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

High availability using virtualization - 3RC

High availability has always been one of the main problems for a data center. Till now high availability was achieved by host per host redundancy, a highly expensive method in terms of hardware and human costs. A new approach to the problem can be offered by virtualization. Using virtualization, it is possible to achieve a redundancy system for all the services running on a data center. This new approach to high availability allows the running virtual machines to be distributed over a small number of servers, by exploiting the features of the virtualization layer: start, stop and move virtual machines between physical hosts. The 3RC system is based on a finite state machine, providing the possibility to restart each virtual machine over any physical host, or reinstall it from scratch. A complete infrastructure has been developed to install operating system and middleware in a few minutes. To virtualize the main servers of a data center, a new procedure has been developed to migrate physical to virtual hosts. The whole Grid data center SNS-PISA is running at the moment in virtual environment under the high availability system.Comment: 10 page

Integrated Power Systems in All Electric Ships: Dependability Oriented Design

This work aims at providing a comprehensive and, as far as possible, standard and widely supported approach to a dependable design of all electric ship integrated power systems. The proposed approach is based upon latest development of dependability theory made recently available, from its founding lexicon and taxonomy to investigation tools and relevant international rules. In its first part, this work analyses present rule requirements governing the discipline of designing an integrated power system serving an all electric ship. Analysis covers system definitions (what is what) in terms of taxonomy and associated concepts; system required performances both in terms of delivered services and in terms of reaction to anticipated reactions to predetermined fault scenarios. In its second part, this work briefly presents latest developments in the theory and in the tools theory brings along: lexicon, taxonomy, system analysis, benchmarking and enforcing techniques. During this development, emphasis is posed on the fact that design documentation, be it owners’ technical specification, classification society rule book or international standard, often recall dependability concepts, without fully exploiting the potential theory is promising, or the completeness of its definition corpus. In its third part, this work applies dependability concepts to a real case scenario, an integrated power system installed on a recent cruise ship vessel. This application, albeit suffering from an important lack of information, due to copyrighting and industrial intellectual property rights, produces an informative example on the enquiring method and relevant deliverable: a system model, obtained in a strongly standardized way that permits a comprehensive and accurate dependability study, to be realized using tools and techniques defined in international standard. Results of this analysis are, as a consequence of method strong structure, repeatable and consistent, and allow quick verification of requirements. Analysis results, even though partial and superficial owing to already mentioned lack of accurate information, are offering some original view points. They are commented and classified according to indexes defined earlier. In its fourth part, this works presents proposals to be applied to systems which exhibited low values of indexes. Such proposals are briefly analyzed in terms of index value variations; in doing this a quantification of improvement that could be obtained is given. Finally, in its fifth part, this work shortly presents future research directions to improve investigation method. This work reports elements of project management and maritime law as well, this in force of the multidisciplinary nature of dependability theory, and its repercussion on different sector of the marine industry, besides engineering. It is show how present method can fit the actual engineering process, and can provide a common language serving as substrate for various disciplines, like the ones mentioned