Fair Pi

International audienceIn this paper, we define fair computations in the pi-calculus. We follow Costa and Stirling's approach for CCS-like languages but exploit a more natural labeling method of process actions to filter out unfair process executions. The new labeling allows us to prove all the significant properties of the original one, such as unicity, persistence and disappearance of labels. It also turns out that the labeled pi-calculus is a conservative extension of the standard one. We contrast the existing fair testing with those that naturally arise by imposing weak and strong fairness as defined by Costa and Stirling. This comparison provides the expressiveness of the various fair testing-based semantics and emphasizes the discriminating power of the one already proposed in the literature

Fair Π

AbstractIn this paper, we define fair computations in the π-calculus [Milner, R., Parrow, J. & Walker, D., A Calculus of Mobile Processes, Part I and II, Information and Computation 100 (1992) 1–78]. We follow Costa and Stirling's approach for CCS-like languages [Costa, G. & Stirling, C., A Fair Calculus of Communicating Systems, Acta Informatica 21 (1984) 417–441, Costa, G. & Stirling, C., Weak and Strong Fairness in CCS, Information and Computation 73 (1987) 207–244] but exploit a more natural labeling method of process actions to filter out unfair process executions. The new labeling allows us to prove all the significant properties of the original one, such as unicity, persistence and disappearance of labels. It also turns out that the labeled π-calculus is a conservative extension of the standard one. We contrast the existing fair testing [Brinksma, E., Rensink, A. & Vogler, W., Fair Testing, Proc. of CONCUR'95, LNCS, 962 (1995) 313–327, Natarajan, V. & Cleaveland, R., Divergence and Fair Testing, Proc. of ICALP '95, LNCS, 944 (1995) 648–659] with those that naturally arise by imposing weak and strong fairness as defined by Costa and Stirling. This comparison provides the expressiveness of the various fair testing-based semantics and emphasizes the discriminating power of the one already proposed in the literature

Explicit fairness in testing semantics

In this paper we investigate fair computations in the pi-calculus. Following Costa and Stirling's approach for CCS-like languages, we consider a method to label process actions in order to filter out unfair computations. We contrast the existing fair-testing notion with those that naturally arise by imposing weak and strong fairness. This comparison provides insight about the expressiveness of the various `fair' testing semantics and about their discriminating power.Comment: 27 pages, 1 figure, appeared in LMC

Explicit Fairness in Testing Semantics

International audienceIn this paper we investigate fair computations in the $\pi$-calculus \cite{MPW92}. Following Costa and Stirling's approach for CCS-like languages \cite{CS84,CS87}, we consider a method to label process actions in order to filter out unfair computations. We contrast the existing fair-testing notion \cite{RV07,NC95} with those that naturally arise by imposing weak and strong fairness. This comparison provides insight about the expressiveness of the various `fair' testing semantics and about their discriminating power

Linearity, Persistence and Testing Semantics in the Asynchronous Pi-Calculus

International audienceIn [CSVV06] the authors studied the expressiveness of persistence in the asynchronous pi calculus (Api) wrt weak barbed congruence. The study is incomplete because it ignores the issue of divergence. In this paper we present an expressiveness study of persistence in the asynchronous pi-calculus (Api) wrt DeNicola and Hennesy's testing scenario which is sensitive to divergence. We consider Api and theree sub-languages of it, each capturing one source of persistence: the persistent-input calculus (PIApi), the persistent-output calculus (POApi) and persistent calculus (PApi). In [CSVV06] the authors showed encodings from Api into semipersistent calculi are correct wrt weak barbed congruence. In this paper we prove that, under some general conditions, there cannot be an encoding from Api into a (semi)-persistent calculus preserving the must testing semantics. [CSVV06 ] C. Palamidessi, V. Saraswat, F. Valencia and B. Victor. On the Expressiveness of Linearity vs Persistence in the Asynchronous Pi Calculus. LICS 2006:59-68,2006

Linearity, Persistence and Testing Semantics in the Asynchronous Pi-Calculus

International audienceIn [CSVV06] the authors studied the expressiveness of persistence in the asynchronous pi calculus (Api) wrt weak barbed congruence. The study is incomplete because it ignores the issue of divergence. In this paper we present an expressiveness study of persistence in the asynchronous pi-calculus (Api) wrt DeNicola and Hennesy's testing scenario which is sensitive to divergence. We consider Api and theree sub-languages of it, each capturing one source of persistence: the persistent-input calculus (PIApi), the persistent-output calculus (POApi) and persistent calculus (PApi). In [CSVV06] the authors showed encodings from Api into semipersistent calculi are correct wrt weak barbed congruence. In this paper we prove that, under some general conditions, there cannot be an encoding from Api into a (semi)-persistent calculus preserving the must testing semantics. [CSVV06 ] C. Palamidessi, V. Saraswat, F. Valencia and B. Victor. On the Expressiveness of Linearity vs Persistence in the Asynchronous Pi Calculus. LICS 2006:59-68,2006

A Catalogue of Inter-Parameter Dependencies in RESTful Web APIs

Web services often impose dependency constraints that re strict the way in which two or more input parameters can be combined to form valid calls to the service. Unfortunately, current specification languages for web services like the OpenAPI Specification provide no support for the formal description of such dependencies, which makes it hardly possible to automatically discover and interact with services without human intervention. Researchers and practitioners are openly requesting support for modelling and validating dependencies among in put parameters in web APIs, but this is not possible unless we share a deep understanding of how dependencies emerge in practice—the aim of this work. In this paper, we present a thorough study on the presence of dependency constraints among input parameters in web APIs in in dustry. The study is based on a review of more than 2.5K operations from 40 real-world RESTful APIs from multiple application domains. Overall, our findings show that input dependencies are the norm, rather than the exception, with 85% of the reviewed APIs having some kind of dependency among their input parameters. As the main outcome of our study, we present a catalogue of seven types of dependencies consistently found in RESTful web APIsMinisterio de Economía y Competitividad BELI (TIN2015-70560-R)Ministerio de Ciencia, Innovación y Universidades Horatio RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU17/0407

Symbolic verification of event–condition–action rules in intelligent environments

In this paper we show how state-of-the art SMT-based techniques for software verification can be employed in the verification of event–condition–action rules in intelligent environments. Moreover, we exploit the specific features of intelligent environments to optimise the verification process. We compare our approach with previous work in a detailed evaluation section, showing how it improves both performance and expressivity of the language for event–condition–action rules

Multiscale Bone Remodelling with Spatial P Systems

Many biological phenomena are inherently multiscale, i.e. they are characterized by interactions involving different spatial and temporal scales simultaneously. Though several approaches have been proposed to provide "multilayer" models, only Complex Automata, derived from Cellular Automata, naturally embed spatial information and realize multiscaling with well-established inter-scale integration schemas. Spatial P systems, a variant of P systems in which a more geometric concept of space has been added, have several characteristics in common with Cellular Automata. We propose such a formalism as a basis to rephrase the Complex Automata multiscaling approach and, in this perspective, provide a 2-scale Spatial P system describing bone remodelling. The proposed model not only results to be highly faithful and expressive in a multiscale scenario, but also highlights the need of a deep and formal expressiveness study involving Complex Automata, Spatial P systems and other promising multiscale approaches, such as our shape-based one already resulted to be highly faithful.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005