基于预报因子聚类分级的日径流预报深度信念模型及应用

径流预报是水库运行调度的重要决策依据,提高入库径流预报精度,对水库优化调度和水资源高效利用具有重要意义.本文提出一种基于大样本数据分级策略的深度信念网络模型(Deep Belief Networks,DBN),以龙羊峡入库径流预报为例,采用Fuzzy C-means(FCM)聚类方法,将总样本训练集分为不同训练样本子集;不同样本子集下,对不同预报因子(只考虑降雨、考虑不同时期的降雨及同时考虑降雨及前期径流),分别建立DBN模型和人工神经网络模型(Artificial Neural Network,ANN),分析样本分级和考虑不同因子情况下不同模型的预报结果.结果表明:与不考虑预报因子分级的预报模型相比,基于时间序列聚类的预报模型显著提高了径流预报的精度;通过FCM聚类,将样本分为3类,考虑降雨及前期径流作为预报因子进行分级时,比只考虑降雨、考虑不同时期的降雨时建立的预报模型的预测精度更高.用该模型进行龙羊峡水库入流日径流预报,提高了预报精度,可为龙羊峡水库调度提供决策支持.     

基于随机效应模型的交叉口事故碰撞类型建模

考虑交叉口不同进口道之间的差异性,在进口道层面对不同碰撞类型事故分别建立随机效应模型,通过在负二项模型中引入随机效应项来考虑交叉口不同进口道之间的空间相关性.模型参数采用全贝叶斯方法进行估计.结果表明:不同碰撞类型事故的影响因素不同,且同一影响因素对不同碰撞类型事故的影响程度也存在显著差异,验证了区分碰撞类型进行事故建模的必要性.随机效应项在各模型中均显著,表明交叉口不同进口道之间事故频率存在显著的空间相关性.     

11自由度非线性车辆平顺性模型的研究及应用

在分析车辆平顺性的基础上,建立了11自由度平顺性分析的模型,在传统模型的基础上增加了座椅,同时考虑了悬架的非线性因素.所建立的模型考虑了车身的俯仰及侧倾,以及座椅对车辆平顺性的影响,使分析模型更加详细和完整.利用变步长积分法得到车身的垂向振动、俯仰振动和侧倾振动加速度,以及4个座椅振动加速度,分析了不同路面、不同行驶速度和不同乘坐位置对车辆平顺性的影响.结果表明,考虑座椅的11自由度平顺性模型的分析结果更符合实际,比直接用车身来衡量平顺性的结果更精确.     

随机控制的HJB方程与证券投资模型

在介绍随机控制基本理论的基础上,给出了不同情形下随机控制模型最优控制存在的HJB方程,并将随机控制理论运用于证券投资问题,建立了两种不同情况下的随机控制模型,即不考虑消费行为的风险投资模型和考虑消费行为的风险投资模型,通过对其HJB方程的分析求解,分别得到了相应的最优控制策略.     

考虑不同利益主体的区域常规与非常规水资源协同配置模型

为了将非常规水资源纳入水资源统一配置体系,同时考虑不同层次决策主体利益,研究考虑不同利益主体的常规与非常规水资源协同配置模型.分别以区域管理者、常规与非常规水资源供水者为上下层模型主体,构建水资源配置双层模型,并考虑决策者的决策空间,应用NSGAⅢ-NSGAⅡ多目标算法进行模型求解.在此基础上,采用TOPSIS法,将本...     

短车道信号控制交叉口通行能力概率模型

针对短车道信号控制交叉口,提出考虑不同流向相互阻塞概率的通行能力计算模型,该模型克服了以往交叉口通行能力计算模型中对交叉口短车道影响考虑不足的缺陷.根据短车道条件下不同交通流的相互阻塞特征,将交叉口短车道分为三类.基于车流到达随机性,考虑相邻周期排队状态的相互作用,将阻塞过程划分为不阻塞、可能阻塞、阻塞后三个阶段,建立了通行能力计算模型.基于实测数据标定后的微观仿真分析表明,相对于HCM(Highway CapacityManual)模型,该模型计算结果能够相对更真实地反映短车道信号控制交叉口通行能力.针对短车道长度、短车道数目,绿信比和周期长度的参数敏感性分析,进一步揭示了在不同流量水平下短车道对交叉口通行能力的影响.     

VDR混合交通流模型的研究

在交通流VDR模型的基础上,考虑不同类型车辆之间存在的性能差异,其启动、刹车时的随机延迟概率是不同的,从而提出了VDR混合交通流模型.通过计算机数值模拟,得到了混合车辆在不同参数下交通流模型的基本图,并对混合交通流的特性进行了分析和讨论.     

以计算机模拟为基础的矿井胶带煤仓系统动态优化模型

在一个快速模拟模型的基础上,结合数学规划理论中的几种不同方法,开发了一个具有内部优化过程的胶带煤仓系统的优化设计模型.在这一模型中,既考虑了煤流的随机波动特性,也考虑了系统的其它动态特征.利用这一模型,可以通过一次计算选出系统中各胶带宽度、速度和各煤仓仓容的最优组合方案.这一模型已应用于中国两个正在设计的大型系统.     

基于供应商经济生产批量的供应链订单分配问题

针对一条由1个占主导地位的制造商和多个供应商组成的二级供应链,考虑供应商生产过程的衰退,建立了生产批量与产品质量之间的关系.综合考虑制造商的采购成本和售后期望损失成本,并根据供应商决策其经济生产批量时考虑因素的不同,建立2种订单分配模型.该模型的约束条件包括供应商产能约束和供应商关系维持约束.通过遗传算法得到2种模型的优化解,并对2种模型进行分析比较.最后,基于联合决策模型对单一供应商的定价策略变动进行了灵敏度分析.     

考虑预应变与烘烤时效的流动应力模型

建立了考虑预应变和烘烤硬化影响的铝合金流动应力模型.对经历过不同大小、方向预应变和不同烘烤处理的A6111铝合金板料做了不同方向的单拉试验.对比各常用流动应力模型拟合效果后选取H-S模型.对试验和拟合数据进行归纳统计,并分析了各主要影响因素对H S模型中拟合参数的影响.此流动应力预测模型可帮助提高汽车碰撞仿真的准确性.     

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