Cross-layer design of reconfigurable cyber-physical systems

Procedia Computer Science, 2017

2016 2nd International Workshop on Modelling, Analysis, and Control of Complex CPS (CPS Data), 2016

We describe INTO-CPS, a project that aims to realise the goal of integrated tool chains for the collaborative and multidisciplinary engineering of dependable Cyber-Physical Systems (CPSs). Challenges facing model-based CPS engineering are described, focussing on the semantic diversity of models, management of the large space of models and artefacts produced in CPS engineering, and the need to evaluate effectiveness in industrial settings. We outline the approach taken to each of these issues, particularly on the use of semantically integrated multi-models, links to architectural modelling, code generation and testing, and evaluation via industry-led studies. We describe progress on the development of a prototype tool chain from baseline tools, and discuss ongoing challenges and open research questions in this area.

Proceedings of the 15th ACM SIGSOFT symposium on Component Based Software Engineering - CBSE '12, 2012

Cyber Physical Systems (CPS) offer new ways for people to interact with computing systems: every thing now integrates computing power that can be leveraged to provide safety, assistance, guidance or simply comfort to users. CPS are long living and pervasive systems that intensively rely on microcontrollers and low power CPUs, integrated into buildings (e.g. automation to improve comfort and energy optimization) or cars (e.g. advanced safety features involving car-to-car communication to avoid collisions). CPS operate in volatile environments where nodes should cooperate in opportunistic ways and dynamically adapt to their context. This paper presents μ-Kevoree, the projection of Kevoree (a component model based on models@runtime) to microcontrollers. μ-Kevoree pushes dynamicity and elasticity concerns directly into resource-constrained devices. Its evaluation regarding key criteria in the embedded domain (memory usage, reliability and performance) shows that, despite a contained overhead, μ-Kevoree provides the advantages of a dynamically reconfigurable component-based model (safe, fine-grained, and efficient reconfiguration) compared to traditional techniques for dynamic firmware upgrades.

In the 'classical' engineering process of embedded systems, models are most commonly used to support the early definition of the system (or parts thereof) or the environment. However, with the move from (complex) embedded systems to cyber-physical systems (CPS), we are experiencing a paradigmshift. In contrast to traditional embedded systems, CPS are driven by three additional dimensions of complexity: The 'cross'-dimension, with issues like cross-application domains, cross-technologies, crossorganizations, etc; the 'self'-dimension, with issues like self-monitoring, self-adapting, self-optimizing, etc.; and the 'live'-dimension, with issues like liveconfiguration, live-update, live-enhancement, etc. Due to the necessary shift from the 'classical' development process in dedicated application domains with a clear distinction between Design/Implementation and Maintenance/Operation to the continuous development cycle merging these phases as well as roles like developer/operator/user, also the role of models in CPS requires a rethinking. In this contribution, we sketch how the model-based approach with construction, analysis and synthesis of models has to be adapted to support the engineering of cyber-physical systems, using the domain of smart energy systems for illustration.

Lecture Notes in Computer Science, 2012

Cyber Physical Systems involve the use of different computing, communication and control technologies and require satisfying simultaneously several restrictive constraints. One characteristic of CPS is that there is a constant evolution of technologies and tools that help designers to design this kind of systems. Due to its complexity, middleware architectures are frequently used to implement CPS. Most of these middleware architectures tend to use models of the software entities of the system. However, quite often, they do not consider the infrastructure (hardware and network) over which these systems are executed even though this is a key issue for these systems. In addition, frequently, it is necessary to make some composition and reconfiguration decisions at run-time over the current status of the infrastructure. This work proposes a model developed within the iLAND project that represents the static and operational status of the CPS infrastructure.

SIMULATION, 2011

Advanced mechatronic systems have to integrate existing technologies from mechanical, electrical and software engineering. They must be able to adapt their structure and behavior at runtime by reconfiguration to react flexibly to changes in the environment. Therefore, a tight integration of structural and behavioral models of the different domains is required. This integration results in complex reconfigurable hybrid systems, the execution logic of which cannot be addressed directly with existing standard modeling, simulation, and code-generation techniques. We present in this paper how our component-based approach for reconfigurable mechatronic systems, MECHATRONIC UML, efficiently handles the complex interplay of discrete behavior and continuous behavior in a modular manner. In addition, its extension to even more flexible reconfiguration cases is presented.

IFIP Advances in Information and Communication Technology, 2016

Cyber-Physical Systems are present in many industries such as aerospace, automotive, health-care and transportation, and over time they have become critical and require high levels of resiliency and fault tolerance. Often they are implemented on reconfigurable logic due to IP design reutilisation, high-performance, and lowcost. Nevertheless, the continuous technology shrinking and the increasing demand for systems that operate under different power profiles with high-performance has led to implementations operating below the maximum performance offered by a particular technology. Design tools are conservative in the estimation of the maximum performance that can be achieved by a design when placed on a device, accounting for any variability in the fabrication process of the device. This work takes a new view on the performance improvement of circuit designs by pushing them into the error prone regime, as defined by the synthesis tools, and by investigating methodologies that reduce the impact of timing errors at the output of the system. In this work two novel error reduction techniques are proposed to address this problem. One is based on reduced-precision redundancy and the other on an error optimisation framework that uses information from a prior characterisation of the device. Both of these methods allow to achieve graceful degradation in performance whilst variation increases.

VLSI Design, 2000

Several classes of modern applications demand very high performance from systems with minimal resources. These applications must also be flexible to operate in a rapidly changing environment. Achieving high performance from limited resources demands application-specific architectures, while flexibility requires architectural adaptation capabilities. Reconfigurable computing devices promise to meet both needs. While these devices are currently available, the issue of how to design these systems is unresolved. This paper describes an environment for design capture, analysis and synthesis of dynamically adaptive computing applications. The representation methodology is captured in a Domain-Specific, Model-Integrated Computing framework. Formal analysis tools are integrated into the design flow to analyze the design space to produce a constrained set of solutions. HW/SW Co-simulations verify the function of the system prior to implementation. Finally, a set of hardware and software subsystems are synthesized to implement the multi-modal, dynamically adaptive application. The application executes under a runtime environment, which supports common execution semantics across software and hardware. An application example is presented.