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Towards Stronger Property Preservation in RealTime Systems Synthesis ∗
, 2006
"... A key aspect in concurrent realtime system development is to build a model from which a “correct ” implementation can be synthesised. Hence, it is important to understand the relation between the properties of a model and of its corresponding implementation. In this paper, we use timed action seque ..."
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A key aspect in concurrent realtime system development is to build a model from which a “correct ” implementation can be synthesised. Hence, it is important to understand the relation between the properties of a model and of its corresponding implementation. In this paper, we use timed action sequences to describe the behaviour of a realtime system. We first define a notion of distance as a metric to express the observable property preservation between timed action sequences. Furthermore, considering both model and implementation as sets of timed action sequences, we show that a smaller distance between them, and hence a stronger observable property preservation, is obtained when urgency on the execution of observable actions is imposed over the execution of unobservable ones. Based on this result, we extend a previous model synthesis approach to generate from a model an implementation with stronger property preservation. By means of a case study, we show how the proposed approach can be applied to the development of realtime systems. 1.
Predictability in realtime system development (1) semantics support from development languages
 In Proceedings the Forum on Specification and Design Language, FDL’04
, 2004
"... With the increasing complexity of realtime control systems, it is important to have sufficient predictability support for a development approach in order to promote the likelihood of the development success. To achieve this, the abstraction/refinement activities during the development should be pe ..."
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With the increasing complexity of realtime control systems, it is important to have sufficient predictability support for a development approach in order to promote the likelihood of the development success. To achieve this, the abstraction/refinement activities during the development should be performed in an efficient way. In this paper, we first briefly introduce the role of the semantics of languages in system development. Then we investigated how the semantics of development languages can support efficient abstraction/refinement. Subsequently, the insufficient predictability support of existing design approaches for realtime control systems are illustrated by an example. Finally, a predictable development approach for realtime control systems is introduced to overcome this problem. 1
PropertyPreservation Synthesis for Unified Controland DataOriented Models ∗
"... In the Software/Hardware Engineering modeldriven design methodology, the preservation of realtime system properties can be guaranteed up to a small timedeviation in the model synthesis. Therefore, this methodology is well suited for the design of controlsystems in which execution times of action ..."
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In the Software/Hardware Engineering modeldriven design methodology, the preservation of realtime system properties can be guaranteed up to a small timedeviation in the model synthesis. Therefore, this methodology is well suited for the design of controlsystems in which execution times of actions are small; thus the timedeviations obtained are small. However, in systems containing timeintensive computations, the timedeviations become large and, consequently, the realtime properties are much weakened. This paper gives an initial idea for obtaining stronger propertypreservation by abstracting from the internal actions of a system and counting only the observable actions for the timedeviation. In this way, a unified way of analysis and synthesis of a larger area of realtime applications can be obtained, which would allow designers to reason about different properties of systems. 1
Predicting implementation accuracy for realtime control systems
, 2005
"... Modeldriven approaches proved themselves not suited yet to support realtime software development. Even if they have the ability of capturing adequately both functional and nonfunctional (timing) characteristics of a system, they still lack an appropriate mechanism of generating an implementation ..."
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Modeldriven approaches proved themselves not suited yet to support realtime software development. Even if they have the ability of capturing adequately both functional and nonfunctional (timing) characteristics of a system, they still lack an appropriate mechanism of generating an implementation from a model while preserving the properties verified. In previous work we have proven that, if the implementation trace is very close (ǫclose) to a model trace, the properties verified in the model are preserved up to ǫ in the system realisation. This deviation is due to the model assumption of zerotime for computational actions that, in reality, no target platform can ensure. This paper proposes an approach for estimating the timedeviation between model and implementation, by modelling the realisation of the system when software components would run on the target platform. The approach is based on Software/Hardware Engineering method for complex realtime systems design and the Ychart scheme concepts. 1
Towards CorrectnessPreserving Synthesis for RealTime Software
"... It is wellknown that realtime systems (especially realtime software) impose a lot of challenges to system design and implementation. In this paper, we first analyze the difficulties the design problems stem from. Then we investigate the merits and pitfalls of major design styles by evaluating them ..."
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It is wellknown that realtime systems (especially realtime software) impose a lot of challenges to system design and implementation. In this paper, we first analyze the difficulties the design problems stem from. Then we investigate the merits and pitfalls of major design styles by evaluating them against predictability, compositionality, efficiency, expressive power and debuggability. Finally we propose a design approach which combines both the timedriven and eventdriven design styles for realtime software development. The proposed approach consists two consequent procedures: 1. Platformindependent design provides a virtual execution environment in which the design description is uniquely interpreted and formally evaluated by verification and simulation techniques without being affected by nondeterministic factors of the underlying platform. Base on the analysis results, the model can be elaborated smoothly to satisfy all essential functional and critical timing requirements.
Similarities between Timing Constraint Sets: Towards Interchangeable Constraint Models for RealWorld Software Systems
"... Abstract—Traditionally, given two timing constraint sets, their relationship is defined by their timed trace inclusions. This approach only gives a boolean answer to if one set of constraints is contained within the other. In this paper, we first introduce a quantitative measure to describe the clos ..."
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Abstract—Traditionally, given two timing constraint sets, their relationship is defined by their timed trace inclusions. This approach only gives a boolean answer to if one set of constraints is contained within the other. In this paper, we first introduce a quantitative measure to describe the closeness or the similarity between two timing constraint sets. We intend to study the satisfaction bounds of similar timing constraint sets by similar timed systems. Such bounds will help improve the predictability of realtime systems in realworld applications and provide guidance for selftuning systems. I.
Chapter 1 PLATFORMINDEPENDENT DESIGN FOR EMBEDDED REALTIME SYSTEMS ∗
"... Abstract With the increasing complexity of the emerging embedded realtime systems, traditional design approaches can not provide sufficient support for the development of these systems anymore. They especially lack the ability to trace and analyse realtime system properties. In this paper, we inve ..."
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Abstract With the increasing complexity of the emerging embedded realtime systems, traditional design approaches can not provide sufficient support for the development of these systems anymore. They especially lack the ability to trace and analyse realtime system properties. In this paper, we investigate the design difficulties for embedded realtime systems and propose several principles for coping with these difficulties, which should be incorporated by an “adequate ” design approach. Several prevailing design approaches are evaluated against these principles and their merits and drawbacks are examined and illustrated by examples. Finally, a platformindependent approach (POOSL[van der Putten and Voeten, 1997], [Geilen, 2002] + rotalumis[van Bokhoven, 2002]) is introduced to remedy these design problems for embedded realtime systems. Initial
Chapter 1 PREDICTABILITY IN REALTIME SYSTEM DEVELOPMENT
"... Abstract The large gap existing between requirements and realizations has been a pertinacious problem in complex system design. This holds in particular for realtime systems with strict timing constraints and criticalsafety requirements. Designers have to rely on a multistep design process, where ..."
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Abstract The large gap existing between requirements and realizations has been a pertinacious problem in complex system design. This holds in particular for realtime systems with strict timing constraints and criticalsafety requirements. Designers have to rely on a multistep design process, where design decisions are made at different modelling levels. To ensure the effectiveness of this design process, predictability should be wellsupported by design approaches, allowing designers to predict properties of future design outcomes based on existing design results. In this chapter, we first discuss the role of the semantics of design languages and investigated how they can support a predictable design process. Then, the deficiencies, w.r.t. predictability support, of existing design approaches for realtime systems are illustrated by an example. Finally, a predictable design approach for realtime systems is introduced to overcome this problem. Keywords: Realtime, predictability, semantics, compositionality, composability
Robust Sampling for MITL
"... Robust Sampling for MITL Specifications Realtime temporal logic reasoning about trajectories of physical systems necessitates models of time which are continuous. However, discrete time temporal logic reasoning is computationally more efficient than continuous time. Moreover, in a number of enginee ..."
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Robust Sampling for MITL Specifications Realtime temporal logic reasoning about trajectories of physical systems necessitates models of time which are continuous. However, discrete time temporal logic reasoning is computationally more efficient than continuous time. Moreover, in a number of engineering applications only discrete time models are available for analysis. In this paper, we introduce a framework for testing MITL specifications on continuous time signals using only discrete time analysis. The motivating idea behind our approach is that if the dynamics of the signal fulfills certain conditions and the discrete time signal robustly satisfies the MITL specification, then the corresponding continuous time signal should also satisfy the same MITL specification.