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- Saadatmand, Mehrdad, 1980-
(författare)
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Preservation of Extra-Functional Properties in Embedded Systems Development
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The interaction of embedded systems with their environments and their resource limitations make it important to take into account properties such as timing, security, and resource consumption in designing such systems. These so-called Extra-Functional Properties (EFPs) capture and describe the quality and characteristics of a system, and they need to be taken into account from early phases of development and throughout the system's lifecycle. An important challenge in this context is to ensure that the EFPs that are defined at early design phases are actually preserved throughout detailed design phases as well as during the execution of the system on its platform. In this thesis, we provide solutions to help with the preservation of EFPs; targeting both system design phases and system execution on the platform. Starting from requirements, which form the constraints of EFPs, we propose an approach for modeling Non-Functional Requirements (NFRs) and evaluating different design alternatives with respect to the satisfaction of the NFRs. Considering the relationship and trade-off among EFPs, an approach for balancing timing versus security properties is introduced. Our approach enables balancing in two ways: in a static way resulting in a fixed set of components in the design model that are analyzed and thus verified to be balanced with respect to the timing and security properties, and also in a dynamic way during the execution of the system through runtime adaptation. Considering the role of the platform in preservation of EFPs and mitigating possible violations of them, an approach is suggested to enrich the platform with necessary mechanisms to enable monitoring and enforcement of timing properties. In the thesis, we also identify and demonstrate the issues related to accuracy in monitoring EFPs, how accuracy can affect the decisions that are made based on the collected information, and propose a technique to tackle this problem. As another contribution, we also show how runtime monitoring information collected about EFPs can be used to fine-tune design models until a desired set of EFPs are achieved. We have also developed a testing framework which enables automatic generation of test cases in order verify the actual behavior of a system against its desired behavior. On a high level, the contributions of the thesis are thus twofold: proposing methods and techniques to 1) improve maintenance of EFPs within their correct range of values during system design, 2) identify and mitigate possible violations of EFPs at runtime.
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| 2. |
- Saadatmand, Mehrdad
(författare)
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Satisfying Non-Functional Requirements in Model-Driven Development of Real-Time Embedded Systems
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Design of real-time embedded systems is a complex and challenging task. Part of this complexity originates from their limited resources which incurs handling a big range of Non-Functional Requirements (NFRs). Therefore, satisfaction of NFRs plays an important role in the correctness of the design of these systems. Model-driven development has the potential to reduce the design complexity of real-time embedded systems by increasing the abstraction level, enabling analysis at earlier phases of development and code generation. In this thesis, we identify some of the challenges that exist in model-driven development of real-time embedded systems with respect to NFRs, and provide techniques and solutions that aim to help with the satisfaction of NFRs. Our end goal is to ensure that the set of NFRs defined for a system is not violated at runtime. First, we identify and highlight the challenges of modeling NFRs in telecommunication systems and discuss the application of a UML-based approach for modeling them. Since NFRs have dependencies, and the design decisions to satisfy them cannot be considered in isolation, we propose a model-based approach for trade-off analysis of NFRs to help with the comparison of different design models with respect to the satisfaction level of their NFRs. Following the issue of evaluating the interdependencies of NFRs, we also propose solutions for establishing and maintaining balance between different NFRs. In this regard, we categorize our suggested solutions into static and dynamic. The former refers to a static design and set of features which ensures and guarantees the balance of NFRs, while the latter means establishing balance at runtime by reconfiguring the system and runtime adaptation. Finally, we discuss the role of the execution platform in preservation and monitoring of timing properties in real-time embedded systems and propose an approach to enrich the platform with necessary mechanisms for monitoring them.
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