K.G. van den Berg

Control-flow semantics of use cases in UML

The control-flow for five kinds of use cases is analysed: for common use cases, variant use cases, component use cases, specialised use cases and for ordered use cases. The control-flow semantics of use cases - and of the uses-relation, the extends-relation and the precedes-relation between use cases - is described in terms of flowgraphs. Sequence diagrams of use cases are refined to capture the control-flow adequately. Guidelines are given for use case descriptions to attain a well-defined flow of control.

Static analysis of functional programs

In this paper, the static analysis of programs in the functional programming language Miranda is described based on two graph models. A new control-flow graph model of Miranda definitions is presented, and a model with four classes of caligraphs. Standard software metrics are applicable to these models. A Miranda front end for Prometrixt, a tool for the automated analysis of flowgraphs and callgraphs, has been developed. This front end produces the flowgraph and callgraph representations of Miranda programs. Some features of the metric analyser are illustrated with an example program. The tool provides a promising access to standard metrics on functional programs.

Disentangling crosscutting in AOSD: formalization based on a crosscutting pattern

Crosscutting is usually described in terms of scattering and tangling. However, the distinction between these concepts is vague, which could lead to ambiguous statements. Sometimes, precise definitions are required, e.g., for the formal identification of crosscutting concerns. We propose a conceptual framework for formalizing these concepts based on a crosscutting pattern that shows the mapping between elements at two levels, e.g., concerns and representations of concerns. The definitions of the concepts are formalized in terms of linear algebra, and visualized with matrices and matrix operations. In this way, crosscutting can be clearly distinguished from scattering and tangling. The usability of dependency matrices is illustrated in the analysis of crosscutting across several refinement levels, which can be formalized through the cascading of the crosscutting pattern.

Programmers Performance on Structured versus Nonstructured Function Definitions

A control-flow model for functional programs is used in an experimental comparison of the performance of programmers on structured versus nonstructured Miranda function definitions. The performance is taken as a measure of the comprehensibility of functional programs. The experimental set-up is similar to the Scanlan study (1989). However, in the present study, a two-factor repeated measures design is used in the statistical analysis. The control-flow model appears to be useful in the shaping of the experiment. A significantly better performance has been found for structured function definitions on both dependent variables: the time needed to answer questions about the function definitions and the proportion correct answers. Moreover, for structured function definitions, a counter-intuitive result has been obtained: there are significantly fewer errors in larger definitions than in smaller ones.

A Generalised Approach to Software Structure Metrics

The aim of this paper is to generalise the Fenton-Whitty-Kaposi (FWK) approach to structure software metrics by considering arbitrary sets of decomposition operations for flowgraphs. In the FWK approach decomposition of flowgraphs is unique, but the number of associated metric functions is not finite and these functions are all independent. In general, the decomposition of flowgraphs is not unique, which leads to constraints on the associated metric functions. Here we derive these constraints explicitly for two special cases, where we consider only the two operations sequencing and nesting as decomposition operations. It is shown that the two resulting classes of structure metrics are contained in the class of recursive structure metrics of the FWK approach.

Validation of structure metrics: a case study

A framework for the validation of axiomatic structure metrics is presented. In a case study, the comprehensibility of type expressions in the functional programming language Miranda has been investigated. A structure metric for the comprehensibility of type expressions has been developed together with internal and external axioms. This structure metric has been validated experimentally. The calibrated metric function results in a good prediction of the comprehensibility. >

Axiomatic testing of structure metrics

Axiomatic testing of software metrics is described, based on axioms from representational measurement theory. In a case study, the axioms are given for the formal relational structure and the empirical relational structure. Two approaches to axiomatic testing are elaborated: deterministic testing and probabilistic testing. >Axiomatic testing of software metrics is described, based on axioms from representational measurement theory. In a case study, the axioms are given for the formal relational structure and the empirical relational structure. Two approaches to axiomatic testing are elaborated: deterministic testing and probabilistic testing.<<ETX>>

Musical equational programs: a functional approach

In this paper we solve musical equational programs by means of higher order functions. The initial solution is written in a functional programming language (Miranda1). It is shown how a solution in an imperative language (Pascal) can be obtained by elimination of the higher order functions.