A unified data representation theory for network visualization, ordering and coarse-graining

Representation of large data sets became a key question of many scientific disciplines in the last decade. Several approaches for network visualization, data ordering and coarse-graining accomplished this goal. However, there was no underlying theoretical framework linking these problems. Here we show an elegant, information theoretic data representation approach as a unified solution of network visualization, data ordering and coarse-graining. The optimal representation is the hardest to distinguish from the original data matrix, measured by the relative entropy. The representation of network nodes as probability distributions provides an efficient visualization method and, in one dimension, an ordering of network nodes and edges. Coarse-grained representations of the input network enable both efficient data compression and hierarchical visualization to achieve high quality representations of larger data sets. Our unified data representation theory will help the analysis of extensive data sets, by revealing the large-scale structure of complex networks in a comprehensible form.Comment: 13 pages, 5 figure

The traces left by the information designer. Data visualization and enunciation

A common understanding considers information design to be a clear and immediate transfer of information, in which the author disappears to make the data emerge with utmost clarity. This idea of infographics as a transparent and objective medium is questioned by several scholars and practitioners who consider visualization not just as a representation of numbers, but as an interpretative device. In this essay, we will review these positions, with special regard to the use of the semiotic concept of enunciation, which is also beginning to be used in critical design theory and digital humanities. This concept allows us to detect the traces of the act of enunciation in the visual artefact. In particular, we will deal with the recognition of visualization as an act of interpretation, the visual calibration and distancing from one’s statement in journalism and scientific communication and the visual reference to the production process in graphic design

The emergence of scientific understanding in current ecological research practice

Scientific understanding as a subject of inquiry has become widely discussed in philosophy of science and is often addressed through case studies from history of science. Even though these historical reconstructions engage with details of scientific practice, they usually provide only limited information about the gradual formation of understanding in ongoing processes of model and theory construction. Based on a qualitative ethnographic study of an ecological research project, this article shifts attention from understanding in the context of historical case studies to evidence of current case studies. By taking de Regt's (2017) contextual theory of scientific understanding into the field, it confirms core tenets of the contextual theory (e.g. the crucial role of visualization and visualizability) suggesting a normative character with respect to scientific activities. However, the case study also shows the limitations of de Regt's latest version of this theory as an attempt to explain the development of understanding in current practice. This article provides a model representing the emergence of scientific understanding that exposes main features of scientific understanding such as its gradual formation, its relation to skills and imagination, and its capacity for knowledge selectivity. The ethnographic evidence presented here supports the claim that something unique can be learned by looking into ongoing research practices that can’t be gained by studying historical case studies

Visualizing Non-Equilibrium Flow Simulations using 3-D Velocity Distribution Functions

Scientific visualization techniques have been used to probe and understand better the physics of non-equilibrium flows. A visualization methodology for nonequilibrium flow simulations using 3-D velocity distribution functions (VDFs) is illustrated in application to various non-equilibrium flow problems. A one-dimensional normal shock wave problem is considered for two different upstream Mach numbers corresponding to weak and strong non-equilibrium flow conditions. The iso-surfaces of 3-D VDFs inside the shock wave obtainedusing various solution techniques including the ES-BGK method, DSMC technique, Mott-Smith solution, and the Navier-Stokes (NS) distribution functions using Chapman-Enskog theory are compared and contrasted. The visualization technique is extended to two-dimensional hypersonic flow at M-19 past a flat plate with sharp leading edge by comparing the isosurfaces of 3-D NS VDFs obtained at three different locations in the flowfield. The visualization of 3-D VDFs is shown to provide valuable information about the degree and direction of non-equilibrium for both 1-D and 2-D flows

design e visualização de informação

Tese de mestrado, Design de comunicação e novos media, Universidade de Lisboa, Faculdade de Belas Artes, 2011A definition of Information Visualization is presented, and an objective justification of the importance of this discipline and its crucial role in knowledge is also put forward, based on concrete evidence and conclusions from corroborated scientific research in the fields of physiology and psychology of human vision. From the analysis of the most notable epistemological frameworks on Design, a line is drawn between Design and Information Visualization, uncovering a family resemblance that leads us to conclude this discipline can be placed inside the field of Design, and, given the fact that the fulcrum of Information Visualization is in the production of visual representations, it is more appropriately placed within the universe of Communication Design. Finally, a taxonomy of Information Visualization is presented, picking up from an analysis and synthesis of those previous contributions deemed to offer the most relevant characterizations of each component in the taxonomy here developed. Other components are included in the presented taxonomy, found through a generalization of the concepts that underlie those entities and processes which are central to Information Visualization theory and practice. Future use of this taxonomy may provide formulations to analyse, classify, evaluate and create Information Visualization application

Building on faults:how to represent controversies with digital methods

In a previous article appeared in this journal, I introduced Bruno Latour’s cartography of controversies and I discussed half of it, namely how to observe techno-scientific controversies. In this article I will concentrate on the remaining half: how to represent the complexity of social debates in a legible form. In my previous paper, we learnt how to explore the richness of collective existence through Actor-Network Theory. In this one, I will discuss how to render such complexity through an original visualization device: the controversy-website. Capitalizing on the potential of digital technologies, the controversy-website has been developed as a multilayered toolkit to trace and aggregate information on public debates

Information visualization for the people

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Comparative Media Studies, 2008.Includes bibliographical references (p. 85-89).The design of information visualization, defined as the interactive, graphical presentation of data, is on the verge of a significant paradigm shift brought on by the continued maturation of the Information Age. Its traditional role as a scientific tool deployed by rigorous data analysts is in the process of expanding to include more mainstream uses and users, reflecting fundamental changes to the role of information and data in our increasingly digital society. However, visualization design theory remains rooted in earlier conceptions of its use, largely ignoring the needs of this new, non-expert audience. Accordingly, this thesis attempts to re-contextualize information visualization as a public-facing practice, and explores ways in which its design can shift from being described as "by experts, for experts" to a new characterization as "for the people."by Michael Danziger.S.M

A Trace Macroscopic Description based on Time Aggregation

Trace visualization; trace analysis; trace overview; time aggregation; parallel systems; embedded systems; information theory; scientific computation; multimedia application; debugging; optimizationToday, because of computing system complexity, it is required to trace application executions to understand their behavior. Visualization techniques provide some help in representing their content, but their scalability is limited both because of human perception and bounded screen resolution. To solve this issue, we propose a visualization based on time aggregation that provides a concise overview of a trace whatever its size. The level of details in this visualization can be configurable by users who can adjust the compromise between concision (gain from aggregation) and information loss. They can then refine their analysis by zooming in an interesting part and choosing a less aggregated overview for this interesting part. This visualization is implemented in our tool, Ocelotl, which enables users to interact with this visualization by changing the selected time interval and its aggregation settings dynamically. The results presented in this paper show that the technique can help users correctly identify anomalies in very large trace files composed of up to forty million events.De nos jours, à cause de la complexité des systèmes actuels, les analystes utilisent le traçage pour comprendre le comportement des programmes. Les techniques de visualisation aident à représenter le contenu de ces traces, mais le passage à l'échelle est limité par la perception humaine des données affichées ainsi que par la résolution des écrans. Dans le but de résoudre ce problème, nous proposons une technique de visualisation faisant appel à une algorithme d'agrégation, fournissant un aperçu du contenu de la trace quelle que soit sa taille. Le niveau de détail peut être ajusté par l'utilisateur, grâce à un compromis entre la réduction de complexité de la représentation (gain dû à l'agrégation) et la perte d'information. L'utilisateur peut ensuite raffiner l'analyse en zoomant sur des parties intéressantes de la trace et en diminuant l'intensité de l'agrégation. Cette technique est implémentée dans notre outil, Ocelotl, qui permet à l'utilisateur d'interagir avec la visualisation en changeant les bornes de temps et les paramètres de l'agrégation de manière dynamique. Les résultats présentés dans ce rapport montrent que notre contribution aide les utilisateurs à identifier des anomalies dans des traces contenant jusqu'à quarante millions d'événements

Visualizing latent domain knowledge

Knowledge discovery and data mining commonly rely on finding salient patterns of association from a vast amount of data. Traditional citation analysis of scientific literature draws insights from strong citation patterns. Latent domain knowledge, in contrast to the mainstream domain knowledge, often consists of highly relevant but relatively infrequently cited scientific works. Visualizing latent domain knowledge presents a significant challenge to knowledge discovery and quantitative studies of science. We build upon a citation-based knowledge visualization procedure and develop an approach that not only captures knowledge structures from prominent and highly cited works, but also traces latent domain knowledge through low-frequency citation chains. We apply this approach to two cases: (1) identifying cross-domain applications of Pathfinder networks (PFNETs) and (2) clarifying the current status of scientific inquiry of a possible link between Bovine spongiform encephalopathy (BSE), also known as mad cow disease, and a new variant Creutzfeldt-Jakob disease (vCJD), a type of brain disease in human

From Social Simulation to Integrative System Design

As the recent financial crisis showed, today there is a strong need to gain "ecological perspective" of all relevant interactions in socio-economic-techno-environmental systems. For this, we suggested to set-up a network of Centers for integrative systems design, which shall be able to run all potentially relevant scenarios, identify causality chains, explore feedback and cascading effects for a number of model variants, and determine the reliability of their implications (given the validity of the underlying models). They will be able to detect possible negative side effect of policy decisions, before they occur. The Centers belonging to this network of Integrative Systems Design Centers would be focused on a particular field, but they would be part of an attempt to eventually cover all relevant areas of society and economy and integrate them within a "Living Earth Simulator". The results of all research activities of such Centers would be turned into informative input for political Decision Arenas. For example, Crisis Observatories (for financial instabilities, shortages of resources, environmental change, conflict, spreading of diseases, etc.) would be connected with such Decision Arenas for the purpose of visualization, in order to make complex interdependencies understandable to scientists, decision-makers, and the general public.Comment: 34 pages, Visioneer White Paper, see http://www.visioneer.ethz.c