1,720,959 research outputs found
Multi-touch and Tangible Interface: Two Different Interaction Modes in the Same System
No full textWe present here a system built around the idea of giving to several users the possibility to interact with a cheap and solid hardware, at the same time, using natural gestures supported
by an intuitive user interface. A projector and a camera are placed underneath a Plexiglas sheet, framed with an array of infrared LEDs, all set into a wooden table box. This allows for multiple users (up to four or ve) to freely move around the box and manipulate the objects retro-projected
on the screen, using a tangible interface designed aiming at offering few simple operations: geometric transforms (rotations,
translations and scales), drawing, erasing and color
se-lections. All of these are executed through the use of either a custom built IR LED pen and/or directly the fingers. The main purpose of the project is to offer an instrument of tangible interaction to classrooms of naive users (i.e.: neither
technology nor science professors and students) in a
university environment
Tracing Field‐Coherent Quad Layouts
No full textGiven a cross field over a triangulated surface we present a practical and robust method to compute a field aligned coarse quad layout over the surface. The method works directly on a triangle mesh without requiring any parametrization and it is based on a new technique for tracing field-coherent geodesic paths directly on a triangle mesh, and on a new relaxed formulation of a binary LP problem, which allows us to extract both conforming quad layouts and coarser layouts containing t-junctions. Our method is easy to implement, very robust, and, being directly based on the input cross field, it is able to generate better aligned layouts, even with complicated fields containing many singularities. We show results on a number of datasets and comparisons with state-of-the-art methods
Data-driven interactive quadrangulation
No full textWe propose an interactive quadrangulation method based on a large collection of patterns that are learned from models manually designed by artists. The patterns are distilled into compact quadrangulation rules and stored in a database. At run-time, the user draws strokes to define patches and desired edge flows, and the system queries the database to extract fitting patterns to tessellate the sketches' interiors. The quadrangulation patterns are general and can be applied to tessellate large regions while controlling the positions of the singularities and the edge flow. We demonstrate the effectiveness of our algorithm through a series of live retopology sessions and an informal user study with three professional artists
Animation-Aware Quadrangulation
No full textGeometric meshes that model animated characters must be designed while taking into account the deformations that the shape will undergo during animation. We analyze an input sequence of meshes with point-to-point correspondence, and we automatically produce a quadrangular mesh that fits well the input animation. We first analyze the local deformation that the surface undergoes at each point, and we initialize a cross field that remains as aligned as possible to the principal directions of deformation throughout the sequence. We then smooth this cross field based on an energy that uses a weighted combination of the initial field and the local amount of stretch. Finally, we compute a field-aligned quadrangulation with an off-the-shelf method. Our technique is fast and very simple to implement, and it significantly improves the quality of the output quad mesh and its suitability for character animation, compared to creating the quad mesh based on a single pose. We present experimental results and comparisons with a state-of-the-art quadrangulation method, on both sequences from 3D scanning and synthetic sequences obtained by a rough animation of a triangulated model
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Content-Aware Quad Meshing
No full textQuadrilateral meshes are preferred over triangular meshes in the animation and CAD industry, mostly because they fit well the role of control grids for higher-level digital representations of smooth surfaces, such as subdivision surfaces and NURBS. Nonetheless, most software and hardware designed for 3D visualization and also most acquisition technology are optimized to generate highly accurate triangular meshes. Due to their different properties, triangular and quadrilateral meshes have led each to different types of applications, even in different scientific disciplines. While algorithms for analysis and processing of geometric data, operating on each of these two representations, have been developed more or less independently, researches have been putting efforts into the design of methods to convert from one to the other. Such methods can be divided into two main categories: automatic and user-assisted. Currently, though, no automatic method is able to produce quadrilateral meshes that can be directly employed in the animation pipeline. This is mainly because of the weak or non-existent connection between any surface geometry and its ideal, application-dependent quad mesh. For example, if the mesh was intended to be used for animation, its connectivity should be tailored to its articulation and optimized to reduce skinning deformation artifacts. It is not possible to extract this kind of information merely from the geometry of a static mesh. In this thesis we investigate the problem of converting a dense, triangular mesh into a coarse, highly structured, quadrilateral mesh, suitable to flow into the standard pipeline of production in the animation industry. We discuss what properties are required and what are the most commonly used methods that can be employed for this goal. Based on such properties, we develop some novel solutions. In particular, we present three different methods. The first one generates meshes with structurally sound patch layout. This means that a high level layout of the surface patches is the objective. The layout of the patches should resemble the layout of the logical parts of an object. The second method introduces a way to drive the quadrangulation with the object deformations expected in an animation sequence. We show that such knowledge is necessary but not always available or complete. Finally, the last method overcomes the shortcomings of the previous ones by allowing the user to sketch the high-level patch layout connectivity in an intuitive and interactive manner. We employed a data-driven approach, which provides precise control over every single aspect of the mesh, without the drawbacks of the classical, manual methods, but leveraging the expertise contained implicitly into other, well-designed, quadrilateral meshes
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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