Toward Visualization-Specific Heuristic Evaluation

This position paper describes heuristic evaluation as it relates to visualization and visual analytics. We review heuristic evaluation in general, then comment on previous process-based, performance-based, and framework-based efforts to adapt the method to visualization-specific needs. We postulate that the framework-based approach holds the most promise for future progress in development of visualization-specific heuristics, and propose a specific framework as a starting point. We then recommend a method for community involvement and input into the further development of the heuristic framework and more detailed design and evaluation guidelines

The Potential of Virtual Heritage Reconstruction in Lost Ansonborough

The virtual reconstruction of vanished heritage is a well-known practice in the preservation field. The constant development in computer technologies has been improving visualization and interpretation techniques for virtual reconstructions of no longer extant or inaccessible sites. Reconstruction projects of vanished heritage sites implement various approaches because of different challenges at each site. This research involves 3D reconstructions, as well as historical research of early nineteenth century residences, Radcliffe-King and Gabriel Manigault houses in the Ansonborough neighborhood of Charleston, South Carolina, USA. The demolition of these two mansions in the first half of the twentieth century leads to the loss of the residential character at the intersection of George and Meeting Streets in Ansonborough. Photogrammetry and rectification techniques established the dimensions and the scale for these buildings from salvaged architectural details and early photographs to recreate the lost residential character. Other sources, like maps and drawings are used to supplement the photographs and salvaged materials for virtual reconstruction

Naturalistic Cognition: A Research Paradigm for Human-Centered Design

Naturalistic thinking and knowing, the tacit, experiential, and intuitive reasoning of everyday interaction, have long been regarded as inferior to formal reason and labeled primitive, fallible, subjective, superstitious, and in some cases ineffable. But, naturalistic thinking is more rational and definable than it appears. It is also relevant to design. Inquiry into the mechanisms of naturalistic thinking and knowledge can bring its resources into focus and enable designers to create better, human-centered designs for use in real-world settings. This article makes a case for the explicit, formal study of implicit, naturalistic thinking within the fields of design. It develops a framework for defining and studying naturalistic thinking and knowledge, for integrating them into design research and practice, and for developing a more integrated, consistent theory of knowledge in design. It will (a) outline historical definitions of knowledge, attitudes toward formal and naturalistic thinking, and the difficulties presented by the co-presence of formal and naturalistic thinking in design, (b) define and contrast formal and naturalistic thinking as two distinct human cognitive systems, (c) demonstrate the importance of naturalistic cognition in formal thinking and real-world judgment, (d) demonstrate methods for researching naturalistic thinking that can be of use in design, and (e) briefly discuss the impact on design theory of admitting naturalistic thinking as valid, systematic, and knowable

Establishing usability heuristics for heuristics evaluation in a specific domain: is there a consensus?

Heuristics evaluation is frequently employed to evaluate usability. While general heuristics are suitable to evaluate most user interfaces, there is still a need to establish heuristics for specific domains to ensure that their specific usability issues are identified. This paper presents a comprehensive review of 70 studies related to usability heuristics for specific domains. The aim of this paper is to review the processes that were applied to establish heuristics in specific domains and identify gaps in order to provide recommendations for future research and area of improvements. The most urgent issue found is the deficiency of validation effort following heuristics proposition and the lack of robustness and rigour of validation method adopted. Whether domain specific heuristics perform better or worse than general ones is inconclusive due to lack of validation quality and clarity on how to assess the effectiveness of heuristics for specific domains. The lack of validation quality also affects effort in improving existing heuristics for specific domain as their weaknesses are not addressed

Doctor of Philosophy

dissertationThe present study explored data presentation and human cognition with the objective of improving electronic Decision Support Systems (DSS). Computers have been used as tools for decision support for over 60 years, with the intent to supplement or replace human cognition. However, electronic computing has failed to reliably replace human cognition in complex domains. The suboptimal properties of the data and complexities of the domain often require human interpretation and intervention. Human interpretation relies on experience, values, intuition, insight and learning; which can lead to shortcuts or heuristics. Heuristics in the correct context can be economical and effective in solving many problems. When heuristics fail the results are labeled as cognitive biases or errors. Biases all share the elements of structuring incorrect or inappropriate models or hypotheses and/or insufficient consideration of the data. Most biases can be linked to confirmation bias - which is manifested by searches for and consideration of only confirming data. De-biasing techniques share the concept of shifting cognitive processing from an automatic associative mode to a more deliberate, conscious rule-based mode. This study used a modified Wason 2-4-6 task that combined methods of, 1) increased salience through data visualization with 2) appealing to the rule-based system through task instructions. The results indicate that neither increased salience nor instructions ensure increased search sufficiency, efficiency or decision accuracy. However, this study provides insight into the perceived value of evidence and iv four potential limitations related to self-directed searches: 1) The selection of necessary disconfirming evidence cannot be assumed, regardless of the perceived value of disconfirming evidence. 2) The selection of sufficient evidence does not ensure accuracy; however, 3) insufficient selection of disconfirming evidence results in lower accuracy. 4) Ambiguous evidence is considered more valuable than potentially disconfirming evidence. Implications for the design of decision support systems are presented along with limitations and directions for future research

A Task-Centered Visualization Design Environment and a Method for Measuring the Complexity of Visualization Designs

Recent years have seen a growing interest in the emerging area of computer security visualization which is about developing visualization methods to help solve computer security problems. In this thesis, we will first present a method for measuring the complexity of information visualization designs. The complexity is measured in terms of visual integration, number of separable dimensions for each visual unit, the complexity of interpreting the visual attributes, number of visual units, and the efficiency of visual search. This method is designed to better assist fellow developers to quickly evaluate multiple design choices, potentially enables computer to automatically measure the complexity of visualization data. We will also analyze the design space of network security visualization. Our main contribution is a new taxonomy that consists of three dimensions – data, visualizations, and tasks. Each dimension is further divided into hierarchical layers, and for each layer we have identified key parameters for making major design choices. This new taxonomy provides a comprehensive framework that can guide network security visualization developers to systematically explore the design space and make informed design decisions. It can also help developers or users systematically evaluate existing network security visualization techniques and systems. Finally it helps developers identify gaps in the design space and create new techniques. Taxonomy showed that most of the existing computer security visualization programs are data centered. However, some studies have shown that task centered visualization is perhaps more effective. To test this hypothesis, we propose a task centered visualization design framework, in which tasks are explicitly identified and organized and visualizations are constructed for specific tasks and their related data parameters. The center piece of this framework is a task tree which dynamically links the raw data with automatically generated visualization. The task tree serves as a high level interaction technique that allows users to conduct problem solving naturally at the task level, while still giving end users flexible control over the visualization construction. This work is currently being extended by building a prototype visualization system based on a Task-centered Visualization Design Architecture

Evaluating Sketchy Lines for the Visualization of Qualitative Uncertainty

We report on results of a series of user studies on the perception of visual variables that are commonly used in the literature to depict uncertainty. To the best of our knowledge, we provide the first formal evaluation of the use of these variables to facilitate an easier reading of uncertainty in visualizations that rely on line graphical primitives. In addition to blur, dashing and grayscale, we investigate the use of 'sketchiness' as a visual variable because it conveys visual impreciseness that may be associated with data quality. Inspired by work in non-photorealistic rendering and by the features of hand-drawn lines, we generate line trajectories that resemble hand-drawn strokes of various levels of proficiency--ranging from child to adult strokes--where the amount of perturbations in the line corresponds to the level of uncertainty in the data. Our results show that sketchiness for the visualization of uncertainty in lines is as intuitive as blur; although people subjectively prefer dashing style over blur, grayscale and sketchiness. We discuss advantages and limitations of each technique and conclude with design considerations on how to deploy these visual variables to effectively depict various levels of uncertainty for line marks.Nous rapportons les résultats d'études utilisateurs sur la perception de variables visuelles qui sont couramment utilisées dans la littérature pour représenter l'incertitude. A notre connaissance, nous rapportons la première évaluation formelle de l'utilisation de ces variables pour faciliter la lecture de l'incertitude dans des visualisations qui reposent sur des lignes graphiques primitives. En plus du flouté, des pointillés et des niveaux de gris, nous avons étudié l'utilisation du dessin á main levée comme variable visuelle parce qu'il transmet l'imprécision qui peut être associée á la qualité des données. Inspirés par les travaux sur NPR (Non-Photorealistic Rendering) et par l'aspect des lignes tracées á la main, nous avons généré des trajectoires linéaires ressemblant á des traits dessinés á la main, et correspondant á différents niveaux de compétence--allant de l'enfant á l'adulte--pour lesquels la quantité de perturbations dans la ligne correspondait au niveau d'incertitude des données. Nos résultats montrent que l'utilisation du dessin á main levée pour la visualisation de l'incertitude dans les lignes est aussi intuitive que le flouté, bien qu'intuitivement les personnes préfèrent subjectivement les pointillés au flou, aux niveaux de gris ainsi qu'au dessin á main levée. Nous discutons les avantages et les limites de chaque technique et nous concluons sur des considérations de conception, concernant comment déployer ces variables visuelles pour représenter efficacement plusieurs niveaux d'incertitude pour des repères linéaires

Entwicklung und Evaluation von Feedbacktechniken in der Softwarevisualisierung

Innovative und komplexe Informationssysteme erfordern zur Erfassung neuartige Analysewerkzeuge. Dazu dienen in der Softwarevisualisierung Modelle zur Darstellung und Interaktionstechniken zur Steuerung. Ein Teilgebiet der Interaktionstechniken sind Feedbacktechniken, die dem Benutzer Rückmeldungen auf Interaktionen liefern. In der vorliegenden Arbeit werden bestehende Feedbacktechniken eingeordnet und neue entwickelt. Anhand von drei Prototypen werden unterschiedliche Feedbacktechniken vorgestellt und implementiert. Abschließend werden die Techniken auf ihre Nützlichkeit getestet. Dazu wird eine explorative Evaluation konzipiert, durchgeführt und ausgewertet.:Gliederung Abbildungsverzeichnis Listings Tabellenverzeichnis Abkürzungsverzeichnis 1 Einleitung 1.1 Motivation und Problemstellung 1.2 Zielstellung 1.3 Aufbau der Arbeit 2 Interaktionstechniken in der Softwarevisualisierung 2.1 Softwarevisualisierung 2.2 Interaktionstechniken 2.3 Bewertung von User-Interfaces 2.4 Stand der Forschung 3 Entwicklung von Feedbacktechnologie für SV 3.1 Taxonomien für ITecs 3.2 Vorhandene ITecs in SV 3.3 Konzeption neuer Feedbacktechniken für SV 3.4 Implementierung und Funktionsweise 4 Erhebung zur Messung des Nutzens von ITecs 4.1 Theoretische Grundlagen und Methodik der Erhebung 4.1.1 Methoden zur Evaluation von Software 4.1.2 Wahl einer Evaluationsmethode 4.2 Konzeption und Versuchsaufbau 4.3 Durchführung 5 Evaluation des Nutzens von ITecs 5.1 Stichprobenbeschreibung 5.2 Auswertung, Priorisierung und Klassifikation der Ergebnisse 5.3 Interpretation 5.4 Diskussion 6 Fazit und Ausblic