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1.
在役桥梁承载力模糊可靠性的马尔科夫预测   总被引:5,自引:1,他引:5  
基于模糊评价和马尔科夫过程,研究了在役桥梁承载力可靠度的时变规律。根据模糊评价理论,确定桥梁承载力状况分布向量,引入马尔科夫过程方法,构造结构状态转移概率矩阵。借鉴时间-空间转换思想,提出一种基于逆阵的改进方法用于计算转移概率矩阵,并给出利用桥梁当前承载力状况分布向量修正转移概率矩阵的方法。针对新建桥梁、在役桥梁以及考虑加固的桥梁分别给出其承载力可靠度分布向量预测公式,并提出承载力预测指标。算例表明,该方法可实现桥梁承载力的可靠度预测。  相似文献   

2.
以等效天线噪声系数(Fa)作为表征参数,介绍了城市无线电噪声的测量原理,给出了南京地区测量结果及其分布规律,给出了不同类型地区的噪声-频率回归预测方程,分析了噪声与过往汽车数的关系。  相似文献   

3.
利用变分法建立了砂型热传导方程,给出了计算砂型温度分布与膨润土烧损率分布的有限元耦合算法,并用该算法进行了数值模拟,模拟结果与实验结果一致,说明此算法具有良好的精度,可用于砂型中膨润土的定量预测.  相似文献   

4.
在道路交通噪声随机点声源预测的研究基础上,根据地下停车库车辆进出的特点,提出分时从而瓣不同车辆类型的随机点声源模型。该模型通过计算机模拟给出按时段分布的预测值,与实测值进行比较后发现,模型预测精度较好,比较符合实际情况。  相似文献   

5.
预测井筒压力及温度分布的机理模型   总被引:1,自引:0,他引:1  
基于质量、动量、能量守恒原理及传统学理论,建立了预测井筒流体压力、温度分布的综合数学模型,采用四阶龙格库塔法迭代求解,可同时 预测井筒中的压力和温度分布。给出了实例,以井底温度为基准分别按线性模型和机理模型求出了井筒内温度分布,并对二者进行了比较。比较结果表明机理模型更符合实际。同时可以看出,按两个模型求出的井口温度存在较大差异。  相似文献   

6.
讨论了一类特殊矩阵变量DLM的观测误差方差阵Vt为未知常数矩阵情况下的分布,并给出了修正递推及其预测公式。  相似文献   

7.
储层构造裂缝数值模拟技术   总被引:16,自引:0,他引:16  
数值模拟技术是对储层构造裂缝进行定量预测确定构造裂缝空间分布的一种有效方法。文中给出了构造裂缝定量预测的数值模拟技术的基本原理和实施方法。该项技术是根据构造变形反演研究区域的边界条件及地质模型用有限元方法进行正演计算,确定出研究区的应力场,再结合岩石破裂准则确定裂缝的空间分布。  相似文献   

8.
本文研究了船舶动力装置排气系统的红外辐射分布情况,在计及各向同性参与性气体的情况下,建立了红外场预测的数学模型.与国外文献给出的实测结果相比,本文结果合理可信.文中给出的模型对合理设计舰船排气系统,减少红外辐射密度,提高战区舰船生存能力具有参考价值.  相似文献   

9.
本文直接按采样间隔非均匀的情况研究了一次和二次线性增长模型,并分别就观测误差方差V_t_i已知和未知常数两种情况给出了它们的先验分布、预测分布和后验分布的修正递推算法。  相似文献   

10.
在小样本的情况下,仅利用数理统计方法进行预测是不太适合的。在此先应用粗糙集的相关知识来确定影响电信网络质量的主要因素,然后运用贝叶斯理论将统计推断建立在后验分布的基础上,并给出了小样本试验数据的电信网络质量的预测。  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.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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