道路网络分层的快速路径诱导算法

路径诱导在现代交通和部队机动过程中具有重要应用,传统路径诱导算法(如Dijkstra算法)具有很高的计算复杂度和搜索空间,所规划路径仅仅是数学意义上的最短路径,很难满足实际道路交通导航诱导要求.为了降低路径诱导算法的搜索空间,同时使得规划的结果更能体现驾驶人员行车偏好,提出一种基于道路网络分层的快速路径诱导算法,在利用道路网络中道路的不同等级特性对路网进行分层处理基础上,通过限制算法搜索区域达到快速路径规划的目的.实验结果表明,该算法解算出导航路径中大部分是由快速路段组成,能很好地满足驾驶人员的选路偏好,路径搜索时间和搜索空间也大大减少.     

基于GeoHash索引的A算法优化

A*(A Star)算法进行最短路径计算时,一般采用曼哈顿函数作为最优邻接点的评估标准,在算法执行的过程中,需要对每一步每个邻接点进行计算,判断出当前最优邻接点,然后迭代执行下一步,在数据量较大的情况下,算法的时间复杂度呈几何增长.使用GeoHash索引算法代替曼哈顿函数作为评估标准,在有地理坐标信息的网络拓扑中进行最短路径查找,直接以GeoHash编码索引值作为判断标准,进行快速查找.GeoHash值是经纬度经过一系列编码转换后的实际值,能够拓扑网格中的属性值,减少算法的计算时间,优化算法的时间复杂度.提高A*算法在道路规划、运行调度、无人驾驶路径分析时的最短路径计算时间,可增加实际应用广泛性.     

网络势能合作博弈——一种求最优路径问题的新方法

最优路径算法广泛应用于物流规划、自动驾驶等实际场景。当交通网络复杂度增大时,算法的效率尤为重要。设计了基于网络势能合作博弈模型的分布式算法,将道路网络模拟成电路,利用电路中电阻最小路径电流最大的原理求解最优路径问题。该模型通过分量迭代,计算出每个节点的势能值,进而计算出节点间的电流值,确定从起点到终点的最大电流路径为最优路径。通过实验验证了模型的可靠性,其计算效率远高于Dijkstra算法。     

动态目标的Field D~*算法及路径的提取计算

FieldD*算法计算的路径消耗较优并较为平滑,但该方法的计算量很大,尤其是在对动态目标的规划时,计算时间无法满足实际要求。针对该缺陷,在对FieldD*计算原理分析的基础上,提出了在目标是动态的情况下,只进行前目标与新目标的路径规划,并对FieldD*计算所得路径消耗只进行局部修改的动态规划算法,该动态算法可以有效减少计算量。将得到的路径消耗值应用到路径的提取算法中,路径提取算法针对路径消耗的不同情况下,提出不同的路径提取方法,并最终得出总体路径消耗最优的路径。在以栅格法建立的数字海图中进行仿真验证,该动态计算和路径提取算法与D*算法相比,计算所得的路径更为平滑,路径的总体消耗也更少,缺点是所需计算时间略长。     

部队铁路输送路径选择算法研究

根据部队铁路输送要求和铁路路网特点,设计了基于辅助信息的双向A＊路径搜索算法,采用二次读入边数据方法表示路网,利用前向关：联边存储结构存储路网,应用经验知识限制算法的搜索区域,通过使用常量系数β提高了启发函数的信息性。实验结果表明,算法的改进是有效和实用的。     

针对应急救援路径规划的一种改进蚁群算法

针对不返回起始点、多个待救援点的应急救援路径规划问题,提出了一种应急救援路径规划的改进蚁群算法,设计了一种新的路径构造方法,为蚁群算法求解该类问题打下了基础。为提高收敛性,改进了信息素更新规则,构造了一种与蚁群算法有效结合的局部搜索算法,提高了算法快速寻优的能力。仿真结果表明:改进蚁群算法能够快速找到一条从救援中心到多个待救援点的优化路径,且收敛速度和最短路径较同类算法更优。     

基于禁忌退火算法的巡航导弹航迹规划

针对巡航导弹航迹规划这个复杂的优化问题,一个禁忌退火混合优化算法被提出.首先,该算法是以基本模拟退火算法为基础.其次,为了加快该模拟退火算法的收敛速度,在恶化解的接受判断过程中,增加了一定动态的约束条件.最后,为了使最优解能够跳出局部最优的陷阱,使用了一个动态的禁忌表.仿真结果验证了该禁忌退火混合优化算法能够取得目标函数更优的航迹规划路径,从而有效提高巡航导弹的作战效能.     

蚁群遗传融合算法在移动机器人路径规划中的应用

针对移动机器人路径规划的特点,把智能算法引入到机器人路径规划中。而单一蚁群算法和遗传算法,存在收敛速度慢、效率低或容易陷入局部最优等缺陷,对蚁群算法进行改进,提出一种改进蚁群遗传算法的融合方案,并把该方案应用到移动机器人路径规划中,在栅格环境下进行仿真测试,仿真结果表明该方案能有效提高最优路径的搜索效率,整体性能优于蚁群或遗传单一智能算法。     

时变道路网最短路径算法的研究

道路或区域通行限制在日常交通和部队兵力机动过程中普遍存在。通行限制情况下的最短路径问题属于时变道路网最短路径研究的范畴,对时变道路网最短路径算法及算法效率的研究有着广泛而现实的意义。重点讨论了道路网的模型描述、时变道路网拓扑结构的构建技术,最短路径算法的高效实现等内容,并给出了该算法的应用实例。试验结果显示,该算法有效可行。     

战时侦察车最优路径规划算法

针对侦察车路径优化同题,提出了一种改进的遗传算法,基于该算法设计了一种在战时情况下能使侦察车快速、安全、高效地进入侦察阵地的最优路径算法,并编制了侦察车路径优化软件,为战时侦察车最优路径规划同题提供了一种解决方法.     

On a search for a moving target

We consider the problem of searching for a target that moves in discrete time and space according to some Markovian process. At each time, a searcher attempts to detect the target. If the searcher's action at each time is such as to maximize his chances of immediate detection, we call his strategy “myopic.” We provide a computationally useful necessary condition for optimality, and use it to provide an example wherein the myopic strategy is not optimal.     

谈核电站火灾自动报警系统的特殊配置

结合核电站火灾危险的特殊性,阐述了核电站常规岛中网控楼、蓄电池室、汽轮机厂房、电缆隧道、输变电变压器等建筑的火灾自动报警系统设备的特殊配置及选用特点,以发挥火灾自动报警系统的监控作用。     

Between a rock and a hard place: Europe in a post-INF world

The end of the 1987 Intermediate-range Nuclear Forces (INF) Treaty has the potential to plunge Europe and NATO into deep crisis. Russia’s continued violation coupled with the Donald J. Trump administration’s desire to balance against Moscow and Beijing could force a new missile debate on Europeans. Even though Washington is trying to assuage its allies, the specter of another round of INF missile deployments to Europe is not unrealistic. Meanwhile, NATO’s European members face a dilemma. Some want NATO to resolutely push back against Russia. Others want to avoid a new deployment debate, at almost all costs. The Kremlin will use these cleavages to weaken NATO. If not carefully handled, NATO’s response to the Russian missile buildup could lead to domestic turmoil in a number of European states and render the alliance ineffective for a prolonged period. Europeans need to act now and voice their preferences in the military and diplomatic domains. A number of different military options are available, below the level of deploying new INF missiles in Europe. However, Europeans need to consider trade-offs regarding crisis and arms-race stability. At the same time, it will be up to European capitals to conceptualize a new arms-control framework for the post-INF world, one that takes into account today’s geopolitical realities and the entanglement of modern conventional and nuclear forces. Given the Trump administration’s loathing of arms control, concepts of mutual restraint may well have to wait for the next US administration. In any case, that should not stop Europeans from taking on more responsibility for their own security.     

On a constraint qualification in a nondifferentiable programming problem

A mathematical programming problem with an objective function containing the square root of a positive semidefinite quadratic form has been considered by Mond. In order to use a transposition theorem of Eisenberg, Mond introduces a complicated constraint qualification. In this note we give a simple geometric characterization to this constraint qualification and show that it is implied by the generalized Slater constraint qualification.     

Analysis of a production system in a general configuration

We consider a production system comprising multiple stations (or workshops) such as an entry station, a set of work stations, a central station, and an exit station, which are arranged in a general configuration. A worker (or a vehicle tool) is assigned to each station, who sends a part from the station to the destination station according to the required process path of the part. Any part is allowed to visit a work station more than once if its process path requires. We propose a new control strategy with the push policy for instructing each worker to send a part and the kanban mechanism for controlling the work‐in‐process (WIP) in each work station. As all work stations have limited local buffers, the central station is used for storing blocked parts temporarily. Such a production system is modeled as an open queueing network in a general configuration with a Markovian part sending policy and a machine no blocking mechanism. The queueing network is analytically characterized. Some important performance measures are compared with other control strategies. A semi‐open decomposition approach is applied to the queueing network for computing the blocking probabilities when parts arrive at the work stations. An algorithm is developed based on the semi‐open decomposition approach. Numerical experiments show the quality of the solutions obtained by the algorithm as well as a property of a performance measure. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 128–143, 2001     

铜冶炼炉溜槽上方钢梁温度分布研究

为了对有色冶炼厂房框架钢梁耐火稳定性评估提供条件,根据冶炼铜实际工况建立计算模型,数值研究钢梁温度分布,结果表明:在加热初期,钢梁的平均温度和最高温度不断上升,经历10个升温-降温周期后,钢梁的最高温度稳定在220℃左右。钢梁温度与梁的截面尺寸和形状、梁计算截面位置、溜槽与梁相对位置等众多因素有关。梁与溜槽距离越大,梁截面高度越大,翼缘宽度越小,最高温度与平均温度越低;梁长度大小不影响梁最高温度,但梁长度越大平均温度越低。     

一代名将百世楷模--纪念萧劲光大将诞辰100周年

本文是中共中央军委副主席郭伯雄2003年1月3日在纪念萧劲光同志诞辰100周年座谈会上的讲话。标题为本刊编者所加。     

锁相倍频开关式跟踪滤波器

本文提出一种简单的跟踪滤波器电路,该电路可用于多普勒雷达,主要由开关式带通滤波器和锁相环组成。实验结果表明,它具有捕捉范围宽、捕捉时间短和在噪声背景下有令人满意的性能等特点。     

Experimental investigation of a cook-off temperature in a hot barrel

The experimental investigations of the effect of contact time/temperature on initiating the cook-off using 7.62 mm calibre cartridge cases (CC) were conducted previously. These cartridges were filled with commercial off-the-shelf (COTS) double based (DB) propellant (Bulls Eye) and were loaded in a hot chamber. The thermal explosion temperature is of great significance to both weapon designers and safety inspectors as it provides the operational limit and safe operating temperature. For CC under test, it was found that the cook-off temperatures of this propellant were encountered with the heat transfer profile of the simulated gun barrel between 151.4 °C and 153.4 °C, with a reaction occurring in less than 300 s after the round was chambered. Usefully, each experiment was found to be consistent and repeatable.     

建筑火灾烟气蔓延规律对火灾探测系统的影响

分析了烟在建筑物内部的蔓延规律,讨论了烟气的蔓延规律、气流速度、障碍物及房间高度对火灾探测系统的影响,得出研究火灾烟气蔓延规律对火灾探测系统的可靠性具有重要意义的结论。