Computer Science

Permanent URI for this collectionhttps://hdl.handle.net/10679/43

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Now showing 1 - 6 of 6

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Composing domain-specific physical models with general-purpose software modules in embedded control software
(Springer Science+Business Media, 2014-02) Roo, A. de; Sözer, Hasan; Akşit, M.; Computer Science; SÖZER, Hasan
A considerable portion of software systems today are adopted in the embedded control domain. Embedded control software deals with controlling a physical system, and as such models of physical characteristics become part of the embedded control software. In current practices, usually general-purpose languages (GPL), such as C/C++ are used for embedded systems development. Although a GPL is suitable for expressing general-purpose computation, it falls short in expressing the models of physical characteristics as desired. This reduces not only the readability of the code but also hampers reuse due to the lack of dedicated abstractions and composition operators. Moreover, domain-specific static and dynamic checks may not be applied effectively. There exist domain-specific modeling languages (DSML) and tools to specify models of physical characteristics. Although they are commonly used for simulation and documentation of physical systems, they are often not used to implement embedded control software. This is due to the fact that these DSMLs are not suitable to express the general-purpose computation and they cannot be easily composed with other software modules that are implemented in GPL. This paper presents a novel approach to combine a DSML to model physical characteristics and a GPL to implement general-purpose computation. The composition filters model is used to compose models specified in the DSML with modules specified in the GPL at the abstraction level of both languages. As such, this approach combines the benefits of using a DSML to model physical characteristics with the freedom of a GPL to implement general-purpose computation. The approach is illustrated using two industrial case studies from the printing systems domain.
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Feature-based rationale management system for supporting software architecture adaptation
(World Scientific Publishing Co., 2012-11) Tekinerdoğan, B.; Sözer, Hasan; Akşit, M.; Computer Science; SÖZER, Hasan
Each software architecture design is the result of a broad set of design decisions and their justifications, that is, the design rationale. Capturing the design rationale is important for a variety of reasons such as enhancing communication, reuse and maintenance. Unfortunately, it appears that there is still a lack of appropriate methods and tools for effectively capturing and managing the architecture design rationale. In this paper we present a feature-based rationale management approach and the corresponding tool environment ArchiRationale for supporting software architecture adaptation. The approach takes as input an existing architecture and captures the design rationale for adapting the architecture for a given quality concern. For this we define a feature model that includes the possible set of architectural tactics to realize the quality concern. The presented approach captures the rationale for deciding on feature selections and for selecting the corresponding architecture design alternatives. ArchiRationale customizes and integrates the Eclipse plugin tools XFeature, ArchStudio and XQuery to provide tool support for capturing, storing and accessing the design rationale. We illustrate the approach for adapting a software architecture for fault tolerance.
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MOO: An architectural framework for runtime optimization of multiple system objectives in embedded control software
(Elsevier, 2013-10) Roo, A. de; Sözer, Hasan; Bergmans, L.; Akşit, M.; Computer Science; SÖZER, Hasan
Today's complex embedded systems function in varying operational conditions. The control software adapts several control variables to keep the operational state optimal with respect to multiple objectives. There exist well-known techniques for solving such optimization problems. However, current practice shows that the applied techniques, control variables, constraints and related design decisions are not documented as a part of the architecture description. Their implementation is implicit, tailored for specific characteristics of the embedded system, tightly integrated into and coupled with the control software, which hinders its reusability, analyzability and maintainability. This paper presents an architectural framework to design, document and realize multi-objective optimization in embedded control software. The framework comprises an architectural style together with its visual editor and domain-specific analysis tools, and a code generator. The code generator generates an optimizer module specific for the given architecture and it employs aspect-oriented software development techniques to seamlessly integrate this module into the control software. The effectiveness of the framework is validated in the context of an industrial case study from the printing systems domain.
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Optimizing decomposition of software architecture for local recovery
(Springer Science+Business Media, 2013-06) Sözer, Hasan; Tekinerdoğan, B.; Akşit, M.; Computer Science; SÖZER, Hasan
The increasing size and complexity of software systems has led to an amplified number of potential failures and as such makes it harder to ensure software reliability. Since it is usually hard to prevent all the failures, fault tolerance techniques have become more important. An essential element of fault tolerance is the recovery from failures. Local recovery is an effective approach whereby only the erroneous parts of the system are recovered while the other parts remain available. For achieving local recovery, the architecture needs to be decomposed into separate units that can be recovered in isolation. Usually, there are many different alternative ways to decompose the system into recoverable units. It appears that each of these decomposition alternatives performs differently with respect to availability and performance metrics. We propose a systematic approach dedicated to optimizing the decomposition of software architecture for local recovery. The approach provides systematic guidelines to depict the design space of the possible decomposition alternatives, to reduce the design space with respect to domain and stakeholder constraints and to balance the feasible alternatives with respect to availability and performance. The approach is supported by an integrated set of tools and illustrated for the open-source MPlayer software.
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Runtime verification of component-based embedded software
(Springer, 2011) Sözer, Hasan; Hofmann, C; Tekinerdoğan, B.; Akşit, M.; Computer Science; SÖZER, Hasan
To deal with increasing size and complexity, component-based software development has been employed in embedded systems. Due to several faults, components can make wrong assumptions about the working mode of the system and the working modes of the other components. To detect mode inconsistencies at runtime, we propose a “lightweight” error detection mechanism, which can be integrated with component-based embedded systems. We define links among three levels of abstractions: the runtime behavior of components, the working mode specifications of components and the specification of the working modes of the system. This allows us to detect the user observable runtime errors. The effectiveness of the approach is demonstrated by implementing a software monitor integrated into a TV system.
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Verification and analysis of domain-specific models of physical characteristics in embedded control software
(Elsevier, 2012-12) Roo, A. de; Sözer, Hasan; Akşit, M.; Computer Science; SÖZER, Hasan
ContextA considerable portion of the software systems today are adopted in the embedded control domain. Embedded control software deals with controlling a physical system, and as such models of physical characteristics become part of the embedded control software.ObjectiveDue to the evolution of system properties and increasing complexity, faults can be left undetected in these models of physical characteristics. Therefore, their accuracy must be verified at runtime. Traditional runtime verification techniques that are based on states/events in software execution are inadequate in this case. The behavior suggested by models of physical characteristics cannot be mapped to behavioral properties of software. Moreover, implementation in a general-purpose programming language makes these models hard to locate and verify. Therefore, this paper proposes a novel approach to perform runtime verification of models of physical characteristics in embedded control software.MethodThe development of an approach for runtime verification of models of physical characteristics and the application of the approach to two industrial case studies from the printing systems domain.ResultsThis paper presents a novel approach to specify models of physical characteristics using a domain-specific language, to define monitors that detect inconsistencies by exploiting redundancy in these models, and to realize these monitors using an aspect-oriented approach. We complement runtime verification with static analysis to verify the composition of domain-specific models with the control software written in a general-purpose language.ConclusionsThe presented approach enables runtime verification of implemented models of physical characteristics to detect inconsistencies in these models, as well as broken hardware components and wear and tear of hardware in the physical system. The application of declarative aspect-oriented techniques to realize runtime verification monitors increases modularity and provides the ability to statically verify this realization. The complementary static and runtime verification techniques increase the reliability of embedded control software.

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Browsing by Author "Akşit, M."