Due to their huge use, during the last decade cloud systems evolved a lot changing its architectures and integrating new technologies. Over the years, cloud systems evolved in to pervasive and ubiquitous global ICT platforms in which people, things, data, computing and storage resources are connected anytime and anyplace, with benefits from the social,environmental, and economical points of view. In this scenario, a growing number of both powerful and simple devices (smart phones, sensors, household appliances, and so on) joined the Internet and applications have been developed for users unaware of the underling technologies and resources used to provide services.

The overall scenario is made more complex when mobile application are considered.In this context adequate techniques and tools have to be used in order to asses functional and quantitative requirements of cloud architectures and application in all the different are awhere they are developed. This special issue aims to focus on tools, methodologies and successful case studies proving how applicative requirements may be reached in a such complex modern environment, both from users and providers point of views. Thus new architectural settings and applications supported by the evidence of effective behavior are the main subject of this special issue; at the same time, experimentation and simulation or modeling techniques aiming to teach how effective cloud systems and applications could be designed are welcome.

The papers will be peer reviewed and will be selected on the basis of their quality and relevance to the theme of the special issue.