Changing Communication Topology Research Articles

Finite-time semistability, Filippov systems, and consensus protocols for nonlinear dynamical networks with switching topologies

This paper focuses on semistability and finite-time semistability for discontinuous dynamical systems. Semistability is the property whereby the solutions of a dynamical system converge to Lyapunov stable equilibrium points determined by the system initial conditions. In this paper, we extend the theory of semistability to discontinuous autonomous dynamical systems. In particular, Lyapunov-based tests for strong and weak semistability as well as finite-time semistability for autonomous differential inclusions are established. Using these results we then develop a framework for designing semistable and finite-time semistable protocols for dynamical networks with switching topologies. Specifically, we present distributed nonlinear static and dynamic output feedback controller architectures for multiagent network consensus and rendezvous with dynamically changing communication topologies.

Traffic Organization by means of Vehicle-Sided Rule-Bases — A Cooperative Approach to Improved Traffic Quality and Traffic Safety

This contribution presents an approach to improve traffic quality by means of automation of vehicles that use car2car-communication. Methods for the formal derivation of decision-making while considering communication constraints and environmental boundary conditions are presented. Here Petrinets are used for behavioral modeling and formal derivation of control-structures, while at the implementation the decision-making is combined with consensus-algorithms which ensure formation convergence at latency and changing communication topology.

Unit Disk Graph Based Modelling of a Network of Mobile Agents

This contribution addresses the problem of communication topology changes induced by the movement of a set of mobile agents. The network is modeled as a unit disk graph (UDG) where each unit disk is centered in a node and where the communication topology is given by the instantaneous agents position. UDG allows for a compact representation of the communication topology as an intersection of unit disks. Fundamental properties of UDG are then used to characterize the feasible communication topologies. Under certain mobility assumptions, we show that all the transitions between the set of induced graphs are possible provided that the cardinality of the corresponding set of edges are different at most by one element.

Distributed linear estimation over sensor networks

We consider a network of sensors in which each node may collect noisy linear measurements of some unknown parameter. In this context, we study a distributed consensus diffusion scheme that relies only on bidirectional communication among neighbour nodes (nodes that can communicate and exchange data), and allows every node to compute an estimate of the unknown parameter that asymptotically converges to the true parameter. At each time iteration, a measurement update and a spatial diffusion phase are performed across the network, and a local least-squares estimate is computed at each node. The proposed scheme allows one to consider networks with dynamically changing communication topology, and it is robust to unreliable communication links and failures in measuring nodes. We show that under suitable hypotheses all the local estimates converge to the true parameter value.

Distributed Maximum Likelihood Estimation with Time-Varying Network Topology

We consider a sensor network in which each sensor may take at every time iteration a noisy linear measurement of some unknown parameter. In this context, we study a distributed consensus diffusion scheme that relies only on bidirectional communication among neighbor nodes (nodes that can communicate and exchange data), and allows every node to compute an estimate of the unknown parameter that asymptotically converges to the true parameter. At each time iteration, a measurement update and a spatial diffusion phase are performed across the network, and a local least-squares estimate is computed at each node. We show that the local estimates converge to the true parameter value, under suitable hypotheses. The proposed scheme works in networks with dynamically changing communication topology, and it is robust to unreliable communication links and widespread failures in measuring nodes.

Consensus Problem of Multi-Agent Systems with Non-linear Performance Functions

This paper addresses a discrete-time consensus problem with non-linear performance functions over dynamically changing communication topologies. Each agent has a performance value based on its internal information state and exchanges the performance value with other agents to achieve consensus. We derive sufficient conditions for a global consensus using algebraic graph theory.

Information consensus in multivehicle cooperative control

The purpose of this article is to provide a tutorial overview of information consensus in multivehicle cooperative control. Theoretical results regarding consensus-seeking under both time invariant and dynamically changing communication topologies are summarized. Several specific applications of consensus algorithms to multivehicle coordination are described

State consensus for multi-agent systems with switching topologies and time-varying delays

In this paper, we investigate state consensus problems for discrete-time multi-agent systems with changing communications topologies and bounded time-varying communication delays. The analysis in this paper is based on the properties of non-negative matrices. We first extend the model of networks of dynamic agents to the case with multiple time-delays and prove that if the communication topology, time-delays, and weighting factors are time-invariant, then the necessary and sufficient condition that the multi-agent system solves a consensus problem is that the communication topology, represented by a directed graph, has spanning trees. Then we allow for dynamically changing communication topologies and bounded time-varying communication delays, and present some sufficient conditions for state consensus of system. Finally, as a special case of our model, the problem of asynchronous information exchange is also discussed.

A discrete-time UML semantics for concurrency and communication in safety-critical applications

We define a subset krtUML of UML which is rich enough to express such modelling entities of UML, used in real-time applications, as active objects, dynamic object creation and destruction, dynamically changing communication topologies, combinations of synchronous and asynchronous communication, and shared memory usage through object attributes. We define a formal interleaving semantics for this kernel language by associating with each model M ∈ krtUML a symbolic transition system STS ( M ) . We briefly outline how to compile models of industrial systems making use of generalisation hierarchies, weak and strong aggregation, and hierarchical state-machines into krtUML. The main aim of the paper is to provide an executable semantics for krtUML suitable for the formal verification of temporal model properties with existing model-checking tools.