12,113 research outputs found

    Nuclear safety policy working group recommendations on nuclear propulsion safety for the space exploration initiative

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    An interagency Nuclear Safety Working Group (NSPWG) was chartered to recommend nuclear safety policy, requirements, and guidelines for the Space Exploration Initiative (SEI) nuclear propulsion program. These recommendations, which are contained in this report, should facilitate the implementation of mission planning and conceptual design studies. The NSPWG has recommended a top-level policy to provide the guiding principles for the development and implementation of the SEI nuclear propulsion safety program. In addition, the NSPWG has reviewed safety issues for nuclear propulsion and recommended top-level safety requirements and guidelines to address these issues. These recommendations should be useful for the development of the program's top-level requirements for safety functions (referred to as Safety Functional Requirements). The safety requirements and guidelines address the following topics: reactor start-up, inadvertent criticality, radiological release and exposure, disposal, entry, safeguards, risk/reliability, operational safety, ground testing, and other considerations

    Verification and validation in software product line engineering

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    Verification and Validation (V&V) is currently performed during application development for many systems, especially safety-critical and mission-critical systems. However, the V&V process has been limited to single system development. This dissertation describes the extension of V&V from an individual application system to a product line of systems that are developed within an architecture-based software engineering environment.;In traditional V&V, the system provides the context under which the software will be evaluated, and V&V activities occur during all phases of the system development lifecycle. The transition to a product line approach to development removes the individual system as the context for evaluation, and introduces activities that are not directly related to a specific system. This dissertation presents an approach to V&V of software product lines that uses the domain model and the domain architecture as the context for evaluation, and enables V&V to be performed throughout the modified lifecycle introduced by domain engineering.;This dissertation presents three advances that assist in the adaptation of V&V from single application systems to a product line of systems. The first is a framework for performing V&V that includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The second is a detailed method to extend the crucial V&V activity of criticality analysis from single system development to a product line of systems. The third advance is an approach to enable formal reasoning, which is needed for high assurance systems, on systems that are based on commercial-off-the-shelf (COTS) products

    Initial flight qualification and operational maintenance of X-29A flight software

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    A discussion is presented of some significant aspects of the initial flight qualification and operational maintenance of the flight control system softward for the X-29A technology demonstrator. Flight qualification and maintenance of complex, embedded flight control system software poses unique problems. The X-29A technology demonstrator aircraft has a digital flight control system which incorporates functions generally considered too complex for analog systems. Organizational responsibilities, software assurance issues, tools, and facilities are discussed

    Security and Safety Assurance for Aerospace Embedded Systems

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    International audienceThe paper starts with the list of basic principles that guided the development of the SEISES security and safety assurance framework. Then we present the SEISES structure and we provide some examples of assurance objectives and related assurance activities. We detail the convergence between safety and security assurance activities that we have identified. Finally, we introduce the three demonstrators and we summarize the main lessons learnt from these experimentations. We conclude the paper by summarizing the results of the SEISES project, by comparing these results with other approaches dealing with joint safety and security assurance and by listing promising directions for further research

    Index for asset value measure obtained from condition monitoring digitalized data interpretation. A railway asset management application

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    Hosted by the Johannes Kepler University, Linz, Austria. May 23-24, 2019The objective of any asset is to provide value to the organization, being the corner stone to get a highest possible economic benefit in a sustainable way. An effective asset value management demands method that allow measuring and comparing the expected value with the real value realized at any time during its life cycle for value informed decision-making. Digitalization is providing new data about events and states related to asset condition and risk, information that can be reinterpreted to generate value measure strategies. This paper presents a proposal of TVO (Total Value of Ownership) model where it is possible to quantify and measure the value, including its monitoring throughout the life cycle of the asset and/or system. Proposed TVO model is focused on Safety, one of the most relevant value factors for Industry and Infrastructure sectors. Asset events and states are intrinsically linked to the defined failure modes. Consequently, it is necessary to structure the system information around the failure modes that have been defined, in order to obtain a value measurement index. A railway use case is presented

    Gateway Modeling and Simulation Plan

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    This plan institutes direction across the Gateway Program and the Element Projects to ensure that Cross Program M&S are produced in a manner that (1) generate the artifacts required for NASA-STD-7009 compliance, (2) ensures interoperability of M&S exchanged and integrated across the program and, (3) drives integrated development efforts to provide cross-domain integrated simulation of the Gateway elements, space environment, and operational scenarios. This direction is flowed down via contractual enforcement to prime contractors and includes both the GMS requirements specified in this plan and the NASASTD- 7009 derived requirements necessary for compliance. Grounding principles for management of Gateway Models and Simulations (M&S) are derived from the Columbia Accident Investigation Board (CAIB) report and the Diaz team report, A Renewed Commitment to Excellence. As an outcome of these reports, and in response to Action 4 of the Diaz team report, the NASA Standard for Models and Simulations, NASA-STD-7009 was developed. The standard establishes M&S requirements for development and use activities to ensure proper capture and communication of M&S pedigree and credibility information to Gateway program decision makers. Through the course of the Gateway program life cycle M&S will be heavily relied upon to conduct analysis, test products, support operations activities, enable informed decision making and ultimately to certify the Gateway with an acceptable level of risk to crew and mission. To reduce risk associated with M&S influenced decisions, this plan applies the NASA-STD-7009 requirements to produce the artifacts that support credibility assessments and ensure the information is communicated to program management

    Comprehensive Security Framework for Global Threats Analysis

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    Cyber criminality activities are changing and becoming more and more professional. With the growth of financial flows through the Internet and the Information System (IS), new kinds of thread arise involving complex scenarios spread within multiple IS components. The IS information modeling and Behavioral Analysis are becoming new solutions to normalize the IS information and counter these new threads. This paper presents a framework which details the principal and necessary steps for monitoring an IS. We present the architecture of the framework, i.e. an ontology of activities carried out within an IS to model security information and User Behavioral analysis. The results of the performed experiments on real data show that the modeling is effective to reduce the amount of events by 91%. The User Behavioral Analysis on uniform modeled data is also effective, detecting more than 80% of legitimate actions of attack scenarios
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