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Wednesday, July 19, 2023

Automated Evolution Tackles Tough Tasks

Automating Evolution

Automated Evolution Tackles Tough Tasks

By R. Colin Johnson.July 13, 2023

The intersection of natural and evolutionary computation in the context of machine learning and natural computation.

Credit: Evolutionary Machine Learning: A Survey, AKBAR TELIKANI et al, https://doi.org/10.1145/3467477

Deep neural networks (DNNs) that use reinforcement learning (RL, which explores a space of random decisions for winning combinations) can create algorithms that rival those produced by humans for games, natural language processing (NLP), computer vision (CV), education, transportation, finance, healthcare, and robotics, according to the seminal paper Introduction to Deep Reinforcement Learning (DRL).

Unfortunately, the successes of DNNs are getting harder to come by, due to sensitivity to the initial hyper-parameters chosen (such as the width and depth of the DNN, as well as other application-specific initial conditions). However, these limitations have recently been overcome by combining RL with evolutionary computation (EC), which maintains a population of learning agents, each with unique initial conditions, that together "evolve" an optimal solution, according to Ran Cheng and colleagues at the Southern University of Science and Technology, Shenzhen, China, in cooperation with Germany's Bielefeld University and the U.K.'s University of Surrey.

By choosing from among many evolving learning agents (each with different initial conditions), Evolutionary Reinforcement Learning(EvoRL) is extending the intelligence of DRL into hard-to-solve cross-disciplinary human tasks like autonomous cars and robots, according to Jurgen Branke, a professor of Operational Research and Systems at the U.K.'s University of Warwick, and editor-in-chief of ACM's new journal Transactions on Evolutionary Learning and Optimization

Said Branke, "Nature is using two ways of adaptation: evolution and learning. So it seems not surprising that the combination of these two paradigms is also successful 'in-silico' [that is, algorithmic 'evolution' akin to 'in-vivo' biological evolution]."

Reinforcement Learning

Reinforcement learning is the newest of three primary learning algorithms for deep neural networks (DNNs differ from the seminal three-layer perceptron by adding many inner layers, the function of which are not fully understood by its programmers—referred to as a black box). The first two prior primary DNN learning methods were supervised—learning from data labeled by humans (such as photographs of birds, cars, and flowers, each labeled as such) in order to learn to recognize and automatically label new photographs. The second-most-popular learning method was unsupervised, which groups unlabeled data into likes and dislikes, based on commonalities found by the DNN's black box.

Reinforcement learning, on the other hand, groups unlabeled data into sets of likes, but with the goal of maximizing the cumulative rewards it receives from a human-wrought evaluation function. The result is a DNN that uses RL to outperform other learning methods, albeit while still using internal layers that do not fit into a knowable mathematical model. For instance, in game theory, the cumulative rewards would be winning games. 'Optimization' is often used to describe the methodology obtained by reinforcement learning, according to Marco Wiering at the University of Groningen (The Netherlands) and Martijn Otterlo at Radboud University (Nijmegen, The Netherlands) in their 2012 paper Reinforcement Learning, although there is no way to prove that "optimal behavior" found with RL is the "most" optimal solution.   ... ' 

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