1,720,974 research outputs found
Analytical Modeling of Current Overshoot in Oxide-Based Resistive Switching Memory (RRAM)
Full text linkCurrent overshoot due to parasitic capacitance during set transition represents a major concern for controlling the resistance and current consumption in resistive switching memory (RRAM) arrays. In this letter, the impact of current overshoot on the low-resistance state (LRS) is evaluated by means of experiments on one-transistor/one-resistor structures of HfO2 RRAM. We develop a physics-based analytical model, able to calculate the LRS resistance and the corresponding reset current by a closed-form formula. The model allows predicting the current overshoot impact for any value of compliance current, set voltage, and parasitic capacitance
Memristive and CMOS Devices for Neuromorphic Computing
Full text linkNeuromorphic computing has emerged as one of the most promising paradigms to overcome the limitations of von Neumann architecture of conventional digital processors. The aim of neuromorphic computing is to faithfully reproduce the computing processes in the human brain, thus paralleling its outstanding energy efficiency and compactness. Toward this goal, however, some major challenges have to be faced. Since the brain processes information by high-density neural networks with ultra-low power consumption, novel device concepts combining high scalability, low-power operation, and advanced computing functionality must be developed. This work provides an overview of the most promising device concepts in neuromorphic computing including complementary metal-oxide semiconductor (CMOS) and memristive technologies. First, the physics and operation of CMOS-based floating-gate memory devices in artificial neural networks will be addressed. Then, several memristive concepts will be reviewed and discussed for applications in deep neural network and spiking neural network architectures. Finally, the main technology challenges and perspectives of neuromorphic computing will be discussed
Physical Unbiased Generation of Random Numbers With Coupled Resistive Switching Devices
Full text linkSynaptic realizations based on memristive devices
Full text linkIn the past 10 years, neuromorphic computing has emerged as a novel approach to tackle the challenges posed by the end of Moore’s law. Memristive devices are very promising due to their unique properties. They are highly compact, fast switching, power efficient, and can represent multiple states of memory (via a tunable resistance). As such they can find use as synaptic connections among neurons in biologically inspired hardware neural networks, and therefore could be a critical element for the development of hardware cognitive systems with capabilities such as those found in animal nervous systems. In this chapter, we present an overview on the current status of synaptic circuits based on memristive devices. We review various implementations including the single-memristor synapse, which employs resistive switching random access memory, phase-change memory and spin-transfer torque magnetic random access memory, hybrid structures combining complementary metal-oxide semiconductor transistors, and memristive devices and materials-based approaches aiming at reproducing biological learning rules by the physical properties of the device. Learning rules such as the spike-timing-dependent plasticity, the spike-rate-dependent plasticity and the short-term plasticity are described. We finally present some examples of learning circuits exploited in hardware neural networks, which make initial steps on a path toward memristive circuits capable of biorealistic brain-inspired cognitive computing
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
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