Using Neural
Networks to Understand Autism
By Ira L. Cohen, Ph.D.
I'm a
psychologist studying children with autism and trying to better
understand, treat, and possibly help prevent this condition.
Studying neuroscience in graduate school, my post-doctoral work
was in clinical experimental psychology. While I don't consider
myself a neural networks expert, I probably know more about the
subject that most in my field - thanks in part to some excellent
NeuralWare courses I took quite a while ago.
When first using NeuralWorks Professional II/PLUS, back in 1994, I
published (in the Journal of Autism and Developmental Disorders)
an article about using neural networks as a way of classifying
children with autism and discriminating them from other groups. In
the process of so doing, we demonstrated that neural networks
technology was superior to discriminate analysis in classifying
the children. At that time, the field of diagnosing autism was
diffuse; since then, so-called "gold standard" methods of
diagnosing kids have been developed. While we can now reliably
diagnose autism using these tools, our ability to define
sub-groups is still problematic and we therefore continue to have
interest in using neural network classifiers to help in this area.
Some years later, I realized that, neural networks and autistic
children have something in common. They are both brilliant at some
tasks, and abysmal at others. In fact, in the mid 1990's, the
first good autopsy studies were coming out, showing that the
brains of autistic people develop differently - they had too few
neurons in some areas, and a much higher-than-average
concentration in others. I began to see analogies between the way
neural networks learn and the way autistic children learn. If you
give either too little or too much information, they perform
poorly. I used my copy of Professional II/PLUS to simulate
autistic behavior, intentionally sub-optimizing the input and the
design of the network. For example, I was varying the size of the
hidden layer, and giving the application more and more complex
problems in order to study rates of acquisition and rates of
generalization. The correlation between the difficulty that poorly
defined neural networks have with generalization and the
difficulty that children with autism have with generalization
proved to be eerily similar, and I published an article about the
correlation. This helped me to understand what's wrong with the
kids and why they learn the way they do. It also suggested ways of
intervening.
Read the rest of this article... |
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Message from the CEO
In this issue, our featured customer, Dr. Ira Cohen, offers a
very different perspective on using neural networks and NeuralWare
products in medical diagnostic contexts.
Also related to medical diagnostics, I am a co-author with
researchers from the Windber Research Institute in Johnstown
Pennsylvania, who have submitted a paper to the 2005 International
Conference on Natural Computation (ICNC'05) and the International
Conference on Fuzzy Systems and Knowledge Discovery (FSKD'05) that
will be held in Changsha China, in August. The paper describes a
preliminary modeling effort that is using NeuralWare technology to
determine the efficacy of circulating matrix metalloproteinases as
breast cancer predictive biomarkers. We look forward to continuing
to work with WRI in this important area.
As we were putting this issue together, Zhen Liu and I were also
preparing for another trip to Asia. In China, we will follow up
with potential partners for the crime analysis and forecasting
system and the television shopping system, and we will participate
in a technical meeting with engineers from Wuhan Iron and Steel,
our technology licensee, who are embarking on a significant new
project with Baosteel, the largest steel maker in China.
I will then travel to Japan, where I am making a presentation to
the HP User Group in Tokyo, arranged by our Japanese partner, SET
Software Co. Ltd. Also participating in the User Group will be
Duane Presti, of PARIS Technologies, whose PowerOLAP product will
soon be integrated with NeuralWare's neural network technology to
provide a new platform for business intelligence applications.
All in all, a busy month - but not too busy that we can't begin a
dialog with you - what can we help you discover?
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Tech Tips
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Choosing Datasets for Sensitivity Analysis
By Bob Everly
NeuralWorks Predict and NeuralWorks Professional II/PLUS
both include a sensitivity analysis feature. Sensitivity
analysis is used to determine the impact that each input field has
on a model (see
prior newsletter for background details).
Neural networks are most often created using various datasets,
usually a training dataset, a test dataset, and one
or more validation datasets. It is typical to build and
select models using the training and test subsets, and then
measure anticipated real-world performance using validation
datasets. So which of these datasets are the best for measuring a
model's input-to-output sensitivities (i.e., which input will have
the greatest effect on the output)?
I like to use all available data, so that I get the most
global picture possible, with the caveat that it is beneficial to
know the distribution of that data. Consider, for example, a
two-class dataset with target outputs of 0 and 1. (This same
discussion holds true for continuously-valued targets such as
predicting a temperature or sales volume, but it is easiest
understood when thinking of only two categories.) In our two-class
example, the training dataset is probably balanced such
that there's a somewhat equal number of 'class0' and 'class1' data
records. The test dataset is also probably balanced, but as
is typical, our validation dataset contains real-world
distributions.
Imagine that 90 percent of these validation data records are all
'class1'. When measuring statistical performance on that set, be
sure to look at each class separately, rather than use an
all-encompassing measure like R Correlation or RMS Error - or use
a measure like Average Classification Rate, which handles skewed
distributions. Likewise do not trust sensitivity analysis outputs
that are produced by a skewed dataset.
The ideal dataset, then, is a merging of all available data, but
with the data in a balanced form. |
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Read the rest of this tech tip... |
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Take the NeuralSight Challenge!
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We're throwing down the gauntlet! Send us your best model and
the data you used to create it. Using NeuralSight, we will attempt
to beat your results, proving NeuralSight's value. NeuralSight
works like a team of 100 modelers staying up all night testing
different neural network models and finding the best ones.
We can only accept a limited number of challenges, and we'll have
some specific requirements about the data you give us. If you
would like take the NeuralSight challenge, simply send email to
Bob Everly, and
he'll set it up. Good luck! |
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Have Your Modeling Story Published in Synapse
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If you would like to have your modeling story published in
Synapse, please send an email to
newsletter @neuralware.com
with a brief note about your application.
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The
professional's choice for predictive analytics
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With all the different tools out there, there is a reason
why NeuralWare is the professional's choice, used by most
Fortune 500 corporations and in companies and universities
all over the world. Call (412) 278-6292 or email
John Wavle
today to learn more about how we can help you with your
predictive modeling initiatives.
Learn More... |
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