Distributed Complex Systems (e.g., Systems of Systems - SoSs) are gaining momentum due to the widespread adoption of Internet of Things (IoT) technologies and the increasing interest for smart cities, digital twins, and industrial cyber physical systems. The heterogeneity and large scale of these systems require novel design techniques, architectures and software infrastructures able to integrate independent (sub)systems to support their seamless cooperation and to address their emergent behaviours.
In addition, the continuous servicing process enabled by the recent micro-services paradigm leads to rely on evolving approaches able to anticipate, mitigate, or react to unplanned scenarios.

Each part of a Distributed Complex System can both exist as an independent entity and become part of wider systems when needed.

This vision radically changes the notion of "integrated" system:
(a) (sub)systems offer limited inter-action capabilities and little possibility to be governed by other entities;
(b) cooperation can be ad-hoc and only needed in specific cases or conditions;
(c) in many cases there is no prior, complete, knowledge of the (sub)systems;
(d) the behaviour can be partially unplanned to follow environment or requirement changes.

The goal of this Special Issue is to bring together researchers and practitioners working on the design, the development, the validation, and the continuous maintenance of Distributed Complex Systems (e.g., SoSs, MultiAgent Systems, Adaptive Systems, Ambient Intelligent Systems).

Indeed, topics on dynamic modules integration, autonomous reaction to unplanned or dynamic scenarios, or dynamic evolution of operational and managerial assets are in the scope of this special issue.

== THE LIST OF RELEVANT TOPICS INCLUDE BUT IS NOT LIMITED TO: ==
* Modelling, design, and engineering of Distributed Complex Systems
* Architectures, architectural styles, architecture synthesis and middlewares for Distributed Complex Systems
* Foundations and formal methods for distributed complex systems
* Coordination and adaptation patterns
* Online V&V techniques for functional and non-functional assessment and dependability
* Online and offline testing techniques
* Context-awareness and context-aware adaptation techniques
* Reconfiguration and optimization techniques
* Self-* mechanisms
* Techniques for extracting behaviour models from streams of continuous observations
* Applications, experiences, case studies, benchmarking, industrial perspectives of Distributed Complex Systems
* Distributed software engineering: strategies, processes, evaluation and methods
* Models of functional and non functional requirements, context and governance policies to support integration of Distributed Complex Systems
* Knowledge management and decision-making process in Distributed Complex Systems
* Ambient intelligent and multi-agent systems
* Interaction platforms enabling heterogeneous entities participation
* Knowledge bases integration support and exploitation for semantic inter-operability
* Autonomic coordination, negotiation and interactions for multi-agent and complex systems
* Blockchain technology for distributed and heterogeneous systems
* Internet of Things-based Distributed Complex Systems
* Adaptive and reactive Distributed Complex Systems

== IMPORTANT DATES: ==
* Paper Submissions: 28 February 2021
* First Notification: 15 May 2021
* Revised papers Submission: 30 June 2021
* Final Notification: 10 August 2021

== GUEST EDITORS: ==
* Pietro Braione, University of Milano-Bicocca, Italy
* Daniela Briola, University of Milano-Bicocca, Italy
* Guglielmo De Angelis, CNR-IASI, Italy
* Francesco Gallo, University of L’Aquila, Italy
* Francesco Poggi, University of Modena and Reggio Emilia, Italy
* Giovanni Quattrocchi, Politecnico di Milano, Italy.

== EDITORS: ==
* Massimiliano Di Penta
* Darren Dalcher
* Xin Peng
* David Raffo