Universidade Federal de Viçosa
Semantic Labeling of English Texts with Ontological Categories Employing Recurrent Networks
Silva, Roberta Caroline Rodrigues (Universidade Federal de Viçosa) | Oliveira, Alcione de Paiva (Universidade Federal de Viçosa) | Moreira, Alexandra (Universidade Federal de Viçosa)
Semantic labeling of texts allows people and computing devices to more easily understand the meaning of a natural language sentence as a whole. It is very often one of the steps taken of procedures related to natural language processing. However, this step is often done manually, which is very expensive and time-consuming. When automatic labeling systems are employed, methods such as maximum entropy models are used, which receive as input features specified by specialists that also make the development of the system more expensive. In this article we present a model of the deep recurrent network that semantically annotates texts in English using as labels the top categories of an ontology. The tests showed that it is possible to obtain better results than the models that need the features to be made explicit.
Action Abstractions for Combinatorial Multi-Armed Bandit Tree Search
Moraes, Rubens O. (Universidade Federal de Viçosa) | Mariño, Julian R. H. (Universidade de São Paulo) | Lelis, Levi H. S. (Universidade Federal de Viçosa) | Nascimento, Mario A. (University of Alberta)
Search algorithms based on combinatorial multi-armed bandits (CMABs) are promising for dealing with state-space sequential decision problems. However, current CMAB-based algorithms do not scale to problem domains with very large actions spaces, such as real-time strategy games played in large maps. In this paper we introduce CMAB-based search algorithms that use action abstraction schemes to reduce the action space considered during search. One of the approaches we introduce use regular action abstractions (A1N), while the other two use asymmetric action abstractions (A2N and A3N). Empirical results on MicroRTS show that A1N, A2N, and A3N are able to outperform an existing CMAB-based algorithm in matches played in large maps, and A3N is able to outperform all state-of-the-art search algorithms tested.
Nested-Greedy Search for Adversarial Real-Time Games
Moraes, Rubens O. (Universidade Federal de Viçosa) | Mariño, Julian R. H. (Universidade de São Paulo) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
Churchill and Buro (2013) launched a line of research through Portfolio Greedy Search (PGS), an algorithm for adversarial real-time planning that uses scripts to simplify the problem's action space. In this paper we present a problem in PGS's search scheme that has hitherto been overlooked. Namely, even under the strong assumption that PGS is able to evaluate all actions available to the player, PGS might fail to return the best action. We then describe an idealized algorithm that is guaranteed to return the best action and present an approximation of such algorithm, which we call Nested-Greedy Search (NGS). Empirical results on MicroRTS show that NGS is able to outperform PGS as well as state-of-the-art methods in matches played in small to medium-sized maps.
The First microRTS Artificial Intelligence Competition
Ontañón, Santiago (Drexel University) | Barriga, Nicolas A. (University of Alberta) | Silva, Cleyton R. (Universidade Federal de Viçosa) | Moraes, Rubens O. (Universidade Federal de Viçosa) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
This article presents the results of the first edition of the microRTS (μRTS) AI competition, which was hosted by the IEEE Computational Intelligence in Games (CIG) 2017 conference. The goal of the competition is to spur research on AI techniques for real-time strategy (RTS) games. In this first edition, the competition received three submissions, focusing on address- ing problems such as balancing long-term and short-term search, the use of machine learning to learn how to play against certain opponents, and finally, dealing with partial observability in RTS games.
Asymmetric Action Abstractions for Multi-Unit Control in Adversarial Real-Time Games
Moraes, Rubens O. (Universidade Federal de Viçosa) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
Action abstractions restrict the number of legal actions available during search in multi-unit real-time adversarial games, thus allowing algorithms to focus their search on a set of promising actions. Optimal strategies derived from un-abstracted spaces are guaranteed to be no worse than optimal strategies derived from action-abstracted spaces. In practice, however, due to real-time constraints and the state space size, one is only able to derive good strategies in un-abstracted spaces in small-scale games. In this paper we introduce search algorithms that use an action abstraction scheme we call asymmetric abstraction. Asymmetric abstractions retain the un-abstracted spaces' theoretical advantage over regularly abstracted spaces while still allowing the search algorithms to derive effective strategies, even in large-scale games. Empirical results on combat scenarios that arise in a real-time strategy game show that our search algorithms are able to substantially outperform state-of-the-art approaches.
Bardo: Emotion-Based Music Recommendation for Tabletop Role-Playing Games
Padovani, Rafael R. (Universidade Federal de Viçosa) | Ferreira, Lucas N. (University of California, Santa Cruz) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
In this paper we introduce Bardo, a real-time intelligent system to automatically select the background music for tabletop role-playing games. Bardo uses an off-the-shelf speech recognition system to transform into text what the players say during a game session, and a supervised learning algorithm to classify the text into an emotion. Bardo then selects and plays as background music a song representing the classified emotion. We evaluate Bardo with a Dungeons and Dragons (D&D) campaign available on YouTube. Accuracy experiments show that a simple Naive Bayes classifier is able to obtain good prediction accuracy in our classification task. A user study in which people evaluated edited versions of the D&D videos suggests that Bardo's selections can be better than those used in the original videos of the campaign.
A Computational Model Based on Symmetry for Generating Visually Pleasing Maps of Platform Games
Mariño, Julian R. H. (Universidade Federal de Viçosa) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
In this paper we introduce a computational model based on the concept of symmetry to generate visually pleasing maps of platform games. We cast the problem of generating symmetrical maps as an optimization task and propose a heuristic search algorithm to solve it. A user study using a platform game shows the advantage of our method over other approaches in terms of visual aesthetics and enjoyment. Another user study shows that our method is able to generate maps as visually pleasing as maps created by professional designers.
An Empirical Evaluation of Evaluation Metrics of Procedurally Generated Mario Levels
Mariño, Julian R. H. (Universidade Federal de Viçosa) | Reis, Willian M. P. (Universidade Federal de Viçosa) | Lelis, Levi H. S. (Universidade Federal de Viçosa)
There are several approaches in the literature for automatically generating Infinite Mario Bros levels. The evaluation of such approaches is often performed solely with computational metrics such as leniency and linearity. While these metrics are important for an initial exploratory evaluation of the content generated, it is not clear whether they are able to capture the player's perception of the content generated. In this paper we evaluate several of the commonly used computational metrics. Namely, we perform a systematic user study with procedural content generation systems and compare the insights gained from our user study with those gained from analyzing the computational metric values. The results of our experiment suggest that current computational metrics should not be used in lieu of user studies for evaluating content generated by computer programs.