17,800 research outputs found

    The responses of people to virtual humans in an immersive virtual environment

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    This paper presents an experiment investigating the impact of behavior and responsiveness on social responses to virtual humans in an immersive virtual environment (IVE). A number of responses are investigated, including presence, copresence, and two physiological responses—heart rate and electrodermal activity (EDA). Our findings suggest that increasing agents’ responsiveness even on a simple level can have a significant impact on certain aspects of people’s social responses to humanoid agents. Despite being aware that the agents were computer-generated, participants with higher levels of social anxiety were significantly more likely to avoid “disturbing” them. This suggests that on some level people can respond to virtual humans as social actors even in the absence of complex interaction. Responses appear to be shaped both by the agents’ behaviors and by people’s expectations of the technology. Participants experienced a significantly higher sense of personal contact when the agents were visually responsive to them, as opposed to static or simply moving. However, this effect diminished with experienced computer users. Our preliminary analysis of objective heart-rate data reveals an identical pattern of responses

    Hilbert-Schmidt Separability Probabilities and Noninformativity of Priors

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    The Horodecki family employed the Jaynes maximum-entropy principle, fitting the mean (b_{1}) of the Bell-CHSH observable (B). This model was extended by Rajagopal by incorporating the dispersion (\sigma_{1}^2) of the observable, and by Canosa and Rossignoli, by generalizing the observable (B_{\alpha}). We further extend the Horodecki one-parameter model in both these manners, obtaining a three-parameter (b_{1},\sigma_{1}^2,\alpha) two-qubit model, for which we find a highly interesting/intricate continuum (-\infty < \alpha < \infty) of Hilbert-Schmidt (HS) separability probabilities -- in which, the golden ratio is featured. Our model can be contrasted with the three-parameter (b_{q}, \sigma_{q}^2,q) one of Abe and Rajagopal, which employs a q(Tsallis)-parameter rather than α\alpha, and has simply q-invariant HS separability probabilities of 1/2. Our results emerge in a study initially focused on embedding certain information metrics over the two-level quantum systems into a q-framework. We find evidence that Srednicki's recently-stated biasedness criterion for noninformative priors yields rankings of priors fully consistent with an information-theoretic test of Clarke, previously applied to quantum systems by Slater.Comment: 26 pages, 12 figure

    A priori probability that a qubit-qutrit pair is separable

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    We extend to arbitrarily coupled pairs of qubits (two-state quantum systems) and qutrits (three-state quantum systems) our earlier study (quant-ph/0207181), which was concerned with the simplest instance of entangled quantum systems, pairs of qubits. As in that analysis -- again on the basis of numerical (quasi-Monte Carlo) integration results, but now in a still higher-dimensional space (35-d vs. 15-d) -- we examine a conjecture that the Bures/SD (statistical distinguishability) probability that arbitrarily paired qubits and qutrits are separable (unentangled) has a simple exact value, u/(v Pi^3)= >.00124706, where u = 2^20 3^3 5 7 and v = 19 23 29 31 37 41 43 (the product of consecutive primes). This is considerably less than the conjectured value of the Bures/SD probability, 8/(11 Pi^2) = 0736881, in the qubit-qubit case. Both of these conjectures, in turn, rely upon ones to the effect that the SD volumes of separable states assume certain remarkable forms, involving "primorial" numbers. We also estimate the SD area of the boundary of separable qubit-qutrit states, and provide preliminary calculations of the Bures/SD probability of separability in the general qubit-qubit-qubit and qutrit-qutrit cases.Comment: 9 pages, 3 figures, 2 tables, LaTeX, we utilize recent exact computations of Sommers and Zyczkowski (quant-ph/0304041) of "the Bures volume of mixed quantum states" to refine our conjecture

    Spectroradiometric calibration of the Thematic Mapper and Multispectral Scanner system

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    The effects of the atmosphere on propagating radiation must be known in order to calibrate an in orbit sensor using ground based measurements. A set of model atmosphere parameters, applicable to the White Sands (New Mexico) area is defined with particular attention given to those parameters which are required as input to the Herman Code. The radial size distribution, refractive index, vertical distribution, and visibility of aerosols are discussed as well as the molecular absorbers in the visible and near IR wavelength which produce strong absorption lines. Solar irradiance is also considered

    Spectroradiometric calibration of the thematic mapper and multispectral scanner system

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    The results of an analysis that relates thematic mapper (TM) saturation level to ground reflectance, calendar date, latitude, and atmospheric condition is provided. A revised version of the preprint included with the last quarterly report is also provided for publication in the IEEE Transactions on Geoscience and Remote Sensing

    Spectroradiometric calibration of the Thematic Mapper and Multispectral Scanner system

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    The results of analyses of Thematic Mapper (TM) images acquired on July 8 and October 28, 1984, and of a check of the calibration of the 1.22-m integrating sphere at Santa Barbara Research Center (SBRC) are described. The results obtained from the in-flight calibration attempts disagree with the pre-flight calibrations for bands 2 and 4. Considerable effort was expended in an attempt to explain the disagreement. The difficult point to explain is that the difference between the radiances predicted by the radiative transfer code (the code radiances) and the radiances predicted by the preflight calibration (the pre-flight radiances) fluctuate with spectral band. Because the spectral quantities measured at White Sands show little change with spectral band, these fluctuations are not anticipated. Analyses of other targets at White Sands such as clouds, cloud shadows, and water surfaces tend to support the pre-flight and internal calibrator calibrations. The source of the disagreement has not been identified. It could be due to: (1) a computational error in the data reduction; (2) an incorrect assumption in the input to the radiative transfer code; or (3) incorrect operation of the field equipment

    Spectroradiometric calibration of the Thematic Mapper and Multispectral Scanner system

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    The newly built Caste spectropolarimeters gave satisfactory performance during tests in the solar radiometer and helicopter modes. A bandwidth normalization technique based on analysis of the moments of the spectral responsivity curves was used to analyze the spectral bands of the MSS and TM subsystems of LANDSAT 4 and 5 satellites. Results include the effective wavelength, the bandpass, the wavelength limits, and the normalized responsivity for each spectral channel. Temperature coefficients for TM PF channel 6 were also derived. The moments normalization method used yields sensor parameters whose derivation is independent of source characteristics (i.e., incident solar spectral irradiance, atmospheric transmittance, or ground reflectance). The errors expected using these parameters are lower than those expected using other normalization methods

    Spectroradiometric calibration of the thematic mapper and multispectral scanner system

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    The results obtained for the absolute calibration of TM bands 2, 3, and 4 are presented. The results are based on TM image data collected simultaneously with ground and atmospheric data at White Sands, New Mexico. Also discussed are the results of a moments analysis to determine the equivalent bandpasses, effective central wavelengths and normalized responses of the TM and MSS spectral bands; the calibration of the BaSO, plate used at White Sands; and future plans
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