140 research outputs found

    QoE of cross-modally mapped Mulsemedia: an assessment using eye gaze and heart rate

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    A great deal of research effort has been put in exploring crossmodal correspondences in the field of cognitive science which refer to the systematic associations frequently made between different sensory modalities (e.g. high pitch is matched with angular shapes). However, the possibilities cross-modality opens in the digital world have been relatively unexplored. Therefore, we consider that studying the plasticity and the effects of crossmodal correspondences in a mulsemedia setup can bring novel insights about improving the human-computer dialogue and experience. Mulsemedia refers to the combination of three or more senses to create immersive experiences. In our experiments, users were shown six video clips associated with certain visual features based on color, brightness, and shape. We examined if the pairing with crossmodal matching sound and the corresponding auto-generated haptic effect, and smell would lead to an enhanced user QoE. For this, we used an eye-tracking device as well as a heart rate monitor wristband to capture users’ eye gaze and heart rate whilst they were experiencing mulsemedia. After each video clip, we asked the users to complete an on-screen questionnaire with a set of questions related to smell, sound and haptic effects targeting their enjoyment and perception of the experiment. Accordingly, the eye gaze and heart rate results showed significant influence of the cross-modally mapped multisensorial effects on the users’ QoE. Our results highlight that when the olfactory content is crossmodally congruent with the visual content, the visual attention of the users seems shifted towards the correspondent visual feature. Crosmodally matched media is also shown to result in an enhanced QoE compared to a video only condition

    Duality in Non-Trivially Compactified Heterotic Strings

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    We study the implications of duality symmetry on the analyticity properties of the partition function as it depends upon the compactification length. In order to obtain non-trivial compactifications, we give a physical prescription to get the Helmholtz free energy for any heterotic string supersymmetric or not. After proving that the free energy is always invariant under the duality transformation R→αâ€Č/(4R)R\rightarrow \alpha^{'}/(4R) and getting the zero temperature theory whose partition function corresponds to the Helmholtz potential, we show that the self-dual point R0=αâ€Č/2R_{0}=\sqrt{\alpha^{'}}/2 is a generic singularity as the Hagedorn one. The main difference between these two critical compactification radii is that the term producing the singularity at the self-dual point is finite for any R≠R0R \neq R_{0}. We see that this behavior at R0R_{0} actually implies a loss of degrees of freedom below that point.Comment: (Preprint No. FTUAM-92/12) 17 page

    The effect of mirabegron on energy expenditure and brown adipose tissue in healthy lean South Asian and Europid men

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    Aim: To compare the effects of cold exposure and the ÎČ3-adrenergic receptor agonist mirabegron on plasma lipids, energy expenditure and brown adipose tissue (BAT) activity in South Asians versus Europids. Materials and Methods: Ten lean Dutch South Asian (aged 18-30 years; body mass index [BMI] 18-25 kg/m2 ) and 10 age- and BMI-matched Europid men participated in a randomized, double-blinded, cross-over study consisting of three interventions: short-term (~ 2 hours) cold exposure, mirabegron (200 mg one dose p.o.) and placebo. Before and after each intervention, we performed lipidomic analysis in serum, assessed resting energy expenditure (REE) and skin temperature, and measured BAT fat fraction by magnetic resonance imaging. Results: In both ethnicities, cold exposure increased the levels of several serum lipid species, whereas mirabegron only increased free fatty acids. Cold exposure increased lipid oxidation in both ethnicities, while mirabegron increased lipid oxidation in Europids only. Cold exposure and mirabegron enhanced supraclavicular skin temperature in both ethnicities. Cold exposure decreased BAT fat fraction in both ethnicities. After the combination of data from both ethnicities, mirabegron decreased BAT fat fraction compared with placebo. Conclusions: In South Asians and Europids, cold exposure and mirabegron induced beneficial metabolic effects. When combining both ethnicities, cold exposure and mirabegron increased REE and lipid oxidation, coinciding with a higher supraclavicular skin temperature and lower BAT fat fraction.Diabetes Research Foundation Fellowship 2015.81.1808Netherlands CardioVascular Research Initiative: 'the Dutch Heart Foundation, Dutch Federation of University Medical Centers, the Netherlands Organisation for Health Research and Development and the Royal Netherlands Academy of Sciences' CVON2014-02 ENERGISE CVON2017-20 GENIUS-IIEuropean Union (EU) 602485European Research Council (NOMA-MRI) PCNR is an Established Investigator of the Netherlands Heart Foundation 2009T03

    Neural network modelling of RC deep beam shear strength

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    YesA 9 x 18 x 1 feed-forward neural network (NN) model trained using a resilient back-propagation algorithm and early stopping technique is constructed to predict the shear strength of deep reinforced concrete beams. The input layer covering geometrical and material properties of deep beams has nine neurons, and the corresponding output is the shear strength. Training, validation and testing of the developed neural network have been achieved using a comprehensive database compiled from 362 simple and 71 continuous deep beam specimens. The shear strength predictions of deep beams obtained from the developed NN are in better agreement with test results than those determined from strut-and-tie models. The mean and standard deviation of the ratio between predicted capacities using the NN and measured shear capacities are 1.028 and 0.154, respectively, for simple deep beams, and 1.0 and 0.122, respectively, for continuous deep beams. In addition, the trends ascertained from parametric study using the developed NN have a consistent agreement with those observed in other experimental and analytical investigations

    Calorimetric study of geopolymer binders based on natural pozzolan

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    This paper investigates the kinetics of geopolymerisation in an inorganic polymeric binder based on a natural pozzolan. The heat released by the exothermic geopolymerisation reaction process is monitored under isothermal temperature conditions, maintained in a differential scanning calorimeter using a water circulation cell. Calorimetric data are obtained isothermally at 65, 75, and 85 °C with various Na2O/Al2O3 and SiO2/Na2O molar ratios and in the presence and absence of small amounts of calcium aluminate cement (used as an efflorescence control admixture in these binder systems). The first stage of reaction, which is rapid and strongly exothermic, is shortened as the temperature increases. The total heat of reaction increases in the mixes containing calcium aluminate cement, but the apparent activation energy calculated using a pseudo-first-order reaction model is lower than without added calcium aluminate cement. At a constant overall SiO2/Na2O molar ratio, the apparent activation energy is decreased as the Na2O/Al2O3 molar ratio increases. Calcium aluminate cement, therefore, reduces the minimum energy required to initiate geopolymerisation reactions of this natural pozzolan and facilitates the progress of the reactions which lead to formation of a cementitious product

    The influence of rice husk ash addition on the properties of metakaolin-based geopolymers

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    This paper investigates the replacement of metakaolin (MK) with rice husk ash (RHA) in the production of alkali-activated binders or geopolymers. The influence of the RHA addition on compressive and flexural strength, as well as water absorption and apparent porosity were determined, in terms of the percentage of RHA in the mixture and molar ratios of the mixes. Fourier Transform Infrared (FTIR) spectroscopy and Energy Dispersive spectroscopy (EDS) were carried out to assess the changes in the microstructure of the geopolymer matrices with the RHA addition. Results have shown that RHA may be a supplementary precursor for geopolymers. The composition of the geopolymer matrices containing 0-40% RHA is very similar, which indicates that the additional Si provided by RHA is not incorporated to the geopolymer matrix. In addition, geopolymers with RHA content higher than 40% present a plastic behavior, characterized by extremely low strength and high deformation, which can be attributed to the formation of silica gel in formulations containing variable Si/Al ratio
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