1,720,965 research outputs found
A cell classifier for RRAM process development (Dataset)
No full textDevices that exhibit resistive switching are promising components for future nanoelectronics with applications ranging from emerging memory to neuromorphic computing and biosensors. In this work, we present an algorithm for identifying switchable devices i.e. devices that can be programmed in distinct resistive states and which change their state predictably and repeatably in response to input stimuli. The method is based on extrapolating the statistical significance of difference in between two distinct resistive states as measured from devices subjected to standardised bias protocols. The test routine is applied on distinct elements of 32x32 RRAM crossbar arrays and yields a measure of device switchability in the form of a statistical significance pvalue. Ranking devices by p-value shows that switchable devices are typically found in the bottom 10% and are therefore easily distinguishable from non-functional devices. Implementation of this algorithm dramatically cuts RRAM testing time by granting fast access to the best devices in each array as well as yield metrics.</span
Emulating short-term synaptic dynamics with memristive devices
No full textNeuromorphic architectures offer great promise for achieving computation capacities beyond conventional Von Neumann machines. The essential elements for achieving this vision are highly scalable synaptic mimics that do not undermine biological fidelity. Here we demonstrate that single solid-state TiO2 memristors can exhibit non-associative plasticity phenomena observed in biological synapses, supported by their metastable memory state transition properties. We show that, contrary to conventional uses of solid-state memory, the existence of rate-limiting volatility is a key feature for capturing short-term synaptic dynamics. We also show how the temporal dynamics of our prototypes can be exploited to implement spatio-temporal computation, demonstrating the memristors full potential for building biophysically realistic neural processing systems.</span
Unsupervised learning in probabilistic neural networks with multi-state metal-oxide memristive synapses
No full textIn an increasingly data-rich world the need for developing computing systems that cannot only process, but ideally also interpret big data is becoming continuously more pressing. Brain-inspired concepts have shown great promise towards addressing this need. Here we demonstrate unsupervised learning in a probabilistic neural network that utilizes metal-oxide memristive devices as multi-state synapses. Our approach can be exploited for processing unlabelled data and can adapt to time-varying clusters that underlie incoming data by supporting the capability of reversible unsupervised learning. The potential of this work is showcased through the demonstration of successful learning in the presence of corrupted input data and probabilistic neurons, thus paving the way towards robust big-data processors
An FPGA-based instrument for en-masse RRAM characterization with ns pulsing resolution
No full textAn FPGA-based instrument with capabilities of on-board oscilloscope and nanoscale pulsing (70 ns @ \pm 10 V) is presented, thus allowing exploration of the nano-scale switching of RRAM devices. The system possesses less than 1% read-out error for resistance range between 1 text{k}\Omega to 1 text{M}\Omega , and demonstrated its functionality on characterizing solid-state prototype RRAM devices on wafer; devices exhibiting gradual switching behavior under pulsing with duration spanning between 30 ns to 100 \µs. The data conversion error-induced degradation on read-out accuracy is studied extensively and verified by standard linear resistor measurements. The integrated oscilloscope capability extends the versatility of our instrument, rendering a powerful tool for processing development of emerging memory technologies but also for testing theoretical hypotheses arising in the new field of memristors
Live demonstration: characterization of RRAM crossbar arrays at a click of a button
Full text linkWe demonstrate a desktop platform which has the ability of fully characterizing RRAM crossbar arrays while not compromising on ease-of-use. The setup consists of our bespoke PCB system connected to a local PC (laptop), on which a Pyhton interface allows the user to directly interact with individual RRAM cells packaged in either crossbar or stand-alone configurations. The platform is capable of current-compliant forming among other exotic pulsing schemes, used for exposing IV and switching characteristics or utilising the devices for a wide range of applications. These operations can be applied on one, or several cells, in an automated fashion, drastically accelerating data acquisition
Emulating short-term synaptic dynamics with memristive devices
Full text linkNeuromorphic architectures offer great promise for achieving computation capacities beyond conventional Von Neumann machines. The essential elements for achieving this vision are highly scalable synaptic mimics that do not undermine biological fidelity. Here we demonstrate that single solid-state TiO2 memristors can exhibit non-associative plasticity phenomena observed in biological synapses, supported by their metastable memory state transition properties. We show that, contrary to conventional uses of solid-state memory, the existence of rate-limiting volatility is a key feature for capturing short-term synaptic dynamics. We also show how the temporal dynamics of our prototypes can be exploited to implement spatio-temporal computation, demonstrating the memristors full potential for building biophysically realistic neural processing systems
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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