351,293 research outputs found

    Automated Detection of Solar Eruptions

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    Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advancing our understanding the drivers of space weather. Both automated and visual identifications are currently used in identifying CMEs. To date, eruptions near the solar surface (which may be precursors to CMEs) have been identified primarily by visual inspection. Here we report on EruptionPatrol (EP): a software module that is designed to automatically identify eruptions from data collected by SDO/AIA. We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/sec and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.Comment: 6 pages, 4 figures, 7th Solar Information Processing Workshop, to appear in Space Weather and Space Climat

    Semantic multimedia remote display for mobile thin clients

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    Current remote display technologies for mobile thin clients convert practically all types of graphical content into sequences of images rendered by the client. Consequently, important information concerning the content semantics is lost. The present paper goes beyond this bottleneck by developing a semantic multimedia remote display. The principle consists of representing the graphical content as a real-time interactive multimedia scene graph. The underlying architecture features novel components for scene-graph creation and management, as well as for user interactivity handling. The experimental setup considers the Linux X windows system and BiFS/LASeR multimedia scene technologies on the server and client sides, respectively. The implemented solution was benchmarked against currently deployed solutions (VNC and Microsoft-RDP), by considering text editing and WWW browsing applications. The quantitative assessments demonstrate: (1) visual quality expressed by seven objective metrics, e.g., PSNR values between 30 and 42 dB or SSIM values larger than 0.9999; (2) downlink bandwidth gain factors ranging from 2 to 60; (3) real-time user event management expressed by network round-trip time reduction by factors of 4-6 and by uplink bandwidth gain factors from 3 to 10; (4) feasible CPU activity, larger than in the RDP case but reduced by a factor of 1.5 with respect to the VNC-HEXTILE

    Quantitative Differences in the Conversational Performance of People with Severe Expressive Aphasia Using Three Types of Visual Screen Displays on Speech Generating Devices

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    This multiple single-subject research study measured quantitative differences in communication success, communicator roles and act functions during dyadic conversational interactions between six people with severe aphasia and their peer communication partners across three conditions involving a type of augmentative communication intervention, speech generating devices (SGDs). Researchers assessed these variables across four conditions involving the message display of the SGD: no display (Condition A), visual scenes (contextual photographic) display (Condition B), Traditional Grid Display (Condition C), while participants engage in conversational story telling. This study is important because technology is currently being developed to assist people with aphasia to access messages stored on an SGD by activating photographic representations that access a set of spoken messages that are related to the photo. This contrasts with a more traditional method of representing messages, in which decontextual line drawings associated with individual concepts are displayed on the screen. Results from this study indicate that interactions between peer communication partners and people with aphasia can and do benefit from external, symbolic representation of messages on AAC devices. However, an unexpected finding was that given too much contextual information as with visual scenes, peer communication partners can deduce the content and context of the story, thereby being more apt to dominate the conversation than they are with no display

    Advances in Visual Methodology

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    In recent years we have witnessed a ‘visual turn’ in the social sciences, as an increasing number of scholars are engaging with visual methodologies for the collection, analysis, and display of both qualitative and quantitative data. To mention an example, video ethnography is gaining momentum across a range of disciplines, at a time when social scientists are increasingly concerned with capturing the minutiae and details of social practices. What is more, recent developments in information technology are extending the range of techniques for the capture and analysis of visual data, therefore opening up new possibilities for research and practice. It is no coincidence that several books on visual methodologies were published in the last ten years (Margolis & Pauwels, 2011; Rose, 2007; Van Leeuwen & Jewitt, 2001) and an entire volume on visual data analysis was included in the SAGE collection on qualitative research methods (Banks & Flick, 2007). But what is distinctive about Sarah Pink’s Advances in Visual Methodology is the attempt to establish visual methodology as an interdisciplinary field of practice, while recognizing the interconnectedness of theory, technology and methods

    Simulation Evaluation of Synthetic Vision as an Enabling Technology for Equivalent Visual Operations

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    Enhanced Vision (EV) and synthetic vision (SV) systems may serve as enabling technologies to meet the challenges of the Next Generation Air Transportation System (NextGen) Equivalent Visual Operations (EVO) concept ? that is, the ability to achieve or even improve on the safety of Visual Flight Rules (VFR) operations, maintain the operational tempos of VFR, and even, perhaps, retain VFR procedures independent of actual weather and visibility conditions. One significant challenge lies in the definition of required equipage on the aircraft and on the airport to enable the EVO concept objective. A piloted simulation experiment was conducted to evaluate the effects of the presence or absence of Synthetic Vision, the location of this information during an instrument approach (i.e., on a Head-Up or Head-Down Primary Flight Display), and the type of airport lighting information on landing minima. The quantitative data from this experiment were analyzed to begin the definition of performance-based criteria for all-weather approach and landing operations. Objective results from the present study showed that better approach performance was attainable with the head-up display (HUD) compared to the head-down display (HDD). A slight performance improvement in HDD performance was shown when SV was added, as the pilots descended below 200 ft to a 100 ft decision altitude, but this performance was not tested for statistical significance (nor was it expected to be statistically significant). The touchdown data showed that regardless of the display concept flown (SV HUD, Baseline HUD, SV HDD, Baseline HDD) a majority of the runs were within the performance-based defined approach and landing criteria in all the visibility levels, approach lighting systems, and decision altitudes tested. For this visual flight maneuver, RVR appeared to be the most significant influence in touchdown performance. The approach lighting system clearly impacted the pilot's ability to descend to 100 ft height above touchdown based on existing Federal Aviation Regulation (FAR) 91.175 using a 200 ft decision height, but did not appear to influence touchdown performance or approach path maintenanc

    Evaluation of force-torque displays for use with space station telerobotic activities

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    Recent experiments which addressed Space Station remote manipulation tasks found that tactile force feedback (reflecting forces and torques encountered at the end-effector through the manipulator hand controller) does not improve performance significantly. Subjective response from astronaut and non-astronaut test subjects indicated that force information, provided visually, could be useful. No research exists which specifically investigates methods of presenting force-torque information visually. This experiment was designed to evaluate seven different visual force-torque displays which were found in an informal telephone survey. The displays were prototyped in the HyperCard programming environment. In a within-subjects experiment, 14 subjects nullified forces and torques presented statically, using response buttons located at the bottom of the screen. Dependent measures included questionnaire data, errors, and response time. Subjective data generally demonstrate that subjects rated variations of pseudo-perspective displays consistently better than bar graph and digital displays. Subjects commented that the bar graph and digital displays could be used, but were not compatible with using hand controllers. Quantitative data show similar trends to the subjective data, except that the bar graph and digital displays both provided good performance, perhaps do to the mapping of response buttons to display elements. Results indicate that for this set of displays, the pseudo-perspective displays generally represent a more intuitive format for presenting force-torque information

    Wigner Ville Distribution in Signal Processing, using Scilab Environment

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    The Wigner Ville distribution offers a visual display of quantitative information about the way a signal’s energy is distributed in both, time and frequency. Through that, this distribution embodies the fundamentally concepts of the Fourier and time-domain analysis. The energy of the signal is distributed so that specific frequencies are localized in time by the group delay time and at specifics instants in time the frequency is given by the instantaneous frequency. The net positive volum of the Wigner distribution is numerically equal to the signal’s total energy. The paper shows the application of the Wigner Ville distribution, in the field of signal processing, using Scilab environment
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