Kollia, Ilianna
Predicting Parkinson's Disease using Latent Information extracted from Deep Neural Networks
Kollia, Ilianna, Stafylopatis, Andreas-Georgios, Kollias, Stefanos
Predicting Parkinson's Disease using Latent Information extracted from Deep Neural Networks Abstract--This paper presents a new method for medical diagnosis of neurodegenerative diseases, such as Parkinson's, by extracting and using latent information from trained Deep convolutional, orconvolutional-recurrent Neural Networks (DNNs). In particular, our approach adopts a combination of transfer learning, k-means clustering and k-Nearest Neighbour classification ofdeep neural network learned representations to provide enriched prediction of the disease based on MRI and/or DaT Scan data. A new loss function is introduced and used in the training of the DNNs, so as to perform adaptation of the generated learned representations between data from different medical environments. Results are presented using a recently published database of Parkinson's related information, which was generated and evaluated in a hospital environment. Index Terms--latent variable information, deep convolutional and recurrent neural networks, transfer learning and domain adaptation, modified loss function, prediction, Parkinson's disease, MRI,DaT Scan data. I. INTRODUCTION Machine learning techniques have been largely used in medical signaland image analysis for prediction of neurodegenerative disorders,such as Alzheimer's and Parkinson's, which significantly affect elderly people, especially in developed countries [1], [2], [3].
Lower and Upper Bounds for SPARQL Queries over OWL Ontologies
Glimm, Birte (University of Ulm) | Kazakov, Yevgeny (University of Ulm) | Kollia, Ilianna (National Technical University of Athens) | Stamou, Giorgos (National Technical University of Athens)
The paper presents an approach for optimizing the evaluation of SPARQL queries over OWL ontologies using SPARQL's OWL Direct Semantics entailment regime. The approach is based on the computation of lower and upper bounds, but we allow for much more expressive queries than related approaches. In order to optimize the evaluation of possible query answers in the upper but not in the lower bound, we present a query extension approach that uses schema knowledge from the queried ontology to extend the query with additional parts. We show that the resulting query is equivalent to the original one and we use the additional parts that are simple to evaluate for restricting the bounds of subqueries of the initial query. In an empirical evaluation we show that the proposed query extension approach can lead to a significant decrease in the query execution time of up to four orders of magnitude.