Archive for September, 2007
Game AI for a Turn-based Strategy Game with Plan Adaptation and Ontology-based Retrieval
In this paper we present a novel approach for developing adaptive game AI by combining case based planning techniques and ontological knowledge from the game environment. The proposed architecture combines several components: a case-based hierarchical planner (Repair-SHOP), a bridge to connect and reason with Ontologies formalized in Description Logics (DLs) based languages (OntoBridge), a DLs reasoner (Pellet) and a framework to develop Case-Based Reasoning (CBR) systems (jCOLIBRI ). In our ongoing work we are applying this approach to a commercial Civilization clone turn-based strategy game (CTP2) where game AI is in charge of planning the strategies for automated players. Our goal is to demonstrate that ontology-based retrieval will result in the retrieval of strategies that are easier to adapt than those plans returned by other classical retrieval mechanisms traditionally used in case-based planning.
Transfer Learning of Hierarchical Task-Network Planning Methods in a Real-Time Strategy Game
We describe a new integrated and automated AI planning and learning architecture, called Learn2SHOP. Learn2SHOP departs significantly from the previous works on AI planning and learning in that its modular architecture integrates Hierarchical Task Network (HTN) planning, concept learning, and computer simulations. Using simulations during the planning and learning process enables the system to get information about the outcomes of the actions. We have implemented Learn2SHOP and tested it on a transfer-learning task. The objective of transfer learning is transferring knowledge and skills learned from a wide variety of previous situations to the current, and likely different, previously unencountered problems(s). The experiments with Learn2SHOP have demonstrated the advantages of integrating planning, learning, and simulation in a real-time strategy game engine.
Finite Element Simulation of Electromigration Cracking
Electromigration is one of the major problems that limits the reliability of high density microelectronics. Since microelectronic packages are expected to function reliably for long periods of time, it is crucial that numerical simulations be developed to aid in comprehensive package design. Electromigration is the transport of atoms in a conducting material due to momentum transfer from flowing electrons which leads to a failure in metal structures with high current densities. The presence of crack like defects in the conduction path accelerates the time to failure. The purpose of this paper is to describe a finite element formulation of the coupled stress-diffusion behavior that is observed in electromigration phenomenon. Specialized enriched crack tip elements, which simplify the fracture and reliability analyses, are used in this finite element formulation. A unique aspect of this work is the incorporation of defects (cracks) in the finite element models, which permits the direct calculation of relevant fracture parameters, like strain energy release rate, stress intensity factors and crack opening displacements.