Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect ...Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect delay. The technique decouples the stochastic interconnect segments by an improved decoupling method. Combined with a polynomial chaos expression （PCE）, this paper applies the stochastic Galerkin method （SGM） to analyze the system response. A finite representation of interconnect delay is then obtained with the complex approximation method and the bisection method. Results from the analysis match well with those from SPICE. Moreover, the method shows good computational efficiency, as the running time is much less than the SPICE simulation＇s.展开更多
To enhance machining efficiency,tool change time has to be reduced.Thus,for an automatic tool changer attached to a machining center,the tool change time is to be reduced.Also the automatic tool changer is a main part...To enhance machining efficiency,tool change time has to be reduced.Thus,for an automatic tool changer attached to a machining center,the tool change time is to be reduced.Also the automatic tool changer is a main part of the machining center as a driving source.The static attributes of the automatic tool changer using the commercial code,ANSYS Workbench V12,were tried to interpret.And the optimum design of automatic tool changer arm was proposed by performing the multi-stage optimum design.The shape optimization of the automatic tool changer was proposed and the result was verified to obtain acceptable improvements.It is possible to obtain an optimized model in which the maximum deformation,maximum stress,and mass are reduced by 10.46%,12.89% and 9.26%,respectively,compared with those of the initial model.Also,the results between conventional method by the design of experiments and proposed method by the multi-stage optimum design method were compared.展开更多
This paper proposed a modified artificial physics(AP)method to solve the autonomous navigation problem for mobile robots in complex environments.The basic AP method tends to cause oscillations in the presence of obsta...This paper proposed a modified artificial physics(AP)method to solve the autonomous navigation problem for mobile robots in complex environments.The basic AP method tends to cause oscillations in the presence of obstacles and in narrow passages,which can result in time consumption.To alleviate oscillation,we modified the AP method using the Levenbery-Marquardt(LM)algorithm.In the modified AP method,we altered the original directions of AP forces to the Newton direction,and adjust the parameter by the LM algorithm.A series of comparative experimental results show that the modified AP method can achieve smoother trajectories with less time consumption.This demonstrates the feasibility and effectiveness of our proposed approach.展开更多
文摘Process variations can reduce the accuracy in estimation of interconnect performance. This work presents a process variation based stochastic model and proposes an effective analytical method to estimate interconnect delay. The technique decouples the stochastic interconnect segments by an improved decoupling method. Combined with a polynomial chaos expression （PCE）, this paper applies the stochastic Galerkin method （SGM） to analyze the system response. A finite representation of interconnect delay is then obtained with the complex approximation method and the bisection method. Results from the analysis match well with those from SPICE. Moreover, the method shows good computational efficiency, as the running time is much less than the SPICE simulation＇s.
基金Work(RTI04-01-03) supported by Grant from Regional Technology Innovation Program of the Ministry of Knowledge Economy (MKE),Korea
文摘To enhance machining efficiency,tool change time has to be reduced.Thus,for an automatic tool changer attached to a machining center,the tool change time is to be reduced.Also the automatic tool changer is a main part of the machining center as a driving source.The static attributes of the automatic tool changer using the commercial code,ANSYS Workbench V12,were tried to interpret.And the optimum design of automatic tool changer arm was proposed by performing the multi-stage optimum design.The shape optimization of the automatic tool changer was proposed and the result was verified to obtain acceptable improvements.It is possible to obtain an optimized model in which the maximum deformation,maximum stress,and mass are reduced by 10.46%,12.89% and 9.26%,respectively,compared with those of the initial model.Also,the results between conventional method by the design of experiments and proposed method by the multi-stage optimum design method were compared.
基金supported by the National Natural Science Foundation of China(Grant Nos.61273054 and 61333004)the National Key Basic Research Program of China(Grant No.2014CB046401)+2 种基金the Program for New Century Excellent Talents in University of China(Grant No.NCET-10-0021)the Top-Notch Young Talents Program of China,Graduate Innovation Foundation for Beihang University(Grant No.YCSJ-01-201206)Aeronautical Foundation of China(Grant No.20135851042)
文摘This paper proposed a modified artificial physics(AP)method to solve the autonomous navigation problem for mobile robots in complex environments.The basic AP method tends to cause oscillations in the presence of obstacles and in narrow passages,which can result in time consumption.To alleviate oscillation,we modified the AP method using the Levenbery-Marquardt(LM)algorithm.In the modified AP method,we altered the original directions of AP forces to the Newton direction,and adjust the parameter by the LM algorithm.A series of comparative experimental results show that the modified AP method can achieve smoother trajectories with less time consumption.This demonstrates the feasibility and effectiveness of our proposed approach.
