共查询到19条相似文献,搜索用时 62 毫秒
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经典粗糙集理论只能处理离散数据,不能将其直接应用于实际系统的数据挖掘中.本文引入样本之间的相似性和改进的属性广义区分度的概念,并定义了属性的全局相似性程度,然后利用容差关系对连续数据集直接进行属性约简,避免了数据离散化过程中信息的丢失.最后将其应用于汽轮机组故障诊断系统中,实验结果表明该方法的有效性. 相似文献
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It is well-known that transit-time ultrasonic flowmeters (TTUF) are unsuitable for bubble-contained flows. This paper presents a new online monitoring method based on optical observation, which monitors the functionality of the TTUF in the presence of bubbles in the fluid. The method avoids the unnecessary Emergency Shutdowns (ESD) due to bubble presence in the fluid by bubble detection. The proposed method accomplishes bubble identification through a combination of image processing and wavelet analysis. In addition, a new method is proposed which estimates single bubble size in horizontal pipes using a data fusion approach. 相似文献
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为了改进传统测距方法的不足,本文研制单片机控制的超声波测距仪.该仪器在工业控制、能源勘探及机器人定位等领域具有强度大、方向性好及精度高等特点. 相似文献
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研制了一种新型直线超声电机,首先对其驱动机理进行了探讨,对定子表面质点椭圆运动的形成进行了分析,结合电机输入电压信号的时序阐明了电机工作模态的激发过程;其次对电机结构进行了设计,确定了振子尺寸,组装了一台直线超声电机. 相似文献
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A monitoring network developed to diagnose early faults in power generators is described. Nowadays, the appropriate operation of generators resides in the information provided by the online monitoring system, which is used to implement predictive maintenance for these machines and to provide early warning of potential failures.In this paper, the configuration of the monitoring system and a detailed study of the measured variables related to their physical behaviour within the generators’ operation are presented. The sensors used and the waveform analysis procedures are explained. Additionally, the architecture that constitutes the application programs and their characteristics as a data network is also described. Finally, some results recorded by the system are shown and discussed. 相似文献
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《Measurement》2015
Data envelopment analysis (DEA) is an approach to measure the relative efficiency of a set of decision-making units (DMUs) which uses multiple inputs to produce multiple outputs. In real world situations, due to uncertainty, DEA is sometimes faced with imprecise inputs and/or outputs. Therefore, performance measurement must often be performed under uncertainty conditions. Generally, the performance of DMUs can be evaluated from two perspectives—optimistic and pessimistic. As a result, two different evaluations are obtained for each DMU. In this article, we first obtain the efficiencies of the DMUs under evaluation from both optimistic and pessimistic views. The optimistic view evaluates each DMU with a set of the most desirable weights; the efficiencies measured by the optimistic approach are called optimistic efficiencies. The pessimistic view evaluates each DMU with a set of the most undesirable weights; the efficiencies measured by the pessimistic approach are called pessimistic efficiencies. Then it is shown that the outcomes of these two evaluations are conflicting with each other, being undoubtedly biased, unrealistic, and unconvincing. To overcome this problem, we propose a new measure of overall performance which is used for integrating the measures obtained from optimistic and pessimistic views and we will use it to identify the DMU with the best performance under uncertainty conditions. Also, we propose new fuzzy DEA models that evaluate a DMU from the pessimistic perspective in a fuzzy context. The proposed measure will be shown with two numerical examples, including the selection of a flexible manufacturing system. 相似文献