Name : Michael Johnson

Telephone : +353-61-202715

Fax : +353-61-202572

E-mail : michael dot johnson (at) ul dot ie

Desk Location : F2-125


Areas of Interest: Swarm Robotics, Dynamic Control, Robotics, Mobile Ad-hoc Wireless Networking

Current Research Area:

Swarm Robotics: - Swarm robotics is a new approach to the coordination of multirobot systems which consist of large numbers of mostly simple physical robots. Research at present is to study the design of robots, their physical body and their controlling behaviors. Relative simple individual rules can produce a large set of complex swarm behavior. Key to the swarm behaviour is the communication between the members of the group that build a system of constant feedback. The swarm behavior involves constant change of individuals in cooperation with others, as well as the behavior of the whole group.
Pursuit-Evasion Games: - The Pursuit-Evasion Game (PEG) is an area of research deriving from the fields of mathematics and computer science. The multi-pursuer, multi-evader scenario is a classical problem in the field of Distributed Artifical Intelligence (DAI), where cooperative behaviour between the robots is required to capture the evader(s). In it’s simplest possible implementation, the problem consists of 2 groups, pursuers and evaders. The aim here is for the pursuer group to track down the evaders in the given environment. The original problem was first proposed by R.P. Issaacs in 1965. Using this formulation, the problem was modelled geometrically. In 1976, Parsons introduced an alternative implementation whereby group movement was constrained to a discrete graph. All subsequent research in this field has typically focused on either the continuous pursuit-evasion problem proposed by Isaacs or the discrete pursuit-evasion problem derived by Parsons.
Mobile Ad-Hoc Wireless Networks: - A wireless ad hoc network is a decentralized wireless network. The network is ad hoc because each node is willing to forward data for other nodes, and so the determination of which nodes forward data is made dynamically based on the network connectivity. This is in contrast to wired networks in which routers perform the task of routing. The decentralized nature of wireless ad hoc networks makes them suitable for a variety of applications where conventional networks are not suitable. In addition, minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters or military conflicts.
Dynamic Power Control: - Power control, broadly speaking, is the intelligent selection of transmit power in a communication system to achieve good performance within the system. The notion of "good performance" can depend on context and may include optimizing metrics such as link data rate, network capacity, geographic coverage and range, and life of the network and network devices. In general, higher transmission power yields better throughput rates on the network, but at the price of shorter battery life for the nodes involved. Power Control algorithms seek to optimise this trade-off by ensuring the minimum throughput rate for the desired Quality-of-Service is maintained for the longest battery life possible.

Thesis/Project Objectives:

The research will address the problem of cooperative learning for a team of independent robots attempting to satisfy a common performance objective. The focus of the work will be on characterising the effect that a low power ad hoc network will have on the performance of a collective task. In particular the project will investigate how wireless technology can be used with confidence in “Intruder Alert”, “Security Risk”, “Hazardous Mapping” type applications. An example scenario would be an event requiring robot intervention that may occur aperiodically, how can energy consumption be optimised without compromising safety in such an environment?
Current research is in adapting swarm robotics to the arena of pursuit-evasion games. Using LEGO Mindstorm robots with appropriate networking capabilities, a single-evader-multiple-pursuer scenario will be investigated, wherein a number of different pursuit handoff algorithms will be tested. It is hoped to derive a cumulative algorithm which improves on the current system from this research.

Other Interest : Travelling, TaeKwonDo, Photography, Scuba Diving, Astronomy... to name but a few :D

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