ABSTRACT
Stripped envelope supernovae are a sub-class of core-collapse supernovae showing several stages of H/He shell stripping that determines the type: H-free/He-poor SNe are classified as Type ...Ic, H-poor/He-rich are Type Ib, and H/He-rich are Type IIb. Stripping H/He with only stellar wind requires significantly higher mass-loss rates than observed while binary-involved mass transfer may usually not strip enough to produce H/He free SNe. Type Ib/c SNe are sometimes found to include weak H/He transient lines as a product of a trace amount of H/He left over from stripping processes. The extent and mass of the H/He required to produce these lines is not well known. In this work, a 22 M⊙ progenitor model is stripped of the H/He shells in five steps prior to collapse and then exploded at four explosion energies. Requiring both optical and near-infrared He i lines for helium identification does not allow much He mass to be hidden in SE–SNE. Increasing the mass of He above the CO core delays the visibility of O i 7774 in early spectra. Our SN Ib-like models are capable of reproducing the spectral evolution of a set of observed SNe with reasonable estimated Ek accuracy. Our SN IIb-like models can partially reproduce low energy observed SN IIb, but we find no observed comparison for the SN IIb-like models with high Ek.
Real-Time Visual Analysis of High-Volume Social Media Posts Knittel, Johannes; Koch, Steffen; Tang, Tan ...
IEEE transactions on visualization and computer graphics,
2022-Jan., 2022-01-00, 2022-1-00, 20220101, Letnik:
28, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Breaking news and first-hand reports often trend on social media platforms before traditional news outlets cover them. The real-time analysis of posts on such platforms can reveal valuable and timely ...insights for journalists, politicians, business analysts, and first responders, but the high number and diversity of new posts pose a challenge. In this work, we present an interactive system that enables the visual analysis of streaming social media data on a large scale in real-time. We propose an efficient and explainable dynamic clustering algorithm that powers a continuously updated visualization of the current thematic landscape as well as detailed visual summaries of specific topics of interest. Our parallel clustering strategy provides an adaptive stream with a digestible but diverse selection of recent posts related to relevant topics. We also integrate familiar visual metaphors that are highly interlinked for enabling both explorative and more focused monitoring tasks. Analysts can gradually increase the resolution to dive deeper into particular topics. In contrast to previous work, our system also works with non-geolocated posts and avoids extensive preprocessing such as detecting events. We evaluated our dynamic clustering algorithm and discuss several use cases that show the utility of our system.
Temporal action localization aims to identify the boundaries and categories of actions in videos, such as scoring a goal in a football match. Single-frame supervision has emerged as a labor-efficient ...way to train action localizers as it requires only one annotated frame per action. However, it often suffers from poor performance due to the lack of precise boundary annotations. To address this issue, we propose a visual analysis method that aligns similar actions and then propagates a few user-provided annotations (e.g., boundaries, category labels) to similar actions via the generated alignments. Our method models the alignment between actions as a heaviest path problem and the annotation propagation as a quadratic optimization problem. As the automatically generated alignments may not accurately match the associated actions and could produce inaccurate localization results, we develop a storyline visualization to explain the localization results of actions and their alignments. This visualization facilitates users in correcting wrong localization results and misalignments. The corrections are then used to improve the localization results of other actions. The effectiveness of our method in improving localization performance is demonstrated through quantitative evaluation and a case study.
Foveated Encoding for Large High-Resolution Displays Friess, Florian; Braun, Matthias; Bruder, Valentin ...
IEEE transactions on visualization and computer graphics,
2021-Feb., 2021-Feb, 2021-2-00, 20210201, Letnik:
27, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Collaborative exploration of scientific data sets across large high-resolution displays requires both high visual detail as well as low-latency transfer of image data (oftentimes inducing the need to ...trade one for the other). In this work, we present a system that dynamically adapts the encoding quality in such systems in a way that reduces the required bandwidth without impacting the details perceived by one or more observers. Humans perceive sharp, colourful details, in the small foveal region around the centre of the field of view, while information in the periphery is perceived blurred and colourless. We account for this by tracking the gaze of observers, and respectively adapting the quality parameter of each macroblock used by the H.264 encoder, considering the so-called visual acuity fall-off. This allows to substantially reduce the required bandwidth with barely noticeable changes in visual quality, which is crucial for collaborative analysis across display walls at different locations. We demonstrate the reduced overall required bandwidth and the high quality inside the foveated regions using particle rendering and parallel coordinates.
In this manuscript, we review the evolution of atomistic visualization over the last 12 years and put the development of the community in context with our own efforts within the DFG collaborative ...research center 716. The goal is to provide a comprehensive summary of all relevant work that has been conducted under the auspices of project D.3. In this project, we focused on the visualization and analysis of particle-based data sets, and on how to bring these visualizations onto the workstation of domain scientists without the need for a large rendering infrastructure. We discuss how our decisions and goals evolved over time and show the success stories and publications. Finally, we give an outlook on the challenges that still require additional research and to which extent the requirements and constraints of current research have changed the way visualization works after these 12 years.
We developed a new visualization approach to gain a better understanding of the displacement of one fluid phase by another in porous media. This is based on a recent experimental parameter study with ...varying capillary numbers and viscosity ratios. We analyse the temporal evolution of characteristic values in this two‐phase flow scenario and discuss how to directly compare experiments across different temporal scales. To enable spatio‐temporal analysis, we introduce a new visual representation showing which paths through the porous medium were occupied and for how long. These transport networks allow to assess the impact of different acting forces and they are designed to yield expressive comparability and linking to the experimental parameter space both supported by additional visual cues. This joint work of porous media experts and visualization researchers yields new insights regarding two‐phase flow on the microscale, and our visualization approach contributes towards the overarching goal of the domain scientists to characterize porous media flow based on capillary numbers and viscosity ratios.
We developed a new visualization approach to gain a better understanding of the displacement of one fluid phase by another in porous media.
PDF
