Traceability-based change management in operational mappings

This paper describes an approach for the analysis of changes in model transformations in the Model Driven Architecture (MDA). Models should be amenable to changes in user requirements and technological platforms. Impact analysis of changes can be based on traceability of model elements. We propose a model for generating trace links between model elements and study scenarios for changes in source models and how to identify the impacted elements in the target model

Role of product characteristics for the adoption of fruit and fruit product innovations

The aim of this study was the identification of those product characteristics that are important for the adoption of fruit and fruit product innovations by consumers. Sixteen focus group discussions were held in four European countries (Greece, The Netherlands, Poland, and Spain). Different aspects of six innovative fruit products were discussed, revealing those characteristics that were important for the adoption of each of them. It was observed that the participants did not perceive fruit innovations as a homogenous group, but assigned them to different groups, which led to a number of categories of fruit innovation. Three categories concerned the level of preparation of fruit. These were fresh, prepared, and processed fruit product innovations. Another two categories, radical and evolutionary innovations, related to the level of novelty of the fruit innovation. Characteristics important for the adoption of each of these categories are given.The results will be used for further, more quantitative, research

Factors contributing to the negation of therapeutic services by emerging adults at a South African university

From a practice point of view it seems as if there are certain factors that might contribute to the fact that emerging adults tend to negate therapeutic help and services. It also seems to be specifically true with regard to emerging adults at university. Help negation seems to occur albeit the fact that therapeutic intervention is seen as an effective tool in managing distress. The aim of the study therefore was to explore which factors contribute to help negation behaviour in emerging adults at a specific university in South Africa.A qualitative case study design was employed where participants who complied with the inclusion criteria set out for the study, were selected by means of non-probability target and snowball sampling. Fifteen students residing in campus residences respectively participated in one of three focus group discussions. Creswell’s spiral of data analysis was used to analyse the transcribed data.The data crystallised into four themes, which contribute to help negation behaviour in emerging adults. Emerging adults have a fear of being judged, stigmatised, recognised, of not being treated confidentially and a fear of being vulnerable and hurt. They prefer to seek help and support from their family and peers and to put their trust in God and their religion; they have internalised beliefs about themselves and therapy and a need for independence; student interns work at the therapeutic centres on campus which specifically contributes to help negation for emerging adults at the university. It is crucial that the professionals revisit their strategies and approaches in order to overcome negation of formal help and create a more understandable, approachable and effective therapeutic service to emerging adults, especially at university therapeutic centres

High orders of Weyl series for the heat content

This article concerns the Weyl series of spectral functions associated with the Dirichlet Laplacian in a $d$-dimensional domain with a smooth boundary. In the case of the heat kernel, Berry and Howls predicted the asymptotic form of the Weyl series characterized by a set of parameters. Here, we concentrate on another spectral function, the (normalized) heat content. We show on several exactly solvable examples that, for even $d$, the same asymptotic formula is valid with different values of the parameters. The considered domains are $d$-dimensional balls and two limiting cases of the elliptic domain with eccentricity $\epsilon$: A slightly deformed disk ($\epsilon\to 0$) and an extremely prolonged ellipse ($\epsilon\to 1$). These cases include 2D domains with circular symmetry and those with only one shortest periodic orbit for the classical billiard. We analyse also the heat content for the balls in odd dimensions $d$ for which the asymptotic form of the Weyl series changes significantly.Comment: 20 pages, 1 figur

On the minimization of Dirichlet eigenvalues of the Laplace operator

We study the variational problem \inf \{\lambda_k(\Omega): \Omega\ \textup{open in}\ \R^m,\ |\Omega| < \infty, \ \h(\partial \Omega) \le 1 \}, where $\lambda_k(\Omega)$ is the $k$'th eigenvalue of the Dirichlet Laplacian acting in $L^2(\Omega)$, \h(\partial \Omega) is the $(m-1)$- dimensional Hausdorff measure of the boundary of $\Omega$, and $|\Omega|$ is the Lebesgue measure of $\Omega$. If $m=2$, and $k=2,3, \cdots$, then there exists a convex minimiser $\Omega_{2,k}$. If $m \ge 2$, and if $\Omega_{m,k}$ is a minimiser, then $\Omega_{m,k}^*:= \textup{int}(\overline{\Omega_{m,k}})$ is also a minimiser, and $\R^m\setminus \Omega_{m,k}^*$ is connected. Upper bounds are obtained for the number of components of $\Omega_{m,k}$. It is shown that if $m\ge 3$, and $k\le m+1$ then $\Omega_{m,k}$ has at most $4$ components. Furthermore $\Omega_{m,k}$ is connected in the following cases : (i) $m\ge 2, k=2,$ (ii) $m=3,4,5,$ and $k=3,4,$ (iii) $m=4,5,$ and $k=5,$ (iv) $m=5$ and $k=6$. Finally, upper bounds on the number of components are obtained for minimisers for other constraints such as the Lebesgue measure and the torsional rigidity.Comment: 16 page

Survival probability (heat content) and the lowest eigenvalue of Dirichlet Laplacian

We study the survival probability of a particle diffusing in a two-dimensional domain, bounded by a smooth absorbing boundary. The short-time expansion of this quantity depends on the geometric characteristics of the boundary, whilst its long-time asymptotics is governed by the lowest eigenvalue of the Dirichlet Laplacian defined on the domain. We present a simple algorithm for calculation of the short-time expansion for an arbitrary "star-shaped" domain. The coefficients are expressed in terms of powers of boundary curvature, integrated around the circumference of the domain. Based on this expansion, we look for a Pad\'e interpolation between the short-time and the long-time behavior of the survival probability, i.e. between geometric characteristics of the boundary and the lowest eigenvalue of the Dirichlet Laplacian.Comment: Accepted in IJMP

Consumenten en de risico's en baten van voedselproducten

De centrale vraagstelling van dit rapport is hoe consumenten in hun percepties en gedrag afwegingen maken tussen negatieve en positieve gezondheidseffecten van voedingsmiddelen. Het rapport geeft een overzicht van de studies die verricht zijn op het gebied van risico- en batenafwegingen van consumenten, waarbij er een opsplitsing is gemaakt tussen risico's en baten, en tussen percepties (en attitudes) en gedrag. Samenvattend is de aanbeveling van het rapport om in toekomstig (kennisbasis)onderzoek naar risk-benefit afwegingen door consumenten groeps- en domeinspecifiek te werk te gaan

Variance Decomposition Using an IRT Measurement Model

Large scale research projects in behaviour genetics and genetic epidemiology are often based on questionnaire or interview data. Typically, a number of items is presented to a number of subjects, the subjects’ sum scores on the items are computed, and the variance of sum scores is decomposed into a number of variance components. This paper discusses several disadvantages of the approach of analysing sum scores, such as the attenuation of correlations amongst sum scores due to their unreliability. It is shown that the framework of Item Response Theory (IRT) offers a solution to most of these problems. We argue that an IRT approach in combination with Markov chain Monte Carlo (MCMC) estimation provides a flexible and efficient framework for modelling behavioural phenotypes. Next, we use data simulation to illustrate the potentially huge bias in estimating variance components on the basis of sum scores. We then apply the IRT approach with an analysis of attention problems in young adult twins where the variance decomposition model is extended with an IRT measurement model. We show that when estimating an IRT measurement model and a variance decomposition model simultaneously, the estimate for the heritability of attention problems increases from 40% (based on sum scores) to 73%

Environmental psychology:History, scope and methods

This book aims to give an introduction in environmental psychology. We defi ne environmental psychology as the discipline that studies the interplay between individuals and their built and natural environment. This means that environmental psychology examines the infl uence of the environment on human experiences, behaviour and well - being, as well as the infl uence of individuals on the environment, that is, factors infl uencing environmental behaviour, and ways to encourage pro - environmental behaviour. This book will give an overview of theories and research on each of these topics. In this introductory chapter we fi rst give a brief overview of the history of the fi eld of environmental psychology, followed by a discussion of characteristics of the fi eld and a description of the main methods used in research. The chapter ends with an outline and rationale of the book

Environmental psychology:History, scope and methods

This book aims to give an introduction in environmental psychology. We defi ne environmental psychology as the discipline that studies the interplay between individuals and their built and natural environment. This means that environmental psychology examines the infl uence of the environment on human experiences, behaviour and well - being, as well as the infl uence of individuals on the environment, that is, factors infl uencing environmental behaviour, and ways to encourage pro - environmental behaviour. This book will give an overview of theories and research on each of these topics. In this introductory chapter we fi rst give a brief overview of the history of the fi eld of environmental psychology, followed by a discussion of characteristics of the fi eld and a description of the main methods used in research. The chapter ends with an outline and rationale of the book