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1.
建立了炮兵装备效能评估模型,首先利用灰色关联分析以及欧氏距离加权法实现了不完备信息表的空值填补;然后引入粗糙集理论对评估指标进行约简;最后利用BP神经网络确定了指标与效能间的关系并与指数模型进行比较,BP神经网络模型的精度明显高于指数模型.  相似文献   

2.
为了弥补现有工业用户能效评估模型及算法存在的不足,按照相关标准规范并兼顾实际可操作性,构建了工业用户能效评估指标体系,建立起基于BP神经网络的工业用户能效评估模型。通过25组数据完成了BP神经网络的训练,获得了达到设定误差的BP神经网络,最后运用5组测试数据验证了该模型的可靠性。测试结果表明:测试数据通过BP神经网络模型得到的评分和采用其它评估方法得到的评分基本吻合,选取的评价指标具有有效性,该评估模型能够有效的对工业用户的能效水平进行评估。  相似文献   

3.
针对在线评测系统中缺少对学习者编程能力的客观反馈和评估指标权重难以确定的问题,建立遗传算法(genetic al-gorithm,GA)优化反向传播(back propagation,BP)(GA-BP)神经网络的编程能力评估模型.通过对在线评测系统的数据进行挖掘,提取编程能力评估指标,采用双参数平衡熵权法和离差最大化法的客观组合赋权方法确定指标权重以及编程能力评估值,将评估值作为GA-BP神经网络的期望输出,并与单一BP神经网络确定的编程能力评估结果进行比较.研究结果表明,利用该模型能够实现对学习者编程能力的评估且评估结果更准确.  相似文献   

4.
给出了基于多元统计—BP神经网络的教学质量评估模型,先采用相关分析、主成分分析对其影响因子作评价和预处理分析,然后以BP神经网络模型作预测,并在Matlab中实现.结果表明,基于多元统计—BP神经网络的教学质量评估模型,既克服了在评估过程中的主观因素,又得到了满意的评估结果,具有广泛的适用性.  相似文献   

5.
针对网络化制造环境下产品设计的特点,分析了客户满意度在产品设计中的重要性.将客户满意度应用到协同设计环境下的协商机制中.按照协同设计环境下产品设计的要求建立了在产品协同设计过程中客户满意度的指标体系,并以此建立了满意度数学模型.采用多Agent技术,建立基于客户满意度的协商Agent模型并分析了协商过程.结合企业实际需求,利用BP神经网络对客户满意度的评估进行了训练和仿真,通过神经网络减少评价过程中的人为因素,提高了评价的可靠性.同时验证了基于BP神经网络的客户满意度协商模型的有效性.  相似文献   

6.
利用动量BP算法改进了BP神经网络的收敛性,建立了过渡段路基沉降预测模型.该模型可克服传统BP神经网络收敛速度慢、易陷入局部最优等的缺点.结合津秦客运专线路桥过渡段路基沉降实测数据,将该优化模型与传统BP神经网络预测模型进行了对比.计算表明,利用动量BP算法改进的神经网络具有较高的预测精度,同时考虑了多个影响因素,因而具有广阔的应用前景.  相似文献   

7.
介绍了BP神经网络的结构和算法,分析了如何将BP神经网络用于机械设备的故障诊断.结合汽轮发电机组的故障特性,建立了汽轮发电机组故障诊断的神经网络模型,并利用该神经网络模型对汽轮发电机组的故障进行了诊断,诊断结果是正确和有效的.  相似文献   

8.
基于BP神经网络的砂土液化影响因素的综合评估   总被引:5,自引:3,他引:5  
为了充分考虑影响砂土液化的多种因素,选取不同的参数组合,建立不同的砂土液化判别BP神经网络模型,编写了饱和砂土液化判别BP神经网络程序SLV,并根据现场实测资料进行计算和分析.结果表明,地震作用是液化的直接原因,砂土处于饱和状态是液化的前提条件,影响液化的主要因素包括标准贯入锤击数、砂土不均匀系数以及地震剪应力比.文中建立的BP神经网络模型具有高度的分类和识别能力,可用于评估砂土液化的影响因素.  相似文献   

9.
小净距2扩4隧道变形规律的BP小波神经预测   总被引:1,自引:0,他引:1  
以泉厦高速扩建工程大帽山隧道为例,通过周边位移和拱顶沉降的监测数据对小净距扩挖隧道的围岩变形规律进行分析.研究表明:小净距2扩4隧道具有和其他隧道不同的变形规律.在此基础上将小波函数引入BP神经网络建立BP小波神经网络模型,对特大断面超小净距隧道2扩4时围岩变形进行预测,并将预测结果与BP神经网络的预测结果进行对比.结果表明:BP小波神经网络模型收敛快、精度高,优于BP神经网络模型,预测的精度达10%以内,满足工程精度要求.  相似文献   

10.
杭州紫之隧道浅埋暗挖北段处于地下水丰富的软弱地层中,施工过程中产生的地表沉降量难以控制,波动范围较大.为了准确评估施工风险,采用BP神经网络对最大地表沉降进行预测.首先对地表沉降的影响因素进行选取和量化,构成样本数据组.然后通过试错法,建立预测精度最高的一般BP神经网络和遗传算法优化的BP神经网络模型,研究发现BP神经网络在预测地表沉降方面效果较好,且使用遗传算法可以进一步提升预测精度.接着探讨了地层渗透性对BP神经网络预测精度的影响,研究发现不考虑地层渗透性会使预测精度大幅下降.最后对BP神经网络模型参数进行了敏感性分析,揭示了预测沉降的变化趋势符合客观变形机理.  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.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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