Crowd density estimation in wide areas is a challenging problem for visual surveillance. Because of the high risk of degeneration, the safety of public events involving large crowds has always been a major concern. In...Crowd density estimation in wide areas is a challenging problem for visual surveillance. Because of the high risk of degeneration, the safety of public events involving large crowds has always been a major concern. In this paper, we propose a video-based crowd density analysis and prediction system for wide-area surveillance applications. In monocular image sequences, the Accumulated Mosaic Image Difference (AMID) method is applied to extract crowd areas having irregular motion. The specific number of persons and velocity of a crowd can be adequately estimated by our system from the density of crowded areas. Using a multi-camera network, we can obtain predictions of a crowd's density several minutes in advance. The system has been used in real applications, and numerous experiments conducted in real scenes (station, park, plaza) demonstrate the effectiveness and robustness of the proposed method.展开更多
Crowd density is an important factor of crowd stability.Previous crowd density estimation methods are highly dependent on the specific video scene.This paper presented a video scene invariant crowd density estimation ...Crowd density is an important factor of crowd stability.Previous crowd density estimation methods are highly dependent on the specific video scene.This paper presented a video scene invariant crowd density estimation method using Geographic Information Systems(GIS) to monitor crowd size for large areas.The proposed method mapped crowd images to GIS.Then we can estimate crowd density for each camera in GIS using an estimation model obtained by one camera.Test results show that one model obtained by one camera in GIS can be adaptively applied to other cameras in outdoor video scenes.A real-time monitoring system for crowd size in large areas based on scene invariant model has been successfully used in 'Jiangsu Qinhuai Lantern Festival,2012'.It can provide early warning information and scientific basis for safety and security decision making.展开更多
We consider the Cauchy problem, free boundary problem and piston problem for one-dimensional compressible Navier-Stokes equations with density-dependent viscosity. Using the reduction to absurdity method, we prove tha...We consider the Cauchy problem, free boundary problem and piston problem for one-dimensional compressible Navier-Stokes equations with density-dependent viscosity. Using the reduction to absurdity method, we prove that the weak solutions to these systems do not exhibit vacuum states, provided that no vacuum states are present initially. The essential re- quirements on the solutions are that the mass and energy of the fluid are locally integrable at each time, and the Lloc1-norm of the velocity gradient is locally integrable in time.展开更多
We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises. The expression of the stationary probability distribution function （SPDF） i...We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises. The expression of the stationary probability distribution function （SPDF） is analytically derived by means of mean-field approximation, and verified by stochastic simulations. The results indicate that： （i） A noise amplitude （a0）, a noise autocorrelation time （τ0） and a noise symmetry parameter （k） all can affect the SPDF; （ii） There is an optimal τ0, which makes the mean value of population density be maximal, near which a transition takes place, i.e., the stationary mean value of species density （（x）st） suddenly falls to a lower constant, （iii） As k decreases, the maximum of （x）xt and the optimal 70 increase. The parameter planes of TO -- a20 and τ0- k for the transition are plotted.展开更多
Field experiments were conducted using Ceranock bait station, ＂attract and kill＂ system to combat Mediterranean fruit fly, Ceratitis capitata, in citrus orchards of Baghdad and Wasit governorates, Iraq, during 2013-...Field experiments were conducted using Ceranock bait station, ＂attract and kill＂ system to combat Mediterranean fruit fly, Ceratitis capitata, in citrus orchards of Baghdad and Wasit governorates, Iraq, during 2013-2014 season. Control program was implemented in six citrus orchards of mixed citrus varieties： Orange, Citrus sinensis; Mandarin, C. reticulate; Lemon, C. lemon; and Bergamot, C. aurantium. Ceranock traps 240/ha were hanged in trees of two separate orchards in each location, with third orchard served as control. Delta and McPhail traps supplied with pheromone were used to monitor Medfly population density in treated and control orchards. Results indicated that Medfly activity and presence in citrus orchards started during the first week of October coincide with the beginning of fruits ripening. The result indicated that Medfly population density in Wasit orchards was more than that of Baghdad orchards. The total trapped insects after two weeks of Ceranock were 59, 94, 142 and 205, 277, 765 adults for the firsst, second and the control orchards in the two locations, respectively. The percentage of fruit injuries were increased dramatically when fruits mature and its color turn to yellowish reaching of 35%, 56%, 21% and 32% in mandarin and orange fruits in Baghdad and Wasit orchards, respectively, compared with 3%, 4%, 4% and 5% in treated orchards, respectively. Calculated percentage of fruit damage indicated that reduction in injuries were 97% in mandarin and 96% in orange at Baghdad orchards and were 95% and 96%, respectively, in Wasit orchards. The results of this study demonstrate clearly the efficacy of Ceranock bait station, ＂attract and kill＂ system as a control measure for Medfly in citrus orchards.展开更多
基金supported by the National Natural Science Foundation of China under Grant No. 61175007the National Key Technologies R&D Program under Grant No. 2012BAH07B01the National Key Basic Research Program of China (973 Program) under Grant No. 2012CB316302
文摘Crowd density estimation in wide areas is a challenging problem for visual surveillance. Because of the high risk of degeneration, the safety of public events involving large crowds has always been a major concern. In this paper, we propose a video-based crowd density analysis and prediction system for wide-area surveillance applications. In monocular image sequences, the Accumulated Mosaic Image Difference (AMID) method is applied to extract crowd areas having irregular motion. The specific number of persons and velocity of a crowd can be adequately estimated by our system from the density of crowded areas. Using a multi-camera network, we can obtain predictions of a crowd's density several minutes in advance. The system has been used in real applications, and numerous experiments conducted in real scenes (station, park, plaza) demonstrate the effectiveness and robustness of the proposed method.
基金The authors would like to thank the reviewers for their detailed reviews and constructive comments. We are also grateful for Sophie Song＇s help on the improving English. This work was supported in part by the ‘Fivetwelfh＇ National Science and Technology Support Program of the Ministry of Science and Technology of China （No. 2012BAH35B02）, the National Natural Science Foundation of China （NSFC） （No. 41401107, No. 41201402, and No. 41201417）.
文摘Crowd density is an important factor of crowd stability.Previous crowd density estimation methods are highly dependent on the specific video scene.This paper presented a video scene invariant crowd density estimation method using Geographic Information Systems(GIS) to monitor crowd size for large areas.The proposed method mapped crowd images to GIS.Then we can estimate crowd density for each camera in GIS using an estimation model obtained by one camera.Test results show that one model obtained by one camera in GIS can be adaptively applied to other cameras in outdoor video scenes.A real-time monitoring system for crowd size in large areas based on scene invariant model has been successfully used in 'Jiangsu Qinhuai Lantern Festival,2012'.It can provide early warning information and scientific basis for safety and security decision making.
基金Project supported by the National Natural Science Foundation of China (No. 10571158) and the DFG
文摘We consider the Cauchy problem, free boundary problem and piston problem for one-dimensional compressible Navier-Stokes equations with density-dependent viscosity. Using the reduction to absurdity method, we prove that the weak solutions to these systems do not exhibit vacuum states, provided that no vacuum states are present initially. The essential re- quirements on the solutions are that the mass and energy of the fluid are locally integrable at each time, and the Lloc1-norm of the velocity gradient is locally integrable in time.
基金Supported by the Yunnan Provincial Foundation of China under Grant Nos.2009CD036 and 08Z0015the National Natural Science Foundations of China under Grant Nos.50734009 and 10865006
文摘We investigate statistical properties of multispecies competition ecosystems subjected to both symmetric and asymmetric dichotomous noises. The expression of the stationary probability distribution function （SPDF） is analytically derived by means of mean-field approximation, and verified by stochastic simulations. The results indicate that： （i） A noise amplitude （a0）, a noise autocorrelation time （τ0） and a noise symmetry parameter （k） all can affect the SPDF; （ii） There is an optimal τ0, which makes the mean value of population density be maximal, near which a transition takes place, i.e., the stationary mean value of species density （（x）st） suddenly falls to a lower constant, （iii） As k decreases, the maximum of （x）xt and the optimal 70 increase. The parameter planes of TO -- a20 and τ0- k for the transition are plotted.
文摘Field experiments were conducted using Ceranock bait station, ＂attract and kill＂ system to combat Mediterranean fruit fly, Ceratitis capitata, in citrus orchards of Baghdad and Wasit governorates, Iraq, during 2013-2014 season. Control program was implemented in six citrus orchards of mixed citrus varieties： Orange, Citrus sinensis; Mandarin, C. reticulate; Lemon, C. lemon; and Bergamot, C. aurantium. Ceranock traps 240/ha were hanged in trees of two separate orchards in each location, with third orchard served as control. Delta and McPhail traps supplied with pheromone were used to monitor Medfly population density in treated and control orchards. Results indicated that Medfly activity and presence in citrus orchards started during the first week of October coincide with the beginning of fruits ripening. The result indicated that Medfly population density in Wasit orchards was more than that of Baghdad orchards. The total trapped insects after two weeks of Ceranock were 59, 94, 142 and 205, 277, 765 adults for the firsst, second and the control orchards in the two locations, respectively. The percentage of fruit injuries were increased dramatically when fruits mature and its color turn to yellowish reaching of 35%, 56%, 21% and 32% in mandarin and orange fruits in Baghdad and Wasit orchards, respectively, compared with 3%, 4%, 4% and 5% in treated orchards, respectively. Calculated percentage of fruit damage indicated that reduction in injuries were 97% in mandarin and 96% in orange at Baghdad orchards and were 95% and 96%, respectively, in Wasit orchards. The results of this study demonstrate clearly the efficacy of Ceranock bait station, ＂attract and kill＂ system as a control measure for Medfly in citrus orchards.
