DJ-MC: A Reinforcement-Learning Agent for Music Playlist Recommendation

In recent years, there has been growing focus on the study of automated recommender systems. Music recommendation systems serve as a prominent domain for such works, both from an academic and a commercial perspective. A fundamental aspect of music perception is that music is experienced in temporal context and in sequence. In this work we present DJ-MC, a novel reinforcement-learning framework for music recommendation that does not recommend songs individually but rather song sequences, or playlists, based on a model of preferences for both songs and song transitions. The model is learned online and is uniquely adapted for each listener. To reduce exploration time, DJ-MC exploits user feedback to initialize a model, which it subsequently updates by reinforcement. We evaluate our framework with human participants using both real song and playlist data. Our results indicate that DJ-MC's ability to recommend sequences of songs provides a significant improvement over more straightforward approaches, which do not take transitions into account.Comment: -Updated to the most recent and completed version (to be presented at AAMAS 2015) -Updated author list. in Autonomous Agents and Multiagent Systems (AAMAS) 2015, Istanbul, Turkey, May 201

Resolving Perception Based Problems in Human-Computer Dialogue

We investigate the effect of sensor errors on situated human­ computer dialogues. If a human user instructs a robot to perform a task in a spatial environment, errors in the robot\u27s sensor based perception of the environment may result in divergences between the user\u27s and the robot\u27s understanding of the environment. If the user and the robot communicate through a language based interface, these problems may result in complex misunderstand­ ings. In this work we investigate such situations. We set up a simulation based scenario in which a human user instructs a robot to perform a series of manipulation tasks, such as lifting, moving and re-arranging simple objects. We induce errors into the robot\u27s perception, such as misclassification of shapes and colours, and record and analyse the user\u27s attempts to resolve the problems. We evaluate a set of methods to alleviate the problems by allowing the operator to access the robot\u27s understanding of the scene. We investigate a uni-directional language based option, which is based on automatically generated scene descriptions, a visually based option, in which the system highlights objects and provides known properties, and a dialogue based assistance option. In this option the participant can a.sk simple questions about the robot\u27s perception of the scene. As a baseline condition we perform the experiment without introducing any errors. We evaluate and compare the success and problems in all four conditions. We identify and compare strategies the participants used in each condition. We find that the participants appreciate and use the information request options successfully. We find that that all options provide an improvement over the condition without information. We conclude that allowing the participants to access information about the robot\u27s perception state is an effective way to resolve problems in the dialogue

Concept Graph Learning from Educational Data

This paper addresses an open challenge in educational data mining, i.e., the problem of using observed prerequisite re-lations among courses to learn a directed universal con-cept graph, and using the induced graph to predict un-observed prerequisite relations among a broader range of courses. This is particularly useful to induce prerequisite relations among courses from different providers (universi-ties, MOOCs, etc.). We propose a new framework for in-ference within and across two graphs—at the course level and at the induced concept level—which we call Concept Graph Learning (CGL). In the training phase, our system projects the course-level links onto the concept space to in-duce directed concept links; in the testing phase, the concept links are used to predict (unobserved) prerequisite links for test-set courses within the same institution or across insti-tutions. The dual mappings enable our system to perform an interlingua-style transfer learning, e.g. treating the con-cept graph as the interlingua, and inducing prerequisite links in a transferable manner across different universities. Ex-periments on our newly collected data sets of courses fro