State feedback impulsive modeling and dynamic analysis of ecological balance in aquaculture water with nutritional utilization rate Abstract   With the development of industry pollution, water bloom caused by nutriment distribution has become a serious problem which has perplexed biologists for a long time. The plankton population increase, which is influenced a lot by nutritional utilization rate, can be expressed best with Q. Cuixe2x80x99s model. The authors carry out a state feedback impulsive model to describe the control of investing fries and harvesting adult fish which is assisted with the plankton population regulation. The existence of order1 and order2 periodic solutions are studied, and their stabilities are discussed in addition. In the end, the numerical simulations show some specific cases of periodic solution and their biological meanings are put forward.

Cooperative decentralised circumnavigation with application to algal bloom tracking Harmful algal blooms occur frequently and deteriorate water quality. A reliable method is proposed in this paper to track algal blooms using a set of autonomous surface robots. A satellite image indicates the existence and initial location of the algal bloom for the deployment of the robot system. The algal bloom area is approximated by a circle with time varying location and size. This circle is estimated and circumnavigated by the robots which are able to locally sense its boundary. A multiagent control algorithm is proposed for the continuous monitoring of the dynamic evolution of the algal bloom. Such algorithm comprises of a decentralised least squares estimation of the target and a controller for circumnavigation. We prove the convergence of the robots to the circle and in equally spaced positions around it. Simulation results with data provided by the SINMOD ocean model are used to illustrate the theoretical results.