From formal models to formally based methods

Abstract

We address the problem of increasing the impact of formal methods in the practice of industrial computer applications. We summarize the reasons why formal methods so far did not gain widespread use within the industrial environment despite several promising experiences. We suggest an evolutionary rather than revolutionary attitude in the introduction of formal methods in the practice of industrial applications and we report on our long-standing experience which involves an academic institution, Politecnico di Milano, two main industrial partners, ENEL and CISE, and occasionally a few other industries. Our approach aims at augmenting an existing and fairly deeply rooted informal industrial methodology with our original formalism, the logic specification language TRIO. On the basis of the experiences we gained we argue that our incremental attitude towards the introduction of formal methods within the industry could be effective largely independently from the chosen formalism.

From Interaction Overview Diagrams to Temporal Logic

“…TRIO [7] is a general-purpose formal specification language suitable for describing complex real-time systems, including distributed ones. TRIO is a first-order linear temporal logic that supports a metric on time.…”

“…In the case of SD downloadSMS of Figure 2, the instances of formulae (7)(8)(9) are given by (12)(13)(14). In addition, formulae (10-11) define the necessary conditions to start diagram downloadSMS : either diagram delegateSMS ends, or diagram downloadSMS ends and condition moredata holds.…”

Integrating Discrete- and Continuous-Time Metric Temporal Logics Through Sampling

“…Let us start by presenting our reference metric temporal logic, namely TRIO [10,15,5]. More precisely, this section introduces a fragment of full TRIO that we shall call ¡ TRIO 2 ; it is a syntactic and expressive subset of the former, robust with respect to our notion of sampling invariance (as it will be defined in the following Section 3).…”

“…Whereas TRIO is based on a single modal operator named Dist [5], ¡ TRIO adopts the bounded Until and Since as primitive operators, because this permits a simpler statement of the sampling invariance results. More precisely, let Ξ be a set of time-dependent conditions.…”

“…Some temporal logic languages have semantics for both a continuous-time model and a discrete-time one: each formula of the language can be interpreted in one of the two classes of models. TRIO is an example of these logics [5], the one we are considering in this paper; MTL [14] is another well-known instance. 1 The discrete-time semantics and the continuous-time one, however, are unrelated in general, in that the same formula unpredictably changes its models when passing from one semantics to another.…”