70 research outputs found

    Self organising maps for visualising and modelling

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    The paper describes the motivation of SOMs (Self Organising Maps) and how they are generally more accessible due to the wider available modern, more powerful, cost-effective computers. Their advantages compared to Principal Components Analysis and Partial Least Squares are discussed. These allow application to non-linear data, are not so dependent on least squares solutions, normality of errors and less influenced by outliers. In addition there are a wide variety of intuitive methods for visualisation that allow full use of the map space. Modern problems in analytical chemistry include applications to cultural heritage studies, environmental, metabolomic and biological problems result in complex datasets. Methods for visualising maps are described including best matching units, hit histograms, unified distance matrices and component planes. Supervised SOMs for classification including multifactor data and variable selection are discussed as is their use in Quality Control. The paper is illustrated using four case studies, namely the Near Infrared of food, the thermal analysis of polymers, metabolomic analysis of saliva using NMR, and on-line HPLC for pharmaceutical process monitoring

    Adult Attention Deficit Hyperactivity Disorder and Violence in the Population of England: Does Comorbidity Matter?

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    It is unclear whether the association between Attention Deficit/Hyperactivity Disorder (ADHD) and violence is explained by ADHD symptoms or co-existing psychopathology. We investigated associations of ADHD and its symptom domains of hyperactivity and inattention, among individuals reporting violence in the UK population. Methods We report data from the Adult Psychiatric Morbidity Survey (2007), a representative sample of the household population of England. A randomly selected sample of 7,369 completed the Adult Self-Report Scale for ADHD and the self-reported violence module, including repetition, injury, minor violence, victims and location of incidents. All models were weighted to account for non-response and carefully adjusted for demography and clinical predictors of violence: antisocial personality, substance misuse and anxiety disorders. Results ADHD was moderately associated with violence after adjustments (OR 1.75, p = .01). Hyperactivity, but not inattention was associated with several indicators of violence in the domestic context (OR 1.16, p = .03). Mild and moderate ADHD symptoms were significantly associated with violence repetition, but not severe ADHD where the association was explained by co-existing disorders. Stratified analyses further indicated that most violence reports are associated with co-occurring psychopathology. Conclusions The direct effect of ADHD on violence is only moderate at the population level, driven by hyperactivity, and involving intimate partners and close persons. Because violence associated with severe ADHD is explained by co-existing psychopathology, interventions should primarily target co-existing disorders

    Technology-supported learning innovation in cultural contexts

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    Many reform initiatives adopt a reductionist, proceduralized approach to cultural change, assuming that deep changes can be realized by introducing new classroom activities, textbooks, and technological tools. This article elaborates a complex system perspective of learning culture: A learning culture as a complex system involves macro-level properties (e.g., epistemological beliefs, social values, power structures) and micro-level features (e.g., technology, classroom activities). Deep changes in macro-level properties cannot be reduced to any component. This complex system perspective is applied to examining technology-supported educational change in East Asia and analyzing how teachers sustain the knowledge building innovation in different contexts. Working with the macro-micro dynamics in a learning culture requires a principle-based approach to learning innovation that specifies macro-level changes using principle-based instead of procedure-based terms and engages teachers’ deep reflection and creative engagement at both the macro- and the micro-level
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