| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Corneo, Lorenzo, et al.
(författare)
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Service Level Agreements for Safe and Configurable Production Environments
- 2018
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Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - : IEEE. - 1946-0759 .- 1946-0740.
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Konferensbidrag (refereegranskat)abstract
- This paper focuses on Service Level Agreements (SLAs) for industrial applications that aim to port some of the control functionalities to the cloud. In such applications, industrial requirements should be reflected in SLAs. In this paper, we present an approach to integrate safety-related aspects of an industrial application to SLAs. We also present the approach in a use case. This is an initial attempt to enrich SLAs for industrial settings to consider safety aspects, which has not been investigated thoroughly before.
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| 4. |
- Gallina, Barbara, et al.
(författare)
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Towards a Safety-oriented Process Line for Enabling Reuse in Safety Critical Systems Development and Certification
- 2012
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Ingår i: Proceedings of the 2012 IEEE 35th Software Engineering Workshop, SEW 2012. - 9780769549477 ; , s. 148-157
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Konferensbidrag (refereegranskat)abstract
- Safety standards define development processes by indicating the set of partially ordered tasks that have to be executed to achieve acceptably safe systems. Process compliance constitutes a fundamental ingredient in safety argumentation for certification purposes. Certification is a very expensive, time-consuming and quality demanding activity. To increase quality and reduce time and cost, reusebased approaches are being investigated. In this paper, we adopt process line approach in the framework of safety processes. This means that we treat a family of processes as a product line, and we identify commonalities and variabilities between them. The resulting information guides developers in reusing parts of the process, the system and safety case, e.g. which parts to make more generic, isolating changes in others to avoid ripple effects etc..
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| 5. |
- Girs, Svetlana, et al.
(författare)
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Contract-Based Assurance for Wireless Cooperative Functions of Vehicular Systems
- 2017
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Ingår i: IECON 2017 - 43RD ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY. - 9781538611272 ; , s. 8391-8396
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Konferensbidrag (refereegranskat)abstract
- Cooperation of vehicular systems is the stepping stone towards both road and indoor smart transportation systems. It aims at increasing transportation efficiency and safety compared to the stand-alone vehicular systems. The usage of wireless communication as the foundation of such safety-critical cooperation needs to be embraced with all its benefits and flaws compared to the wired communication. The cooperative functions need to be designed to adapt to the varying reliability of the wireless communication channels such that both the stand-alone vehicles as well as the smart transportation system formed by their cooperation are deemed sufficiently safe. In this paper we build upon a contract-based runtime monitoring architecture and propose a methodology for assuring adaptive behaviour of transportation with respect to the wireless communication channel failures. More specifically, we elaborate how safety analysis of the interaction of the wirelessly connected vehicles can be used as the basis for derivation of the adaptive modes and the corresponding contracts. Furthermore, we discuss how such contracts can be used as the basis for assurance of the adaptive wireless cooperation. We illustrate the proposed methodology on a smart transportation system of a factory.
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| 6. |
- Jaradat, Omar, et al.
(författare)
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An Approach to Maintaining Safety Case Evidence After A System Change
- 2014
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Ingår i: 2014 Tenth European Dependable Computing Conference EDCC 2014.
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Konferensbidrag (refereegranskat)abstract
- Developers of some safety critical systems construct a safety case. Developers changing a system during development or after release must analyse the change's impact on the safety case. Evidence might be invalidated by changes to the system design, operation, or environmental context. Assumptions valid in one context might be invalid elsewhere. The impact of change might not be obvious. This paper proposes a method to facilitate safety case maintenance by highlighting the impact of changes.
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| 7. |
- Jaradat, Omar, 1981-, et al.
(författare)
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Challenges of Safety Assurance for Industry 4.0
- 2017
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Ingår i: European Dependable Computing Conference EDCC'17. - Geneva, Switzerland : IEEE Computer Society. - 9781538606025 ; , s. 103-106
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Konferensbidrag (refereegranskat)abstract
- The Internet-of-Things (IoT) has enabled Industry 4.0 as a new manufacturing paradigm. The envisioned future of Industry 4.0 and Smart Factories is to be highly configurable and composed mainly of the 'things' that are expected to come with some, often partial, assurance guarantees. However, many factories are categorised as safety-critical, e.g. due to the use of heavy machinery or hazardous substances. As such, some of the guarantees provided by the 'things', e.g. related to performance and availability, are deemed as necessary in order to ensure the safety of the manufacturing processes and the resulting products. In this paper, we explore key safety challenges posed by Industry 4.0 and identify the characteristics that its safety assurance should exhibit. We propose a set of safety assurance responsibilities, e.g. system integrators, cloud service providers and `things' suppliers. Finally, we reflect on the desirable modularity of such a safety assurance approach as a basis for cooperative, on-demand and continuous reasoning for Industry 4.0 architectures and services.
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| 8. |
- Jaradat, Omar, 1981-
(författare)
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Contracts-Based Maintenance of Safety Cases
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Safety critical systems are those systems whose failure could result in loss of life, significant property damage, or damage to the environment. System safety is a major property that shall be adequately assured to avoid any severe outcomes in safety critical systems. Safety assurance should provide justified confidence that all potential risks due to system failures are either eliminated or acceptably mitigated. System developers in many domains (e.g., automotive, avionics, railways) should provide convincing arguments regarding the safe performance of their systems to a national or international regulatory authority and obtain approvals before putting the system into service. Building 'Safety cases' is a proven technique to argue about and communicate systems' safety and it has become a common practice in many safety critical system domains. System developers use safety cases to articulate claims about how systems meet their safety requirements and objectives, collect and document items of evidence, and construct a safety argument to show how the available items of evidence support the claims.Safety critical systems are evolutionary and constantly subject to preventive, perfective, corrective or adaptive changes during both the development and operational phases. Changes to any part of those systems can undermine the confidence in safety since changes can refute articulated claims about safety or challenge the supporting evidence on which this confidence relies. Hence, safety cases need to be built as living documents that should always be maintained to justify the safety status of the associated system and evolve as these systems evolve. However, building safety cases are costly since they require a significant amount of time and efforts to define the safety objectives, generate the required evidence and conclude the underlying logic behind the safety case arguments. Safety cases document highly dependent elements such as safety goals, assumptions and evidence. Seemingly minor changes may have a major impact. Changes to a system or its environment can necessitate a costly and painstaking impact analysis for systems and their safety cases. In addition, changes may require system developers to generate completely new items of evidence by repeating the verification activities. Therefore, changes can exacerbate the cost of producing and maintaining safety cases. Safety contracts have been proposed as a means for helping to manage changes. There have been works that discuss the usefulness of contracts for reusability and maintainability. However, there has been little attention on how to derive them and how exactly they can be utilised for system or safety case maintenance.The main goal of this thesis is to support the change impact analysis as a key factor to enhance the maintainability of safety cases. We focus on utilising safety contracts to achieve this goal. To address this, we study how safety contracts can support essential factors for any useful change management process, such as (1) identifying the impacted elements and those that are not impacted, (2) minimising the number of impacted safety case elements, and (3) reducing the work needed to make the impacted safety case elements valid again. The preliminary finding of our study reveals that using safety contracts can be promising to develop techniques and processes to facilitate safety case maintenance. The absence of safety case maintenance guidelines from safety standards and the lack of systematic and methodical maintenance techniques have motivated the work of this thesis. Our work is presented through a set of developed and assessed techniques, where these techniques utilise safety contracts to achieve the overall goal by various contributions. We begin by a framework for evaluation of the impact of change on safety critical systems and safety cases. Through this, we identify and highlight the most sensitive system components to a particular change. We propose new ways to associate system design elements with safety case arguments to enable traceability. How to identify and reduce the propagation of change impact is addressed subsequently. Our research also uses safety contracts to enable through-life safety assurance by monitoring and detecting any potential mismatch between the design safety assumptions and the actual behaviour of the system during its operational phase. More specifically, we use safety contracts to capture thresholds of selected safety requirements and compare them with the runtime related data (i.e., operational data) to continuously assess and evolve the safety arguments.In summary, our proposed techniques pave the way for cost-effective maintenance of safety cases upon preventive, perfective, corrective or adaptive changes in safety critical systems thus helping better decision support for change impact analysis.
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| 9. |
- Jaradat, Omar, 1981-, et al.
(författare)
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Deriving Hierarchical Safety Contracts
- 2015
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Ingår i: Proceedings. - 9781467393768 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Safety cases need significant amount of time and effort to produce. The required amount of time and effort can be dramatically increased due to system changes as safety cases should be maintained before they can be submitted for certification or re-certification. Anticipating potential changes is useful since it reveals traceable consequences that will eventually reduce the maintenance efforts. However, considering a complete list of anticipated changes is difficult. What can be easier though is to determine the flexibility of system components to changes. Using sensitivity analysis is useful to measure the flexibility of the different system properties to changes. Furthermore, contracts have been proposed as a means for facilitating the change management process due to their ability to record the dependencies among system’s components. In this paper, we extend a technique that uses a sensitivity analysis to derive safety contracts from Fault Tree Analyses (FTA) and uses these contracts to trace changes in the safety argument. The extension aims to enabling the derivation of hierarchical and correlated safety contracts.We motivate the extension through an illustrative example within which we identify limitations of the technique and discuss potential solutions to these limitations.
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| 10. |
- Jaradat, Omar, 1981-
(författare)
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Enhancing the Maintainability of Safety Cases Using Safety Contracts
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Safety critical systems are those systems whose failure could result in loss of life, significant property damage, or damage to the environment. These systems require high quality and dependability levels in them, where system safety is a major property that should be adequately assured to avoid any severe outcomes. Many safety critical systems in different domains (e.g., avionics, railway, automotive, etc.) are subject to a certification. The certification process is based on an evaluation of whether the associated hazards to a system are mitigated to an acceptable level. Safety cases are often required to demonstrate how a regulatory body can reasonably conclude that a system is acceptably safe from the evidence available. The development of safety cases has become common practice in many safety critical system domains. However, safety cases are costly since they need significant amount of time and efforts to produce. This cost can be dramatically increased (even for already certified systems) due to system changes as they require maintaining the safety case before it can be submitted for certification. Anticipating potential changes is useful since it reveals traceable consequences that will eventually reduce the maintenance efforts. However, considering a complete list of anticipated changes is difficult. What can be easier though is to determine the flexibility of system components to changes.Sensitivity analysis has been proposed as a useful tool to measure the flexibility of the different system properties to changes. Furthermore, the concept of contracts have been proposed as a means for facilitating the change management process due to their ability to record the dependencies among system's components. In this thesis, we use sensitivity analysis to support changes prediction and prioritisation. We also use safety contracts to record the information of changes that will ultimately advise the engineers what to consider and check when changes actually happen.
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