Introduction to the Special Issue on Affective Services based on Representation Learning

With advances in machine learning and artificial intelligence, a considerable impact is brought to all aspects of people’s lifestyles in terms of work, social, and economy. Especially, representation learning, which is one of the most crucial roles of deep learning, is developing rapidly and has been applied to many areas. Representation learning is expected to discover useful features or representations from complex, redundant, and highly variable data, such as images, video, and sensory data. In particular, through representation learning, a machine is available to learn the features rather than use the features.