大型结构系统可靠性分析方法研究

结构系统的可靠性评估是结构设计的一个重要研究内容,而极限状态函数的建立是进行可靠性评估的基础.但是,大型结构系统的极限状态函数极为复杂,响应面法用简单的多项式进行模拟的精度较低,导致误差较大.文章提出用神经网络替代多项式来拟合复杂的极限状态函数,形成所谓的神经网络响应面.然后,基于塑性极限理论,文中提出了不依赖于失效模式的极限状态函数表达形式及采用ICP对该极限状态函数进行计算的方法.最后,依照拟合得到的神经网络响应面,给出了大型结构系统失效概率的方法.通过两个算例计算并和其它方法进行比较,表明该方法的计算精度较高,而计算时间大大降低.     

Part 2. Beyond single-outcome models: Decompositions of aggregate and disaggregate road safety risk

The second part of the state-of-the-art focuses on the development of the founders' double streams explaining single-outcome indicators (probability of accidents and fatalities, respectively) by fixed form regression, as outlined in the Part 1. Following Page (1997, pp. 67–122, 2001) and others, we use as turning point of the evolution of both aggregate and discrete approaches the DRAG-1 model of 1984, itself based on aggregate data, which introduced four key innovations in principle applicable to both streams.     

基于PDA的外场数据采集系统的研究与设计

介绍了基于PDA的外场数据采集系统的研究与设计.系统是在.NET精简框架基础上开发的,并在PDA上实现了数据录入、数据库管理、与远程SQL Server数据库数据同步的功能,同时举出设计实例.     

A model and optimization-based heuristic for the operational aircraft maintenance routing problem

This paper investigates the Operational Aircraft Maintenance Routing Problem (OAMRP). Given a set of flights for a specific homogeneous fleet type, this short-term planning problem requires building feasible aircraft routes that cover each flight exactly once and that satisfy maintenance requirements. Basically, these requirements enforce an aircraft to undergo a planned maintenance at a specified station before accumulating a maximum number of flying hours. This stage is significant to airline companies as it directly impacts the fleet availability, safety, and profitability. The contribution of this paper is twofold. First, we elucidate the complexity status of the OAMRP and we propose an exact mixed-integer programming model that includes a polynomial number of variables and constraints. Furthermore, we propose a graph reduction procedure and valid inequalities that aim at improving the model solvability. Second, we propose a very large-scale neighborhood search algorithm along with a procedure for computing tight lower bounds. We present the results of extensive computational experiments that were carried out on real-world flight networks and attest to the efficacy of the proposed exact and heuristic approaches. In particular, we provide evidence that the exact model delivers optimal solutions for instances with up to 354 flights and 8 aircraft, and that the heuristic approach consistently delivers high-quality solutions while requiring short CPU times.     

Remarks on the Riesz Separation Property of the Linear Span of Positive Compact Operators

It is proven that there exists a Dedekind complete Banach lattice E such that the linear spans/f （E） and IV （E） of positive compact and positive weakly compact operators on E fails to possess the Riesz separation property.     

成都地铁密实砂卵石地层工程地质特性及施工方法浅析

地层的工程地质特性直接影响到支护参数及施工方法的选择。文章结合成都地铁工程实践,介绍了成都砂卵石地层的降水效应;通过对监测数据的分析,反映在CD法和台阶法两种不同施工方法条件下,地层变形及内力变化情况,为制定合理的施工方案提供借鉴和参考。     

新型沥青路面压实机械分析

分析了一种新型沥青路面压实机械（HIPAC）的特点，该机采用前后两条履带来代替通常的钢轮，对热沥青路面进行压实。度用表明它可较早对热沥青路面进行压实，有利于提高沥青路面的压实度和平整度，这是履带应用的创新。     

外部静水压力作用下完好和损伤环肋圆柱壳极限强度计算公式

  目的  重点推导在静水压力下完好和损伤的钢质环肋圆柱壳极限强度预测公式。考虑的损伤场景可代表海上环肋圆柱壳结构（如潜艇、半潜式平台、桅杆以及作为浮式海上风力涡轮机底座的浮柱）的碰撞事故。  方法  验证数值模拟和分析技术,对6种小型环肋圆柱壳模型进行试验。首先,采用刀口压头跌落试验分析4种圆柱模型的损坏情况,然后将所有模型置于静水压力下进行测试,以评估完好和损坏情况下的极限强度。通过改变设计变量,对实际设计的全尺寸环肋圆柱壳进行严格的参数化研究,最后根据参数化研究结果推导出预测损坏环肋圆柱壳剩余强度的简单计算公式。  结果  计算结果与试验结果和有限元分析结果的准确性和可靠性比较结果显示,在所有载荷情况下,吻合均较好。  结论  所做研究对海上结构物环肋圆柱壳的设计和使用极限状态评估具有一定的参考价值。     

三种摊铺机摊铺的沥青混凝土路面平整度,密实度比较

通过对ＡＢＧ４１１、ＶＯＧＥＬＥ１８００和ＢＫ４５０三种摊铺机所摊铺的沥青混凝土路面平整度、密实度的检测，分析得出了三处机型各自适合铺筑的路面结构类型。