Benny Akesson

Senior Research Fellow @ TNO-ESI | Endowed Professor @ University of Amsterdam

Reflections on RTAS 2025 from the General Chair

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It has been a pleasure to serve as the General Chair of the 31st IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2025). RTAS is a top-tier conference on real-time systems that is a part of the CPS-IoT Week. This year, CPS-IoT week was hosted at UC Irvine, USA, and it was one of the most well-attended instances so far with over 550 registrations from all over the world.

Here are some personal highlights:

  • Keynote: “Trusted AI on Mars” by Dr. Steve Chien: This keynote discussed the challenge of controlling the Perseverance rover on Mars. The original planner was time-triggered and struggled to efficiently adapt to unexpected changes, e.g. in temperature and battery state. The core of the presentation covered the design, analysis, prototyping and testing of a new AI-based Onboard Planner that was deployed in October 2023. This planner enabled the schedule to be revised on average 16 times per day to manage resources, such as energy, more efficiently and maximize the scientific operations conducted by the rover. This presentation was very interesting to the real-time systems community as it focused on planning inside a heavily resource-constrained cyber-physical system in a dynamic environment far away from earth. It was interesting to hear the challenges of getting new technology adopted in such a critical system, where the cost of verification and validation is a key driver for decision-making.
  • Inaugural CPS-IoT Debate: We have all attended bland panel discussions at conferences. This was different, as it had the format of an Oxford debate and discussed whether the inherent complexity of modern engineering challenges renders exhaustive mathematical analysis overkill, and that an iterative, adaptive design approach should be prioritized—even for life-critical systems. The format, the existential nature of this question for our community, and the excellent choice of the debate team resulted in an engaging session with high audience participation that sparked conversations throughout the day. I strongly encourage other conferences to try out this format.
  • RTAS Technical Sessions: The technical sessions of RTAS are always of high quality and interesting. I particularly enjoy the papers that help bring theory into practice. Here are a few papers that stood out to me:
    • LiME: The Linux Real-Time Task Model Extractor by Bjorn Brandenburg et al. describes a tool to extract real-time task models from real-time threads in a Linux environment.  LiME runs on unmodified Linux kernels and requires neither knowledge of real-time theory nor familiarity with Linux internals to be used effectively. Such a tool can significantly reduce the engineering, modeling, and analysis effort required to develop real-time systems whose timing behavior can be formally verified.
    • Reconciling ROS 2 with Classical Real-Time Scheduling of Periodic Tasks by Harun Teper et al. explains how minor changes to the event executor of ROS2 makes a large body of research results from classical real-time scheduling theory directly applicable to ROS 2. This enables analytical bounds on the worst-case response time and the end-to-end latency, outperforming bounds for the default ROS 2 executor in many scenarios.
    • CROS-RT: Cross-Layer Priority Scheduling for Predictable Inter-Process Communication in ROS 2 by Kim et al., which won the Best Paper Award, addresses the challenge of providing real-time guarantees in ROS2 due to unpredictable delays and priority inversions across ROS 2’s multi-layered communication architecture. They present a cross-layer scheduler explicitly designed to tackle the unpredictability in ROS 2 inter-process communication that has been implemented and evaluated on the current stable release of ROS 2.

These works all make significant strides in bringing theory to practice. Just imagine what happens if you combine them all!

All in all, it was a very successful event thanks to the excellent work done by Program Chair Tam Chantem, Program Co-chair Geoffrey Nelissen, the General Co-chairs of CPS-IoT Week Mohammad Al Faruque and Yasser Shoukry, Local Arrangement Chairs Fadi Kurdahi and Halle Gonzales, and many others involved in the organization. Of course, RTAS would not have been possible without the many authors who submitted their work and the members of the TPC who took the time to read the submissions and provide high-quality reviews.

 

Highlights from the RTAS Awards Ceremony

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The Award Ceremony of the 31st IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS) has concluded, and it is our pleasure to announce the highlights of this year’s awards.

The RTAS 2025 Technical Program Committee nominated four papers for awards, evaluating them based on novelty, presentation, applicability to real-world applications/systems, and relevance and completeness of experimental evidence. The four papers were selected as Outstanding Papers and candidates for the Best (Student) Paper Award.

Best Paper Award
CROS-RT: Cross-Layer Priority Scheduling for Predictable Inter-Process Communication in ROS 2
Authors: Sohyun Kim, Juho Song, Kilho Lee, Sangeun Oh, and Hoon Sung Chwa

This paper tackles the challenges of achieving real-time guarantees in ROS2 due to unpredictable delays and priority inversions. CROS-RT, a cross-layer scheduler, ensures consistent priority-based scheduling across application, middleware, and kernel layers. Experiments show that CROS-RT significantly improves communication predictability, reducing the worst-case response time compared to baseline ROS2. The Best Paper Award committee was impressed by this paper’s practical significance and immediate, as well as long-term, impact on the field.

Best Student Paper Award
A Unified Framework for Quantitative Cache Analysis
Authors: Sophie Kahlen and Jan Reineke

This work unifies two approaches to cache analysis for non-LRU policies. It is applicable to microarchitectures with timing anomalies and enhances WCET analysis using existing persistence analyses for LRU. Experiments demonstrate that the precision of cache analysis for FIFO and MRU is comparable to that of LRU. The Best Paper Award committee viewed this paper as an excellent example of a well-integrated blend of theoretical results and implementation efforts, which embody the spirit of RTAS.

The Best Reviewer Committee evaluated six nominated reviews/reviewers based on criteria like review quality, completeness, and helpfulness to the authors. Four reviewers were recognized as Outstanding Reviewers and candidates for the Best Reviewer Award.

Best Reviewer Award
Zoe Stephenson, Rapita Systems, UK

RTAS is grateful to all members of the Technical Program Committee who volunteer their time to review submitted papers. It is particularly rewarding when industry members contribute to the conference and stand out in terms of reviewing excellence, both in thorough reviews and active participation in discussions. Thank you, Zoë!

We want to thank the members of the Award Committees and congratulate all award recipients on their achievements and thank you for your contributions to another successful RTAS!

Benny Akesson, General Chair
Tam Chantem, Program Chair
Geoffrey Nelissen, Vice Program Chair

 

 

New Methodology for Efficient Design Space Exploration in Next-Gen Cyber-Physical Systems

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I’m excited to share that our journal article “CompDSE: A Methodology for Design Space Exploration of Computing Subsystems within Complex Cyber-Physical Systems” has been accepted for publication in IET Cyber-Physical Systems: Theory and Applications! The article, first-authored by Faezeh Sadat Saadatmand, outlines the model-based Design Space Exploration (DSE) approach we used in the DSE2.0 project. This project is a collaboration between Leiden University, the University of Amsterdam, and ASML, and is co-funded by NWO and TNO-ESI.

Our work addresses the need for efficient DSE techniques to evaluate potential design decisions and their impact on non-functional aspects like performance, reliability, and energy consumption in next-gen complex distributed cyber-physical systems (dCPS).

In the article, we introduce CompDSE, a methodology designed to facilitate the DSE of complex dCPS, with a focus on the computing subsystems. CompDSE uses abstract models of the application workload, computing hardware platform, and workload-to-platform mapping, all automatically derived from runtime trace data. These models are integrated into a discrete event simulation environment to explore various design points.

We demonstrate the effectiveness of our methodology through a case study on the ASML Twinscan lithography machine, a complex industrial dCPS. The results show potential performance enhancements by optimizing computing subsystems while considering physical constraints. Each design point evaluation takes less than a minute, highlighting CompDSE’s efficiency and scalability in tackling complex dCPS with large design spaces.

Highlights from TNO-ESI at ICT.OPEN 2025

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NWO ICT.OPEN 2025 took place in the Jaarbeurs in Utrecht on April 15 and 16. In retrospect, I think it was the best ICT.OPEN I have visited so far. It was also the most popular edition in modern times, with over 500 registered participants and another 200 people wanting to register, but who could not be accommodated. It was particularly nice to see that systems research is now well represented at the conference again, thanks to the CompSys community and organizations like TNO. TNO was highly visible at the event this year with representation from several research groups within the unit ICT, Strategy and Policy. Below are some highlights focusing on the involvement from my dear group TNO-ESI:

  • Keynote: I gave a keynote titled “Engineering the Future: Addressing System Complexity in High-Tech Equipment”, which described the challenge of increasing system complexity in high-tech equipment and how TNO-ESI addresses this challenge in an open innovation ecosystem by developing engineering methodologies based on model-based engineering, formal methods, and artificial intelligence. Two examples were given of such methodologies, ComMA and Renaissance, highlighting the collaborations in the innovation chain and describing the industry impact.  Immediately after the keynote, I also participated in an NWO Panel session about partnerships in ICT Research, where challenges and best practices for research collaborations were discussed among the panelists and with the audience.
  • Mastering Complexity Track: Rosilde Corvino and Nan Yang co-chaired the track “Mastering Complexity for Cyber-Physical Systems”, which featured three presentations: one invited industry talk and two peer-reviewed research contributions. The invited presentation was delivered by Alok Lele, Project Manager at ASML Software Research. He shared insightful perspectives on leveraging Generative AI to modernize the software of ASML systems. His concept of continuous and iterative micro-modernization sparked an engaging discussion among the audience. In addition, PhD candidates Faezeh Sadat Saadatmand and Ameneh Naghdi Pour presented their research on design-space exploration and system diagnosis, respectively. The session was interactive and discussed emerging methodologies and challenges in managing complexity in cyber-physical systems.
  • Research results: Emile van Gerwen and Micha Lipplaa demonstrated how using chain-of-thought prompting with a Large Language Model (LLM) in combination with semantic search helps Philips Healthcare in their risk assessment of incoming complaints. Their work concluded that compared to both keyword search and semantic search without an LLM knowledge extraction pre-processing step, a combined approach clearly shows the best results.

I would like to thank all organizers for a lovely event, particularly the Program Co-chairs Mitra Nasri and Vadim Zaytsev for putting together a fantastic program.

MOANA-CBS Milestone at Thales

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It is a fantastic feeling when research results in industry impact! We recently celebrated that our course Modelling and Analysis of Component-based Systems (MOANA-CBS) was given for the 10th time at Thales. We celebrated this milestone with an appropriately themed cake. In total, about 100 systems and software engineers have now been trained in specification and verification of software interfaces using Eclipse CommaSuite. Hats of to our Thales trainers, Jeroen Kouwer and Mark Horsthuis, who are giving the trainings. The word on the street is that seats for the course are still filling up quickly and that more instances of the course are to be expected in the future.

It is not only engineers at Thales that benefit from MOANA-CBS. We also made an academic version of the course that focuses on modelling and verification of software interfaces using Petri nets, allowing students to learn some basics of model-based engineering using examples from the world of systems and software engineering. This material is given as a part of my course Model-based Design of Cyber-physical Systems, which is given to approximately 80 software engineers at University of Amsterdam every year. By now, more than 300 students have learned from this material.

The MOANA-CBS course is a result from the DYNAMICS project, a public-private collaboration between Thales and TNO-ESI that ran between 2019-2021. For more information about the the project and a demo, please read more here.

Paper on Energy Labeling of Digital Services Accepted at CCGRID 2025

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Congratulations to Saeedeh Baneshi for having her paper, “Empowering Sustainability: Energy Labeling of Digital Services Using Simulation” accepted at the 25th IEEE International Symposium on Cluster, Cloud, and Internet Computing (CCGRID).

This work addresses the challenge of creating awareness about the energy consumption of digital services distributed across the compute continuum in an understandable and actionable way. The paper proposes the first operational energy labeling method for digital services in this context. This approach enables stakeholders—including cloud and network providers, application developers, researchers, and end-users of digital services—to better understand and improve the energy efficiency of their applications. Focusing on a video surveillance application and utilizing the enhanced iFogSim framework, the paper proposes an energy labeling scheme and demonstrates its merits through extensive scenario analysis and simulation. It also discusses how this approach can help reduce energy consumption and/or improve performance, without modifying the application’s functional parameters or system architecture.

Congratulations on the acceptance of your paper, Saeedeh. Enjoy the conference in Tromsø, Norway!

 

 

 

William Ford Successfully Defends Master Thesis on Network Delay Models for dCPS

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On Wednesday, William Ford, a master student from VU/UvA defended his master thesis “Network Delay Model Creation and Validation for Design Space Exploration of Distributed Cyber-Physical Systems“. This thesis was executed in the context of the MasCot project DSE2.0 and was supervised by Benny and Faezeh Sadat Saadatmand, PhD student at Leiden University.

William’s thesis focuses on improving the development process of complex distributed cyber-physical systems (dCPS), such as the equipment developed by high-tech companies like ASML, Canon Production Printing, and Philips. Building physical prototypes for these systems is complex and costly, so the thesis explores automated and scalable model-based Design Space Exploration (DSE) as a solution. The research addresses the challenge of modeling network delays in dCPS, aiming to create models that balance speed and accuracy for DSE purposes. The methodology includes formalizing network topology and traffic concepts, resulting in an open-source framework for synthetic network generation called GeNSim. Three analytical network delay models—Constant Delay, Constant Bandwidth, and Latency-Rate, and a simulation-based approach using the INET framework—are proposed and evaluated synthetic networks and an industry case study at ASML. The findings reveal that each model has its strengths and weaknesses, with no single model meeting all requirements perfectly. Therefore, a multi-step modeling approach is suggested to leverage the strengths and mitigate the weaknesses of the different models.

William confidently presented his thesis. In particular, the committee was very happy with the Q&A session after the presentation, which resulted in a lively back and forth with interesting questions and answers. Having defended his thesis, William can now apply for his diploma and graduate. We thank William for his contributions to the DSE2.0 research and wish him all the best with his future career.

Final MasCot Program Day Highlights Results, Lessons Learned, and Future Collaborations

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I had a fantastic time hosting the fourth Mastering Complexity (MasCot) Program Day on October 9 at TU Delft. MasCot, a €3M academic program co-funded by TNO-ESI and NWO, addresses the pressing need for new advanced engineering methodologies through four projects covering essential topics, such as design space exploration during early system design, scheduling, verification, and restructuring of evolving software.

The day started with an update from the four academic projects in the program, focusing on updates and new results from the last year. It was interesting to hear a mix of positive results, e.g. new scheduling methods that outperform previous approaches, as well as negative results, a counter-example that demonstrated that further attempts at proving a particular theory were not worthwhile.

In the afternoon, TNO-ESI and industry partners from the projects shared their user stories, in which they reflected on the value of the program and the knowledge and proof-of-concept implementations developed in it. The user stories were positive and included examples of planned and ongoing technology transfer from the projects.

There were also breakout sessions where TNO-ESI, academic staff, industry representatives, and PhD students separately discussed what went well during the organization and execution of the program, and what should be done differently in the future. This feedback will be consolidated in a document describing the lessons learned from the MasCot Program, which will be used as a basis to refining the method for academic collaborations at TNO-ESI. It was clear from the feedback from all groups that everyone appreciated the program and how TNO-ESI brought academia and industry together to solve relevant problems. A main challenge for the future is to better align stakeholders from industry and academia and their different goals, environments, and timelines.

The day program was concluded with an interactive session, structured around our PMCs, where participants worked together to identify interesting research challenges and hot research topics for future academic collaborations. What stood out in terms of challenges was a clear need to address testing and integration challenges, also in the context of microservices. When looking at hot research topics and technological opportunities … you guessed it … safe, explainable, responsible, … , AI for Systems Engineering!

The day concluded with a social program at Stadsbrouwerij De Koperen Kat with a short tour given by the owner and a BBQ buffet with beer tasting. That concluded the fourth, and last MasCot Program Day.

 

Master’s Thesis Explores User Behavior’s Impact on Digital Service Energy Consumption

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Just before the end of summer, Nsidibe Onoyom Bassey, master student at the Vrije Universiteit Amsterdam, has successfully defended her thesis “Impact of Users’ Behavior on Digital Service Energy Consumption“. Congratulations on the defense and completing your studies Nsidibe!

This work was supervised by Ana Lucia Varbanescu and myself in the context of our research project Energy Labels for Digital Services, which studies the energy consumption of applications distributed over the compute continuum. In particular, the research addresses the growing concerns over energy consumption in the ICT sector, which poses challenges to achieving net-zero emissions. While ICT solutions are often seen as efficient and low-cost, their energy impact is significant, particularly due to the high demand for digital services, such as online shopping. Energy consumption in the digital domain is largely driven by hardware, software, and infrastructure, but the role of user behavior in influencing this consumption is often overlooked. The thesis focuses on understanding how user behavior affects energy consumption in digital services, using a commonly used open-source online shop implemented as microservices as a case study. The energy consumption on both the client and server side is studied and experiments are conducted with different client browsers, user interactions, and number of users. Based on the experiments, an analytical model is proposed to estimate the energy impact of user behavior on the server side and recommendations are made to both users and developers for how to limit energy consumption.

Paper on Multi-Application Energy Analysis in Edge Computing Accepted at FMEC 2024

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Good news everyone! Our paper “Analysing Per-Application Energy Consumption in a Multi-Application Computing Continuum” was accepted at the 9th International Conference on Fog and Mobile Edge Computing (FMEC 2024). This paper was first-authored by Saeedeh Baneshi, a PhD student at the University of Amsterdam, and complements her earlier work “Estimating the Energy Consumption of Applications in the Computing Continuum with iFogSim“. Congratulations on another accepted paper Saeedeh!

The paper addresses the challenge of analyzing the energy consumption of applications distributed over edge devices and data centers in the compute continuum. The goal is to enable stakeholders, such as cloud providers, developers, users, and researchers, to improve energy efficiency, optimize resource usage, and reduce the environmental impact of such applications. To this end, the work proposes a fine-grained simulation approach for analyzing application energy behavior in edge/cloud environments, based on the iFogSim framework. The three main contributions of the work are: 1) An extension is proposed to iFogSim’s energy model to also consider the energy consumption of communication, 2) iFogSim’s reporting is improved to collect finer-grained data, an essential improvement for analysis of multi-application scenarios, and 3) The effectiveness of the approach is demonstrated by evaluating different multi-application scenarios and configurations for a distributed video surveillance application.