Frame of Reference Interaction.

We present a unified set of 3D interaction techniques that demonstrates an alternative way of thinking about the navigation of large virtual spaces in non-immersive environments. Our alternative conceptual framework views navigation from a cognitive perspective—as a way of facilitating changes in user attention from one reference frame to another—rather than from the mechanical perspective of moving a camera between different points of interest. All of our techniques link multiple frames of reference in some meaningful way. Some techniques link multiple windows within a zooming environment while others allow seamless changes of user attention between static objects, moving objects, and groups of moving objects. We present our techniques as they are implemented in GeoZui3D, a geographic visualization system for ocean dat

Integrating Multiple 3D Views through Frame-of-reference Interaction

Frame-of-reference interaction consists of a unified set of 3D interaction techniques for exploratory navigation of large virtual spaces in nonimmersive environments. It is based on a conceptual framework that considers navigation from a cognitive perspective, as a way of facilitating changes in user attention from one reference frame to another, rather than from the mechanical perspective of moving a camera between different points of interest. All of our techniques link multiple frames of reference in some meaningful way. Some techniques link multiple windows within a zooming environment while others allow seamless changes of user focus between static objects, moving objects, and groups of moving objects. We present our techniques as they are implemented in GeoZui3D, a geographic visualization system for ocean data

Target Acquisition in Multiscale Electronic Worlds

Since the advent of graphical user interfaces, electronic information has grown exponentially, whereas the size of screen displays has stayed almost the same. Multiscale interfaces were designed to address this mismatch, allowing users to adjust the scale at which they interact with information objects. Although the technology has progressed quickly, the theory has lagged behind. Multiscale interfaces pose a stimulating theoretical challenge, reformulating the classic target-acquisition problem from the physical world into an infinitely rescalable electronic world. We address this challenge by extending Fitts’ original pointing paradigm: we introduce the scale variable, thus defining a multiscale pointing paradigm. This article reports on our theoretical and empirical results. We show that target-acquisition performance in a zooming interface must obey Fitts’ law, and more specifically, that target-acquisition time must be proportional to the index of difficulty. Moreover, we complement Fitts’ law by accounting for the effect of view size on pointing performance, showing that performance bandwidth is proportional to view size, up to a ceiling effect. The first empirical study shows that Fitts’ law does apply to a zoomable interface for indices of difficulty up to and beyond 30 bits, whereas classical Fitts’ law studies have been confined in the 2-10 bit range. The second study demonstrates a strong interaction between view size and task difficulty for multiscale pointing, and shows a surprisingly low ceiling. We conclude with implications of these findings for the design of multiscale user interfaces

Exploratory Visualization of Astronomical Data on Ultra-high-resolution Wall Displays

International audienceUltra-high-resolution wall displays feature a very high pixel density over a large physical surface, which makes them well-suited to the collaborative, exploratory visualization of large datasets. We introduce FITS-OW, an application designed for such wall displays, that enables astronomers to navigate in large collections of FITS images, query astronomical databases, and display detailed, complementary data and documents about multiple sources simultaneously. We describe how astronomers interact with their data using both the wall's touch-sensitive surface and handheld devices. We also report on the technical challenges we addressed in terms of distributed graphics rendering and data sharing over the computer clusters that drive wall displays

The design and evaluation of interfaces for navigating gigapixel images in digital pathology

This paper describes the design and evaluation of two generations of an interface for navigating datasets of gigapixel images that pathologists use to diagnose cancer. The interface design is innovative because users panned with an overview:detail view scale difference that was up to 57 times larger than established guidelines, and 1 million pixel ‘thumbnail’ overviews that leveraged the real-estate of high resolution workstation displays. The research involved experts performing real work (pathologists diagnosing cancer), using datasets that were up to 3150 times larger than those used in previous studies that involved navigating images. The evaluation provides evidence about the effectiveness of the interfaces, and characterizes how experts navigate gigapixel images when performing real work. Similar interfaces could be adopted in applications that use other types of high-resolution images (e.g., remote sensing or highthroughput microscopy)

SurfaceConstellations: A Modular Hardware Platform for Ad-Hoc Reconfigurable Cross-Device Workspaces

We contribute SurfaceConstellations, a modular hardware platform for linking multiple mobile devices to easily create novel cross-device workspace environments. Our platform combines the advantages of multi-monitor workspaces and multi-surface environments with the flexibility and extensibility of more recent cross-device setups. The SurfaceConstellations platform includes a comprehensive library of 3D-printed link modules to connect and arrange tablets into new workspaces, several strategies for designing setups, and a visual configuration tool for automatically generating link modules. We contribute a detailed design space of cross-device workspaces, a technique for capacitive links between tablets for automatic recognition of connected devices, designs of flexible joint connections, detailed explanations of the physical design of 3D printed brackets and support structures, and the design of a web-based tool for creating new SurfaceConstellation setups

Linking focus and context in three-dimensional multiscale environments

The central question behind this dissertation is this: In what ways can 3D multiscale spatial information be presented in an interactive computer graphics environment, such that a human observer can better comprehend it? Toward answering this question, a two-pronged approach is employed that consists of practice within computer user-interface design, and theory grounded in perceptual psychology, bound together by an approach to the question in terms of focus and context as they apply to human attention. The major practical contribution of this dissertation is the development of a novel set of techniques for linking 3D windows to various kinds of reference frames in a virtual scene and to each other---linking one or more focal views with a view that provides context. Central to these techniques is the explicit recognition of the frames of reference inherent in objects, in computer-graphics viewpoint specifications, and in the human perception and cognitive understanding of space. Many of these techniques are incorporated into the GeoZui3D system as major extensions. An empirical evaluation of these techniques confirms the utility of 3D window proxy representations and orientation coupling. The major theoretical contribution is a cognitive systems model that predicts when linked focus and context views should be used over other techniques such as zooming. The predictive power of the model comes from explicit recognition of locations where a user will focus attention, as well as applied interpretations of the limitations of visual working memory. The model\u27s ability to predict performance is empirically validated, while its ability to model user error is empirically founded. Both the model and the results of the related experiments suggest that multiple linked windows can be an effective way of presenting multiscale spatial information, especially in situations involving the comparison of three or more objects. The contributions of the dissertation are discussed in the context of the applications that have motivated them

Geometria de canais de comunicação

Orientador: Marcelo FirerTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação CientíficaResumo: Abordamos os canais de comunicação a partir de um ponto de vista geométrico. Mostramos que a decodificação por máxima verossimilhança e a decodificação por mínima distância são um caso particular de uma forma mais geral de decodificação que pode ser definida para qualquer matriz. Com base nisso, definimos uma equivalência de decodificação e mostramos que ela divide o espaço de matrizes em classes de equivalência que são regiões generalizadas de um arranjo de hiperplanos bem conhecido. Em seguida, definimos uma distância entre essas regiões que mede a probabilidade de um código aleatório ser decodificado incorretamente. Mostramos que esta distância é uma versão ponderada da distância de Kendall tau. Com isso, obtemos uma distância entre canais. Se para um canal existe uma métrica de modo que os decodificadores por máxima verossimilhança e mínima distância coincidem, o canal é metrizavel. Damos caracterizações para um canal ser metrizavel e apresentamos um algoritmo que constrói uma métrica nesse caso. Mostramos também que qualquer métrica, a menos de uma equivalência de decodificação, pode ser mergulhada isometricamente no hipercubo com a métrica de Hamming e, portanto, em termos de decodificação, a métrica de Hamming é universal. Apresentamos um algoritmo que, para qualquer métrica invariante por translação, dá um limite superior na dimensão mínima de tal mergulho. Encontramos também limitantes inferiores e superiores para essa dimensão. No apêndice, apresentamos uma contribuição teórica feita a um trabalho de navegação de mapasAbstract: We approach communication channels from a geometrical viewpoint. We show that maximum likelihood decoding and minimum distance decoding are a particular case of a more general form of decoding which can be defined for any matrix. Based on this we define a decoding equivalence and show that it partitions the space of matrices into equivalence classes which are generalized regions of a well known hyperplane arrangement: the braid arrangement. We then define a distance between these regions which measures the probability of a random code being decoded incorrectly. It is shown that this distance is a weighted variation of the Kendall tau distance. With this, we obtain a distance between channels. If for a channel there exists a metric such that the maximum likelihood and minimum distance decoders coincide, the channel is metrizable. We give characterizations for a channel to be metrizable and present an algorithm which constructs a metric in such a case. We also show that any metric, up to decoding equivalence, can be isometrically embedded into the hypercube with the Hamming metric, and thus, in terms of decoding, the Hamming metric is universal. We then present an algorithm which for any translation invariant metric gives an upper bound on the minimum dimension of such an embedding. We also give lower and upper bounds for this embedding dimension over the set of all such metrics. In the appendix we present the theoretical contribution made to a work on multi-scale navigationDoutoradoMatematica AplicadaDoutor em Matemática AplicadaCAPE