258 research outputs found
Modèle de formation du flou d'une caméra rotative à bande et son impact sur la reconstruction 3D
L'imagerie panoramique permet d'élargir le champ visuel restreint des caméras standards. La reconstruction 3D d'une scène peut se faire à l'aide d'une ou plusieurs images panoramiques. Afin de reconstruire une scène en trois dimensions à partir d'images panoramiques, plusieurs méthodes existent. Dans ce document, nous nous intéressons à l'utilisation du flou comme indice de profondeur. Plus précisément, nous nous intéressons à la différence de flou proposée par Ziou et Deschênes en 1999 sur des images saisies à l'aide d'une caméra panoramique rotative à bande. Dans un premier temps, nous effectuons l'analyse du modèle de formation du flou d'une caméra rotative à bande et proposons une adaptation du modèle de formation d'une caméra standard dans le cas d'images formées à l'aide d'un capteur linéaire en rotation. Ce modèle adapté est ensuite utilisé pour modifier l'algorithme de reconstruction 3D par différence de flou de Ziou et Deschênes dans le cas d'images panoramiques capturées à l'aide d'une caméra rotative à bande. Nous montrons que cette adaptation nous permet d'obtenir, à partir d'images panoramiques, des résultats similaires à 98% à ce que donne l'algorithme de reconstruction original sur des images non panoramiques
Mutacin H-29B is identical to mutacin II (J-T8)
BACKGROUND: Streptococcus mutans produces bacteriocins named mutacins. Studies of mutacins have always been hampered by the difficulties in obtaining active liquid preparations of these substances. Some of them were found to be lantibiotics, defined as bacterial ribosomally synthesised lanthionine-containing peptides with antimicrobial activity. The goal of this study was to produce and characterize a new mutacin from S. mutans strain 29B, as it shows a promising activity spectrum against current human pathogens. RESULTS: Mutacin H-29B, produced by S. mutans strain 29B, was purified by successive hydrophobic chromatography from a liquid preparation consisting of cheese whey permeate (6% w/v) supplemented with yeast extract (2%) and CaCO(3 )(1%). Edman degradation revealed 24 amino acids identical to those of mutacin II (also known as J-T8). The molecular mass of the purified peptide was evaluated at 3246.08 ± 0.1 Da by MALDI-TOF MS. CONCLUSION: A simple procedure for production and purification of mutacins along with its characterization is presented. Our results show that the amino acid sequence of mutacin H-29B is identical to the already known mutacin II (J-T8) over the first 24 residues. S. mutans strains of widely different origins may thus produce very similar bacteriocins
Killer Apps: Developing Novel Applications That Enhance Team Coordination, Communication, and Effectiveness
As part of the Lorentz workshop, “Interdisciplinary Insights into Group and Team Dynamics,” held in Leiden, Netherlands, this article describes how Geeks and Groupies (computer and social scientists) may benefit from interdisciplinary collaboration toward the development of killer apps in team contexts that are meaningful and challenging for both. First, we discuss interaction processes during team meetings as a research topic for both Groupies and Geeks. Second, we highlight teamwork in health care settings as an interdisciplinary research challenge. Third, we discuss how an automated solution for optimal team design could benefit team effectiveness and feed into team-based interventions. Fourth, we discuss team collaboration in massive open online courses as a challenge for both Geeks and Groupies. We argue for the necessary integration of social and computational research insights and approaches. In the hope of inspiring future interdisciplinary collaborations, we develop criteria for evaluating killer apps—including the four proposed here—and discuss future research challenges and opportunities that potentially derive from these developments
Full moment tensor and source location inversion based on full waveform adjoint inversion: application at the Geysers geothermal field
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A Tool for the Automated Collection of Space Utilization Data: Three Dimensional Space Utilization Monitor
Space Human Factors and Habitability (SHFH) Element within the Human Research Program (HRP), in collaboration with the Behavioral Health and Performance (BHP) Element, is conducting research regarding Net Habitable Volume (NHV), the internal volume within a spacecraft or habitat that is available to crew for required activities, as well as layout and accommodations within that volume. NASA is looking for innovative methods to unobtrusively collect NHV data without impacting crew time. Data required includes metrics such as location and orientation of crew, volume used to complete tasks, internal translation paths, flow of work, and task completion times. In less constrained environments methods for collecting such data exist yet many are obtrusive and require significant postprocessing. Example technologies used in terrestrial settings include infrared (IR) retroreflective marker based motion capture, GPS sensor tracking, inertial tracking, and multiple camera filmography. However due to constraints of space operations many such methods are infeasible, such as inertial tracking systems which typically rely upon a gravity vector to normalize sensor readings, and traditional IR systems which are large and require extensive calibration. However multiple technologies have not yet been applied to space operations for these explicit purposes. Two of these include 3Dimensional Radio Frequency Identification RealTime Localization Systems (3D RFIDRTLS) and depth imaging systems which allow for 3D motion capture and volumetric scanning (such as those using IRdepth cameras like the Microsoft Kinect or Light Detection and Ranging / LightRadar systems, referred to as LIDAR)
A Tool for the Automated Collection of Space Utilization Data: Three Dimensional Space Utilization Monitor
Space Human Factors and Habitability (SHFH) Element within the Human Research Program (HRP) and the Behavioral Health and Performance (BHP) Element are conducting research regarding Net Habitable Volume (NHV), the internal volume within a spacecraft or habitat that is available to crew for required activities, as well as layout and accommodations within the volume. NASA needs methods to unobtrusively collect NHV data without impacting crew time. Data required includes metrics such as location and orientation of crew, volume used to complete tasks, internal translation paths, flow of work, and task completion times. In less constrained environments methods exist yet many are obtrusive and require significant post-processing. Examplesused in terrestrial settings include infrared (IR) retro-reflective marker based motion capture, GPS sensor tracking, inertial tracking, and multi-camera methods Due to constraints of space operations many such methods are infeasible. Inertial tracking systems typically rely upon a gravity vector to normalize sensor readings,and traditional IR systems are large and require extensive calibration. However, multiple technologies have not been applied to space operations for these purposes. Two of these include: 3D Radio Frequency Identification Real-Time Localization Systems (3D RFID-RTLS) Depth imaging systems which allow for 3D motion capture and volumetric scanning (such as those using IR-depth cameras like the Microsoft Kinect or Light Detection and Ranging / Light-Radar systems, referred to as LIDAR
Free Water in White Matter Differentiates Mci and ad From Control Subjects
Recent evidence shows that neuroinflammation plays a role in many neurological diseases including mild cognitive impairment (MCI) and Alzheimer\u27s disease (AD), and that free water (FW) modeling from clinically acquired diffusion MRI (DTI-like acquisitions) can be sensitive to this phenomenon. This FW index measures the fraction of the diffusion signal explained by isotropically unconstrained water, as estimated from a bi-tensor model. In this study, we developed a simple but powerful whole-brain FW measure designed for easy translation to clinical settings and potential use as a priori outcome measure in clinical trials. These simple FW measures use a safe white matter (WM) mask without gray matter (GM)/CSF partial volume contamination
Predicting Head Pose in Dyadic Conversation
Natural movement plays a significant role in realistic speech animation. Numerous studies have demonstrated the contribution visual cues make to the degree we, as human observers, find an animation acceptable. Rigid head motion is one visual mode that universally co-occurs with speech, and so it is a reasonable strategy to seek features from the speech mode to predict the head pose. Several previous authors have shown that prediction is possible, but experiments are typically confined to rigidly produced dialogue. Expressive, emotive and prosodic speech exhibit motion patterns that are far more difficult to predict with considerable variation in expected head pose. People involved in dyadic conversation adapt speech and head motion in response to the others’ speech and head motion. Using Deep Bi-Directional Long Short Term Memory (BLSTM) neural networks, we demonstrate that it is possible to predict not just the head motion of the speaker, but also the head motion of the listener from the speech signal
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High Altitude Aerial Natural Gas Leak Detection System
The objective of this program was to develop and demonstrate a cost-effective and power-efficient advanced standoff sensing technology able to detect and quantify, from a high-altitude (> 10,000 ft) aircraft, natural gas leaking from a high-pressure pipeline. The advanced technology is based on an enhanced version of the Remote Methane Leak Detector (RMLD) platform developed previously by Physical Sciences Inc. (PSI). The RMLD combines a telecommunications-style diode laser, fiber-optic components, and low-cost DSP electronics with the well-understood principles of Wavelength Modulation Spectroscopy (WMS), to indicate the presence of natural gas located between the operator and a topographic target. The transceiver transmits a laser beam onto a topographic target and receives some of the laser light reflected by the target. The controller processes the received light signal to deduce the amount of methane in the laser's path. For use in the airborne platform, we modified three aspects of the RMLD, by: (1) inserting an Erbium-doped optical fiber laser amplifier to increase the transmitted laser power from 10 mW to 5W; (2) increasing the optical receiver diameter from 10 cm to 25 cm; and (3) altering the laser wavelength from 1653 nm to 1618 nm. The modified RMLD system provides a path-integrated methane concentration sensitivity {approx}5000 ppm-m, sufficient to detect the presence of a leak from a high capacity transmission line while discriminating against attenuation by ambient methane. In ground-based simulations of the aerial leak detection scenario, we demonstrated the ability to measure methane leaks within the laser beam path when it illuminates a topographic target 2000 m away. We also demonstrated simulated leak detection from ranges of 200 m using the 25 cm optical receiver without the fiber amplifier
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