5,223 research outputs found
Quantum learning: optimal classification of qubit states
Pattern recognition is a central topic in Learning Theory with numerous
applications such as voice and text recognition, image analysis, computer
diagnosis. The statistical set-up in classification is the following: we are
given an i.i.d. training set where
represents a feature and is a label attached to that
feature. The underlying joint distribution of is unknown, but we can
learn about it from the training set and we aim at devising low error
classifiers used to predict the label of new incoming features.
Here we solve a quantum analogue of this problem, namely the classification
of two arbitrary unknown qubit states. Given a number of `training' copies from
each of the states, we would like to `learn' about them by performing a
measurement on the training set. The outcome is then used to design mesurements
for the classification of future systems with unknown labels. We find the
asymptotically optimal classification strategy and show that typically, it
performs strictly better than a plug-in strategy based on state estimation.
The figure of merit is the excess risk which is the difference between the
probability of error and the probability of error of the optimal measurement
when the states are known, that is the Helstrom measurement. We show that the
excess risk has rate and compute the exact constant of the rate.Comment: 24 pages, 4 figure
Generative Adversarial Networks for Mitigating Biases in Machine Learning Systems
In this paper, we propose a new framework for mitigating biases in machine
learning systems. The problem of the existing mitigation approaches is that
they are model-oriented in the sense that they focus on tuning the training
algorithms to produce fair results, while overlooking the fact that the
training data can itself be the main reason for biased outcomes. Technically
speaking, two essential limitations can be found in such model-based
approaches: 1) the mitigation cannot be achieved without degrading the accuracy
of the machine learning models, and 2) when the data used for training are
largely biased, the training time automatically increases so as to find
suitable learning parameters that help produce fair results. To address these
shortcomings, we propose in this work a new framework that can largely mitigate
the biases and discriminations in machine learning systems while at the same
time enhancing the prediction accuracy of these systems. The proposed framework
is based on conditional Generative Adversarial Networks (cGANs), which are used
to generate new synthetic fair data with selective properties from the original
data. We also propose a framework for analyzing data biases, which is important
for understanding the amount and type of data that need to be synthetically
sampled and labeled for each population group. Experimental results show that
the proposed solution can efficiently mitigate different types of biases, while
at the same time enhancing the prediction accuracy of the underlying machine
learning model
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