Testing refinements by refining tests

One of the potential benefits of formal methods is that they offer the possibility of reducing the costs of testing. A specification acts as both the benchmark against which any implementation is tested, and also as the means by which tests are generated. There has therefore been interest in developing test generation techniques from formal specifications, and a number of different methods have been derived for state based languages such as Z, B and VDM. However, in addition to deriving tests from a formal specification, we might wish to refine the specification further before its implementation. The purpose of this paper is to explore the relationship between testing and refinement. As our model for test generation we use a DNF partition analysis for operations written in Z, which produces a number of disjoint test cases for each operation. In this paper we discuss how the partition analysis of an operation alters upon refinement, and we develop techniques that allow us to refine abstract tests in order to generate test cases for a refinement. To do so we use (and extend existing) methods for calculating the weakest data refinement of a specification

Light-lift helicopter logging operations in the Italian Alps: a preliminary study based on GNSS and a video camera system

Terrain access is a critical factor influencing the feasibility of forest operations in steep mountainous terrain. Long extraction distances coupled with terrain obstacles can favor the use of helicopters in timber extraction in such areas. However, helicopter logging in the Italian Alps is not commonplace when compared to other Alpine regions, for example, in Switzerland and Austria. The use of light-lift helicopters has recently caught the attention of practitioners as an alternative to more traditional medium- to heavy-lift aircraft in the Alps. This article reports the findings of two preliminary case studies using light-lift helicopters for the extraction of high value timber and fire-damaged timber subsequently exposed to bark beetle disturbance. In order to provide a comprehensive analysis of the factors affecting helicopter logging productivity, the two case studies were separately analyzed using time-element analysis supported by on-board global navigation satellite system (GNSS) devices. Additio..

The specification and testing of conformance in ODP systems

Open Distributed Processing (ODP) is a joint standardisation activity of the ISO and ITU. A reference model has been defined which describes an architecture for building open distributed systems. This paper introduces the key aspects of the reference model of open distributed processing, including the ODP conformance framework. We discuss how specific formal techniques are used in the ODP viewpoints, along with the implications for conformance assessment using such techniques. Particular attention is given to the role of consistency in the conformance assessment process. Finally, we review the current work on an ODP conformance testing methodology. Keywords: Open Distributed Processing; Conformance; Formal Description Techniques. 1 THE OPEN DISTRIBUTED PROCESSING MODEL Open Distributed Processing (ODP) [29] is a joint standardisation activity of the ISO and ITU. A reference model has been defined which describes an architecture for building open distributed systems [36, 33]. Central..