46 research outputs found
Specification of tools for message sequence charts
. The recent formalization of the semantics of Message Sequence Charts enables the derivation of tools for MSCs directly from this formal definition. We use the Asf+Sdf Meta-environment to make a straightforward implementation of tools for transformation, simulation and requirements testing. In this paper we present the complete specification of the tools. 1 Introduction Message Sequence Charts (MSCs) are a graphical method for the description of the interaction between system components [IT94]. Due to the recent formalization [MR94a, MR94b, IT95] of the semantics of Message Sequence Charts, we can consider MSC as a formal description technique. Currently, this formalization has already influenced the development of the language (in particular with respect to composition of MSCs, for which algebraic operators are considered) and it is expected to also influence the use of MSCs. Formalization will also have impact on the work of tool builders. The behavior of tools can be validated aga..
Distributional inference
The making of statistical inferences in distributional form is conceptionally complicated because the epistemic 'probabilities' assigned are mixtures of fact and fiction. In this respect they are essentially different from 'physical' or 'frequency-theoretic' probabilities. The distributional form is so attractive and useful, however, that it should be pursued. Our approach is In line with Walds theory of statistical decision functions and with Lehmann's books about hypothesis testing and point estimation: loss functions are defined, risk functions are studied, unbiasedness and equivariance restrictions are made, etc. A central theme is that the loss function should be 'proper'. This fundamental concept has been explored by meteorologists, psychometrists, Bayesian statisticians, and others. The paper should be regarded as an attempt to reconcile various schools of statisticians. By accepting what we regard 88 good and useful in the various approaches we are trying to develop a nondogmatic approach
Industrial applications of ASF+SDF
In recent years, a number of Dutch companies have used the algebraic specification formalism ASF+SDF. Bank MeesPierson has specified a language for describing interest rate products, their translation into COBOL, and their generation from interactive questionnaires. A consultancy company has specified a language to represent the company's object-oriented models, and the compilation of this language into Access. Bank ABN-AMRO has started investigating the use of algebraic specifications for renovating legacy COBOL systems. We discuss the implications of such projects for teaching algebraic specifications and software engineering, and the role students have been playing in these projects
A bi-dimensional taxonomy of social responsivity in middle childhood: prosociality and reactive aggression predict externalizing behavior over time
Developing social skills is essential to succeed in social relations. Two important social constructs in middle childhood, prosocial behavior and reactive aggression, are often regarded as separate behaviors with opposing developmental outcomes. However, there is increasing evidence for the co-occurrence of prosociality and aggression, as both might indicate responsivity to the social environment. Here, we tested whether a bi-dimensional taxonomy of prosociality and reactive aggression could predict internalizing and externalizing problems over time. We re-analyzed data of two well-validated experimental tasks for prosociality (the Prosocial Cyberball Game) and reactive aggression (the Social Network Aggression Task) in a developmental population sample (n = 496, 7-9 years old). Results revealed no associations between prosociality and reactive aggression, confirming the independence of those constructs. Interestingly, although prosociality and reactive aggression independently did not predict problem behavior, the interaction of both was negatively predictive of changes in externalizing problems over time. Specifically, only children who scored low on both prosociality and reactive aggression showed an increase in externalizing problems 1 year later, whereas levels of externalizing problems did not change for children who scored high on both types of behavior. Thus, our results suggest that at an individual level, reactive aggression in middle childhood might not always be maladaptive when combined with prosocial behavior, thereby confirming the importance of studying social competence across multiple dimensions.Pathways through Adolescenc
Genetic and environmental influences on structure of the social brain in childhood
Prosocial behavior and empathy are important aspects of developing social relations in childhood. Prior studies showed protracted structural development of social brain regions associated with prosocial behavior. However, it remains unknown how structure of the social brain is influenced by genetic or environmental factors, and whether overlapping heritability factors explain covariance in structure of the social brain and behavior. The current study examined this hypothesis in a twin sample (aged 7-9-year; N = 512). Bilateral measures of surface area and cortical thickness of the medial prefrontal cortex (mPFC), temporo-parietal junction (TPJ), posterior superior temporal sulcus (pSTS), and precuneus were analyzed. Results showed genetic contributions to surface area and cortical thickness for all brain regions. We found additional shared environmental influences for TPJ, suggesting that this region might be relatively more sensitive to social experiences. Genetic factors also influenced parent-reported prosocial behavior (A = 45%) and empathy (A = 59%). We provided initial evidence that the precuneus shares genetically determined variance with empathy, suggesting a possible small genetic overlap (9%) in brain structure and empathy. These findings show that structure of the social brain and empathy are driven by a combination of genetic and environmental factors, with some factors overlapping for brain structure and behavior.Neuro Imaging Researc
Genetic and environmental influences on structure of the social brain in childhood
Prosocial behavior and empathy are important aspects of developing social relations in childhood. Prior studies showed protracted structural development of social brain regions associated with prosocial behavior. However, it remains unknown how structure of the social brain is influenced by genetic or environmental factors, and whether overlapping heritability factors explain covariance in structure of the social brain and behavior. The current study examined this hypothesis in a twin sample (aged 7–9-year; N = 512). Bilateral measures of surface area and cortical thickness of the medial prefrontal cortex (mPFC), temporo-parietal junction (TPJ), posterior superior temporal sulcus (pSTS), and precuneus were analyzed. Results showed genetic contributions to surface area and cortical thickness for all brain regions. We f