Influences of different crossing types on dynamic response of underground cavern subjected to ground shock

An intersecting cavern is a common structural form used in underground engineering, and its safety and stability performance directly control the service performance of the whole project. The dynamic re-sponses of the three kinds of crossing type (+-shaped, T-shaped, L-shaped) caverns subjected to ground shock were studied by numerical simulation. The velocity plus force mode boundary setting method was proposed in the coupled static and dynamic analysis of a deep underground cavern. The results show that, among the three types of crossing caverns, the+-shaped cavern is the most significantly affected by the dynamic action, followed by T-shaped, and then L-shaped caverns. The vault settlement, straight wall deformation, vault peak particle velocity, effective plastic strain of surrounding rock, and maximum principal stress and strain at the bottom of the lining of the straight wall increase with the increase of cavern span. The vault settlement, straight wall deformation, effective plastic strain of surrounding rock, and the maximum principal stress and strain at the bottom of lining to the straight wall decrease with the increase of lateral pressure coefficient, and the peak particle velocity at the vault increases. The variation is small compared with the change of cavern span. The influence range of the underground cavern intersection is two cavern diameters from the intersection centre. The bottom of the straight wall at the intersection is the weak part. It is suggested to thicken the support locally to improve the stability of the cavern.     

基于FCM与粗糙集的连续数据知识挖掘方法

对连续数据知识挖掘可采用模糊C均值聚类将其离散化,再应用粗糙集进行约简.文中针对该过程中样本数据离散化后出现多个聚类中心隶属度值较接近的情况,提出了隶属度重叠度的方法来扩展对应离散类别的选取.离散类别确定后再应用粗糙集理论对其进行知识挖掘,可得到连续数据的本质特性.此方法应用于汽轮机轴系振动数据的知识挖掘.与采用最大隶属度确定对应类别的方法相比,该方法不影响对连续数据的知识挖掘,并能真实反映连续数据的特性.     

有色噪声下FIR模型相关辨识精度分析

本文针对离散控制系统的有限脉冲响应（ＦＩＲ）函数模型,研究了在伪随机ｍ序列输入的激励和有色噪声干扰下辨识的精度问题,纠正了参考文献中的错误,得到了有色噪声干扰下ＦＩＲ参数估计精度的显式表达式。同时,给出了辨识精度的下界和上界,分析并得到了达到上下界的条件。文中有实例分析。     

Decomposition-based approximation algorithms for the one-warehouse multi-retailer problem with concave batch order costs

We study the one-warehouse multi-retailer problem under deterministic dynamic demand and concave batch order costs, where order batches have an identical capacity and the order cost function for each facility is concave within the batch. Under appropriate assumptions on holding cost structure, we obtain lower bounds via a decomposition that splits the two-echelon problem into single-facility subproblems, then propose approximation algorithms by judiciously recombining the subproblem solutions. For piecewise linear concave batch order costs with a constant number of slopes we obtain a constant-factor approximation, while for general concave batch costs we propose an approximation within a logarithmic factor of optimality. We also extend some results to subadditive order and/or holding costs.     

Branch‐and‐price‐and‐cut for the manpower routing problem with synchronization constraints

In this article, we propose a branch‐and‐price‐and‐cut (BPC) algorithm to exactly solve the manpower routing problem with synchronization constraints (MRPSC). Compared with the classical vehicle routing problems (VRPs), the defining characteristic of the MRPSC is that multiple workers are required to work together and start at the same time to carry out a job, that is, the routes of the scheduling subjects are dependent. The incorporation of the synchronization constraints increases the difficulty of the MRPSC significantly and makes the existing VRP exact algorithm inapplicable. Although there are many types of valid inequalities for the VRP or its variants, so far we can only adapt the infeasible path elimination inequality and the weak clique inequality to handle the synchronization constraints in our BPC algorithm. The experimental results at the root node of the branch‐and‐bound tree show that the employed inequalities can effectively improve the lower bound of the problem. Compared with ILOG CPLEX, our BPC algorithm managed to find optimal solutions for more test instances within 1 hour. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 138–171, 2016     

HYLTE与TRIP喷管在大功率氟化氘激光器中的应用对比分析

简述了燃烧驱动大功率连续波DF化学激光器的发展现状。比较了HYLTE与TRIP两种喷管的结构参数,总结了两种喷管的性能差异。采用数值模拟手段,参考相关试验数据,计算了典型增益分布对应的共焦非稳腔输出光束模式。从大功率DF激光器研制存在的光斑均匀性和腔镜负载两个难题的角度,结合喷管制造工艺要求,认为HYLTE喷管较TRIP喷管更适用于大功率DF激光器。     

战时铁路运输油料抢收模拟优化

战时,铁路运输油料抢收是一个受到各种随机因素影响的复杂过程,很难采用数学方法建立模型求解。以运筹学的排队论为建模指导思想,采用GPSSW语言对这一动态过程进行模拟,并对模拟结果进行统计分析,结合实际情况采用优化技术对模拟结果作出改进,从而得到最佳的抢收方案。结果表明,该模拟方法适用于解决此类半结构化问题,可为战时铁路运输油料抢收提供有效的决策支持。     

系统与应用相结合 加强科学计算研究

科学计算是计算机学科和应用学科交叉融合的产物。文章阐述了科学计算的内涵和作用,论述了其科学基础和关键技术,及其对高性能计算机技术的挑战,提出了从科学计算应用基础研究和艾级计算机关键技术研究着手,加强科学计算交叉研究和复合型人才培养的思考。     

某型高射机枪机匣校正产生破断的原因分析

某型高射机枪机匣经调质后,在校正时发生破断。采用化学分析和宏微观断口观察等方法,对破断件进行了分析。结果表明,破断件断口上有局部过烧区,且在晶界上形成疏松孔,并伴有严重的氧化。在外力作用下即发生沿晶界脆性破断。     

层次分析法在民用客机项目供应商选择中的应用

本文根据项目评价的一般原则,结合大飞机项目的特点,建立了大飞机项目的评价指标体系,确立了企业能力、服务程度、合作水平等三项指标,设计了大飞机项目供应商选择的程序和方法,并给出了应用范例。