19,533 research outputs found
Using behavioral modeling and simulation for learning communication circuits and systems
Comunicación presentada al "Global Engineering Education Conference (EDUCON)" celebrado en Marrakech (Marruecos) del 17 al 20 de Abril del 2012.This paper analyzes the use of behavioral simulation techniques to enhance the teaching-learning process in electrical engineering courses, specifically those dealing with circuits for communication systems. The method - which can be applied to both undergraduate and master courses - allows students to better understand complex circuit- and device-level phenomena, by describing them at a higher abstraction level. As a demonstration vehicle of the presented methodology, two examples are considered in this work: an analog front-end of a direct-conversion digital radio receiver and a ΣΔ modulator. In both cases, behavioral models of the different subcircuits have been implemented in MATLAB/SIMULINK and used by the students enrolled in two different courses: an undergraduate course and a master course. The results presented in this paper reveal that students become highly motivated and satisfied with the course contents and the proposed simulation-based learning methodology.This work has been supported in part by the Spanish Ministry of Science and Innovation (with support from the European Regional Development Fund) under contracts TEC2007-67247-C02-01/MIC, TEC2010-14825/MIC, in part by the Consejería de Innovación, Ciencia y Empresa, under contract TIC-2532 and in part by the I Plan Propio de Docencia de la U. de Sevilla, LabCMA2010 project.Peer Reviewe
M[pi]log, Macromodeling via parametric identification of logic gates
This paper addresses the development of computational models of digital integrated circuit input and output buffers via the identification of nonlinear parametric models. The obtained models run in standard circuit simulation environments, offer improved accuracy and good numerical efficiency, and do not disclose information on the structure of the modeled devices. The paper reviews the basics of the parametric identification approach and illustrates its most recent extensions to handle temperature and supply voltage variations as well as power supply ports and tristate devices
Computational and Robotic Models of Early Language Development: A Review
We review computational and robotics models of early language learning and
development. We first explain why and how these models are used to understand
better how children learn language. We argue that they provide concrete
theories of language learning as a complex dynamic system, complementing
traditional methods in psychology and linguistics. We review different modeling
formalisms, grounded in techniques from machine learning and artificial
intelligence such as Bayesian and neural network approaches. We then discuss
their role in understanding several key mechanisms of language development:
cross-situational statistical learning, embodiment, situated social
interaction, intrinsically motivated learning, and cultural evolution. We
conclude by discussing future challenges for research, including modeling of
large-scale empirical data about language acquisition in real-world
environments.
Keywords: Early language learning, Computational and robotic models, machine
learning, development, embodiment, social interaction, intrinsic motivation,
self-organization, dynamical systems, complexity.Comment: to appear in International Handbook on Language Development, ed. J.
Horst and J. von Koss Torkildsen, Routledg
A neuromorphic systems approach to in-memory computing with non-ideal memristive devices: From mitigation to exploitation
Memristive devices represent a promising technology for building neuromorphic
electronic systems. In addition to their compactness and non-volatility
features, they are characterized by computationally relevant physical
properties, such as state-dependence, non-linear conductance changes, and
intrinsic variability in both their switching threshold and conductance values,
that make them ideal devices for emulating the bio-physics of real synapses. In
this paper we present a spiking neural network architecture that supports the
use of memristive devices as synaptic elements, and propose mixed-signal
analog-digital interfacing circuits which mitigate the effect of variability in
their conductance values and exploit their variability in the switching
threshold, for implementing stochastic learning. The effect of device
variability is mitigated by using pairs of memristive devices configured in a
complementary push-pull mechanism and interfaced to a current-mode normalizer
circuit. The stochastic learning mechanism is obtained by mapping the desired
change in synaptic weight into a corresponding switching probability that is
derived from the intrinsic stochastic behavior of memristive devices. We
demonstrate the features of the CMOS circuits and apply the architecture
proposed to a standard neural network hand-written digit classification
benchmark based on the MNIST data-set. We evaluate the performance of the
approach proposed on this benchmark using behavioral-level spiking neural
network simulation, showing both the effect of the reduction in conductance
variability produced by the current-mode normalizer circuit, and the increase
in performance as a function of the number of memristive devices used in each
synapse.Comment: 13 pages, 12 figures, accepted for Faraday Discussion
Analog VLSI-Based Modeling of the Primate Oculomotor System
One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real time using similar constraints. Analog very large-scale integrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing and fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built that simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brain stem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, and saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates
Variable-fidelity electromagnetic simulations and co-kriging for accurate modeling of antennas
Accurate and fast models are indispensable in contemporary antenna design. In this paper, we describe the low-cost antenna modeling methodology involving variable-fidelity electromagnetic (EM) simulations and co-Kriging. Our approach exploits sparsely sampled accurate (high-fidelity) EM data as well as densely sampled coarse-discretization (low-fidelity) EM simulations that are accommodated into one model using the co-Kriging technique. By using coarse-discretization simulations, the computational cost of creating the antenna model is greatly reduced compared to conventional approaches, where high-fidelity simulations are directly used to set up the model. At the same time, the modeling accuracy is not compromised. The proposed technique is demonstrated using three examples of antenna structures. Comparisons with conventional modeling based on high-fidelity data approximation, as well as applications for antenna design, are also discussed
Recommended from our members
Spring School on Language, Music, and Cognition: Organizing Events in Time
The interdisciplinary spring school “Language, music, and cognition: Organizing events in time” was held from February 26 to March 2, 2018 at the Institute of Musicology of the University of Cologne. Language, speech, and music as events in time were explored from different perspectives including evolutionary biology, social cognition, developmental psychology, cognitive neuroscience of speech, language, and communication, as well as computational and biological approaches to language and music. There were 10 lectures, 4 workshops, and 1 student poster session.
Overall, the spring school investigated language and music as neurocognitive systems and focused on a mechanistic approach exploring the neural substrates underlying musical, linguistic, social, and emotional processes and behaviors. In particular, researchers approached questions concerning cognitive processes, computational procedures, and neural mechanisms underlying the temporal organization of language and music, mainly from two perspectives: one was concerned with syntax or structural representations of language and music as neurocognitive systems (i.e., an intrapersonal perspective), while the other emphasized social interaction and emotions in their communicative function (i.e., an interpersonal perspective). The spring school not only acted as a platform for knowledge transfer and exchange but also generated a number of important research questions as challenges for future investigations
- …