This paper deals with the synchronization of chaotic systems with structure or parameters difference. Nonlinear differential geometry theory was applied to transform the chaotic discrepancy system into canonical form....This paper deals with the synchronization of chaotic systems with structure or parameters difference. Nonlinear differential geometry theory was applied to transform the chaotic discrepancy system into canonical form. A feedback control for synchronizing two chaotic systems is proposed based on sliding mode control design. To make this controller physically realizable, an extended state observer is used to estimate the error between the transmitter and receiver. Two illustrative examples were carried out: (1) The Chua oscillator was used to show that synchronization was achieved and the message signal was recovered in spite of parametric variations; (2) Two second-order driven oscillators were presented to show that the synchronization can be achieved and that the message can be recovered in spite of the strictly different model.展开更多
Background: Despite their utility in accessing ambulatory movement, pedometers have not been used consistently to monitor physical activity in U.S. surveillance systems. This study was designed to determine the feasib...Background: Despite their utility in accessing ambulatory movement, pedometers have not been used consistently to monitor physical activity in U.S. surveillance systems. This study was designed to determine the feasibility of using pedometers to assess daily steps taken in a sub-sample of adults from Maricopa County who completed the 2014 Arizona Behavioral Risk Factor Surveillance System Survey.Methods: Respondents were sent an Omron HJ324 U pedometer, a logbook to record steps taken, and a walking questionnaire. The pedometer was worn for 7 days. Feasibility was assessed for acceptability(interest in study), demand(procedures followed correctly), implementation(time to complete study), and practicality(cost).Results: Acceptability was modest with 23.9%(830/3476) agreeing to participate. Among those participating(92.9%; 771/830), 50.1%(386/771)returned the logbook. Demand was modest with 39.3%(303/771) of logbooks returned with valid data. Implementation represented 5 months to recruit participants. The cost to obtain valid step-count data was USD61.60 per person. An average of 6363 ± 3049 steps/day were taken with most participants classified as sedentary(36.0%) or low active(35.6%).Conclusion: The feasibility of using pedometers in a state-based surveillance system is modest at best. Feasibility may potentially be improved with easy-to-use pedometers where data can be electronically downloaded.展开更多
The purpose of this paper is to present and evaluate a method of free gait generation for HITCRI,a hexapod walking robot.The HITCR-I is designed as a modularized structure of legs that is based upon a four-bar linkage...The purpose of this paper is to present and evaluate a method of free gait generation for HITCRI,a hexapod walking robot.The HITCR-I is designed as a modularized structure of legs that is based upon a four-bar linkage mechanism and with force sensors in the tip of legs,distributed hardware structure and a modular software structure of the control system.Based on a set of local rules between adjacent legs,finite state machine(FSM) model is built to control the coordination of legs.An automatic smooth transition of gait pattern is achieved through deriving the mathematical relation between gait pattern and locomotion parameters.The disordered inter-leg phase sequence is adjusted to a regular state smoothly and quickly by the local rules based FSM,and the gait pattern can transform automatically adapting to irregular terrain.The experiment on HITCR-I has demonstrated that it can walk through irregular terrain reliably and expeditiously with the free gait controller designed in this paper.展开更多
基金Project (No. 20040146) supported by Zhejiang Provincial Edu-cation Department Foundation, China
文摘This paper deals with the synchronization of chaotic systems with structure or parameters difference. Nonlinear differential geometry theory was applied to transform the chaotic discrepancy system into canonical form. A feedback control for synchronizing two chaotic systems is proposed based on sliding mode control design. To make this controller physically realizable, an extended state observer is used to estimate the error between the transmitter and receiver. Two illustrative examples were carried out: (1) The Chua oscillator was used to show that synchronization was achieved and the message signal was recovered in spite of parametric variations; (2) Two second-order driven oscillators were presented to show that the synchronization can be achieved and that the message can be recovered in spite of the strictly different model.
基金partially supported under a contract from Mc King Consulting(#4568)with the U.S.Centers for Disease Control and Prevention(200-2012-F-53729)to assist with pedometer distribution
文摘Background: Despite their utility in accessing ambulatory movement, pedometers have not been used consistently to monitor physical activity in U.S. surveillance systems. This study was designed to determine the feasibility of using pedometers to assess daily steps taken in a sub-sample of adults from Maricopa County who completed the 2014 Arizona Behavioral Risk Factor Surveillance System Survey.Methods: Respondents were sent an Omron HJ324 U pedometer, a logbook to record steps taken, and a walking questionnaire. The pedometer was worn for 7 days. Feasibility was assessed for acceptability(interest in study), demand(procedures followed correctly), implementation(time to complete study), and practicality(cost).Results: Acceptability was modest with 23.9%(830/3476) agreeing to participate. Among those participating(92.9%; 771/830), 50.1%(386/771)returned the logbook. Demand was modest with 39.3%(303/771) of logbooks returned with valid data. Implementation represented 5 months to recruit participants. The cost to obtain valid step-count data was USD61.60 per person. An average of 6363 ± 3049 steps/day were taken with most participants classified as sedentary(36.0%) or low active(35.6%).Conclusion: The feasibility of using pedometers in a state-based surveillance system is modest at best. Feasibility may potentially be improved with easy-to-use pedometers where data can be electronically downloaded.
基金Supported by the National High Technology Research and Development Programme of China(No.2007AA041550)the National NaturalScience Foundation of China(No.51105101)
文摘The purpose of this paper is to present and evaluate a method of free gait generation for HITCRI,a hexapod walking robot.The HITCR-I is designed as a modularized structure of legs that is based upon a four-bar linkage mechanism and with force sensors in the tip of legs,distributed hardware structure and a modular software structure of the control system.Based on a set of local rules between adjacent legs,finite state machine(FSM) model is built to control the coordination of legs.An automatic smooth transition of gait pattern is achieved through deriving the mathematical relation between gait pattern and locomotion parameters.The disordered inter-leg phase sequence is adjusted to a regular state smoothly and quickly by the local rules based FSM,and the gait pattern can transform automatically adapting to irregular terrain.The experiment on HITCR-I has demonstrated that it can walk through irregular terrain reliably and expeditiously with the free gait controller designed in this paper.
