337 research outputs found
Sub-Band Knowledge Distillation Framework for Speech Enhancement
In single-channel speech enhancement, methods based on full-band spectral
features have been widely studied. However, only a few methods pay attention to
non-full-band spectral features. In this paper, we explore a knowledge
distillation framework based on sub-band spectral mapping for single-channel
speech enhancement. Specifically, we divide the full frequency band into
multiple sub-bands and pre-train an elite-level sub-band enhancement model
(teacher model) for each sub-band. These teacher models are dedicated to
processing their own sub-bands. Next, under the teacher models' guidance, we
train a general sub-band enhancement model (student model) that works for all
sub-bands. Without increasing the number of model parameters and computational
complexity, the student model's performance is further improved. To evaluate
our proposed method, we conducted a large number of experiments on an
open-source data set. The final experimental results show that the guidance
from the elite-level teacher models dramatically improves the student model's
performance, which exceeds the full-band model by employing fewer parameters.Comment: Published in Interspeech 202
A Compact Monopole Antenna With Filtering Response for WLAN Applications
A novel compact monopole antenna with filtering response for WLAN applications is presented in this paper. The antenna is composed of a capacity-loaded matching patch, two resonators, and two end-coupled monopoles. The resonators consist of wide rectangular patches and narrow shorted lines to form the resonance, and the resonators are printed on the different layers to increase the design flexibility. Two meandering monopoles are located at the edges of the top layer with capacitive coupling at each other's end. The mutual couplings between the meander monopoles are utilized to produce two radiation nulls at the two band-edges. Based on the design method, the prototype of the proposed antenna was designed, fabricated and measured. The measured results show that the antenna has a broad bandwidth of 16% for S 11 <; -10 dB. Also, ideal omnidirectional radiation patterns, and steep band-edge selectivity with two radiation nulls are achieved for the proposed antenna
A Wideband Series-Fed Circularly Polarized Differential Antenna by Using Crossed Open Slot-Pairs
A novel method of designing a wideband series-fed circularly polarized (CP) differential antenna by using crossed open slot-pairs is presented in this paper. The near-field distributions and input impedance analyses show that the closely spaced open slot-pairs can radiate as the crossed dipoles and have stable radiating resistance with a compact radiator size. Besides, a wideband half-power phase shifter by using open slot is proposed and utilized to realize CP radiation. The proposed CP antenna is composed of a wide slot-pair and a narrow slot-pair. In the antenna design, the narrow slot-pair is not only excited as a radiator, but also elaborately loaded to provide wideband half-power output and quadrature phase excitation to the wide slot-pair. Both the proposed half-power phase shifter and CP antenna are illustrated by the corresponding equivalent circuits. Based on these analyses, the proposed antenna is designed, fabricated and measured. Compared to the simulated traditionally designed counterpart, 2.1 times wider axial ratio bandwidth is achieved for the proposed antenna. The measured overlapped bandwidth for axial ratio 10 dB is 1.95-3.45 GHz (55.6%). Also, the antenna gain and radiation patterns are measured, which agree well with the simulated results
A Dual-Polarized Planar Antenna Array Differentially-Fed by Orthomode Transducer
This paper presents a new design of a differentially-fed substrate integrated planar antenna array with dual-polarization. Compared with the traditional dual-polarized antenna arrays, the proposed array antenna has the advantages of simple configuration, high cross-polarization discrimination (XPD) and high gain. 2Ă2-element subarray design with a vialoaded crossover structure is used, which reduces the complexity of the array antenna. The operation bandwidth is improved by generating three resonances in the subarray. One 8Ă8 antenna array is designed, prototyped and tested to exemplify its potential applications in large dual-polarized antenna arrays. A planar orthomode transducer is used to achieve differential excitation for the antenna array. The measured results show that the proposed antenna array has an impedance bandwidth of 19.2â20.7 GHz for |S11| < â10 dB and port isolation higher than 20 dB. The array antenna exhibits a high XPD of 43 dB and a flat gain about 22.2 dBi within the bandwidth
A Low Complexity 16 X 16 Butler Matrix Design Using Eight-Port Hybrids
Beamforming networks such as Butler Matrices are important for multibeam array antenna applications. The challenge for Butler Matrix design is that their complexity increases with the number of ports. In this paper, a novel approach of designing a 16 X 16 Butler Matrix with significant structure simplification is presented. The eight-port hybrids with no crossovers are used to simplify the network. To ensure the network has the same magnitude and phase responses as the standard one, the location and phase shifting value of each fixed phase shifter are derived from the -matrix of each hybrid. A Butler Matrix network operating from 9 GHzâ11 GHz is designed to validate this concept. The compensated microstrip 3-dB/90° directional coupler, the phase shifter with a shunt open-and-short stub and the crossover with a resonating patch are used to reduce the transmission loss and enable broadband operation
Expanding Transportation Opportunities on Hawai`I Island
Residents
of
Hawai`i
Island
pay
some
of
the
highest
rates
for
electricity
and
petroleum
products
among
residents
of
the
United
States.
Moreover,
the
islands
of
the
Hawaiian
archipelago
rely
almost
entirely
on
imported
petroleum
fuels
for
both
transportation
and
energy
generation.
Though
Hawai`i
Island
has
integrated
more
renewable
energy
onto
its
electrical
grid
than
anywhere
else
in
the
U.S.,
the
reliance
on
fossil
fuel
remains
high
because
more
than
half
the
energy
demand
of
the
island
can
be
attributed
to
transportation.
Traditionally
mass
transit
systems
can
be
used
to
increase
energy
efficiency,
as
well
as
energy
sustainability
of
a
transportation
system;
as
a
result
the
University
of
Michigan
team
was
engaged
by
The
Kohala
Center
to
examine
and
analyze
the
public
transit
system
of
Hawai`i
Island
for
potential
improvements.
The
primary
objective
of
the
project
is
to
develop
a
set
of
recommendations
for
the
County
of
Hawai`i
focused
on
high-Ââimpact
solutions
to
reduce
fossil
fuel
use
in
the
islandâs
ground
transportation
system,
while
improving
accessibility
and
lowering
travel
times
for
commuters.
Our
team
completed
initial
research
to
gain
a
background
on
Hawai`i
and
its
energy
and
transit
challenges,
completed
data
collection
and
analysis
through
a
research
trip
to
Hawai`i,
and
designed
a
set
of
recommendations
for
optimizing
the
current
system,
as
well
as
potential
alternatives
that
include
the
establishment
of
carpooling
and
ride-Ââsharing
networks
that
would
employ
new
business
models
to
help
solve
some
additional
transit
issues.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/106554/1/Hawaii Transit_Final_for distribution_2014.pd
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