§16§This volume contains the papers presented at AI 2007: The 20th Australian Joint Conference on Arti?cial Intelligence held during December 2-6, 2007 on the Gold Coast, Queensland, Australia. AI 2007 attracted 194 submissions (full papers) from 34 countries. The review process was held in two stages. In the ?rst stage, the submissions were assessed for their relevance and readability by the Senior Program Committee members. Those submissions that passed the ?rst stage were then reviewed by at least three Program Committee members and independent reviewers. After extensive disc- sions, the Committee decided to accept 60 regular papers (acceptance rate of 31%) and 44 short papers (acceptance rate of 22.7%). Two regular papers and four short papers were subsequently withdrawn and are not included in the proceedings. AI 2007 featured invited talks from four internationally distinguished - searchers, namely, Patrick Doherty, Norman Foo, Richard Hartley and Robert Hecht-Nielsen. They shar §16§ed their insights and work with us and their contri- tions to AI 2007 were greatly appreciated. AI 2007 also featured workshops on integrating AI and data-mining, semantic biomedicine and ontology. The short papers were presented in an interactive poster session and contributed to a st- ulating conference. It was a great pleasure for us to serve as the Program Co-chairs of AI 2007. §04§Invited Talks.- Machine Learning.- Neural Networks.- Evolutionary Computing.- Constraint Satisfaction.- Satisfiability.- Automated Reasoning.- Knowledge Discovery.- Robotics.- Social Intelligence.- Ontologies and Semantic Web.- Natural Language Systems.- Knowledge Representation.- Expert Systems.- Applications of AI.- Short Papers. §04§r Ontology for Event Classifications and Relations.- A Within-Frame Ontological Extension on FrameNet: Application in Predicate Chain Analysis and Question Answering.- Using Clustering for Web Information Extraction.- Natural Language Systems.- A Decision Tree Approach to Sentence Chunking.- The Semantic Representation of Temporal Expressions in Text.- Effectiveness of Methods for Syntactic and Semantic Recognition of Numeral Strings: Tradeoffs Between Number of Features and Length of Word N-Grams.- Using Automated Error Profiling of Texts for Improved Selection of Correction Candidates for Garbled Tokens.- Hypothesis Generation and Maintenance in the Interpretation of Spoken Utterances.- Knowledge Representation.- Temporal Extensions to Defeasible Logic.- Characterising Deadlines in Temporal Modal Defeasible Logic.- Dialogue Games in Defeasible Logic.- Implementing Iterated Belief Change Via Prime Implicates.- Expert Systems.- Applying MCRDR to a Multidisciplinary Domain.- Contin §04§uity of Fuzzy Approximate Reasoning and Its Application to Optimization.- Applications of AI.- Tomographic Reconstruction of Images from Noisy Projections - A Preliminary Study.- Automated Intelligent Abundance Analysis of Scallop Survey Video Footage.- Multiple Classifier Object Detection with Confidence Measures.- Agent-Based Distributed Energy Management.- Adaptation Knowledge from the Case Base.- Building Classification Models from Microarray Data with Tree-Based Classification Algorithms.- MAUSA: Using Simulated Annealing for Guide Tree Construction in Multiple Sequence Alignment.- Short Papers.- A System for Modal and Deontic Defeasible Reasoning.- Time-Reversal in Conway's Life as SAT.- A Knowledge-Based Approach to Named Entity Disambiguation in News Articles.- Real-Time Scheduling for Non-crossing Stacking Cranes in an Automated Container Terminal.- The Detrimentality of Crossover.- Automatic Sapstain Detection in Processed Timber.- Structure-Sensitive Learning of Text Ty
