This book is a collection of 45 accepted papers originally submitted for the 12th International Conference of the Catalan Association for Artificial Intelligence (ACIA). It also includes a brief summary of two papers from invited speakers. The Catalan Association for Artificial Intelligence was founded in 1994 with the aim of fostering cooperation among researchers from the Catalan-speaking AI research community. Collaboration between ACIA members and the wider international AI community has also been well-established now for many years. The papers in these proceedings reflect this collaboration and include contributions not only from the Catalan-speaking regions of Spain, but also from France and Italy, and from as far afield as Mexico and Australia. Of all the computer sciences, AI is the one most intertwined with all sorts of disciplines dealt with in the human experience, often employing lessons learnt in one discipline to implement a task in another. The papers in this volume reflect the rich diversity inside AI, covering areas such as logics, natural language, machine learning, computer vision, robotics and multi-agent systems.

Invited Talks
Scientific and Technological Challenges of Musical Interest/ X. Serra
How Great Apes Think/ J. Call

Robotics, Vision and Perception
Evaluation of the SIFT Object Recognition Method in Mobile Robots/ A. Ramisa, S. Vasudevan, D. Aldavert, R. Toledo and R. Lopez De Mantaras
Terrain Classification for Outdoor Mobile Robots Using PCA/ D. Caballero Parga, A. Figueras, S. Esteva and R. Hesse
Generic Object Recognition in Urban Image Databases/ X. Baró, S. Escalera, P. Radeva and J. Vitrià
Text Detection in Urban Scenes/ S. Escalera, X. Baró, J. Vitrià and P. Radeva
Measuring Interest of Human Dyadic Interactions/ S. Escalera, O. Pujol, P. Radeva and J. Vitrià
Appearance-Based SLAM for Mobile Robots/ B. Bacca, J. Salvi and X. Cufí
Patch Growing: Object Segmentation Using Spatial Coherence of Local Patches/ M. Masias, A. Torrent, X. Lladó and J. Freixenet
A First Approach to Activity Recognition Using Topic Models/ P. Casale, O. Pujol, P. Radeva and J. Vitrià
Coordination Motion-Tasks Using Actual Robot Dynamics/ D. Pardo, S. Del Moral and C. Angulo
Shout and Act/ J. Lluis De La Rosa, A. Trias, A. Martorano, E. Colomeda, D. Huerva and E. Del Acebo

Machine Learning
The Paradox of the Mitigant Trajectories: Consequences on Interpretation of Dynamical Patterns/ G. Rodríguez-Silva and K. Gibert
Multi-Scale Multi-Resolution Stacked Sequential Learning/ E. Puertas, C. Gatta and O. Pujol
Using a Simulated Annealing to Enhance Learning in Adjustment Processes/ A. Samà, F.J. Ruiz, N. Agell and C. Angulo
Collaborative Agent-Based Learning for Brain Tumour Diagnosis/ X. Rafael-Palou, M. Rovatsos, M. Mier-Perez and M. Lluch-Ariet
Classification Using Intelligent Approaches. An Example in Social Assistance/ M. Miró-Julià, G. Fiol-Roig and D. Vaquer-Ferrer
On In-Vitro and In-Vivo IVUS Data Fusion/ F. Ciompi, O. Pujol, O. Rodríguez-Leor, A. Serrano-Vida, J. Mauri and P. Radeva
Dynamic Adaptive Case Library for Continuous Domains/ F. Orduña Cabrera and M. Sànchez-Marrè

Multi-Agents Systems
A Formalization of Trust Alignment/ A. Koster, J. Sabater-Mir and M. Schorlemmer
Contract Formation Through Preemptive Normative Conflict Resolution/ W.W. Vasconcelos and T.J. Norman
Interaction, Observance or Both? Study of the Effects on Convention Emergence/ D. Villatoro, J. Sabater-Mir and S. Sen
2-LAMA Architecture vs. BitTorrent Protocol in a Peer-to-Peer Scenario/ J. Campos, M. Lopez-Sanchez, M. Esteva, A. Novo and J. Morales
J-MADeM, an Open-Source Library for Social Decision-Making/ F. Grimaldo, M. Lozano and F. Barber
Anytime Reasoning Mechanism for Conversational Agents/ M. Morveli-Espinoza and J. Puyol-Gruart
Coherence as an Inclusive Notion of Rationality/ S. Joseph, M. Schorlemmer and C. Sierra
Towards a Secure, Group-Oriented and Efficient Framework for Intelligent Virtual Environments/ J.M. Alberola, J.M. Such, A. Barella and A. Garcia-Fornes
Customization of an Agent-Based Medical System/ M. Batet, S. Martínez, A. Valls and K. Gibert
mWater: A Sandbox for Agreement Technologies/ A. Garrido, A. Giret and P. Noriega

Logics, Constraint Satisfaction and Qualitative Reasoning
Secure and Optimal Base Contraction in Graded Lukasiewicz Logics/ P. Pardo, P. Dellunde and L. Godo
A Cryptographic Solution for Private Distributed Simple Meeting Scheduling/ J. Herranz, S. Matwin, P. Meseguer and J. Nin
On Solving MaxSAT Through SAT/ C. Ansótegui, M. Luisa Bonet and J. Levy
AC3-OP: An Arc-Consistency Algorithm for Arithmetic Constraints/ M. Arangu, M.A. Salido and F. Barber
Stability of Solutions in Constraint Satisfaction Problems/ L. Climent, M.A. Salido and F. Barber
A Boost in Exchange Rate Forecasting: Qualitative Variables, Technical Indicators and Parameters Selection/ J. Antonio Sanabria, G. Sánchez and N. Agell
A Similarity Calculus for Comparing Qualitative Shape Descriptions/ Z. Falomir, J. Almazán, J. Grande, L. Museros and M.T. Escrig

Natural Language
A New Lexical Chain Algorithm Used for Automatic Summarization/ E. Gonzàlez and M. Fuentes
Seeking Acronym Definitions: A Web-Based Approach/ D. Sánchez and D. Isern

AI Real-World Applications
Neuro-Fuzzy Approach for the Characterization of Building Materials/ A. Traore, S. Grieu, O. Faugeroux, B. Claudet and J.-L. Bodnar
Reward System for Completing FAQs/ A. Moreno, J. Lluis De La Rosa, B.K. Szymanski and J. Moisés Barcenas
Reasoning About Actions for the Management of Urban Wastewater Systems: Preliminary Report/ J.C. Nieves, M. Aulinas and U. Cortés
Human-Like Heuristics in Scrabble/ A. Gonzalez Romero, R. Alquezar, A. Ramirez, F. Gonzalez Acuña and I. Garcia Olmedo
Frequency Selection for the Diagnostic Characterization of Human Brain Tumours/ C. Arizmendi, A. Vellido and E. Romero
Fault Detection and Identification in a Fuel Cell System/ A. Escobet and À. Nebot
Approaches to Hospital Process Management/ M. Lopez-Sanchez, J. Campos and A. Musavi
REST Web Services in Collaborative Work Environments/ L. Oliva and L. Ceccaroni
A Formal Model of Competence-Based Assessment/ T. Alsinet, D. Barroso, R. Béjar and J. Planes