A Mobile Agent Cloning Controller for Servicing Networked Robots
W.Wilfred Godfrey
1,a
and Shivashankar B. Nair
1,b
1
Indian Institute of Technology Guwahati, India
a
w.godfrey@iitg.ernet.in,
b
sbnair@iitg.ernet.in
Abstract. In this paper we describe how mobile agents that form service providers in a robotic network
stigmergically sense the available bandwidth and control their respective cloning rates so as to reduce service
times. Apart from a life-time, these agents also have a Cloning Resource which is charged by rewards gained
as and when they service the robots. This novel concept of resource embeds an adaptive demand based
cloning behavior. The results portrayed in this paper clearly show that the use of such a resource inhibits
excessive cloning which otherwise could degrade the efficiency and speed of the service.
Keywords: Mobile Agents, Networked Robots, Cloning, Population Control.
1. Introduction
Mobile agents are programs which carry their execution state along with data from one node to another
within a network. Based on the application, they can be programmed to perform a variety of tasks. In
addition to being mobile and autonomous, these agents also have the ability to clone. Creating multiple
clones can, in many scenarios, improve robustness, fault tolerance and efficiency [1]. Since clones possess
the same capabilities as their originals, they allow for a parallel and hence faster dissemination of the
information contained within them. Unregulated cloning can however lead to the creation of a large number
of such agents, which in turn can consume the network bandwidth and other related resources resulting in a
rapid degradation in performance. It is thus essential to exercise an appropriate and near optimal control on
their population lest such a clonal expansion cause the over-populated network to come to a stand-still. In
addition, for certain dynamic environments, it may also be essential to increase their population based on
demand [2]. In real systems, a centralized mechanism will naturally consume a considerable part of the
bandwidth in periodically communicating with the agents (or nodes) within the network, thus degrading
performance of the system. Though decentralized or distributed mechanisms [3, 4] have been suggested, they
are aimed at a homogenous set of agents and are not on-demand based mechanisms. Decentralized control of
a population of heterogeneous agents still remains a challenging task. In this paper, we describe a novel
decentralized mechanism to control selective agent populations to cater to a distributed networked robotic
application. Armed with a resource for cloning, agents within this network, use stigmergic [5] means to
approximate the agent population and autonomously decide whether or not to clone.
2. Networked Robots: Application Scenario
Godfrey and Nair [2] have proposed an architecture for networked multi-mobile-robot systems which
uses mobile agents to service the robots. They have also suggested the use of a Pheromone- Conscientious
(PherCon) migration strategy [6] for mobile agents residing in a robotic node. Each robotic node periodically
senses and updates its list of neighbours. In addition, the robotic node also contains a platform that can host
mobile agents. Mobile agents carrying services populate the network. A service could be some useful
information (such as source code, rules, etc.) required by a robotic node. The network allows users to tether
robots without the need to embed, a priori, programs for all tasks they can perform. When a robot is issued a
2011 International Conference on Future Information Technology
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