On cost-effective reuse of components in the design of complex reconfigurable systems

Design strategies that benefit from the reuse of system components can reduce costs while maintaining or increasing dependability—we use the term dependability to tie together reliability and availability. D3H2 (aDaptive Dependable Design for systems with Homogeneous and Heterogeneous redundancies) is a methodology that supports the design of complex systems with a focus on reconfiguration and component reuse. D3H2 systematizes the identification of heterogeneous redundancies and optimizes the design of fault detection and reconfiguration mechanisms, by enabling the analysis of design alternatives with respect to dependability and cost. In this paper, we extend D3H2 for application to repairable systems. The method is extended with analysis capabilities allowing dependability assessment of complex reconfigurable systems. Analysed scenarios include time-dependencies between failure events and the corresponding reconfiguration actions. We demonstrate how D3H2 can support decisions about fault detection and reconfiguration that seek to improve dependability while reducing costs via application to a realistic railway case study

A FPGA-Based Reconfigurable Software Architecture for Highly Dependable Systems

Nowadays, systems-on-chip are commonly equipped with reconfigurable hardware. The use of hybrid architectures based on a mixture of general purpose processors and reconfigurable components has gained importance across the scientific community allowing a significant improvement of computational performance. Along with the demand for performance, the great sensitivity of reconfigurable hardware devices to physical defects lead to the request of highly dependable and fault tolerant systems. This paper proposes an FPGA-based reconfigurable software architecture able to abstract the underlying hardware platform giving an homogeneous view of it. The abstraction mechanism is used to implement fault tolerance mechanisms with a minimum impact on the system performanc

A Fault Injection Environment for Microprocessor-based Board

Evaluating the faulty behaviour of low-cost microprocessor-based boards is an increasingly important issue, due to their usage in many safety critical systems. To address this issue, the paper describes a software-implemented fault injection system based on the trace exception mode available in most microprocessors. The architecture of the complete fault injection environment is proposed, integrating modules for generating a fault list, for performing their injection and for gathering the results, respectively. Data gathered from some sample benchmark applications are presented The main advantages of the approach are low cost, good portability, and high efficienc

Hierarchical fault tolerance in wireless networked control systems

Wireless Networked Control Systems (WNCS) have recently emerged as a replacement for wired control networks. Wireless networked control systems are more suitable for environments that require higher flexibility and robustness. In previous literature a wireless manufacturing line was proposed. The work-cells communication was through IEEE 802.11 technologies and a switched Ethernet backbone. This thesis is aiming to improve the current solution by adding a supervisor to the existing system. The supervisor could be either in passive or active mode. Passive supervisor would intervene when all controllers in the network fail, while active supervisor would act once any controller on the line fail. The system was simulated using OPNET software with 95% confidence analysis. The ability of the system to withstand external interference was assessed through adding a single band jammer to the OPNET simulation. The system was able to hold up to 8KB interfering file sent from a single band jammer affecting the full Wi-Fi spectrum. All results were subjected to a 95% confidence analysis The performability of passive and active supervisor systems was compared. A Markov model of both systems was built. It was shown that by time, the performability of a passive supervisor system is enhanced while that of an active supervisor system degraded. However, the active supervisor showed a better performability in all cases

Increasing communication reliability in manufacturing environments

This paper is concerned with low cost mechanisms that can increase reliability of machine to machine and machine to cloud communications in increasingly complex manufacturing environments that are prone to disconnections and faults. We propose a novel distributed and cooperative sensing framework that supports localized real time predictive analytics of connectivity patterns and detection of a range of faults together with issuing of notifications and responding on demand queries. We show that our Fault and Disconnection Aware Smart Sensing (FDASS) framework achieves significantly lower packet loss rates and communication delays in the face of unreliable nodes and networks when compared to the state of the art and benchmark approaches