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1.
针对建筑运行能耗非线性和不确定性强的特点,提出一种基于支持向量机的办公建筑逐时能耗预测方法.采用单变量模型检验法确定模型输入变量,引入网格搜索方法优化模型超参数.使用模型拟合误差的置信区间来描述建筑运行能耗的不确定性.采用实际办公楼案例对所提出的预测方法进行验证.结果表明:网格搜索优化后的模型平均绝对百分比误差(MAPE)降低31.3%,取得更高的模型精度;加入置信区间后不同季节中MAPE均低于1.5%,体现了建筑的运行波动.该方法可为建筑运行诊断及优化提供参考.  相似文献   

2.
对结构进行评估时,常需要利用模型的内插与外推结果,且模型的不确定性也是需要考虑的一个重要因素。针对模型参数空间的内插外推问题,本文基于确定性计算模型并联合多次试验结果,计算得到预测误差的不确定性,接着对预测误差的均值与标准差进行函数拟合,并且考虑函数拟合带来的不确定性,通过双层抽样分析得到预测误差的置信区间,再叠加上预测点确定性计算结果进而得到预测结果的置信区间。最后通过不同拧紧力矩下某根部柔性悬臂梁的内插与外推应用检验了该方法的有效性。  相似文献   

3.
为应对交通系统的随机特性,提出一种考虑不确定性的单交叉口信号配时方法。首先应用季节性自回归平均移动-广义自回归条件异方差(seasonal autoregressive integrated moving average-generalized autoregressive conditional heteroskedasticity,SARIMA-GARCH)模型计算交叉口交通流的不确定性,然后根据得到的交通流不确定性特征,参考Webster模型,计算交叉口的信号配时参数,得到考虑交通流不确定性的单交叉口信号配时方案。最后,以南京市一交叉口为研究对象,应用实际数据,计算得到17种不同交通不确定性水平下的单交叉口配时参数,并采用Paramics仿真软件分析了各信号配时方案的性能,验证了所提方法的有效性。  相似文献   

4.
针对传输线加工中材料及结构参数随机不确定性对传输性能影响的问题,提出了一种计算随机系数传输线电报方程的多项式混沌(PC)展开方法。利用正交多项式混沌基函数,该方法首先将传输线电报方程中的随机等效集总参数、传输线电压及电流响应进行展开;其次利用Galerkin法,将随机系数的电报方程问题转化为关于电压、电流正交多项式展开系数的确定性扩阶方程组问题,并结合传输线边界条件可计算电压、电流的展开系数,进而获得电压、电流及传递函数的均值、方差和概率密度分布。随机参数微带传输线的仿真结果表明:低频时导带宽度对微带线的传输性能影响较大,高频时介电常数对其传输性能影响较大;在满足计算精度要求的同时,PC展开方法具有比传统蒙特卡罗(MC)方法更高的计算效率,计算耗时仅约为MC方法的1/500。  相似文献   

5.
针对裂隙岩体的力学参数选取问题,提出了一种两阶段评价方法.通过裂隙岩体力学参数的三维空间分布情况,评价其各向同性与各向异性状态,对两类情况采用不同的计算模型处理;采用Kolmogorov-Smirnov(K-S)检验法对力学参数的概率分布模型进行假设检验,对检验合格的试验数据分布进行置信区间选取,在给定的置信区间内获取计算参数.在某地下硐室工程中运用该方法进行了开挖模拟计算,计算位移与实测位移吻合较好.  相似文献   

6.
在贝叶斯偏差信息(DIC)准则下,研究了一组大型英语测试的二级反应数据在传统的项目反应模型、随机效应题组反应模型以及带有题组判别参数的题组反应模型之间的模型选择问题以及题目参数和应试者能力参数的估计问题.首先,基于Gibbs抽样程序得到的各个模型参数的MCMC样本,计算出了各个模型的DIC函数值,然后经过比较,确定带有题组判别参数的题组反应模型是该组数据较优的拟合模型,最后基于带有题组判别参数的题组反应模型,研究了该项测试的题目参数和应试者的能力参数的后验期望估计以及这些参数的95%的等尾置信区间,所得结果在合理范围内.  相似文献   

7.
为解决具有多元不同类型输出的仿真模型校准问题,提出一种基于优化和元模型的仿真模型校准方法.首先提出一种基于双层嵌套拉丁超立方抽样(LHS)的不确定性参数传播方法,获得系统同时含有认知和固有不确定性时的输出;其次,给出一种基于数据特征的仿真输出一致性度量方法,实现仿真多元异类输出的一致性度量;进而,利用随机Kriging模型拟合认知不确定性抽样样本与仿真输出一致性度量结果的元模型,并在该元模型上通过遗传算法实现校准过程.最后,通过实例验证了本文所提方法的有效性.   相似文献   

8.
基于GLUE方法的流域水文模型的不确定性分析   总被引:10,自引:0,他引:10  
以东江流域中的星丰流域为研究对象,采用GLUE方法探讨了TOPMODEL模型在水文预报中的不确定性.研究结果表明,模型中的参数m、T0和RV较为敏感,它们的微小改变都将影响模拟结果,而参数SR0不太敏感.从两场次洪水的流量过程线可看出,模拟得到的流量过程线的上、下边界并不能完全包含实测流量过程线,总有一些实测流量落在90%的置信区间之外,说明TOPMODEL模型并不能完全模拟出该流域的流量过程,这正是由于模型的不确定性而引起的.  相似文献   

9.
为解决分布式参数非点源污染(IMPULSE)模型不确定性分析中采样量和计算量过大的问题,在Bayes概率理论基础上,构建了基于Sobol序列的GLUE算法,用来描述多种扰动因素共同作用下的全局参数不确定性,从而对模型预测能力进行全面评价。将该方法应用于IMPULSE模型,对分布式参数的全局进行不确定性分析。结果表明:该模型结构优良,具有良好的预测能力,对空间不确定性有较高的预测稳定性和鲁棒性,可以满足实际流域污染模拟需要。  相似文献   

10.
综合分析了现行确定性土壤环境质量评价中的不足,将Monte-Carlo模拟引入地累积指数模型中,并进一步通过数据的挖掘和对土壤中各重金属的生态风险差异的考量,构建了基于不确定性理论的土壤环境质量评价法.将所建方法应用于实例区域,分别构建重金属的实测含量参数和其对应背景值参数的概率分布模型,设定模拟中最大实验量为1 000,置信区间为95%,抽样方法为拉丁超立方(Latin hypercube sampling),得到基于不确定性理论的土壤环境质量评价结果:评价区域土壤中各重金属的污染排序为Cd>Ni>Zn>Cu>Cr,其中,Cd隶属于严重污染等级的概率高达98.1%;Ni和Zn有着明显的空间分布差异,并且属于严重污染的概率也分别达84.5%和87%;Cr和Cu的污染等级相对较低.而后,将所得结果与现行的确定性模型评价结果进行了对比分析,结果表明:所建基于不确定性的评价模型具有更好的评级分辨力,并可更全面、真实地表征该区域土壤重金属的污染特征和概率风险水平.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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-  相似文献   

19.
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-  相似文献   

20.
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  相似文献   

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