To improve the accuracy of the stator winding fault diagnosis in induction motor,a new diagnostic method based on the Hilbert-Huang transform(HHT)was proposed.The ratio of fundamental zero sequence voltage to positive...To improve the accuracy of the stator winding fault diagnosis in induction motor,a new diagnostic method based on the Hilbert-Huang transform(HHT)was proposed.The ratio of fundamental zero sequence voltage to positive sequence voltage after switch-off was selected as the stator fault characteristic,which could effectively avoid the influence of the supply unbalance and the load fluctuation,and directly represent the asymmetry in the stator.Using the empirical mode decomposition(EMD)based on HHT,the zero sequence voltage after switch-off was decomposed and the fundamental component was extracted.Then,the fault characteristic can be acquired.Experimental results on a 4-kW induction motor demonstrate the feasibility and effectiveness of this method.展开更多
The present paper introduces the concepts of exergy and treats it applications to analysis of the gain in exergy efficiency between one-step and multi-step thermal processes. The analysis, which is carried out with th...The present paper introduces the concepts of exergy and treats it applications to analysis of the gain in exergy efficiency between one-step and multi-step thermal processes. The analysis, which is carried out with the Excel-based SEPE program, is exemplified with the comparison between single-step and two-steps heat pump setup for providing heat to a floor heating system and for domestic hot water. The paper discusses the use of the concept of exergy efficiency as a measure of success for design of a heat pump application and how the use of information on exergy destruction and temperature levels in different parts of the system add a new perspective to the analysis and the evaluation of the system performance. The paper shows how this information can be used to improve the system configuration and also the operation of the system for given boundary conditions. This is especially useful when the energy from the low temperature sources can be utilized at different temperature or quality levels such as for space heating and domestic hot water.展开更多
The formulation of recommendations is a crucial step in the development of clinical practice guidelines,which requires tools provided by the GRADE methodology.These tools include the evidence quality assessment tool,t...The formulation of recommendations is a crucial step in the development of clinical practice guidelines,which requires tools provided by the GRADE methodology.These tools include the evidence quality assessment tool,the evidence summary tool,and the evidence-to-decision(EtD)framework.Although there is a methodologically guided standard pathway for formulating recommendations in clinical practice guidelines,it remains unclear how to translate this theoretical pathway into the practical process for formulating recommendations and what the specific steps in this process entail.Therefore,this paper takes the World Federation of Acupuncture-Moxibustion Societies Clinical Practice Guidelines on Acupuncture and Moxibustion:Allergic Rhinitis as an example to detail the full process of formulating recommendations and summaries it into a three-step method.Step one:Collect original materials from different sources to create EtD table.Step two:Distribute and collect EtD table,and preliminarily gather the recommendation voting results.Step three:Organize"salami-slicing pattern"guideline development group consensus meeting to formulate recommendations.The three-step method for formulating recommendations in clinical practice guidelines fully utilizes the GRADE EtD table to provide guideline development group with decision-making foundation and reference from multiple dimensions,including the importance of clinical questions,balance of benefits and harms,quality of evidence,resource required,values and preferences,health equity,acceptability,and feasibility.This approach enhances the scientific and practical nature of guideline recommendations.This paper provides a standard operating procedure to formulate recommendations for the incoming clinical practice guidelines,which aims to establish a standard pathway for the formulation of acupuncture clinical practice guideline recommendations.展开更多
Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this...Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this study, the authors use the Mean Shift Outlier Model(MSOM) to detect outliers in HIV model based on the two-step estimation of ODE. Approximate formula for shift parameter is derived. Furthermore, a score test statistic is constructed and its approximating distribution is established. The simulation results show that: 1) The boundary points have more impact on the parameter estimation relative to interior points. 2) The proposed procedure can detect the outliers effectively. The authors illustrate the proposed approach using an application example from an HIV clinical trial and find similar pattern to the simulation studies.展开更多
基金Project (No. 50677060) supported by the National Natural ScienceFoundation of China
文摘To improve the accuracy of the stator winding fault diagnosis in induction motor,a new diagnostic method based on the Hilbert-Huang transform(HHT)was proposed.The ratio of fundamental zero sequence voltage to positive sequence voltage after switch-off was selected as the stator fault characteristic,which could effectively avoid the influence of the supply unbalance and the load fluctuation,and directly represent the asymmetry in the stator.Using the empirical mode decomposition(EMD)based on HHT,the zero sequence voltage after switch-off was decomposed and the fundamental component was extracted.Then,the fault characteristic can be acquired.Experimental results on a 4-kW induction motor demonstrate the feasibility and effectiveness of this method.
文摘The present paper introduces the concepts of exergy and treats it applications to analysis of the gain in exergy efficiency between one-step and multi-step thermal processes. The analysis, which is carried out with the Excel-based SEPE program, is exemplified with the comparison between single-step and two-steps heat pump setup for providing heat to a floor heating system and for domestic hot water. The paper discusses the use of the concept of exergy efficiency as a measure of success for design of a heat pump application and how the use of information on exergy destruction and temperature levels in different parts of the system add a new perspective to the analysis and the evaluation of the system performance. The paper shows how this information can be used to improve the system configuration and also the operation of the system for given boundary conditions. This is especially useful when the energy from the low temperature sources can be utilized at different temperature or quality levels such as for space heating and domestic hot water.
基金Supported by the National Key Research and Development Program of China:2019YFC17122002019YFC1712203。
文摘The formulation of recommendations is a crucial step in the development of clinical practice guidelines,which requires tools provided by the GRADE methodology.These tools include the evidence quality assessment tool,the evidence summary tool,and the evidence-to-decision(EtD)framework.Although there is a methodologically guided standard pathway for formulating recommendations in clinical practice guidelines,it remains unclear how to translate this theoretical pathway into the practical process for formulating recommendations and what the specific steps in this process entail.Therefore,this paper takes the World Federation of Acupuncture-Moxibustion Societies Clinical Practice Guidelines on Acupuncture and Moxibustion:Allergic Rhinitis as an example to detail the full process of formulating recommendations and summaries it into a three-step method.Step one:Collect original materials from different sources to create EtD table.Step two:Distribute and collect EtD table,and preliminarily gather the recommendation voting results.Step three:Organize"salami-slicing pattern"guideline development group consensus meeting to formulate recommendations.The three-step method for formulating recommendations in clinical practice guidelines fully utilizes the GRADE EtD table to provide guideline development group with decision-making foundation and reference from multiple dimensions,including the importance of clinical questions,balance of benefits and harms,quality of evidence,resource required,values and preferences,health equity,acceptability,and feasibility.This approach enhances the scientific and practical nature of guideline recommendations.This paper provides a standard operating procedure to formulate recommendations for the incoming clinical practice guidelines,which aims to establish a standard pathway for the formulation of acupuncture clinical practice guideline recommendations.
基金supported by the Fundamental Research Funds for the Cental Universities under Grant No.JB140706the National Funds of China for Young Scientists under Grant Nos.11302157 and 11301409
文摘Ordinary differential equation(ODE) are widely used for quantifying HIV viral dynamics.It is interesting but challenging to estimate ODE parameters from noisy data, especially when the data have some outliers. In this study, the authors use the Mean Shift Outlier Model(MSOM) to detect outliers in HIV model based on the two-step estimation of ODE. Approximate formula for shift parameter is derived. Furthermore, a score test statistic is constructed and its approximating distribution is established. The simulation results show that: 1) The boundary points have more impact on the parameter estimation relative to interior points. 2) The proposed procedure can detect the outliers effectively. The authors illustrate the proposed approach using an application example from an HIV clinical trial and find similar pattern to the simulation studies.
