0000000000297514
AUTHOR
Pedro Gil
Analysis of the influence of processor hidden registers on the accuracy of fault injection techniques
Modern processors tend to increase the number of registers, being part of them not accessible by the instruction set. Traditionally, the effect of faults in these hidden registers has not been considered during system validation using fault injection. In this paper, a study of the importance of faults in hidden registers is performed. Firstly, we have analysed the sensitivity of hidden registers to faults in combinational logic. In a second phase, we have analysed the impact of the faults occurred in hidden registers on system behaviour. A broad set of permanent and transient faults have been injected into the models of two typical commercial microcontrollers, using a VHDL-based fault injec…
Fault Emulation for Dependability Evaluation of VLSI Systems
Advances in semiconductor technologies are greatly increasing the likelihood of fault occurrence in deep-submicrometer manufactured VLSI systems. The dependability assessment of VLSI critical systems is a hot topic that requires further research. Field-programmable gate arrays (FPGAs) have been recently pro posed as a means for speeding-up the fault injection process in VLSI systems models (fault emulation) and for reducing the cost of fixing any error due to their applicability in the first steps of the development cycle. However, only a reduced set of fault models, mainly stuck-at and bit-flip, have been considered in fault emulation approaches. This paper describes the procedures to inje…
Improving the multiple errors detection coverage in distributed embedded systems
Currently, a lot of critical applications in automobile and aircraft avionics are built on fault-tolerant real-time distributed embedded systems. Fault injection techniques have been used extensively in the experimental validation of these systems and it is a challenge to adapt them to the demands of new technologies. This paper deals with the effect of physical faults at pin level on the Communication Network Interface in a prototype based on time-triggered architecture. Due to the essential necessity of observing system behavior during injection experiments, a suitable monitor for distributed embedded systems is proposed. The monitor is used to detect failures in the value domain that cou…
On benchmarking the dependability of automotive engine control applications
The pervasive use of ECUs (electronic control units) in automotive systems motivates the interest of the community in methodologies for quantifying their dependability in a reproducible and cost-effective way. Although the core of modern vehicle engines is managed by the control software embedded in engine ECUs, no practical approach has been proposed so far to characterise the impact of faults on the behaviour of this software. This paper proposes a dependability benchmark for engine control applications. The essential features of such type of applications are first captured in a general model, which is then exploited in order to specify a standard procedure to assess dependability measure…
Fault Injection into VHDL Models: Experimental Validation of a Fault-Tolerant Microcomputer System
This work presents a campaign of fault injection to validate the dependability of a fault tolerant microcomputer system. The system is duplex with cold stand-by sparing, parity detection and a watchdog timer. The faults have been injected on a chip-level VHDL model, using an injection tool designed with this purpose. We have carried out a set of injection experiments (with 3000 injections each), injecting transient and permanent faults of types stuck-at, open-line and indetermination on both the signals and variables of the system, running a workload. We have analysed the pathology of the propagated errors, measured their latency, and calculated both detection and recovery coverage. We have…
Changes in visual function and retinal structure in the progression of Alzheimer's disease
Background Alzheimer's Disease (AD) can cause degeneration in the retina and optic nerve either directly, as a result of amyloid beta deposits, or secondarily, as a result of the degradation of the visual cortex. These effects raise the possibility that tracking ophthalmologic changes in the retina can be used to assess neurodegeneration in AD. This study aimed to detect retinal changes and associated functional changes in three groups of patients consisting of AD patients with mild disease, AD patients with moderate disease and healthy controls by using non-invasive psychophysical ophthalmological tests and optical coherence tomography (OCT). Methods We included 39 patients with mild AD, 2…