Time filter

Source Type

Pham M.-D.,VU University Amsterdam | Passing L.,Technical University Monchen | Erling O.,OpenLink Software | Boncz P.,CWI
WWW 2015 - Proceedings of the 24th International Conference on World Wide Web | Year: 2015

We motivate and describe techniques that allow to detect an "emergent" relational schema from RDF data. We show that on a wide variety of datasets, the found structure explains well over 90% of the RDF triples. Further, we also describe technical solutions to the semantic challenge to give short names that humans find logical to these emergent tables, columns and relationships between tables. Our techniques can be exploited in many ways, e.g., to improve the efficiency of SPARQL systems, or to use existing SQL-based applications on top of any RDF dataset using a RDBMS. Source

Zvolsky M.,German Electron Synchrotron | Cserkaszky A.,SurgicEye GmbH | Cucciati G.,University of Milan Bicocca | Garutti E.,University of Hamburg | Frisch B.,Technical University Monchen
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014 | Year: 2014

The EndoTOFPET-US collaboration develops a novel multimodal device for Ultrasound (US) Endoscopy and Positron Emission Tomography (PET) for detecting and quantifying novel morphologic and functional biomarkers for pancreas and prostate oncology. The detector is based on scintillating crystals with Silicon Photomultiplier (SiPM) read-out, aiming at a time of flight coincidence time resolution of 200 ps and a spatial resolution of ≈ 1 mm to allow for more sensitive, more precise and lower radiation-dose imaging than whole-body devices. We develop a framework, which is built around the Geant4-based simulation toolkit GAMOS, to simulate and reconstruct realistic imaging scenarios with this asymmetric PET detector. Both attenuation and activity DICOM data from e.g. PET/CT scans can be incorporated as phantoms in the simulations. The framework takes care of distributing jobs on a computing grid which is crucial for running large-scale simulations on voxelised phantoms. A set of studies on simple simulated phantoms quantifies the influence of acquisition time and detector movement on the spatial image resolution and overall image quality. A scan time of approx. 10 min and small rotation of around 10° yields a sufficient image quality. We further present qualitative studies of the expected performance of the EndoTOFPET-US detector using voxelised patient PET/CT DICOM datasets. The studies suggest that the endoscopic approach is able to separate the prostatic lesion well from the background radiation from prostate and bladder. © 2014 IEEE. Source

Marsaux C.F.M.,Maastricht University | Celis-Morales C.,Institute of Cellular Medicine | Hoonhout J.,Philips | Claassen A.,Philips | And 19 more authors.
PLoS ONE | Year: 2016

Background Comparisons of objectively measured physical activity (PA) between residents of European countries measured concurrently with the same protocol are lacking. We aimed to compare PA between the seven European countries involved in the Food4Me Study, using accelerometer data collected remotely via the Internet. Methods Of the 1607 participants recruited, 1287 (539 men and 748 women) provided at least 3 weekdays and 2 weekend days of valid accelerometer data (TracmorD) at baseline and were included in the present analyses. Results Men were significantly more active than women (physical activity level = 1.74 vs. 1.70, p < 0.001). Time spent in light PA and moderate PA differed significantly between countries but only for women. Adherence to the World Health Organization recommendation to accumulate at least 150 min of moderate-equivalent PA weekly was similar between countries for men (range: 54-65%) but differed significantly between countries for women (range: 26- 49%). Prevalence estimates decreased substantially for men and women in all seven countries when PA guidelines were defined as achieving 30 min of moderate and vigorous PA per day. Conclusions We were able to obtain valid accelerometer data in real time via the Internet from 80% of participants. Although our estimates are higher compared with data from Sweden, Norway, Portugal and the US, there is room for improvement in PA for all countries involved in the Food4Me Study. © 2016 Marsaux et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Roehm H.,Robert Bosch GmbH | Oehlerking J.,Robert Bosch GmbH | Woehrle M.,Robert Bosch GmbH | Althoff M.,Technical University Monchen
HSCC 2016 - Proceedings of the 19th International Conference on Hybrid Systems: Computation and Control | Year: 2016

Industrial-sized hybrid systems are typically not amenable to formal veri-cation techniques. For this reason, a common approach is to formally verify abstractions of (parts of) the original system. However, we need to show that this abstrac-tion conforms to the actual system implementation including its physical dynamics. In particular, veri-ed properties of the abstract system need to transfer to the implementation. To this end, we introduce a formal conformance relation, called reachset conformance, which guarantees transference of safety properties, while being a weaker relation than the existing trace inclusion conformance. Based on this formal relation, we present a conformance testing method which allows us to tune the trade-off between accuracy and com-putational load. Additionally, we present a test selection algorithm that uses a coverage measure to reduce the num-ber of test cases for conformance testing. We experimentally show the benefits of our novel techniques based on an exam-ple from autonomous driving. © 2016 ACM. Source

Kolling C.,Bayerische Landesanstalt for Wald und Forstwirtschaft | Mette T.,Bayerische Landesanstalt for Wald und Forstwirtschaft | Knoke T.,Technical University Monchen
Schweizerische Zeitschrift fur Forstwesen | Year: 2016

Changes in climate conditions will lead to strong yet uncertain changes concerning forest growth and cultivation risk. Economic success as an important criterion for management decisions depends on both aspects, natural yield and risk. This study presents a new concept how (potential) yield and risk can be estimated from large-scale inventory data. As a result, any stand can be plotted in a yield-risk coordinate system and its future yield expectancy can be described by a trajectory in the yield-risk space. This strictly analytical approach cannot take over silvicultural decisions, but facilitates them from an objective basis. The implementation of approved economic guidelines such as the caution principle or the principle of flexibility builds upon the yield-risk approach and demonstrates benefits of climate-Adapted stable mixed forest silviculture. Source

Discover hidden collaborations