140 research outputs found
Composing Families of Timed Automata
Featured Timed Automata (FTA) is a formalism that enables the verification of an entire Software Product Line (SPL), by capturing its behavior in a single model instead of product-by-product. However, it disregards compositional aspects inherent to SPL development. This paper introduces Interface FTA (IFTA), which extends FTA with variable interfaces that restrict the way automata can be composed, and with support for transitions with atomic multiple actions, simplifying the design. To support modular composition, a set of Reo connectors are modelled as IFTA. This separation of concerns increases reusability of functionality across products, and simplifies modelling, maintainability, and extension of SPLs. We show how IFTA can be easily translated into FTA and into networks of Timed Automata supported by UPPAAL. We illustrate this with a case study from the electronic government domain.POCI-01-0145-FEDER-016826. NORTE-01-0145-FEDER-00003
Modeling component connectors in Reo by constraint automata
Reo is an exogenous coordination language for compositional construction of component connectors based on a calculus of channels. Building automated tools to address such concerns as equivalence or containment of the behavior of two given connectors, verification of the behavior of a connector, etc. requires an operational semantic model suitable for model checking. In this paper we introduce constraint automata and propose them as a semantic model for Reo
Modeling component connectors in Reo by constraint automata
Reo is an exogenous coordination language for compositional construction of component connectors based on a calculus of channels. Building automated tools to address such concerns as equivalence or containment of the behavior of two given connectors, verification of the behavior of a connector, etc. requires an operational semantic model suitable for model checking. In this paper we introduce constraint automata and propose them as a semantic model for Reo
Handshaking Protocol for Distributed Implementation of Reo
Reo, an exogenous channel-based coordination language, is a model for service
coordination wherein services communicate through connectors formed by joining
binary communication channels. In order to establish transactional
communication among services as prescribed by connector semantics, distributed
ports exchange handshaking messages signalling which parties are ready to
provide or consume data. In this paper, we present a formal implementation
model for distributed Reo with communication delays and outline ideas for its
proof of correctness. To reason about Reo implementation formally, we introduce
Timed Action Constraint Automata (TACA) and explain how to compare TACA with
existing automata-based semantics for Reo. We use TACA to describe handshaking
behavior of Reo modeling primitives and argue that in any distributed circuit
remote Reo nodes and channels exposing such behavior commit to perform
transitions envisaged by the network semantics.Comment: In Proceedings FOCLASA 2014, arXiv:1502.0315
Reo + mCRL2: A Framework for Model-Checking Dataflow in Service Compositions
The paradigm of service-oriented computing revolutionized the field of software
engineering. According to this paradigm, new systems are composed of existing
stand-alone services to support complex cross-organizational business
processes. Correct communication of these services is not possible without a
proper coordination mechanism. The Reo coordination language is a channel-based
modeling language that introduces various types of channels and their
composition rules. By composing Reo channels, one can specify Reo connectors
that realize arbitrary complex behavioral protocols. Several formalisms have
been introduced to give semantics to Reo. In their most basic form, they
reflect service synchronization and dataflow constraints imposed by connectors.
To ensure that the composed system behaves as intended, we need a wide range of
automated verification tools to assist service composition designers. In this
paper, we present our framework for the verification of Reo using the mCRL2
toolset. We unify our previous work on mapping various semantic models for Reo,
namely, constraint automata, timed constraint automata, coloring semantics and
the newly developed action constraint automata, to the process algebraic
specification language of mCRL2, address the correctness of this mapping,
discuss tool support, and present a detailed example that illustrates the use
of Reo empowered with mCRL2 for the analysis of dataflow in service-based
process models
Reo + mCRL2: A Framework for Model-checking Dataflow in Service Compositions
The paradigm of service-oriented computing revolutionized the field of software engineering. According to this paradigm, new systems are composed of existing stand-alone services to support complex cross-organizational business processes. Correct communication of these services is not possible without a proper coordination mechanism. The Reo coordination language is a channel-based modeling language that introduces various types of channels and their composition rules. By composing Reo channels, one can specify Reo connectors that realize arbitrary complex behavioral protocols. Several formalisms have been introduced to give semantics to Reo. In their most basic form, they reflect service synchronization and dataflow constraints imposed by connectors. To ensure that the composed system behaves as intended, we need a wide range of automated verification tools to assist service composition designers. In this paper, we present our framework for the verification of Reo using the toolset. We unify our previous work on mapping various semantic models for Reo, namely, constraint automata, timed constraint automata, coloring semantics and the newly developed action constraint automata, to the process algebraic specification language of , address the correctness of this mapping, discuss tool support, and present a detailed example that illustrates the use of Reo empowered with for the analysis of dataflow in service-based process models
Compositional Construction of Real-Time Dataflow Networks
Increasing sizes of present-day distributed software systems call for
coordination models which are both \emph{modular} and \emph{scalable}.
Precise modelling of real-life applications further requires the notion of
\emph{real-time}.
In this paper, we present a modular formal development of a compositional model
for real-time coordination in dataflow networks. While real-time dataflow
networks are typically asynchronous, our approach includes coordination
patterns which combine, but are not limited to, synchrony and asynchrony. We
define a constraint- and SAT-based encoding, which allows us to benefit
from high-end constraint solving techniques when inspecting valid interactions
of the system
A virtual factory for smart city service integration
Tese de Doutoramento em Informática (MAP-i)In the context of smart cities, governments are investing efforts on creating public
value through the development of digital public services (DPS) focusing on specific
policy areas, such as transport. Main motivations to deliver DPS include reducing
administrative burdens and costs, increasing effectiveness and efficiency of government
processes, and improving citizens’ quality of life through enhanced services and simplified
interactions with governments.
To ensure effective planning and design of DPS in a given domain, governments face
several challenges, like the need of specialized tools to facilitate the effective planning
and the rapid development of DPS, as well as, tools for service integration, affording
high development costs, and ensuring DPS conform with laws and regulations.
These challenges are exacerbated by the fact that many public administrations develop
tailored DPS, disregarding the fact that services share common functionality
and business processes.
To address the above challenges, this thesis focuses on leveraging the similarities of
DPS and on applying a Software Product Line (SPL) approach combined with formal
methods techniques for specifying service models and verifying their behavioural properties.
In particular, the proposed solution introduces the concept of a virtual factory
for the planning and rapid development of DPS in a given smart city domain. The
virtual factory comprises a framework including software tools, guidelines, practices,
models, and other artefacts to assist engineers to automate and make more efficient
the development of a family of DPS.
In this work the virtual factory is populated with tools for government officials and
software developers to plan and design smart mobility services, and to rapidly model
DPS relying on SPLs and components-base development techniques.
Specific contributions of the thesis include: 1) the concept of virtual factory; 2)
a taxonomy for planning and designing smart mobility services; 3) an ontology to fix
a common vocabulary for a specific family of DPS; 4) a compositional formalism to
model SPLs, to serve as a specification language for DPS; and 5) a variable semantics
for a coordination language to simplify coordination of services in the context of SPLs.No contexto das cidades inteligentes, os governos investem esforços na criação de valor
público através do desenvolvimento de serviços públicos digitais (DPS), concentrandose
em áreas políticas específicas, como os transportes. As principais motivações para
entregar o DPS incluem a redução de custos administrativos, o aumento da eficácia
dos processos do governo e a melhoria da qualidade de vida dos cidadãos através de
serviços melhorados e interações simplificadas com os governos.
Para garantir um planeamento efetivo do DPS num determinado domínio, os governos
enfrentam vários desafios, como a necessidade de ferramentas especializadas para
facilitar o planeamento eficaz e o rápido desenvolvimento do DPS, bem como ferramentas
para integração de DPS, reduzindo altos custos de desenvolvimento e garantindo
que os DPS estejam em conformidade com as leis e regulamentos.
Esses desafios são exacerbados pelo fato de que muitas administrações públicas
desenvolvem o DPS sob medida, desconsiderando o fato de que os serviços compartilham
funcionalidade e processos de negócios comuns.
Para enfrentar os desafios, esta tese concentra-se em aproveitar as semelhanças dos
DPS aplicando uma abordagem de Software Product Lines (SPL) combinada com métodos
formais para especificar modelos de DPS e verificar propriedades. Em particular,
introduz o conceito de uma fábrica virtual (VF) para o planeamento e desenvolvimento
rápido de DPS num domínio de cidade inteligente. A VF compreende ferramentas de
software, diretrizes, modelos e outros artefatos para auxiliar os engenheiros a automatizar
e tornar mais eficiente o desenvolvimento de uma família de DPS.
Neste trabalho, a VF é preenchida com ferramentas para várias partes para planear
e projetar serviços de mobilidade inteligente (MI), e modelar rapidamente o DPS com
base em SPLs e técnicas de desenvolvimento baseadas em componentes.
Contribuições específicas da tese incluem: 1) o conceito de VF; 2) uma taxonomia
para planear serviços de MI; 3) uma ontologia para fixar um vocabulário comum para
uma família específica de DPS; 4) um formalismo composicional para modelar SPLs,
e servir como uma linguagem de especificação para DPS; e 5) uma semântica variável
para uma linguagem de coordenação para simplificar a coordenação.This work was funded by FCT – Foundation for Science and Technology, the Portuguese Ministry of Science, Technology and Higher Education, through the Operational Programme for Human Capital (POCH). Grant reference: PD/BD/52238/201
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