Yesterday, I participated in the PhD defense committee of Julius Röder, a PhD student in the Parallel Computing Systems group at the University of Amsterdam. The thesis “Energy- and Time-aware Scheduling for Heterogeneous High-Performance Embedded Systems” addresses the relevant problem of optimizing non-functional behavior, such as timing and energy consumption, of heterogeneous high-performance embedded systems. The goal of this optimization Is to reduce energy consumption, thereby also reducing carbon footprint and extending battery-life, as well as ensuring that real-time requirements of applications are satisfied, even at high resource utilizations. To this end, the thesis contributes a discussion on setups used for energy measurements, as well as experiments and a statistical analysis that demonstrate the Importance of sampling frequency on the accuracy of such measurements. The bulk of the thesis proposes heuristic algorithms, both conventional and based on reinforcement learning, for mapping and scheduling applications modelled as directed acyclic graphs (DAG) on heterogeneous platforms. The applications are assumed to be available In different versions, with different non-functional behavior, for the different types of processing elements In the heterogeneous architecture, which enables trade-offs between timing and energy. A key strength of the thesis is that theory is combined with a practical component; the scheduling algorithms are implemented and evaluated on a heterogeneous multi-core systems, where timing and energy behavior are carefully measured and analyzed.
In presence of family, friends, and colleagues, Julius confidently defended his PhD thesis and earned the right to call himself a doctor. Congratulations Julius with this great achievement!
Another literature review has been completed in the context of the DSE2.0 research project. William Ford completed his review entitled “Network Delay Model Creation and Validation for Design Space Exploration of Distributed Cyber-Physical Systems“.
Design-space exploration (DSE) in early phases of design of a distributed cyber-physical system (dCPS) requires models. In the DSE2.0 project, we are particularly interested in models that capture the timing behavior of hardware and software, allowing temporal system performance to be evaluated for different design points. One important part of the system to model is the network that connects the subsystems of the CPS. This study reviews previous work in the fields of analytical network modeling, network simulation, and network model validation. In addition, a recommended plan is presented to create and validate such a network model for the DSE2.0 project, based on this previous work. Two main directions are recommended at different levels of abstraction. For the lower level of abstraction, we will make a model using the existing INET framework that models each network element explicitly. At a higher level of abstraction, we will use a latency-rate server to capture the behavior of the network using only two parameters, latency and rate.
Having delivered his literature review. William has started his master project to pursue this research along these directions. The team looks forward to working with him.
I recently co-organized a Dutch Real-time Days event together with real-time systems researchers from TU/e and UT. The event was funded through a 4TU.NIRICT Call Community Funding and its goals were to:
1) share and develop new ideas for real-time systems research,
2) stimulate new collaborations, and
In addition to the four organizers from the Netherlands, Mitra Nasri (TU/e), Geoffrey Nelissen (TU/e), Kuan-Hsun Chen (UT), and myself, four well-established European researchers in the area of real-time systems were invited to the event. Everybody was invited to pitch their current work, ideas for future directions, and appropriate mechanisms to support collaborations. This was followed by brainstorming sessions were these ideas were creatively improved, as well as a working session where some of the ideas were discussed in more detail and made actionable. At the end of the first day, there was a lovely dinner at Restaurant Giornale in Eindhoven, providing further room for discussions and networking.
The outcome of the two days was a mix of technical ideas that can be pursued in future research papers or project proposals, and actions to shape direction of the academic real-time systems community and further increase its industrial relevance. For example, we agreed to propose that the Technical Community on Real-time Systems (TCRTS) adds an award for industry impact/technology transfer and propose a special issue on industry challenges/visions in the Journal of Real-time Systems.
The TNO-ESI Cloud Continuum workshop, an informal hybrid event that attracted just over twenty participants, took place at ESI on February 21. The goals of this workshop were to: 1) connect applied and academic researchers in the area of cloud continuum in the Netherlands, 2) disseminate research results from ongoing research projects, and 3) identify possibilities for collaboration. Benny Akesson, the organizer of the event, opened the workshop by presenting some drivers for cloud adoption/integration in the high-tech industry, as well as the work done by ESI in the ArchViews and TRANSACT projects related to performance observability. This was followed by four invited speakers from Eindhoven University of Technology and Vrije Universiteit Amsterdam. The topics of the presentations ranged from reference architectures for the cloud continuum, root-cause analysis in the continuum, modelling and calibration of cyber-physical systems deployed in the continuum, to performance variability of cloud/edge systems. All in all, it was a nice and successful event that showcased parts of the body of work currently going on in this exciting area. Thank you Matthijs Jansen, Jeroen Voeten, Mahtab Modaber, and Panagiotis Giannakopoulos for your presentations.
Our paper entitled “Thirteen Concepts to Play it Safe with the Cloud” has been accepted at IEEE International Systems Conference (SysCon), that will take place in Vancouver, Canada on April 17-20, 2023. The paper discusses how edge and cloud technologies has the potential to enhance safety-critical CPS, also in regulated environments. This is only possible when safety, performance, cyber security, and privacy of data are kept at the same level as in on-device only safety-critical CPS. To this end, this paper presents thirteen selected safety and performance concepts for distributed device-edge-cloud CPS solutions. This early result of the TRANSACT project aims to ensure needed end-to-end performance and safety levels from an end-user perspective, to extend edge and cloud benefits of more rapid innovation and inclusion of value-added services, also to safety-critical CPS.
Herman Kelder has joined the DSE2.0 research project as a master student. DSE2.0 is a project that aims to propose a methodology for design-space exploration of complex distributed cyber-physical systems, like lithography machines manufactured by ASML. One of the great challenges is to improve the scalability to handle the complexity of such systems, a challenge that needs to be addressed both in terms of how the system (performance) is modelled and evaluated (simulated) for a particular design point, as well as how design points to evaluate is being chosen. Hermans thesis will focus on how to improve the scalability of system-level simulation to allow more design points to be evaluated faster.
One of Herman’s first assignments was to put together a literature review on this topic. The literature review, entitled “Exploring Scalability in System-Level Simulation Environments for Distributed Cyber-Physical Systems“, investigates state-of-the-art scalability techniques for system-level simulation environments, i.e. Simulation Campaigns, Parallel Discrete Event Simulations (PDES), and Hardware Accelerators. The goal is to address the challenge of scalable Design Space Exploration (DSE) for dCPS, discussing such approaches’ characteristics, applications, advantages, and limitations. The conclusion recommends starting with simulation campaigns as those provide increased throughput, adapt to the number of tasks and resources, and are already implemented by many state-of-the-art simulators. Nevertheless, further research has to be conducted to define, implement, and test a sophisticated general workflow addressing the diverse sub-challenges of scaling system-level simulation environments for the exploration of industrial-size distributed Cyber-Physical Systems.
We look forward to working with Herman and seeing how his research develops along these directions.
I have had the honor to serve as the chair of RTSS@Work 2022, the open demo session organized as a part of the 43rd IEEE Real-Time Systems Symposium, held in Houston, Texas on December 6, 2022. The goal of RTSS@Work is to provide a platform for researchers to present prototypes, tools, simulators, and systems, which extend the state-of-the-art in Real-Time Technologies and Techniques. It augments the traditional forum by enabling presenters to demonstrate working systems, thereby allowing them to directly engage with the audience, generate interest in new research topics, and encourage wider adoption of common frameworks.
This year’s RTSS@Work was very special, as it was the first physical instance after years of virtual events due to the COVID pandemic. It was nice to meet each other again and to physically demonstrate and discuss the work we have done. While the COVID pandemic reduced the number of submissions in previous years, I am happy to announce that we had nine demo submissions this year, on par with the pre-pandemic era. The program committee, comprising seven researchers, selected eight demos to appear in the session. I would like to thank the program committee for accepting my invitation and for spending their time reviewing and selecting the demo abstracts. I would also like to thank the authors for submitting to RTSS@Work, for delivering the camera-ready abstracts on time, and for demonstrating their work at the conference.
The proceedings of RTSS@Work 2022 are now available online.
The 3rd Annual Program Day for the Mastering Complexity (MasCot) Partnership program took place on Wednesday October 19. This time, the event was hosted by the University of Amsterdam and was held in the Startup Village at Science Park. Approximately 40 participants from academia, industry, NWO, and TNO attended the event. After a brief introduction, project updates were given from the four academic projects in the program:
- Scheduling Adaptive Modular Flexible Manufacturing Systems (SAM-FMS)
- Programming and Validating Software Restructurings
- TiCToC – Testing in Times of Continuous Change
- Design Space Exploration 2.0: Towards Optimal Design of Complex, Distributed Cyber Physical Systems
This was followed by Q&A and a short interaction where participants tried to identify the general complexity management techniques used in the projects. In the afternoon, there were breakout sessions focusing on the way-of-working in MasCot projects, how to best involve and engage all stakeholders in the project: industry and academic partners, users, and ESI liaisons. This allowed the different projects to listen to how the others organized their work, e.g. in terms of regular meetings and working on industry location, during the first years and reflect on the best way-of-working to reach their goals for the next stage.
The event was followed by a social program with informal networking set to the tune of a boat ride with drinks on the beautiful canals of a sunny autumn-colored Amsterdam and a dinner at the restaurant In de Waag.
Software interfaces are key to realizing the benefits of component-based software architectures, yet specifying interfaces is difficult and may result in problems in the protocol specification itself, or in its interactions with clients. This problem is addressed through a six-step methodology for specification, verification, and adaptation of software interfaces. The methodology builds on the open-source tool Eclipse ComMASuite, developed by TNO-ESI partners in an open innovation eco-system. The specification and verification steps have been contributed back to the community and are supported by a two-day course named “Modelling and Analysis of Component-based Systems”, available from TNO-ESI in both an academic and industry version.
Please read my blog post that describes the methodology and demonstrates it step-by-step from a user perspective through a simple case study in a video.
I am pleased to announce that our position paper “Design Space Exploration for Distributed Cyber-Physical Systems: State-of-the-art, Challenges, and Directions” has been accepted for publication at the Euromicro Conference on Digital System Design (DSD). This is the first accepted paper from the DSE2.0 project, a collaboration between University of Amsterdam, Leiden University, and ASML. The project is a part of the Mastering Complexity (MasCot) partnership program funded by ESI.
The paper addresses the challenge of designing industrial cyber-physical systems (CPS), which are often complex, heterogeneous, and distributed computing systems that typically
integrate and interconnect a large number of hardware and software components. Producers of these distributed Cyber-Physical Systems (dCPS) require support for making (early) design decisions to avoid expensive and time consuming oversights. This calls for efficient and scalable system-level Design Space Exploration (DSE) methods for dCPS. In this position paper, we review the current state of the art in DSE, and argue that efficient and scalable DSE technology for dCPS is more or less non-existing and constitutes a largely unchartered research area. Moreover, we identify several research challenges that need to be addressed and discuss possible directions for targeting such DSE technology for dCPS.