共查询到19条相似文献,搜索用时 46 毫秒
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用超声波测液体密度时,测量声反射系数是重点.提出一种将半波层反射模型简化后,利用相对稳态幅度测量声压反射系数的方法.将一个较薄固体作为半波层置于被测液体中,两侧对称地放置超声波换能器,换能器一个工作在脉冲回波模式,另一个工作在接收模式.调整信号频率使半波层和被测液体交界面的多重反射波达到最大程度干涉,此时被测液体与半波层之间的声反射系数只与两个换能器在稳态下的回波信号幅度比值有关.因此测得换能器的稳态回波信号幅度比,即可得到声反射系数.此方法简化了原来的半波层反射模型,采取对称布局,利用相对稳态幅度法,简化了理论推导过程,降低了测量上的精度要求.最后文章通过实验验证了方法的正确性. 相似文献
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目前,对量子状态估计的算法大都采用离线批处理的方式进行,但离线量子态估计的方法对演化的量子系统难以实时估计。为了解决这一问题,提出一种在线优化算法,用于从具有测量随机噪声的量子系统中,通过连续弱测量估计该自由演化量子系统的状态密度。该算法基于在线邻近梯度法和交替方向乘子法提出,通过1、2、3和4位量子系统的仿真实验,验证了该算法计算高效,对测量随机噪声具有更高的鲁棒性。 相似文献
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为了对武器中的惯性测量组合实施监视与诊断,提出了一套实时在线的故障诊断系统;该系统利用TEAMS-RT与LabVIEW软件和多信号模型建模,实时采集测试点的信号并进行分析,得出惯性测量组合的工作状态;最后通过Simulink模拟产生故障,对整个系统实行检验,结果表明系统正确地推断出故障;所设计的系统,具有在线、实时的特点,可在惯性测量组合的工作过程中及时发现并隔离故障. 相似文献
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一种软测量模型在线校正方法及应用 总被引:1,自引:0,他引:1
提出了一种软测量模型在线校正方法,该方法把变量之间相关性强弱的思想引入软测量模型校正中,根据变量相关性的强弱程度和性质来确定系数修正量的大小,提高了模型测量的实时性和灵活性,并将其成功应用于电石生产比电阻的软测量中. 相似文献
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一种新型液体密度声传感器研究 总被引:2,自引:1,他引:1
介绍一种新型液体密度声传感器的原理及设计方法,与一般液体密度传感器不同之处是其为数字频率量,具有很高的灵敏度,可实现与计算机的直接连接,计算结果表明,这类传感器的灵敏度可达10^-8g/cm^3,适用于高精度测量,且有广阔的应用前景。 相似文献
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一种基于密度的空间数据流在线聚类算法 总被引:2,自引:0,他引:2
为了解决空间数据流中任意形状簇的聚类问题,提出了一种基于密度的空间数据流在线聚类算法(On-line density-based clustering algorithm for spatial datastream,OLDStream),该算法在先前聚类结果上聚类增量空间数据,仅对新增空间点及其满足核心点条件的邻域数据做局部聚类更新,降低聚类更新的时间复杂度,实现对空间数据流的在线聚类.OLDStream算法具有快速处理大规模空间数据流、实时获取全局任意形状的聚类簇结果、对数据流的输入顺序不敏感、并能发现孤立点数据等优势.在真实数据和合成数据上的综合实验验证了算法的聚类效果、高效率性和较高的可伸缩性,同时实验结果的统计分析显示仅有4%的空间点消耗最坏运行时间,对每个空间点的平均聚类时间约为0.033 ms. 相似文献
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为了克服网络控制系统中随机时延对控制性能产生的影响,提出了基于在线时延测量和一步预测输出(基于在线参数辨识)的随机时延补偿方法。通过对以太网中随机时延的分析,提出一种在以太网中不存在同步时钟的情况下在线测量时延的方法;在在线辨识模型参数基础上,得到对象一步(随机时延小于一个采样周期)预测输出,从而根据测得的时延得到对象由于随机时延而引起的输出量变化;再用变化量加上对象输出量用于控制算法反馈。最后通过基于以太网控制实验平台对液位对象进行控制所得的结果,验证了时延测量方法和随机时延补偿算法的有效性。 相似文献
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In this paper, an initial theory of online learning as online participation is suggested. It is argued that online learner participation (1) is a complex process of taking part and maintaining relations with others, (2) is supported by physical and psychological tools, (3) is not synonymous with talking or writing, and (4) is supported by all kinds of engaging activities. Participation and learning are argued to be inseparable and jointly constituting. The implication of the theory is straightforward: If we want to enhance online learning, we need to enhance online learner participation. 相似文献
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Distributed online optimization and online games have been increasingly researched in the last decade, mostly motivated by their wide applications in sensor networks, robotics (e.g., distributed target tracking and formation control), smart grids, deep learning, and so forth. In these problems, there is a network of agents which interact with each other in a collaborative manner (i.e., distributed online optimization) or noncooperative manner (i.e., online games) through local information exchanges. And the local cost function of each agent is time-varying in dynamic and adversarial environments. At each time, a decision must be made by each agent based on historical information at hand without knowing its future cost functions. For these problems, a comprehensive survey is still lacking. This paper aims to provide a thorough overview of distributed online optimization and online games from the perspective of problem settings, algorithms, communication and computation requirements, and performances. In addition, some potential future directions are also discussed. 相似文献
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This study investigates how differences in the use of online health information and social media affect the use of online health services. We attempt to predict the extent to which the use of social media and online health information prompt individuals to use online health services. We draw upon a combination of sociology and communication studies and integrate relational maintenance assumptions regarding the quality of online social relationships to promote the importance of health empowerment factors–socio-demographic characteristics, internet attitudes and health status models to predict the likelihood of using online health services. The study’s sample consists of 1406 individuals using the Internet, including 633 individuals using the Internet and social media to look for health information. The study’s results provide evidence that (a) online health information empowers most of the examined individuals to use online health services; (b) among all social media only those that offer consulting have a significant effect on the likelihood of using online health services. The implications of these findings support that a conceptual integration of CMC and social media use theories along with health empowerment assumptions, is a promising theoretical framework to test the effectiveness of social media use in prompting use of online health services. The practical applications for health management are highlighted as well. Finding practical and affordable ways to support the use of social media and encourage access to online health information and use of online health services could improve health literacy and self-management of health at the individual level and increase the efficiency in the provision of health services at the institutional level. 相似文献
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为了实现对密度高且变化范围大的材料进行密度定量测量,建立自动密度测量系统,对工业材料的密度与CT数的关系进行研究。根据工业CT检测工件常见密度,选取有代表性的几种均匀材料作为标件,并以铝材料作为参考标准件。通过CT扫描获取不同密度标件对应的CT数。选用一幅CT图像为标定图像,以该图像中空气的CT数为标准,对被测材料的CT数进行修正。采用最小二乘法拟合材料密度与CT数的关系式。实验对塑料、橡胶、玻璃、钛合金、钢、铜等材料的密度进行测试,测量精度小于1%。测量结果基本满足工业材料密度的精度要求。 相似文献
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