ViZDoom Competitions: Playing Doom from Pixels

This paper presents the first two editions of Visual Doom AI Competition, held in 2016 and 2017. The challenge was to create bots that compete in a multi-player deathmatch in a first-person shooter (FPS) game, Doom. The bots had to make their decisions based solely on visual information, i.e., a raw screen buffer. To play well, the bots needed to understand their surroundings, navigate, explore, and handle the opponents at the same time. These aspects, together with the competitive multi-agent aspect of the game, make the competition a unique platform for evaluating the state of the art reinforcement learning algorithms. The paper discusses the rules, solutions, results, and statistics that give insight into the agents' behaviors. Best-performing agents are described in more detail. The results of the competition lead to the conclusion that, although reinforcement learning can produce capable Doom bots, they still are not yet able to successfully compete against humans in this game. The paper also revisits the ViZDoom environment, which is a flexible, easy to use, and efficient 3D platform for research for vision-based reinforcement learning, based on a well-recognized first-person perspective game Doom

Thermo-mechanical Simulations Confirm: Temperature-dependent Mudrock Properties are Nice to have in Far-field Environmental Assessments of Underground Coal Gasification

AbstractCoupled thermo-mechanical simulations were carried out to quantify permeability changes in representative coal measure strata surrounding an underground coal gasification (UCG) reactor. Comparing temperature-dependent and -independent rock properties applied in our simulations, notable differences in rock failure behavior, but only insignificant differences in spatial permeability development are observed. Hence, temperature-dependent parameters are required for simulations of the close reactor vicinity, while far-field models can be sufficiently determined by temperature-independent parameters. Considering our findings in the large-scale assessment of potential environmental impacts of UCG, representative coupled simulations based on complex thermo-hydro-mechanical and regional-scale models become computationally feasible

Decompositions with atoms and molecules for variable exponent Triebel-Lizorkin-Morrey spaces

We continue the study of the variable exponent Morreyfied Triebel-Lizorkin spaces introduced in a previous paper. Here we give characterizations by means of atoms and molecules. We also show that in some cases the number of zero moments needed for molecules, in order that an infinite linear combination of them (with coefficients in a natural sequence space) converges in the space of tempered distributions, is much smaller than what is usually required. We also establish a Sobolev type theorem for related sequence spaces, which might have independent interest.publishe