The fall semester of the very special academic year 2020/2021 is over. Most of the students following the Master of Software Engineering program at the University of Amsterdam have just completed my course Embedded Software and Systems (ESS). The ESS course had changed in a three important ways this year.
Firstly, a generic lecture about Petri Nets was changed to a series about two lectures, explaining how Petri Nets can be used to model and analyze software interfaces and components. Part of the material for this course was reused from the course Modelling and Analysis of Component-based Systems (MOANA-CBS), developed together with Thales targeting an industrial audience. These new lectures also prime students nicely for a lecture about the DYNAMICS project, a research collaboration between ESI and Thales. This allows me to show how these models and analyses can be used in practice to address problems related to software evolution by detecting incompatibilities and generating adapters when updating software interfaces. A generic lecture about the data-flow model of computation was removed to create room for this new material, but I am happy to teach fewer modelling formalisms and have more time to go in depth and show how they can be used to solve industrial problems. A nice result of this change to the course is that three master students have accepted thesis projects in the area of modelling and analysis of software components and interfaces in collaboration with ESI under the supervision of myself and my colleague Debjyoti Bera.
Secondly, the course project was redeveloped this year. Previously, students used Mathworks Stateflow to program Lego Mindstorm EV3 rovers to follow a line, avoid obstacles, and count objects. However, this project felt a bit too much like a toy and there were technical problems with both rovers and tools that were hard to overcome and limited the education experience. In particular, it was not easily possible to see or influence how code was generated for the Lego Mindstorm robots, which felt like a missed opportunity when teaching model-based engineering.
Two bachelor students did their theses in spring to evaluate the suitability of using the TurtleBot3 Burger robot, both in reality and in simulation using Gazebo, in the course. In addition, Stateflow was exchanged for Yakindu Statechart Tools, which is easier to use and gives us the flexibility we need in code generation. The new application developed in the project is to use Yakindu to program the TurtleBot to autonomously drive through a maze and map it.
Lastly, the COVID-19 pandemic required the entire course to be taught online. As a result, used a blended learning approach and prerecorded the lectures so that the students could watch them when they wanted to. Online interactive sessions were added to the course where the students could ask questions about the lectures, and participate in quizzes and group discussions. Online teaching meant that the students did not have access to the four physical TurtleBots that we had purchased. Luckily, the newly developed course project could be done with simulations in Gazebo. Below is a demo from one of the groups that very successfully solved the assignment.
The ESS course is continuously evolving and maturing and next year will be no different. Most importantly, we hope that the pandemic will be over by then and that we can put our three physical TurtleBots to good use.
I attended the online edition of Software-Centric Systems Conference (SC2) today. Although I prefer the networking and social aspects of a physical conference, it was nice to enjoy these presentations from the comfort of my couch.
It was interesting to see that most of the conference presentations were related to domain-specific languages (DSLs) in one way or another. There were also presentations about model-based testing and digital twinning. I am not sure if model-based engineering was an intentional theme, or if this is just what is considered interesting in software-centric systems in the Netherlands for the moment. However, this suggests that the applied research into model-based design methodologies done by ESI (TNO) together with its industrial eco-system is highly relevant.
A highlight for myself was the two presentations about the Component Modelling and Analysis (ComMA) DSL. This is not only because it relates to my research on evolvable interfaces, but also because of the main message that the industry can achieve a lot through open innovation in areas that are not their core business, such as specification, verification, and evolution of software interfaces. Great news that ComMA will become open-source in 2021!
Two months ago, I mentioned that Bits & Chips had published an article about the ComMA (Component Modelling and Analysis) language and how it is being used in Philips and Thales to address challenges related to integration and evolution. The latter part, about semi-automatic detection and correction of interface incompatibilities as interfaces evolve is the topic of the DYNAMICS project, a research project between ESI (TNO) and Thales. This joint story, where two companies from different domains together presented their challenges and how it was addressed by technology developed by ESI was much appreciated by Bits & Chips and was invited as a keynote at the Software-Centric Systems Conference (SC2), which takes place on Thursday November 5. If you are interested in hearing this keynote, please register for the event. All presentations are also available on-demand after the event in case you cannot attend in real time.
In this short two minute presentation, I introduce myself and my fundamental and academic research into design methodologies for cyber-physical systems. I sketch a high-level view of the problem and outline a direction based on model-based engineering in which my previous work into domain-specific languages and analysis non-functional behavior fits. For a more elaborate description of my research, please have a look at my research page.
A course called “Modelling and Analysis of Component-based Systems” (MOANA-CBS) is being developed in collaboration with Thales as a part of the DYNAMICS project. The course addresses the challenge of overseeing the explosion of possible interactions between asynchronously communicating components in component-based systems. Some of these interactions may be undesirable and leave systems prone to deadlock, livelock, race conditions, and buffer overflows, reducing software quality. The course participants in the course learn how to mitigate this problem by modelling the behavior of components and interfaces using Petri Nets, a well-known formalism suitable for describing asynchronously communicating systems. Theory is linked to practice through demonstrations of relevant examples using the ComMA tool. Using properties and analysis methods for Petri Nets, they learn how to identify patterns in component and interface design that may cause the aforementioned problems, as well as design guidelines for how to avoid them. The course is taught using a combination of lectures, assignments, demonstrations, discussions, and reflection.
We piloted parts of the course at Van der Valk Hotel in Arnhem on October 7 and 8, attended by 12 software architects from Thales and Luminis. The course was positioned as a part of their Accelerate program, which aims to accelerate young architects from the two companies into a more senior role. We felt that the delivery of the course went well and evaluations from the participants suggests it was well-received. The evaluation of this pilot also highlighted some further points for improvement that will be considered going forward.
Bits & Chips just published an article about ComMA (Component Modelling and Analysis). ComMA addresses key design and verification challenges for complex systems comprising many components developed by different parties, challenges that are frequently encountered in the high-tech industry across application domains. The challenges are tackled by allowing structure and behavior of component interfaces to be formally specified using a set of domain-specific languages. From this specification, a number of artifacts are automatically generated, including system tests, run-time monitors that detect protocol violations, performance metrics, and documentation. Together, these artifacts reduce the time to design, integrate, and evolve complex high-tech systems, allowing the next generation of these systems to be developed faster and with higher quality.
ComMA was developed by ESI (TNO) in applied research projects with Philips. Successfully proving the approach in an industrial context at Philips has sparked interest from other companies, including Thermo Fisher Scientific, Thales, and Kulicke & Soffa. This eco-system of high-tech companies is expected to increase further as the ComMA tooling becomes open source as part of the Eclipse Foundation.
The article also mentions the applied research project DYNAMICS, for which I am the technical lead. Here, ESI and Thales have been looking at challenges and opportunities related to the evolution of interfaces. The strong point of interfaces is that they abstract from the component providing a particular functionality, allowing it to be changed or even replaced without compromising the overall functionality of the system. However, eventually the interfaces themselves need to be updated to prevent technical debt, and at that point all components relying on that interface are affected simultaneously. In the DYNAMICS project, we study how to automatically detect whether a change to the protocol of an interface is backwards compatible and if this is not the case, semi-automatically generate adapters that bridge the differences with previous versions. The benefit of this approach is that it reduces the time and cost of interface updates, allowing them to evolve faster and avoid creative workarounds that ultimately lead to unreliable systems and lower software quality. If you are interested in reading more about this work and how it leverages ComMA and Petri Net technology to achieve this, read this overview paper from last year.
Mohammed (Mo) Diallo just defended his bachelor thesis entitled “Towards the Scalability of Detecting and Correcting Incompatible Service Interfaces“. This work is carried out in the context of a project between ESI (TNO) and Thales that developed a five-step methodology for automatic detection and correction of behavioral incompatibilities resulting from evolving software interfaces (see paper for more details). Mo’s thesis provides a starting point for evaluating the scalability of the proposed methodology. An essential ingredient towards this is the ability to synthetically generate interfaces of various complexity. The thesis has two main contributions: 1) a notion of interface complexity in terms of inputs, outputs and non-determinism is defined and the relation between these parameters is studied, and 2) the methodology for a ComMA interface generator using user-supplied complexity parameters, and its implementation in a supporting tool, is introduced.
I would like to thank Mo for the excellent work he delivered in this thesis, and I am happy that he will continue working over summer to extend it.
During the past two years, I have been involved with setting up the Partnership Program Mastering Complexity (MasCot), funded NWO Domain Applied and Engineering Sciences together with ESI (TNO). After a long process of defining the key topics, writing the call, and aligning with applicants, four innovative research projects have finally been granted, allocating three million euros to research on software restructuring, testing, scheduling and design of cyber-physical systems. Congratulations to Andy Pimentel,Twan Basten, Jan Tretmans, Eelco Visser, and their collaborators for the accepted projects. I am looking forward to seeing the results!
The press release announcing my appointment as Professor at the University of Amsterdam is finally ready. Time to make them and ESI (TNO) proud!
The Chair of Design Methodologies for Cyber-Physical Systems focuses on two research areas.The first area considers design methodologies for cyber-physical systems in which abstraction, provided by models used for specification, analysis, simulation, or synthesis, play an essential role. While this area applies to cyber-physical systems in general, the second area focuses on design aspects of real-time systems. Together, these two areas capture much of my existing work in both academic (TU/e, CTU Prague, CISTER) and applied research (ESI) in different application domains and industries in which I have worked, e.g. avionics (Airbus), consumer electronics (Philips & NXP), and defense (Thales). They are also broad enough to sustain a long-term effort towards managing complexity of cyber-physical systems. For more information about the research, click the ‘Research‘ button in the menu at the top of the page.
My first mission will involve developing and teaching a course on Embedded Software and Systems, a course that is extremely relevant to our work at ESI. The course is primarily aimed at students following the Master in Software Engineering and teaches the fundamentals of embedded system development. This includes modelling systems using StateCharts, Petri Nets, Data-flow graphs, and Domain-Specific Languages, embedded hardware, functional and timing verification, and design-space exploration. I will also explain the industrial reality behind some of these aspects by drawing on my experience from projects at ESI.
During the course, the students will get practical experience with model-based engineering as they work in groups to program a LEGO Mindstorm Rover using Stateflow to autonomously follow a path, while avoiding obstacles. From this batch of students, I am hoping to find some promising ones that can help us make the next innovative steps in model-based engineering for complex cyber-physical systems for their thesis project.
After six days in Munich I have now left the MODELS 2019 conference. It has been an intense couple of days with three days of workshops and tutorials, and three days of main conference. Both the technical and social aspects of the conference were exceptionally well-organized, so kudos to the men and women who worked hard to make that happen.
2. A tutorial on StateCharts that improved my understanding of a model-of-computation I will be teaching at the University of Amsterdam in the near future. Thanks to Simon van Mierlo, Hans Vangheluwe, and Axel Terfloth for organizing this tutorial and for sharing their excellent material.
3. Meeting and discussing with representatives from BMW, Daimler, MAN, Continental, TTTech, and other automotive companies and hear more about automotive trends towards centralization of computation, first through domain controllers and then further towards integration of domains in automotive “supercomputers”. It was also interesting to see that the automotive industry is showing interest in service-oriented architectures as a paradigm for their platforms. In fact, a paper entitled “Model-Based Resource Analysis and Synthesis of Service-Oriented Automotive Software Architectures” from BMW got the Best Paper Award on the Practice and Innovation track for work in this direction. This confirms our belief that our current applied research on service-oriented architectures in the defense domain can be generalized to other domains.
4. Meeting and talking to people from both Flanders Make and CETIC, which are the Flemish and Wallonian equivalents of ESI (TNO). It was interesting to talk to them and learn about how what we do is similar and different, both in terms of technical scope and business models.
I hope to return to the MODELS conference again next year to present more of our work and have another opportunity to discuss with and learn from top academics and industrialists in the area of model-based engineering.