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1.
电梯故障时,具有故障特征提取困难和故障类型识别率低的问题。因此,拟提取其振动信号并进行分析,找到故障特征。然而,鉴于其振动信号为非平稳、非高斯且背景噪声较大的信号,给有效辨识造成很大困难,所以,提出应用最优小波包分解和最小二乘支持向量机相结合进行电梯智能故障诊断的方法。借助最优小波包理论,首先提取电梯故障振动信号的能量分布;然后将其能量分布与时域指标相结合,构造故障特征向量;最后,将故障特征向量作为粒子群算法优化最小二乘支持向量机的输入对电梯故障类型进行识别。仿真结果表明,最优小波包理论与最小二乘支持向量机相结合的故障诊断技术发挥了两者的优势,证明了该方法的有效性和实用性。  相似文献   

2.
研究提高滚动轴承故障诊断准确率问题,滚动轴承故障振动信号具有非平稳,造成系统不稳定,针对传统方法难以提取故障信息的不足,提出一种小波包和最小二乘支持向量机的滚动轴承故障诊断方法(WP-LSSVM)。首先采用小波包对滚动轴承振动信号进行降噪处理,消除背景和噪声信息,然后小波包对去噪后振动信号分解并计算能量特征值,最后采用最小二乘支持向量机对能量特征值进行学习,建立滚动轴承故障诊断模型。仿真结果表明,滚动轴承故障诊断训练和测试时间减少,且故障诊断准确率得到提高。  相似文献   

3.
系统地提出了模拟电路的最小二乘小波支持向量机故障诊断方法。从测试点得到各种故障状态下的输出电压信号,对输出电压信号进行小波去噪,对信号进行小波分解获取多尺度的低频系数和高频系数,并对小波系数进行处理从而提取出故障特征量,以此作为学习样本来训练最小二乘小波支持向量机,确定其模拟电路故障诊断的模型。雷达系统电路仿真结果表明了模拟电路的小波变换和最小二乘小波支持向量机故障诊断方法取得了较好的效果。  相似文献   

4.
针对雷达电路板检修困难的问题,提出了基于最优小波包基和最小二乘支持向量机相结合的雷达电路板故障诊断方法。利用小波变换对采样数据进行去噪处理,通过小波包分解选择最优小波包基提取熵值作为故障特征向量,并作为基于最小二乘支持向量机的雷达故障诊断模型的输入向量,经诊断模型输出后,完成雷达电路板故障诊断。基于此方法设计了雷达电路板故障诊断系统,提高了雷达故障诊断的正确性和效率。  相似文献   

5.
最小二乘支持向量机在故障诊断中的应用   总被引:1,自引:0,他引:1  
为了提高机械设备故障诊断的精度,将小波包分析与最小二乘支持向量机进行了有机的结合。首先对故障信号功率谱进行小波分解,简化了故障特征向量的提取。然后提出了一种基于最小二乘支持向量机的故障诊断模型,用二次损失函数取代支持向量机中的不敏感损失函数,将不等式约束条件变为等式约束,从而将二次规划问题转变为线性方程组的求解,用最小二乘法实现了支持向量机算法,并提出对核函数的σ参数进行动态选取,提高了诊断的准确率。仿真结果表明该模型具有较强的非线性处理和抗干扰能力。  相似文献   

6.
基于最小二乘支持向量机的故障诊断方法*   总被引:1,自引:1,他引:1  
提出了一种小波包分析与最小二乘支持向量机相结合的机械设备故障诊断模型.首先对故障信号功率谱进行小波分解,简化了故障特征向量的提取,然后采用最小二乘支持向量机进行故障诊断.在该模型中,用二次损失函数取代支持向量机中的不敏感损失函数,将不等式约束条件变为等式约束,从而将二次规划问题转换为线性方程组的求解,并提出对核函数的σ参数进行动态选取.仿真结果表明:该模型可以取得较高的故障诊断准确率.  相似文献   

7.
基于小波包和AGA-LSSVM模型的滚动轴承故障诊断   总被引:1,自引:0,他引:1  
为了解决滚动轴承故障特征提取和故障类型识别问题,提高诊断准确率,提出了一种基于小波包与自适应遗传算法优化最小二乘支持向量机(AGA-LSSVM)相结合的故障诊断模型.首先由小波包分解与重构获取振动信号中能反映不同故障状态的能量特征向量,其次,由经过自适应遗传算法优化的LSSVM模型对滚动轴承常见故障进行诊断.Matlab运行结果表明,相较于传统LSSVM方法,所采用的方法可靠度较高,可以较好地实现对轴承故障的诊断.  相似文献   

8.
由于结构复杂且缺乏故障样本等原因,往复式压缩机的故障样本及诊断结果存在很强的不确定性。针对典型压缩机气阀振动信号的特点及不同故障机理,研究气阀振动信号的特征参数提取方法。提取工作循环有效值RMS1、气阀关闭段有效值RMS2,以及经两层小波包分解得到的各频带能量比系数E1、E2、E3、E4,组成6维特征向量,并将其作为支持向量机的输入。利用支持向量机适合处理高维数据且在有限样本下具有最优泛化能力的特点,对3种不同气阀状态下的振动信号经时域波形分析和小波包分解后提取的特征参数进行支持向量机学习;建立气阀故障诊断的支持向量机分类模型;利用Libsvm软件包对故障样本进行随机分类测试,并与其他智能诊断方法进行对比。对比结果表明,将支持向量机方法应用于往复式压缩机的气阀故障诊断中具有可行性;在小样本条件下,支持向量机较其他智能诊断方法具有更大的优势。  相似文献   

9.
基于混沌PSO算法优化最小二乘支持向量机实现航空发动机磨损状态监测;通过小波包分解消除润滑油光谱数据的噪声,获取LS-SVM的训练与测试样本;针对最小二乘支持向量机解决大规模数据样本回归问题时所出现的训练时间长、收敛速度慢等缺点,提出了混沌PSO算法优化LS-SVM的模型参数;该方法不仅克服了传统PSO算法早熟、容易陷入局部最小值等缺点,同时显著提高了最小二乘支持向量机的预测能力;最后,将一般LS-SVM和GM(1,1)模型的预测结果与文中预测结果进行对比,该方法构建的模型对测试样本产生的预测误差仅为0.0441,验证了该方法在预测精度上具有明显优势。  相似文献   

10.
由于能量缺失和故障等原因导致无线传感器网络节点无法收集后续数据,为保证数据传输的完整性,应进行后续节点数据预测。目前缺少有效方法实现节点数据预测,针对这一问题提出一种基于小波分析和粒子群优化最小二乘支持向量机(PSO-LSSVM)相结合的数据预测方法。方法中利用小波分解技术将所选的样本集数据进行分解,然后将分解量分别送入最小二乘支持向量机(LS-SVM)模型进行预测,其中LS-SVM预测模型的参数由PSO算法得到,最后,将各个LS-SVM模型得到的预测结果进行小波重构得到完整的预测结果。仿真结果表明:基于小波分析和PSO-LSSVM相结合的无线传感器网络节点数据预测方法能够准确跟踪实际数据趋势,该方法具有较高的预测精度。  相似文献   

11.
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.  相似文献   

12.
European Community policy and the market   总被引:1,自引:0,他引:1  
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.  相似文献   

13.
融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。  相似文献   

14.
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.  相似文献   

15.
This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.  相似文献   

16.
Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  相似文献   

17.
为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.  相似文献   

18.
《计算机科学》2007,34(4):148-148
Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.  相似文献   

19.
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.  相似文献   

20.
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.  相似文献   

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