Evolutionary Systems
Intelligent Content Generation via Abstraction, Evolution and Reinforcement
LeBaron, Dean M. (Brigham Young University) | Mitchell, Logan A. (Brigham Young University) | Ventura, Dan (Brigham Young University)
We present a system for autonomously generating puzzles in the form of a 2D, tile-based world. ย Puzzle design is entirely dependent on tile characteristics, which are implemented as abstract classes that can be modified by the system. ย Thus, the system controls not only the base-level puzzle design but also (to some extent) the meta-level component design. ย The result is a rich space of possible puzzles that the system explores with a combination of evolutionary computation and Q -learning. ย The system autonomously produces a variety of puzzles of varying difficulty to create a game called Loki's Castle . ย The system is almost completely autonomous, requiring only a minimal description of what a puzzle should include, and the abstraction allows extensibility so that future versions can invent entirely new classes of tiles. ย Several puzzle examples are presented to demonstrate the system's capability.
Refining the Paradigm of Sketching in AI-Based Level Design
Liapis, Antonios (University of Malta) | Yannakakis, Georgios N. (University of Malta)
This paper describes computational processes which can simulate how human designers sketch and then iteratively refine their work. The paper uses the concept of a map sketch as an initial, low-resolution and low-fidelity prototype of a game level, and suggests how such map sketches can be refined computationally. Different case studies with map sketches of different genres showcase how refinement can be achieved via increasing the resolution of the game level, increasing the fidelity of the function which evaluates it, or a combination of the two. While these case studies use genetic algorithms to automatically generate levels at different degrees of refinement, the general method described in this paper can be used with most procedural generation methods, as well as for AI-assisted design alongside a human creator.
Multi-Level Evolution of Shooter Levels
Cachia, William (University of Malta) | Liapis, Antonios (University of Malta) | Yannakakis, Georgios N. (University of Malta)
This paper introduces a search-based generative process for first person shooter levels. Genetic algorithms evolve the level's architecture and the placement of powerups and player spawnpoints, generating levels with one floor or two floors. The evaluation of generated levels combines metrics collected from simulations of artificial agents competing in the level and theory-based heuristics targeting general level design patterns. Both simulation-based and theory-driven evaluations target player balance and exploration, while resulting levels emergently exhibit several popular design patters of shooter levels.
Targeting Horror via Level and Soundscape Generation
Lopes, Phil (University of Malta) | Liapis, Antonios (University of Malta) | Yannakakis, Georgios N. (University of Malta)
Horror games form a peculiar niche within game design paradigms, as they entertain by eliciting negative emotions such as fear and unease to their audience during play. This genre often follows a specific progression of tension culminating at a metaphorical peak, which is defined by the designer. A player's tension is elicited by several facets of the game, including its mechanics, its sounds, and the placement of enemies in its levels. This paper investigates how designers can control and guide the automated generation of levels and their soundscapes by authoring the intended tension of a player traversing them.
A Model for Foraging Ants, Controlled by Spiking Neural Networks and Double Pheromones
Jimenez-Romero, Cristian, Sousa-Rodrigues, David, Johnson, Jeffrey H., Ramos, Vitorino
A model of an Ant System where ants are controlled by a spiking neural circuit and a second order pheromone mechanism in a foraging task is presented. A neural circuit is trained for individual ants and subsequently the ants are exposed to a virtual environment where a swarm of ants performed a resource foraging task. The model comprises an associative and unsupervised learning strategy for the neural circuit of the ant. The neural circuit adapts to the environment by means of classical conditioning. The initially unknown environment includes different types of stimuli representing food and obstacles which, when they come in direct contact with the ant, elicit a reflex response in the motor neural system of the ant: moving towards or away from the source of the stimulus. The ants are released on a landscape with multiple food sources where one ant alone would have difficulty harvesting the landscape to maximum efficiency. The introduction of a double pheromone mechanism yields better results than traditional ant colony optimization strategies. Traditional ant systems include mainly a positive reinforcement pheromone. This approach uses a second pheromone that acts as a marker for forbidden paths (negative feedback). This blockade is not permanent and is controlled by the evaporation rate of the pheromones. The combined action of both pheromones acts as a collective stigmergic memory of the swarm, which reduces the search space of the problem. This paper explores how the adaptation and learning abilities observed in biologically inspired cognitive architectures is synergistically enhanced by swarm optimization strategies. The model portraits two forms of artificial intelligent behaviour: at the individual level the spiking neural network is the main controller and at the collective level the pheromone distribution is a map towards the solution emerged by the colony.
Model Guided Sampling Optimization for Low-dimensional Problems
Optimization of very expensive black-box functions requires utilization of maximum information gathered by the process of optimization. Model Guided Sampling Optimization (MGSO) forms a more robust alternative to Jones' Gaussian-process-based EGO algorithm. Instead of EGO's maximizing expected improvement, the MGSO uses sampling the probability of improvement which is shown to be helpful against trapping in local minima. Further, the MGSO can reach close-to-optimum solutions faster than standard optimization algorithms on low dimensional or smooth problems.
On the Runtime of Randomized Local Search and Simple Evolutionary Algorithms for Dynamic Makespan Scheduling
Neumann, Frank (The University of Adelaide) | Witt, Carsten (Technical University of Denmark)
Evolutionary algorithms have been frequently used for dynamic optimization problems. With this paper, we contribute to the theoretical understanding of this research area. We present the first computational complexity analysis of evolutionary algorithms for a dynamic variant of a classical combinatorial optimization problem, namely makespan scheduling. We study the model of a strong adversary which is allowed to change one job at regular intervals. Furthermore, we investigate the setting of random changes.
Evolving Families of Shapes
Assunรงรฃo, Filipe (University of Coimbra) | Correia, Joรฃo (University of Coimbra) | Martins, Pedro (University of Coimbra) | Machado, Penousal (University of Coimbra)
Visual families are seen as sets of artifacts that share common visual features allowing one to intuitively classify them as belonging to the same family. An evolutionary approach for the creation of such families of shapes, where each genotype encodes a visual language by means of a non-deterministic grammar is explored.
Collective Biobjective Optimization Algorithm for Parallel Test Paper Generation
Nguyen, Minh Luan (Institute for Infocomm Research) | Hui, Siu Cheung (Nanyang Technological University) | Fong, Alvis C. M. (University of Glasgow)
Parallel Test Paper Generation ( k -TPG) is a biobjective distributed resource allocation problem, which aims to generate multiple similarly optimal test papers automatically according to multiple user-specified criteria.Generating high-quality parallel test papers is challenging due to its NP-hardness in maximizing the collective objective functions.In this paper, we propose a Collective Biobjective Optimization (CBO) algorithm for solving k -TPG. CBO is a multi-step greedy-based approximation algorithm, which exploits the submodular property for biobjective optimization of k -TPG.Experiment results have shown that CBO has drastically outperformed the current techniques in terms of paper quality and runtime efficiency.