EuroVA: International Workshop on Visual Analytics
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Item EuroVa 2021: Frontmatter(The Eurographics Association, 2021) Bernard, Jürgen; Vrotsou, Katerina; Vrotsou, Katerina and Bernard, JürgenItem EuroVa 2022: Frontmatter(The Eurographics Association, 2022) Bernard, Jürgen; Angelini, Marco; Bernard, Jürgen; Angelini, MarcoItem Human-Based and Automatic Feature Ideation for Time Series Data: A Comparative Study(The Eurographics Association, 2023) Schmidt, Johanna; Piringer, Harald; Mühlbacher, Thomas; Bernard, Jürgen; Angelini, Marco; El-Assady, MennatallahFeature ideation is a crucial early step in the feature extraction process, where new features are extracted from raw data. For phenomena existing in time series data, this often includes the ideation of statistical parameters, representations of trends and periodicity, or other geometrical and shape-based characteristics. The strengths of automatic feature ideation methods are their generalizability, applicability, and robustness across cases, whereas human-based feature ideation is most useful in uncharted real-world applications, where incorporating domain knowledge is key. Naturally, both types of methods have proven their right to exist. The motivation for this work is our observation that for time series data, surprisingly few human-based feature ideation approaches exist. In this work, we discuss requirements for human-based feature ideation for VA applications and outline a set of characteristics to assess the goodness of feature sets. Ultimately, we present the results of a comparative study of humanbased and automated feature ideation methods, for time series data in a real-world Industry 4.0 setting. One of our results and discussion items is a call to arms for more human-based feature ideation approaches.Item Interactive Visual Explanation of Incremental Data Labeling(The Eurographics Association, 2022) Beckmann, Raphael; Blaga, Cristian; El-Assady, Mennatallah; Zeppelzauer, Matthias; Bernard, Jürgen; Bernard, Jürgen; Angelini, MarcoWe present a visual analytics approach for the in-depth analysis and explanation of incremental machine learning processes that are based on data labeling. Our approach offers multiple perspectives to explain the process, i.e., data characteristics, label distribution, class characteristics, and classifier characteristics. Additionally, we introduce metrics from which we derive novel aggregated analytic views that enable the analysis of the process over time. We demonstrate the capabilities of our approach in a case study and thereby demonstrate how our approach improves the transparency of the iterative learning process.Item Learning and Teaching in Co-Adaptive Guidance for Mixed-Initiative Visual Analytics(The Eurographics Association, 2020) Sperrle, Fabian; Jeitler, Astrik; Bernard, Jürgen; Keim, Daniel A.; El-Assady, Mennatallah; Turkay, Cagatay and Vrotsou, KaterinaGuidance processes in visual analytics applications often lack adaptivity. In this position paper, we contribute the concept of co-adaptive guidance, building on the principles of initiation and adaptation. We argue that both the user and the system adapt their data-, task- and user/system-models over time. Based on these principles, we propose reasoning about the guidance design space through introducing the concepts of learning and teaching that complement the existing dimension of implicit and explicit guidance, thus, deriving the four guidance dynamics user-teaching, system-teaching, user-learning, and system-learning. Finally, we classify current guidance approaches according to the dynamics, demonstrating their applicability to co-adaptive guidance.Item LFPeers: Temporal Similarity Search in Covid-19 Data(The Eurographics Association, 2021) Burmeister, Jan; Bernard, Jürgen; Kohlhammer, Jörn; Vrotsou, Katerina and Bernard, JürgenWhile there is a wide variety of visualizations and dashboards to help understand the data of the Covid-19 pandemic, hardly any of these support important analytical tasks, especially of temporal attributes. In this paper, we introduce a general concept for the analysis of temporal and multimodal data and the system LFPeers that applies this concept to the analysis of countries in a Covid-19 dataset. Our concept divides the analysis in two phases: a search phase to find the most similar objects to a target object before a time point t0, and an exploration phase to analyze this subset of objects after t0. LFPeers targets epidemiologists and the public who want to learn from the Covid-19 pandemic and distinguish successful and ineffective measures.Item Quantifying Uncertainty in Multivariate Time Series Pre-Processing(The Eurographics Association, 2019) Bors, Christian; Bernard, Jürgen; Bögl, Markus; Gschwandtner, Theresia; Kohlhammer, Jörn; Miksch, Silvia; Landesberger, Tatiana von and Turkay, CagatayIn multivariate time series analysis, pre-processing is integral for enabling analysis, but inevitably introduces uncertainty into the data. Enabling the assessment of the uncertainty and allowing uncertainty-aware analysis, the uncertainty needs to be quantified initially. We address this challenge by formalizing the quantification of uncertainty for multivariate time series preprocessing. To tackle the large design space, we elaborate key considerations for quantifying and aggregating uncertainty. We provide an example how the quantified uncertainty is used in a multivariate time series pre-processing application to assess the effectiveness of pre-processing steps and adjust the pipeline to minimize the introduction of uncertainty.Item RankASco: A Visual Analytics Approach to Leverage Attribute-Based User Preferences for Item Rankings(The Eurographics Association, 2022) Schmid, Jenny; Cibulski, Lena; Hazwani, Ibrahim Al; Bernard, Jürgen; Bernard, Jürgen; Angelini, MarcoItem rankings are useful when a decision needs to be made, especially if there are multiple attributes to be considered. However, existing tools either do not support both categorical and numerical attributes, require programming expertise for expressing preferences on attributes, do not offer instant feedback, or lack flexibility in expressing various types of user preferences. In this work, we present RankASco: a human-centered visual analytics approach that supports the interactive and visual creation of rankings. RankASco leverages a series of visual interfaces, enabling broad user groups to a) select attributes of interest, b) express preferences on attribute scorings based on different mental models, and c) analyze and refine item ranking results.Item SepEx: Visual Analysis of Class Separation Measures(The Eurographics Association, 2020) Bernard, Jürgen; Hutter, Marco; Zeppelzauer, Matthias; Sedlmair, Michael; Munzner, Tamara; Turkay, Cagatay and Vrotsou, KaterinaClass separation is an important concept in machine learning and visual analytics. However, the comparison of class separation for datasets with varying dimensionality is non-trivial, given a) the various possible structural characteristics of datasets and b) the plethora of separation measures that exist. Building upon recent findings in visualization research about the qualitative and quantitative evaluation of class separation for 2D dimensionally reduced data using scatterplots, this research addresses the visual analysis of class separation measures for high-dimensional data. We present SepEx, an interactive visualization approach for the assessment and comparison of class separation measures for multiple datasets. SepEx supports analysts with the comparison of multiple separation measures over many high-dimensional datasets, the effect of dimensionality reduction on measure outputs by supporting nD to 2D comparison, and the comparison of the effect of different dimensionality reduction methods on measure outputs. We demonstrate SepEx in a scenario on 100 two-class 5D datasets with a linearly increasing amount of separation between the classes, illustrating both similarities and nonlinearities across 11 measures.Item A Taxonomy of Attribute Scoring Functions(The Eurographics Association, 2021) Schmid, Jenny; Bernard, Jürgen; Vrotsou, Katerina and Bernard, JürgenShifting the analysis from items to the granularity of attributes is a promising approach to address complex decision-making problems. In this work, we study attribute scoring functions (ASFs), which transform values from data attributes to numerical scores. As the output of ASFs for different attributes is always comparable and scores carry user preferences, ASFs are particularly useful for analysis goals such as multi-attribute ranking, multi-criteria optimization, or similarity modeling. However, non-programmers cannot yet fully leverage their individual preferences on attribute values, as visual analytics (VA) support for the creation of ASFs is still in its infancy, and guidelines for the creation of ASFs are missing almost entirely. We present a taxonomy of eight types of ASFs and an overview of tools for the creation of ASFs as a result of an extensive literature review. Both the taxonomy and the tools overview have descriptive power, as they represent and combine non-visual math and statistics perspectives with the VA perspective. We underpin the usefulness of VA support for broader user groups in real-world cases for all eight types of ASFs, unveil missing VA support for the ASF creation, and discuss the integration of ASF in VA workflows.Item Visual Analysis of Degree-of-Interest Functions to Support Selection Strategies for Instance Labeling(The Eurographics Association, 2019) Bernard, Jürgen; Hutter, Marco; Ritter, Christian; Lehmann, Markus; Sedlmair, Michael; Zeppelzauer, Matthias; Landesberger, Tatiana von and Turkay, CagatayManually labeling data sets is a time-consuming and expensive task that can be accelerated by interactive machine learning and visual analytics approaches. At the core of these approaches are strategies for the selection of candidate instances to label. We introduce degree-of-interest (DOI) functions as atomic building blocks to formalize candidate selection strategies. We introduce a taxonomy of DOI functions and an approach for the visual analysis of DOI functions, which provide novel complementary views on labeling strategies and DOIs, support their in-depth analysis and facilitate their interpretation. Our method shall support the generation of novel and better explanation of existing labeling strategies in future.Item Why am I reading this? Explaining Personalized News Recommender Systems(The Eurographics Association, 2023) Arnórsson, Sverrir; Abeillon, Florian; Al-Hazwani, Ibrahim; Bernard, Jürgen; Hauptmann, Hanna; El-Assady, Mennatallah; Angelini, Marco; El-Assady, MennatallahSocial media and online platforms significantly impact what millions of people get exposed to daily, mainly through recommended content. Hence, recommendation processes have to benefit individuals and society. With this in mind, we present the visual workspace NewsRecXplain, with the goals of (1) explaining and raising awareness about recommender systems, (2) enabling individuals to control and customize news recommendations, and (3) empowering users to contextualize their news recommendations to escape from their filter bubbles. This visual workspace achieves these goals by allowing users to configure their own individualized recommender system, whose news recommendations can then be explained within the workspace by way of embeddings and statistics on content diversity.