9,398 research outputs found
A Review of Text-to-Animation Systems
Text-to-graphics systems encompass three types of tools: text-to-picture, text-to-scene and text-to-animation. They are an artificial intelligence application wherein users can create 2D and 3D scenes or animations and recently immersive environments from natural language. These complex tasks require the collaboration of various fields, such as natural language processing, computational linguistics and computer graphics. Text-to-animation systems have received more interest than their counterparts, and have been developed for various domains, including theatrical pre-production, education or training. In this survey we focus on text-to-animation systems, discussing their requirements, challenges and proposing solutions, and investigate the natural language understanding approaches adopted in previous research works to solve the challenge of animation generation. We review text-to-animation systems developed over the period 2001-2021, and investigate their recent trends in order to paint the current landscape of the field
Phylogenies and the forces of evolution
The construction of phylogenetic trees from gene frequency data assumes that a history of binary fissioning of populations has been the major cause of genetic variation. However, in many areas of the world human populations have been relatively stable with local gene flow. This population history is closer to an isolation by distance model. It was modelled by a simulation of gene frequency changes in a linear sequence of 50 stable populations with gene flow among neighboring populations. Phylogenetic trees were constructed from the gene frequencies after the simulation was run for 500 generations. Using only a few loci there is little correlation between genetic and geographic distance, but with 40 or more loci, there was a perfect correlation with geographic distance. A different population model can thus result in a phylogenetic tree comparable to those assumed to be produced by binary fission.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38549/1/1310030202_ftp.pd
Genetic drift at expanding frontiers promotes gene segregation
Competition between random genetic drift and natural selection plays a
central role in evolution: Whereas non-beneficial mutations often prevail in
small populations by chance, mutations that sweep through large populations
typically confer a selective advantage. Here, however, we observe chance
effects during range expansions that dramatically alter the gene pool even in
large microbial populations. Initially well-mixed populations of two
fluorescently labeled strains of Escherichia coli develop well-defined,
sector-like regions with fractal boundaries in expanding colonies. The
formation of these regions is driven by random fluctuations that originate in a
thin band of pioneers at the expanding frontier. A comparison of bacterial and
yeast colonies (Saccharomyces cerevisiae) suggests that this large-scale
genetic sectoring is a generic phenomenon that may provide a detectable
footprint of past range expansions.Comment: Please visit http://www.pnas.org/content/104/50/19926.abstract for
published articl
Vers un modèle pour le recueil d’un corpus d’apprentissage d’une langue étrangère peu dotée de ressources
How to make experimental economics research more reproducible: lessons from other disciplines and a new proposal
Efforts in the spirit of this special issue aim at improving the reproducibility of experimental economics, in response to the recent discussions regarding the “research reproducibility crisis.” We put this endeavour in perspective by summarizing the main ways (to our knowledge) that have been proposed – by researchers from several disciplines – to alleviate the problem. We discuss the scope for economic theory to contribute to evaluating the proposals. We argue that a potential key impediment to replication is the expectation of negative reactions by the authors of the individual study, and suggest that incentives for having one’s work replicated should increase
- …