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We describe a systematic approach for rendering time-varying simulation data produced by exa-scale simulations, using GPU workstations. The data sets we focus on use adaptive mesh refinement (AMR) to overcome memory bandwidth limitations by representing interesting regions in space with high detail. Particularly, our focus is on data sets where the AMR hierarchy is fixed and does not change over time. Our study is motivated by the NASA Exajet, a large computational fluid dynamics simulation of a civilian cargo aircraft that consists of 423 simulation time steps, each storing 2.5 GB of data per scalar field, amounting to a total of 4 TB. We present strategies for rendering this time series data set with smooth animation and at interactive rates using current generation GPUs. We start with an unoptimized baseline and step by step extend that to support fast streaming updates. Our approach demonstrates how to push current visualization workstations and modern visualization APIs to their limits to achieve interactive visualization of exa-scale time series data sets.
In diesem Artikel wird darüber berichtet, ob die Glaubwürdigkeit von Avataren als mögliches Modulationskriterium für die virtuelle Expositionstherapie von Agoraphobie in Frage kommt. Dafür werden mehrere Glaubwürdigkeitsstufen für Avatare, die hypothetisch einen Einfluss auf die virtuelle Expositionstherapie von Agoraphobie haben könnten sowie ein potentielles Expositionsszenario entwickelt. Die Arbeit kann innerhalb einer Studie einen signifikanten Einfluss der Glaubwürdigkeitsstufen auf Präsenz, Kopräsenz und Realismus aufzeigen.
Seit 2012 wird an der Hochschule Bonn-Rhein-Sieg die Studieneingangsphase im Qualitätspakt Lehre gefördert. Ein wesentliches Anliegen im Projekt „Pro-MINT-us“ ist die Einbeziehung der gesamten Hochschule, um keine isolierten Maßnahmen anzubieten, sondern die im Projekt entwickelten Lehrideen nachhaltig zu verankern.
An electronic display often has to present information from several sources. This contribution reports about an approach, in which programmable logic (FPGA) synchronises and combines several graphics inputs. The application area is computer graphics, especially rendering of large 3D models, which is a computing intensive task. Therefore, complex scenes are generated on parallel systems and merged to give the requested output image. So far, the transportation of intermediate results is often done by a local area network. However, as this can be a limiting factor, the new approach removes this bottleneck and combines the graphic signals with an FPGA.
Qualifikation für gute Lehre
(2010)
Eine von insgesamt sechs Arbeitsgruppen der Jahrestagung des HRK Bologna-Zentrums 2009 beschäftigte sich mit dem Themenbereich "Qualifikation für gute Lehre". Nach zwei Impulsvorträgen diskutierten die Teilnehmer, wie Hochschulangehörige noch stärker als bisher für die Lehre
qualifiziert werden können.
This paper introduces FaceHaptics, a novel haptic display based on a robot arm attached to a head-mounted virtual reality display. It provides localized, multi-directional and movable haptic cues in the form of wind, warmth, moving and single-point touch events and water spray to dedicated parts of the face not covered by the head-mounted display.The easily extensible system, however, can principally mount any type of compact haptic actuator or object. User study 1 showed that users appreciate the directional resolution of cues, and can judge wind direction well, especially when they move their head and wind direction is adjusted dynamically to compensate for head rotations. Study 2 showed that adding FaceHaptics cues to a VR walkthrough can significantly improve user experience, presence, and emotional responses.
Rendering techniques for design evaluation and review or for visualizing large volume data often use computationally expensive ray-based methods. Due to the number of pixels and the amount of data, these methods often do not achieve interactive frame rates. A view direction based rendering technique renders the users central field of view in high quality whereas the surrounding is rendered with a level of detail approach depending on the distance to the users central field of view thus giving the opportunity to increase rendering efficiency. We propose a prototype implementation and evaluation of a focus-based rendering technique based on a hybrid ray tracing/sparse voxel octree rendering approach.
In contrast to projection-based systems, large, high resolution multi-display systems offer a high pixel density on a large visualization area. This enables users to step up to the displays and see a small but highly detailed area. If the users move back a few steps they don't perceive details at pixel level but will instead get an overview of the whole visualization. Rendering techniques for design evaluation and review or for visualizing large volume data (e.g. Big Data applications) often use computationally expensive ray-based methods. Due to the number of pixels and the amount of data, these methods often do not achieve interactive frame rates.
A view direction based (VDB) rendering technique renders the user's central field of view in high quality whereas the surrounding is rendered with a level-of-detail approach depending on the distance to the user's central field of view. This approach mimics the physiology of the human eye and conserves the advantage of highly detailed information when standing close to the multi-display system as well as the general overview of the whole scene. In this paper we propose a prototype implementation and evaluation of a focus-based rendering technique based on a hybrid ray tracing/sparse voxel octree rendering approach.
In dieser Arbeit wird eine Methode zur Darstellung und Generierung von natürlich wirkendem Bewuchs auf besonders großen Arealen und unter Berücksichtigung ökologischer Faktoren vorgestellt. Die Generierung und Visualisierung von Bewuchs ist aufgrund der Komplexität biologischer Systeme und des Detailreichtums von Pflanzenmodellen ein herausforderndes Gebiet der Computergrafik und ermöglicht es, den Realismus von Landschaftsvisualisierungen erheblich zu steigern. Aufbauend auf [DMS06] wird bei Silva der Bewuchs so generiert, dass die zur Darstellung benötigten Wang-Kacheln und die mit ihnen assoziierten Teilverteilungen wiederverwendet werden können. Dazu wird ein Verfahren vorgestellt, um Poisson Disk Verteilungen mit variablen Radien auf nahtlosen Wang-Kachelmengen ohne rechenintensive globale Optimierung zu erzeugen. Durch die Einbeziehung von Nachbarschaften und frei konfigurierbaren Generierungspipelines können beliebige abiotische und biotische Faktoren bei der Bewuchsgenerierung berücksichtigt werden. Die durch Silva auf Wang-Kacheln erzeugten Pflanzenverteilungen ermöglichen, die darauf aufgebauten beschleunigenden Datenstrukturen bei der Visualisierung wieder zu verwenden. Durch Multi-Level Instancing und eine Schachtelung von Kd-Bäumen ist eine Visualisierung von großen bewachsenen Arealen mit geringen Renderzeiten und geringem Memoryfootprint von Hunderten Quadratkilometern Größe möglich.
A Low-Cost Based 6 DoF Head Tracker for Usability Application Studies in Virtual Environments
(2008)
We propose a high-performance GPU implementation of Ray Histogram Fusion (RHF), a denoising method for stochastic global illumination rendering. Based on the CPU implementation of the original algorithm, we present a naive GPU implementation and the necessary optimization steps. Eventually, we show that our optimizations increase the performance of RHF by two orders of magnitude when compared to the original CPU implementation and one order of magnitude compared to the naive GPU implementation. We show how the quality for identical rendering times relates to unfiltered path tracing and how much time is needed to achieve identical quality when compared to an unfiltered path traced result. Finally, we summarize our work and describe possible future applications and research based on this.
The work at hand outlines a recording setup for capturing hand and finger movements of musicians. The focus is on a series of baseline experiments on the detectability of coloured markers under different lighting conditions. With the goal of capturing and recording hand and finger movements of musicians in mind, requirements for such a system and existing approaches are analysed and compared. The results of the experiments and the analysis of related work show that the envisioned setup is suited for the expected scenario.
Large, high-resolution displays demonstrated their effectiveness in lab settings for cognitively demanding tasks in single user and collaborative scenarios. The effectiveness is mostly reached through inherent displays' properties - large display real estate and high resolution - that allow for visualization of complex datasets, and support of group work and embodied interaction. To raise users' efficiency, however, more sophisticated user support in the form of advanced user interfaces might be needed. For that we need profound understanding of how large, tiled displays impact users work and behavior. We need to extract behavioral patterns for different tasks and data types. This paper reports on study results of how users, while working collaboratively, process spatially fixed items on large, tiled displays. The results revealed a recurrent pattern showing that users prefer to process documents column wise rather than row wise or erratic.
Large, high-resolution displays are highly suitable for creation of digital environments for co-located collaborative task solving. Yet, placing multiple users in a shared environment may increase the risk of interferences, thus causing mental discomfort and decreasing efficiency of the team. To mitigate interferences coordination strategies and techniques were introduced. However, in a mixed-focus collaboration scenarios users switch now and again between loosely and tightly collaboration, therefore different coordination techniques might be required depending on the current collaboration state of team members. For that, systems have to be able to recognize collaboration states as well as transitions between them to ensure a proper adjustment of the coordination strategy. Previous studies on group behavior during collaboration in front of large displays investigated solely collaborative coupling states, not transitions between them though. To address this gap, we conducted a study with 12 participant dyads in front of a tiled display and let them solve two tasks in two different conditions (focus and overview). We looked into group dynamics and categorized transitions by means of changes in proximity, verbal communication, visual attention, visual interface, and gestures. The findings can be valuable for user interface design and development of group behavior models.
Supported by their large size and high resolution, display walls suit well for different collaboration types. However, in order to foster instead of impede collaboration processes, interaction techniques need to be carefully designed, taking into regard the possibilities and limitations of the display size, and their effects on human perception and performance. In this paper we investigate the impact of visual distractors (which, for instance, might be caused by other collaborators' input) in peripheral vision on short-term memory and attention. The distractors occur frequently when multiple users collaborate in large wall display systems and may draw attention away from the main task, as such potentially affecting performance and cognitive load. Yet, the effect of these distractors is hardly understood. Gaining a better understanding thus may provide valuable input for designing more effective user interfaces. In this article, we report on two interrelated studies that investigated the effect of distractors. Depending on when the distractor is inserted in the task performance sequence, as well as the location of the distractor, user performance can be disturbed: we will show that distractors may not affect short term memory, but do have an effect on attention. We will closely look into the effects, and identify future directions to design more effective interfaces.
This paper presents groupware to study group behavior while conducting a creative task on large, high-resolution displays. Moreover, we present the results of a between-subjects study. In the study, 12 groups with two participants each prototyped a 2D level on a 7m x 2.5m large, high-resolution display using tablet-PCs for interaction. Six groups underwent a condition where group members had equal roles and interaction possibilities. Another six groups worked in a condition where group members had different roles: level designer and 2D artist. The results revealed that in the different roles condition, the participants worked significantly more tightly and created more assets. We could also detect some shortcomings for that configuration. We discuss the gained insights regarding system configuration, groupware interfaces, and groups behavior.
Effects of Workspace Awareness and Territoriality in Environments with Large, Shared Displays
(2016)
Synchronous cooperative work of multiple collaborators in large, high-resolution display systems comprises such psychological phenomena like workspace awareness and human territoriality. The phenomena and interplay between them can cause a significant impact on human-human and human-environment interaction. In a non-digital environment humans rely on their own physical abilities, utilities, and social protocols to control those phenomena (e.g. close eyes, or use earplugs to reduce workspace awareness; rotate oneself towards collaborators to increase workspace awareness). Digital environments, on the other hand, provide us with a possibility to ease, automate, and unify control processes, thus taking off that burden from users. Yet, we have to understand first, what effects workspace awareness and territoriality have within a collaborative environment. The aim of this doctoral thesis is to investigate effects of workspace awareness and territoriality on users and interaction processes in mixed-focus scenarios of various collaborative settings.
Gone But Not Forgotten: Evaluating Performance and Scalability of Real-Time Mesoscopic Agents
(2020)
Simulating eye movements for virtual humans or avatars can improve social experiences in virtual reality (VR) games, especially when wearing head mounted displays. While other researchers have already demonstrated the importance of simulating meaningful eye movements, we compare three gaze models with different levels of fidelity regarding realism: (1) a base model with static fixation and saccadic movements, (2) a proposed simulation model that extends the saccadic model with gaze shifts based on a neural network, and (3) a user's real eye movements recorded by a proprietary eye tracker. Our between-groups design study with 42 subjects evaluates impact of eye movements on social VR user experience regarding perceived quality of communication and presence. The tasks include free conversation and two guessing games in a co-located setting. Results indicate that a high quality of communication in co-located VR can be achieved without using extended gaze behavior models besides saccadic simulation. Users might have to gain more experience with VR technology before being able to notice subtle details in gaze animation. In the future, remote VR collaboration involving different tasks requires further investigation.
Traffic simulations are typically concerned with modeling human behavior as closely as possible to create realistic results. In conventional traffic simulations used for road planning or traffic jam prediction only the overall behavior of an entire system is of interest. In virtual environments, like digital games, simulated traffic participants are merely a backdrop to the player’s experience and only need to be “sufficiently realistic”. Additionally, restricted computational resources, typical for virtual environment applications, usually limit the complexity of simulated behavior in this field. More importantly, two integral aspects of real-world traffic are not considered in current traffic simulations from both fields: misbehavior and risk taking of traffic participants. However, for certain applications like the FIVIS bicycle simulator, these aspects are essential.
Populating virtual worlds with intelligent agents can drastically improve a user's sense of presence. Applying these worlds to virtual training, simulations, or (serious) games, often requires multiple agents to be simulated in real time. The process of generating believable agent behavior starts with providing a plausible perception and attention process that is both efficient and controllable. We describe a conceptual framework for synthetic perception that specifically considers the mentioned requirements: plausibility, real-time performance, and controllability. A sample implementation will focus on sensing, attention, and memory to demonstrate the framework's capabilities in a real-time game engine scenario. A combination of dynamic geometric sensing and false coloring with static saliency information is provided to exemplify the collection of environmental stimuli. The subsequent attention process handles both bottom-up processing and task-oriented, top-down factors. Behavioral results can be influenced by controlling memory and attention The example case is demonstrated and discussed alongside future extensions.