Stability of a class of multi-agent tracking systems with unstable subsystems

In this work, we pre-deploy a large number of smart agents to monitor an area of interest. This area could be divided into many Voronoi cells by using the knowledge of Voronoi diagram and every Voronoi site agent is responsible for monitoring and tracking the target in its cell. Then, a cooperative relay tracking strategy is proposed such that during the tracking process, when a target enters a new Voronoi cell, this event triggers the switching of both tracking agents and communication topology. This is significantly different from the traditional switching topologies. In addition, during the tracking process, the topology and tracking agents switch, which may lead the tracking system to be stable or unstable. The system switches either among consecutive stable subsystems and consecutive unstable subsystems or between stable and unstable subsystems. The objective of this paper is to design a tracking strategy guaranteeing overall successful tracking despite the existence of unstable subsystems. We also address extended discussions on the case where the dynamics of agents are subject to disturbances and the disturbance attenuation level is achieved. Finally, the proposed tracking strategy is verified by a set of simulations

Genetic diversity of kampung chicken (Gallus gallus domesticus) from selected areas in East Coast Peninsular Malaysia inferred from partial control region of mitochondrial DNA

After the 2014 Malaysia massive flood, genetic variation of the kampung chicken Gallus gallus domesticus in East Coast Peninsular Malaysia (ECPM) was investigated for a better understanding of their genetic diversity for its conservation. A total of fifty-nine samples were collected from three states; Kelantan, Terengganu and Pahang for mitochondrial DNA analysis. Partial mtDNA control regions were amplified, sequenced, and analyzed to determine the genetic variation among the states. Eleven haplotypes were detected among all the samples. Hap-1 was the most widespread haplotype among the three states and comprised of 45.8% of all samples. Genetic variation was the highest in Pahang (Pi = 0.01037, Hd = 0.8676), followed by Terengganu (Pi = 0.00938, Hd = 0.7316) and Kelantan (Pi = 0.00363, Hd = 0.5579). Low nucleotide diversity in Kelantan indicated the loss of genetic resources, which might be due to the population bottleneck phenomenon. Both the non-significant values of Tajima’s D and Fu’s FS in Pahang and Terengganu, suggested that they were at genetic equilibrium. Significant deviation from Tajima’s D neutrality test (P<0.05) in Kelantan indicated the possibility of population expansion, which might be a result of population recovery from the population bottleneck due to the massive flood in December 2014

A new approach to observer-based fault-tolerant controller design for Takagi-Sugeno fuzzy systems with state delay

This paper deals with the problem of active fault-tolerant control (FTC) for time-delay Takagi-Sugeno (T-S) fuzzy systems based on a fuzzy adaptive fault diagnosis observer (AFDO). A novel fuzzy fast adaptive fault estimation (FAFE) algorithm for T-S fuzzy models is proposed to enhance the performance of fault estimation, and sufficient conditions for the existence of the fault estimator are given in terms of linear matrix inequalities (LMIs). Using the obtained on-line fault estimation information, an observer-based fast active fault-tolerant controller is designed to compensate for the effect of faults by stabilizing the closed-loop system. Simulation results of a track trail system and a nonlinear numerical example are presented to illustrate the effectiveness of the proposed method.Ke Zhang, Bin Jiang, Peng Sh