3,132 research outputs found
A guided tour of asynchronous cellular automata
Research on asynchronous cellular automata has received a great amount of
attention these last years and has turned to a thriving field. We survey the
recent research that has been carried out on this topic and present a wide
state of the art where computing and modelling issues are both represented.Comment: To appear in the Journal of Cellular Automat
An artificial life approach to evolutionary computation: from mobile cellular algorithms to artificial ecosystems
This thesis presents a new class of evolutionary algorithms called mobile cellular evolutionary algorithms (mcEAs). These algorithms are characterized by individuals moving around on a spatial population structure. As a primary objective, this thesis aims to show that by controlling the population density and mobility in mcEAs, it is possible to achieve much better control over the rate of convergence than what is already possible in existing cellular EAs. Using the observations and results from this investigation into selection pressure in mcEAs, a general architecture for developing agent-based evolutionary algorithms called Artificial Ecosystems (AES) is presented. A simple agent-based EA is developed within the scope of AES is presented with two individual-based bottom-up schemes to achieve dynamic population sizing. Experiments with a test suite of optimization problems show that both mcEAs and the agent-based EA produced results comparable to the best solutions found by cellular EAs --Abstract, page iii
Comparative analysis of asynchronous cellular automata in stochastic pharmaceutical modelling
In pharmaceutical modelling, cellular automata have been used as an established tool to represent molecular changes through discrete structural interactions. The data quality provided by such modelling is found suitable for the early drug design phase where flexibility is paramount. While both synchronous (CA) and asynchronous (ACA) types of automata have been used, analysis of their nature and comparative influence on model outputs is lacking. In this paper, we outline a representative probabilistic CA for modelling complex controlled drug formulations and investigate its transition from synchronous to asynchronous update algorithms. The key investigation points include quantification of model dynamics through three distinct scenarios, parallelisation performance and the ability to describe different release phenomena, namely erosion, diffusion and swelling. The choice of the appropriate update mechanism impacts the perceived realism of the simulation as well as the applicability of large-scale simulations
Asynchronous Evolution of Deep Neural Network Architectures
Many evolutionary algorithms (EAs) take advantage of parallel evaluation of
candidates. However, if evaluation times vary significantly, many worker nodes
(i.e.,\ compute clients) are idle much of the time, waiting for the next
generation to be created. Evolutionary neural architecture search (ENAS), a
class of EAs that optimizes the architecture and hyperparameters of deep neural
networks, is particularly vulnerable to this issue. This paper proposes a
generic asynchronous evaluation strategy (AES) that is then adapted to work
with ENAS. AES increases throughput by maintaining a queue of upto
individuals ready to be sent to the workers for evaluation and proceeding to
the next generation as soon as individuals have been evaluated by the
workers. A suitable value for is determined experimentally, balancing
diversity and efficiency. To showcase the generality and power of AES, it was
first evaluated in 11-bit multiplexer design (a single-population verifiable
discovery task) and then scaled up to ENAS for image captioning (a
multi-population open-ended-optimization task). In both problems, a multifold
performance improvement was observed, suggesting that AES is a promising method
for parallelizing the evolution of complex systems with long and variable
evaluation times, such as those in ENAS
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