Evaluating the Effect of Timeline Shape on Visualization Task Performance

Timelines are commonly represented on a horizontal line, which is not necessarily the most effective way to visualize temporal event sequences. However, few experiments have evaluated how timeline shape influences task performance. We present the design and results of a controlled experiment run on Amazon Mechanical Turk (n=192) in which we evaluate how timeline shape affects task completion time, correctness, and user preference. We tested 12 combinations of 4 shapes -- horizontal line, vertical line, circle, and spiral -- and 3 data types -- recurrent, non-recurrent, and mixed event sequences. We found good evidence that timeline shape meaningfully affects user task completion time but not correctness and that users have a strong shape preference. Building on our results, we present design guidelines for creating effective timeline visualizations based on user task and data types. A free copy of this paper, the evaluation stimuli and data, and code are available at https://osf.io/qr5yu/Comment: 12 pages, 5 figure

Tabletop tangible maps and diagrams for visually impaired users

En dépit de leur omniprésence et de leur rôle essentiel dans nos vies professionnelles et personnelles, les représentations graphiques, qu'elles soient numériques ou sur papier, ne sont pas accessibles aux personnes déficientes visuelles car elles ne fournissent pas d'informations tactiles. Par ailleurs, les inégalités d'accès à ces représentations ne cessent de s'accroître ; grâce au développement de représentations graphiques dynamiques et disponibles en ligne, les personnes voyantes peuvent non seulement accéder à de grandes quantités de données, mais aussi interagir avec ces données par le biais de fonctionnalités avancées (changement d'échelle, sélection des données à afficher, etc.). En revanche, pour les personnes déficientes visuelles, les techniques actuellement utilisées pour rendre accessibles les cartes et les diagrammes nécessitent l'intervention de spécialistes et ne permettent pas la création de représentations interactives. Cependant, les récentes avancées dans le domaine de l'adaptation automatique de contenus laissent entrevoir, dans les prochaines années, une augmentation de la quantité de contenus adaptés. Cette augmentation doit aller de pair avec le développement de dispositifs utilisables et abordables en mesure de supporter l'affichage de représentations interactives et rapidement modifiables, tout en étant accessibles aux personnes déficientes visuelles. Certains prototypes de recherche s'appuient sur une représentation numérique seulement : ils peuvent être instantanément modifiés mais ne fournissent que très peu de retour tactile, ce qui rend leur exploration complexe d'un point de vue cognitif et impose de fortes contraintes sur le contenu. D'autres prototypes s'appuient sur une représentation numérique et physique : bien qu'ils puissent être explorés tactilement, ce qui est un réel avantage, ils nécessitent un support tactile qui empêche toute modification rapide. Quant aux dispositifs similaires à des tablettes Braille, mais avec des milliers de picots, leur coût est prohibitif. L'objectif de cette thèse est de pallier les limitations de ces approches en étudiant comment développer des cartes et diagrammes interactifs physiques, modifiables et abordables. Pour cela, nous nous appuyons sur un type d'interface qui a rarement été étudié pour des utilisateurs déficients visuels : les interfaces tangibles, et plus particulièrement les interfaces tangibles sur table. Dans ces interfaces, des objets physiques représentent des informations numériques et peuvent être manipulés par l'utilisateur pour interagir avec le système, ou par le système lui-même pour refléter un changement du modèle numérique - on parle alors d'interfaces tangibles sur tables animées, ou actuated. Grâce à la conception, au développement et à l'évaluation de trois interfaces tangibles sur table (les Tangible Reels, la Tangible Box et BotMap), nous proposons un ensemble de solutions techniques répondant aux spécificités des interfaces tangibles pour des personnes déficientes visuelles, ainsi que de nouvelles techniques d'interaction non-visuelles, notamment pour la reconstruction d'une carte ou d'un diagramme et l'exploration de cartes de type " Pan & Zoom ". D'un point de vue théorique, nous proposons aussi une nouvelle classification pour les dispositifs interactifs accessibles.Despite their omnipresence and essential role in our everyday lives, online and printed graphical representations are inaccessible to visually impaired people because they cannot be explored using the sense of touch. The gap between sighted and visually impaired people's access to graphical representations is constantly growing due to the increasing development and availability of online and dynamic representations that not only give sighted people the opportunity to access large amounts of data, but also to interact with them using advanced functionalities such as panning, zooming and filtering. In contrast, the techniques currently used to make maps and diagrams accessible to visually impaired people require the intervention of tactile graphics specialists and result in non-interactive tactile representations. However, based on recent advances in the automatic production of content, we can expect in the coming years a growth in the availability of adapted content, which must go hand-in-hand with the development of affordable and usable devices. In particular, these devices should make full use of visually impaired users' perceptual capacities and support the display of interactive and updatable representations. A number of research prototypes have already been developed. Some rely on digital representation only, and although they have the great advantage of being instantly updatable, they provide very limited tactile feedback, which makes their exploration cognitively demanding and imposes heavy restrictions on content. On the other hand, most prototypes that rely on digital and physical representations allow for a two-handed exploration that is both natural and efficient at retrieving and encoding spatial information, but they are physically limited by the use of a tactile overlay, making them impossible to update. Other alternatives are either extremely expensive (e.g. braille tablets) or offer a slow and limited way to update the representation (e.g. maps that are 3D-printed based on users' inputs). In this thesis, we propose to bridge the gap between these two approaches by investigating how to develop physical interactive maps and diagrams that support two-handed exploration, while at the same time being updatable and affordable. To do so, we build on previous research on Tangible User Interfaces (TUI) and particularly on (actuated) tabletop TUIs, two fields of research that have surprisingly received very little interest concerning visually impaired users. Based on the design, implementation and evaluation of three tabletop TUIs (the Tangible Reels, the Tangible Box and BotMap), we propose innovative non-visual interaction techniques and technical solutions that will hopefully serve as a basis for the design of future TUIs for visually impaired users, and encourage their development and use. We investigate how tangible maps and diagrams can support various tasks, ranging from the (re)construction of diagrams to the exploration of maps by panning and zooming. From a theoretical perspective we contribute to the research on accessible graphical representations by highlighting how research on maps can feed research on diagrams and vice-versa. We also propose a classification and comparison of existing prototypes to deliver a structured overview of current research

Multi-scale Visualization Design for Interactively Analyzing Large Time-series Data

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2014. 2. 서진욱.We propose a unified visualization model, called a ripple graph, that takes the benefits of both of the bar graph and line graph with enhanced graphical integrity for not only the regularly measured but also irregularly measured time-series data. The ripple graph also unveils uncertainty of values between two temporal measurements by varying color intensity depending upon the confidence of the values. In doing so, it can effectively reveal the measurement frequency or interval while still showing the overall temporal pattern of change. We further extend the ripple graph representation into a single unified multi-scale visualization model via an interactive 2D widget to accommodate the advantages of other efficient time-series data visualization techniques while addressing the scalability issue. We have conducted a controlled user study to show the efficacy of the ripple graph by comparing it to existing representations (i.e. line graph, bar graph, and interactive horizon graph), after selecting representative tasks (i.e. Max, Same, Frequency, and Confidence task) for time-series data visualization. Results show that ripple graph is overall the best performing in terms of task time, correctness, and subjective satisfaction across all task types. Following a participatory design process with neurologists, we design an interactive visual exploration tool for time-series data, called Stroscope, based on the ripple graph representation and the widget. Stroscope provides various interactions to navigate data in temporal aspect and supports algorithmic time-series analysis methods to accomplish certain analytical tasks. We have also performed long-term case studies with two neurologists dealing with blood pressure measurements for 1600 stroke patients to show the effectiveness of Stroscope. They have could visually explore individual blood pressure values and their changes over time while maintaining the context, which could lead to save time and effort on exploratory analyses in comparison with using conventional statistical tools. In analyzing blood pressure data, Stroscope enables them to (1) find patients with anomalous patterns, (2) compare between two groups in terms of measurement values, measurement frequency, and fluctuation, (3) confirm what they already knew, and (4) formulate a new hypothesis.Abstract i Contents v List of Figures viii List of Tables xiii Chapter 1 Introduction 1 1.1 Background & Motivation 1 1.2 Main Contribution 6 1.3 Organization of the Dissertation 9 Chapter 2 Related Work 11 2.1 (Large) Time-series data visualization 11 2.2 Event sequences data visualization 16 2.3 Interaction 17 2.4 Evaluation 19 Chapter 3 Problem Analysis 21 3.1 Dataset 22 3.2 A Scenario – Status Quo 24 3.3 Design Process 25 3.4 Design Rationale 26 Chapter 4 Ripple Graph: A Multi-scale Visualization Model for time-series data 29 4.1 Visual Representation 30 4.2 Multi-scale Modeling 32 4.2.1 Dimension zooming with range of interest (ROI) 32 4.2.2 Color mapping to further distinguish bars 33 4.2.3 Moving the horizontal axis 34 4.3 Visualizing degree of certainty between masurements 35 4.4 User interface for ripple graph manipulation 37 4.4.1 Control panel 37 4.4.2 Focus lens 39 Chapter 5 Usability Study 43 5.1 Participants and materials 43 5.2 Tasks 44 5.3 Procedure 46 5.4 Results 48 5.5 Discussion 50 Chapter 6 Controlled User Study 55 6.1 Participants and materials 55 6.2 Visualization techniques 56 6.3 Tasks 57 6.4 Study design and procedure 58 6.5 Results 60 6.6 Discussion 68 Chapter 7 Stroscope 69 7.1 Layout 69 7.2 User Interaction 71 7.3 Analytical Features 74 7.4 Implementation 78 Chapter 8 Case Study 79 8.1 Procedure 79 8.2 Participant 1 (P1) 80 8.3 Participant 2 (P2) 85 8.4 Discussion 89 Chapter 9 Conclusion 93 Bibliography 95 Abstract in Korean 105Docto

Versioning in Interactive Systems

Dealing with past states of an interactive system is often difficult, and users often resort to unwieldy methods such as saving and naming multiple copies. Versioning tools can help users save and manipulate different versions of a document, but traditional tools designed for coding are often unsuitable for interactive systems. Supporting versioning in interactive systems requires investigation of how users think about versions and how they want to access and manipulate past states. We first surveyed users to understand what a ‘version’ means to them in the context of digital interactive work, and the circumstances under which they create new versions or go back to previous ones. We then built a versioning tool that can store versions using a variety of explicit and implicit mechanisms and shows a graphical representation of the version tree to allow easy inspection and manipulation. To observe how users used versions in different work contexts, we tested our versioning tool in two interactive systems – a game level editor and a web analysis tool. We report several new findings about how users of interactive systems create versions and use them as undo alternatives, exploring options, and planning future work. Our results show that versioning can be a valuable component that improves the power and usability of interactive systems. The new understanding that we gained about versioning in interactive environments by developing and evaluating our custom version tool can help us design more effective versioning tools for interactive systems

Visualization of analytic provenance for sensemaking

Sensemaking is an iterative and dynamic process, in which people collect data relevant to their tasks, analyze the collected information to produce new knowledge, and possibly inform further actions. During the sensemaking process, it is difficult for the human’s working memory to keep track of the progress and to synthesize a large number of individual findings and derived hypotheses, thus limits the performance. Analytic provenance captures both the data exploration process and and its accompanied reasoning, potentially addresses these information overload and disorientation problems. Visualization can help recall, revisit and reproduce the sensemaking process through visual representations of provenance data. More interesting and challenging, analytic provenance has the potential to facilitate the ongoing sensemaking process rather than providing only post hoc support. This thesis addresses the challenge of how to design interactive visualizations of analytic provenance data to support such an iterative and dynamic sensemaking. Its original contribution includes four visualizations that help users explore complex temporal and reasoning relationships hidden in the sensemaking problems, using both automatically and manually captured provenance. First SchemaLine, a timeline visualization, enables users to construct and refine narratives from their annotations. Second, TimeSets extends SchemaLine to explore more complex relationships by visualizing both temporal and categorical information simultaneously. Third, SensePath captures and visualizes user actions to enable analysts to gain a deep understanding of the user’s sensemaking process. Fourth, SenseMap visualization prevents users from getting lost, synthesizes new relationship from captured information, and consolidates their understanding of the sensemaking problem. All of these four visualizations are developed using a user-centered design approach and evaluated empirically to explore how they help target users make sense of their real tasks. In summary, this thesis contributes novel and validated interactive visualizations of analytic provenance data that enable users to perform effective sensemaking

Interactive Exploration of Temporal Event Sequences

Life can often be described as a series of events. These events contain rich information that, when put together, can reveal history, expose facts, or lead to discoveries. Therefore, many leading organizations are increasingly collecting databases of event sequences: Electronic Medical Records (EMRs), transportation incident logs, student progress reports, web logs, sports logs, etc. Heavy investments were made in data collection and storage, but difficulties still arise when it comes to making use of the collected data. Analyzing millions of event sequences is a non-trivial task that is gaining more attention and requires better support due to its complex nature. Therefore, I aimed to use information visualization techniques to support exploratory data analysis---an approach to analyzing data to formulate hypotheses worth testing---for event sequences. By working with the domain experts who were analyzing event sequences, I identified two important scenarios that guided my dissertation: First, I explored how to provide an overview of multiple event sequences? Lengthy reports often have an executive summary to provide an overview of the report. Unfortunately, there was no executive summary to provide an overview for event sequences. Therefore, I designed LifeFlow, a compact overview visualization that summarizes multiple event sequences, and interaction techniques that supports users' exploration. Second, I examined how to support users in querying for event sequences when they are uncertain about what they are looking for. To support this task, I developed similarity measures (the M&M measure 1-2) and user interfaces (Similan 1-2) for querying event sequences based on similarity, allowing users to search for event sequences that are similar to the query. After that, I ran a controlled experiment comparing exact match and similarity search interfaces, and learned the advantages and disadvantages of both interfaces. These lessons learned inspired me to develop Flexible Temporal Search (FTS) that combines the benefits of both interfaces. FTS gives confident and countable results, and also ranks results by similarity. I continued to work with domain experts as partners, getting them involved in the iterative design, and constantly using their feedback to guide my research directions. As the research progressed, several short-term user studies were conducted to evaluate particular features of the user interfaces. Both quantitative and qualitative results were reported. To address the limitations of short-term evaluations, I included several multi-dimensional in-depth long-term case studies with domain experts in various fields to evaluate deeper benefits, validate generalizability of the ideas, and demonstrate practicability of this research in non-laboratory environments. The experience from these long-term studies was combined into a set of design guidelines for temporal event sequence exploration. My contributions from this research are LifeFlow, a visualization that compactly displays summaries of multiple event sequences, along with interaction techniques for users' explorations; similarity measures (the M&M measure 1-2) and similarity search interfaces (Similan 1-2) for querying event sequences; Flexible Temporal Search (FTS), a hybrid query approach that combines the benefits of exact match and similarity search; and case study evaluations that results in a process model and a set of design guidelines for temporal event sequence exploration. Finally, this research has revealed new directions for exploring event sequences

Making Sense of Document Collections with Map-Based Visualizations

As map-based visualizations of documents become more ubiquitous, there is a greater need for them to support intellectual and creative high-level cognitive activities with collections of non-cartographic materials -- documents. This dissertation concerns the conceptualization of map-based visualizations as tools for sensemaking and collection understanding. As such, map-based visualizations would help people use georeferenced documents to develop understanding, gain insight, discover knowledge, and construct meaning. This dissertation explores the role of graphical representations (such as maps, Kohonen maps, pie charts, and other) and interactions with them for developing map-based visualizations capable of facilitating sensemaking activities such as collection understanding. While graphical representations make document collections more perceptually and cognitively accessible, interactions allow users to adapt representations to users’ contextual needs. By interacting with representations of documents or collections and being able to construct representations of their own, people are better able to make sense of information, comprehend complex structures, and integrate new information into their existing mental models. In sum, representations and interactions may reduce cognitive load and consequently expedite the overall time necessary for completion of sensemaking activities, which typically take much time to accomplish. The dissertation proceeds in three phases. The first phase develops a conceptual framework for translating ontological properties of collections to representations and for supporting visual tasks by means of graphical representations. The second phase concerns the cognitive benefits of interaction. It conceptualizes how interactions can help people during complex sensemaking activities. Although the interactions are explained on the example of a prototype built with Google Maps, they are independent iv of Google Maps and can be applicable to various other technologies. The third phase evaluates the utility, analytical capabilities and usability of the additional representations when users interact with a visualization prototype – VIsual COLlection EXplorer. The findings suggest that additional representations can enhance understanding of map-based visualizations of library collections: specifically, they can allow users to see trends, gaps, and patterns in ontological properties of collections

Exploratory Browsing

In recent years the digital media has influenced many areas of our life. The transition from analogue to digital has substantially changed our ways of dealing with media collections. Today‟s interfaces for managing digital media mainly offer fixed linear models corresponding to the underlying technical concepts (folders, events, albums, etc.), or the metaphors borrowed from the analogue counterparts (e.g., stacks, film rolls). However, people‟s mental interpretations of their media collections often go beyond the scope of linear scan. Besides explicit search with specific goals, current interfaces can not sufficiently support the explorative and often non-linear behavior. This dissertation presents an exploration of interface design to enhance the browsing experience with media collections. The main outcome of this thesis is a new model of Exploratory Browsing to guide the design of interfaces to support the full range of browsing activities, especially the Exploratory Browsing. We define Exploratory Browsing as the behavior when the user is uncertain about her or his targets and needs to discover areas of interest (exploratory), in which she or he can explore in detail and possibly find some acceptable items (browsing). According to the browsing objectives, we group browsing activities into three categories: Search Browsing, General Purpose Browsing and Serendipitous Browsing. In the context of this thesis, Exploratory Browsing refers to the latter two browsing activities, which goes beyond explicit search with specific objectives. We systematically explore the design space of interfaces to support the Exploratory Browsing experience. Applying the methodology of User-Centered Design, we develop eight prototypes, covering two main usage contexts of browsing with personal collections and in online communities. The main studied media types are photographs and music. The main contribution of this thesis lies in deepening the understanding of how people‟s exploratory behavior has an impact on the interface design. This thesis contributes to the field of interface design for media collections in several aspects. With the goal to inform the interface design to support the Exploratory Browsing experience with media collections, we present a model of Exploratory Browsing, covering the full range of exploratory activities around media collections. We investigate this model in different usage contexts and develop eight prototypes. The substantial implications gathered during the development and evaluation of these prototypes inform the further refinement of our model: We uncover the underlying transitional relations between browsing activities and discover several stimulators to encourage a fluid and effective activity transition. Based on this model, we propose a catalogue of general interface characteristics, and employ this catalogue as criteria to analyze the effectiveness of our prototypes. We also present several general suggestions for designing interfaces for media collections