To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and a...To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and according to spatial geometric properties of tool path and the kinematics theory, maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system, a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves productivity greatly.展开更多
Online traffic simulation that feeds from online information to simulate vehicle movement in real-time has recently seen substantial advancement in the development of intelligent transportation systems and urban traff...Online traffic simulation that feeds from online information to simulate vehicle movement in real-time has recently seen substantial advancement in the development of intelligent transportation systems and urban traffic management.It has been a challenging problem due to three aspects:1)The diversity of traffic patterns due to heterogeneous layouts of urban intersections;2)The nature of complex spatiotemporal correlations;3)The requirement of dynamically adjusting the parameters of traffic models in a real-time system.To cater to these challenges,this paper proposes an online traffic simulation framework called automated urban traffic operation simulation via meta-learning(AUTOSIM).In particular,simulation models with various intersection layouts are automatically generated using an open-source simulation tool based on static traffic geometry attributes.Through a meta-learning technique,AUTOSIM enables an automated learning process for dynamic model settings of traffic scenarios featured with different spatiotemporal correlations.Besides,AUTOSIM is capable of adapting traffic model parameters according to dynamic traffic information in real-time by using a meta-learner.Through computational experiments,we demonstrate the effectiveness of the meta-learningbased framework that is capable of providing reliable supports to real-time traffic simulation and dynamic traffic operations.展开更多
A multi-standard compatible transmitter with pre-emphasis for high speed serial links is presented. Based on the comparison between voltage mode（VM） and current mode（CM） output driver architectures,a low power CM ...A multi-standard compatible transmitter with pre-emphasis for high speed serial links is presented. Based on the comparison between voltage mode（VM） and current mode（CM） output driver architectures,a low power CM output driver with reverse scaling and bias current filtering technique is proposed.A 2-tap pre-emphasis filter is used to reduce the intersymbol interference caused by the low-pass channel,and a high speed,low power combined serializer is implemented to convert 10 bit parallel data into a serial data stream.The whole transmitter is fabricated in 65 nm 1.2 V/2.5 V CMOS technology.It provides an eye height greater than 800 mV for data rates of both 2.5 Gb/s and 5 Gb/s.The output root mean square jitter of the transmitter at 5 Gb/s is only 9.94 ps without pre-emphasis.The transmitter consumes 41.2 mA at 5 Gb/s and occupies only 240×140μm^2.展开更多
基金This project is supported by National Hi-tech Research and Development Program of China (863 Program, No. 2002AA421150)Specialized Re-search Fund for Doctor Program of Higher Education of China (No. 20030335091).
文摘To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and according to spatial geometric properties of tool path and the kinematics theory, maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system, a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves productivity greatly.
基金supported by the National Natural Science Foundation of China(62173329)。
文摘Online traffic simulation that feeds from online information to simulate vehicle movement in real-time has recently seen substantial advancement in the development of intelligent transportation systems and urban traffic management.It has been a challenging problem due to three aspects:1)The diversity of traffic patterns due to heterogeneous layouts of urban intersections;2)The nature of complex spatiotemporal correlations;3)The requirement of dynamically adjusting the parameters of traffic models in a real-time system.To cater to these challenges,this paper proposes an online traffic simulation framework called automated urban traffic operation simulation via meta-learning(AUTOSIM).In particular,simulation models with various intersection layouts are automatically generated using an open-source simulation tool based on static traffic geometry attributes.Through a meta-learning technique,AUTOSIM enables an automated learning process for dynamic model settings of traffic scenarios featured with different spatiotemporal correlations.Besides,AUTOSIM is capable of adapting traffic model parameters according to dynamic traffic information in real-time by using a meta-learner.Through computational experiments,we demonstrate the effectiveness of the meta-learningbased framework that is capable of providing reliable supports to real-time traffic simulation and dynamic traffic operations.
基金Project supported by the National High Technology Research and Development Program of China(No.2011AA010403)the National Natural Science Foundation of China(No.60801045)
文摘A multi-standard compatible transmitter with pre-emphasis for high speed serial links is presented. Based on the comparison between voltage mode（VM） and current mode（CM） output driver architectures,a low power CM output driver with reverse scaling and bias current filtering technique is proposed.A 2-tap pre-emphasis filter is used to reduce the intersymbol interference caused by the low-pass channel,and a high speed,low power combined serializer is implemented to convert 10 bit parallel data into a serial data stream.The whole transmitter is fabricated in 65 nm 1.2 V/2.5 V CMOS technology.It provides an eye height greater than 800 mV for data rates of both 2.5 Gb/s and 5 Gb/s.The output root mean square jitter of the transmitter at 5 Gb/s is only 9.94 ps without pre-emphasis.The transmitter consumes 41.2 mA at 5 Gb/s and occupies only 240×140μm^2.
