This paper presents an urban expressway video surveillance and monitoring system for traffic flow measurement and abnormal performance detection. The proposed flow detection module collects traffic flow statistics in ...This paper presents an urban expressway video surveillance and monitoring system for traffic flow measurement and abnormal performance detection. The proposed flow detection module collects traffic flow statistics in real time by leveraging multi-vehicle tracking information. Based on these online statistics, road operating situations can be easily obtained. Using spatiotemporal trajectories, vehicle motion paths are encoded by hidden Markov models. With path division and parameter matching, abnormal performances containing extra low or high speed driving, illegal stopping and turning are detected in real scenes. The traffic surveillance approach is implemented and evaluated on a DM642 DSP-based embedded platform. Experimental results demonstrate that the proposed system is feasible for the detection of vehicle speed, vehicle counts and road efficiency, and it is effective for the monitoring of the aforementioned anomalies with low computational costs.展开更多
El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate s...El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.展开更多
External forces of marine weather, such as waves, currents and wind flows, affect the course and speed of a ship under way. As a result, marine accidents, such as collisions or grounding, may occur, particularly in in...External forces of marine weather, such as waves, currents and wind flows, affect the course and speed of a ship under way. As a result, marine accidents, such as collisions or grounding, may occur, particularly in inshore areas. On coasts where earthquakes and tsunamis occur frequently, such as the Japanese coast, a tsunami that advances into a bay from the open sea is influenced by the submarine topography. It grows into a huge wave that could cause tremendous damage to ships under way and at anchorage. A massive earthquake occurred in the Tohoku and Kanto regions of Japan on March 11,2011. In response, a tsunami alert, a tsunami warning and an advisory were issued for the entire Pacific coast region. This research investigates the evacuation behaviour of ships by AIS （automatic identification system） data in Tokyo Bay after the tsunami warning was issued. The unusual behaviour observed was attributed to the emergency evacuation of ships.展开更多
The active transmission of information from sender to receiver is a fundamental component of communication, and is therefore a primary facet in evolutionary models of sexual selection. Research in several systems has ...The active transmission of information from sender to receiver is a fundamental component of communication, and is therefore a primary facet in evolutionary models of sexual selection. Research in several systems has underlined the importance of multiple sensory modalities in courtship signals. However, we still tend to think of individuals as having a relatively static signal in consecutive communicative events. While this may be true for certain traits such as body size or coloration, behaviorally modulated signals can quickly violate this assumption. In this work, we explore how intraspecific variation may be an important component of interspecific signal divergence using cichlid fishes from Lake Malawi. Behavioral analyses were made using six species of Malawian cichlids from two divergent genera. While interspecific differences were found between congeners based on species-level analyses of both acoustic and audiovisual signals, intraspecific variation was of a similar magnitude. Specifically, individual fishes were found to possess highly plastic signal repertoires. This finding was ubiquitous across all species and resuited in a great deal of overlap between heterospecific individuals, despite statistically distinct species means. These results demonstrate that some aspects of courtship in Malawian cichlids are more plastic than previously proposed, and that studies must account for signal variability within individuals. We propose here that behavioral variability in signaling is important in determining the communication landscape on which signals are perceived. We review potential complexity deriving from multimodal signaling, discuss the sources for such lability, and suggest ways in which this issue may be approached experimentally .展开更多
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2009BAG13A04)Jiangsu Transportation Science Research Program(No.08X09)Program of Suzhou Science and Technology(No.SG201076)
文摘This paper presents an urban expressway video surveillance and monitoring system for traffic flow measurement and abnormal performance detection. The proposed flow detection module collects traffic flow statistics in real time by leveraging multi-vehicle tracking information. Based on these online statistics, road operating situations can be easily obtained. Using spatiotemporal trajectories, vehicle motion paths are encoded by hidden Markov models. With path division and parameter matching, abnormal performances containing extra low or high speed driving, illegal stopping and turning are detected in real scenes. The traffic surveillance approach is implemented and evaluated on a DM642 DSP-based embedded platform. Experimental results demonstrate that the proposed system is feasible for the detection of vehicle speed, vehicle counts and road efficiency, and it is effective for the monitoring of the aforementioned anomalies with low computational costs.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB955202and2012CB41740)the National Natural Science Foundation of China(Grant Nos.41075064,41176014,and41006016)
文摘El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.
文摘External forces of marine weather, such as waves, currents and wind flows, affect the course and speed of a ship under way. As a result, marine accidents, such as collisions or grounding, may occur, particularly in inshore areas. On coasts where earthquakes and tsunamis occur frequently, such as the Japanese coast, a tsunami that advances into a bay from the open sea is influenced by the submarine topography. It grows into a huge wave that could cause tremendous damage to ships under way and at anchorage. A massive earthquake occurred in the Tohoku and Kanto regions of Japan on March 11,2011. In response, a tsunami alert, a tsunami warning and an advisory were issued for the entire Pacific coast region. This research investigates the evacuation behaviour of ships by AIS （automatic identification system） data in Tokyo Bay after the tsunami warning was issued. The unusual behaviour observed was attributed to the emergency evacuation of ships.
文摘The active transmission of information from sender to receiver is a fundamental component of communication, and is therefore a primary facet in evolutionary models of sexual selection. Research in several systems has underlined the importance of multiple sensory modalities in courtship signals. However, we still tend to think of individuals as having a relatively static signal in consecutive communicative events. While this may be true for certain traits such as body size or coloration, behaviorally modulated signals can quickly violate this assumption. In this work, we explore how intraspecific variation may be an important component of interspecific signal divergence using cichlid fishes from Lake Malawi. Behavioral analyses were made using six species of Malawian cichlids from two divergent genera. While interspecific differences were found between congeners based on species-level analyses of both acoustic and audiovisual signals, intraspecific variation was of a similar magnitude. Specifically, individual fishes were found to possess highly plastic signal repertoires. This finding was ubiquitous across all species and resuited in a great deal of overlap between heterospecific individuals, despite statistically distinct species means. These results demonstrate that some aspects of courtship in Malawian cichlids are more plastic than previously proposed, and that studies must account for signal variability within individuals. We propose here that behavioral variability in signaling is important in determining the communication landscape on which signals are perceived. We review potential complexity deriving from multimodal signaling, discuss the sources for such lability, and suggest ways in which this issue may be approached experimentally .
