A special form of the Stewart platform is presented in which the top platform and base platform are similar and corresponding vertices are connected by six prismatic joints.A closed-from solution for the forward displ...A special form of the Stewart platform is presented in which the top platform and base platform are similar and corresponding vertices are connected by six prismatic joints.A closed-from solution for the forward displacement analysis of this mechanism is developed.When the six vertices of the top platform are in a quadratic curve,this mechanism becomes singular.This new theoretical result is confirmed with a numerical example.展开更多
AIM： To analyze the hemodynamic and respiratory effects of propofol on patients undergoing gastroscopy and colonoscopy. METHODS： In this prospective study, conducted over a period of three years, 1,104 patients refe...AIM： To analyze the hemodynamic and respiratory effects of propofol on patients undergoing gastroscopy and colonoscopy. METHODS： In this prospective study, conducted over a period of three years, 1,104 patients referred for a same day GI endoscopy procedure were analyzed. All patients were given a propofol bolus （0.5-1.5 mg/kg）. Arterial blood pressure （BP） was monitored at 3 rain intervals and heart rate and oxygen saturation （SpO2） were recorded continuously by pulse oximetry. Analyzed data acquisition was carried out before, during, and after the procedure. RESULTS： A statistically significant reduction in mean arterial pressure was demonstrated （P〈0.001） when compared to pre-intervention values, but severe hypotension, defined as a systolic blood pressure below 60mmHg, was noted in only 5 patients （0.5%）. Oxygen saturation decreased from 96.5% to 94.4 % （P〈0.001）. A critical decrease in oxygen saturation （〈90%） was documented in 27 patients （2.4%）. CONCLUSION： Our results showed that propofol provided good sedation with excellent pain control, a short recovery time and no significant hemodynamic side effelts if carefully titrated. All the patients （and especially ASA Ⅲ group） require monitoring and care of an anesthesiologist.展开更多
Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety ...Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years （48 males, mean age 68.9 ± 3.0 years old） and 221 patients were〈65 years old （130 males, mean age 52.5 ± 10.4 years old）. After a mean follow-up period of 34.0 ± 15.1 months, 55 （57.9%） patients in the elderly group were free from ar-rhythmia recurrence compared with 149 （67.4%） patients in the younger group （P=0.169）. Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter （P=0.003）, hypertension （P=0.001）, dyslipidemia （P=0.039）, and coronary artery disease （P=0.018） were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.展开更多
Based on the Jacobian matrices relating the input speeds with the output speeds of linkages, a general method, which is used for solving the singularities of planar multi-loop multi-DOF linkages, is presented. The fou...Based on the Jacobian matrices relating the input speeds with the output speeds of linkages, a general method, which is used for solving the singularities of planar multi-loop multi-DOF linkages, is presented. The four kinds of singularities of 2-DOF planar seven-bar linkages used in hybrid actuators are analyzed in detail by this method. Its five kinds of singular positions whose characteristics are discussed respectively are discovered. Three approaches are proposed on how to avoid the singular positions of planar multi-loop multi-DOF linkages. Based on the assemblability of planar single-loop N-bar chains or linkages, the geometry conditions are investigated and discovered to avoid the singular positions of the linkages. In order to versify aforementioned conclusions, a case is given in which the singular curves are plotted and simulated.展开更多
A simple method,based on harmonic wavelet analysis is proposed for the decomposition of a given energy bounded signal into a periodic signal and a pulse.Alike a denoising method,the first part signal it might represen...A simple method,based on harmonic wavelet analysis is proposed for the decomposition of a given energy bounded signal into a periodic signal and a pulse.Alike a denoising method,the first part signal it might represent a smooth periodic function while the pulse is a singular unpredicted perturbation (taken as a fault).It will be shown that,under some general conditions,by a simple projection into two disjoint space of functions we can easily separate the periodic component of the signal from the fault (represented by the singular pulse).展开更多
In this paper, the dynamic effect of oceanic upwelling on the intensity of E1 Nifio-Southern Oscilla tion （ENSO） is studied using a simple coupled model （Zebiak-Cane Model）. The term balance analysis in the temper...In this paper, the dynamic effect of oceanic upwelling on the intensity of E1 Nifio-Southern Oscilla tion （ENSO） is studied using a simple coupled model （Zebiak-Cane Model）. The term balance analysis in the temperature variability equation shows that the anomalous upwelling of the mean vertical temperature gradient and the mean advection of the anomalous meridional tem perature gradient are the two of most important factors that determine the intensity of ENSO events, in which the ＂vertical oceanic heat flux＂ in the eastern equatorial Pa cific （EEP） is the primary influencing factor. The lag cor relation between ＂vertical heat flux （VHF）＂ and ENSO intensity shows that the highest correlation occurs when the former leads the latter by one to two weeks. The VHF is positively correlated with the background thermocline strength in the EEP, and an increase of both could result in strong ENSO variability. Comparison of the forced and coupled experiments suggests that the coupled process can affect both the intensity and freauencv of ENSO.展开更多
Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In ...Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In network-based control systems,error codes induced by noisy channel can significantly decrease the quality of control.To solve this problem,the network-based control system with delay and noisy channel is firstly modeled as an asynchronous dynamic system(ADS).Secondly,conditions of packet with error codes(PEC)loss rate by using M-ary modulation are obtained based on dynamic output feedback scheme.Thirdly,more importantly,the selection principle of M-ary modulation is proposed according to the measured signal-to-noise ratio(SNR)and conditions of PEC loss rate.Finally,system stability is analyzed and controller is designed through Lyapunov function and linear matrix inequality(LMI)scheme,and numerical simulations are made to demonstrate the effectiveness of the proposed scheme.展开更多
By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rup...By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rupture planes of strong events of MS7.8,MS7.1 and MS6.9 in the sequence.It indicates that the complex pattern is closely related to the earthquake source,and the NE-,NWW-and NW-trending regional fault zones,which have been revealed by the research of the pre-seismicity anomaly.In summary,the source is located in the junction of the three fault zones,and the rupture planes of the three strong events located in the source can be regarded as the locked segments on the three fault zones.On these grounds,the paper explains the complexity of the source and epicentral distribution of aftershocks.展开更多
China is a world＇s ancient civilization with a long history of five thousand years; meanwhile, it is also the headstream of sports culture. Chinese sports aim at building the body and self-cultivation. The movement s...China is a world＇s ancient civilization with a long history of five thousand years; meanwhile, it is also the headstream of sports culture. Chinese sports aim at building the body and self-cultivation. The movement structures of sports are mainly the simulation of all kinds of movement of animals, which are particular about static and dynamic equilibrium, firmness, and gentleness, getting refined internally and externally. The feature of Chinese sports is the unification of form and spirit. The pattern of Chinese sports is closely related with Chinese philosophy thought, and the constructed Chinese sports culture has become the essential part of Chinese traditional philosophy. Chinese sports have integrated fitness and aesthetic appreciation into one, which is the specific expression of Chinese traditional thought. However, western sports have integrated with western philosophy thought with strong athletic tint. The characteristic of western sports has a necessary connection with the ancient Greek thought. Ancient Greeks had realized that the relationship between human and the nature was not totally dependent with contrariety, so they thought only fighting with the nature could they survive. The origins of thought of Chinese and western sports cultures decide the differences between Chinese and western sports. The harmony of China and competition of the west can be both embodied in sports. This thesis will analyze the differences between Chinese and western sports philosophy.展开更多
In this paper, post-fault-tolerant control strategies for quad-inverter multiphase-multilevel induction motor drives are investigated. More specifically, four standard two-level three-phase VSIs （voltage source inver...In this paper, post-fault-tolerant control strategies for quad-inverter multiphase-multilevel induction motor drives are investigated. More specifically, four standard two-level three-phase VSIs （voltage source inverters） supplying the open-end windings of a dual three-phase induction motor is considered, quadrupling the power capability of a single VSI with given voltage and current ratings. In healthy conditions, the control algorithm is able to generate multi-level voltage waveforms, equivalent to the ones of a three-level inverter and to share the total motor power among the four dc sources in each switching period. This sharing capability is investigated under post-fault operating conditions, when one VSI must be completely insulated due to a severe failure on it. In this case, the conversion power unit can operate with a reduced power rating by a proper modulation of the remaining three VSIs. The whole ac motor drive has been numerically implemented, and the effectiveness of the proposed control strategies under healthy and post-fault operating conditions have been proved.展开更多
This paper presents two aggregation strategies in convex intersection region for the distributed mobile sensor network(MSN) with heterogeneous dynamics. First, the authors analyze individual local perception model and...This paper presents two aggregation strategies in convex intersection region for the distributed mobile sensor network(MSN) with heterogeneous dynamics. First, the authors analyze individual local perception model and dynamics model, set the intersection of all the local perceptions as the region of interest(ROI). The MSN consists of sensors with first-order dynamics and second-order dynamics. Then, the authors design a control strategy to ensure that individuals aggregate at a point in the ROI relying on their local perceptions and the locations of neighbors within their communication scope. The authors describe this situation of aggregation as rendezvous. In addition, the authors introduce artificial potential field to make sensors deploy dispersedly in a bounded range near the ROI,which the authors call dispersed deployment. Finally, the authors prove the stability of the proposed strategies and validate the theoretical results by simulations. This research is applied for the cooperative deployment and data collection of mobile platforms with different dynamics under the condition of inaccurate perception.展开更多
文摘A special form of the Stewart platform is presented in which the top platform and base platform are similar and corresponding vertices are connected by six prismatic joints.A closed-from solution for the forward displacement analysis of this mechanism is developed.When the six vertices of the top platform are in a quadratic curve,this mechanism becomes singular.This new theoretical result is confirmed with a numerical example.
基金Supported by "Bates" Clinic, Svetice 15, Zagreb, Croatia, in the form of grant, equipment and drugs
文摘AIM： To analyze the hemodynamic and respiratory effects of propofol on patients undergoing gastroscopy and colonoscopy. METHODS： In this prospective study, conducted over a period of three years, 1,104 patients referred for a same day GI endoscopy procedure were analyzed. All patients were given a propofol bolus （0.5-1.5 mg/kg）. Arterial blood pressure （BP） was monitored at 3 rain intervals and heart rate and oxygen saturation （SpO2） were recorded continuously by pulse oximetry. Analyzed data acquisition was carried out before, during, and after the procedure. RESULTS： A statistically significant reduction in mean arterial pressure was demonstrated （P〈0.001） when compared to pre-intervention values, but severe hypotension, defined as a systolic blood pressure below 60mmHg, was noted in only 5 patients （0.5%）. Oxygen saturation decreased from 96.5% to 94.4 % （P〈0.001）. A critical decrease in oxygen saturation （〈90%） was documented in 27 patients （2.4%）. CONCLUSION： Our results showed that propofol provided good sedation with excellent pain control, a short recovery time and no significant hemodynamic side effelts if carefully titrated. All the patients （and especially ASA Ⅲ group） require monitoring and care of an anesthesiologist.
文摘Background Atrial fibrillation （AF） catheter ablation has emerged as a promising treatment strategy for AF, but has not been widely adopted in the elderly population. The present study aimed to determine the safety and efficacy of AF catheter ablation in the elderly popula-tion. Methods and Results The study population consisted of 316 patients with paroxysmal AF who underwent left atrial ablation. Ninety-five patients were≥65 years （48 males, mean age 68.9 ± 3.0 years old） and 221 patients were〈65 years old （130 males, mean age 52.5 ± 10.4 years old）. After a mean follow-up period of 34.0 ± 15.1 months, 55 （57.9%） patients in the elderly group were free from ar-rhythmia recurrence compared with 149 （67.4%） patients in the younger group （P=0.169）. Procedural complications were uncommon in both study groups. In logistic regression analysis, left atrial diameter （P=0.003）, hypertension （P=0.001）, dyslipidemia （P=0.039）, and coronary artery disease （P=0.018） were independent predictors of AF recurrence in the elderly population. Conclusions Catheter ablation of AF is safe and effective in older patients. Invasive strategies should be considered as an alternative choice in symptomatic elderly patients with AF.
文摘Based on the Jacobian matrices relating the input speeds with the output speeds of linkages, a general method, which is used for solving the singularities of planar multi-loop multi-DOF linkages, is presented. The four kinds of singularities of 2-DOF planar seven-bar linkages used in hybrid actuators are analyzed in detail by this method. Its five kinds of singular positions whose characteristics are discussed respectively are discovered. Three approaches are proposed on how to avoid the singular positions of planar multi-loop multi-DOF linkages. Based on the assemblability of planar single-loop N-bar chains or linkages, the geometry conditions are investigated and discovered to avoid the singular positions of the linkages. In order to versify aforementioned conclusions, a case is given in which the singular curves are plotted and simulated.
文摘A simple method,based on harmonic wavelet analysis is proposed for the decomposition of a given energy bounded signal into a periodic signal and a pulse.Alike a denoising method,the first part signal it might represent a smooth periodic function while the pulse is a singular unpredicted perturbation (taken as a fault).It will be shown that,under some general conditions,by a simple projection into two disjoint space of functions we can easily separate the periodic component of the signal from the fault (represented by the singular pulse).
基金supported by the National Natural Science Foundation of China (Grant Nos. 40976007 and 41176002)the Special Fund for Meteorological Scientific Research in the Public Interest of China Meteorological Administration (Grant No. GYHY201006022)the Norwegian Research Council through the East Asian DecCen Project (Grant No. 193690/S30)
文摘In this paper, the dynamic effect of oceanic upwelling on the intensity of E1 Nifio-Southern Oscilla tion （ENSO） is studied using a simple coupled model （Zebiak-Cane Model）. The term balance analysis in the temperature variability equation shows that the anomalous upwelling of the mean vertical temperature gradient and the mean advection of the anomalous meridional tem perature gradient are the two of most important factors that determine the intensity of ENSO events, in which the ＂vertical oceanic heat flux＂ in the eastern equatorial Pa cific （EEP） is the primary influencing factor. The lag cor relation between ＂vertical heat flux （VHF）＂ and ENSO intensity shows that the highest correlation occurs when the former leads the latter by one to two weeks. The VHF is positively correlated with the background thermocline strength in the EEP, and an increase of both could result in strong ENSO variability. Comparison of the forced and coupled experiments suggests that the coupled process can affect both the intensity and freauencv of ENSO.
基金Project(61172022) supported by the National Natural Science Foundation of ChinaProject(GDW20151100010) supported by the State Administration of Foreign Experts Affairs of China
文摘Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In network-based control systems,error codes induced by noisy channel can significantly decrease the quality of control.To solve this problem,the network-based control system with delay and noisy channel is firstly modeled as an asynchronous dynamic system(ADS).Secondly,conditions of packet with error codes(PEC)loss rate by using M-ary modulation are obtained based on dynamic output feedback scheme.Thirdly,more importantly,the selection principle of M-ary modulation is proposed according to the measured signal-to-noise ratio(SNR)and conditions of PEC loss rate.Finally,system stability is analyzed and controller is designed through Lyapunov function and linear matrix inequality(LMI)scheme,and numerical simulations are made to demonstrate the effectiveness of the proposed scheme.
基金funded by the fundamental research funds of Institute of Earthquake Science,China Earthquake Administration (690206)
文摘By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rupture planes of strong events of MS7.8,MS7.1 and MS6.9 in the sequence.It indicates that the complex pattern is closely related to the earthquake source,and the NE-,NWW-and NW-trending regional fault zones,which have been revealed by the research of the pre-seismicity anomaly.In summary,the source is located in the junction of the three fault zones,and the rupture planes of the three strong events located in the source can be regarded as the locked segments on the three fault zones.On these grounds,the paper explains the complexity of the source and epicentral distribution of aftershocks.
文摘China is a world＇s ancient civilization with a long history of five thousand years; meanwhile, it is also the headstream of sports culture. Chinese sports aim at building the body and self-cultivation. The movement structures of sports are mainly the simulation of all kinds of movement of animals, which are particular about static and dynamic equilibrium, firmness, and gentleness, getting refined internally and externally. The feature of Chinese sports is the unification of form and spirit. The pattern of Chinese sports is closely related with Chinese philosophy thought, and the constructed Chinese sports culture has become the essential part of Chinese traditional philosophy. Chinese sports have integrated fitness and aesthetic appreciation into one, which is the specific expression of Chinese traditional thought. However, western sports have integrated with western philosophy thought with strong athletic tint. The characteristic of western sports has a necessary connection with the ancient Greek thought. Ancient Greeks had realized that the relationship between human and the nature was not totally dependent with contrariety, so they thought only fighting with the nature could they survive. The origins of thought of Chinese and western sports cultures decide the differences between Chinese and western sports. The harmony of China and competition of the west can be both embodied in sports. This thesis will analyze the differences between Chinese and western sports philosophy.
文摘In this paper, post-fault-tolerant control strategies for quad-inverter multiphase-multilevel induction motor drives are investigated. More specifically, four standard two-level three-phase VSIs （voltage source inverters） supplying the open-end windings of a dual three-phase induction motor is considered, quadrupling the power capability of a single VSI with given voltage and current ratings. In healthy conditions, the control algorithm is able to generate multi-level voltage waveforms, equivalent to the ones of a three-level inverter and to share the total motor power among the four dc sources in each switching period. This sharing capability is investigated under post-fault operating conditions, when one VSI must be completely insulated due to a severe failure on it. In this case, the conversion power unit can operate with a reduced power rating by a proper modulation of the remaining three VSIs. The whole ac motor drive has been numerically implemented, and the effectiveness of the proposed control strategies under healthy and post-fault operating conditions have been proved.
基金supported by the National Natural Science Foundation of China under Grant No.61203078the Foundation for Innovative Research Groups of the National Natural Science Foundation of China under Grant No.61321002+3 种基金the Projects of Major International(Regional)Joint Research Program NSFC under Grant No.61120106010the Beijing Education Committee Cooperation Building Foundation Projectthe Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT1208the Chang Jiang Scholars Program,and the Beijing Outstanding Ph.D.Program Mentor under Grant No.20131000704
文摘This paper presents two aggregation strategies in convex intersection region for the distributed mobile sensor network(MSN) with heterogeneous dynamics. First, the authors analyze individual local perception model and dynamics model, set the intersection of all the local perceptions as the region of interest(ROI). The MSN consists of sensors with first-order dynamics and second-order dynamics. Then, the authors design a control strategy to ensure that individuals aggregate at a point in the ROI relying on their local perceptions and the locations of neighbors within their communication scope. The authors describe this situation of aggregation as rendezvous. In addition, the authors introduce artificial potential field to make sensors deploy dispersedly in a bounded range near the ROI,which the authors call dispersed deployment. Finally, the authors prove the stability of the proposed strategies and validate the theoretical results by simulations. This research is applied for the cooperative deployment and data collection of mobile platforms with different dynamics under the condition of inaccurate perception.
