A multiple wire magnetostrictive delay line for improved signal and reduced reflections

The amplitude of the output signal per unit of cross sectional area of a magnetostrictive delay line decreases for increasing wire diameter due to the skin effect. For a fixed area a large output signal can be obtained by using a number of thin wires. An additional advantage is the reduced influence of inhomogeneities along the wires. Reflections in this multiple wire delay line can be reduced firstly by means of interference by fixing half of the number of wires to a mass and leaving the other half ends free, and/or secondly through spreading out the reflections by shifting the ends of the wires with respect to each other. A simple magneto-acoustic position measurement system using a multiple wire delay line and one single transmitting/receiving coil is demonstrated

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 callgraphs. Standard software metrics are applicable to these models. A Miranda front end for Prometrix, ¿, 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

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 testin

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

Validation in the Software Metric Development Process

In this paper the validation of software metrics will be examined. Two approaches will be combined: representational measurement theory and a validation network scheme. The development process of a software metric will be described, together with validities for the three phases of the metric development process. Representation axioms from measurement theory are used both for the formal and empirical validation. The differentiation of validities according to these phases unifies several validation approaches found in the software metric's literature

A Conceptual Formalization of Crosscutting in AOSD

We propose a formalization of crosscutting based on a conceptual framework for AOSD. Crosscutting is clearly distinguished from the related concepts scattering and tangling. The definitions of these concepts are formalized and visualized with matrices and matrix operations. This allows more precise reasoning about crosscutting

Change Impact Analysis based on Formalization of Trace Relations for Requirements

Evolving customer needs is one of the driving factors in software development. There is a need to analyze the impact of requirement changes in order to determine possible conflicts and design alternatives influenced by these changes. The analysis of the impact of requirement changes on related requirements can be based on requirements traceability. In this paper, we propose a requirements metamodel with well defined types of requirements relations. This metamodel represents the common concepts extracted from some prevalent requirements engineering approaches. The requirements relations in the metamodel are used to trace related requirements for change impact analysis. We formalize the relations. Based on this formalization, we define change impact rules for requirements. As a case study, we apply these rules to changes in the requirements specification for Course Management System

Manganese ferrite thin films Part I: Preparation and structure

The preparation of manganese ferrite thin films by the reactive evaporation of oxidic materials is reported. The process is not critical and provides homogeneous mirror-like films with spinel structure. An annealing procedure below 750 °C has a strong influence on the properties of the films. Special attention is paid to the partial oxygen pressure during the annealing process. For this purpose data are collected from the literature concerning the equilibrium conditions of the spinel structure for varying manganese-iron contents. The lattice constant of the spinel structure of the films is determined by electron diffraction

AOSD Ontology 1.0 - Public Ontology of Aspect-Orientation

This report presents a Common Foundation for Aspect-Oriented Software Development. A Common Foundation is required to enable effective communication and to enable integration of activities within the Network of Excellence. This Common Foundation is realized by developing an ontology, i.e. the shared meaning of terms and concepts in the domain of AOSD. In the first part of this report, we describe the definitions of an initial set of common AOSD terms. There is general agreement on these definitions. In the second part, we describe the Common Foundation task in detail

Crosscutting, what is and what is not? A Formal definition 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. Using linear algebra, we demonstrate that our definition generalizes other definitions of crosscutting as described by Masuhara & Kiczales [21] and Tonella and Ceccato [28]. The framework can be applied across several refinement levels assuring traceability of crosscutting concerns. Usability of the framework is illustrated by means of applying it to several areas such as change impact analysis, identification of crosscutting at early phases of software development and in the area of model driven software development