1,721,036 research outputs found
A 3 Cent Recognizer: Simple and effective retrieval and classification of mid-air gestures from single 3D traces
No full textIn this paper we present a simple 3D gesture recognizer based on trajectory matching, showing its good performances in classification and retrieval of command gestures based on single hand trajectories. We demonstrate that further simplifications in porting the classic "1 dollar" algorithm approach from the 2D to the 3D gesture recognition and retrieval problems can result in very high classification accuracy and retrieval scores even on datasets with a large number of different gestures executed by different users. Furthermore, recognition can be good even with heavily subsampled path traces and with incomplete gestures
3D Data segmentation using a non-parametric density estimation approach
No full textIn this paper, a new segmentation approach for sets of 3D unorganized points is proposed. The method is based on
a clustering procedure that separates the modes of a non-parametric multimodal density, following the mean-shift
paradigm. The main idea consists in projecting the source 3D data into a set of independent sub-spaces, forming
a joint multidimensional space. Each sub-space describes a geometric aspect of the data set, such as the normals
and principal curvatures, so as a dense region in a particular sub-space indicates a set of 3D points sharing
a similar value of that feature. A non-parametric clustering method is applied in this joint space by using a
multidimensional kernel. This kernel smoothly takes into account for all the subspaces, moving towards high
density regions in the joint space, separating them and providing “natural” clusters of 3D points. The algorithm
can be implemented very easily and only few parameters need to be freely tuned. Experiments are reported, both
on synthetic and real data, assessing the quality of the proposed approach and promoting further developments
Single-Handed vs. Two Handed Manipulation in Virtual Reality: A Novel Metaphor and Experimental Comparisons
No full textIn this paper we present a novel solution for single-handed deviceless object manipulation (e.g. picking/translating, rotating and scaling) in immersive visualization environments. The new method is based on degree of freedom (DOF) separation and on the idea of activating unambiguous gesture recognition when the hand is close to the object, giving visual feedback about gesture realization and available transitions. Furthermore, it introduces a novel metaphor, the "knob", to map hand rotation onto object rotation around selected axes. The solution was tested with users on a classical visualization task related to finding a point of interest in a 3D object and compared with the well known "Handlebar" metaphor. The metaphor shows a reasonable usability, even if not comparable with the bi- manual solution, particularly suited for the tested task. However, given the relevant improvements with task repetitions and the technical issues that can be solved improving the performances, the method seems to be a viable solution for deviceless single-hand manipulation
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
Polycube-based decomposition for fabrication
No full textIn recent years, fabrication technologies developed at a very fast pace. However, some limitations on shape and dimension still apply both to additive and subtractive manufacturing, and one way to bypass them could be the subdivision of the object to build. We present here a simple algorithm, based on the polycube representation of the original shape, able to decompose any model into simpler portions that are better fabricable. The shape is first mapped in a polycube and, then, split to take advantage of the simple polycube subdivision, thus having, quite easily, a partition of the model at hand. The main aim of this work is to study and analyse pros and cons of this simple subdivision scheme for fabrication, in view of using both the additive and subtractive pipelines. The proposed subdivision scheme is computationally light and it produces quite good results, especially when it is applied to models that can be easily decomposed in a small collection of cuboids. The obtained subdivisions are suitable for 3D printing
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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