以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。...以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。首先介绍了3L-ANPC变流器拓扑结构中Si C-MOSFET和Si-IGBT器件的2种组合模式及3种调制方式,然后对3L-ANPC变流器拓扑共模噪声传输机理进行分析,基于分析建立了包含寄生参数和噪声源的EMI模型,并推导出每种调制方式下传导路径的阻抗表达式,得到了共模传导路径阻抗特性曲线。最终通过实验验证了3种调制方式下器件混合型3L-ANPC变流器拓扑共模噪声的分析结论。展开更多
For business service workflow,QoS-based services selection can't guarantee whether the composite service satisfies user' s requirement after delivery,because once any service interrupts or quality of service(Q...For business service workflow,QoS-based services selection can't guarantee whether the composite service satisfies user' s requirement after delivery,because once any service interrupts or quality of service(QoS) maliciously reduces,the quality of workflow will be reduced.Trustworthy services can provide reliable QoS,so trustworthiness research could improve the efficiency of services selection.This paper investigates trust assessment in the perspective of workflow.Firstly,trust network of business service workflow(TN-BSW) is proposed to analyze trust attributes;then,the trust measurement system of TN-BSW is investigated to assess the trust value quantitatively;and then,a trust-aware service recommendation model(TaSRM) is proposed to enhance the efficiency of QoS-basedservices selection;finally,experiment shows the feasibility of TN-BSWand the performance of TaSRM.展开更多
Workflow logs that record the execution of business processes offer very valuable data resource for real-time enterprise performance measurement. In this paper, a novel scheme that uses the technology of data warehous...Workflow logs that record the execution of business processes offer very valuable data resource for real-time enterprise performance measurement. In this paper, a novel scheme that uses the technology of data warehouse and OLAP to explore workflow logs and create complex analysis reports for enterprise performance measurement is proposed. Three key points of this scheme are studied: 1) the measure set; 2) the open and flexible architecture for workflow logs analysis system; 3) the data models in WFMS and data warehouse. A case study that shows the validity of the scheme is also provided.展开更多
Forging die design is heavily dependent on engineers’experiences.But traditional AI technologies can barely pro-vide a standard knowledge representation style for knowledge transferring.This paper introduces ontology...Forging die design is heavily dependent on engineers’experiences.But traditional AI technologies can barely pro-vide a standard knowledge representation style for knowledge transferring.This paper introduces ontology into forging die design.3-layer forging die design ontology is built,which includes Meta-ontology,Domain-ontology and Bottom ontology.Further,by conceptualization,the concepts and their relations are formally addressed by primitives such as Term,Relation and Function etc,which are explicitly expressed by concept tree.Bottom ontology uses Knowledge Item and Prototype to represent and capture general knowledge for knowledge reuse and share.Forging die design ontology building approach is discussed for standard knowledge repre-sentation,knowledge mine and knowledge driven CAD design etc.And OWL language is employed for integration among different domain ontologies integration.Finally a locomotive forging die KBE system is presented to demonstrate this approach.展开更多
文摘以Si C-MOSFET和Si-IGBT器件混合型三电平有源中点钳位3L-ANPC(three-level active neutral point clamped)变流器拓扑为研究对象,对3种脉宽调制方式下的共模电磁干扰CM EMI(common-mode electromagnetic interference)特性进行研究。首先介绍了3L-ANPC变流器拓扑结构中Si C-MOSFET和Si-IGBT器件的2种组合模式及3种调制方式,然后对3L-ANPC变流器拓扑共模噪声传输机理进行分析,基于分析建立了包含寄生参数和噪声源的EMI模型,并推导出每种调制方式下传导路径的阻抗表达式,得到了共模传导路径阻抗特性曲线。最终通过实验验证了3种调制方式下器件混合型3L-ANPC变流器拓扑共模噪声的分析结论。
基金Supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20120002110034)Initiative Scientific Research Program of Tsinghua University(No.20111080998)
文摘For business service workflow,QoS-based services selection can't guarantee whether the composite service satisfies user' s requirement after delivery,because once any service interrupts or quality of service(QoS) maliciously reduces,the quality of workflow will be reduced.Trustworthy services can provide reliable QoS,so trustworthiness research could improve the efficiency of services selection.This paper investigates trust assessment in the perspective of workflow.Firstly,trust network of business service workflow(TN-BSW) is proposed to analyze trust attributes;then,the trust measurement system of TN-BSW is investigated to assess the trust value quantitatively;and then,a trust-aware service recommendation model(TaSRM) is proposed to enhance the efficiency of QoS-basedservices selection;finally,experiment shows the feasibility of TN-BSWand the performance of TaSRM.
文摘Workflow logs that record the execution of business processes offer very valuable data resource for real-time enterprise performance measurement. In this paper, a novel scheme that uses the technology of data warehouse and OLAP to explore workflow logs and create complex analysis reports for enterprise performance measurement is proposed. Three key points of this scheme are studied: 1) the measure set; 2) the open and flexible architecture for workflow logs analysis system; 3) the data models in WFMS and data warehouse. A case study that shows the validity of the scheme is also provided.
文摘Forging die design is heavily dependent on engineers’experiences.But traditional AI technologies can barely pro-vide a standard knowledge representation style for knowledge transferring.This paper introduces ontology into forging die design.3-layer forging die design ontology is built,which includes Meta-ontology,Domain-ontology and Bottom ontology.Further,by conceptualization,the concepts and their relations are formally addressed by primitives such as Term,Relation and Function etc,which are explicitly expressed by concept tree.Bottom ontology uses Knowledge Item and Prototype to represent and capture general knowledge for knowledge reuse and share.Forging die design ontology building approach is discussed for standard knowledge repre-sentation,knowledge mine and knowledge driven CAD design etc.And OWL language is employed for integration among different domain ontologies integration.Finally a locomotive forging die KBE system is presented to demonstrate this approach.
