1,720,987 research outputs found
Supercapacitor-enabled energy-autonomous wireless sensor node for sustainable and remote sensing applications
No full textThis paper presents an energy-autonomous and battery-free wireless sensor node that is self-powered through photovoltaic energy harvesting. The system uses a small value capacitor to perform sensing activity and wireless communication continuously when energy source is present and a supercapacitor to store energy for use when energy source is not present. The system embeds a single off-the-shelf integrated circuit embedding a microcontroller that performs power management and wire- less connectivity functions. The microcontroller implements a finite-state machine that cyclically manages energy harvesting, sensing, wireless communication, and energy storage. The system also implements Bluetooth low-energy connectivity. The proposed wireless node addresses the issue of battery replacement in wireless sensor nodes, which is a significant challenge in many applications. The system’s energy autonomy and battery-free operation make it ideal for use in remote and hard-to-reach locations where battery replacement is difficult or impossible. The experimental results demonstrate the system’s effectiveness in energy harvesting, power management, and wireless commu- nication. The proposed device offers a promising solution for energy-efficient and sustainable wireless sensor networks
Influence of common source and word line electrodes on program operation in superflash memory
No full textA theoretical study of the influence of word line and common source electrodes on the program operation in shrank SuperFlash memory is proposed. Numerical simulations demonstrate that the literature model defined for previous nodes is not always suitable, due to the continuous cell physical size reduction and to the consequent increment of capacitive coupling between the floating gate and adjacent electrodes. To get a deeper insight, an analytical model of the electric field in the region of source side injection is proposed. This model describes the impact of the cell physical and electrical parameters on the vertical and horizontal field components and highlights the strong dependence of the carrier injection on the technology node. Furthermore, the numerical and analytical models estimate the influence of the word line and common source electrodes on the time‐toprogram, the floating gate potential and the source side injection efficiency, taking into consideration, at the same time, their possible impact on the cell reliability
Toward A Quantitative Evaluation of the Fall Risk Using the Fusion of Inertial Signals and Electromyography with Wearable Sensors
No full textFreezing of Gait (FOG) is an unpredictable gait disorder typical of Parkinson's Disease (PD). The main goals of this work are detecting FOG episodes, classifying FOG subtypes and analyzing the leg muscles activity toward a deeper insight into the disorder pathophysiology and in the associated risk of fall. Fusion of inertial and electromyographic signals in our wearable system allows distinguishing correctly 98.4% of FOG episodes and monitoring in free-living conditions the activity type and intensity of leg antagonist muscles involved in FOG. This is an advancement in the state-of-art knowledge of PD pathophysiology, possibly allowing the implementation of current therapeutic strategies
On border traps in back-side-illuminated CMOS image sensor oxides
Full text linkCMOS image sensors (CISs) in back-side-illuminated configuration consist of photodiode arrays having metal lines and drive electronics beneath the active region with respect to the device/air interface so that the light reaches the photodiode active region directly. This enhances sensor quantum efficiency but reduces the electrical performance and reliability. The back-side configuration is realized by flipping the wafer upside down, bonding it to a handling wafer, mechanically thinning it, and opening a through-silicon via with a long plasma etch. As a result, gate oxides in back-side CISs show an increased density of donor-like border traps with respect to the conventional front-side-illuminated sensors. In this article, we try to add some information toward the comprehension of the origin and the electrical nature of those traps in back-side gate oxides. To this aim, we performed negative bias temperature instability stress on p-channel MOSFETs during which the traps were filled by holes tunneling from the substrate and then studied the relaxation transients of the drain current after the stress was removed. The characteristic emission times of a few specific levels were obtained at different temperatures. This allowed us to extract values of the trap activation energies, which resulted coherent with hole-capturing E′ donor-like centers (trivalent silicon dangling bonds) commonly attributed to ionizing radiation
A neural network implemented on NAND memory
No full textThis article describes how a NAND memory device is adapted to the implementation of an artificial neural network. To this aim, a new hardware realization of the elementary synapse (called here "Synaptic Cell") is proposed. Furthermore, a method for connecting neurons to form a multilayer ANN is proposed with necessary algorithms to run it. Some examples of neural behavior, like function approximation and classification are reported
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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