Alfie Abdul-Rahman

An Empirical Study on Using Visual Embellishments in Visualization

In written and spoken communications, figures of speech (e.g., metaphors and synecdoche) are often used as an aid to help convey abstract or less tangible concepts. However, the benefits of using rhetorical illustrations or embellishments in visualization have so far been inconclusive. In this work, we report an empirical study to evaluate hypotheses that visual embellishments may aid memorization, visual search and concept comprehension. One major departure from related experiments in the literature is that we make use of a dual-task methodology in our experiment. This design offers an abstraction of typical situations where viewers do not have their full attention focused on visualization (e.g., in meetings and lectures). The secondary task introduces “divided attention”, and makes the effects of visual embellishments more observable. In addition, it also serves as additional masking in memory-based trials. The results of this study show that visual embellishments can help participants better remember the information depicted in visualization. On the other hand, visual embellishments can have a negative impact on the speed of visual search. The results show a complex pattern as to the benefits of visual embellishments in helping participants grasp key concepts from visualization.

Rule-based visual mappings - with a case study on poetry visualization

In this paper, we present a user‐centered design study on poetry visualization. We develop a rule‐based solution to address the conflicting needs for maintaining the flexibility of visualizing a large set of poetic variables and for reducing the tedium and cognitive load in interacting with the visual mapping control panel. We adopt Munzners nested design model to maintain high‐level interactions with the end users in a closed loop. In addition, we examine three design options for alleviating the difficulty in visualizing poems latitudinally. We present several example uses of poetry visualization in scholarly research on poetry.

Spectral Volume Rendering based on the Kubelka-Munk Theory

Colour realism plays an important role in computer graphics and visualization. In this paper, we present a new approach to direct volume rendering based on the Kubelka-Munk theory of diffuse reflectance. We show that not only the Kubelka-Munk theory facilitates a correct spectral volume rendering integral suitable for both solid objects and amorphous matters in volume datasets, but also provides volume visualization with more accurate optical effects than the traditional volume rendering integral based on the RGBα accumulation. We discuss the design of transfer functions for specifying absorption and scattering coefficients, and the use of post-illumination for integrating pre-processed reflectance images in real time. We demonstrate the optical realism achieved by this approach with a combination of several natural and artificial colour datasets.

I Know Where You Live: Inferring Details of People's Lives by Visualizing Publicly Shared Location Data

This research measures human performance in inferring the functional types (i.e., home, work, leisure and transport) of locations in geo-location data using different visual representations of the data (textual, static and animated visualizations) along with different amounts of data (1, 3 or 5 day(s)). We first collected real life geo-location data from tweets. We then asked the data owners to tag their location points, resulting in ground truth data. Using this dataset we conducted an empirical study involving 45 participants to analyze how accurately they could infer the functional location of the original data owners under different conditions, i.e., three data representations, three data densities and four location types. The study results indicate that while visual techniques perform better than textual ones, the functional locations of human activities can be inferred with a relatively high accuracy even using only textual representations and a low density of location points. Workplace was more easily inferred than home while transport was the functional location with the highest accuracy. Our results also showed that it was easier to infer functional locations from data exhibiting more stable and consistent mobility patterns, which are thus more vulnerable to privacy disclosures. We discuss the implications of our findings in the context of privacy preservation and provide guidelines to users and companies to help preserve and safeguard peoples privacy.

A Multi-task Comparative Study on Scatter Plots and Parallel Coordinates Plots

Previous empirical studies for comparing parallel coordinates plots and scatter plots showed some uncertainty about their relative merits. Some of these studies focused on the task of value retrieval, where visualization usually has a limited advantage over reading data directly. In this paper, we report an empirical study that compares user performance, in terms of accuracy and response time, in the context of four different visualization tasks, namely value retrieval, clustering, outlier detection, and change detection. In order to evaluate the relative merits of the two types of plots with a common base line (i.e., reading data directly), we included three forms of stimuli, data tables, scatter plots, and parallel coordinate plots. Our results show that data tables are better suited for the value retrieval task, while parallel coordinates plots generally outperform the two other visual representations in three other tasks. Subjective feedbacks from the users are also consistent with the quantitative analyses. As visualization is commonly used for aiding multiple observational and analytical tasks, our results provided new evidence to support the prevailing enthusiasm for parallel coordinates plots in the field of visualization.

Quill : a framework for constructing negotiated texts: with a case study on the US constitutional convention of 1787

This paper describes a new approach to the presentation of records relating to formal negotiations and the texts that they create. It describes the architecture of a model, platform, and web-interface (https://www.quillproject.net) that can be used by domain-experts to convert the records typical of formal negotiations in to a model of decision-making (with minimal training). This model has implications for both research and teaching, by allowing for better qualitative and quantitative analysis of negotiations. The platform emphasizes the reconstruction as closely as possible of the context within which proposals and decisions are made. A generic platform, its usability, and benefits are illustrated by a presentation of the records relating to the 1787 Constitutional Convention that wrote the Constitution of the United States.

Constructive Visual Analytics for Text Similarity Detection

Detecting similarity between texts is a frequently encountered text mining task. Because the measurement of similarity is typically composed of a number of metrics, and some measures are sensitive to subjective interpretation, a generic detector obtained using machine learning often has difficulties balancing the roles of different metrics according to the semantic context exhibited in a specific collection of texts. In order to facilitate human interaction in a visual analytics process for text similarity detection, we first map the problem of pairwise sequence comparison to that of image processing, allowing patterns of similarity to be visualized as a 2D pixelmap. We then devise a visual interface to enable users to construct and experiment with different detectors using primitive metrics, in a way similar to constructing an image processing pipeline. We deployed this new approach for the identification of commonplaces in 18th‐century literary and print culture. Domain experts were then able to make use of the prototype system to derive new scholarly discoveries and generate new hypotheses.

Designing a Research Platform for Engaged Learning

This panel addresses the opportunities and challenges of using multi-institutional collaborations and digital approaches to drive engaged-learning and archive-focused projects. It focuses in particular on the opportunities presented by the archives related to the negotiation of constitutions and international treaties.

VisGuides: A Forum for Discussing Visualization Guidelines

This paper presents VisGuides, a discussion platform to facilitate the collection, evaluation, critique, revision, and dissemination of visualization guidelines. As visualization becomes a more widespread discipline with much more attention by designers and the general public, we need to ensure mechanisms for communicating, transferring, and accessing visualization knowledge. A visualization guideline can be anything ranging from good practices, empirical studies, and survey reports with the goal to inform visualization design and understanding. Thus, our forum aims (i) to collect visualization guidelines, (ii) to discuss guidelines and collect respective empirical references, and in the long run, (iii) to establish formal knowledge about guidelines by analyzing the forum content and the consensus of discussions. This paper describes the VisGuides forum and outlines our preliminary research towards shedding more light on visualization guidelines. VisGuides is accessible online at visguides.org.

Re-spatialization of time series plots

Visualizing time series is a ubiquitous aspect of many applications from science to business. The conventional designs of line graphs and temporal parallel coordinates plots focus on the depiction of the temporal context, but typically fail to convey the spatial information associated with data values at each time step. In this paper, we present a study of the design space for reintroducing spatial context to time series plots. We consider a range of options, from color encoding to glyph encoding, from abstract illustration to realistic representation, and from interactive brushing to animated three-dimensional viewing. We evaluate these design options in conjunction with two case studies: (i) observing events in temporal sensory data of seafloor hydrothermal plumes and (ii) observing phonemic dynamics in poems. We report domain experts’ comparative assessment, which provides an insight into the effectiveness of different re-spatialization methods.