31 research outputs found

    Women out, children out : the effect of female labor on portuguese preschool enrollment rates

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    This article tests whether Portuguese female activity rates have increased preschool enrollment rates. Particularly during the last 20 years, Portuguese women have assumed new roles in the marketplace and have become active workers outside of the home environment. This change has encouraged more sensible decisions with respect to preschool enrollment. Using cointegration techniques, we concluded that female activity rates and real income per capita caused a long-term increase in preschool enrollment rates. Although the percentage of agricultural gross value added to the gross domestic product and the number of preschool institutes were also found to be significant in the estimated vector error correction model, their causal relationship with preschool enrollment was only short term.COMPETE; QREN; FEDER; Fundação para a Ciência e a Tecnologia (FCT

    Existential abstractions for distributed reactive systems via syntactic transformations

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    Synchronous languages are well suited to implementation and verification of reactive systems. Large reactive systems tend to be distributed to cope with scalability and application specific demands. We propose abstractions for distributed reactive systems modelled as a set of synchronous nodes with asynchronous communication between them. The special features of synchronous programs allow us to obtain abstractions that are also valid synchronous programs only by syntactic transformations. For a given program, the set of all such abstractions forms a semi-lattice with the original program as the bottom and the most abstract program as the top element. The transformation we define is a natural basis for constructing an abstraction-refinement framework for verification. Given a program and a safety property, the abstraction-refinement process is a search in a lattice of programs obtained via syntactic transformations. We have implemented this abstraction refinement framework in a prototype tool and report our case studies

    Existential abstractions for distributed reactive systems via syntactic transformations

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    Synchronous languages are well suited to implementation and verification of reactive systems. Large reactive systems tend to be distributed to cope with scalability and application specific demands. We propose abstractions for distributed reactive systems modelled as a set of synchronous nodes with asynchronous communication between them. The special features of synchronous programs allow us to obtain abstractions that are also valid synchronous programs only by syntactic transformations. For a given program, the set of all such abstractions forms a semi-lattice with the original program as the bottom and the most abstract program as the top element. The transformation we define is a natural basis for constructing an abstraction-refinement framework for verification. Given a program and a safety property, the abstraction-refinement process is a search in a lattice of programs obtained via syntactic transformations. We have implemented this abstraction refinement framework in a prototype tool and report our case studies

    A Toolset for Modelling and Verification of GALS Systems

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