1,720,967 research outputs found
A Smooth Approximation of Mobile Platform Displacement for Mobile Haptic Interfaces
No full textOne of most interesting aspects in haptic research
deals with the extension of application workspace, thus
allowing haptic simulation within large virtual environments. Several devices have been realized that allow
this kind of interaction, in particular our interest focuses on mobile haptic interfaces, realized by combining
classic grounded haptic devices with mobile platforms.
While grounded haptic interfaces feature fast sampling
rate and finest quantization, mobile haptic interfaces are
multirate devices where the displacement sampling of
mobile platform may affect the quality of haptic rendering. In this paper we introduce a simple smoothing algorithm that allows to approximate a slow-rate and roughquantized sampled signal representing mobile robot displacement with a fast rate and smooth signal. Evaluation experiments confirmed that the proposed algorithm
allows to preserve a good quality of haptic rendering
SimWinding: Sistema di progettazione e prototipazione virtuale 3D di avvolgimenti elettrici stratificati con simulazione fisica.
No full textSimWinding è uno strumento applicativo per il progetto e la prototipazione virtuale di avvolgimenti elettrici stratificati, con simulazione dinamica del task di deposizione. SimWinding è il frutto di una collaborazione fra università e industria volta alla ricerca di modelli e algoritimi di simulazione fisica e allo sviluppo di una metodologia di progetto innovativa. L'obiettivo è velocizzare la messa a punto delle macchine avvolgitrici e ridurre tempi e costi di prototipazione, con il supporto di strumenti di progetto 2D e 3D, di simulazione e di analisi dei prototipi virtuali
Iterative estimation of the end-effector apparent gravity force for 3DoF impedance haptic devices
No full textThe position-dependent apparent gravity acting on
the end-effector of impedance haptic devices may represent
a loss of transparency, and generally requires to be actively
compensated. To that purpose, a new approach to the problem
of gravity compensation was introduced in our previous work
[1]. The apparent gravity is preliminarily estimated in a given
set of positions inside the workspace, then the acquired data
are used to set up a suitable gravity compensation control
law. At each position of the aforementioned set, the estimation
is performed via an iterative method based on a nonlinear
model subject to a feedback-linearizing PD controller. This
paper, which builds upon our previous contribution, improves
the mathematical formulation of the problem and addresses
the analysis of stability and convergence properties of the
iterative estimation method. Finally guidelines for performancebased parameter design are discussed. Validation experiments
have been performed, and results are in good agreement with
theoretical findings
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
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
Perceptibility of digital watermarking in haptically enabled 3D meshes
No full textUsage of 3D data and models is receiving a growing interest for
several applications, like training, museum displays, multimodal
interfaces, aid for impaired people. In such a framework the need
will soon raise to protect 3D data from misuse. Among the technologies that can be used to this aim, digital watermarking has a
prominent role, due to its versatility and non-obtrusiveness. A basic requirement of any watermarking scheme is that the embedded
code is invisible, or non-perceivable, by the end user of the data.
This requirement also holds for 3D objects, it is then necessary that
the human ability of perceiving a signal hidden in a 3D object is
studied. In this paper we present a preliminary analysis aiming
at comparing the perceptibility of the hidden signal when the 3D
model is sensed through different senses, namely vision (through
common rendering techniques and subsequent display on a monitor) and touch (through a haptic interface). Specifically our investigation aimed at assessing whether ensuring watermark invisibility is sufficient to ensure that the watermark presence can not be
felt haptically. The answer stemming from our preliminary analysis seems to be no, even if further studies are necessary before a
definitive answer can be given
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