Jesús Aranda

Formal Methods for Components and Objects

Testing.- Model-Based Testing of Environmental Conformance of Components.- Exhaustive Testing of Exception Handlers with Enforcer.- Model-Based Test Selection for Infinite-State Reactive Systems.- Program Verification.- Verifying Object-Oriented Programs with KeY: A Tutorial.- Rebeca: Theory, Applications, and Tools.- Learning Meets Verification.- Trust and Security.- JACK - A Tool for Validation of Security and Behaviour of Java Applications.- Towards a Formal Framework for Computational Trust.- Models of Computation.- On Recursion, Replication and Scope Mechanisms in Process Calculi.- Bounded Session Types for Object Oriented Languages.- Distributed Programming.- Reflecting on Aspect-Oriented Programming, Metaprogramming, and Adaptive Distributed Monitoring.- Links: Web Programming Without Tiers.

An Overview of FORCES: An INRIA Project on Declarative Formalisms for Emergent Systems

The FORCES project aims at providing robust and declarative formalisms for analyzing systems in the emerging areas of Security Protocols, Biological Systems and Multimedia Semantic Interaction . This short paper describes FORCESs motivations, results and future research directions.

CCS with replication in the Chomsky hierarchy: the expressive power of divergence

A remarkable result in [4] shows that in spite of its being less expressive than CCS w.r.t. weak bisimilarity, CCS! (a CCS variant where infinite behavior is specified by using replication rather than recursion) is Turing powerful. This is done by encoding Random Access Machines (RAM) in CCS!. The encoding is said to be non-faithful because it may move from a state which can lead to termination into a divergent one which do not correspond to any configuration of the encoded RAM. I.e., the encoding is not termination preserving. In this paper we study the existence of faithful encodings into CCS! of models of computability strictly less expressive than Turing Machines. Namely, grammars of Types 1 (Context Sensitive Languages), 2 (Context Free Languages) and 3 (Regular Languages) in the Chomsky Hierarchy. We provide faithful encodings of Type 3 grammars. We show that it is impossible to provide a faithful encoding of Type 2 grammars and that termination-preserving CCS! processes can generate languages which are not Type 2. We finally show that the languages generated by termination-preserving CCS! processes are Type 1.

On recursion, replication and scope mechanisms in process calculi

In this paper we shall survey and discuss in detail the work on the relative expressiveness of recursion and replication in various process calculi. Namely, CCS, the π-calculus, the Ambient calculus, Concurrent Constraint Programming and calculi for Cryptographic Protocols. We shall give evidence that the ability of expressing recursive behaviour via replication often depends on the scoping mechanisms of the given calculus which compensate for the restriction of replication.

Making Decisions on the Student Quota Problem: A Case Study Using a MIP Model

The aim of this paper is to present a model to support the decision making process on the Student Quota Problem (i.e., the maximum number of students that could be admitted in a university program). The number of students attended by universities is a key factor of national and international policies. The Organization for Economic Co-operation and Development (OECD) and Colombian official entities use this indicator to define goals of the educational level of young population. However, while the expectations of increasing the number of attended students are high, there are limits of growth based on resource limitations.

Towards Formal Interaction-Based Models of Grid Computing Infrastructures

Grid computing (GC) systems are large-scale virtual machines, built upon a massive pool of resources (processing time, storage, software) that often span multiple distributed domains. Concurrent users interact with the grid by adding new tasks; the grid is expected to assign resources to tasks in a fair, trustworthy way. These distinctive features of GC systems make their specification and verification a challenging issue. Although prior works have proposed formal approaches to the specification of GC systems, a precise account of the interaction model which underlies resource sharing has not been yet proposed. In this paper, we describe ongoing work aimed at filling in this gap. Our approach relies on (higher-order) process calculi: these core languages for concurrency offer a compositional framework in which GC systems can be precisely described and potentially reasoned about.

Granular: An access control model, and Confia: Its software tool

We present a new access control method called Granular. Granular extends traditional access control methods in order to manage XML-like documents by means of a rules set that allows easy administration of the system describing the accessed content using a suitable set of rights. One of the main novelties is the definition of closed and open authorizations, which provides a more precise way of controlling document access. It allows for an early control of possible conflicts between different kinds of accesses. Formal definitions of Granular actions and rules are presented in this paper, and the implementation of Granular is discussed.