oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 2 )

2019 ( 105 )

2018 ( 2260 )

2017 ( 2395 )

Custom range...

Search Results: 1 - 10 of 118864 matches for " 胡启国 "
All listed articles are free for downloading (OA Articles)
Page 1 /118864
Display every page Item
车辆ABS参数自调节模糊PID控制仿真
,任龙
重庆交通大学学报(自然科学版) , 2012, DOI: 10.3969/j.issn.1674-0696.2012.02.39
Abstract: :?通过一个单轮车辆模型对ABS(antilockbrakingsystem)进行数学建模,将模糊控制理论与传统PID控制理论相结合,构造出满意的参数自调节模糊PID控制器;在不同路面下对所建立的汽车ABS数学模型进行仿真,并与传统PID控制下的ABS系统进行比较。仿真结果表明:基于参数自调节模糊PID控制器的ABS系统能实时地对参数进行调节,其制动性能优于PID控制器;无论是在干路面还是在湿路面、冰雪路面下,都能使车轮工作在最佳滑移率附近,缩短制动距离并有效的改善制动时的方向稳定性。
基于群策层次分析法和模糊聚类理论的改进质量功能展开研究
,张鹏
计算机集成制造系统 , 2007,
Abstract: 针对传统质量屋存在的缺陷,在建立质量功能展开总体递阶层次结构的基础上,建立了一种新的质量功能展开递阶质量屋。以此结构为基础进行了用户需求层次的展开,运用模糊聚类动态分类方法对用户需求进行分类,并对基于群策层次分析法递阶质量屋中的参数进行确定。通过实例验证了本文提出方法的有效性、可行性和可操作性。
基于累积损伤模型的多阶段系统可靠性分析路集组合方法
Path Sets Combination Method for Reliability Analysis of Phased-Mission Systems Based on Cumulative Exposure Model

,何金银
- , 2018,
Abstract: 多阶段系统因阶段任务的关联性,元件的共用性,导致系统可靠性建模难度大,求解过程复杂,对此提出基于累积损伤模型的多阶段系统可靠性分析路集组合方法。针对元件跨阶段相关性以及各阶段失效率不同问题,利用元件累积损伤模型,考虑元件历史损伤,求取元件各阶段累积失效分布进行描述。系统路集组合方法利用多阶段系统故障树映射成贝叶斯网络方法建立多阶段系统可靠性模型,通过遍历贝叶斯网络求取各阶段最小路集。针对路集间的相关性以及规模过大问题,采用变量消元法推导出的不交化公式实现路集去相关性与共用元件的条件概率关系缩减最小不交路集规模。再按元件条件概率关系对各阶段最小不交路集进行组合求和。该方法避免了传统贝叶斯网络方法因阶段状态离散过多造成的条件概率表规模大、存储空间需求大、运算量大的问题以及PMS-BDD方法对变量排序有严格要求的限制与难以求解含有多种分布类型元件的系统可靠性问题。对某地球同步轨道卫星进行了多阶段系统可靠性建模与求解,并与PMS-BDD方法相对比,验证了路集组合方法的正确性。
The modeling of phased-mission systems is difficult and the solving process is complex because of the relevance of the phase tasks and the sharing of components existing in different phases or between phases. To solve the problem, based on the cumulative exposure model, the path sets combination method of phased-mission systems is proposed. Aiming at the problem of the cross-stage correlation of components and its different failure rate in each phase, the cumulative exposure model considering the historical damage of components is used to solve by obtaining the cumulative damage distribution of each component in each phase. Firstly, a phased-mission systems reliability model is build by mapping phased-mission system fault trees into a Bayesian network. By traversing the Bayesian network, the minimal path sets of each phase are obtained. Secondly, the disjoint formulas introduced by variable elimination method are used to do the disjoint operation of the minimal path sets of each phase and the conditional probability relations of the common components are used to reduce the minimal path sets scale. Finally, the minimum disjoint path sets of each phase are combined and summed according to the component conditional probability relation. The path sets combination method of phased-mission systems avoids the large conditional probability table, large storage and large computation problems caused by the excessive discrete states in the traditional Bayesian method and the problem that the PMS-BDD method has strict requirements for variable ordering and is difficult to solve the system reliability with multiple failure distribution types of components. In the end, a phased-mission systems reliability modeling and solving is carried out for a geosynchronous orbit satellite, and compared with the PMS-BDD method, which verifies the correctness of the method
Vine Copula模型的失效动态相关机械系统可靠性分析
Reliability Analysis of Failure Dynamic Mechanical System using Vine Copula Model

,周松
- , 2018,
Abstract: 提出机械系统的失效动态相关可靠性可采用动态Vine Copula模型进行描述。采用Vine Copula函数将复杂多失效相关的机械系统可靠性问题转换为对多个二维动态Copula函数进行分析。利用非参数估计算法,提出经验分布函数-局部极大似然两步法估计动态Copula函数中的时变参数,从而建立动态Vine Copula 模型来描述多失效动态相关机械系统的可靠性;并重点对机械系统的串联体系可靠性进行建模与分析,进而对机械系统的可靠度进行求解。最后通过单级减速器系统的算例验证了所述方法的合理性及有效性。
The dynamic reliability of mechanical system failure can be described by dynamic Vine Copula model. The Vine Copula function is used to transform the reliability problems of complex and multiple failures related to the analysis of multiple two-dimensional dynamic Copula functions; using the nonparametric estimation algorithm, the empirical distribution function-local maximum likelihood two-step method is proposed to estimate the time-varying parameters in the dynamic Copula function; next, a dynamic Vine Copula model is established to describe the reliability of multi-failure dynamic related mechanical systems. The study focus on the mechanical system of the series system reliability modeling and analysis, then solve out the reliability of the mechanical system. Finally, an example is given to demonstrate the rationality and validity of the method
A Two-weight Norm Inequality for Singular Integral Operators with Non-smooth Kernel on Spaces of Homogeneous Type
齐型空间上带非光滑核的奇异积分算子的双权不等式

,
数学物理学报(A辑) , 2009,
Abstract: In this paper, a two-weight weak type norm inequality for singular integral operators with non-smooth kernel is established on spaces of homogeneous type. The authors prove that the operators in question are bounded from Lp(X, v) to Lq, ∞( X, u) with 1< p ≤ q <∞, provided that the pair of weights (u, v) verifies an Ap-type condition with an '`Orlicz-bump' on the weight u.
基于人-车-路耦合振动系统的儿童乘坐舒适性
钱凯,,李力克
重庆交通大学学报(自然科学版) , 2013, DOI: 10.3969/j.issn.1674-0696.2013.02.39
Abstract: :?根据拉格朗日原理,建立了基于人-车-路耦合振动的12自由度动力学数学模型;借助MATLAB/Simulink平台,分析车速、路面不平度、汽车前后轮迟滞性及左右轮相干性的特点;构建了随机路面激励时域模型;采用时域和车对儿童头部、臀部振动影响。研究表明:通过提高路面等级及车速可以提高儿童的乘坐舒适性;儿童对5~10Hz的低频及15,23Hz的中频振动最为敏感;适当地降低座椅刚度、提高阻尼及合理地布置座椅位置可以提高儿童的乘坐舒适性。
土钉墙作用机理的非线性分析
,
工业建筑 , 1997, DOI: 10.13204/j.gyjz199711003
Abstract: 采用带两个转动自由度的Goodman单元来模拟土钉墙与土之间的接触作用,推导了它的刚度阵,并用弹塑性有限元法分析了土钉墙与土共同作用机理,给出了土钉墙的设计建议。
改进蚁群算法在系统可靠度最优冗余分配的应用
,小华,吴泳龙
重庆交通大学学报(自然科学版) , 2013, DOI: 10.3969/j.issn.1674-0696.2013.03.40
Abstract: :?针对蚁群算法在解决NP困难时所存在的极易陷入局部最优值和搜索时间过长的问题,在蚁群算法基础上重新设计状态转移规则和信息素更新规则。实验研究表明:改进后的算法可以有效解决最优冗余分配问题,同时可以在相对短的时间内找到问题的最优解。
考虑带裂缝工作的组合梁柱等效刚度计算
周奎,方立新,,
工业建筑 , 2001, DOI: 10.13204/j.gyjz200109019
Abstract: 对带裂缝工作的梁柱杆件,不考虑开裂区混凝土的作用,将构件视为变截面梁柱,并以最简单的阶梯形变截面杆件来考虑。同时考虑了变截面杆件的刚度及横向荷载的二阶效应,最后得出的结果简便而实用,具有一定的应用价值
金湖凹陷阜宁组低熟烃源岩饱和烃组成及其生源探讨
,,王铁冠,钟宁宁
沉积学报 , 1997,
Abstract: 本文应用气相色谱(GC)、色谱—质谱(GC-MS)和线性同位素质谱(GC-C-MS)分析技术对苏北盆地金湖凹陷下第三系阜宁组阜二段低熟烃源岩饱和烃组分及单体烃稳定碳同位素组成进行了深入地研究,发现甾烷类(特别是ααα(20R)-C29甾烷)在饱和烃中含量很高,正构烷烃呈三峰型分布,以nC22或nC20为主峰。最后根据烃源岩有机显微组分和单体烃碳同位素组成特征认为正构烷烃中低碳数(19)和中等碳数(nC19—nC23)正构烷烃可能主要来源于菌藻类,高碳数(>nC23正构烷烃主要来源于高等植物的蜡质;甾烷类(包括高丰度C29甾烷)大部分可能主要由藻类贡献。
Page 1 /118864
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.