1,235 research outputs found
Classification of grasping tasks based on EEG-EMG coherence
This work presents an innovative application of the well-known concept of
cortico-muscular coherence for the classification of various motor tasks, i.e.,
grasps of different kinds of objects. Our approach can classify objects with
different weights (motor-related features) and different surface frictions
(haptics-related features) with high accuracy (over 0:8). The outcomes
presented here provide information about the synchronization existing between
the brain and the muscles during specific activities; thus, this may represent
a new effective way to perform activity recognition
Automated routing and control of silicon photonic switch fabrics
Automatic reconfiguration and feedback controlled routing is demonstrated in an 8Ă—8 silicon photonic switch fabric based on Mach-Zehnder interferometers. The use of non-invasive Contactless Integrated Photonic Probes (CLIPPs) enables real-time monitoring of the state of each switching element individually. Local monitoring provides direct information on the routing path, allowing an easy sequential tuning and feedback controlled stabilization of the individual switching elements, thus making the switch fabric robust against thermal crosstalk, even in the absence of a cooling system for the silicon chip. Up to 24 CLIPPs are interrogated by a multichannel integrated ASIC wire-bonded to the photonic chip. Optical routing is demonstrated on simultaneous WDM input signals that are labelled directly on-chip by suitable pilot tones without affecting the quality of the signals. Neither preliminary circuit calibration nor lookup tables are required, being the proposed control scheme inherently insensible to channels power fluctuations
On-Chip OSNR Monitoring with Silicon Photonics Transparent Detector
Non-invasive integrated detectors, named contactless integrated photonic probe (CLIPP), are employed to demonstrate on-chip noise-independent power monitoring of optical channels and in-band optical signal to noise ratio (OSNR) measurement. The proposed technique is based on a two-step lock-in demodulation of optical signals that are suitably labeled with low-modulation-index labels. We demonstrate OSNR measurement from 8 up to 27 dB/0.1 nm on 10-Gb/s ON-OFF keying signals with a power level ranging from -25 up to -15 dBm. This approach provides a promising tool for the monitoring of channels in reconfigurable optical networks with flexible channel allocation strategy, where the small channel separation makes the measurement of the in-band OSNR challenging
Intervista a Leo Ortolani
Interview with Leo OrtolaniIntervista a Leo Ortolan
Bayesian modeling and clustering for spatio-temporal areal data: An application to Italian unemployment
Spatio-temporal areal data can be seen as a collection of time series which
are spatially correlated according to a specific neighboring structure.
Incorporating the temporal and spatial dimension into a statistical model poses
challenges regarding the underlying theoretical framework as well as the
implementation of efficient computational methods. We propose to include
spatio-temporal random effects using a conditional autoregressive prior, where
the temporal correlation is modeled through an autoregressive mean
decomposition and the spatial correlation by the precision matrix inheriting
the neighboring structure. Their joint distribution constitutes a Gaussian
Markov random field, whose sparse precision matrix enables the usage of
efficient sampling algorithms. We cluster the areal units using a nonparametric
prior, thereby learning latent partitions of the areal units. The performance
of the model is assessed via an application to study regional unemployment
patterns in Italy. When compared to other spatial and spatio-temporal
competitors, the proposed model shows more precise estimates and the additional
information obtained from the clustering allows for an extended economic
interpretation of the unemployment rates of the Italian provinces
Subatomic Proof Systems: Splittable Systems
This paper presents the first in a series of results that allow us to develop
a theory providing finer control over the complexity of normalisation, and in
particular of cut elimination. By considering atoms as self-dual
non-commutative connectives, we are able to classify a vast class of inference
rules in a uniform and very simple way. This allows us to define simple
conditions that are easily verifiable and that ensure normalisation and cut
elimination by way of a general theorem. In this paper we define and consider
splittable systems, which essentially comprise a large class of linear logics,
including MLL and BV, and we prove for them a splitting theorem, guaranteeing
cut elimination and other admissibility results as corollaries. In papers to
follow, we will extend this result to non-linear logics. The final outcome will
be a comprehensive theory giving a uniform treatment for most existing logics
and providing a blueprint for the design of future proof systems.Comment: 32 page
All-optical mode unscrambling on a silicon photonic chip
Propagation of light beams through scattering or multimode systems may lead
to randomization of the spatial coherence of the light. Although information is
not lost, its recovery requires a coherent interferometric reconstruction of
the original signals, which have been scrambled into the modes of the
scattering system. Here, we show that we can automatically unscramble four
optical beams that have been arbitrarily mixed in a multimode waveguide,
undoing the scattering and mixing between the spatial modes through a mesh of
silicon photonics Mach-Zehnder interferometers. Using embedded transparent
detectors and a progressive tuning algorithm, the mesh self-configures
automatically and reset itself after significantly perturbing the mixing,
without turning off the beams. We demonstrate the recovery of four separate 10
Gbits/s information channels, with residual cross-talk between beams of -20dB.
This principle of self-configuring and self-resetting in optical systems should
be applicable in a wide range of optical applications.Comment: 23 pages, 10 figure
Wavelength locking of silicon photonics multiplexer for DML-based WDM transmitter
We present a wavelength locking platform enabling the feedback control of silicon (Si) microring resonators (MRRs) for the realization of a 4 Ă— 10 Gb/s wavelength-division-multiplexing (WDM) transmitter. Four thermally tunable Si MRRs are employed to multiplex the signals generated by four directly modulated lasers (DMLs) operating in the L-band, as well as to improve the quality of the DMLs signals. Feedback control is achieved through a field-programmable gate array controller by monitoring the working point of each MRR through a transparent detector integrated inside the resonator. The feedback system provides an MRR wavelength stability of about 4 pm (0.5 GHz) with a time response of 60 ms. Bit error rate (BER) measurements confirm the effectiveness and the robustness of the locking system to counteract sensitivity degradations due to thermal drifts, even under uncooled operation conditions for the Si chip
Automated routing and control of silicon photonic switch fabrics
Automatic reconfiguration and feedback controlled routing is demonstrated in an 8Ă—8 silicon photonic switch fabric based on Mach-Zehnder interferometers. The use of non-invasive Contactless Integrated Photonic Probes (CLIPPs) enables realtime monitoring of the state of each switching element individually. Local monitoring provides direct information on the routing path, allowing an easy sequential tuning and feedback controlled stabilization of the individual switching elements, thus making the switch fabric robust against thermal crosstalk, even in the absence of a cooling system for the silicon chip. Up to 24 CLIPPs are interrogated by a multichannel integrated ASIC wirebonded to the photonic chip. Optical routing is demonstrated on simultaneous WDM input signals that are labelled directly on-chip by suitable pilot tones without affecting the quality of the signals. Neither preliminary circuit calibration nor lookup tables are required, being the proposed control scheme inherently insensible to channels power fluctuations
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