92 research outputs found
A Benchmarks Library for Extended Parametric Timed Automata
Parametric timed automata are a powerful formalism for reasoning on
concurrent real-time systems with unknown or uncertain timing constants. In
order to test the efficiency of new algorithms, a fair set of benchmarks is
required. We present an extension of the IMITATOR benchmarks library, that
accumulated over the years a number of case studies from academic and
industrial contexts. We extend here the library with several dozens of new
benchmarks; these benchmarks highlight several new features: liveness
properties, extensions of (parametric) timed automata (including stopwatches or
multi-rate clocks), and unsolvable toy benchmarks. These latter additions help
to emphasize the limits of state-of-the-art parameter synthesis techniques,
with the hope to develop new dedicated algorithms in the future.Comment: This is the author (and extended) version of the manuscript of the
same name published in the proceedings of the 15th International Conference
on Tests and Proofs (TAP 2021
Architectures in parametric component-based systems: Qualitative and quantitative modelling
One of the key aspects in component-based design is specifying the software
architecture that characterizes the topology and the permissible interactions
of the components of a system. To achieve well-founded design there is need to
address both the qualitative and non-functional aspects of architectures. In
this paper we study the qualitative and quantitative formal modelling of
architectures applied on parametric component-based systems, that consist of an
unknown number of instances of each component. Specifically, we introduce an
extended propositional interaction logic and investigate its first-order level
which serves as a formal language for the interactions of parametric systems.
Our logics achieve to encode the execution order of interactions, which is a
main feature in several important architectures, as well as to model recursive
interactions. Moreover, we prove the decidability of equivalence,
satisfiability, and validity of first-order extended interaction logic
formulas, and provide several examples of formulas describing well-known
architectures. We show the robustness of our theory by effectively extending
our results for parametric weighted architectures. For this, we study the
weighted counterparts of our logics over a commutative semiring, and we apply
them for modelling the quantitative aspects of concrete architectures. Finally,
we prove that the equivalence problem of weighted first-order extended
interaction logic formulas is decidable in a large class of semirings, namely
the class (of subsemirings) of skew fields.Comment: 53 pages, 11 figure
Process Algebraic Approach to the Schedulability Analysis and Workload Abstraction of Hierarchical Real-Time Systems
Real-time embedded systems have increased in complexity. As microprocessors become more powerful, the software complexity of real-time embedded systems has increased steadily. The requirements for increased functionality and adaptability make the development of real-time embedded software complex and error-prone. Component-based design has been widely accepted as a compositional approach to facilitate the design of complex systems. It provides a means for decomposing a complex system into simpler subsystems and composing the subsystems in a hierarchical manner. A system composed of real-time subsystems with hierarchy is called a hierarchical real-time system
This paper describes a process algebraic approach to schedulability analysis of hierarchical real-time systems. To facilitate modeling and analyzing hierarchical real-time systems, we conservatively extend an existing process algebraic theory based on ACSR-VP (Algebra of Communicating Shared Resources with Value-Passing) for the schedulability of real-time systems. We explain a method to model a resource model in ACSR-VP which may be partitioned for a subsystem. We also introduce schedulability relation to define the schedulability of hierarchical real-time systems and show that satisfaction checking of the relation is reducible to deadlock checking in ACSR-VP and can be done automatically by the tool support of ERSA (Verification, Execution and Rewrite System for ACSR). With the schedulability relation, we present algorithms for abstracting real-time system workloads
Classification-based parameter synthesis for parametric timed automata
National Research Foundation (NRF) Singapor
Engineering Trustworthy Self-Adaptive Software with Dynamic Assurance Cases
Building on concepts drawn from control theory, self-adaptive software handles environmental and internal uncertainties by dynamically adjusting its architecture and parameters in response to events such as workload changes and component failures. Self-adaptive software is increasingly expected to meet strict functional and non-functional requirements in applications from areas as diverse as manufacturing, healthcare and finance. To address this need, we introduce a methodology for the systematic ENgineering of TRUstworthy Self-adaptive sofTware (ENTRUST). ENTRUST uses a combination of (1) design-time and runtime modelling and verification, and (2) industry-adopted assurance processes to develop trustworthy self-adaptive software and assurance cases arguing the suitability of the software for its intended application. To evaluate the effectiveness of our methodology, we present a tool-supported instance of ENTRUST and its use to develop proof-of-concept self-adaptive software for embedded and service-based systems from the oceanic monitoring and e-finance domains, respectively. The experimental results show that ENTRUST can be used to engineer self-adaptive software systems in different application domains and to generate dynamic assurance cases for these systems
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