排序方式: 共有153条查询结果,搜索用时 15 毫秒
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为了在分布式存储的大规模数据图上进行快速图模式匹配,提出利用局部评估的分布式图模式匹配算法。各计算节点并行地执行本地匹配;协调器节点收集局部匹配结果、计算边界点的匹配状态并发送给相应的计算节点;计算节点根据边界点的匹配状态确定与边界点相连的节点的匹配情况;协调器节点组合得出最大匹配集。实验结果表明:与已有的分布式图模式匹配算法相比,dis GPM-PE算法都能够在不显著增加通信量的前提下避免数据片段间的依赖关系对执行时间的影响,从而减少图模式匹配的时间。 相似文献
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Ride-hailing platforms such as Uber, Lyft, and DiDi have achieved explosive growth and reshaped urban transportation. The theory and technologies behind these platforms have become one of the most active research topics in the fields of economics, operations research, computer science, and transportation engineering. In particular, advanced matching and dynamic pricing (DP) algorithms—the two key levers in ride-hailing—have received tremendous attention from the research community and are continuously being designed and implemented at industrial scales by ride-hailing platforms. We provide a review of matching and DP techniques in ride-hailing, and show that they are critical for providing an experience with low waiting time for both riders and drivers. Then we link the two levers together by studying a pool-matching mechanism called dynamic waiting (DW) that varies rider waiting and walking before dispatch, which is inspired by a recent carpooling product Express Pool from Uber. We show using data from Uber that by jointly optimizing DP and DW, price variability can be mitigated, while increasing capacity utilization, trip throughput, and welfare. We also highlight several key practical challenges and directions of future research from a practitioner's perspective. 相似文献
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针对宽带单脉冲雷达实测数据三维成像结果难以直观表示的问题,研究了平面视觉形态表示方法。所谓平面视觉形态,是指用设想的人眼沿着雷达波束方向观测得到的目标结构向适当平面的投影。为获得波束依赖平面视觉形态表示,给出了从实测数据中计算雷达波束方向的方法并从目标尺寸准确估计的角度分析了获取雷达波束方向的必要性,在确定波束方向的基础上,根据投影平面确定新的坐标系,并给出了从雷达观测坐标系到新坐标系的坐标旋转方法。给出了某民航飞机实测数据三维成像处理结果在雷达观测坐标系中的投影表示和新坐标系中的平面视觉形态表示,通过两种表示的对比分析,显示了平面视觉形态表示对特征提取的价值。 相似文献
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对海战场综合态势进行态势评估和威胁分析是信息融合系统的最高层级,态势评估结果将对指挥员的指挥决策起到非常重要的作用。根据海军作战理论分析了海战场态势的表示方法,并基于模板方法设计了一种战场当前态势与模板数据库中态势进行匹配的算法。该算法特别适用于高层推理如态势或威胁评估。 相似文献
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模拟计算了新型紫外光学晶体K2A l2B2O7的Ⅰ类、Ⅱ类倍频的相位匹配角、有效非线性系数,得到了其倍频的最短极限基频波波长和最大有效非线性系数,得到了其Ⅰ类、Ⅱ类倍频的走离角、允许角和允许波长的理论曲线。从理论上证明了K2A l2B2O7晶体是优质的新型紫外非线性光学晶体。 相似文献
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This article introduces the Doubly Stochastic Sequential Assignment Problem (DSSAP), an extension of the Sequential Stochastic Assignment Problem (SSAP), where sequentially arriving tasks are assigned to workers with random success rates. A given number of tasks arrive sequentially, each with a random value coming from a known distribution. On a task arrival, it must be assigned to one of the available workers, each with a random success rate coming from a known distribution. Optimal assignment policies are proposed for DSSAP under various assumptions on the random success rates. The optimal assignment algorithm for the general case of DSSAP, where workers have distinct success rate distribution, has an exponential running time. An approximation algorithm that achieves a fraction of the maximum total expected reward in a polynomial time is proposed. The results are illustrated by several numerical experiments. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 124–137, 2016 相似文献
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为了能对提高高斯色噪声中正弦信号的检测能力,提出了二阶自相关和四阶累积量预处理的信号相位匹配检测法.仿真结果表明,高斯色噪声中四阶累积量预处理的信号相位匹配检测法的检测性能接近于高斯白噪声下匹配滤波器,优于二阶自相关的信号相位匹配检测法的检测性能,更优于的信号相位匹配的最小二乘检测器. 相似文献