Optimization Scheme of Forming Linear WSN for Safety Monitoring in Railway Transportation

With the development of wireless sensing network, more and more applications have been deployed in the safety monitoring and in natural disasters prevention. The safety and disaster prevention systems have usually been laid out in linear network architecture, such as those of railway, motorway transportation and pipes. The background of the article is railway hazard goods transportation safety surveillance. The paper discusses about the network architecture of linear wireless sensor networks with multiple sink nodes, and proposes the grouping method of sink nodes and the formation scheme of networks. The scheme can re-establish a monitoring network when the train on the way is disconnected and re-grouped. The switching algorithm of group head nodes is put forward, so that the energy consumption of each node in the group is even. The optimal switching parameters for group head nodes are suggested by the simulation. Compared with the usual monitoring network, the method proposed enables the system life expectancy to prolong more than five times, and meets the monitoring requirements simultaneously

Bayesian Design of Tandem Networks for Distributed Detection With Multi-bit Sensor Decisions

We consider the problem of decentralized hypothesis testing under communication constraints in a topology where several peripheral nodes are arranged in tandem. Each node receives an observation and transmits a message to its successor, and the last node then decides which hypothesis is true. We assume that the observations at different nodes are, conditioned on the true hypothesis, independent and the channel between any two successive nodes is considered error-free but rate-constrained. We propose a cyclic numerical design algorithm for the design of nodes using a person-by-person methodology with the minimum expected error probability as a design criterion, where the number of communicated messages is not necessarily equal to the number of hypotheses. The number of peripheral nodes in the proposed method is in principle arbitrary and the information rate constraints are satisfied by quantizing the input of each node. The performance of the proposed method for different information rate constraints, in a binary hypothesis test, is compared to the optimum rate-one solution due to Swaszek and a method proposed by Cover, and it is shown numerically that increasing the channel rate can significantly enhance the performance of the tandem network. Simulation results for $M$-ary hypothesis tests also show that by increasing the channel rates the performance of the tandem network significantly improves