win percentage
Seven games, 20 goals, none conceded - England close in on perfection
England have cruised through World Cup qualifying, winning all seven of their games and scoring 20 unanswered goals, setting several records and leaving them on the cusp of another. If Thomas Tuchel's team beat Albania in Sunday's final qualifier (17:00 GMT) and keep a clean sheet, they will become the first European side to play at least six qualifiers and win them all without conceding. A clean sweep of victories - regardless of goals conceded - is also a rare achievement. Excluding the early years of the World Cup, when teams often played just a handful of preliminary matches, only four European countries have finished with a 100% winning record. Germany were the last side to do so on the way to the 2018 tournament, though they went on to suffer a shock early exit in Russia.
Enhancements for Real-Time Monte-Carlo Tree Search in General Video Game Playing
Soemers, Dennis J. N. J., Sironi, Chiara F., Schuster, Torsten, Winands, Mark H. M.
General Video Game Playing (GVGP) is a field of Artificial Intelligence where agents play a variety of real-time video games that are unknown in advance. This limits the use of domain-specific heuristics. Monte-Carlo Tree Search (MCTS) is a search technique for game playing that does not rely on domain-specific knowledge. This paper discusses eight enhancements for MCTS in GVGP; Progressive History, N-Gram Selection Technique, Tree Reuse, Breadth-First Tree Initialization, Loss Avoidance, Novelty-Based Pruning, Knowledge-Based Evaluations, and Deterministic Game Detection. Some of these are known from existing literature, and are either extended or introduced in the context of GVGP, and some are novel enhancements for MCTS. Most enhancements are shown to provide statistically significant increases in win percentages when applied individually. When combined, they increase the average win percentage over sixty different games from 31.0% to 48.4% in comparison to a vanilla MCTS implementation, approaching a level that is competitive with the best agents of the GVG-AI competition in 2015.
Beyond Suspension: A Two-phase Methodology for Concluding Sports Leagues
Hassanzadeh, Ali, Hosseini, Mojtaba, Turner, John G.
Problem definition: Professional sports leagues may be suspended due to various reasons such as the recent COVID-19 pandemic. A critical question the league must address when re-opening is how to appropriately select a subset of the remaining games to conclude the season in a shortened time frame. Academic/practical relevance: Despite the rich literature on scheduling an entire season starting from a blank slate, concluding an existing season is quite different. Our approach attempts to achieve team rankings similar to that which would have resulted had the season been played out in full. Methodology: We propose a data-driven model which exploits predictive and prescriptive analytics to produce a schedule for the remainder of the season comprised of a subset of originally-scheduled games. Our model introduces novel rankings-based objectives within a stochastic optimization model, whose parameters are first estimated using a predictive model. We introduce a deterministic equivalent reformulation along with a tailored Frank-Wolfe algorithm to efficiently solve our problem, as well as a robust counterpart based on min-max regret. Results: We present simulation-based numerical experiments from previous National Basketball Association (NBA) seasons 2004--2019, and show that our models are computationally efficient, outperform a greedy benchmark that approximates a non-rankings-based scheduling policy, and produce interpretable results. Managerial implications: Our data-driven decision-making framework may be used to produce a shortened season with 25-50\% fewer games while still producing an end-of-season ranking similar to that of the full season, had it been played.
Generating Real-Time Strategy Game Units Using Search-Based Procedural Content Generation and Monte Carlo Tree Search
Sorochan, Kynan, Guzdial, Matthew
Real-Time Strategy (RTS) game unit generation is an unexplored area of Procedural Content Generation (PCG) research, which leaves the question of how to automatically generate interesting and balanced units unanswered. Creating unique and balanced units can be a difficult task when designing an RTS game, even for humans. Having an automated method of designing units could help developers speed up the creation process as well as find new ideas. In this work we propose a method of generating balanced and useful RTS units. We draw on Search-Based PCG and a fitness function based on Monte Carlo Tree Search (MCTS). We present ten units generated by our system designed to be used in the game microRTS, as well as results demonstrating that these units are unique, useful, and balanced.
Wimbledon scientists reveal the luckiest and unluckiest courts for British tennis players
British stars Emma Raducanu and Andy Murray are among the British players kicking off their Wimbledon campaigns on Centre Court today, marking the first day of this year's hotly-anticipated tennis Championships. For any tennis player, a match on Centre Court is a highlight of the annual calendar – not only is it the biggest stage at the world's most prestigious tennis tournament, but a chance to perform in front of distinguished guests, including the Royal family. However, whether or not it's the best place to secure a win for homegrown tennis stars is another matter. Researchers at IBM, the official technology partner of The Championships, have trawled through 21 years of data to find the Wimbledon court with the best British win percentage so far this century. The data covers all Gentlemen's and Ladies' singles matches on all Wimbledon courts going back to 2000, when IBM's records start, captured using its IBM Watson AI software.
Bandit Modeling of Map Selection in Counter-Strike: Global Offensive
Petri, Guido, Stanley, Michael H., Hon, Alec B., Dong, Alexander, Xenopoulos, Peter, Silva, Cláudio
Many esports use a pick and ban process to define the parameters of a match before it starts. In Counter-Strike: Global Offensive (CSGO) matches, two teams first pick and ban maps, or virtual worlds, to play. Teams typically ban and pick maps based on a variety of factors, such as banning maps which they do not practice, or choosing maps based on the team's recent performance. We introduce a contextual bandit framework to tackle the problem of map selection in CSGO and to investigate teams' pick and ban decision-making. Using a data set of over 3,500 CSGO matches and over 25,000 map selection decisions, we consider different framings for the problem, different contexts, and different reward metrics. We find that teams have suboptimal map choice policies with respect to both picking and banning. We also define an approach for rewarding bans, which has not been explored in the bandit setting, and find that incorporating ban rewards improves model performance. Finally, we determine that usage of our model could improve teams' predicted map win probability by up to 11% and raise overall match win probabilities by 19.8% for evenly-matched teams.
General Game Heuristic Prediction Based on Ludeme Descriptions
Stephenson, Matthew, Soemers, Dennis J. N. J., Piette, Eric, Browne, Cameron
This paper investigates the performance of different general-game-playing heuristics for games in the Ludii general game system. Based on these results, we train several regression learning models to predict the performance of these heuristics based on each game's description file. We also provide a condensed analysis of the games available in Ludii, and the different ludemes that define them.
Transfer of Fully Convolutional Policy-Value Networks Between Games and Game Variants
Soemers, Dennis J. N. J., Mella, Vegard, Piette, Eric, Stephenson, Matthew, Browne, Cameron, Teytaud, Olivier
In this paper, we use fully convolutional architectures in AlphaZero-like self-play training setups to facilitate transfer between variants of board games as well as distinct games. We explore how to transfer trained parameters of these architectures based on shared semantics of channels in the state and action representations of the Ludii general game system. We use Ludii's large library of games and game variants for extensive transfer learning evaluations, in zero-shot transfer experiments as well as experiments with additional fine-tuning time.
Minimax Strikes Back
Cohen-Solal, Quentin, Cazenave, Tristan
Deep Reinforcement Learning (DRL) reaches a superhuman level of play in many complete information games. The state of the art search algorithm used in combination with DRL is Monte Carlo Tree Search (MCTS). We take another approach to DRL using a Minimax algorithm instead of MCTS and learning only the evaluation of states, not the policy. We show that for multiple games it is competitive with the state of the art DRL for the learning performances and for the confrontations.
Biasing MCTS with Features for General Games
Soemers, Dennis J. N. J., Piette, Éric, Browne, Cameron
This paper proposes using a linear function approximator, rather than a deep neural network (DNN), to bias a Monte Carlo tree search (MCTS) player for general games. This is unlikely to match the potential raw playing strength of DNNs, but has advantages in terms of generality, interpretability and resources (time and hardware) required for training. Features describing local patterns are used as inputs. The features are formulated in such a way that they are easily interpretable and applicable to a wide range of general games, and might encode simple local strategies. We gradually create new features during the same self-play training process used to learn feature weights. We evaluate the playing strength of an MCTS player biased by learnt features against a standard upper confidence bounds for trees (UCT) player in multiple different board games, and demonstrate significantly improved playing strength in the majority of them after a small number of self-play training games.