Research On Compound Event Coverage Problem In Wireless Sensor Networks

Wireless sensor networks(WSNs)have been widely used in event monitoring.It is also the basis for event monitoring.Due to the complex and variable application environment of WSNs,there are many technical difficulties in the application of event monitoring.For example,multi-constrained complex environment processing,limited sensor resource allocation,the confidence merging of compound events,the network deployment in different monitoring scenes,and the repair of event coverage holes.Based on the related work at home and abroad,this dissertation has carried out in-depth research on the compound event coverage in multi-constrained environment.The main work and innovations of this dissertation are as follows:Aiming at the confidence merging of compound events in WSNs,the relationship between sub-events and compound events is defined.At the same time,an event model based on joint probability is proposed to solve the confidence of compound events.Then,a compound event barrier coverage model is proposed for the multi-constrained application environment.Finally,a compound event barrier coverage algorithm based on Pareto optimality is proposed.The proposed algorithm effectively solves the compound event barrier coverage problem in multi-constrained sensor networks which is based on Pareto optimality mechanism,mutation operation,automatic adjustment mechanism,adaptive crossover mechanism and population update mechanism.A three-dimensional compound event model is proposed for three-dimensional monitoring scene which effectively defines the event monitoring problem in three-dimensional scene and takes into account the space constraints.Then,it is difficult to select penalty parameters for the traditional penalty function method,which directly affects the performance of the algorithm.Therefore,a three-dimensional model is proposed for compound event barrier coverage.The traditional event barrier coverage methods are easy to ignore the infeasible solution with small constraint violation degree.Therefore,a three-dimensional compound event barrier coverage algorithm is proposed.The proposed algorithm effectively preserves the high quality infeasible solution,which ensures the diversity of the population and enhances the performance of the compound event coverage.Traditional event deployment algorithms have the problem that the objective function is not continuously differentiable.Therefore,a multi-constrained compound event deployment model is proposed.The proposed model transforms the complex event deployment problem into two single-objective sub-problems.Both of sub-problems are continuously differentiable.The two sub-problems are applied to solve the Pareto optimal solution and the optimal confidence respectively.Aiming at the poor adaptability of traditional event deployment methods,a compound event deployment algorithm is proposed.This method can effectively meet the event deployment requirements for different monitoring environment and constraints.In the multi-constrained monitoring environment,the event coverage holes are often caused by the changes of monitoring tasks and requirements.Therefore,a joint event coverage hole repair algorithm based on mobile robots is proposed to repair event coverage holes in WSNs.In order to improve the local repair effect of the network,a local repair algorithm is proposed based on confidence allocation strategy,distribution function and individual sorting strategy.Then,the differential evolution algorithm is used for global repair to ensure the diversity of the repair strategy.Manual redeployment takes a lot of money and time,which is highly dangerous for humans.If the sensors are randomly thrown by aircrafts to repair the network,the repair effect cannot be guaranteed and a lot of network resources will also be wasted.The experimental results show that the proposed algorithm on the basis of mobile robots can effectively overcome the above problems.This dissertation systematically studies the compound event barrier coverage problem,the three-dimensional compound event coverage problem,the compound event deployment problem and the event coverage hole repair problem in multi-constrained environment.A multi-constrained compound event coverage model and network coverage,deployment,and repair algorithms are proposed.Finally,the effectiveness and efficiency of the proposed methods are verified by simulation experiments and comparison experiments.