7,545 research outputs found
Collecting and Analyzing Failure Data of Bluetooth Personal Area Networks
This work presents a failure data analysis campaign on
Bluetooth Personal Area Networks (PANs) conducted on
two kind of heterogeneous testbeds (working for more than
one year). The obtained results reveal how failures distribution
are characterized and suggest how to improve the
dependability of Bluetooth PANs. Specically, we dene the
failure model and we then identify the most effective recovery
actions and masking strategies that can be adopted for
each failure. We then integrate the discovered recovery actions
and masking strategies in our testbeds, improving the
availability and the reliability of 3.64% (up to 36.6%) and
202% (referred to the Mean Time To Failure), respectively
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 synthesis of logic and bio-inspired techniques in the design of dependable systems
Much of the development of model-based design and dependability analysis in the design of dependable systems, including software intensive systems, can be attributed to the application of advances in formal logic and its application to fault forecasting and verification of systems. In parallel, work on bio-inspired technologies has shown potential for the evolutionary design of engineering systems via automated exploration of potentially large design spaces. We have not yet seen the emergence of a design paradigm that effectively combines these two techniques, schematically founded on the two pillars of formal logic and biology, from the early stages of, and throughout, the design lifecycle. Such a design paradigm would apply these techniques synergistically and systematically to enable optimal refinement of new designs which can be driven effectively by dependability requirements. The paper sketches such a model-centric paradigm for the design of dependable systems, presented in the scope of the HiP-HOPS tool and technique, that brings these technologies together to realise their combined potential benefits. The paper begins by identifying current challenges in model-based safety assessment and then overviews the use of meta-heuristics at various stages of the design lifecycle covering topics that span from allocation of dependability requirements, through dependability analysis, to multi-objective optimisation of system architectures and maintenance schedules
Development of a Security Methodology for Cooperative Information Systems: The CooPSIS Project
Since networks and computing systems are vital components of today\u27s life, it is of utmost importance to endow them with the capability to survive physical and logical faults, as well as malicious or deliberate attacks. When the information system is obtained by federating pre-existing local systems, a methodology is needed to integrate security policies and mechanisms under a uniform structure. Therefore, in building distributed information systems, a methodology for analysis, design and implementation of security requirements of data and processes is essential for obtaining mutual trust between cooperating organizations. Moreover, when the information system is built as a cooperative set of e-services, security is related to the type of data, to the sensitivity context of the cooperative processes and to the security characteristics of the communication paradigms. The CoopSIS (Cooperative Secure Information Systems) project aims to develop methods and tools for the analysis, design, implementation and evaluation of secure and survivable distributed information systems of cooperative type, in particular with experimentation in the Public Administration Domain. This paper presents the basic issues of a methodology being conceived to build a trusted cooperative environment, where data sensitivity parameters and security requirements of processes are taken into account. The milestones phases of the security development methodology in the context of this project are illustrated
Supporting group maintenance through prognostics-enhanced dynamic dependability prediction
Condition-based maintenance strategies adapt maintenance planning through the integration of online condition monitoring of assets. The accuracy and cost-effectiveness of these strategies can be improved by integrating prognostics predictions and grouping maintenance actions respectively. In complex industrial systems, however, effective condition-based maintenance is intricate. Such systems are comprised of repairable assets which can fail in different ways, with various effects, and typically governed by dynamics which include time-dependent and conditional events. In this context, system reliability prediction is complex and effective maintenance planning is virtually impossible prior to system deployment and hard even in the case of condition-based maintenance. Addressing these issues, this paper presents an online system maintenance method that takes into account the system dynamics. The method employs an online predictive diagnosis algorithm to distinguish between critical and non-critical assets. A prognostics-updated method for predicting the system health is then employed to yield well-informed, more accurate, condition-based suggestions for the maintenance of critical assets and for the group-based reactive repair of non-critical assets. The cost-effectiveness of the approach is discussed in a case study from the power industry
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