Instructional Material
Multi-Armed Bandits for Intelligent Tutoring Systems
Clement, Benjamin, Roy, Didier, Oudeyer, Pierre-Yves, Lopes, Manuel
We present an approach to Intelligent Tutoring Systems which adaptively personalizes sequences of learning activities to maximize skills acquired by students, taking into account the limited time and motivational resources. At a given point in time, the system proposes to the students the activity which makes them progress faster. We introduce two algorithms that rely on the empirical estimation of the learning progress, RiARiT that uses information about the difficulty of each exercise and ZPDES that uses much less knowledge about the problem. The system is based on the combination of three approaches. First, it leverages recent models of intrinsically motivated learning by transposing them to active teaching, relying on empirical estimation of learning progress provided by specific activities to particular students. Second, it uses state-of-the-art Multi-Arm Bandit (MAB) techniques to efficiently manage the exploration/exploitation challenge of this optimization process. Third, it leverages expert knowledge to constrain and bootstrap initial exploration of the MAB, while requiring only coarse guidance information of the expert and allowing the system to deal with didactic gaps in its knowledge. The system is evaluated in a scenario where 7-8 year old schoolchildren learn how to decompose numbers while manipulating money. Systematic experiments are presented with simulated students, followed by results of a user study across a population of 400 school children.
MLitB: Machine Learning in the Browser
Meeds, Edward, Hendriks, Remco, Faraby, Said Al, Bruntink, Magiel, Welling, Max
With few exceptions, the field of Machine Learning (ML) research has largely ignored the browser as a computational engine. Beyond an educational resource for ML, the browser has vast potential to not only improve the state-of-the-art in ML research, but also, inexpensively and on a massive scale, to bring sophisticated ML learning and prediction to the public at large. This paper introduces MLitB, a prototype ML framework written entirely in JavaScript, capable of performing large-scale distributed computing with heterogeneous classes of devices. The development of MLitB has been driven by several underlying objectives whose aim is to make ML learning and usage ubiquitous (by using ubiquitous compute devices), cheap and effortlessly distributed, and collaborative. This is achieved by allowing every internet capable device to run training algorithms and predictive models with no software installation and by saving models in universally readable formats. Our prototype library is capable of training deep neural networks with synchronized, distributed stochastic gradient descent. MLitB offers several important opportunities for novel ML research, including: development of distributed learning algorithms, advancement of web GPU algorithms, novel field and mobile applications, privacy preserving computing, and green grid-computing. MLitB is available as open source software.
Learning with Square Loss: Localization through Offset Rademacher Complexity
Liang, Tengyuan, Rakhlin, Alexander, Sridharan, Karthik
Determining the finite-sample behavior of risk in the problem of regression is arguably one of the most basic problems of Learning Theory and Statistics. This behavior can be studied in substantial generality with the tools of empirical process theory. When functions in a given convex class are uniformly bounded, one may verify the socalled "Bernstein condition." The condition--which relates the variance of the increments of the empirical process to their expectation--implies a certain localization phenomenon around the optimum and forms the basis of the analysis via local Rademacher complexities. The technique has been developed in [9, 8, 5, 2, 4], among others, based on Talagrand's celebrated concentration inequality for the supremum of an empirical process. In a recent pathbreaking paper, [14] showed that a large part of this heavy machinery is not necessary for obtaining tight upper bounds on excess loss, even--and especially--if functions are unbounded. Mendelson observed that only one-sided control of the tail is required in the deviation inequality, and, thankfully, it is the tail that can be controlled under very mild assumptions. In a parallel line of work, the search within the online learning setting for an analogue of "localization" has led to a notion of an "offset" Rademacher process [17], yielding--in a rather clean manner--optimal rates for minimax regret in online supervised learning. It was also shown that the supremum of the offset process is a lower bound on the minimax value, thus establishing its intrinsic nature.
Training generative neural networks via Maximum Mean Discrepancy optimization
Dziugaite, Gintare Karolina, Roy, Daniel M., Ghahramani, Zoubin
We consider training a deep neural network to generate samples from an unknown distribution given i.i.d. data. We frame learning as an optimization minimizing a two-sample test statistic---informally speaking, a good generator network produces samples that cause a two-sample test to fail to reject the null hypothesis. As our two-sample test statistic, we use an unbiased estimate of the maximum mean discrepancy, which is the centerpiece of the nonparametric kernel two-sample test proposed by Gretton et al. (2012). We compare to the adversarial nets framework introduced by Goodfellow et al. (2014), in which learning is a two-player game between a generator network and an adversarial discriminator network, both trained to outwit the other. From this perspective, the MMD statistic plays the role of the discriminator. In addition to empirical comparisons, we prove bounds on the generalization error incurred by optimizing the empirical MMD.
Predicting Speech Acts in MOOC Forum Posts
Arguello, Jaime (University of North Carolina at Chapel Hill) | Shaffer, Kyle (University of North Carolina at Chapel Hill)
Students in a Massive Open Online Course (MOOC) interact with each other and the course staff through online discussion forums. While discussion forums play a central role in MOOCs, they also pose a challenge for instructors. The large number of student posts makes it difficult for an instructor to know where to intervene to answer questions, resolve issues, and provide feedback. In this work, we focus on automatically predicting speech acts in MOOC forum posts. Our speech act categories describe the purpose or function of the post in the ongoing discussion. Specifically, we address three main research questions. First, we investigate whether crowdsourced workers can reliably label MOOC forum posts using our speech act definitions. Second, we investigate whether our speech acts can help predict instructor interventions and assignment completion and performance. Finally, we investigate which types of features (derived from the post content, author, and surrounding context) are most effective for predicting our different speech act categories.
Reports of the Workshops Held at the Tenth AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment
Barnes, Tiffany (North Carolina State University) | Bown, Oliver (University of Sydney) | Buro, Michael (University of Alberta) | Cook, Michael (Goldsmiths College, University of London) | Eigenfeldt, Arne (Simon Fraser University) | Muñoz-Avila, Héctor (Lehigh University) | Ontañón, Santiago (Drexel University) | Pasquier, Philippe (Simon Fraser University) | Tomuro, Noriko (DePaul University) | Young, R. Michael (North Carolina State University) | Zook, Alexander (Georgia Institute of Technology)
The AIIDE-14 Workshop program was held Friday and Saturday, October 3–4, 2014 at North Carolina State University in Raleigh, North Carolina. The workshop program included five workshops covering a wide range of topics. The titles of the workshops held Friday were Games and Natural Language Processing, and Artificial Intelligence in Adversarial Real-Time Games. The titles of the workshops held Saturday were Diversity in Games Research, Experimental Artificial Intelligence in Games, and Musical Metacreation. This article presents short summaries of those events.
Reports of the AAAI 2014 Conference Workshops
Albrecht, Stefano V. (University of Edinburgh) | Barreto, André M. S. (Brazilian National Laboratory for Scientific Computing) | Braziunas, Darius (Kobo Inc.) | Buckeridge, David L. (McGill University) | Cuayáhuitl, Heriberto (Heriot-Watt University) | Dethlefs, Nina (Heriot-Watt University) | Endres, Markus (University of Augsburg) | Farahmand, Amir-massoud (Carnegie Mellon University) | Fox, Mark (University of Toronto) | Frommberger, Lutz (University of Bremen) | Ganzfried, Sam (Carnegie Mellon University) | Gil, Yolanda (University of Southern California) | Guillet, Sébastien (Université du Québec à Chicoutimi) | Hunter, Lawrence E. (University of Colorado School of Medicine) | Jhala, Arnav (University of California Santa Cruz) | Kersting, Kristian (Technical University of Dortmund) | Konidaris, George (Massachusetts Institute of Technology) | Lecue, Freddy (IBM Research) | McIlraith, Sheila (University of Toronto) | Natarajan, Sriraam (Indiana University) | Noorian, Zeinab (University of Saskatchewan) | Poole, David (University of British Columbia) | Ronfard, Rémi (University of Grenoble) | Saffiotti, Alessandro (Orebro University) | Shaban-Nejad, Arash (McGill University) | Srivastava, Biplav (IBM Research) | Tesauro, Gerald (IBM Research) | Uceda-Sosa, Rosario (IBM Research) | Broeck, Guy Van den (Katholieke Universiteit Leuven) | Otterlo, Martijn van (Radboud University Nijmegen) | Wallace, Byron C. (University of Texas) | Weng, Paul (Pierre and Marie Curie University) | Wiens, Jenna (University of Michigan) | Zhang, Jie (Nanyang Technological University)
The AAAI-14 Workshop program was held Sunday and Monday, July 27–28, 2012, at the Québec City Convention Centre in Québec, Canada. Canada. The AAAI-14 workshop program included fifteen workshops covering a wide range of topics in artificial intelligence. The titles of the workshops were AI and Robotics; Artificial Intelligence Applied to Assistive Technologies and Smart Environments; Cognitive Computing for Augmented Human Intelligence; Computer Poker and Imperfect Information; Discovery Informatics; Incentives and Trust in Electronic Communities; Intelligent Cinematography and Editing; Machine Learning for Interactive Systems: Bridging the Gap between Perception, Action and Communication; Modern Artificial Intelligence for Health Analytics; Multiagent Interaction without Prior Coordination; Multidisciplinary Workshop on Advances in Preference Handling; Semantic Cities — Beyond Open Data to Models, Standards and Reasoning; Sequential Decision Making with Big Data; Statistical Relational AI; and The World Wide Web and Public Health Intelligence. This article presents short summaries of those events.
Probabilistic Graphical Models for Boosting Cardinal and Ordinal Peer Grading in MOOCs
Mi, Fei (Hong Kong University of Science and Technology) | Yeung, Dit-Yan (Pong Kong University of Science and Technology)
With the enormous scale of massive open online courses (MOOCs), peer grading is vital for addressing the assessment challenge for open-ended assignments or exams while at the same time providing students with an effective learning experience through involvement in the grading process. Most existing MOOC platforms use simple schemes for aggregating peer grades, e.g., taking the median or mean. To enhance these schemes, some recent research attempts have developed machine learning methods under either the cardinal setting (for absolute judgment) or the ordinal setting (for relative judgment). In this paper, we seek to study both cardinal and ordinal aspects of peer grading within a common framework. First, we propose novel extensions to some existing probabilistic graphical models for cardi- nal peer grading. Not only do these extensions give su- perior performance in cardinal evaluation, but they also outperform conventional ordinal models in ordinal eval- uation. Next, we combine cardinal and ordinal models by augmenting ordinal models with cardinal predictions as prior. Such combination can achieve further performance boosts in both cardinal and ordinal evaluations, suggesting a new research direction to pursue for peer grading on MOOCs. Extensive experiments have been conducted using real peer grading data from a course called “Science, Technology, and Society in China I” offered by HKUST on the Coursera platform.
Cognitive Master Teacher
Krishnapuram, Raghu (IBM Research) | Lastras, Luis A (IBM Watson Group) | Nitta, Satya (IBM Research)
The “Cognitive Master Teacher” is a result of discussions with teachers, members of educational institutions, government bodies and other thought leaders in the United States who have helped us shape its the requirements. It is conceived as a cloud-based and mobile-accessible personal agent that is readily available for teachers to use at anytime and assist them with various issues related to day-to-day teaching activities as well as professional development.
Machine Teaching: An Inverse Problem to Machine Learning and an Approach Toward Optimal Education
Zhu, Xiaojin (University of Wisconsin-Madison)
I draw the reader's attention to machine teaching, the problem of finding an optimal training set given a machine learning algorithm and a target model. In addition to generating fascinating mathematical questions for computer scientists to ponder, machine teaching holds the promise of enhancing education and personnel training. The Socratic dialogue style aims to stimulate critical thinking.