The building evacuation problem with shared information

In this article, the Building Evacuation Problem with Shared Information (BEPSI) is formulated as a mixed integer linear program, where the objective is to determine the set of routes along which to send evacuees (supply) from multiple locations throughout a building (sources) to the exits (sinks) such that the total time until all evacuees reach the exits is minimized. The formulation explicitly incorporates the constraints of shared information in providing online instructions to evacuees, ensuring that evacuees departing from an intermediate or source location at a mutual point in time receive common instructions. Arc travel time and capacity, as well as supply at the nodes, are permitted to vary with time and capacity is assumed to be recaptured over time. The BEPSI is shown to be NP‐hard. An exact technique based on Benders decomposition is proposed for its solution. Computational results from numerical experiments on a real‐world network representing a four‐story building are given. Results of experiments employing Benders cuts generated in solving a given problem instance as initial cuts in addressing an updated problem instance are also provided. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

天地预警系统与机敏传感信息网

建立高效的天地预警系统对于赢得现代立体战争的胜利有着极其重要的意义。探讨了天地预警系统与机敏传感信息网 (Sm art Sensor Web)的构成 ,结合我国的部分研究现状 ,较详细地阐述了设计与构造天地预警系统所需解决的若干关键技术问题。     

热交联法制备低含氧量碳化硅纤维初步研究

通过对低预氧化程度的聚碳硅烷 (PCS)纤维进行热交联处理 ,降低SiC纤维中的氧含量 ,经过二步烧成法制备出机械性能及高温耐氧化性能优良的连续SiC纤维。通过IR、XRD、SEM、元素分析仪等分析手段系统研究了研究了热交联碳化硅纤维的热交联处理的工艺条件、烧成工艺 ,研究了热交联碳化硅纤维的组成、微观结构及其与纤维的力学性能、高温抗氧化性能的关系     

反馈系统强镇定的区间算法

反馈系统强镇定不改变受控系统的传递零点 ,而受控系统的传递零点影响反馈系统跟踪参考信号和扰动抑制等能力 ;反馈系统可否强镇定还与两个受控系统是否可同时镇定有密切关系 .给出了判定和计算受控系统强镇定的一种新的算法———区间算法 .这种算法是一种大范围求解方法 ,能同时求出受控系统的全部零点 .     

Capacity expansion with lead times and autocorrelated random demand

The combination of uncertain demand and lead times for installing capacity creates the risk of shortage during the lead time, which may have serious consequences for a service provider. This paper analyzes a model of capacity expansion with autocorrelated random demand and a fixed lead time for adding capacity. To provide a specified level of service, a discrete time expansion timing policy uses a forecast error‐adjusted minimum threshold level of excess capacity position to trigger an expansion. Under this timing policy, the expansion cost can be minimized by solving a deterministic dynamic program. We study the effects of demand characteristics and the lead time length on the capacity threshold. Autocorrelation acts similarly to randomness in hastening expansions but has a smaller impact, especially when lead times are short. However, the failure either to recognize autocorrelation or to accurately estimate its extent can cause substantial policy errors. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

一种胆碱酯酶贮存寿命的预测方法

用差热分析 (DTA)和等温加速老化法 ,测定了用生物化学方法检测有机磷、氨基甲酸酯类农药或毒剂的试剂———胆碱酯酶的贮存寿命。获得了所测定的该种胆碱酯酶的贮存寿命与贮存温度之间的关系式。这种测定方法简便快捷、实用可靠。     

基于 ∆TOA 和方位角测量辅以间歇高度信息的双基地定位跟踪技术

本文讨论了双基地雷达系统中一种以收站△TOA和方位角测量为基础并辅以发射站传送的间歇高度信息的运动目标三维定位跟踪算法,详细分析了该技术的定位原理。在电子对抗条件下,发射站数据往往难以连续传送到接收站加以融合,因此有必要对间断传送的数据加以利用的方法进行研究。本文通过典型目标航迹的计算机仿真对该算法的性能做了评估。由于这种融合方法在双基地研究领域尚属初探,因此有待于在今后的研究中加以完善。     

高速核在高温热平衡等离子体中的非平衡弛豫过程对热核反应率参数的影响

高速核入射到高温热平衡等离子体背景中,由于入射核动能远大于背景等离体中带电粒子之平均动能,入射核在与背景等离子体达到热平衡之前,会存在一段逐渐损失能量的非平衡弛豫过程。本文以高速氘核入射到高温氘化锂等离子体为例,在计及氘核的这种非平衡弛豫过程时,给出了一种计算热核反应D(t,n)~4He之反应率参数的方法。氘核在弛豫过程中的能量损失考虑了氘核与各种带电粒子的库仑散射过程,其能量损失率采用快速带电粒子的慢化理论来计算;氘与背景等离子体中的原子核发生的核反应过程,考虑了非平衡状态下束靶机制的D(t,n)~4He反应和热平衡状态下的D(t.n)~4He反应。在暂未考虑核散射的情况下,计算结果表明,当等离子体温度在7.5KeV～20KeV范围内变化时,氘核的非平衡弛豫过程对热平衡状态下D(t,n)~4He反应率参数的修正因子大致在1.0062～1.0943范围内变动,且温度越高,修正因子越小。计算还表明,当温度一定时,修正因子随等离子体中粒子的数密度变化不明显。     

强脉冲 CO2 激光与靶的相互作用

在真空背景下的实验表明,当微秒量级的强脉冲激光与靶材相互作用时,由于靶材的升华,激光维持爆震波依然存在。爆震波产生的压缩波传入靶内,该应力波的作用是材料破坏的重要因素。而强脉冲激光引起的汽化反冲压力、热应力和烧蚀破坏也是不可忽视的因素。实验还表明,在真空背景下维持爆震波足以将后续激光屏蔽。     

应变率和绝热软化对空腔膨胀影响的数值模拟

采用数值模拟的方法研究金属材料球形空腔膨胀的空腔面径向应力与膨胀速度关系.理想弹塑性模型和幂次硬化模型的模拟结果与理论解吻合得非常好,验证了该方法的有效性.在此基础上研究了应变率和绝热软化效应对空腔面径向力和膨胀速度的影响.结果表明,综合考虑应变率和热效应的侵深预测结果与试验值吻合得很好,只考虑应变率而不计热效应会高估...