“UML–ising” Formal Techniques

Abstract

Abstract. This invited paper presents a number of correlated specifications of example railway system problems. They use a variety of partially or fully integrated formal specification. The paper thus represents a mere repository of what we consider interesting case studies.The existence of the Unified Modeling Language [10,67,36,20] has caused, for one reason or another, the research community to try formalise one or another facet of UML. In this paper we report on another way to achieve what UML attempts to achieve: Broadness of application, convenience of notation, and multiplicity of views. Whether these different UML views are unified, integrated, correlated or merely co-located is for others to dispute. We also seek to support multiple views, but are also in no doubt that there must be sound, well defined relations between such views.We thus report on ways and means of integrating formal techniques such as RAISE (RSL) [18,45,46], and TRSL with Duration Calculus [79,30]. In this way one achieves a firm foundation for combined uses of these formal development techniques, one that can be believably deployed for as wide a spectrum, or even a wider spectrum of software (and hardware) development, as, respectively than UML.1 The Problem The IssuesWhen we describe, in informal, yet reasonably precise natural (or at least domain specific professional) language the entities, the functions, the events and behaviours of an application domain, then we encounter, perhaps, little, if any problem. Our use of natural language is very flexible. Without hardly noticing it, we slip from one mode of description to another mode. (What these modes are will be apparent in the next paragraph.)When, now, on the basis of the informal narrative, we wish to formalise this description, then we might very well encounter serious problems. We refer here to the current inability of any one formal specification language to cater for all kinds of modes: Functional, imperative (ie., with states being changed by assignments to variables), logical, temporal, and concurrency modes, the latter with events and behaviours. In particular we often slip, in natural language, from describing such qualitative aspects of timing as concurrent behaviours and their synchronisation and communication, to such quantitative aspects of timing as absolute and relative time: "12:05 am" to "after 5 minutes and 30 seconds" -without hardly noticing it.

A cloverleaf of software engineering

“…It is somewhat problematic to try make UML professionally acceptable as one would then try to capture an erratically (read: politically) moving target. We prefer, rather, to be inspired by the unquestionably good ideas of importing diagrammatic notations into UML by, instead, integrating them into clusters of formal techniques [6].…”

Exploiting multiformalism models for testing and performance evaluation in SIMTHESys

“…Z variants and process algebras combination are given in [10], [17], [19] and extensions to include other formalisms are presented in [14], [20]. Some more examples of combinations are provided in [4], that also suggests many other useful references on the topic. In the example used in this paper we will couple performance oriented formal methods with a verification automata-like language, that is newly designed though is inspired to [2], [1], and a reliability formalism based on Repairable Fault Trees [21].…”

“…In this paper we will implement a repairable variant of FT, in which a BE is a repairable event, to enable the TE of a FT to dynamically evaluate the overall condition of a system. The elements of the FT formalism are presented in table 3 4 . A BE is described by a BasicEvent element.…”

“…The complete FDL description of FCQN is available at www.dem.unina2.it/simthesys 4. The complete FDL description of FT is available at www.dem.unina2.it/simthesys 5.…”