Browsing by Author "Ertl, Thomas"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Bird's-Eye - Large-Scale Visual Analytics of City Dynamics using Social Location Data
    (The Eurographics Association and John Wiley & Sons Ltd., 2019) Krueger, Robert; Han, Qi; Ivanov, Nikolay; Mahtal, Sanae; Thom, Dennis; Pfister, Hanspeter; Ertl, Thomas; Gleicher, Michael and Viola, Ivan and Leitte, Heike
    The analysis of behavioral city dynamics, such as temporal patterns of visited places and citizens' mobility routines, is an essential task for urban and transportation planning. Social media applications such as Foursquare and Twitter provide access to large-scale and up-to-date dynamic movement data that not only help to understand the social life and pulse of a city but also to maintain and improve urban infrastructure. However, the fast growth rate of this data poses challenges for conventional methods to provide up-to-date, flexible analysis. Therefore, planning authorities barely consider it. We present a system and design study to leverage social media data that assist urban and transportation planners to achieve better monitoring and analysis of city dynamics such as visited places and mobility patterns in large metropolitan areas. We conducted a goal-and-task analysis with urban planning experts. To address these goals, we designed a system with a scalable data monitoring back-end and an interactive visual analytics interface. The monitoring component uses intelligent pre-aggregation to allow dynamic queries in near real-time. The visual analytics interface leverages unsupervised learning to reveal clusters, routines, and unusual behavior in massive data, allowing to understand patterns in time and space. We evaluated our approach based on a qualitative user study with urban planning experts which demonstrates that intuitive integration of advanced analytical tools with visual interfaces is pivotal in making behavioral city dynamics accessible to practitioners. Our interviews also revealed areas for future research.
  • Thumbnail Image
    Item
    Efficient Sphere Rendering Revisited
    (The Eurographics Association, 2023) Gralka, Patrick; Reina, Guido; Ertl, Thomas; Bujack, Roxana; Pugmire, David; Reina, Guido
    Glyphs are an intuitive way of displaying the results of atomistic simulations, usually as spheres. Raycasting of camera-aligned billboards is considered the state-of-the-art technique to render large sets of spheres in a rasterization-based pipeline since the approach was first proposed by Gumhold. Over time various acceleration techniques have been proposed, such as the rendering of point primitives as billboards, which are trivial to rasterize and avoid a high workload in the vertex pipeline. Other techniques attempt to optimize data upload and access patterns in shader programs, both relevant aspects for dynamic data. Recent advances in graphics hardware raise the question of whether these optimizations are still valid. We evaluate several rendering and data access scheme combinations on real-world datasets and derive recommendations for efficient rasterization-based sphere rendering.
  • Thumbnail Image
    Item
    Molecular Sombreros: Abstract Visualization of Binding Sites within Proteins
    (The Eurographics Association, 2019) Schatz, Karsten; Krone, Michael; Bauer, Tabea L.; Ferrario, Valerio; Pleiss, Jürgen; Ertl, Thomas; Kozlíková, Barbora and Linsen, Lars and Vázquez, Pere-Pau and Lawonn, Kai and Raidou, Renata Georgia
    We present a novel abstract visualization for the binding sites of proteins. Binding sites play an essential role in enzymatic reactions and are, thus, often investigated in structural biology. They are typically located within cavities. The shape and properties of the cavity influence whether and how easily a substrate can reach the active site where the reaction is triggered. Molecular surface visualizations can help to analyze the accessibility of binding sites, but are typically prone to visual clutter. Our novel abstract visualization shows the cavity containing the binding site as well as the surface region directly surrounding the cavity entrance in a simplified manner. The resulting visualization resembles a hat, where the brim depicts the surrounding surface region and the crown the cavity. Hence, we dubbed our abstraction Molecular Sombrero, using the Spanish term for 'hat'. Our abstraction is less cluttered than traditional molecular surface visualizations. It highlights important parameters, like cavity diameter, by mapping them to the shape of the sombrero. The visual abstraction also facilitates an easy side-by-side comparison of different data sets. We show the applicability of our Molecular Sombreros to different real-world use cases.
  • Thumbnail Image
    Item
    Real-time High-resolution Visualisation
    (The Eurographics Association, 2020) Frieß, Florian; Müller, Christoph; Ertl, Thomas; Krüger, Jens and Niessner, Matthias and Stückler, Jörg
    While visualisation often strives for abstraction, the interactive exploration of large scientific data sets like densely sampled 3D fields or massive particle data sets still benefits from rendering their graphical representation in large detail on high-resolution displays such as Powerwalls or tiled display walls driven by multiple GPUs or even GPU clusters. Such visualisation systems are typically rather unique in their setup of hardware and software which makes transferring a visualisation application from one high-resolution system to another one a complicated task. As more and more such visualisation systems get installed, collaboration becomes desirable in the sense of sharing such a visualisation running on one site in real time with another highresolution display on a remote site while at the same time communicating via video and audio. Since typical video conference solutions or web-based collaboration tools often cannot deal with resolutions exceeding 4K, with stereo displays or with multi- GPU setups, we designed and implemented a new system based on state-of-the-art hardware and software technologies to transmit high-resolution visualisations including video and audio streams via the internet to remote large displays and back. Our system architecture is built on efficient capturing, encoding and transmission of pixel streams and thus supports a multitude of configurations combining audio and video streams in a generic approach.
  • Thumbnail Image
    Item
    Visual Analysis of Large‐Scale Protein‐Ligand Interaction Data
    (© 2021 Eurographics ‐ The European Association for Computer Graphics and John Wiley & Sons Ltd, 2021) Schatz, Karsten; Franco‐Moreno, Juan José; Schäfer, Marco; Rose, Alexander S.; Ferrario, Valerio; Pleiss, Jürgen; Vázquez, Pere‐Pau; Ertl, Thomas; Krone, Michael; Benes, Bedrich and Hauser, Helwig
    When studying protein‐ligand interactions, many different factors can influence the behaviour of the protein as well as the ligands. Molecular visualisation tools typically concentrate on the movement of single ligand molecules; however, viewing only one molecule can merely provide a hint of the overall behaviour of the system. To tackle this issue, we do not focus on the visualisation of the local actions of individual ligand molecules but on the influence of a protein and their overall movement. Since the simulations required to study these problems can have millions of time steps, our presented system decouples visualisation and data preprocessing: our preprocessing pipeline aggregates the movement of ligand molecules relative to a receptor protein. For data analysis, we present a web‐based visualisation application that combines multiple linked 2D and 3D views that display the previously calculated data The central view, a novel enhanced sequence diagram that shows the calculated values, is linked to a traditional surface visualisation of the protein. This results in an interactive visualisation that is independent of the size of the underlying data, since the memory footprint of the aggregated data for visualisation is constant and very low, even if the raw input consisted of several terabytes.
  • Thumbnail Image
    Item
    Web-based Volume Rendering using Progressive Importance-based Data Transfer
    (The Eurographics Association, 2018) Mwalongo, Finian; Krone, Michael; Reina, Guido; Ertl, Thomas; Beck, Fabian and Dachsbacher, Carsten and Sadlo, Filip
    WebGL 2.0 makes it possible to implement efficient volume rendering that runs in browsers using 3D textures and complex fragment shaders. However, a typical bottleneck for web-based volume rendering is the size of the volumetric data sets. Transferring these data to the client for rendering can take a substantial amount of time, depending on the network speed. This can introduce latency that can in turn affect interactive rendering at the client. We address this challenge by introducing a multi-resolution bricked volume rendering, where data is transferred progressively. Similar to MIP-Mapping, the volume data is divided into multiple levels of detail. Each level of detail is broken down into bricks. The client requests the data brick by brick starting with the lowest resolution and renders each brick immediately as it is received. The 3D volume texture is updated as bricks with higher resolution are received asynchronously from the server. The advantages of this algorithm are that it reduces latency, the user can see at least a reduced-detail version of the data almost immediately, and the application always stays responsive while the data is updated. We also implemented a prioritization scheme for the bricks, where each brick can be assigned an importance value. Using this information, the client can request more important bricks first. Furthermore, we investigated the influence of data compression on the transfer and processing times.