22 research outputs found
Real-time outlier detection for large datasets by RT-DetMCD
Modern industrial machines can generate gigabytes of data in seconds,
frequently pushing the boundaries of available computing power. Together with
the time criticality of industrial processing this presents a challenging
problem for any data analytics procedure. We focus on the deterministic minimum
covariance determinant method (DetMCD), which detects outliers by fitting a
robust covariance matrix. We construct a much faster version of DetMCD by
replacing its initial estimators by two new methods and incorporating
update-based concentration steps. The computation time is reduced further by
parallel computing, with a novel robust aggregation method to combine the
results from the threads. The speed and accuracy of the proposed real-time
DetMCD method (RT-DetMCD) are illustrated by simulation and a real industrial
application to food sorting
Real-time discriminant analysis in the presence of label and measurement noise
Quadratic discriminant analysis (QDA) is a widely used classification
technique. Based on a training dataset, each class in the data is characterized
by an estimate of its center and shape, which can then be used to assign unseen
observations to one of the classes. The traditional QDA rule relies on the
empirical mean and covariance matrix. Unfortunately, these estimators are
sensitive to label and measurement noise which often impairs the model's
predictive ability. Robust estimators of location and scatter are resistant to
this type of contamination. However, they have a prohibitive computational cost
for large scale industrial experiments. We present a novel QDA method based on
a recent real-time robust algorithm. We additionally integrate an anomaly
detection step to classify the most atypical observations into a separate class
of outliers. Finally, we introduce the label bias plot, a graphical display to
identify label and measurement noise in the training data. The performance of
the proposed approach is illustrated in a simulation study with huge datasets,
and on real datasets about diabetes and fruit
Wishful thinking? Kant over de moeizame verhouding tussen ethiek en politiek in Zum ewigen Frieden
status: publishe
Wishful thinking? Kant over de moeizame verhouding tussen ethiek en politiek in Zum ewigen Frieden
status: publishe
Eindverslag project aanmoedigingsfonds. Wijzer met de jaren. Optimalisering van de leeromgeving voor werkstudenten wijsbegeerte 2008-2009
nrpages: 128status: publishe
Eindverslag OOI project [2005/13]. Eigen-wijs: individuele training wijsgerige vaardigheden 2005-2007
nrpages: 57status: publishe
Electrical stimulation in the bed nucleus of the stria terminalis alleviates severe obsessive-compulsive disorder
In 1998, we proposed deep brain stimulation as a last-resort treatment option for patients suffering from severe, treatment-resistant obsessive-compulsive disorder (OCD). Here, 24 OCD patients were included in a long-term follow-up study to evaluate the effects of electrical stimulation in the anterior limbs of the internal capsule (ALIC) and bed nucleus of the stria terminalis (BST). We find that electrical stimulation in the ALIC/BST area is safe and significantly decreases obsessions, compulsions, and associated anxiety and depressive symptoms, and improves global functioning in a blinded crossover trial (n=17), after 4 years (n=18), and at last follow-up (up to 171 months, n=24). Moreover, our data indicate that BST may be a better stimulation target compared with ALIC to alleviate OCD symptoms. We conclude that electrical stimulation in BST is a promising therapeutic option for otherwise treatment-resistant OCD patients.status: publishe