Deduction of fighting game countermeasures using Neuroevolution of Augmenting Topologies

摘要

Nowadays artificial intelligence (AI) has been applied to many areas, including digital game with various genres. One of them is the fighting game. Implementation of AI in the fighting game aims to make players who are not constrained by the limiting factors which humans possess, such as speed of reflexes and hand gestures. One platform that can be used to make fighting game AI is FightingICE. This platform is official platform used in Computational Intelligence and Games (CIG) conference. One approach that can be used in the process of building the AI in the fighting game is opponent modeling, a method that utilize machine learning to make model based on the behavior of the opponent. There is one AI that utilize k-Nearest Neighbor (kNN) algorithm called MizunoAI. This AI has outstanding performance, but it suffers from inability to adjust its parameter automatically. To solve that problem, in this paper the algorithm used for modelling is changed to Neuroevolution of Augmenting Topologies (NEAT). NEAT is an algorithm with Artificial Neural Network (ANN) as basic architecture and Genetic Algorithm (GA) as the architecture optimizer. In the implementation, NEAT will receive six inputs of distance in the x-axis and y-axis, both players' hitpoints, and both players' stamina. Output of NEAT is the probability of all movements that can be done by the opponent. The entire output will be processed by a simulator to determine the best countermeasure based on the predictions. For testing, the AI made will be faced against four AI winners of CIG 2013, namely MizunoAI, Kaiju, T, and SejongAI. The results showed that the AI is capable to do well in modeling process. Although the performance is still behind the MizunoAI, the learning process can be seen along the match.