Education
Dynamic Teaching in Sequential Decision Making Environments
Walsh, Thomas J., Goschin, Sergiu
We describe theoretical bounds and a practical algorithm for teaching a model by demonstration in a sequential decision making environment. Unlike previous efforts that have optimized learners that watch a teacher demonstrate a static policy, we focus on the teacher as a decision maker who can dynamically choose different policies to teach different parts of the environment. We develop several teaching frameworks based on previously defined supervised protocols, such as Teaching Dimension, extending them to handle noise and sequences of inputs encountered in an MDP.We provide theoretical bounds on the learnability of several important model classes in this setting and suggest a practical algorithm for dynamic teaching.
An Improved Admissible Heuristic for Learning Optimal Bayesian Networks
Yuan, Changhe, Malone, Brandon
Recently two search algorithms, A* and breadth-first branch and bound (BFBnB), were developed based on a simple admissible heuristic for learning Bayesian network structures that optimize a scoring function. The heuristic represents a relaxation of the learning problem such that each variable chooses optimal parents independently. As a result, the heuristic may contain many directed cycles and result in a loose bound. This paper introduces an improved admissible heuristic that tries to avoid directed cycles within small groups of variables. A sparse representation is also introduced to store only the unique optimal parent choices. Empirical results show that the new techniques significantly improved the efficiency and scalability of A* and BFBnB on most of datasets tested in this paper.
Local Structure Discovery in Bayesian Networks
Niinimaki, Teppo, Parviainen, Pekka
Learning a Bayesian network structure from data is an NP-hard problem and thus exact algorithms are feasible only for small data sets. Therefore, network structures for larger networks are usually learned with various heuristics. Another approach to scaling up the structure learning is local learning. In local learning, the modeler has one or more target variables that are of special interest; he wants to learn the structure near the target variables and is not interested in the rest of the variables. In this paper, we present a score-based local learning algorithm called SLL. We conjecture that our algorithm is theoretically sound in the sense that it is optimal in the limit of large sample size. Empirical results suggest that SLL is competitive when compared to the constraint-based HITON algorithm. We also study the prospects of constructing the network structure for the whole node set based on local results by presenting two algorithms and comparing them to several heuristics.
An Overview of Recent Application Trends at the AAMAS Conference: Security, Sustainability and Safety
Jain, Manish (University of Southern California) | An, Bo (University of Southern California) | Tambe, Milind (University of Southern California)
A key feature of the AAMAS conference is its emphasis on ties to real-world applications. The focus of this article is to provide a broad overview of application-focused papers published at the AAMAS 2010 and 2011 conferences. More specifically, recent applications at AAMAS could be broadly categorized as belonging to research areas of security, sustainability and safety. We outline the domains of applications, key research thrusts underlying each such application area, and emerging trends.
AAAI News
Hamilton, Carol M. (Association for the Advancement of Artificial Intelligence)
He has been chairman/president the MIT Artificial Intelligence Lab. Board of Trustees, as well as treasurer 100 Americans most likely to shape Manuela Veloso, incoming AAAI President, of SSAISB and ECCAI. He is presently the next century; TIME Digital selected and Eric Horvitz, AAAI Past editor-in-chief of the AAAI Press, Spatial her as a member of the Cyber-Elite; President and Awards Committee Cognition and Computation, and the World Economic Forum honored Chair, presented the AAAI Awards in the Artificial Intelligence Journal. He was her with the title Global Leader for Tomorrow; August at AAAI-12 in Toronto. She holds bachelor's and or 1-650-328-3123.)
Multiagent Learning: Basics, Challenges, and Prospects
Tuyls, Karl (Maastricht University) | Weiss, Gerhard (Maastricht University)
Multiagent systems (MAS) are widely accepted as an important method for solving problems of a distributed nature. A key to the success of MAS is efficient and effective multiagent learning (MAL). The past twenty-five years have seen a great interest and tremendous progress in the field of MAL. This article introduces and overviews this field by presenting its fundamentals, sketching its historical development and describing some key algorithms for MAL. Moreover, main challenges that the field is facing today are indentified.
A General Methodology for the Determination of 2D Bodies Elastic Deformation Invariants. Application to the Automatic Identification of Parasites
Arabadjis, Dimitris, Rousopoulos, Panayiotis, Papaodysseus, Constantin, Panagopoulos, Michalis, Loumou, Panayiota, Theodoropoulos, Georgios
A novel methodology is introduced here that exploits 2D images of arbitrary elastic body deformation instances, so as to quantify mechano-elastic characteristics that are deformation invariant. Determination of such characteristics allows for developing methods offering an image of the undeformed body. General assumptions about the mechano-elastic properties of the bodies are stated, which lead to two different approaches for obtaining bodies' deformation invariants. One was developed to spot deformed body's neutral line and its cross sections, while the other solves deformation PDEs by performing a set of equivalent image operations on the deformed body images. Both these processes may furnish a body undeformed version from its deformed image. This was confirmed by obtaining the undeformed shape of deformed parasites, cells (protozoa), fibers and human lips. In addition, the method has been applied to the important problem of parasite automatic classification from their microscopic images. To achieve this, we first apply the previous method to straighten the highly deformed parasites and then we apply a dedicated curve classification method to the straightened parasite contours. It is demonstrated that essentially different deformations of the same parasite give rise to practically the same undeformed shape, thus confirming the consistency of the introduced methodology. Finally, the developed pattern recognition method classifies the unwrapped parasites into 6 families, with an accuracy rate of 97.6 %.
TEAM-IT : Location-Based Gaming in Real and Virtual Environments
Frazier, Spencer John (University of Southern California) | Newnan, Alex (University of Southern California) | Maheswaran, Rajiv (University of Southern California) | Chang, Yu-Han (University of Southern California) | Frangoudes, Fotos (University of Southern California)
Location-based games are an emerging paradigm fortraining, simulation, entertainment, health and many other domains. In this paper, we consider the role of artificialagents in such games. We also examine how human teams perform when given the same game, playedin both a real environment with mobile devices and alsoin a virtual environment that replicates the real environment.We perform the first direct comparison of real andvirtual instantiations of the same location-based game.We show the similarities and differences in game playand then investigate how adding an advice-giving agentchanges the experience.
Artificial Intelligence and Personalization Opportunities for Serious Games
Brisson, Antรณnio (INESC-ID and Instituto Superior Tรฉcnico) | Pereira, Gonรงalo (INESC-ID and Instituto Superior Tรฉcnico) | Prada, Rui (INESC-ID and Instituto Superior Tรฉcnico) | Paiva, Ana (INESC-ID and Instituto Superior Tรฉcnico) | Louchart, Sandy (Harriot-Watt University) | Suttie, Neil (Harriot-Watt University) | Lim, Theo (Harriot-Watt University) | Lopes, Ricardo Abreu (T U Delft) | Bidarra, Rafael (Politecnico di Milano) | Bellotti, Francesco (RWTH-Aachen) | Kravcik, Milos (Syntef) | Oliveira, Manuel Fradinho
Artificial Intelligence (AI) and Personalization are both essential - How do we relate content (the factual knowledge aspects of all games, be they serious or entertainment contained, game mechanics) and context (experiences based. In this research the role of AI and Personalization is and activities) to pedagogical goals towards supporting however focused upon the context of Serious Games (SG) in pedagogically-driven design and development of SGs? particular. A concerted research direction is necessary in this From these two high-level questions we derived a more area so as to establish future benchmarks and metrics for the pragmatic approach to AI and Personalization based on: In effective use of AI and Personalization in serious games design what ways can personalization improve learning and adapt and will benefit relevant research communities in providing best to learner requirements?