Tag: defense

Reflections on a PhD Defense: Real-Time Guarantees in the Edge–Cloud Continuum

Posted on by Benny Akesson

Today, I served on the PhD committee of Nasim Samimi, who defended her dissertation titled “Edge-Cloud-Assisted Real-Time Cyber-Physical Systems.” This work addresses the challenge of providing predictable real-time guarantees for cyber-physical systems deployed across the edge–cloud continuum. As CPS increasingly rely on distributed, shared, and dynamic infrastructures, traditional design-time schedulability analysis becomes insufficient. The dissertation proposes a set of online admission control, scheduling, and orchestration techniques that provide per-job deadline guarantees and controlled service degradation under bursty workloads. The main contributions span formal job-level admission control for multicore servers, weakly-hard real-time guarantees using (M,K)-firmness, and practical deployment mechanisms for real-time workloads in Kubernetes-based edge–cloud platforms. Together, these contributions aim to bridge the gap between real-time theory and modern cloud-native practice.

I very much enjoyed reading this dissertation, as it tackles an important problem at the intersection of real-time systems, cyber-physical systems, and edge–cloud computing. I particularly appreciate the combination of solid theoretical foundations in the early chapters with increasingly practical contributions in the later chapters. A great example of this is the KubeDeadline technology, which extends Kubernetes to schedule Linux containers according to the well-known SCHED_DEADLINE policy and guarantee them a portion of CPU bandwidth with bounded latency. This work successfully translates classic real-time scheduling concepts into modern edge-cloud software architectures.

The defense went well, and shortly after the beadle pronounced the end of the defense (“Hora est!”), Nasim became Dr. Samimi. Congratulations on this achievement! It was a pleasure to serve on this committee, and I wish Nasim all the best in her future career.

Optimizing Efficiency and Performance: PhD Thesis Defense on Energy- and Time-aware Scheduling for High-Performance Embedded Systems

Posted on by Benny Akesson

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!

Hazem Ali Defends Dissertation

Posted on by Benny Akesson

Today, Hazem Ali successfully defended his PhD dissertation entitled "Integrating Dataflow and Non-Dataflow Real-time Application Models on Multi-core Platforms" and became a doctor. The main contribution of the thesis is a design flow that integrates applications specified using two different application models, data-flow graphs and periodic real-time task sets, on a shared NoC-based multi-core platform. The committee recognized that the work was building bridges between two different communities in the world of real-time systems and that it was nice that the publications from the PhD work have been nicely integrated into a single design flow.

For those of you that are interested in a short summary of this work, please refer to his publication "Combining Dataflow Applications and Real-time Task Sets on Multi-core Platforms" accepted at the 2017 Workshop on Software and Compilers for Embedded Systems (SCOPES). Lastly, we wish Hazem the best of luck in his future career.