Welcome Message from the Organizers
In the past three editions of RESACS, submitted papers and workshop discussions have proven useful to presenting authors and attending audience alike, resulting in new impulses in shaping this still novel and wide-spread field. For the fourth edition of RESACS, the tradition of RESACS was continued. In a highly interactive workshop the arising challenges in the emergent field of self-adaptive, collaborative, and cyber physical systems were discussed, positioned, and addressed. Thought-provoking and highly constructive discussions among a broader audience and presenters jointly identified properties of these types of system, what their properties entail, which challenges emerge due to these properties, and how traditional, contemporary, and novel approaches might address these challenges for requirements engineering in particular, but also software engineering in general. We hope that the results of the RESACS workshop will spawn research ideas, and standardization of terminology in SAS and CPS research, validate existing research avenues, foster empirical studies, and facilitate collaboration between industry and academia for software engineering as a whole.