Periodic Reporting for period 3 - IMMORTAL (Integrated Modelling, Fault Management, Verification and Reliable Design Environment for Cyber-Physical Systems)
Reporting period: 2017-03-01 to 2018-02-28
Recently, the world has seen emerging Cyber-Physical System (CPS) modelling frameworks addressing various design aspects such as control, security, verification and validation. However, there have been no considerations for reliability and automated debug (i.e. design error localisation and correction) aspects. The main aim of IMMORTAL was to fill this gap by introducing reliable design and automated system debug into CPS modelling. To reach this aim, the project developed a cross-layer CPS model spanning analogue mixed-signal circuits, hardware architecture, firmware, operating system and application layers. In addition, a holistic fault model for representing fundamentally different error sources in CPSs (design bugs, wear-out and environmental effects) in a uniform manner was proposed. Moreover, IMMORTAL developed a fault management infrastructure on top of the reliable design framework that allows ultra-fast fault detection, isolation and recovery in the emerging many-core based CPS architectures that are expected to be increasingly adopted in the coming years.
As a result, the project served as an enabler for development of dependable CPSs with improved reliability and extended effective life-time, which is a particular concern in emerging nanoelectronics technologies that are becoming increasingly vulnerable to disturbances, ageing and process variations. The tool framework to developed within IMMORTAL was evaluated on a clearly specified real-world use-case of a satellite on-board-computer. However, the results are more general and applicable to many application domains, including avionics, automotive and telecommunication.
In fault management, early fault detection and fast recovery by implementing a cross-layer fault management approach was achieved. This enables a graceful degradation environment for the CPS, where the systems’ tolerance to faults and life-time is improved and costs for maintenance are significantly reduced.
Concerning automated debug, IMMORTAL developed verification engines for CPS and extended them by automated design error localisation and correction capabilities. Previously, solutions for automated debug in CPSs were missing. Yet, it has been shown by numerous studies that error localisation and correction in digital computing systems consume a major portion of the overall development effort. In CPSs, this problem is going to be even more severe due to the underlying complexity and heterogeneity.
1) Minimisation of the verification effort in CPSs by a factor of 2 by enabling automated debug (error localisation and correction) in such systems. Methods that rely on lightweight models for CPS will be developed therefore, improving the scalability.
2) Speeding up fault detection, isolation and recovery in CPSs by a factor of 6 by implementing a cross-layer approach, a holistic fault model and a new fault management architecture.
3) Graceful degradation: by resumption of correct operation with up to 80% of CPS network resources failed. To be achieved by development of network reconfiguration, fault localisation and resource isolation schemes for CPSs based on many-core networks.
4) Up to 50% reduction in the effort designers put in reliability related tasks by developing an automated and complete sign-off tool.
5) Up to 10% savings in the total area as well as power consumption achieved by optimising hardware protection logic overhead.
These improvements result in the following overall expected impacts to future CPSs:
• 30-40% reduction of development time
• 40% reduction in maintenance costs
This will translate to cheaper, yet dependable CPSs for the society.