岩屑图像分割要求精度高、速度快和鲁棒性强。针对这些要求,提出了基于SLIC(simple linear iterative clustering)和动态区域合并的分割算法。SLIC算法能产生形状规则、大小均匀、排列紧凑的超像素区域;但是SLIC分割后的图像过分割问题...岩屑图像分割要求精度高、速度快和鲁棒性强。针对这些要求,提出了基于SLIC(simple linear iterative clustering)和动态区域合并的分割算法。SLIC算法能产生形状规则、大小均匀、排列紧凑的超像素区域;但是SLIC分割后的图像过分割问题严重,为了降低过分割率,提出了基于NNR的动态区域合并算法,将超像素区域进行相似性合并。实验结果表明,将该算法用于岩屑颗粒图像分割,能够取得较好的效果。展开更多
The jet structure of the Southern Ocean front south of Australia is studied in stream-coordinate with a new altimeter product—Absolute Dynamic Topography (ADT) from AVISO. The accuracy of the ADT data is validated wi...The jet structure of the Southern Ocean front south of Australia is studied in stream-coordinate with a new altimeter product—Absolute Dynamic Topography (ADT) from AVISO. The accuracy of the ADT data is validated with the mooring data from a two-year subantarctic-front experiment. It is demonstrated that the ADT is consistent with in-situ measurements and captures the meso-scale activity of the Antarctic Circumpolar Current (ACC). Stream-coordinate analysis of ADT surface geostrophic flows finds that ACC jets exhibit large spatio-temporal variability and do not correspond to particular streamfunction values. In the circumpolar scope ACC jets display a transient fragmented pattern controlled by topographic features. The poleward shift of jet in streamfunction space, as revealed by a streamwise correlation method, indicates the presence of meridional fluxes of zonal momentum. Such cross-stream eddy fluxes concentrate the broad ACC baroclinic flow into narrow jets. Combined with a recent discovery of gravest empirical mode (GEM) in the thermohaline fields, the study clarifies the interrelationship among front, jet and streamfunction in the Southern Ocean.展开更多
A pneumatic parallel platform driven by an air cylinder and three circumambient pneumatic muscles was considered. Firstly, a mathematical model of the pneumatic servo system was developed for the MIMO nonlinear model-...A pneumatic parallel platform driven by an air cylinder and three circumambient pneumatic muscles was considered. Firstly, a mathematical model of the pneumatic servo system was developed for the MIMO nonlinear model-based controller designed. The pneumatic muscles were controlled by three proportional position valves, and the air cylinder was controlled by a proportional pressure valve. As the forward kinematics of this structure had no analytical solution, the control strategy should be designed in joint space. A cross-coupling integral adaptive robust controller(CCIARC) which combined cross-coupling control strategy and traditional adaptive robust control(ARC) theory was developed by back-stepping method to accomplish trajectory tracking control of the parallel platform. The cross-coupling part of the controller stabilized the length error in joint space as well as the synchronization error, and the adaptive robust control part attenuated the adverse effects of modelling error and disturbance. The force character of the pneumatic muscles was difficult to model precisely, so the on-line recursive least square estimation(RLSE) method was employed to modify the model compensation. The projector mapping method was used to condition the RLSE algorithm to bound the parameters estimated. An integral feedback part was added to the traditional robust function to reduce the negative influence of the slow time-varying characteristic of pneumatic muscles and enhance the ability of trajectory tracking. The stability of the controller designed was proved through Laypunov's theory. Various contrast controllers were designed to testify the newly designed components of the CCIARC. Extensive experiments were conducted to illustrate the performance of the controller.展开更多
We report the results on anisotropic flows and their scaling forφmesons andΩ(Ω^-+■^+)baryons in Au+Au collisions at RHIC,obtained from a dynamical quark coalescence model that uses the quark phase- space informati...We report the results on anisotropic flows and their scaling forφmesons andΩ(Ω^-+■^+)baryons in Au+Au collisions at RHIC,obtained from a dynamical quark coalescence model that uses the quark phase- space information from a multi-phase transport(AMPT)model within the string melting scenario and includes the quark structure of hadrons.展开更多
文摘岩屑图像分割要求精度高、速度快和鲁棒性强。针对这些要求,提出了基于SLIC(simple linear iterative clustering)和动态区域合并的分割算法。SLIC算法能产生形状规则、大小均匀、排列紧凑的超像素区域;但是SLIC分割后的图像过分割问题严重,为了降低过分割率,提出了基于NNR的动态区域合并算法,将超像素区域进行相似性合并。实验结果表明,将该算法用于岩屑颗粒图像分割,能够取得较好的效果。
基金Supported by the National Basic Research Program of China (973 Program) (Nos.2006CB403601,2007CB411804)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-YW-Q11-02)the National Natural Sciences Foundation of China (No.40776014)
文摘The jet structure of the Southern Ocean front south of Australia is studied in stream-coordinate with a new altimeter product—Absolute Dynamic Topography (ADT) from AVISO. The accuracy of the ADT data is validated with the mooring data from a two-year subantarctic-front experiment. It is demonstrated that the ADT is consistent with in-situ measurements and captures the meso-scale activity of the Antarctic Circumpolar Current (ACC). Stream-coordinate analysis of ADT surface geostrophic flows finds that ACC jets exhibit large spatio-temporal variability and do not correspond to particular streamfunction values. In the circumpolar scope ACC jets display a transient fragmented pattern controlled by topographic features. The poleward shift of jet in streamfunction space, as revealed by a streamwise correlation method, indicates the presence of meridional fluxes of zonal momentum. Such cross-stream eddy fluxes concentrate the broad ACC baroclinic flow into narrow jets. Combined with a recent discovery of gravest empirical mode (GEM) in the thermohaline fields, the study clarifies the interrelationship among front, jet and streamfunction in the Southern Ocean.
基金Project(51375430)supported by the National Natural Science Foundation of China
文摘A pneumatic parallel platform driven by an air cylinder and three circumambient pneumatic muscles was considered. Firstly, a mathematical model of the pneumatic servo system was developed for the MIMO nonlinear model-based controller designed. The pneumatic muscles were controlled by three proportional position valves, and the air cylinder was controlled by a proportional pressure valve. As the forward kinematics of this structure had no analytical solution, the control strategy should be designed in joint space. A cross-coupling integral adaptive robust controller(CCIARC) which combined cross-coupling control strategy and traditional adaptive robust control(ARC) theory was developed by back-stepping method to accomplish trajectory tracking control of the parallel platform. The cross-coupling part of the controller stabilized the length error in joint space as well as the synchronization error, and the adaptive robust control part attenuated the adverse effects of modelling error and disturbance. The force character of the pneumatic muscles was difficult to model precisely, so the on-line recursive least square estimation(RLSE) method was employed to modify the model compensation. The projector mapping method was used to condition the RLSE algorithm to bound the parameters estimated. An integral feedback part was added to the traditional robust function to reduce the negative influence of the slow time-varying characteristic of pneumatic muscles and enhance the ability of trajectory tracking. The stability of the controller designed was proved through Laypunov's theory. Various contrast controllers were designed to testify the newly designed components of the CCIARC. Extensive experiments were conducted to illustrate the performance of the controller.
基金Supported by National Natural Science Foundation of China (10575071,10675082)MOE of China under Project NCET-05-0392,Shanghai Rising-Star Program (06QA14024)+1 种基金SRF for ROCS,SEM of China (LWC) as well as by the US National Science Foundation (PHY-0457265)the Welch Foundation (A-1358 (CMK))
文摘We report the results on anisotropic flows and their scaling forφmesons andΩ(Ω^-+■^+)baryons in Au+Au collisions at RHIC,obtained from a dynamical quark coalescence model that uses the quark phase- space information from a multi-phase transport(AMPT)model within the string melting scenario and includes the quark structure of hadrons.
