析通信线路消防安全管理方面存在的问题

针对我国通信行业与公安消防部门就通信线路和建构筑物之间安全距离规定不统一 ,分析我国通信线路消防安全管理方面存在的问题 ,并提出改进通信线路消防安全管理的建议     

基于多假设跟踪弹道导弹主动段跟踪算法

针对弹道导弹主动段防御中多枚弹道导弹同时跟踪问题,提出了基于多假设思想的主动段跟踪算法.重点阐述了该算法中假设生成、假设概率计算、假设约简以及假设剪枝等环节.从工程实用的角度出发,采用求解一个线性分配问题(LAP)方法得到M个最优假设,大大减少了假设数量,并运用N-scan回溯剪枝方法对假设进行剪枝,确定要输出的航迹,提高了算法的效率和实用性.仿真实验表明,该算法能够对主动段多枚弹道导弹目标准确关联跟踪.     

一类带容量限制的运输问题

考虑一类带容量限制的运输问题.采用构造辅助网络的方法,将运输网络中的每个配送中心均拆分成两个节点,构造出新弧,形成新的网络,把此类运输问题转换为最小费用流问题来解决.并在此基础上,考虑运输网络中配送中心的容量扩张问题.     

边界元角点问题的重节点法分析

应用重节点法处理三维弹性力学角节点问题,采用等参变换插值逼近的方法离散边界积分方程,解决了由于角节点表面力不连续带来的方程求解困难问题。算例分析结果表明,该方法具有操作简单,计算方便,求解结果满足计算精度的要求等优点,尤其在角点存在应力集中场合更具优越性。     

Bi‐objective missile rescheduling for a naval task group with dynamic disruptions

This paper considers the rescheduling of surface‐to‐air missiles (SAMs) for a naval task group (TG), where a set of SAMs have already been scheduled to intercept a set of anti‐ship missiles (ASMs). In missile defense, the initial engagement schedule is developed according to the initial state of the defensive and attacking units. However, unforeseen events may arise during the engagement, creating a dynamic environment to be handled, and making the initial schedule infeasible or inefficient. In this study, the initial engagement schedule of a TG is assumed to be disrupted by the occurrence of a destroyed ASM, the breakdown of a SAM system, or an incoming new target ASM. To produce an updated schedule, a new biobjective mathematical model is formulated that maximizes the no‐leaker probability value for the TG and minimizes the total deviation from the initial schedule. With the problem shown to be NP‐hard, some special cases are presented that can be solved in polynomial time. We solve small size problems by the augmented ? ‐ constraint method and propose heuristic procedures to generate a set of nondominated solutions for larger problems. The results are presented for different size problems and the total effectiveness of the model is evaluated.     

[AXB,GXH]=[C,D]对称最小二乘解及最佳逼近的极小残差法

构造迭代算法研究了矩阵方程[AXB,GXH] = [C,D] ,证明了该算法可经有限步得到方程的对称最小二乘解及其最佳逼近,并给出了相关性质.最后,通过数值例子表明该算法是有效的.     

Reformulating linear programs with transportation constraints—With applications to workforce scheduling

We study linear programming models that contain transportation constraints in their formulation. Typically, these models have a multistage nature and the transportation constraints together with the associated flow variables are used to achieve consistency between consecutive stages. We describe how to reformulate these models by projecting out the flow variables. The reformulation can be more desirable since it has fewer variables and can be solved faster. We apply these ideas to reformulate two well‐known workforce staffing and scheduling problems: the shift scheduling problem and the tour scheduling problem. We also present computational results. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

当前高校教学评估中的问题及对策研究

高校教学评估是高等教育质量保障体系的重要方面,对当前我国高校教学评估中普遍存在的问题应引起足够重视并提出相应的对策。     

一类带配送中心运输问题的容量扩张模型研究

运输问题一般采用表上作业法来解决,考虑一类带配送中心的运输问题,若仍采用表上作业法,会使问题复杂化.文中采用一种构造辅助网络的方法:在运输网络中将每个配送中心均拆分成两个点,连接两点形成新弧,构造出新的网络,并给每条弧赋予参数,将此类运输问题转换为最小费用流模型来解决,可以使问题模型和运算简单化.在此基础上,考虑运输网络中配送中心和边的容量扩张问题.     

Optimizing natural gas pipeline transmission with nonuniform elevation: A new initialization approach

In this paper, we develop an iterative piecewise linear approximation approach with a novel initialization method to solve natural gas pipeline transmission problems with the nonuniform network elevation. Previous approaches, such as energy minimization methods, cannot be applied to solve problems with the nonuniform network elevation because they exclude pressure range constraints, and thus provide solutions far from optimum. We propose a new initialization model that considers pressure range constraints and improves the optimality of the solutions and the computational efficiency. Furthermore, we extend the energy minimization methods and provide the necessary conditions under which the extended methods operate in networks with the nonuniform elevation. We test the performances of the methods with previously reported pipeline networks from the literature, with the open data set GasLib, and with our industrial collaborator. The initialization approach is shown to be more efficient than the method with fixed initial breakpoints. The newly proposed initialization approach generates solutions with a higher accuracy than the extended energy minimization methods, especially in large‐size networks. The proposed method has been applied to natural gas transmission planning by the China National Petroleum Corporation and has brought a direct profit increase of 330 million U.S. dollars in 2015‐2017.