823 research outputs found

    Structural properties of a calcium aluminosilicate glass from molecular-dynamics simulations: A finite size effects study

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    We study a calcium aluminosilicate glass of composition (SiO2_2)0.67_{0.67}-(Al2_2O3_3)0.12_{0.12}-(CaO)0.21_{0.21} by means of molecular-dynamics (MD) simulations, using a potential made of two-body and three-body interactions. In order to prepare small samples that can subsequently be studied by first-principles, the finite size effects on the liquid dynamics and on the glass structural properties are investigated. We find that finite size effects affect the Si-O-Si and Si-O-Al angular distributions, the first peaks of the Si-O, Al-O and Ca-O pair correlation functions, the Ca coordination and the oxygen atoms environment in the smallest system (100 atoms). We give evidence that these finite size effects can be directly attributed to the use of three-body interactions.Comment: 36 pages, 14 figures. Journal of Chem. Phys., in pres

    Der Aufbau sozialer Beziehungen mit einem Roboter. Eine Beobachtungsstudie im Feld

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    Roboter nehmen in letzter Zeit vermehrt Einzug in verschiedene Lebensbereiche. Es werden nicht nur Haushaltsroboter, die staubsaugen, oder Roboter, die vorrangig Entertainment-Zwecken dienen, angeboten, sondern in einigen Altenheimen werden Roboter bereits eingesetzt, um Senioren Gesellschaft zu leisten. Vor diesem Hintergrund untersucht die Studie als Teil des EU Forschungsprojektes SERA (Social Engagement with Robots and Agents), ob und inwiefern soziale Beziehungen zu Robotern aufgebaut werden. In einer Beobachtungsstudie und einem anschließenden qualitativen Interview wurden drei weibliche Teilnehmer (zwischen 50 und 65 Jahren) über eine Woche in der Interaktion mit einem Nabaztag beobachtet. Dieser Roboter in Hasenform wurde für die Studie so programmiert, dass er mit den Untersuchungsteilnehmerinnen Dialoge rund um das Thema Gesundheit und Fitness führen konnte. Der Roboter nutzte Sprachoutput, der Input von Seiten der Teilnehmerinnen wurde über Ja/Nein Knöpfe vorgenommen. Mit einer Webcam wurden 66 Interaktionen aufgezeichnet. Die kategorienbasierte Auswertung der Transkripte zeigte z.B., dass der Nabaztag häufig natürlich-sprachlich adressiert wurde und ihm beispielsweise alltägliches Verhalten erklärt wurde, obwohl die Probandinnen wussten, dass der Roboter sie nicht verstehen kann, da eine Interaktion nur über die Knöpfe möglich war. Die Ergebnisse zeigen, dass durchaus Beziehungen aufgebaut werden und lassen Schlüsse über die soziale Natur des Menschen zu

    Lass die Ohren nicht hängen! Eine Studie zur Wirkung der Ohrensprache eines Kommunikationsroboters in Hasenform

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    Im Folgenden werden die Ergebnisse einer Studie über die Wirkung des nonverbalen Verhaltens des Kommunikationsroboters Nabaztag und deren Implikation für das Nutzererleben dargestellt. 100 Probanden in Deutschland wurden Fotos des Hasen gezeigt, auf denen dieser verschiedene Ohrenpositionen hatte. Die Ergebnisse zeigen, dass mit den Positionen der Ohren, dem Hasen verschiedene Gefühlszustände zugeschrieben werden. Diese Ergebnisse sind vor dem Hintergrund eines gezielten matchings zwischen verbalen und nonverbalen Kommunikationsinhalten, aber auch für ein stimmiges Nutzererleben, und damit für den Nutzungsspaß, von essentieller Bedeutung

    Ethical Decision Making and Leadership Stress

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    The theme of this entry is how ethical decisionmaking is influenced by leadership stress. From a traditional point of view, stress is seen as a potential threat to leaders’ ethical decisions (Selart and Johansen 2011). There is substantial evidence suggesting that stress has a negative impact on leaders’ cognition and information processing, leading to errors and biases in their decisionmaking. However, it must be pointed out that in many types of professions (e.g., chief pilots, chief surgeons, and chief fire officers) leaders are more or less bound to develop advanced levels of stresstolerance in order to function ethically. This implies that stress does not always have to result in unethical decisions among leaders (Klein 1996). The structure of this entry is organized such that its first part is devoted to clarification of the relationship between ethical decision-making and leadership, while the second part is focused on how stress adds to this relationship

    A theoretical and empirical investigation of nutritional label use

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    Due in part to increasing diet-related health problems caused, among others, by obesity, nutritional labelling has been considered important, mainly because it can provide consumers with information that can be used to make informed and healthier food choices. Several studies have focused on the empirical perspective of nutritional label use. None of these studies, however, have focused on developing a theoretical economic model that would adequately describe nutritional label use based on a utility theoretic framework. We attempt to fill this void by developing a simple theoretical model of nutritional label use, incorporating the time a consumer spends reading labels as part of the food choice process. The demand equations of the model are then empirically tested. Results suggest the significant role of several variables that flow directly from the model which, to our knowledge, have not been used in any previous empirical work

    Skin Lesion Segmentation Ensemble with Diverse Training Strategies

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    This paper presents a novel strategy to perform skin lesion segmentation from dermoscopic images. We design an effective segmentation pipeline, and explore several pre-training methods to initialize the features extractor, highlighting how different procedures lead the Convolutional Neural Network (CNN) to focus on different features. An encoder-decoder segmentation CNN is employed to take advantage of each pre-trained features extractor. Experimental results reveal how multiple initialization strategies can be exploited, by means of an ensemble method, to obtain state-of-the-art skin lesion segmentation accuracy

    Building and sustaining Work Engagement – A participatory action intervention to increase Work Engagement in nursing staff

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    This study evaluated whether a participatory action research intervention with nursing staff on acute care older people NHS wards in the UK was effective for increasing work engagement. Mediation analyses between job resources, (social support, influence in decision-making), job demands, work-related needs (autonomy, competence, relatedness), and work engagement explored the presumed psychological mechanisms underlying the intervention. A nonrandomised, matched control group, pre-test, post-test design involved three intervention and five control wards. A significant decrease in relatedness, and a borderline significant decrease in competence, was observed in the intervention group compared to the control group, with no effect on work engagement (N=45). Work-related needs mediated between resources and work engagement, supporting the Job Demands-Resources model and Self-Determination Theory as an underlying explanatory theory. Intervention implementation was difficult, highlighting the need for participant and organisational readiness for change, and strong management support. This is the first known study to apply participatory techniques to increase work engagement in nursing staff and explore the underlying explanatory psychological mechanisms, offering a novel means of taking work engagement research forward. Crucially, it highlights the challenges involved in intervention research and the importance of including evaluations of intervention implementation alongside statistical evaluations to avoid erroneous conclusions

    Extraction of specific parameters for skin tumour classification

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    In this paper, a methodological approach to the classification of tumour skin lesions in dermoscopy images is presented. Melanomas are the most malignant skin tumours. They grow in melanocytes, the cells responsible for pigmentation. This type of cancer is increasing rapidly; its related mortality rate is increasing more modestly, and inversely proportional to the thickness of the tumour. The mortality rate can be decreased by earlier detection of suspicious lesions and better prevention. Using skin tumour features such as colour, symmetry and border regularity, an attempt is made to determine if the skin tumour is a melanoma or a benign tumour. In this work, we are interested in extracting specific attributes which can be used for computer-aided diagnosis of melanoma, especially among general practitioners. In the first step, we eliminate surrounding hair in order to eliminate the residual noise. In the second step, an automatic segmentation is applied to the image of the skin tumour. This method reduces a colour image into an intensity image and approximately segments the image by intensity thresholding. Then, it refines the segmentation using the image edges, which are used to localize the boundary in that area of the skin. This step is essential to characterize the shape of the lesion and also to locate the tumour for analysis. Then, a sequences of transformations is applied to the image to measure a set of attributes (A: asymmetry, B: border, C: colour and D: diameter) which contain sufficient information to differentiate a melanoma from benign lesions. Finally, the various signs of specific lesion (ABCD) are provided to an artificial neural network to differentiate between malignant tumours and benign lesions
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