18,241 research outputs found
Theoretical investigation of the quantum noise in ghost imaging
Ghost imaging is a method to nonlocally image an object by transmitting pairs
of entangled photons through the object and a reference optical system
respectively. We present a theoretical analysis of the quantum noise in this
imaging technique. The dependence of the noise on the properties of the
apertures in the imaging system are discussed and demonstrated with a numerical
example. For a given source, the resolution and the signal-to-noise ratio
cannot be improved at the same time
Parameter Estimation of Switched Hammerstein Systems
This paper deals with the parameter estimation problem of the
Single-Input-Single-Output (SISO) switched Hammerstein system. Suppose that the
switching law is arbitrary but can be observed online. All subsystems are
parameterized and the Recursive Least Squares (RLS) algorithm is applied to
estimate their parameters. To overcome the difficulty caused by coupling of
data from different subsystems, the concept "intrinsic switch" is introduced.
Two cases are considered: i) The input is taken to be a sequence of independent
identically distributed (i.i.d.) random variables when identification is the
only purpose; ii) A diminishingly excited signal is superimposed on the control
when the adaptive control law is given. The strong consistency of the estimates
in both cases is established and a simulation example is given to verify the
theoretical analysis.Comment: 16 pages, 3 figures; Accepted for publication by Acta Mathematicae
Applicatae Sinica (http://link.springer.com/journal/10255
Scaling Speech Enhancement in Unseen Environments with Noise Embeddings
We address the problem of speech enhancement generalisation to unseen
environments by performing two manipulations. First, we embed an additional
recording from the environment alone, and use this embedding to alter
activations in the main enhancement subnetwork. Second, we scale the number of
noise environments present at training time to 16,784 different environments.
Experiment results show that both manipulations reduce word error rates of a
pretrained speech recognition system and improve enhancement quality according
to a number of performance measures. Specifically, our best model reduces the
word error rate from 34.04% on noisy speech to 15.46% on the enhanced speech.
Enhanced audio samples can be found in
https://speechenhancement.page.link/samples
Binary Nonlinearization of the Super Akns System Under an Implicit Symmetry Constraint
For the super AKNS system, an implicit symmetry constraint between the
potentials and the eigenfunctions is proposed. After introducing some new
variables to explicitly express potentials, the super AKNS system is decomposed
into two compatible finite-dimensional super systems (x-part and -part).
Furthermore, we show that the obtained super systems are integrable super
Hamiltonian systems in supersymmetry manifold .Comment: 10 pages, 5 figures, to appear in Journal of Physics
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