终预测值.仿真结果表明:相对于BP网络模型、支持向量机(SVR)模型、GRU网络模型和EMD-GRU模型,基于EMD-GRU-Attention的混合预测模型能取得更高的预测精度,有效地提高短期电力负荷预测精度.     

电力负荷的混沌预测方法

借助混沌分析理论介绍了电力负荷时间序列的混沌性识别技术,给出了一种基于混沌负荷序列的预测方法－基于相空间轨迹演化模式的预报模型。该方法具有预测精度高、计算速度快的优点,在短期负荷预测中可获得相当满意的结果。     

基于EEMD和极限学习机的短期电力负荷预测模型

以集成经验模式分解(EEMD)与极限学习机(ELM)为理论基础,提出了将其有机结合进行短期电力负荷预测的方法。首先运用EEMD对短期负荷时间序列进行自适应分解,在此基础上针对分解后不同分量的变化特点,建立相对应的ELM模型进行预测,进而将各分量的预测结果重构以得到最终预测结果。通过实例分析表明该模型的预测精度要优于单极限学习机模型、单支持向量机模型和神经网络模型,同时也验证了该模型应用于短期负荷预测的有效性和可行性。     

电力负荷的混沌预测方法

借助混沌分析理论介绍了电力负荷时间序列的混沌性识别技术,给出了一种基于混沌负荷序列的预测方法--基于相空间轨迹演化模式的预报模型,该方法具有预测精度高、计算速度快的优点,在短期负荷预测中可获得相当满意的结果.     

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.     

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