共查询到17条相似文献,搜索用时 78 毫秒
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根据业务流的自相似性提出了一种新颖的信道分配算法。该算法首先根据流的自相似性,估计网络中的节点的业务量。然后,根据业务量多少确定占用信道的优先级。业务量大的节点可以优先占用信道。这样,解决了“热点”信道资源紧张的问题。同时,算法对“非热点”的吞吐量影响很小。理论分析证明,这种算法可以有效提高网络吞吐量。仿真结果表明,运用这种算法,网络的吞吐量比最小干扰固定信道分配算法和最小干扰混合信道分配算法可分别提高70%和40%。 相似文献
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《中国计量学院学报》2021,(1):33-39
目的:动态流量计量性能是评价流量仪表的重要指标之一,但目前对于动态流量发生装置以及评价方法仍缺少相关研究;本文提出一种利用临界流喷嘴的限流特性,结合往复式柱塞持续输出可控流量的动态流量发生装置。方法:在AMESim仿真环境对实验系统进行建模,计算获取动态流量输出对应的柱塞缸轨迹曲线,由电子凸轮控制伺服驱动的柱塞缸动态调节喷嘴上游压力,进而实现动态流量的输出,通过往复式柱塞的交替运行实现流量的持续输出。结果:装置能够实现不同频率、幅值组合的正弦气体流量平滑输出,限于柱塞的运行速度,动态流量的输出频率最高约为0.2 Hz[幅值(0.084 8±0.000 5) g/s]。结论:基于往复式柱塞与临界流喷嘴的动态流量输出方案可行,后续可进一步开展动态流量评价方法研究,并针对流量仪表进行动态测试。 相似文献
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为缓解P2P应用的广泛流行给网络服务提供商(ISP)骨干网络带来的流量压力,进行了P2P缓存部署研究,以避免不合理的缓存部署影响缓存性能发挥和造成缓存投入浪费.首先在综合考虑骨干网络拓扑、内容热度变化和缓存状态更新等信息的基础上建立了基于骨干流量的缓存部署模型,然后定义流量距离因子辅助部署算法设计,并给出了一种基于流量距离因子的P2P缓存选址与容量分配(LSCA)算法,最终通过缓存位置和缓存容量的联合优化设计,充分发挥缓存性能,降低骨干网络P2P流量负载.仿真实验结果表明,针对典型的H&S型、Ladder型骨干网络拓扑,LSCA算法与已有部署算法相比均具有更好的性能.应用LSCA算法后,平均链路使用率比已有算法Degree低14%~21%,比已有算法Centrality低9% ~ 12%;平均传输跳数比Degree算法低18% ~29%,比Centrality算法低11% ~20%. 相似文献
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使用混合高斯隐马尔可夫模型对序列图像中像素强度进行建模,从而获得序列图像的背景像素值。实验表明,采用这种方法初始化视频序列的背景模型,具有较好的抗噪声性、鲁棒性和环境适应性。 相似文献
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相较于车流相对稳定的高速公路而言,城市交通流因上下班高峰、红绿灯、交叉路口等影响,具有明显的波动性。现有噪声预测模式中,声源辐射模型采用小时流量及设计速度作为独立变量,车速与车流量没有关联,仅适用于测量常年平均声级,不能正确反映城市道路噪声的动态变化特征。文章对交通流模型进行了调查,以行车速度与车流密度制约关系为基础,结合道路车辆的物理模型及声源辐射模型,建立以车流密度为变量的噪声源动态声源辐射计算模型,描述城市道路交通噪声辐射声级随车流密度的动态变化特征,与已有模型进行对比并通过实测,验证了新模型能更好地反映城市道路车辆声源辐射声级的变化情况。 相似文献
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With the rapid development of Internet, it is increasingly convenient to obtain real-time traffic condition information, which has greatly stimulated the improvement of urban traffic guidance. Traffic conditions are generally divided into four grades in the existing network platform, which are expressed in different colours. The understanding of traffic condition is still at the level of abstract senses. Therefore, it is difficult to grasp the characteristics of urban traffic. To this end, a new idea is proposed in this paper, and the new idea is to study the urban traffic characteristics based on real-time traffic condition information extraction with image identification technology. With this method, we can not only quantify the abstract traffic condition information, but also solve the loss of traffic condition information. In addition, an instance is analysed in this paper, it shows that it can provide references for urban traffic organization management very well. 相似文献
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Agility is the competitive advantage in the global manufacturing environment. It is believed that agility can be realised by networked manufacturing resource optimisation deployment. However, this is a challenge to us now. To solve this question, logical manufacturing unit and logical manufacturing process are proposed to decompose and model the networked manufacturing task, and networked manufacturing resources are organised and modelled based on physical manufacturing unit. During the deployment of manufacturing resources to the task, many factors should be taken into consideration. Of these, manufacturing cost, time and quality are the most important factors. In this paper, before these factors are considered, networked manufacturing resources pre-deployment is carried out to find the candidate manufacturing resources on the basis of manufacturing abilities. Then, resources optimisation deployment is modelled as a multi-objectives optimisation. This optimisation problem is solved based on genetic algorithm after transforming the multi-objectives optimisation problem to a single objectives optimisation problem. Although we may not find the optimal solution for the problem by genetic algorithm, the better and feasible solution is produced. Thus, this algorithm is efficient and can be applicable to practical problem. At last, an illustrative example is presented to show the application of the proposed algorithm. 相似文献
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针对声呐小目标检测由于水下环境复杂、目标回波信号弱等因素造成虚警率和误检率较高的问题,文章提出基于背景抑制和改进直线分割检测(Line Segment Detection, LSD)的检测算法。首先对原始声呐数据截取序列片段,构建多周期累积历程图,凸显运动目标轨迹线特征;其次设计边缘滤波算子,有效滤除部分背景噪声,并结合投影变换进行线特征增强,不仅实现了断裂直线重连,还抑制了剩余噪声;然后基于图像金字塔改进了多尺度LSD直线分割检测算法,有效缓解了过检测问题,大幅增加了直线平均长度;最后为了合并冗余检测信息,利用运动轨迹时空一致性特征设计后处理模块,提高了检测定位精度。通过多组无人遥控潜水器(Remotely Operated Vehicle, ROV)、潜水员、空心球靶小目标序列的湖试、海试数据的定量与可视化结果定性分析,实验结果显示,文中算法与传统LSD相比,误检率和漏检率分别降低了11.2和3.9个百分点,定位误差下降了1.495个像素。结果表明,文中所提算法大幅提高了声呐小目标检测精度,为后续水下目标识别、跟踪等任务奠定重要基础。 相似文献
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E. Ertugrul Karsak 《国际生产研究杂志》2013,51(3):723-738
The decision-makers have been experiencing difficulties in determining the most suitable robot alternative due to the increase in number of robots and the diversity in their application areas. A robust decision framework for robot selection should consider multiple and conflicting criteria and the dependencies among them. This paper introduces a decision model for robot selection based on quality function deployment (QFD) and fuzzy linear regression. The proposed approach benefits from the fact that QFD focuses on delivering value by taking into account the customer requirements and then by deploying this information throughout the development process, and applies this perspective to robot selection. Fuzzy linear regression is considered as an alternative decision aid for robot selection problems where imprecise relationships among system parameters exist. An example robot selection problem is presented to illustrate the proposed decision-making approach. 相似文献