259 research outputs found

    Focusing computational visual attention in multi-modal human-robot interaction

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    Identifying verbally and non-verbally referred-to objects is an im-portant aspect of human-robot interaction. Most importantly, it is essential to achieve a joint focus of attention and, thus, a natural interaction behavior. In this contribution, we introduce a saliency-based model that reflects how multi-modal referring acts influence the visual search, i.e. the task to find a specific object in a scene. Therefore, we combine positional information obtained from point-ing gestures with contextual knowledge about the visual appear-ance of the referred-to object obtained from language. The avail-able information is then integrated into a biologically-motivated saliency model that forms the basis for visual search. We prove the feasibility of the proposed approach by presenting the results of an experimental evaluation

    In vitro biotransformation assays using fish liver cells: Comparing rainbow trout and carp hepatocytes.

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    Biotransformation assays using primary hepatocytes from rainbow trout, Oncorhynchus mykiss, were validated as a reliable in vitro tool to predict in vivo bioconcentration factors (BCF) of chemicals in fish. Given the pronounced interspecies differences of chemical biotransformation, the present study aimed to compare biotransformation rate values and BCF predictions obtained with hepatocytes from the cold-water species, rainbow trout, to data obtained with hepatocytes of the warm-water species, common carp (Cyprinus carpio). In a first step, we adapted the protocol for the trout hepatocyte assay, including the cryopreservation method, to carp hepatocytes. The successful adaptation serves as proof of principle that the in vitro hepatocyte biotransformation assays can be technically transferred across fish species. In a second step, we compared the in vitro intrinsic clearance rates (CLin vitro, int) of two model xenobiotics, benzo[a]pyrene (BaP) and methoxychlor (MXC), in trout and carp hepatocytes. The in vitro data were used to predict in vivo biotransformation rate constants (kB) and BCFs, which were then compared to measured in vivo kB and BCF values. The CLin vitro, int values of BaP and MXC did not differ significantly between trout and carp hepatocytes, but the predicted BCF values were significantly higher in trout than in carp. In contrast, the measured in vivo BCF values did not differ significantly between the two species. A possible explanation of this discrepancy is that the existing in vitro-in vivo prediction models are parameterized only for trout but not for carp. Therefore, future research needs to develop species-specific extrapolation models

    Saliency-based identification and recognition of pointed-at objects

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    Abstract — When persons interact, non-verbal cues are used to direct the attention of persons towards objects of interest. Achieving joint attention this way is an important aspect of natural communication. Most importantly, it allows to couple verbal descriptions with the visual appearance of objects, if the referred-to object is non-verbally indicated. In this contri-bution, we present a system that utilizes bottom-up saliency and pointing gestures to efficiently identify pointed-at objects. Furthermore, the system focuses the visual attention by steering a pan-tilt-zoom camera towards the object of interest and thus provides a suitable model-view for SIFT-based recognition and learning. We demonstrate the practical applicability of the proposed system through experimental evaluation in different environments with multiple pointers and objects

    Auxiliary particle theory of threshold singularities in photoemission and X-ray absorption spectra: Test of a conserving T-matrix approximation

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    We calculate the exponents of the threshold singularities in the photoemission spectrum of a deep core hole and its X-ray absorption spectrum in the framework of a systematic many-body theory of slave bosons and pseudofermions (for the empty and occupied core level). In this representation, photoemission and X-ray absorption can be understood on the same footing; no distinction between orthogonality catastrophe and excitonic effects is necessary. We apply the conserving slave particle T-matrix approximation (CTMA), recently developed to describe both Fermi and non-Fermi liquid behavior systems with strong local correlations, to the X-ray problem as a test case. The numerical results for both photoemission and X-ray absorption are found to be in agreement with the exact infrared powerlaw behavior in the weak as well as in the strong coupling regions. We point out a close relation of the CTMA with the parquet equation approach of Nozi{\`e}res et al.Comment: 10 pages, 9 figures, published versio

    Anderson impurity model at finite Coulomb interaction U: generalized Non-crossing Approximation

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    We present an extension of the non-crossing approximation (NCA), which is widely used to calculate properties of Anderson impurity models in the limit of infinite Coulomb repulsion UU\to\infty, to the case of finite UU. A self-consistent conserving pseudo-particle representation is derived by symmetrizing the usual NCA diagrams with respect to empty and doubly occupied local states. This requires an infinite summation of skeleton diagrams in the generating functional thus defining the ``Symmetrized finite-U NCA'' (SUNCA). We show that within SUNCA the low energy scale TKT_K (Kondo temperature) is correctly obtained, in contrast to other simpler approximations discussed in the literature.Comment: 7 pages, 6 figure

    Single-Molecule Imaging Reveals Aβ42:Aβ40 Ratio-Dependent Oligomer Growth on Neuronal Processes

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    AbstractSoluble oligomers of the amyloid-β peptide have been implicated as proximal neurotoxins in Alzheimer’s disease. However, the identity of the neurotoxic aggregate(s) and the mechanisms by which these species induce neuronal dysfunction remain uncertain. Physiologically relevant experimentation is hindered by the low endogenous concentrations of the peptide, the metastability of Aβ oligomers, and the wide range of observed interactions between Aβ and biological membranes. Single-molecule microscopy represents one avenue for overcoming these challenges. Using this technique, we find that Aβ binds to primary rat hippocampal neurons at physiological concentrations. Although amyloid-β(1–40) as well as amyloid-β(1–42) initially form larger oligomers on neurites than on glass slides, a 1:1 mix of the two peptides result in smaller neurite-bound oligomers than those detected on-slide or for either peptide alone. With 1 nM peptide in solution, Aβ40 oligomers do not grow over the course of 48 h, Aβ42 oligomers grow slightly, and oligomers of a 1:1 mix grow substantially. Evidently, small Aβ oligomers are capable of binding to neurons at physiological concentrations and grow at rates dependent on local Aβ42:Aβ40 ratios. These results are intriguing in light of the increased Aβ42:Aβ40 ratios shown to correlate with familial Alzheimer’s disease mutations

    Development of a configurator of support systems for making strategic decisions

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    The results of creating an environment for developing strategic decision support systems are presented. The software is implemented on the basis of the 1C: 8.3 technology platform. The environment allows the construction of decision support systems for the strategic management of socio-economic systems of various kinds based on typical tools that allow you to work with expert knowledge

    Symmetry breaking in the Hubbard model at weak coupling

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    The phase diagram of the Hubbard model is studied at weak coupling in two and three spatial dimensions. It is shown that the Neel temperature and the order parameter in d=3 are smaller than the Hartree-Fock predictions by a factor of q=0.2599. For d=2 we show that the self-consistent (sc) perturbation series bears no relevance to the behavior of the exact solution of the Hubbard model in the symmetry-broken phase. We also investigate an anisotropic model and show that the coupling between planes is essential for the validity of mean-field-type order parameters

    Преступления в таможенной сфере: характеристика, выявление, ответственность

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    Объектом исследования является таможенный орган как средство обеспечения экономической безопасности. Цель работы - выявление проблем, возникающих у таможенных органов, как органов дознания при расследовании преступлений в сфере экономической деятельности и разработка рекомендаций, направленных на повышение эффективности правоохранительной деятельности таможенных органов как органов дознания. В процессе исследования был проведен анализ нормативно-правовой базы, регулирующей деятельность таможенных органов, а также практика расследования уголовных дел. В результате исследования были выявлены проблемы, возникающие у таможенных органов при расследовании преступлений и предложены рекомендации по решению этих проблем.The object of the research is customs authorities as tool of providing of economic safety. The goal of the work is the identification of problems, which customs authorities face while the process of investigation of crimes in economic sphere and developing some recommendations aimed to raise the efficiency of customs authorities’ activity. In the researching process there was an analysis of the regulatory framework, which adjusts the customs authorities’ activity and the practice of investigation of crimes in economic sphere. As a result of the research some problems, which customs authorities face while the process of investigation, were revealed and there are some offers aimed to solve this problems
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