Seminars

  • Modeling compensations in mobile processes.

    Carla Ferreira

    Abstract: 

    We add to the asynchronous pi-calculus primitives to deal withcompensation, namely to define, store, and activated the execution of,compensations. Some simple examples illustrate the expressiveness of thelanguage. We extend the usual operational semantics (both the reductionrelation and the label transition system) with rules treating the newconstructs, and show that bisimulation is a congruence. [Joint work with António Ravara]

    Where: 
    6.3.5
    When: 
    Wednesday, July 11 2007
    Time: 
    11:00
  • Session Types for Object-Oriented Languages.

    Dimitris Mostrous

    Abstract: 

    This talk presents recent work on the integration of session types toa small concurrent Java-like calculus. A session takes place betweentwo parties; after establishing a connection, each party interleaveslocal computations with communications (sending or receiving) with theother party. Session types characterise such behaviour in terms ofthe types of values communicated and the shape of protocols, and havebeen developed for the Pi and Ambient calculi, CORBA interfaces,Haskell, multithreaded functional languages, the C language, and webdescription languages. We present the incorporation of session typesinto object-oriented languages through the language Moose, amulti-threaded language with session types, thread spawning, iterativeand higher-order sessions. We describe the design of Moose, itssyntax, operational semantics and type system, and show a number ofimportant properties of the language: type inference, type soundness,progress, and communication error freedom.[Joint work with Mariangiola Dezani (Torino), Nobuko Yoshida(Imperial), and Sophia Drossopoulou (Imperial)]

    Where: 
    6.3.5
    When: 
    Wednesday, February 28 2007
    Time: 
    11:00
  • Cryptographic primitives in a calculus with polyadic synchronisation.

    António Ravara

    Abstract: 

    We define cryptographic primitives for the pi-calculus extended with polyadic synchronisation (epi), and show that this primitivesare derivable constructs, ie, epi with cryptographic primitivesmay be fully abstractly encoded in the regular epi. The proposedencoding is sound and complete wrt barbed congruence, which, as wealso show, coincides with early bisimilarity. [Joint work with Joana Martinho and Luca Aceto]

    Where: 
    6.3.5
    When: 
    Wednesday, February 21 2007
    Time: 
    11:00
  • Comparing two approaches to compensable flow composition.

    Carla Ferreira

    Abstract: 

    In this talk it will be discussed two process algebras (cCSP andSagas) for modelling web services composition. Although both algebras arefocused on the formalisation of compensatable processes, each notationsupports a different compensation policy.

    Where: 
    6.3.5
    When: 
    Wednesday, February 7 2007
    Time: 
    11:00
  • Shared Read Access and Linear Ownership in a Typed Assembly Language.

    Francisco Martins

    Abstract: 

    We present an extended type system for a typed assembly language that allows for shared reading access to memory and that controls the linear ownership of memory tuples.

    Where: 
    6.3.5
    When: 
    Wednesday, January 24 2007
    Time: 
    11:00
  • A Stream-based Core Calculus for Services.

    Vasco T. Vasconcelos

    Abstract: 

    We present a calculus that aims at describing, in a unique framework, both individual services (and in particular the conversation between clients and servers after service invocation), and the coordination necessary to compose different services (the orchestration of concurrent and distributed services). Emphasis on the connection with Orc and with Modelling in Service-Oriented Architectures. [Joint work with Ivan Lanese, António Ravara, Francisco Martins.]

    Where: 
    6.3.5
    When: 
    Thursday, January 11 2007
    Time: 
    11:00
  • Framework Specialization Aspects.

    André Santos

    Abstract: 

    In this talk I will explain the advantages of using aspect-oriented programming (AOP) in the context of object-oriented frameworks. Variability requirements are taken into account in framework design by defining hot spots. Hot spots rely on (compositions of) design patterns. A hot spot extension implements a certain variable part in a framework specialization. I will show that this necessarily leads to code scattering/tangling in framework specializations, considering separation of concerns according to hot spot extensions. Having a framework, my approach consists in developing "specialization aspects" - abstract aspects that support a modularized interface for hot spot extension, and in turn, a modularized implementation of the hot spot extensions. Moreover, the approach evidences other benefits concerning increased reuse within specializations and lower coupling between framework and specializations. I've been carrying out a case study using the JHotDraw framework and I'll show some concrete results on applying the approach.

    Where: 
    6.3.5
    When: 
    Wednesday, July 12 2006
    Time: 
    11:00
  • Deciding Deterministic Responsiveness and Closeness in pi-calculus.

    Maxime Gamboni

    Abstract: 

    I'll describe a type system for data structure encodings in pi, thatchecks process parts storing encoded data so that a decoding requestis replied once, deterministically, uniformly and without side effects.

    Where: 
    6.3.5
    When: 
    Wednesday, June 28 2006
    Time: 
    11:00
  • Extensionality of Spatial Observations in Distributed Systems.

    Hugo Torres Vieira

    Abstract: 

    We discuss the tensions between intensionality and extensionalityof spatial observations in distributed systems, showing that thereare models where observational equivalences may be characterizedby spatial logics, including the composition and void operators. Ourresults support the claim that spatial observations do not need to bealways considered intensional, even if expressive enough to talkabout the stucture of systems. [Joint work with Luís Caires]

    Where: 
    6.3.5
    When: 
    Wednesday, June 21 2006
    Time: 
    11:00
  • A Formal Approach to Service Component Architectures.

    Antónia Lopes

    Abstract: 

    In this talk I will report on an algebraic framework being developed within the SENSORIA project for supporting service-oriented modelling at high levels of abstraction, i.e. independently of the hosting middleware and hardware platforms, and the languages in which services are programmed. More specifically, I will give an account of the notion of module that supports the composition model of SENSORIA, which includes interfaces for required (imported) and provided (exported) services, as well as a number of components (body) whose orchestrations ensure how given behavioural properties of the provided services are guaranteed assuming that the requested services satisfy required properties. [Joint work with José Fiadeiro and Laura Bocchi]

    Where: 
    6.3.5
    When: 
    Wednesday, June 7 2006
    Time: 
    11:00

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