The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm....The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.展开更多
The problem of linear time-varying（LTV） system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system mo...The problem of linear time-varying（LTV） system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the ＂frozen-time＂ assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system＇s stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes.展开更多
In telerobotic system for remote welding, human-machine interface is one of the most important factor for enhancing capability and efficiency. This paper presents an architecture design of human-machine interface for ...In telerobotic system for remote welding, human-machine interface is one of the most important factor for enhancing capability and efficiency. This paper presents an architecture design of human-machine interface for welding telerobotic system： welding multi-modal human-machine interface. The human-machine interface integrated several control modes, which are namely shared control, teleteaching, supervisory control and local autonomous control. Space mouse, panoramic vision camera and graphics simulation system are also integrated into the human-machine interface for welding teleoperation. Finally, weld seam tracing and welding experiments of U-shape seam are performed by these control modes respectively. The results show that the system has better performance of human-machine interaction and complexity environment welding.展开更多
Based on the interpersonal function in Halliday’s systemic functional grammar,"Miranda Warnings",the typical English Police Caution,is analyzed from the aspects of Mood system,Modality system and Appraisal ...Based on the interpersonal function in Halliday’s systemic functional grammar,"Miranda Warnings",the typical English Police Caution,is analyzed from the aspects of Mood system,Modality system and Appraisal system,with the aim of exploring its interpersonal meanings.Results show that:first,the declarative mood and interrogative mood used in the police caution protect the legitimate rights of the interrogated;second,the widely use of Low value modal verbs demonstrates a more humane and democratic legislation principle;and third,the absence of Affect resources and the frequent application of Capacity resources narrow the interpersonal distance between policeman and the interrogated,reflecting the transformation in policeman’s interrogation practices.展开更多
Modality is used to express subjective judgment as well as the speaker’s opinions and attitudes.This paper aims to analyze the reporters’orientation reflected by linguistic modal expressions in English news reports ...Modality is used to express subjective judgment as well as the speaker’s opinions and attitudes.This paper aims to analyze the reporters’orientation reflected by linguistic modal expressions in English news reports from the perspective of Systemic-Functional Grammar,especially from the perspective of type,value,orientation and polarity.展开更多
文章基于地铁集团实际业务场景,设计了基于多模式出行的城际客票一体化系统。以MaaS(Mobility as a Service)理念为核心,构建软硬件协同架构,通过数据采集与传输、路径融合计算、用户界面交互及智能推荐算法实现路径动态优化机制,并以...文章基于地铁集团实际业务场景,设计了基于多模式出行的城际客票一体化系统。以MaaS(Mobility as a Service)理念为核心,构建软硬件协同架构,通过数据采集与传输、路径融合计算、用户界面交互及智能推荐算法实现路径动态优化机制,并以典型城际走廊为实验场景进行了模拟验证。实验结果表明,系统在响应速度、推荐准确性与用户满意度等方面均表现优越,具备良好的工程落地能力。展开更多
A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Usin...A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Using Gabor expansion and synthesis theory, measuredresponses are represented in the time-frequency domain and modal components are reconstructed bytime-frequency filtering. The Hilbert transform is applied to obtain time histories of the amplitudeand phase angle of each modal component, from which time-varying frequencies and damping ratios areidentified. The proposed method has been demonstrated with a numerical example in which a lineartime-varying system of two degrees of freedom is used to validate the identification scheme based ontime-frequency representation. Simulation results have indicated that time-frequency representationpresents an effective tool for modal parameter identification of time-varying systems.展开更多
Steel jacket-type platforms are the common kind of the offshore structures and health monitoring is an important issue in their safety assessment. In the present study, a new damage detection method is adopted for thi...Steel jacket-type platforms are the common kind of the offshore structures and health monitoring is an important issue in their safety assessment. In the present study, a new damage detection method is adopted for this kind of structures and inspected experimentally by use of a laboratory model. The method is investigated for developing the robust damage detection technique which is less sensitive to both measurement and analytical model uncertainties. For this purpose, incorporation of the artificial immune system with weighted attributes （AISWA） method into finite element （FE） model updating is proposed and compared with other methods for exploring its effectiveness in damage identification. Based on mimicking immune recognition, noise simulation and attributes weighting, the method offers important advantages and has high success rates. Therefore, it is proposed as a suitable method for the detection of the failures in the large civil engineering structures with complicated structural geometry, such as the considered case study.展开更多
Stochastic Subspace Identification (SSI) is a novel time domain identification method, which directly uses operational response data to identify the system model by linear algebraic manipulations such as QR facto...Stochastic Subspace Identification (SSI) is a novel time domain identification method, which directly uses operational response data to identify the system model by linear algebraic manipulations such as QR factorization and Singular Value Decomposition (SVD). This paper deals with SSI and its applications for structural modal identification. The NASA mini mast model is used for simulations to illustrate how to select input parameters, and to demonstrate identification precision. A real building structure, the Heritage Court Tower (HCT) in Canada is analyzed. From the simulation and test researches, the conclusions can be made to instruct how to identify structural modal parameters using SSI method.展开更多
Assessing the prognosis before treatment for metastatic spine tumor is extremely important in therapy selection.Therefore,we review some prognostic scoring systems and their outcomes.Articles with combinations of two ...Assessing the prognosis before treatment for metastatic spine tumor is extremely important in therapy selection.Therefore,we review some prognostic scoring systems and their outcomes.Articles with combinations of two keywords among"metastatic spine tumor"and"prognosis","score","scoring system","predicting",or"life expectancy"were searched for in Pub Med.As a result,236 articles were extracted.Those referring to representative scoring systems about predicting the survival of patients with metastatic spine tumors were used.The significance and limits of these scoring systems,and the future perspectives were described.Tokuhashi score,Tomita score,Baur score,Linden score,Rades score,and Katagiri score were introduced.They are all scoring systems prepared by combining factors that affect prognosis.The primary site of cancer and visceral metastasis were common factors in all of these scoring systems.Other factors selected to influence the prognosis varied.They were useful to roughly predict thesurvival period,such as,"more than one year or not"or"more than six months or not".In particular,they were utilized for decision-making about operative indications and avoidance of excessive medical treatment.Because the function depended on the survival period in the patients with metastatic spine tumor,it was also utilized in assessing functional prognosis.However,no scoring system had more than 90%consistency between the predicted and actual survival periods.Future perspectives should adopt more oncological viewpoints with adjustment of the process of treatment for metastatic spine tumor.展开更多
Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural...Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural frequencies of soil deposit, nor simulate a damping of frequency independence. This research develops a new discrete model for onedimensional viscoelastic response analysis of layered soil deposit based on the mode equivalence method. The new discrete model is a one-dimensional equivalent multi-degree-of-freedom（MDOF） system characterized by a series of concentrated masses, springs and dashpots with a special configuration. The dynamic response of the equivalent MDOF system is analytically derived and the physical parameters are formulated in terms of modal properties. The equivalent MDOF system is verified through a comparison of amplification functions with the available theoretical solutions. The appropriate number of degrees of freedom（DOFs） in the equivalent MDOF system is estimated. A comparative study of the equivalent MDOF system with the existing discrete models is performed. It is shown that the proposed equivalent MDOF system can exactly present the natural frequencies and the hysteretic damping of soil deposits and provide more accurate results with fewer DOFs.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.10672092 and 10725209)Scientific Research Project of Shanghai Municipal Education Commission(No.07ZZ07)Shanghai Leading Academic Discipline Project(No.Y0103)
文摘The modal method is applied to analyze coupled vibration of belt drive systems. A belt drive system is a hybrid system consisting of continuous belts modeled as strings as well as discrete pulleys and a tensioner arm. The characteristic equation of the system is derived from the governing equation. Numerical results demenstrate the effects of the transport speed and the initial tension on natural frequencies.
基金Supported by the China Scholarship Council,National Natural Science Foundation of China(Grant No.11402022)the Interuniversity Attraction Poles Programme of the Belgian Science Policy Office(DYSCO)+1 种基金the Fund for Scientific Research–Flanders(FWO)the Research Fund KU Leuven
文摘The problem of linear time-varying（LTV） system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the ＂frozen-time＂ assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system＇s stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes.
文摘In telerobotic system for remote welding, human-machine interface is one of the most important factor for enhancing capability and efficiency. This paper presents an architecture design of human-machine interface for welding telerobotic system： welding multi-modal human-machine interface. The human-machine interface integrated several control modes, which are namely shared control, teleteaching, supervisory control and local autonomous control. Space mouse, panoramic vision camera and graphics simulation system are also integrated into the human-machine interface for welding teleoperation. Finally, weld seam tracing and welding experiments of U-shape seam are performed by these control modes respectively. The results show that the system has better performance of human-machine interaction and complexity environment welding.
文摘Based on the interpersonal function in Halliday’s systemic functional grammar,"Miranda Warnings",the typical English Police Caution,is analyzed from the aspects of Mood system,Modality system and Appraisal system,with the aim of exploring its interpersonal meanings.Results show that:first,the declarative mood and interrogative mood used in the police caution protect the legitimate rights of the interrogated;second,the widely use of Low value modal verbs demonstrates a more humane and democratic legislation principle;and third,the absence of Affect resources and the frequent application of Capacity resources narrow the interpersonal distance between policeman and the interrogated,reflecting the transformation in policeman’s interrogation practices.
文摘Modality is used to express subjective judgment as well as the speaker’s opinions and attitudes.This paper aims to analyze the reporters’orientation reflected by linguistic modal expressions in English news reports from the perspective of Systemic-Functional Grammar,especially from the perspective of type,value,orientation and polarity.
文摘文章基于地铁集团实际业务场景,设计了基于多模式出行的城际客票一体化系统。以MaaS(Mobility as a Service)理念为核心,构建软硬件协同架构,通过数据采集与传输、路径融合计算、用户界面交互及智能推荐算法实现路径动态优化机制,并以典型城际走廊为实验场景进行了模拟验证。实验结果表明,系统在响应速度、推荐准确性与用户满意度等方面均表现优越,具备良好的工程落地能力。
基金Automobile Industrial Science Foundation of Shanghai (No.2000187)
文摘A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Using Gabor expansion and synthesis theory, measuredresponses are represented in the time-frequency domain and modal components are reconstructed bytime-frequency filtering. The Hilbert transform is applied to obtain time histories of the amplitudeand phase angle of each modal component, from which time-varying frequencies and damping ratios areidentified. The proposed method has been demonstrated with a numerical example in which a lineartime-varying system of two degrees of freedom is used to validate the identification scheme based ontime-frequency representation. Simulation results have indicated that time-frequency representationpresents an effective tool for modal parameter identification of time-varying systems.
文摘Steel jacket-type platforms are the common kind of the offshore structures and health monitoring is an important issue in their safety assessment. In the present study, a new damage detection method is adopted for this kind of structures and inspected experimentally by use of a laboratory model. The method is investigated for developing the robust damage detection technique which is less sensitive to both measurement and analytical model uncertainties. For this purpose, incorporation of the artificial immune system with weighted attributes （AISWA） method into finite element （FE） model updating is proposed and compared with other methods for exploring its effectiveness in damage identification. Based on mimicking immune recognition, noise simulation and attributes weighting, the method offers important advantages and has high success rates. Therefore, it is proposed as a suitable method for the detection of the failures in the large civil engineering structures with complicated structural geometry, such as the considered case study.
文摘Stochastic Subspace Identification (SSI) is a novel time domain identification method, which directly uses operational response data to identify the system model by linear algebraic manipulations such as QR factorization and Singular Value Decomposition (SVD). This paper deals with SSI and its applications for structural modal identification. The NASA mini mast model is used for simulations to illustrate how to select input parameters, and to demonstrate identification precision. A real building structure, the Heritage Court Tower (HCT) in Canada is analyzed. From the simulation and test researches, the conclusions can be made to instruct how to identify structural modal parameters using SSI method.
文摘Assessing the prognosis before treatment for metastatic spine tumor is extremely important in therapy selection.Therefore,we review some prognostic scoring systems and their outcomes.Articles with combinations of two keywords among"metastatic spine tumor"and"prognosis","score","scoring system","predicting",or"life expectancy"were searched for in Pub Med.As a result,236 articles were extracted.Those referring to representative scoring systems about predicting the survival of patients with metastatic spine tumors were used.The significance and limits of these scoring systems,and the future perspectives were described.Tokuhashi score,Tomita score,Baur score,Linden score,Rades score,and Katagiri score were introduced.They are all scoring systems prepared by combining factors that affect prognosis.The primary site of cancer and visceral metastasis were common factors in all of these scoring systems.Other factors selected to influence the prognosis varied.They were useful to roughly predict thesurvival period,such as,"more than one year or not"or"more than six months or not".In particular,they were utilized for decision-making about operative indications and avoidance of excessive medical treatment.Because the function depended on the survival period in the patients with metastatic spine tumor,it was also utilized in assessing functional prognosis.However,no scoring system had more than 90%consistency between the predicted and actual survival periods.Future perspectives should adopt more oncological viewpoints with adjustment of the process of treatment for metastatic spine tumor.
基金National Natural Science Foundation of China(51208296&51478343)Shanghai Committee of Science and Technology(13231200503)+2 种基金Fundamental Research Funds for the Central Universities(2013KJ095&101201438)Shanghai Educational Development Foundation(13CG17)National Key Technology R&D Program(2012BAK24B04)
文摘Discrete models such as the lumped parameter model and the finite element model are widely used in the solution of soil amplification of earthquakes. However, neither of the models will accurately estimate the natural frequencies of soil deposit, nor simulate a damping of frequency independence. This research develops a new discrete model for onedimensional viscoelastic response analysis of layered soil deposit based on the mode equivalence method. The new discrete model is a one-dimensional equivalent multi-degree-of-freedom（MDOF） system characterized by a series of concentrated masses, springs and dashpots with a special configuration. The dynamic response of the equivalent MDOF system is analytically derived and the physical parameters are formulated in terms of modal properties. The equivalent MDOF system is verified through a comparison of amplification functions with the available theoretical solutions. The appropriate number of degrees of freedom（DOFs） in the equivalent MDOF system is estimated. A comparative study of the equivalent MDOF system with the existing discrete models is performed. It is shown that the proposed equivalent MDOF system can exactly present the natural frequencies and the hysteretic damping of soil deposits and provide more accurate results with fewer DOFs.
