13 Zentrale Universitätseinrichtungen
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/14
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Item Open Access Datamator : an authoring tool for creating datamations via data query decomposition(2023) Guo, Yi; Cao, Nan; Cai, Ligan; Wu, Yanqiu; Weiskopf, Daniel; Shi, Danqing; Chen, QingDatamation is designed to animate an analysis pipeline step by step, serving as an intuitive and efficient method for interpreting data analysis outcomes and facilitating easy sharing with others. However, the creation of a datamation is a difficult task that demands expertise in diverse skills. To simplify this task, we introduce Datamator, a language-oriented authoring tool developed to support datamation generation. In this system, we develop a data query analyzer that enables users to generate an initial datamation effortlessly by inputting a data question in natural language. Then, the datamation is displayed in an interactive editor that affords users the ability to both edit the analysis progression and delve into the specifics of each step undertaken. Notably, the Datamator incorporates a novel calibration network that is able to optimize the outputs of the query decomposition network using a small amount of user feedback. To demonstrate the effectiveness of Datamator, we conduct a series of evaluations including performance validation, a controlled user study, and expert interviews.Item Open Access Augmenting sports storytelling for people with visual impairments(2025) Koch, PhillipSports storytelling combines data, visuals, and narratives to create an emotional connection with fans. Likewise, people with visual impairments face unique challenges while attending sports events. This thesis proposes a visual approach to assistive technologies, aiming to assist sports spectators with visual impairment to face these challenges. To understand these needs and challenges, I conducted interviews with two football fans who are visually impaired. The findings of the interviews revealed the need for general visual cues to facilitate simple tasks and emphasise detailed information. From these findings, I developed a set of visual cues to highlight main aspects of football matches, including cues for the ball, players, and more general tools like a magnifying glass. The cues were tested in a football scenario during a co-design user study with three sports fans who are visually impaired. The results of the user study suggest that visual cues show promising results in aiding people with visual impairments in the role of sports spectators. This thesis highlights the distinct effectiveness of general cues, situation-dependent cues, detailed cues, and the importance of customisation of these cues. This contributes to the scope of accessible research and reader-driven narrative during sports events.Item Open Access Touching data with PropellerHand(2022) Achberger, Alexander; Heyen, Frank; Vidackovic, Kresimir; Sedlmair, MichaelImmersive analytics often takes place in virtual environments which promise the users immersion. To fulfill this promise, sensory feedback, such as haptics, is an important component, which is however not well supported yet. Existing haptic devices are often expensive, stationary, or occupy the user’s hand, preventing them from grasping objects or using a controller. We propose PropellerHand, an ungrounded hand-mounted haptic device with two rotatable propellers, that allows exerting forces on the hand without obstructing hand use. PropellerHand is able to simulate feedback such as weight and torque by generating thrust up to 11 N in 2-DOF and a torque of 1.87 Nm in 2-DOF. Its design builds on our experience from quantitative and qualitative experiments with different form factors and parts. We evaluated our prototype through a qualitative user study in various VR scenarios that required participants to manipulate virtual objects in different ways, while changing between torques and directional forces. Results show that PropellerHand improves users’ immersion in virtual reality. Additionally, we conducted a second user study in the field of immersive visualization to investigate the potential benefits of PropellerHand there.Item Open Access Code execution reports: visually augmented summaries of executed source code fragments(2016) Siddiqui, Hafiz AmmarUnderstanding a fragment of code is important for developers as it enables them to optimize, debug and extend it. Developers adopt different procedures for understanding a piece of code, which involves going through the source code, documentation, and profilers results. Various code comprehension techniques have suggested code summarization approaches, which generates the intended behavior of code in natural language text. In this thesis, we present an approach to summarize the actual behavior of a method during its execution. For this purpose, we create a framework that facilitates the generation of interactive and web-based natural language reports with small embedded word-size visualizations. Then, we develop a tool that profiles a method for runtime behavior, and then it processes the information. The tool uses our framework to generate a visually augmented natural language summary report that explains the behavior of the code. In the end, we conduct a small user study to evaluate the quality of our code execution reports.Item Open Access Point cloud and particle data compression techniques(2023) Ravi, NiranjanThe contemporary need for heightened processing speed and storage capacity has necessitated the implementation of data compression in various applications. This study encompasses a diverse array of applications, varying in scale, that need the implementation of efficient compression techniques. At present, there is no universally preferred compression technique that can outperform others across all data types. This is due to the fact that certain compression methods are more effective in compressing specific applications than others. Point cloud data finds widespread usage in diverse domains such as computer vision, robotics, and virtual as well as augmented reality. The dense nature of point cloud data presents difficulties with respect to storage, transmission, and computation. In a similar way, particle data usually contains significant amounts of particles that have been produced through simulations, experiments, or observations. The magnitude of particle data and the computational resources necessary to handle and examine such datasets can pose a formidable obstacle. To date, there has been no direct comparative analysis of compression methodologies applied to particle data and point cloud data. This study represents the initial attempt to compare these two distinct categories. The primary objective of this study is to test different compression techniques belonging to the particle and point cloud worlds and establish a standardized metric for evaluating the effectiveness of those compression methodologies. An integrated tool has been developed in this work that incorporates various compression techniques to evaluate the appropriateness of each technique for particle data and point cloud data. The assessment of compression techniques involves the consideration of particle error metrics and point cloud error metrics. Evidence from experiments in this work demonstrates that particle compressors exhibit superior performance across both tested data categories, while point cloud compressors demonstrate superior performance solely for point cloud data. Also, it reveals that the particle error metrics exhibit stringent boundaries, which are deemed necessary for the type of data they are intended to analyze. In contrast, the point cloud error metrics display more relaxed boundaries.Item Open Access Comparative visualization across physical and parameter space(2022) Zeyfang, AdrianWe designed and developed an interactive visualization approach for exploring and comparing image sequences in the context of porous media research. Our tool facilitates the visual analysis of two-dimensional image sequence datasets captured during fluid displacement experiments in a porous micromodel. The images are aggregated into a single graph-based representation, allowing for an experiment to be visualized across its entire temporal domain. This graph is generated from the viscous flow patterns of the invading fluid, reducing the need for manual image masking and clean-up steps. The Node-Link representation of the graph is superimposed onto the raw images, creating a composite spatio-temporal view of the dataset. We demonstrate the functionality of our implementation by evaluating its output and performance on a collection of related datasets. We found that separate experiments in the same porous medium yield topologically different, yet visually similar flow graphs with comparable node positions.Item Open Access Visual analytics of big data from distributed systems(2017) Kutzleb, AndréDistributed Systems are challenging to debug because the temporal order of events and distributed states are hard to track. The high complexity of distributed systems make fully automatic reasoning difficult to apply. Domain experts are often required to reason about the behavior of a system based on log files from various sources. This situation presents a good opportunity for visual analytics. Data from multiple sources can be preprocessed and visualized, and then domain experts can conduct exploratory analysis to accelerate the identification of issues. The goal of this master thesis was to create such a visual analytics tool to help domain experts explore data collected from distributed systems more efficiently and assist in identifying bugs and anomalies. The system was used by domain experts and helped to identify issues in a distributed system, showing that visual analytics can be a useful tool to assist domain experts in their daily work.Item Open Access Visualization techniques for parallel coordinates(2013) Heinrich, Julian; Weiskopf, Daniel (Prof. Dr.)Visualization plays a key role in knowledge discovery, visual data exploration, and visual analytics. Static images are an effective tool for visual communication, summarization, and pattern extraction in large and complex datasets. Only together with human-computer-interaction techniques, visual interfaces enable an analyst to explore large information spaces and to drive the whole analytical reasoning process. Scatterplots and parallel coordinates are well-recognized visualization techniques that are commonly employed for statistics (both explorative and descriptive) and data-mining, but are also gaining importance for scientific visualization. While scatterplots are restricted to the display of at most three dimensions due to the orthogonal layout of coordinate axes, a parallel arrangement allows for the visualization of multiple attributes of a dataset. Although both techniques rely on projections of higher-dimensional geometry and are related by a point–line duality, parallel coordinates enjoy great popularity for the visualization and analysis of multivariate data. Despite their popularity, parallel coordinates are subject to a number of limitations that remain to be solved. For large datasets, the potentially high amount of overlapping lines may hinder the observer from visually extracting meaningful patterns. Encoding observations with polylines make it difficult to follow lines over all dimensions, as they lose visual continuation across the axes. Clusters cannot be represented by the geometry of lines, and the order of axes has a high impact on the patterns exhibited by parallel coordinates. This thesis presents visualization techniques for parallel coordinates that address these limitations. As a foundation, an extensive review of the state of the art of parallel coordinates will be given. Based on the point–line duality, the existing model of continuous scatterplots is adapted to parallel coordinates for the visualization of data defined on continuous domains. To speed up computation and obtain interactive frame rates, a scalable and progressive rendering algorithm is introduced that further allows for arbitrary reconstruction and interpolation schemes. A curve-bundling model for parallel coordinates is evaluated with a user study showing that bundling is effective for cluster visualization based on geometric cues while being equally capable of revealing correlations between neighboring axes. To address the axis-order problem, a graph-based approach is presented that allows for the visualization of all pairwise relations in a matrix layout without redundancy. Finally, the use of parallel coordinates is demonstrated for real datasets from computational fluid dynamics, motion capturing, bioinformatics, and systems biology.Item Open Access 3D visualization of multivariate data(2012) Sanftmann, Harald; Weiskopf, Daniel (Prof. Dr.)Nowadays large amounts of data are organized in tables, especially in relational databases where the rows store the data items to which multiple attributes are stored in the columns. Information stored this way, having multiple (more than two or three) attributes, can be treated as multivariate data. Therefore, visualization methods for multivariate data have a large application area and high potential utility. This thesis focuses on the application of 3D scatter plots for the visualization of multivariate data. When dealing with 3D, spatial perception needs to be exploited, by effectively using depth cues to convey spatial information to the user. To improve the presentation of individual 3D scatter plots, a technique is presented that applies illumination to them, thus using the shape-from-shading depth cue. To enable the analysis not only of 3D but of multivariate data, a novel technique is introduced that allows the navigation between 3D scatter plots. Inspecting the large number of 3D scatter plots that can be projected from a multivariate data set is very time consuming. The analysis of multivariate data can benefit from automatic machine learning approaches. A presented method uses decision trees to increase the speed a user can gain an understanding of the multivariate data at no extra cost. Stereopsis can also support the display of 3D scatter plots. Here an improved anaglyph rendering technique is presented, significantly reducing ghosting artifacts. The technique is not only applicable for information visualization, but for general rendering or to present stereoscopic image data. Some information visualization algorithms require high computation time. Many of these algorithms can be parallelized to run interactively. A framework that supports the parallelization on shared and distributed memory systems is presented.Item Open Access Augmented visualization guidance for wire placement in timber fabrication(2021) Zhu, MarcoAugmented reality has become a broad area over time, which opens up many opportunities, also for industry. Nevertheless, digital solutions have not yet been used for some industrial applications. We focus on the use case “wire placement in timber fabrication”. The task here is to place and fix a cable along a certain route on a timber panel. However, there are several important factors and risks to consider that could cause the task to fail. Usability and efficiency play an essential role in optimally supporting use cases like this. Furthermore, we hope to make the task of this special industrial use case easier for workers by using augmented reality. For such an optimization, the design of a suitable visualization as part of the augmented reality system is indispensable. We constructed possible virtual representations for this use case and developed different suitable prototypes. Based on a user study, we compared the visualizations of these prototypes, evaluated their efficiency and user experience by measuring the workload, usability, task completion time, and determining error rates. By analyzing the developed visualization prototypes, a certain prototype proved to be optimal. With this, the route of the cable is shown as a path on the timber plate and displayed in color. The efficiency differences between this prototype and the other prototypes, supported by augmented reality, are not severe. The use of the augmented reality system turned out to be an essential enrichment. Compared to an equivalent system that is not supported by augmented reality, the developed augmented reality systems showed clear advantages. The suitability of this prototype has been checked and proven through a dry run. The task of the use case could be carried out successfully while the important factors and risks were also considered. The final fabrication has yet to be carried out.