A Model-Based Soft Errors Risks Minimization Approach

Minimizing the risk of system failure in any computer structure requires identifying those components whose failure is likely to impact on system functionality. Clearly, the degree of protection or prevention required against faults is not the same for all components. Tolerating soft errors can be much improved if critical components can be identified at an early design phase and measures are taken to lower their criticalities at that stage. This improvement is achieved by presenting a criticality ranking (among the components) formed by combining a prediction of faults, consequences of them, and a propagation of errors at the system modeling phase; and pointing out ways to apply changes in the model to minimize the risk of degradation of desired functionalities. Case study results are given to validate the approach

A Novel Approach to Minimizing the Risks of Soft Errors in Mobile and Ubiquitous Systems

A novel approach to minimizing the risks of soft errors at modelling level of mobile and ubiquitous systems is outlined. From a pure dependability viewpoint, critical components, whose failure is likely to impact on system functionality, attract more attention of protection/prevention mechanisms (against soft errors) than others do. Tolerating soft errors can be much improved if critical components can be identified at an early design phase and measures are taken to lower their criticalities at that stage. This improvement is achieved by presenting a criticality ranking (among the components) formed by combining a prediction of soft errors, consequences of them, and a propagation of failures at system modelling phase; and pointing out the ways to apply changes in the model to minimize the risks of degradation of desired functionalities. Case study results are given to illustrate and validate the approach

Building safe software

Murphy is a set of techniques and tools under investigation for their potential in enhancing the safety of software. This paper describes some of the work which has been done and some which is planned

Identifying dependability requirements for space software systems

Computer systems are increasingly used in space, whether in launch vehicles, satellites, ground support and payload systems. Software applications used in these systems have become more complex, mainly due to the high number of features to be met, thus contributing to a greater probability of hazards related to software faults. Therefore, it is fundamental that the specification activity of requirements have a decisive role in the effort of obtaining systems with high quality and safety standards. In critical systems like the embedded software of the Brazilian Satellite Launcher, ambiguity, non-completeness, and lack of good requirements can cause serious accidents with economic, material and human losses. One way to assure quality with safety, reliability and other dependability attributes may be the use of safety analysis techniques during the initial phases of the project in order to identify the most adequate dependability requirements to minimize possible fault or failure occurrences during the subsequent phases. This paper presents a structured software dependability requirements analysis process that uses system software requirement specifications and traditional safety analysis techniques. The main goal of the process is to help to identify a set of essential software dependability requirements which can be added to the software requirement previously specified for the system. The final results are more complete, consistent, and reliable specifications

Sensor failure detection system

Advanced concepts for detecting, isolating, and accommodating sensor failures were studied to determine their applicability to the gas turbine control problem. Five concepts were formulated based upon such techniques as Kalman filters and a screening process led to the selection of one advanced concept for further evaluation. The selected advanced concept uses a Kalman filter to generate residuals, a weighted sum square residuals technique to detect soft failures, likelihood ratio testing of a bank of Kalman filters for isolation, and reconfiguring of the normal mode Kalman filter by eliminating the failed input to accommodate the failure. The advanced concept was compared to a baseline parameter synthesis technique. The advanced concept was shown to be a viable concept for detecting, isolating, and accommodating sensor failures for the gas turbine applications

Network-on-Chip -based Multi-Processor System-on-Chip: Towards Mixed-Criticality System Certification

L'abstract è presente nell'allegato / the abstract is in the attachmen

LLV - Lunar Logistics Vehicle Final report

Design of unmanned space vehicle for landing 2500 pound payload on moo

Towards a scope management of non-functional requirements in requirements engineering

Getting business stakeholders’ goals formulated clearly and project scope defined realistically increases the chance of success for any application development process. As a consequence, stakeholders at early project stages acquire as much as possible knowledge about the requirements, their risk estimates and their prioritization. Current industrial practice suggests that in most software projects this scope assessment is performed on the user’s functional requirements (FRs), while the non-functional requirements (NFRs) remain, by and large, ignored. However, the increasing software complexity and competition in the software industry has highlighted the need to consider NFRs as an integral part of software modeling and development. This paper contributes towards harmonizing the need to build the functional behavior of a system with the need to model the associated NFRs while maintaining a scope management for NFRs. The paper presents a systematic and precisely defined model towards an early integration of NFRs within the requirements engineering (RE). Early experiences with the model indicate its ability to facilitate the process of acquiring the knowledge on the priority and risk of NFRs

Process of designing robust, dependable, safe and secure software for medical devices: Point of care testing device as a case study

This article has been made available through the Brunel Open Access Publishing Fund.Copyright © 2013 Sivanesan Tulasidas et al. This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).Brunel Open Access Publishing Fund

Programmable Logic Device (PLD) Safety Design Approach

Programmable Logic Devices (PLDs) in ordnance fuze and ignition systems have well-defined design and verification requirements based on U.S. Department of Defense (DoD) Safety Review Board guidelines and military standards. However, there are few established safety design and verification requirements for PLDs used in non-fuze safety-significant applications. The primary objective of this paper is to (1) establish a process that assures that PLDs in products and systems are developed and tested to a level of rigor commensurate with the safety risk of the specified application, including fuze and non-fuze safety systems, and (2) to comply with recent guidance from DoD Software System Safety Technical Review Panels on firmware and programmable logic safety assurance. The paper’s secondary objective is to make the PLD safety process applicable to non-DoD and commercial programs such as autonomous vehicles, aerospace and energy systems. To meet this objective, this document incorporates best practices of NASA, commercial aviation, the Nuclear Regulatory Commission (NRC), and from international programmable electronic functional safety standards