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71.
铁路信号安全关键软件的组合测试序列集约简 总被引:2,自引:2,他引:0
针对现有铁路信号系统安全关键软件t-路组合测试序列生成方法在处理大规模输入时产生冗余测试序列,导致测试执行成本较高的问题,提出了一种基于贪婪-粒子群混合优化算法的t-路组合测试序列集约简方法,用于降低序列集的执行成本. 首先,以执行成本最低为约简目标,建立针对t-路组合测试序列集约简的优化模型;然后,在保证测试序列集逻辑覆盖特性的基础上,采用贪婪-粒子群混合优化算法求解模型,计算约简后的测试序列集;最后,以ZPW-2000轨道电路接收器软件作为研究对象,以其生成的2-路组合测试序列集为例开展约简验证. 结果表明,所提方法在保证2-路组合覆盖和逻辑覆盖的前提下,对单个序列集的执行成本约简幅度最高达到98.33%,对序列集总的执行成本约简幅度达到36.10%,验证了所提方法的可行性和有效性. 相似文献
72.
The rate equations and the power evolution equations based on excited state absorption (ESA) and cooperative upconversion (CUC) of high concentration erbium-doped yttrium aluminum garnet (YAG) transparent ceramic waveguide amplifier are set up to analyze the effects of the pump power, active ion concentration and waveguide length on the amplifier gain and noise figure (NF). The numerical analysis predicts that with a pump power of 100mW, an active ion concentration of 1.0×1026 ion/m3 and a waveguide length of 3 cm, a small-signal gain of 30 dB and an NF of 5 dB can be achieved in the micro-chip amplifier. 相似文献
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Time-series samples of settling particles were collected in the water column of Gaoping (formerly spelled Kaoping) Submarine Canyon (KPSC) with two sediment traps on taut-line moorings deployed at two different depths (60 and 280 m) between May 26 and June 27, 2004. Average total polycyclic aromatic hydrocarbon (PAH) concentrations of upper and lower trap array samples were 310 ± 61 ng g− 1 dw (range: 200–440) and 240 ± 36 ng g− 1 dw (range: 180–290), respectively. Principal component analysis results suggest that PAH sources in the trap-collected particles included diesel vehicle/coal burning, diagenetic sources, and petroleum release. PAH downward fluxes based on settling particles were estimated to be 12–44 μg m− 2 d− 1. These values are higher than those reported in the literature for most coastal areas. During the sampling period, both traps were significantly tilted by tidal current and fluctuated vertically. The upper traps experienced greater vertical movements, thus their particle characteristics (e.g., POC, particle mass, and fine particle fraction) varied more than those of the lower traps. Hourly depth variations of the tilted sediment trap array were echoed by the corresponding total PAH concentrations. Moreover, the PAH composition of the collected particles was related to the flow direction and speed. These observations suggest that PAHs can be used as an effective chemical tracer for the transport of terrestrial and marine particulates in a complex aquatic environment like Gaoping (Kaoping) Submarine Canyon. 相似文献
75.
对在编制绞缆筒系列图册的过程中,如何在轴强度、键强度、绞缆筒强度、缆绳强度,额定拉力、轮毂长度、绞缆简直径及长度、毛坯通用等诸多因素同时满足的条件下,进行系列设计作了探讨。 相似文献
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本文在南方某海港工程港池航道工程设计中引入BIM正向设计,利用CIVIL 3D建立了地形曲面和地质曲面模型,建立采样线,对地形曲面、设计曲面、地质曲面进行采样;用断面法进行疏浚工程量计算,用程序自带网格施工图及其他软件等多种方法进行校核以验证计算准确性;通过材质定义,计算不同土类疏浚量并在断面图中表示;在设计完成后,按... 相似文献
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主要介绍了DPZ-440型高速配碴整形车走行齿轮箱的研制及关键技术,重点阐述了其结构特点、工作原理及试验结果。 相似文献
79.
结合两座铁路连续梁桥的工程设计,基于反应谱法对连续梁桥下部结构的地震力计算方法进行了对比分析,旨在得出规范简化算法在连续梁中的适用性。对规范简化算法及有限元全桥模型计算方法的参数取值、影响因素及存在问题进行了探讨,在模型误差很小的前提下对比分析了多桥计算结果,得出以下主要结论:(1)主墩墩高接近的连续梁桥纵向地震力计算可采用规范简化算法,固定墩结果偏保守,活动墩结果略小;横向地震力需采用有限元全桥模型进行计算。(2)主墩墩高差异较大的连续梁桥,规范简化算法误差太大。 相似文献
80.
In most metropolitan areas, an emergency evacuation may require a potentially large number of pedestrians to walk some distance to access their passenger cars or resort to transit systems. In this process, the massive number of pedestrians may place a tremendous burden on vehicles in the roadway network, especially at critical intersections. Thus, the effective road enforcement of the vehicle and pedestrian flows and the proper coordination between these two flows at critical intersections during a multimodal evacuation process is a critical issue in evacuation planning. This article presents an integrated linear model for the design of optimized flow plans for massive mixed pedestrian–vehicle flows within an evacuation zone. The optimized flow can also be used to generate signal timing plans at critical intersections. In addition, the linear nature of the model can circumvent the computational burden to apply in large-scale networks. An illustrating example of the evacuation around the M&T Bank Stadium in downtown Baltimore, MD, is presented and used to demonstrate the model's capability to address the complex interactions between vehicle and pedestrian flows within an evacuation zone. Results of simulation experiments verify the applicability of our model to a real-world scenario and further indicate that accounting for such conflicting movements will yield more reliable estimation of an evacuation's required clearance time. 相似文献