The dataflow model : a characterization and a data exploration tool

Doctoral ColloquiumInternational audienceCurrent Air Traffic Control (ATC) activities employ two kinds of visualization systems: real-time traffic views, which are used by Air Traffic Controllers (ATCos) to monitor aircraft positions, and data analysis systems, used by experts to analyze past traffic recording (e.g. conflict analysis or traffic workload forecast). Both types of systems employ complex and dynamic visualizations, displaying hundreds of data that must be understandable with the minimum of cognitive workload

The Physiological User's Response as a Clue to Assess Visual Variables Effectiveness

International audienceThe paper deals with the introduction of Bertin's visual variables in an ATC context. The ranking of the efficiency of these variables has been experimentally verified by Cleveland, however, no studies highlight the physiological correlates of this ranking. We analyzed behavioral, physiological and subjective data recorded on 7 healthy subjects facing a visual comparison task witch involve 5 selected visual characterizations (angle, text, surface, framed rectangles and luminosity). Results showed that the observed accuracy was coherent with Mackinlay ranking of visual variables. Psychophysiological and subjective measurements are also discussed

Exploration of aircraft trails by Air Traffic Experts

International audienceIn this paper, we describe a set of applications and findings performed by Air Traffic Control (ATC) experts while interactively exploring recorded aircraft trails. ATC experts deal with recorded radar data (aircraft positions, altitude, time, etc). This large quantity of information spoils their visualization with a lot of occlusion and cluttering. With a simple paradigm of brush, pick and drop, users can intuitively filter the dataset by direct manipulation of trails. Through applied examples, we show how a visualization tool and its real time applications take advantage of human vision and are therefore assets for data exploration and validation. This tool allows the visualization and the interaction with large quantity of information, hence enabling overview of the dataset at a whole and quick retrieval of insights

Scan path visualization and comparison using visual aggregation techniques

We demonstrate the use of different visual aggregation techniques to obtain non-cluttered visual representations of scanpaths. First, fixation points are clustered using the mean-shift algorithm. Second, saccades are aggregated using the Attribute-Driven Edge Bundling (ADEB) algorithm that handles a saccades direction, onset timestamp, magnitude or their combination for the edge compatibility criterion. Flow direction maps, computed during bundling, can be visualized separately (vertical or horizontal components) or as a single image using the Oriented Line Integral Convolution (OLIC) algorithm. Furthermore, cosine similarity between two flow direction maps provides a similarity map to compare two scanpaths. Last, we provide examples of basic patterns, visual search task, and art perception. Used together, these techniques provide valuable insights about scanpath exploration and informative illustrations of the eye movement data

Techniques de bundling : un cas d'étude pour l'exploration de grandes quantités d'informations

We present a fast and simple method to compute bundled layouts of general graphs, dynamic graphs and temporal paths. For this, we first transform a given graph drawing into a density map using kernel density estimation. Next, we apply an image sharpening technique which progressively merges local height maxima by moving the convolved graph edges into the height gradient flow. We show how these techniques can produce simplified visualizations of static, streaming and sequence graphs. We illustrate our techniques with datasets from aircraft monitoring, software engineering, and eye-tracking of static and dynamic scenes

Amélioration du circuit visuel des contrôleurs aériens pour relier les données entre visualisations en utilisant des transitions animées

International audienceSeveral separate displays are used by Air Traffic Controllers, such as radar view, flight lists view or paper strips. In order to link the information between these views and keep focus on a subset of flights, controllers are required to do visual operations (eye gaze, analysis of visual properties etc.). This process can be disruptive when traffic increases and when visualizations display large amounts of objects. In this paper we propose the use of animated transitions to replace the visual paths controllers take. We discuss this technique and show results of a predictive evaluation that suggests an improvement in users' performance

From Visualization to Association Rules : an automatic approach

International audienceThe main goal of Data Mining is the research of relevant information from a huge volume of data. It is generally achieved either by automatic algorithms or by the visual exploration of data. Thanks to algorithms, an exhaustive set of patterns matching specific measures can be found. But the volume of extracted information can be greater than the volume of initial data. Visual Data Mining allows the specialist to focus on a specific area of data that may describe interesting patterns. However, it is often limited by the difficulty to deal with a great number of multi dimensional data. In this paper, we propose to mix an automatic and a manual method, by driving the automatic extraction using a data scatter plot visualization. This visualization affects the number of rules found and their construction. We illustrate our method on two databases. The first describes one month French air traffic and the second stems from 2012 KDD Cup database

Formulating the design rationale of visual representation

8pWhen designing a representation, a designer implicitly formulates a method required to understand and use the representation effectively. This paper aims at making the method explicit, in order to help designers elicit their design choices. In particular, we present a set of concepts to systematically analyze what a user must theoretically do visually to find information. The analysis consists in a decomposition of the activity of scanning into elementary visualization operations. We show how the analysis applies on various existing representation, and how expected benefits can be expressed in terms of elementary operations. The decomposition highlights the challenges encountered by a user when figuring out a representation, and helps designer to exhibit possible flaws in their design.The set of elementary operations form the basis of a shared, common language for representation designers

A descriptive model of visual scanning

International audienceWhen designing a representation, a designer implicitly formulates a sequence of visual tasks required to understand and use the representation effectively. This paper aims to make the sequence of visual tasks explicit, in order to help designers eliciting their design choices. In particular, we present a set of concepts to systematically analyze what a user must theoretically do to decipher representation. The analysis consists of a decomposition of the activity of scanning into elementary visualization operations. We show how the analysis applies to various existing representations, and how expected benefits can be expressed in terms of elementary operations. The set of elementary operations form the basis of a shared, common language for representation designers. The decomposition highlights the challenges encountered by a user when deciphering a representation, and helps designers to exhibit possible flaws in their design, justify their choices, and compare designs