956 research outputs found

    Virtual competitors influence rowers

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    Highly immersive environments for sports simulation can help elucidate if and how athletes perform under high pressure situations. We used a rowing simulator with a CAVE setup to test the influence of virtual competitors on 10 experienced rowers. All participants were using the simulator for the first time. The objective was to assess the degree of presence by quantifying how the actions of the virtual competitors triggered behavioral changes in the experienced rowers. The participants completed a virtual 2000 m race with two competing boats, one being behind and one ahead of the participant. For two trials, each boat would come closer to the participant without overtaking, resulting in four experimental conditions. The behavior of the participants was assessed with biomechanical variables, questionnaires, and an interview after the race. Behavioral changes were detected with statistically significant differences in the extracted variables of oar angles, timing variables, velocities, and work. The results for biomechanical variables indicate individual response patterns depending on perception of competitors and self-confidence. Self-reporting indicated a high degree of presence for most participants. Overall, the experimental paradigm worked but was compromised by perceptive and subjective factors. In future, the setup will be used to investigate rowing performance further with a focus on motor learning and training of pressure situations

    A plug and play spoken dialogue interface for smart environments

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-540-24630-5_44Proceedings of 5th International Conference, CICLing 2004 Seoul, Korea, February 15-21, 2004In this paper we present a plug and play dialogue system for smart environments. The environment description and its state are stored on a domain ontology. This ontology is formed by entities that represent real world contextual information and abstract concepts. This information is complemented with linguistic parts that allow to automatically create a spoken interface for the environment. The spoken interface is based on multiple dialogues, related to every ontology entity with linguistic information. Firstly, the dialogue system creates appropriate grammars for the dialogues. Secondly, it creates the dialogue parts, employing a tree structure. Grammars support the recognition process and the dialogue tree supports the interpretation and generation processes. The system is being tested with a prototype formed by a living room. Users may interact with and modify the physical state of this living room environment by means of the spoken dialogue interface.This paper has been sponsored by the Spanish Ministry of Science and Technology, project number TIC2000-046

    Inconsistency of the MLE for the joint distribution of interval censored survival times and continuous marks

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    This paper considers the nonparametric maximum likelihood estimator (MLE) for the joint distribution function of an interval censored survival time and a continuous mark variable. We provide a new explicit formula for the MLE in this problem. We use this formula and the mark specific cumulative hazard function of Huang and Louis (1998) to obtain the almost sure limit of the MLE. This result leads to necessary and sufficient conditions for consistency of the MLE which imply that the MLE is inconsistent in general. We show that the inconsistency can be repaired by discretizing the marks. Our theoretical results are supported by simulations.Comment: 27 pages, 4 figure

    Optimal Concentration of Information Content For Log-Concave Densities

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    An elementary proof is provided of sharp bounds for the varentropy of random vectors with log-concave densities, as well as for deviations of the information content from its mean. These bounds significantly improve on the bounds obtained by Bobkov and Madiman ({\it Ann. Probab.}, 39(4):1528--1543, 2011).Comment: 15 pages. Changes in v2: Remark 2.5 (due to C. Saroglou) added with more general sufficient conditions for equality in Theorem 2.3. Also some minor corrections and added reference

    Release of cell wall phenolic esters during hydrothermal pretreatment of rice husk and rice straw

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    Background: Rice husk and rice straw represent promising sources of biomass for production of renewable fuels and chemicals. For efficient utilisation, lignocellulosic components must first be pretreated to enable efficient enzymatic saccharification and subsequent fermentation. Existing pretreatments create breakdown products such as sugar-derived furans, and lignin-derived phenolics that inhibit enzymes and fermenting organisms. Alkali pretreatments have also been shown to release significant levels of simple, free phenolics such as ferulic acid that are normally esterified to cell wall polysaccharides in the intact plant. These phenolics have recently been found to have considerable inhibitory properties. The aim of this research has been to establish the extent to which such free phenolic acids are also released during hydrothermal pretreatment of rice straw (RS) and rice husk (RH). Results: RS and RH were subjected to hydrothermal pretreatments over a wide range of severities (1.57–5.45). FTIR analysis showed that the pretreatments hydrolysed and solubilised hemicellulosic moieties, leading to an enrichment of lignin and crystalline cellulose in the insoluble residue. The residues also lost the capacity for UV autofluorescence at pH 7 or pH 10, indicating the breakdown or release of cell wall phenolics. Saponification of raw RS and RH enabled identification and quantification of substantial levels of simple phenolics including ferulic acid (tFA), coumaric acid (pCA) and several diferulic acids (DiFAs) including 8-O-4′-DiFA, 8,5′-DiFA and 5,5′-DiFA. RH had higher levels of pCA and lower levels of tFA and DiFAs compared with RS. Assessment of the pretreatment liquors revealed that pretreatment-liberated phenolics present were not free but remained as phenolic esters (at mM concentrations) that could be readily freed by saponification. Many were lost, presumably through degradation, at the higher severities. Conclusion: Differences in lignin, tFA, DiFAs and pCA between RS and RH reflect differences in cell wall physiology, and probably contribute to the higher recalcitrance of RH compared with RS. Hydrothermal pretreatments, unlike alkali pretreatments, release cinnamic acid components as esters. The potential for pretreatment-liberated phenolic esters to be inhibitory to fermenting microorganisms is not known. However, the present study shows that they are found at concentrations that could be significantly inhibitory if released as free forms by enzyme activity

    Wheat glutenin subunits and dough elasticity: findings of the EUROWHEAT project

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    Detailed studies of wheat glutenin subunits have provided novel details of their molecular structures and interactions which allow the development of a model to explain their role in determining the visco-elastic properties of gluten and dough. The construction and analysis of near-isogenic and transgenic lines expressing novel subunit combinations or increased amounts of specific subunits allows differences in gluten properties to be related to the structures and properties of individual subunits, with potential benefits for the production of cultivars with improved properties for food processing or novel end user

    Characterisation of lignocellulosic sugars from municipal solid waste residue.

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    Municipal solid waste (MSW) contains significant quantities of plant-derived carbohydrates which have the potential to be exploited as a biomass source. This study evaluated the chemical composition and fractionation of MSW water-insoluble organic matter remaining after recycling of other components (MSWR). The organic matter was prepared as a dry, alcohol insoluble residue (MSWR-AIR, comprising w = 6% of original MSW) and size fractionated into fractions A, B, C & D. Carbohydrates were present in all the sub-fractions, comprising up to w = 54%; their complexity was also assessed by FT-IR spectroscopy. The lignin content in the samples ranged from w = 11–22%. The most carbohydrate-rich subfraction (C; w = 4% original MSW) was sequentially extracted to provide information on the likely constituent cell wall-derived polymers, sugar compositions and uronic acid content. The results indicate that approximately w = 25% of the MSWR-AIR comprises glucose, which appears to be mostly cellulosic in origin. The results are discussed in relation to the potential for exploitation

    D-optimal designs via a cocktail algorithm

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    A fast new algorithm is proposed for numerical computation of (approximate) D-optimal designs. This "cocktail algorithm" extends the well-known vertex direction method (VDM; Fedorov 1972) and the multiplicative algorithm (Silvey, Titterington and Torsney, 1978), and shares their simplicity and monotonic convergence properties. Numerical examples show that the cocktail algorithm can lead to dramatically improved speed, sometimes by orders of magnitude, relative to either the multiplicative algorithm or the vertex exchange method (a variant of VDM). Key to the improved speed is a new nearest neighbor exchange strategy, which acts locally and complements the global effect of the multiplicative algorithm. Possible extensions to related problems such as nonparametric maximum likelihood estimation are mentioned.Comment: A number of changes after accounting for the referees' comments including new examples in Section 4 and more detailed explanations throughou

    Закономерности изменения физико-механических свойств сплава Zr-1%Nb при комплексном ионно-плазменном модифицировании поверхности и наводороживании

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    В работе были изучены особенности изменения морфологии, структуры и физико-механических свойств циркониевого сплава Zr-1%Nb, подвергнутого комплексному ионно-плазменному модифицированию поверхности методами плазменно-иммерсионной ионной имплантации титана и осаждения покрытий нитрида титана. Показана высокая эффективность защиты сформированных структур от проникновения водорода в циркониевый сплав. Изучены механизмы сорбции и захвата водорода в титансодержащем модифицированном слое.In the present work, the features of the change in the morphology, structure, and physico-mechanical properties of zirconium alloy Zr-1%Nb subjected to complex ion-plasma surface modification by the methods of plasma-immersion titanium ion implantation and deposition of titanium nitride coatings were studied. The high protective properties of the formed structures against hydrogen permeation into the zirconium alloy is shown. Mechanisms of sorption and capture of hydrogen in a titanium-doped modified layer are studied

    A specific case in the classification of woods by FTIR and chemometric: discrimination of Fagales from Malpighiales

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    Fourier transform infrared (FTIR) spectroscopic data was used to classify wood samples from nine species within the Fagales and Malpighiales using a range of multivariate statistical methods. Taxonomic classification of the family Fagaceae and Betulaceae from Angiosperm Phylogenetic System Classification (APG II System) was successfully performed using supervised pattern recognition techniques. A methodology for wood sample discrimination was developed using both sapwood and heartwood samples. Ten and eight biomarkers emerged from the dataset to discriminate order and family, respectively. In the species studied FTIR in combination with multivariate analysis highlighted significant chemical differences in hemicelluloses, cellulose and guaiacyl (lignin) and shows promise as a suitable approach for wood sample classification
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