1,721,038 research outputs found
A recipe for creating ideal hybrid memristive-CMOS neuromorphic processing systems
Full text linkChicca E, Indiveri G. A recipe for creating ideal hybrid memristive-CMOS neuromorphic processing systems. Applied Physics Letters. 2020;116(12): 120501
A Neuromorphic VLSI Implementation of a Simplified Electrosensory System in a Weakly Electric Fish
Full text linkAamir SA, Engelmann J, Gomez L, Chicca E. A Neuromorphic VLSI Implementation of a Simplified Electrosensory System in a Weakly Electric Fish. Presented at the International Workshop on Neuromorphic and Brain-Based Computing Systems (NeuComp 2013), Grenoble, France
A systematic method for configuring VLSI networks of spiking neurons
Full text linkNeftci E, Chicca E, Indiveri G, Douglas RJ. A systematic method for configuring VLSI networks of spiking neurons. Neural Computation. 2011;23(10):2457-2497.An increasing number of research groups are developing custom hybrid analog/digital very large scale integration (VLSI) chips and systems that implement hundreds to thousands of spiking neurons with biophysically realistic dynamics, with the intention of emulating brainlike real-world behavior in hardware and robotic systems rather than simply simulating their performance on general-purpose digital computers. Although the electronic engineering aspects of these emulation systems is proceeding well, progress toward the actual emulation of brainlike tasks is restricted by the lack of suitable high-level configuration methods of the kind that have already been developed over many decades for simulations on general-purpose computers. The key difficulty is that the dynamics of the CMOS electronic analogs are determined by transistor biases that do not map simply to the parameter types and values used in typical abstract mathematical models of neurons and their networks. Here we provide a general method for resolving this difficulty. We describe a parameter mapping technique that permits an automatic configuration of VLSI neural networks so that their electronic emulation conforms to a higher-level neuronal simulation. We show that the neurons configured by our method exhibit spike timing statistics and temporal dynamics that are the same as those observed in the software simulated neurons and, in particular, that the key parameters of recurrent VLSI neural networks (e. g., implementing soft winner-take-all) can be precisely tuned. The proposed method permits a seamless integration between software simulations with hardware emulations and intertranslatability between the parameters of abstract neuronal models and their emulation counterparts. Most important, our method offers a route toward a high-level task configuration language for neuromorphic VLSI systems
Firing proprieties of an adaptive analog VLSI neuron
Full text linkBen Dayan Rubin D, Chicca E, Indiveri G. Firing proprieties of an adaptive analog VLSI neuron. Presented at the Proceedings of Bio-ADIT, Lausanne, Switzerland.We describe the response properties of a compact, low power, analog circuit that implements a model of a leaky I&F neuron, with spike-frequency adaptation, refractory period and voltage threshold modulation properties. We investigate the statistics of the circuit's output response by modulation its operating parameters, like refractory period and adaptation level and by changing the statistics of the input current. The results show a clear match with theoretical and neurophysiological data in a given range of the parameter space. This analysis defines the chip's parameter working range and predicts its behavior in case of integration into large massively parallel VLSI networks
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
Stochastic synaptic plasticity in deterministic aVLSI networks of spiking neurons
Full text linkChicca E, Fusi S. Stochastic synaptic plasticity in deterministic aVLSI networks of spiking neurons. In: Rattay F, ed. Proceedings of the World Congress on Neuroinformatics. Vienna: ARGESIM/ASIM Verlag; 2001: 468-477.Stochastic learning solves the stability-plasticity problem (Fusi et al., 2000a)
but raises new issues related to the generation of the proper noise driving
the synaptic dynamics. Here we show that a simple, fully deterministic,
spike-driven synaptic device can make use of the network generated vari-
ability in the neuronal activity to drive the required stochastic mechanism.
Randomness emerges naturally from the interaction of deterministic neu-
rons, and no extra source of noise is needed. Learning and forgetting
rates of the network can be easily controlled by changing the statistics of
the spike trains without changing any inherent parameter of the synaptic
dynamics
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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