João Abreu | ESMAE - Academia.edu (original) (raw)

Papers by João Abreu

Research paper thumbnail of Conclusiones de las V Jornadas Luso-Españolas de Terapia Manual

Revista Iberoamericana de Fisioterapia y Kinesiología, 2007

Conclusiones de las V Jornadas Luso-Españolas de Terapia Manual.

Research paper thumbnail of O desenvolvimento da proficiência motora em crianças ciganas e não ciganas: um estudo comparativo

Motricidade, 2007

O objectivo deste trabalho foi o de estudar possíveis infl uências da etnia sobre o desenvolvimen... more O objectivo deste trabalho foi o de estudar possíveis infl uências da etnia sobre o desenvolvimento motor. Para tal foi constituída uma amostra de 60 crianças de ambos os géneros com 7, 8 e 9 anos de idade: 30 crianças ciganas que frequentavam uma escola do 1º ciclo em Moura; 30 crianças não ciganas que frequentavam uma escola do 1º ciclo em Lisboa. Para estudo e comparação dos níveis de desenvolvimento motor dos dois grupos da amostra, foi utilizada a forma reduzida do Teste de Profi ciência Motora de Bruininks-Oseretsky. Concluiu-se que as crianças não ciganas em comparação com crianças de etnia cigana, apresentavam valores signifi cativamente superiores da motricidade global (p=0,015), da motricidade fi na (p=0,000) e da própria profi ciência motora (p=0,005).

Research paper thumbnail of Exact conformal scalar field cosmologies

Classical and Quantum Gravity, 1994

New exact solutions of Einstein's gravity coupled to a self-interacting conformal scalar field ar... more New exact solutions of Einstein's gravity coupled to a self-interacting conformal scalar field are derived in this work. Our approach extends a solution-generating technique originally introduced by Bekenstein for massless conformal scalar fields. Solutions are obtained for a Friedmann-Robertson-Walker geometry both for the cases of zero and non-zero curvatures, and a variety of interesting features are found. It is shown that one class of solutions tends asymptotically to a power-law inflationary behaviour S(t) ∼ t p with p > 1, while another class exhibits a late time approach to the S(t) ∼ t behaviour of the coasting models. Bouncing models which avoid an initial singularity are also obtained. A general discussion of the asymptotic behaviour and of the possibility of occurrence of inflation is provided.

Research paper thumbnail of Business Processes Improvement on Maintenance Management: A Case Study

Procedia Technology, 2013

The adoption of business process improvement strateg approaches to quality and service improvemen... more The adoption of business process improvement strateg approaches to quality and service improvement and optimization enables organizations to achieve business ob in achieving the goal of improving overall efficiency in th avoiding costly downtime. However, there have bee management. This paper presents a case study about main an airport.

Research paper thumbnail of Vapor−Liquid Equilibria Data for Binary Systems of Ethylbenzene + Xylene Isomers at 100.65 kPa

Journal of Chemical and Engineering Data, 2005

Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained is... more Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained isobarically with a modified Fischer cell at 100.65 kPa. Temperatures were measured with a resolution of (0.001 K, and vapor-and liquid-phase compositions were analyzed with a gas chromatograph. The data obtained were considered to be thermodynamically consistent according to the Van Ness and Fredenslund test. Pure vapor pressures for the compounds are also reported. Interaction parameters for the most used activity coefficient models and cubic equations were obtained through data fitting performed with Aspen Plus 10.1.

Research paper thumbnail of Vapor−Liquid Equilibria Data for Binary Systems of Ethylbenzene + Xylene Isomers at 100.65 kPa

Journal of Chemical & Engineering Data, 2005

Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained is... more Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained isobarically with a modified Fischer cell at 100.65 kPa. Temperatures were measured with a resolution of (0.001 K, and vapor-and liquid-phase compositions were analyzed with a gas chromatograph. The data obtained were considered to be thermodynamically consistent according to the Van Ness and Fredenslund test. Pure vapor pressures for the compounds are also reported. Interaction parameters for the most used activity coefficient models and cubic equations were obtained through data fitting performed with Aspen Plus 10.1.

Research paper thumbnail of Specifying and Composing Interaction Protocols for Service-Oriented System Modelling

Lecture Notes in Computer Science, 2007

We present and discuss a formal, high-level approach to the specification and composition of inte... more We present and discuss a formal, high-level approach to the specification and composition of interaction protocols for service-oriented systems. This work is being developed within the SENSORIA project as part of a language and formal framework supporting the modelling of complex services at the business level, i.e. independent of the underlying platform and the languages in which services are programmed and deployed. Our approach is based on a novel language and logic of interactions, and a mathematical semantics of composition based on graphs. We illustrate our approach using a case study provided by Telecom Italia, one of our industrial partners in the project.

Research paper thumbnail of A Formal Approach to Modelling Time Properties of Service-Oriented Systems?

We provide a formal model for expressing and analysing time-related properties of service-oriente... more We provide a formal model for expressing and analysing time-related properties of service-oriented systems. Our approach extends SRML, a high-level modelling language that we have been developing in the SENSORIA project. We introduce new primitives for SRML that capture several kinds of delays that can occur during service provision (e.g., the time taken by components to process events and perform computations, the time taken by the SOA middleware for discovering, selecting and binding services, etc.). Finally, we show how we can use the stochastic process algebra PEPA and its development environment to represent and analyse time properties of SRML models.

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Lecture Notes in Computer Science, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.

Research paper thumbnail of Specifying and Composing Interaction Protocols for Service-Oriented System Modelling

Lecture Notes in Computer Science, 2007

We present and discuss a formal, high-level approach to the specification and composition of inte... more We present and discuss a formal, high-level approach to the specification and composition of interaction protocols for service-oriented systems. This work is being developed within the SENSORIA project as part of a language and formal framework supporting the modelling of complex services at the business level, i.e. independent of the underlying platform and the languages in which services are programmed and deployed. Our approach is based on a novel language and logic of interactions, and a mathematical semantics of composition based on graphs. We illustrate our approach using a case study provided by Telecom Italia, one of our industrial partners in the project.

Research paper thumbnail of Analysing Time-Related Properties of Service-Oriented Systems

Research paper thumbnail of A Formal Approach to Modelling Time Properties of Service-Oriented Systems?

We provide a formal model for expressing and analysing time-related properties of service-oriente... more We provide a formal model for expressing and analysing time-related properties of service-oriented systems. Our approach extends SRML, a high-level modelling language that we have been developing in the SENSORIA project. We introduce new primitives for SRML that capture several kinds of delays that can occur during service provision (e.g., the time taken by components to process events and perform computations, the time taken by the SOA middleware for discovering, selecting and binding services, etc.). Finally, we show how we can use the stochastic process algebra PEPA and its development environment to represent and analyse time properties of SRML models.

Research paper thumbnail of The Sensoria Reference Modelling Language

Lecture Notes in Computer Science, 2011

This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus w... more This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus will be on the language primitives that SRML offers for modelling business services and activities, the methodological approach that SRML supports, and the mathematical semantics the underpins the modelling approach, including techniques for qualitative and quantitative analysis. CarolEstAg MyRegistry AliceManag RockLoans BobMortAg BCL CarolMortAg Law4All CEL BobEstateUI AliceRegUI ARM BCR AMR CarolEstateUI CEA CCR CEM BobEstAg BEA BAM Fig. 27. The graph of a state configuration with 11 components and 10 wires.

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Lecture Notes in Computer Science, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.

Research paper thumbnail of Testing Implementations of Algebraic Specifications with Design-by-Contract Tools

IEEE Transactions on Reliability, 2005

We present an approach for testing Java implementations of abstract data types (ADTs) against the... more We present an approach for testing Java implementations of abstract data types (ADTs) against their specifications. The key idea is to reduce this problem to the run-time monitoring of contract annotated classes, which is supported today by several runtime assertion-checking tools. The approach comprises an ADT specification language that allows automatic generation of monitorable contracts and a refinement language that supports the specification of the details of object-oriented implementations of ADTs. design time implementation time Specification Module T

Research paper thumbnail of Analysing Time-Related Properties of Service-Oriented Systems

Research paper thumbnail of A Model-Checking Approach for Service Component Architectures

Formal Techniques for Networked and Distributed Systems, 2009

We present a strategy for model-checking the correctness of service composition. We do so in the ... more We present a strategy for model-checking the correctness of service composition. We do so in the context of SRML, a formal modelling framework for service-oriented computing being defined within the SENSORIA project. We introduce a methodology for encoding patterns of typical service interaction with UML state machines and present a strategy for checking SRML specifications of service composition based on such patterns. For that purpose, we use the action-state branching time temporal logic UCTL and the model-checker UMC.

Research paper thumbnail of The Sensoria Reference Modelling Language

Lecture Notes in Computer Science, 2011

This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus w... more This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus will be on the language primitives that SRML offers for modelling business services and activities, the methodological approach that SRML supports, and the mathematical semantics the underpins the modelling approach, including techniques for qualitative and quantitative analysis. CarolEstAg MyRegistry AliceManag RockLoans BobMortAg BCL CarolMortAg Law4All CEL BobEstateUI AliceRegUI ARM BCR AMR CarolEstateUI CEA CCR CEM BobEstAg BEA BAM Fig. 27. The graph of a state configuration with 11 components and 10 wires.

Research paper thumbnail of Testing Implementations of Algebraic Specifications with Design-by-Contract Tools

IEEE Transactions on Reliability, 2005

We present an approach for testing Java implementations of abstract data types (ADTs) against the... more We present an approach for testing Java implementations of abstract data types (ADTs) against their specifications. The key idea is to reduce this problem to the run-time monitoring of contract annotated classes, which is supported today by several runtime assertion-checking tools. The approach comprises an ADT specification language that allows automatic generation of monitorable contracts and a refinement language that supports the specification of the details of object-oriented implementations of ADTs. design time implementation time Specification Module T

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Coordination Models and Languages, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.

Research paper thumbnail of Conclusiones de las V Jornadas Luso-Españolas de Terapia Manual

Revista Iberoamericana de Fisioterapia y Kinesiología, 2007

Conclusiones de las V Jornadas Luso-Españolas de Terapia Manual.

Research paper thumbnail of O desenvolvimento da proficiência motora em crianças ciganas e não ciganas: um estudo comparativo

Motricidade, 2007

O objectivo deste trabalho foi o de estudar possíveis infl uências da etnia sobre o desenvolvimen... more O objectivo deste trabalho foi o de estudar possíveis infl uências da etnia sobre o desenvolvimento motor. Para tal foi constituída uma amostra de 60 crianças de ambos os géneros com 7, 8 e 9 anos de idade: 30 crianças ciganas que frequentavam uma escola do 1º ciclo em Moura; 30 crianças não ciganas que frequentavam uma escola do 1º ciclo em Lisboa. Para estudo e comparação dos níveis de desenvolvimento motor dos dois grupos da amostra, foi utilizada a forma reduzida do Teste de Profi ciência Motora de Bruininks-Oseretsky. Concluiu-se que as crianças não ciganas em comparação com crianças de etnia cigana, apresentavam valores signifi cativamente superiores da motricidade global (p=0,015), da motricidade fi na (p=0,000) e da própria profi ciência motora (p=0,005).

Research paper thumbnail of Exact conformal scalar field cosmologies

Classical and Quantum Gravity, 1994

New exact solutions of Einstein's gravity coupled to a self-interacting conformal scalar field ar... more New exact solutions of Einstein's gravity coupled to a self-interacting conformal scalar field are derived in this work. Our approach extends a solution-generating technique originally introduced by Bekenstein for massless conformal scalar fields. Solutions are obtained for a Friedmann-Robertson-Walker geometry both for the cases of zero and non-zero curvatures, and a variety of interesting features are found. It is shown that one class of solutions tends asymptotically to a power-law inflationary behaviour S(t) ∼ t p with p > 1, while another class exhibits a late time approach to the S(t) ∼ t behaviour of the coasting models. Bouncing models which avoid an initial singularity are also obtained. A general discussion of the asymptotic behaviour and of the possibility of occurrence of inflation is provided.

Research paper thumbnail of Business Processes Improvement on Maintenance Management: A Case Study

Procedia Technology, 2013

The adoption of business process improvement strateg approaches to quality and service improvemen... more The adoption of business process improvement strateg approaches to quality and service improvement and optimization enables organizations to achieve business ob in achieving the goal of improving overall efficiency in th avoiding costly downtime. However, there have bee management. This paper presents a case study about main an airport.

Research paper thumbnail of Vapor−Liquid Equilibria Data for Binary Systems of Ethylbenzene + Xylene Isomers at 100.65 kPa

Journal of Chemical and Engineering Data, 2005

Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained is... more Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained isobarically with a modified Fischer cell at 100.65 kPa. Temperatures were measured with a resolution of (0.001 K, and vapor-and liquid-phase compositions were analyzed with a gas chromatograph. The data obtained were considered to be thermodynamically consistent according to the Van Ness and Fredenslund test. Pure vapor pressures for the compounds are also reported. Interaction parameters for the most used activity coefficient models and cubic equations were obtained through data fitting performed with Aspen Plus 10.1.

Research paper thumbnail of Vapor−Liquid Equilibria Data for Binary Systems of Ethylbenzene + Xylene Isomers at 100.65 kPa

Journal of Chemical & Engineering Data, 2005

Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained is... more Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained isobarically with a modified Fischer cell at 100.65 kPa. Temperatures were measured with a resolution of (0.001 K, and vapor-and liquid-phase compositions were analyzed with a gas chromatograph. The data obtained were considered to be thermodynamically consistent according to the Van Ness and Fredenslund test. Pure vapor pressures for the compounds are also reported. Interaction parameters for the most used activity coefficient models and cubic equations were obtained through data fitting performed with Aspen Plus 10.1.

Research paper thumbnail of Specifying and Composing Interaction Protocols for Service-Oriented System Modelling

Lecture Notes in Computer Science, 2007

We present and discuss a formal, high-level approach to the specification and composition of inte... more We present and discuss a formal, high-level approach to the specification and composition of interaction protocols for service-oriented systems. This work is being developed within the SENSORIA project as part of a language and formal framework supporting the modelling of complex services at the business level, i.e. independent of the underlying platform and the languages in which services are programmed and deployed. Our approach is based on a novel language and logic of interactions, and a mathematical semantics of composition based on graphs. We illustrate our approach using a case study provided by Telecom Italia, one of our industrial partners in the project.

Research paper thumbnail of A Formal Approach to Modelling Time Properties of Service-Oriented Systems?

We provide a formal model for expressing and analysing time-related properties of service-oriente... more We provide a formal model for expressing and analysing time-related properties of service-oriented systems. Our approach extends SRML, a high-level modelling language that we have been developing in the SENSORIA project. We introduce new primitives for SRML that capture several kinds of delays that can occur during service provision (e.g., the time taken by components to process events and perform computations, the time taken by the SOA middleware for discovering, selecting and binding services, etc.). Finally, we show how we can use the stochastic process algebra PEPA and its development environment to represent and analyse time properties of SRML models.

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Lecture Notes in Computer Science, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.

Research paper thumbnail of Specifying and Composing Interaction Protocols for Service-Oriented System Modelling

Lecture Notes in Computer Science, 2007

We present and discuss a formal, high-level approach to the specification and composition of inte... more We present and discuss a formal, high-level approach to the specification and composition of interaction protocols for service-oriented systems. This work is being developed within the SENSORIA project as part of a language and formal framework supporting the modelling of complex services at the business level, i.e. independent of the underlying platform and the languages in which services are programmed and deployed. Our approach is based on a novel language and logic of interactions, and a mathematical semantics of composition based on graphs. We illustrate our approach using a case study provided by Telecom Italia, one of our industrial partners in the project.

Research paper thumbnail of Analysing Time-Related Properties of Service-Oriented Systems

Research paper thumbnail of A Formal Approach to Modelling Time Properties of Service-Oriented Systems?

We provide a formal model for expressing and analysing time-related properties of service-oriente... more We provide a formal model for expressing and analysing time-related properties of service-oriented systems. Our approach extends SRML, a high-level modelling language that we have been developing in the SENSORIA project. We introduce new primitives for SRML that capture several kinds of delays that can occur during service provision (e.g., the time taken by components to process events and perform computations, the time taken by the SOA middleware for discovering, selecting and binding services, etc.). Finally, we show how we can use the stochastic process algebra PEPA and its development environment to represent and analyse time properties of SRML models.

Research paper thumbnail of The Sensoria Reference Modelling Language

Lecture Notes in Computer Science, 2011

This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus w... more This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus will be on the language primitives that SRML offers for modelling business services and activities, the methodological approach that SRML supports, and the mathematical semantics the underpins the modelling approach, including techniques for qualitative and quantitative analysis. CarolEstAg MyRegistry AliceManag RockLoans BobMortAg BCL CarolMortAg Law4All CEL BobEstateUI AliceRegUI ARM BCR AMR CarolEstateUI CEA CCR CEM BobEstAg BEA BAM Fig. 27. The graph of a state configuration with 11 components and 10 wires.

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Lecture Notes in Computer Science, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.

Research paper thumbnail of Testing Implementations of Algebraic Specifications with Design-by-Contract Tools

IEEE Transactions on Reliability, 2005

We present an approach for testing Java implementations of abstract data types (ADTs) against the... more We present an approach for testing Java implementations of abstract data types (ADTs) against their specifications. The key idea is to reduce this problem to the run-time monitoring of contract annotated classes, which is supported today by several runtime assertion-checking tools. The approach comprises an ADT specification language that allows automatic generation of monitorable contracts and a refinement language that supports the specification of the details of object-oriented implementations of ADTs. design time implementation time Specification Module T

Research paper thumbnail of Analysing Time-Related Properties of Service-Oriented Systems

Research paper thumbnail of A Model-Checking Approach for Service Component Architectures

Formal Techniques for Networked and Distributed Systems, 2009

We present a strategy for model-checking the correctness of service composition. We do so in the ... more We present a strategy for model-checking the correctness of service composition. We do so in the context of SRML, a formal modelling framework for service-oriented computing being defined within the SENSORIA project. We introduce a methodology for encoding patterns of typical service interaction with UML state machines and present a strategy for checking SRML specifications of service composition based on such patterns. For that purpose, we use the action-state branching time temporal logic UCTL and the model-checker UMC.

Research paper thumbnail of The Sensoria Reference Modelling Language

Lecture Notes in Computer Science, 2011

This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus w... more This chapter provides an overview of SRML -the Sensoria Reference Modelling Language. Our focus will be on the language primitives that SRML offers for modelling business services and activities, the methodological approach that SRML supports, and the mathematical semantics the underpins the modelling approach, including techniques for qualitative and quantitative analysis. CarolEstAg MyRegistry AliceManag RockLoans BobMortAg BCL CarolMortAg Law4All CEL BobEstateUI AliceRegUI ARM BCR AMR CarolEstateUI CEA CCR CEM BobEstAg BEA BAM Fig. 27. The graph of a state configuration with 11 components and 10 wires.

Research paper thumbnail of Testing Implementations of Algebraic Specifications with Design-by-Contract Tools

IEEE Transactions on Reliability, 2005

We present an approach for testing Java implementations of abstract data types (ADTs) against the... more We present an approach for testing Java implementations of abstract data types (ADTs) against their specifications. The key idea is to reduce this problem to the run-time monitoring of contract annotated classes, which is supported today by several runtime assertion-checking tools. The approach comprises an ADT specification language that allows automatic generation of monitorable contracts and a refinement language that supports the specification of the details of object-oriented implementations of ADTs. design time implementation time Specification Module T

Research paper thumbnail of A Coordination Model for Service-Oriented Interactions

Coordination Models and Languages, 2008

We present a formal model for the coordination of interactions in service-oriented systems. This ... more We present a formal model for the coordination of interactions in service-oriented systems. This model provides a declarative semantics for the language SRML that is being developed under the FET-GC2 project SENSORIA for modelling and reasoning about complex services at the abstract business level. In SRML, interactions are conversational in the sense that they involve a number of correlated events that capture phenomena that are typical of SOC like committing to a pledge or revoking the effects of a deal. Events are exchanged across wires that connect the parties involved in the provision of the service.