Resumo em Inglês:

We consider the inference problem for finite transducers using different kinds of samples (positive and negative samples, positive samples only, and structural samples). Given pairs of input and output words, our task is to infer the finite transducer consistent with the given pairs. We show that this problem can be solved in certain special cases by using known results on the inference problem for linear languages.

Resumo em Inglês:

We describe a simple representation for the modules of a graph G. We show that the modules of G are in one-to-one correspondence with the ideals of certain posets. These posets are characterized and shown to be layered posets, that is, transitive closures of bipartite tournaments. Additionaly, we describe applications of the representation. Employing the above correspondence, we present methods for solving the following problems: (i) generate all modules of G, (ii) count the number of modules of G, (iii) find a maximal module satisfying some hereditary property of G and (iv) find a connected non-trivial module of G.

Resumo em Inglês:

A formal specification can describe software models which are difficult to program. Transformational methods based on fold/unfold strategies have been proposed to palliate this problem. The objective of applying transformations is to filter out a new version of the specification where recursion may be introduced by a folding step. Among many problems, the "eureka" about when and how to define a new predicate is difficult to find automatically. We propose a new version of the folding rule which decides automatically how to introduce new predicates in a specification. Our method is based on finding similarities between formulas represented as parsing trees and it constitutes an assistance to the complex problem of deriving recursive specifications from non recursive ones.

Resumo em Inglês:

This article describes a compiler generator, called Mímico, that outputs code based on the use of monadic combinators. Mímico can parse infinite look-ahead and left-recursive context free grammars and defines a scheme for handling the precedence and associativity of binary infix operators, and monadic code in semantic rules. Mímico provides an easy way of specifying the syntax and semantics of languages, and generates readable output in the form of Haskell programs. The article presents Mímico's general principles, its formal syntax and semantics, its limitations and illustrative examples of its behaviour.

Resumo em Inglês:

This paper presents major quality of service problems in IEEE 802.11 networks. It analyzes unfairness in bandwidth sharing and TCP instability in MAC 802.11. Moreover, differentiation techniques for providing medium access priority are evaluated. Simulation results show that the ad hoc routing protocol has a great influence on unfairness and on the TCP throughput instability due to succeeding routing failures originated by the MAC sublayer. Differentiation mechanism results show that DIFS-based schemes can provide a fine-grained throughput differentiation compared to backoff-based ones. Nevertheless, backoff-based schemes are more effective in providing latency differentiation, which is important for real-time traffic.