Human Activity Recognition has been researched in thousands of papers so far, with mobile / environmental sensors in ubiquitous / pervasive domains, and with cameras in vision domains. As well, Human Behavior Analysis is also explored for long-term health care, rehabilitation, emotion recognition, human interaction, and so on. However, many research challenges remain for realistic settings, such as complex and ambiguous activities / behavior, optimal sensor combinations, (deep) machine learning, data collection, platform systems, and killer applications. In this conference, we comprehend such research domains as ABC: Activity and Behavior Computing, and provide an open and a confluent place for discussing various aspects and the future of the ABC.