基于Volterra自适应滤波器的发动机运转噪声预测

摘 要：发动机运转噪声的预测对于减小发动机运转噪声干扰、提高发动机异响故障诊断正确率具有重要意义。基于相空间重构理论,采用三阶Volterra自适应滤波器,提出了两种分别采用双传感器、单传感器的发动机运转噪声建模与预测方法。所提方法有效利用了Volterra级数强大的非线性映射能力,充分考虑了发动机运转噪声内在的循环相关性、周期及相位信息等先验知识。试验结果表明,所提方法具有较好的鲁棒性,其精度可以满足实际应用要求。     

住宅两用燃气壁挂炉设备配置与计算

给出了无市政配套供暖设施的居民冬季采暖的一种解决方法,及生活热水、采暖两用燃气壁挂炉系统的设备配置与计算,探讨了住宅生活热水系统的循环设置,并结合实际工程介绍设备运行特点。     

PLC在型材跑偏检测控制中的应用

本文简要地介绍了型材辊压生产线的工艺流程,提出了一种实用的型材跑偏的检测方法,并给出了实现流程图和可编程控制器的梯形图,通过实验应用证明了该方案的实用性,它保证了生产线运行的安全性和可靠性。     

中波发射系统改造设计与实现

本文结合实际经验,分析并给出了中波发射系统改造中,对运行环境、供配电、信号源、天线阻抗匹配网络等重要环节的改造方案,可供中波发射系统改造作参考。     

水下井口头系统下放工具关键部件设计与分析

水下井口头系统是深海油气钻采必不可少的设备,常规套管挂和密封总成下放工具不能满足现场需要.建立了套管挂和密封总成下放工具力学模型,采用该模型可以直观地描述下放工具受力情况,根据力学模型和分析结果对下放工具进行结构设计.利用ANSYS有限元分析软件对下放工具套管挂携带单元和驱动单元进行接触分析和强度分析.分析结果显示,套...     

节能减排是水泥企业精细运转的核心

将＂节能减排＂作为水泥企业精细运转的核心,有利于产量、质量、运转率、成本指标的提升,是带动实现这些指标的灵魂。要做好节能减排工作,管理者必须转变经营理念;应当明确两个中心：设备能实现完好状态下的高运转率;系统能在稳定条件下以最佳的工艺参数运转。高素质的员工队伍,高性价比的装备,高度均质稳定的原燃料,高水平的仪表自动化,高质量的基本建设是做好节能减排工作的条件。     

VASC/SCL法脱硫装置的试运行情况

介绍了VASC／SCL法煤气脱硫装置的工艺流程、标定结果及存在问题，实践表明，该装置具有操作简单、运行稳定、自动化程度高、作业环境好、硫磺质量好和无三废外排等优点，其脱硫率90％，脱氰率86％，硫磺纯度99．7％。     

变频调速—在印刷机械行业应用前景广阔

本文介绍了印刷机械设备的加工对象及设备的分类，运动特点，变频器的行业应用情况及广阔的应用前景。     

Classification and evaluation of timed running schemas for workflow based on process mining

The system running logs of a workflow contain much information about the behavior and logical structure between activities. In this paper, a mining approach is proposed to discover the structural and temporal model for a workflow from its timed running logs. The mining results are represented in the formalized form of Petri nets extended with two timing factors that allows validation or verification the actual behaviors, especially the temporal constraints between activities. According to the reachability graph of the extended Petri net model mined, all running schemas of a workflow can be generated, which defines the temporal constraints between running activities. By calculating the earliest and latest start time of each activity, the earliest starting and latest existing time of each state in the running schema can be determined. Based on the temporal relations between the timing factors of each running state, the running schemas can be classified into six classes. The effects of the six classes of running schemas on the implementation of the whole workflow are evaluated so as to obtain the best one that can ensure the workflow is finished in the shortest time. The standards for the ideal, reliable and favorable running schemas and their existence conditions are discussed, which can be used to evaluate the running logs and control the future running of a workflow.