Tag: simulation

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

Posted on by bennyakesson

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.

Scaling the Future: Master Thesis Defense on Scalability in Simulation Environments for Distributed Cyber-Physical Systems

Posted on by bennyakesson

Today, we celebrate that Herman Kelder successfully defended his master thesis “Scalability in System-Level Simulation Environments for Distributed Cyber-Physical Systems“. This work was carried out in the context of the DSE2.0 project, where we address the complex scientific challenges involved in performing design-space exploration (DSE) for complex distributed cyber-physical systems (dCPS), such as lithography machines. Three key challenges in this context are: 1) automatically modelling the application and platform based on data from the running system, 2) scalable search and pruning algorithms that help navigate large design spaces efficiently, and 3) scalable simulation environments that allow many design points to be efficiently evaluated concurrently.

Herman’s thesis addresses the last of these three challenges. To facilitate scalable and efficient DSE for dCPS, an evaluation environment is proposed, implemented, and evaluated. The research considers key design considerations for developing a distributed evaluation workflow that can dynamically be adapted to enable efficient and scalable exploration of the vast design space of complex, distributed cyber-physical systems. Evaluation of the proposed environment employs a set of system models, representing design points within a DSE process, to assess the solution and its behavior, performance, capability, and applicability in addressing the scalability challenge in the context of DSE for dCPS. During the evaluation, the performance and behavior are investigated in three areas: (i) Simulation Campaign, (ii) Task Management Configuration, and (iii) Parallel Discrete-Event Simulation (PDES). Throughout the evaluation, it is demonstrated that the proposed environment is capable of providing scalable and efficient evaluation of design points in the context of DSE for dCPS. Furthermore, the proposed solution enables designers and researchers to tailor it to their environment through dynamic complex workflows and interactions, workload-level and task-level parallelism, and simulator and compute environment agnosticism.

Herman executed his project meticulously and delivered excellent research results, both in terms of concepts and implementation. Thank you very much for your contributions Herman and we hope to work with you again at some point.

Literature Review on Scalable System-level Simulation

Posted on by bennyakesson

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.

Book Chapter Published by Elsevier

Posted on by bennyakesson

I am pleased to announce that our chapter “Reducing Design Time and Promoting Evolvability using Domain-specific Languages in an Industrial Context” has been accepted for publication in the Elsevier book “Model Management and Analytics for Large Scale Systems“.

This work is the result of an industrial ESI project addressing the need for new methodologies to reduce development time, simplify customization, and improve evolvability of complex software systems. The chapter explains how these challenges are addressed by an approach to model-based engineering (MBE) based on domain-specific languages (DSLs). However, applying the approach in industry has resulted in 5 technical research questions, namely how to: RQ1) achieve modularity and reuse in a DSL ecosystem, RQ2) achieve consistency between model and realizations, RQ3) manage an evolving DSL eco-system, RQ4) ensure model quality, RQ5) ensure quality of generated code. The five research questions are explored in the context of the published state-of-the-art, as well as practically investigated through a case study from the defense domain.