Eva Mayr

Hierarchical Temporal Patterns and Interactive Aggregated Views for Pixel-Based Visualizations

Many real-world problems involve time-oriented data. Time data is different from other kinds of data--explicitly harnessing the structures of time in visualizations can guide and support users’ visual analysis processes. State-of-the-art visualizations hardly take advantage of the structures of time to aid users in understanding and exploring the data. To bring more flexibility to the analysis process, we have developed interactive visual methods incorporating the structures of time within a pixel-based visualization called GROOVE (granular overview overlay). GROOVE uses different techniques to visualize time-oriented data by overlaying several time granularities in one visualization and provides interactive operators, which utilize the structures of time in different ways to capture and explore time-oriented data.

The User Puzzle—Explaining the Interaction with Visual Analytics Systems

Visual analytics emphasizes the interplay between visualization, analytical procedures performed by computers and human perceptual and cognitive activities. Human reasoning is an important element in this context. There are several theories in psychology and HCI explaining open-ended and exploratory reasoning. Five of these theories (sensemaking theories, gestalt theories, distributed cognition, graph comprehension theories and skill-rule-knowledge models) are described in this paper. We discuss their relevance for visual analytics. In order to do this more systematically, we developed a schema of categories relevant for visual analytics research and evaluation. All these theories have strengths but also weaknesses in explaining interaction with visual analytics systems. A possibility to overcome the weaknesses would be to combine two or more of these theories.

A User-Centered Design Approach to Self-Service Ticket Vending Machines

Since their introduction, self-service ticket vending machines (TVMs) have become an increasingly important distribution channel in the public transport sector, progressively replacing the traditional ticket counter. In a public transport setting, where ticket counter closures have left different groups of people dependent on TVM to meet their mobility needs, a single, effective system is required. Research questions: (1) Which barriers do currently hinder the usage of TVM? (2) Which requirements should a barrier-free TVM fulfill? (3) How can we design a new self-service TVM for a nationwide public railway company? (4) How can we ensure that the usability and user experience (UX) is high for all users, especially for those with low levels of technological affinity? Situating the case: Most other studies on the use and usability of TVMs were conducted as post-hoc evaluations. In contrast, our case study presents a user-centered design (UCD) approach that takes the needs of the different target groups into account throughout the whole development process. Theories and concepts that guided the case included UCD, which involves alternating test and evaluation loops that actively involve users to create a usable product and UX, which describes the quality of the experience a person has when interacting with a specific computer system using a specific interaction technique. Methodology: More than 250 participants were involved in focus groups, observations, interviews, and experiments from the very first stages of development. Interface designs were presented to the future end users to obtain their feedback, with the results fed back into the design process. About the case: A prototype for a novel generation of TVM was developed in three phases: First, the context of use was analyzed. In the second phase, we conducted a requirements analysis. Third, different hardware and software interaction designs were iteratively tested and evaluated. The resulting prototype met the requirements of most user groups, though further adjustments are necessary. Conclusions: The UCD approach proved to be a valuable framework for the development and design of self-service systems.

Many roads lead to Rome: mapping users' problem-solving strategies

There is more than one path to a solution, especially when it comes to ill-defined problems like complex, real-world tasks. Until now, the evaluation of information visualizations has often been restricted simply to a measuring of outcomes (time and error) or insights into the data set. A more detailed look into the processes that facilitate or hinder task completion is provided by analysing user problem-solving strategies. The study presented in this paper illustrates how such processes can be assessed and how the resulting knowledge can be used in participatory design to improve a visual analytics tool. For users to be equipped with a problem-solving scaffold, the tools used should allow them to choose their own path to the solution – their own route to Rome. We also discuss how the evaluation of problem-solving strategies can shed more light on the ‘exploratory minds’ of users.

Visualizations at First Sight: Do Insights Require Training?

Understanding novel visualizations can be a challenge even forexperienced users. During iterative usability engineering phases inthe DisCō project, visualizations of time-oriented data areexplored by domain experts and non-experts. The aim of our study isto analyze the generation of knowledge and understanding by meansof visualizations without previous user training. Focusing onapplicability in various business domains for personnel planningand time scheduling, we tested mockups of visualizations with amethod based on user-reported insights. Results show almostidentical behavior of domain experts and non-experts whengenerating insights into the data from scratch. In the course ofworking with a visualization, an interchange of insights into thevisualization and insights into the data was found.

Cultural Heritage Cube. A Conceptual Framework for Visual Exhibition Exploration

Cultural heritage exhibitions commonly have to arrange a high amount of diverse artefacts and associated information in architecturally complex facilities. This constellation issues challenges to both: exhibition designers who have to find ways to deal with spatial restrictions and visitors who often experience cognitive overload and museum fatigue due to the high amount of information available. Against this background, the article is focusing on the question, how information visualization can serve as advance organizer, to make the organizing principles of cultural heritage exhibitions (like common topics, themes, geographical or temporal origin) transparent to the visitors. For this purpose, we extend the visualization method of time geography to an interactive visualization framework of time topography, which can support the interactive exploration of conceptual and physical cultural heritage exhibition spaces in parallel.

Is your user hunting or gathering insights?: identifying insight drivers across domains

In recent years, using the number of insights to benchmark visual analytics tools has become a prominent method in the Infovis community. The insight methodology has become a frequently used instrument to measure the performance of tools that are developed for highly specialized purposes for highly specialized domain-experts. But some tools have a wider target group of experts with knowledge in different domains. The utility of the insight-method for other expert user groups without specific domain knowledge has been addressed to a far lesser extent. In a case study we give an illustration of how and where insights from experts with and without domain knowledge differ, and how these findings might enrich the evaluation of visualization tools designed for usage across different domains.

E-Inclusion in Public Transport: The Role of Self-efficacy

Many subgroups in todays society are not skilled in using novel technologies. Even everyday technologies pose a barrier to technically non-skilled people and --- if they fail to use them --- exclude them from important parts of daily life. In this paper we discuss the relevance of self-efficacy for the use of one specific kind of everyday technology: the ticket vending machine. Results from observations and interviews within the research project InnoMat are presented to answer the question how self-efficacy influences the ticket buying behavior and show that this motivational factor leads to an active avoidance of ticket machines. Negative experiences seem to be one of the strongest influences, which indicate that the group of technically non-skilled users should be given special attention when developing a new generation of ticket vending machines.

Once upon a Spacetime: Visual Storytelling in Cognitive and Geotemporal Information Spaces

Stories are an essential mode, not only of human communication—but also of thinking. This paper reflects on the internalization of stories from a cognitive perspective and outlines a visualization framework for supporting the analysis of narrative geotemporal data. We discuss the strengths and limitations of standard techniques for representing spatiotemporal data (coordinated views, animation or slideshow, layer superimposition, juxtaposition, and space-time cube representation) and think about their effects on mental representations of a story. Many current visualization systems offer multiple views and allow the user to investigate different aspects of a story. From a cognitive point of view, it is important to assist users in reconnecting these multiple perspectives into a coherent picture—e.g., by utilizing coherence techniques like seamless transitions. A case study involving visualizing biographical narratives illustrates how the design of advanced visualization systems can be cognitively and conceptually grounded to support the construction of an integrated internal representation.

Looking at the Representations in our Mind: Measuring Mental Models of Information Visualizations

Users of information visualization systems build up internal representations of the displayed information and the system --mental models -- and constantly update them during interaction with the system. Though this theoretical approach was postulated as promising for information visualization, measures for empirical studies are missing. In this paper, we present different measures and evaluation procedures that have been developed for the assessment of mental models in other domains and discuss their suitability for the evaluation of internal and external representations in information visualization.