1,720,970 research outputs found
A Memristive Pixel Architecture for Real-Time Tracking
No full textWe report on a pixel architecture relying on memristive devices to perform pixel-level adaptive background subtraction. Core of the processing is the pixel, containing a Light-To-Frequency (L2F) converter. Its output digital pulses, proportional to the intensity of light, are applied in turn to a memristor, changing its resistance accordingly. Two additional memristors are used to store the dynamic boundaries, outside which the behaviour of the photo-generated signal is recognised to be anomalous, i.e., unexpectedly fast-changing. The main advantages of using memristors over all-CMOS implementations are a smaller pixel pitch and non-volatility, the latter allowing the image background to be modelled with programmable time constants
Modelling Small Brushless Motors: an Alternative Approach using Confomal Transformations
No full textA memristor-based pixel implementing light-to-resistance conversion
No full textThis letter reports a pixel architecture that implements a light-to-resistance encoder exploiting the properties of a memristor. A light-to-frequency (L2F) converter is adopted to drive a memristor with pulses, thus changing its resistance according with the light intensity. In a conventional L2F implementation, a binary counter is needed to store the number of pulses generated within the exposure time (Ti). In the proposed circuit, the binary counter has been replaced with an analog counterpart, made of a single memristor. This turns into a smaller pixel pitch, compared with an all-CMOS solution and analog nonvolatile characteristics. The proposed circuit has been simulated in a 3.3 V, 0.35 μm CMOS process, while the memristor behavior relies on the HP model
Memristor-based pixel for event-detection vision sensor
No full textWe report on a vision sensor architecture relying on a pixel-embedded memristive device to perform dynamic background subtraction as basic image processing components, aimed at detecting anomalous events in the scene. A Light-To-Frequency Converter generates digital pulses, which are linearly proportional with the light intensity. During the exposure time, a certain number of pulses, with proper width and amplitude, drive the memristor MS, changing its resistance. The value of MS is then compared with two memristors, MH and ML, used as thresholds. After each frame, the values of MH and ML are adjusted in order to satisfy ML < MS < MH. The rate at which the two memristors are updated is application-dependent and can be digitally programmed. If the value of MS trespasses either MH or ML, due to a light change, the pixel behaviour is recognized as anomalous (hot-pixel) By aggregating the hot-pixels of the image, anomalous events can be detected through standard processing techniques. The pixel architecture has been designed in a 0.35μm standard CMOS process and validated through simulation
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
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