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51.
刘青宜 《自动化与仪器仪表》2014,(2):68-69
引入测量系统分析(MAS)技术,对实验仪器设备进行测评分析,判断仪器是否合格,保障了仪器设备的精确性,并以实验室四架天平为例,检验了此方法的可行性。 相似文献
52.
叶青 《自动化与仪器仪表》2014,(7):190-192
介绍了多声路超声波流量计在明渠中的流量测量原理,并通过多声路时差式超声波流量计在引水明渠上的实例应用对影响流量测量的误差源进行了具体的分析。 相似文献
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Large volume of online review data can reveal consumers’ major interests on domain product, which attracts great research interests from the academic community. Most of the existing works focus on the problems of review summarization, aspect identification or opinion mining from an item’s point of view such as the quality or popularity of products. Considering the fact that users who generate those review texts draw different attentions to product aspects with respect to their own interests, in this article, we aim to learn K users’ interest groups indicated by their review writings. Such K interest groups’ identification can facilitate better understanding of major and potential consumers’ concerns which are crucial for applications like product improvement on customer-oriented design or diverse marketing strategies. Instead of using a traditional text clustering approach, we treat the groupId/clusterId as a hidden variable and use a permutation-based structural topic model called KMM. Through this model, we infer K interest groups’ distribution by discovering not only the frequency of product aspects (Topic Frequency), but also the occurrence priority of respective aspects (Topic Order). They jointly present an informative summarization on the raw review corpus. Our experiment on several real-world review datasets demonstrates a competitive solution. 相似文献
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许多政府或企业网站除展示与本单位密切相关的信息外,往往也集成一些小的功能性的、与用户日常生活密切相关的,类似于提供火车时刻表、天气预报等辅助信息,采用C#利用Web Service提供的编程接口实现了实时天气预报功能,并能根据访问者所在地自动提供其相关的天气信息。 相似文献
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Shenquan Wang Jian Feng Qing Zhao Yulian Jiang 《International Journal of Control, Automation and Systems》2014,12(4):904-914
In this paper, the problem of observer-based control is investigated for networked control systems (NCSs) with probabilistic interval distribution communication delays. In the presence of network-induced delays and packet dropouts in the sensor-to-controller and controller-to-actuator connections, a new model for an observer-based NCS is established, which is then converted to an equivalent linear system with two random time-varying delays satisfying Bernoulli distributions. By utilizing information concerning the probability distribution of the delays and by adopting a tighter bounding technique, less conservative asymptotic mean-square stable sufficient conditions are derived in the form of linear matrix inequalities (LMIs). Numerical examples are provided to demonstrate the effectiveness of the proposed method. 相似文献
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Guangyong Sun Xueguan Song Seokheum Baek Qing Li 《Structural and Multidisciplinary Optimization》2014,49(6):897-913
Deterministic optimization has been successfully applied to a range of design problems involving foam-filled thin-walled structures, and to some extent gained significant confidence for the applications of such structures in automotive, aerospace, transportation and defense industries. However, the conventional deterministic design could become less meaningful or even unacceptable when considering the perturbations of design variables and noises of system parameters. To overcome this drawback, a robust design methodology is presented in this paper to address the effects of parametric uncertainties of foam-filled thin-walled structure on design optimization, in which different sigma criteria are adopted to measure the variations. The Kriging modeling technique is used to construct the corresponding surrogate models of mean and standard deviation for different crashworthiness criteria. A sequential sampling approach is introduced to improve the fitness accuracy of these surrogate models. Finally, a gradient-based sequential quadratic program (SQP) method is employed from 20 different initial points to obtain a quasi-global robust optimum solution. The optimal solutions were verified by using the Monte Carlo simulation. The results show that the presented robust optimization method is fairly effective and efficient, the crashworthiness and robustness of the foam-filled thin-walled structure can be improved significantly. 相似文献
59.
本文以2013年全国大学生电子设计竞赛A题为依据,设计的单相AC-DC变换电路32位的STM32f103作为主控制器,主电路由220V市电经过自耦变压器,隔离变压器降至20-30V交流电,后接全桥整流电路,使电路稳定输出36V直流电,主电路通过硬件电流电压PI闭环控制,双环控制来调节输入的电流和输出电压,输入的交流电压和交流电流通过互感器采到单片机内,程序通过改变产生的正弦波的相位来改变功率因数,从而达到功率因数可调的目的,使设计的电路能包含题目中要求的所有部分,并通过优化而达到题目的要求,在主电路中加入继电器,控制继电器断开从而实现过流保护的功能。 相似文献
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