Multi-Criterion Evolutionary Design of Deep Convolutional Neural Networks

Convolutional neural networks (CNNs) are the backbones of deep learning paradigms for numerous vision tasks. Early advancements in CNN architectures are primarily driven by human expertise and elaborate design. Recently, neural architecture search was proposed with the aim of automating the network design process and generating task-dependent architectures. While existing approaches have achieved competitive performance in image classification, they are not well suited under limited computational budget for two reasons: (1) the obtained architectures are either solely optimized for classification performance or only for one targeted resource requirement; (2) the search process requires vast computational resources in most approaches. To overcome this limitation, we propose an evolutionary algorithm for searching neural architectures under multiple objectives, such as classification performance and FLOPs. The proposed method addresses the first shortcoming by populating a set of architectures to approximate the entire Pareto frontier through genetic operations that recombine and modify architectural components progressively. Our approach improves the computation efficiency by carefully down-scaling the architectures during the search as well as reinforcing the patterns commonly shared among the past successful architectures through Bayesian Learning. The integration of these two main contributions allows an efficient design of architectures that are competitive and in many cases outperform both manually and automatically designed architectures on benchmark image classification datasets, CIFAR, ImageNet and human chest X-ray. The flexibility provided from simultaneously obtaining multiple architecture choices for different compute requirements further differentiates our approach from other methods in the literature.