Essex Wizards ’99 Team Description.pdf

Essex Wizards’99 Team Description H. Hu, K. Kostiadis, M. Hunter, M. Seabrook Department of Computer Science, University of Essex Wivenhoe Park, Colchester CO4 3SQ, United Kingdom Email: {hhu,kkosti,mchunt,seabmn}@essex.ac.uk Abstract: This paper describes the Essex Wizards team participated in the RoboCup99 simulator league. It is mainly concentrated on a multi-threaded implementation of simulated soccer agents to achieve real-time performance. Simulated robot agents work at three distinct phases: sensing, thinking and acting. POSIX threads are adopted to implement them concurrently. The issues of decision-making and co-operation are also addressed. 1. Introduction In the RoboCup simulator environment, the response time of a soccer agent becomes significantly important since the soccer server operates with 100ms cycles for executing actions and 150ms cycles for providing sensory data [12]. Moreover, auditory sensory data can be received at random intervals. It is vital that each agent has bounded response times. If an action is not generated within 100ms, then the agent will stay idle for that cycle and enemy agents that did act might gain an advantage. On the other hand, if more than one action is generated per cycle, the server will only execute one of them chosen randomly. An additional constraint is that Unix is not a “true” real-time system and hence real-time performance and response times can only be guaranteed up to a certain resolution [13]. A more detailed description of real-time systems can be found in [2,11]. In addition to the responsiveness, the ability to cope with changes in the agent‘s environmen