Budapest University of Technology and Economics, Faculty of Electrical Engineering and Informatics

Since the course will also review basics when needed, only foundational knowledge of computer science is required, in particular:

• Basics of programming
• Basics of concurrent systems
• Basics of networking

A kötelező előtanulmányi rend az adott szak honlapján és képzési programjában található.

The course aims at providing solid knowledge and competencies to conceive, define, and design comp­lex cyber-physical systems (of systems) which are at the basis of emerging fields such as the Internet of Things, Smart Factories, and Critical Infrastructures. In particular, the focus is put on the distribution and coordination aspects of the constituent systems of a System-of-System (SoS).

In detail, first, the course will review the fundamentals of distributed systems. This will allow all students to clearly understand the fundamentals of distributed systems, the challenges and examples. Then, the course will introduce cyber-physical systems, and cyber-physical Systems of Systems (SoSes), which are the main subject of the course. The characteristics of these systems will be explored by analyzing different viewpoints: most emphasis will be dedicated to the architectural viewpoint, the interface viewpoint with the introduction of stigmergic channels to describe the physical interactions of the system, and the emergent behaviors which arise when building or operating SoSes. In addition, the course will review the fundamentals of dependability and real-time systems, which are relevant aspects when building SoSes.

Next, the course will shift its focus to algorithms and protocols for distributed coordination, as it is arguably a fundamental aspect of distributed systems and SoSes. The course will explore various coordination algorithms, starting from foundational results such as Lamport logical clock, reliable broadcast, Failure Detectors model, Byzantine Agreement, and Timed Asynchronous, until presenting consensus algorithms for blockchain, that give clear evidence the consensus challenge is a topic still researched and very relevant for computer scientists.

Last, the course will focus on how to design the architecture of an SoS. For this, we will review fundamentals of Model-Based Engineering, including a short recap on selected UML and SysML diagrams, and we will review requirements engineering principles to learn how to create a requirements specification document (with the support of use case diagrams and requirements diagrams). Next, we will explain how to build and apply a conceptual model with the support of UML profiles and Papyrus. This gives us the background to present a profile to design a System of Systems (the AMADEOS profile), where the reviewed concepts of SoS can be efficiently used.

Finally, a pilot use case will be presented covering the entire workflow explored during lectures with practical demos.

1.    Recap on distributed systems fundamentals: basic notions, examples, review of types of distributed systems (multi-threaded systems, server clusters, virtualizations, cloud computing), models for code migration (client-server, remote evaluation, code-on-demand, mobile agent), migration of virtual machine.

2.    Basic definitions and concepts of Systems of Systems: definitions, characteristics of (cyber-physical) systems of systems, basic architectures, the definition of boundaries, and categories of Systems of Systems.

3.    Architecting Systems of Systems: Interfaces in evolving cyber-physical Systems of Systems: exchange of information through relied-upon message interface and physical interfaces.

4.    Fundamental properties of Systems of Systems: Emergence in cyber-physical Systems of Systems: definition, the role of unknowns, managing emergence, examples of emergent behavior.

5.    Fundamental properties of Systems of Systems: Managing dynamicity and evolution in Systems of Systems: definitions, managed vs unmanaged evolution, the role of authority to coordinate evolution.

6.    Time and resilient Master Clock in Cyber-Physical Systems of Systems: time and clock synchronization, accurate time synchronization, identification and set-up of a master clock for resilient time synchronization.

7.    Coordination of distributed systems: system models (synchronous vs asynchronous) and failures classification; algorithms and protocols for distributed consensus (agreement): reliable broadcast, failure detector model, byzantine agreement.

8.    Coordination of distributed systems: consensus in timed-asynchronous systems, consensus for blockchains; basic approaches to distributed commit and recovery.

9.    Methodologies for the design and construction of systems: the role of models, modelling and Model-Based (and Model-Driven) Engineering, conceptual modeling with UML profiles. Examples and exercises.

10.  Methodologies for the design and construction of systems: requirements engineering principles and with SysML support. Examples and exercises.

11.  Methodologies for the design and construction of systems: conceptual modeling of Systems of Systems, definition of an UML profile to model Systems of Systems. Examples and exercises.

12.  Application of concepts of requirements engineering, modeling, and implementation (with a little of robotics) to architect a System of Systems.

Lectures.

The assessment is organized into two parts: a project and an oral interview.

a. During the semester: Students are requested to submit a project proposal. The project should be elaborated with the aid of the algorithms and methods presented during the lectures.

b. In the examination period: At the examination, a short presentation of the solution is followed by questions related to the methodology applied.

c. Early exams before the examination period: none.

As per the applicable regulations of the faculty and the university.

Appointments shall be made with the lecturers on a case-by-case basis.

Relevant resources are below. At the beginning of each lecture, the resources relevant for the specific lecture will be identified.

• Ceccarelli, Andrea, et al. "Basic concepts on systems of systems."Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy(2016): 1-39.
• Frömel, Bernhard, and Hermann Kopetz. "Interfaces in evolving cyber-physical systems-of-systems."Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy(2016): 40-72.
• Kopetz, Hermann, et al. "Emergence in cyber-physical systems-of-systems (CPSoSs)."Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy(2016): 73-96.
• Lollini, Paolo, et al. "Amadeos sysml profile for sos conceptual modeling."Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy(2016): 97-127.
• Ceccarelli, Andrea, et al. "Time and Resilient Master Clocks in Cyber-Physical Systems."Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy(2016): 165-185.
• Bouchenak, S., Brancati, F., Ceccarelli, A., Iacob, S., Marchand, N., Robu, B., & De Oude, P. (2016). Managing Dynamicity in SoS.Cyber-Physical Systems of Systems: Foundations-A Conceptual Model and Some Derivations: The AMADEOS Legacy, 186-206.

Recommended readings:

• Mori, M., Ceccarelli, A., Lollini, P., Frömel, B., Brancati, F., & Bondavalli, A. (2018). Systems‐of‐systems modeling using a comprehensive viewpoint‐based SysML profile.Journal of Software: Evolution and Process,30(3), e1878. (Open Access)
• With software available at: https://github.com/AMADEOSConceptualModel/SysMLProfileAndApplication
• Puthuparambil, A. B., Brancati, F., Bondavalli, A., & Ceccarelli, A. (2022). SYSML-UML like modeling environment based on Google Blockly Customization. InCertifications of Critical Systems - The CECRIS Experience(pp. 65-79). River Publishers. (Open Access)
• With software available at: https://resilblockly.resiltech.com:8407/#/

Additional recommendations will be made during the lectures. Slides, web-based sources, and links to download the relevant tools will be made available to the students during the course.