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Theory and Practice of Hybrid Agents

Christoph Georg Jung; Klaus Fischer
DFKI, DFKI Research Reports (RR), Vol. 01-01, 2001.


Hybrid agents integrate different styles of reactive, deliberative, and cooperative problem solving in a modular fashion. They are the prime device of (Distributed) Artificial Intelligence and Cognitive Science for realising a broad spectrum of simultaneous functionalities in application domains such as Artificial Life, (Tele-)Robotics, Flexible Manufacturing, and Automated Transportation. In this report we propose a design methodology for hybrid agents which combines complementary approaches of Software Engineering and declarative Cog-nitive Robotics at five interconnected specification stages: Architecture, Computational Model, Theory, Inference, and Implementation. The design methodology is then applied to the reconstruction of the layered agent model InteRRaP (Integration of Reactivity and RAtional Planning). In-teRRaP, in spite of its practical success in the past, suffers from its originally architecture-centred and informal description. The result is an agent model, InteRRaP-R (the additional R stands for Resource-adapting), which maps its layered architecture onto the formally described interplay of concurrent processes whose runtime is scheduled by meta-control: The processes of a higher layer con-trol the processes of the subordinate layer by the allocation of (computational) resources. Processes are continuous computational activities that are realised as situated inference procedures which implement well-defined subsets of a com-mon logic of time and action. Three representative scenarios are chosen for an evaluation of InteRRaP-R: the Automated Loading Dock, the RoboCup Simulation League, and the ROTEX space robot. These case studies confirm the applicability of our slogan "Agent = Logic + Architecture" to the theory and practice of hybrid agents.