Synchronized movements （schooling） emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ （LLO） of a predator. Moreover, prey-fish moving close to each other...Synchronized movements （schooling） emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ （LLO） of a predator. Moreover, prey-fish moving close to each other may blur the elec- tro-sensory perception of predators. The aim of this review is to explore mechanisms associated with synchronous swimming that may have contributed to increased adaptation and as a consequence may have influenced the evolution of schooling. The evolu- tionary development of the inner ear and the LLO increased the capacity to detect potential prey, possibly leading to an increased potential for cannibalism in the shoal, but also helped small fish to avoid joining larger fish, resulting in size homogeneity and, accordingly, an increased capacity for moving in synchrony. Water-movements and incidental sound produced as by-product of locomotion （ISOL） may provide fish with potentially useful information during swimming, such as neighbour body-size, speed, and location. When many fish move close to one another ISOL will be energetic and complex. Quiet intervals will be few. Fish moving in synchrony will have the capacity to discontinue movements simultaneously, providing relatively quiet intervals to al- low the reception of potentially critical environmental signals. Besides, synchronized movements may facilitate auditory grouping of ISOL. Turning preference bias, well-functioning sense organs, good health, and skillful motor performance might be important to achieving an appropriate distance to school neighbors and aid the individual fish in reducing time spent in the comparatively less safe school periphery. Turning preferences in ancestral fish shoals might have helped fish to maintain groups and stay in for- mation, reinforcing aforementioned predator confusion mechanisms, which possibly played a role in the lateralization of the ver- tebrate brain [Current Zoology 58 （1）： 116-128, 2012].展开更多
This paper considers the pose synchronization problem of a group of moving rigid bodies under switching topologies where the dwell time of each topology may has no nonzero lower bound. The authors introduce an average...This paper considers the pose synchronization problem of a group of moving rigid bodies under switching topologies where the dwell time of each topology may has no nonzero lower bound. The authors introduce an average dwell time condition to characterize the length of time intervals in which the graphs are connected. By designing distributed control laws of angular velocity and linear velocity,the closed-loop dynamics of multiple rigid bodies with switching topologies can be converted into a hybrid dynamical system. The authors employ the Lyapunov stability theorem, and show that the pose synchronization can be reached under the average dwell time condition. Moreover, the authors investigate the pose synchronization problem of the leader-following model under a similar average dwell time condition. Simulation examples are given to illustrate the results.展开更多
文摘Synchronized movements （schooling） emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ （LLO） of a predator. Moreover, prey-fish moving close to each other may blur the elec- tro-sensory perception of predators. The aim of this review is to explore mechanisms associated with synchronous swimming that may have contributed to increased adaptation and as a consequence may have influenced the evolution of schooling. The evolu- tionary development of the inner ear and the LLO increased the capacity to detect potential prey, possibly leading to an increased potential for cannibalism in the shoal, but also helped small fish to avoid joining larger fish, resulting in size homogeneity and, accordingly, an increased capacity for moving in synchrony. Water-movements and incidental sound produced as by-product of locomotion （ISOL） may provide fish with potentially useful information during swimming, such as neighbour body-size, speed, and location. When many fish move close to one another ISOL will be energetic and complex. Quiet intervals will be few. Fish moving in synchrony will have the capacity to discontinue movements simultaneously, providing relatively quiet intervals to al- low the reception of potentially critical environmental signals. Besides, synchronized movements may facilitate auditory grouping of ISOL. Turning preference bias, well-functioning sense organs, good health, and skillful motor performance might be important to achieving an appropriate distance to school neighbors and aid the individual fish in reducing time spent in the comparatively less safe school periphery. Turning preferences in ancestral fish shoals might have helped fish to maintain groups and stay in for- mation, reinforcing aforementioned predator confusion mechanisms, which possibly played a role in the lateralization of the ver- tebrate brain [Current Zoology 58 （1）： 116-128, 2012].
基金supported by the National Natural Science Foundation of China under Grant Nos.61473189 and 61621003the National Key Basic Research Program of China(973 program)under Grant No.2014CB845302
文摘This paper considers the pose synchronization problem of a group of moving rigid bodies under switching topologies where the dwell time of each topology may has no nonzero lower bound. The authors introduce an average dwell time condition to characterize the length of time intervals in which the graphs are connected. By designing distributed control laws of angular velocity and linear velocity,the closed-loop dynamics of multiple rigid bodies with switching topologies can be converted into a hybrid dynamical system. The authors employ the Lyapunov stability theorem, and show that the pose synchronization can be reached under the average dwell time condition. Moreover, the authors investigate the pose synchronization problem of the leader-following model under a similar average dwell time condition. Simulation examples are given to illustrate the results.
