Research in embedded networked sensing has primarily focused on the design of hardware architectures for sensor nodes and infrastructure protocols for long lived operation of resource constrained sensor network deploy...
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Based on our experience in implementing a type-checker for the Object Constraint Language (OCL), we observed that OCL is not suitable for constraining a system under development, because changes in the underlying clas...
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ISBN:
(纸本)3540261818
Based on our experience in implementing a type-checker for the Object Constraint Language (OCL), we observed that OCL is not suitable for constraining a system under development, because changes in the underlying class diagram unnecessarily invalidate the type correctness of constraints, while their semantic value does not change. Furthermore, the type system of OCL does not support templates. To alleviate these problems, we extended the type system of OCL with intersection and union types and bounded operator abstraction. the main advantage of our type system is that it allows more changes in the contextual class diagrams without adapting the OCL constraints.
alpha Prolog is a logic programming language which is well-suited for rapid prototyping of type systems and operational semantics of typed A-calculi and many other languages involving bound names. In alpha Prolog, the...
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ISBN:
(数字)9783540320142
ISBN:
(纸本)3540255931
alpha Prolog is a logic programming language which is well-suited for rapid prototyping of type systems and operational semantics of typed A-calculi and many other languages involving bound names. In alpha Prolog, the nominal unification algorithm of Urban, Pitts and Gabbay is used instead of first-order unification. However, although alpha Prolog can be viewed as Horn-clause logic programming in Pitts' nominal logic, proof search using nominal unification is incomplete in nominal logic. Because of nominal logic's equivariance principle, complete proof search would require solving NP-hard equivariant unification problems. Nevertheless, the alpha Prolog programs we studied run correctly without equivariant unification. In this paper, we give several examples of alpha Prolog programs that do not require equivariant unification, develop a test for identifying such programs, and prove the correctness of this test via a proof-theoretic argument.
We address the task of systematically designing efficient programs for parallel machines. Our approach starts with a sequential algorithm and proceeds by expressing it in terms of standard, pre-implemented parallel co...
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We address the task of systematically designing efficient programs for parallel machines. Our approach starts with a sequential algorithm and proceeds by expressing it in terms of standard, pre-implemented parallel components called skeletons. We demonstrate the skeleton-based design process using a tridiagonal system solver as our example application. We develop a cost-optimal parallel version of our application and implement it in message passing interface (MPI). the performance of our solution is demonstrated experimentally on a Cray T3E machine. (c) 2004 Elsevier B.V. All rights reserved.
Software agents are being produced in many different forms to carry out different tasks, with personal assistants designed to reduce the amount of effort it takes for the user to go about their daily tasks. Most perso...
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ISBN:
(纸本)9728865198
Software agents are being produced in many different forms to carry out different tasks, with personal assistants designed to reduce the amount of effort it takes for the user to go about their daily tasks. Most personal assistants work with user preferences when working out what actions to perform on behalf of their user. this paper describes a novel approach for modelling user behaviour in the application area of Diary Management withthe use of Inductive Logic programming.
We use a fully abstract denotational model to show that nested function calls and recursive definitions can be eliminated from SPCF (a typed functional language with simple non-local control operators) without losing ...
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ISBN:
(数字)9783540320142
ISBN:
(纸本)3540255931
We use a fully abstract denotational model to show that nested function calls and recursive definitions can be eliminated from SPCF (a typed functional language with simple non-local control operators) without losing expressiveness. We describe - via simple typing rules - an affine fragment of SPCF in which function nesting and recursion (other than iteration) are not permitted. We prove that this affine fragment is fully expressive in the sense that every term of SPCF is observationally equivalent to an affine term. Our proof is based on the observation of Longley - already used to prove universality and full abstraction results for models of SPCF that every type of SPCF is a retract of a first-order type. We describe retractions of this kind which are definable in the affine fragment. this allows us to transform an arbitrary SPCF term into an affine one by mapping it to a first-order term, obtaining an (affine) normal form, and then projecting back to the original type. In the case of finitary SPCF, the retraction is based on a simple induction, which yields bounds for the size of the resulting term. In the infinitary case, it is based on an analysis of the relationship between SPCF definable functions and strategies for computing them sequentially.
We show that a minimal dependent type theory based on Sigma-types and equality is degenerated in presence of computational classical logic. By computational classical logic is meant a classical logic derived from a co...
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ISBN:
(数字)9783540320142
ISBN:
(纸本)3540255931
We show that a minimal dependent type theory based on Sigma-types and equality is degenerated in presence of computational classical logic. By computational classical logic is meant a classical logic derived from a control operator equipped with reduction rules similar to the ones of Felleisen's C or Parigot's mu operators. As a consequence, formalisms such as Martin-Lof's type theory or the (Set-predicative variant of the) Calculus of Inductive Constructions are inconsistent in presence of computational classical logic. Besides, an analysis of the role of the eta-rule for control operators through a set-theoretic model of computational classical logic is given.
We give a new type inference algorithm for typing lambda-terms in Elementary Affine Logic (EAL), which is motivated by applications to complexity and optimal reduction. Following previous references on this topic, the...
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ISBN:
(数字)9783540320142
ISBN:
(纸本)3540255931
We give a new type inference algorithm for typing lambda-terms in Elementary Affine Logic (EAL), which is motivated by applications to complexity and optimal reduction. Following previous references on this topic, the variant of EAL type system we consider (denoted EAL*) is a variant where sharing is restricted to variables and without polymorphism. Our algorithm improves over the ones already known in that it offers a better complexity bound: if a simple type derivation for the term t is given our algorithm performs EAL* type inference in polynomial time in the size of the derivation.
Within one model, behavioural consistency of its constituents is often problematic. Within UML such horizontal behavioural consistency between the objects of a concrete model, is particularly needed in the context of ...
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ISBN:
(纸本)354025630X
Within one model, behavioural consistency of its constituents is often problematic. Within UML such horizontal behavioural consistency between the objects of a concrete model, is particularly needed in the context of dynamic patterns. Here, we investigate delegation, which is fundamental to patterns that separate the locality of receiving a request, and one or more localities actually handling it. We specify delegation by means of the coordination language Paradigm. In particular, we present some variants of delegation in the context of a broker pattern and clarify how the Paradigm notions are the basis for understanding a solution as well as for adapting it to deal with other dynamic features.
Reactive programming has been added to the traditional Linda programming style in order to deal withthe dynamic aspects of those applications in which it is important to observe modifications of the environment which...
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ISBN:
(纸本)354025630X
Reactive programming has been added to the traditional Linda programming style in order to deal withthe dynamic aspects of those applications in which it is important to observe modifications of the environment which occur quickly. Reactive programming is embedded in shared data spaces by defining the observable entities and the corresponding reactions that usually are processes possibly executing coordination primitives. Typical observable entities are the presence in the space of a datum (state-based) or the execution of a particular primitive (event-based). In this paper we consider different models of reaction execution adopted in the coordination literature so far, namely the prioritized model (used e.g. in MARS [3], TuCSoN [8] and LIME [9]) and the parallel execution model (considered e.g. in JavaSpaces [13], TSpaces [14] and WCL [11]). Prioritized reactions are usually implemented at server-side as during their execution no other coordination primitives can take place;parallel reactions, more suited when reactions are executed at client-side, are executed in parallel withthe other processes in the system (thus other coordination primitives can interleave withthe reactions). Using a process algebraic setting we perform a rigorous investigation of the relative advantages and disadvantages of these two models for reaction execution.
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