Europe
Strategic Behaviour When Allocating Indivisible Goods
We survey some recent research regarding strategic behaviour in resource allocation problems, focusing on the fair division of indivisible goods. We consider a number of computational questions like how a single strategic agent misreports their preferences to ensure a particular outcome, and how agents compute a Nash equilibrium when they all act strategically. We also identify a number of future directions like dealing with non-additive utilities, and partial or probabilistic information about the preferences of other agents.
From the Lab to the Classroom and Beyond: Extending a Game-Based Research Platform for Teaching AI to Diverse Audiences
Sintov, Nicole (University of Southern California) | Kar, Debarun (University of Southern California) | Nguyen, Thanh (University of Southern California) | Fang, Fei (University of Southern California) | Hoffman, Kevin (Aspire Public Schools) | Lyet, Arnaud (World Wildlife Fund) | Tambe, Milind (University of Southern California)
Recent years have seen increasing interest in AI from outside the AI community. This is partly due to applications based on AI that have been used in real-world domains, for example, the successful deployment of game theory-based decision aids in security domains. This paper describes our teaching approach for introducing the AI concepts underlying security games to diverse audiences. We adapted a game-based research platform that served as a testbed for recent research advances in computational game theory into a set of interactive role-playing games. We guided learners in playing these games as part of our teaching strategy, which also included didactic instruction and interactive exercises on broader AI topics. We describe our experience in applying this teaching approach to diverse audiences, including students of an urban public high school, university undergraduates, and security domain experts who protect wildlife. We evaluate our approach based on results from the games and participant surveys.
Using Domain Knowledge to Improve Monte-Carlo Tree Search Performance in Parameterized Poker Squares
Arrington, Robert (DePauw University) | Langley, Clay (DePauw University) | Bogaerts, Steven (DePauw University)
Poker Squares is a single-player card game played on a 5 x 5 grid, in which a player attempts to create as many high-scoring Poker hands as possible. As a stochastic single-player game with an extremely large state space, this game offers an interesting area of application for Monte-Carlo Tree Search (MCTS). This paper describes enhancements made to the MCTS algorithm to improve computer play, including pruning in the selection stage and a greedy simulation algorithm. These enhancements make extensive use of domain knowledge in the form of a state evaluation heuristic. Experimental results demonstrate both the general efficacy of these enhancements and their ideal parameter settings.
Affective Personalization of a Social Robot Tutor for Childrenโs Second Language Skills
Gordon, Goren (Tel Aviv-University) | Spaulding, Samuel (Massachusetts Institute of Technology) | Westlund, Jacqueline Kory (Massachusetts Institute of Technology) | Lee, Jin Joo (Massachusetts Institute of Technology) | Plummer, Luke (Massachusetts Institute of Technology) | Martinez, Marayna (Massachusetts Institute of Technology) | Das, Madhurima (Massachusetts Institute of Technology) | Breazeal, Cynthia (Massachusetts Institute of Technology)
Though substantial research has been dedicated towards using technology to improve education, no current methods are as effective as one-on-one tutoring. A critical, though relatively understudied, aspect of effective tutoring is modulating the student's affective state throughout the tutoring session in order to maximize long-term learning gains. We developed an integrated experimental paradigm in which children play a second-language learning game on a tablet, in collaboration with a fully autonomous social robotic learning companion. As part of the system, we measured children's valence and engagement via an automatic facial expression analysis system. These signals were combined into a reward signal that fed into the robot's affective reinforcement learning algorithm. Over several sessions, the robot played the game and personalized its motivational strategies (using verbal and non-verbal actions) to each student. We evaluated this system with 34 children in preschool classrooms for a duration of two months. We saw that (1) children learned new words from the repeated tutoring sessions, (2) the affective policy personalized to students over the duration of the study, and (3) students who interacted with a robot that personalized its affective feedback strategy showed a significant increase in valence, as compared to students who interacted with a non-personalizing robot. This integrated system of tablet-based educational content, affective sensing, affective policy learning, and an autonomous social robot holds great promise for a more comprehensive approach to personalized tutoring.
Optimizing Resilience in Large Scale Networks
Wu, Xiaojian (University of Massachusetts Amherst) | Sheldon, Daniel (University of Massachusetts Amherst and Mount Holyoke College) | Zilberstein, Shlomo (University of Massachusetts Amherst)
We propose a decision making framework to optimize the resilience of road networks to natural disasters such as floods. Our model generalizes an existing one for this problem by allowing roads with a broad class of stochastic delay models. We then present a fast algorithm based on the sample average approximation (SAA) method and network design techniques to solve this problem approximately. On a small existing benchmark, our algorithm produces near-optimal solutions and the SAA method converges quickly with a small number of samples. We then apply our algorithm to a large real-world problem to optimize the resilience of a road network to failures of stream crossing structures to minimize travel times of emergency medical service vehicles. On medium-sized networks, our algorithm obtains solutions of comparable quality to a greedy baseline method but is 30โ60 times faster. Our algorithm is the only existing algorithm that can scale to the full network, which has many thousands of edges.
Efficient Spatio-Temporal Tactile Object Recognition with Randomized Tiling Convolutional Networks in a Hierarchical Fusion Strategy
Cao, Lele (Tsinghua University and The University of Melbourne) | Kotagiri, Ramamohanarao (The University of Melbourne) | Sun, Fuchun (Tsinghua University) | Li, Hongbo (Tsinghua University) | Huang, Wenbing (Tsinghua University) | Aye, Zay Maung Maung (The University of Melbourne)
Robotic tactile recognition aims at identifying target objects or environments from tactile sensory readings. The advancement of unsupervised feature learning and biological tactile sensing inspire us proposing the model of 3T-RTCN that performs spatio-temporal feature representation and fusion for tactile recognition. It decomposes tactile data into spatial and temporal threads, and incorporates the strength of randomized tiling convolutional networks. Experimental evaluations show that it outperforms some state-of-the-art methods with a large margin regarding recognition accuracy, robustness, and fault-tolerance; we also achieve an order-of-magnitude speedup over equivalent networks with pretraining and finetuning. Practical suggestions and hints are summarized in the end for effectively handling the tactile data.
Solving Transition-Independent Multi-Agent MDPs with Sparse Interactions
Scharpff, Joris (Delft University of Technology) | Roijers, Diederik M. (University of Amsterdam) | Oliehoek, Frans A. (University of Amsterdam andย University of Liverpool) | Spaan, Matthijs T. J. (Delft University of Technology) | Weerdt, Mathijs M. de (Delft University of Technology)
In cooperative multi-agent sequential decision making under uncertainty, agents must coordinate to find an optimal joint policy that maximises joint value. Typical algorithms exploit additive structure in the value function, but in the fully-observable multi-agent MDP (MMDP) setting such structure is not present. We propose a new optimal solver for transition-independent MMDPs, in which agents can only affect their own state but their reward depends on joint transitions. We represent these dependencies compactly in conditional return graphs (CRGs). Using CRGs the value of a joint policy and the bounds on partially specified joint policies can be efficiently computed. We propose CoRe, a novel branch-and-bound policy search algorithm building on CRGs. CoRe typically requires less runtime than available alternatives and finds solutions to previously unsolvable problems.
A Joint Model for Entity Set Expansion and Attribute Extraction from Web Search Queries
Zhang, Zhenzhong (Institute of Software, Chinese Academy of Sciences) | Sun, Le (Institute of Software, Chinese Academy of Sciences) | Han, Xianpei (Institute of Software, Chinese Academy of Sciences)
Entity Set Expansion (ESE) and Attribute Extraction (AE) are usually treated as two separate tasks in Information Extraction (IE). However, the two tasks are tightly coupled, and each task can benefit significantly from the other by leveraging the inherent relationship between entities and attributes. That is, 1) an attribute is important if it is shared by many typical entities of a class; 2) an entity is typical if it owns many important attributes of a class. Based on this observation, we propose a joint model for ESE and AE, which models the inherent relationship between entities and attributes as a graph. Then a graph reinforcement algorithm is proposed to jointly mine entities and attributes of a specific class. Experimental results demonstrate the superiority of our method for discovering both new entities and new attributes.
Argument Mining from Speech: Detecting Claims in Political Debates
Lippi, Marco (University of Bologna) | Torroni, Paolo (University of Bologna)
The automatic extraction of arguments from text, also known as argument mining, has recently become a hot topic in artificial intelligence. Current research has only focused on linguistic analysis. However, in many domains where communication may be also vocal or visual, paralinguistic features too may contribute to the transmission of the message that arguments intend to convey. For example, in political debates a crucial role is played by speech. The research question we address in this work is whether in such domains one can improve claim detection for argument mining, by employing features from text and speech in combination. To explore this hypothesis, we develop a machine learning classifier and train it on an original dataset based on the 2015 UK political elections debate.