TY - JOUR A1 - Lehmann, Matthias A1 - Wittpahl, Christian A1 - Zakour, Hatem Ben A1 - Braun, Alexander T1 - Modeling realistic optical aberrations to reuse existing drive scene recordings for autonomous driving validation JF - Journal of Electronic Imaging N2 - Training autonomous vehicles requires lots of driving sequences in all situations. Collecting and labeling these drive scenes is a very time-consuming and expensive process. Currently, it is not possible to reuse these drive scenes with different optical properties, because there exists no numerically efficient model for the transfer function of the optical system. We present a numerical model for the point spread function (PSF) of an optical system that can efficiently model both experimental measurements and lens design simulations of the PSF. The numerical basis for this model is a nonlinear regression of the PSF with an artificial neural network. The novelty lies in the portability and the parameterization of this model. We present a lens measurement series, yielding a numerical function for the PSF that depends only on the parameters defocus, field, and azimuth. By convolving existing images and videos with this PSF, we generate images as if seen through the measured lens. The methodology applies to any optical scenario, but we focus on the context of autonomous driving, where the quality of the detection algorithms depends directly on the optical quality of the used camera system. With this model, it is possible to reuse existing recordings, with the potential to avoid millions of test drive miles. The parameterization of the optical model allows for a method to validate the functional and safety limits of camera-based advanced driver assistance systems based on the real, measured lens actually used in the product. Y1 - 2019 U6 - https://doi.org/10.1117/1.JEI.28.1.013005 SN - 1560-229X VL - 28 IS - 1 SP - 013005 PB - SPIE ER - TY - JOUR A1 - Leadbetter, S. J. A1 - Hort, M. C. A1 - von Löwis, S. A1 - Weber, Konradin A1 - Witham, C. S. T1 - Modeling the resuspension of ash deposited during the eruption of Eyjafjallajökull in spring 2010 JF - Journal of Geophysical Research: Atmospheres N2 - Eyjafjallajökull, a volcano in southern Iceland, erupted explosively in April and May 2010 depositing ash over a region of more than 3000 km2 to the east and southeast of the volcano. This deposited ash has been frequently remobilized by the wind causing concern for the health of Icelanders living in the region. An investigation was carried out to determine whether it would be possible to produce forecasts of days when high airborne ash concentrations were likely to occur. Information about the spatially varying surface characteristics of the region of deposited ash is not available so in the modeling approach adopted here ash is released from the surface at a rate proportional to the cube of the excess friction velocity (local friction velocity minus a threshold) only when the friction velocity exceeds a threshold. Movement of the resuspended ash is then modeled in a Lagrangian dispersion model. Modeled ash concentrations are compared to observed concentrations from two periods; PM10 observations between 23 May and 2 July 2010 and airborne particle counts between 21 September 2010 and 16 February 2011. More than 66% of the resuspension episodes between May and July are captured by the model and the relative magnitudes of the modeled episodes in this period are in good agreement with the observations. 66% of episodes between October and February are also captured by the model although there is an increase in the false alarm rate which appears to be due to the influence of precipitation. KW - Luftreinhaltung Y1 - 2012 U6 - https://doi.org/10.1029/2011JD016802 SN - 0148-0227 VL - 117 IS - D20 PB - American Geophysical Union (AGU) ER - TY - JOUR A1 - Versümer, Siegbert A1 - Steffens, Jochen A1 - Blättermann, Patrick A1 - Becker-Schweitzer, Jörg T1 - Modelling evaluations of low-level sounds in everyday situations using linear machine learning for variable selection JF - Frontiers in Psychology KW - DOAJ Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-23779 SN - 1664-1078 N1 - Supplementary Material The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpsyg.2020.570761/full#supplementary-material VL - 11 PB - Frontiers ER - TY - JOUR A1 - Benim, Ali Cemal A1 - Epple, B. A1 - Krohmer, B. T1 - Modelling of pulverised coal combustion by a Eulerian-Eulerian two-phase flow formulation JF - Progress in Computational Fluid Dynamics, An International Journal Y1 - 2005 U6 - https://doi.org/10.1504/pcfd.2005.007067 VL - 5 IS - 6 PB - inderscience ER - TY - CHAP A1 - Jürjens, Jan A1 - Ochoa, Martín A1 - Schmidt, Holger A1 - Marchal, Loïc A1 - Houmb, Siv Hilde A1 - Islam, Shareeful ED - Bernardo, Marco ED - Issarny, Valérie T1 - Modelling Secure Systems Evolution: Abstract and Concrete Change Specifications T2 - Formal Methods for Eternal Networked Software Systems: 11th International School on Formal Methods for the Design of Computer, Communication and Software Systems, SFM 2011, Bertinoro, Italy, June 13-18, 2011. Advanced Lectures N2 - Developing security-critical systems is difficult, and there are many well-known examples of vulnerabilities exploited in practice. In fact, there has recently been a lot of work on methods, techniques, and tools to improve this situation already at the system specification and design. However, security-critical systems are increasingly long-living and undergo evolution throughout their lifetime. Therefore, a secure software development approach that supports maintaining the needed levels of security even through later software evolution is highly desirable. In this chapter, we recall the UMLsec approach to model-based security and discuss on tools and techniques to model and verify evolution of UMLsec models. KW - software evolution KW - UMLsec KW - UMLseCH KW - security Y1 - 2011 UR - https://link.springer.com/chapter/10.1007/978-3-642-21455-4_15 SN - 978-3-642-21455-4 U6 - https://doi.org/10.1007/978-3-642-21455-4_15 VL - LNCS, 6659 SP - 504 EP - 526 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Echternacht, David A1 - Stagge, Hanno A1 - Priebe, Jens A1 - Wiernes, Pablo Ezequiel A1 - Jagielski, Kai A1 - Petri, Anne-Kathrin A1 - Drießen, Sarah A1 - Trevisan, Bianka A1 - Digmayer, Claas A1 - Oberst, Christian A. A1 - Keysselitz, Bärbel A1 - Kremer, Martin A1 - Sieber, Sandra A1 - Krapp, Stefan A1 - Jakobs, Eva-Maria A1 - Frenz, Martin A1 - Lohrberg, Frank A1 - Wachten, Kunibert A1 - Moser, Albert T1 - Modelling, Planning, Design and Evaluation of DC-Distribution Grids T2 - International ETG Congress 2015 : die Energiewende ; blueprints for the new energy age ; proceedings ; November 17 - 18, 2015, World Conference Center, Bonn Y1 - 2015 UR - http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7388494 SP - 289 EP - 295 PB - VDE-Verl. CY - Bonn ER - TY - GEN A1 - Mehlhorn, Nils T1 - Modern Cross-Platform Development for Mobile Applications N2 - While developing for multiple platforms at once seems like a convenient solution, there are several challenges arising when trying to abstract the entire mobile development. This paper is meant to evaluate current cross-platform development for mobile applications. The background for its necessity, its conceptual approach and the problems to face when developing cross-platform were determined and explained in detail. Afterwards, certain solutions were evaluated against the former insights. Based on the results, an informed discussion and conclusion was performed. The mobile environment consist of only two big players by now, Android and iOS. These operating systems differ in architecture, design and consequently in the way applications are developed for each of them. Therefore, high demands are made towards cross-platform solutions. Tools which allow for the creation of applications for multiple platforms at once have to match native applications in regard to user experience and performance. At the same time they need to be able to optimize developments with the goal of being cost efficient. Apache Cordova, Xamarin and NativeScript were selected for evaluation in regard to their ability to meet these requirements. Cordova acts as the comparison group of cross-platform tools. It is the big player in the field and there are reasons for this. However, aspiring solutions with higher nativity and ambitious approaches are emerging. Xamarin and NativeScript deliver top quality results while offering loosely coupled developments. Therefore it is possible to develop high quality applications and still benefit from the advantages of platform-independent solutions. As a consequence mobile development is about to change in the foreseeable future. More sophisticated approaches may lead to a higher number of developments done cross-platform, and rightfully so. KW - cross-plattform KW - mobile KW - Entwicklung KW - cross-platform KW - mobile KW - development KW - M Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-11276 CY - Düsseldorf ER - TY - CHAP A1 - Hurd, Paul A1 - Truckenmueller, Frank A1 - Thamm, Norbert A1 - Pollak, Helmut A1 - Neef, Matthias A1 - Deckers, Mathias T1 - Modern Reaction HP/IP Turbine Technology Advances and Experiences T2 - Proceedings of the ASME Power Conference - 2005 : includes papers from the 2005 International Conference on Power Engineering (ICOPE) ; presented at the 2005 ASME Power Conference, April 5 - 7, 2005, Chicago, Illinois, USA Y1 - 2005 UR - https://asmedigitalcollection.asme.org/POWER/proceedings/POWER2005/41820/425/311927 SN - 0-7918-4182-0 U6 - https://doi.org/10.1115/PWR2005-50085 SP - 425 EP - 435 PB - ASME CY - New York ER - TY - JOUR A1 - Elíasson, Jónas A1 - Palsson, Asgeir A1 - Weber, Konradin T1 - Monitoring ash clouds for aviation JF - Nature KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1038/475455b VL - 475 IS - 7357 PB - Springer Nature ER - TY - JOUR A1 - Galban, Craig A1 - Maderwald, Stefan A1 - Eggebrecht, Holger A1 - Grote, Wolfgang A1 - de Greiff, A. A1 - Uffmann, K. A1 - Ladd, M. E. T1 - Monitoring the Effects of Chronic Obstructive Pulmonary Disease on Muscle Elasticity by MR Elastography JF - Proc. Intl. Soc. Mag. Reson. Med. N2 - Men afflicted with chronic obstructive pulmonary disease (COPD) show signs of muscle dysfunction, such as increased muscle fatigue and acidosis during exercise. We hypothesize that muscle elasticity of the lower extremities differs between patients with COPD and age-related controls. The shear modulus of the soleus muscle was measured non-invasively using MR elastography (MRE) at 0%, 5%, 10%, 15%, and 20% of the subject’s maximum applied force. The results from this study showed statistical differences between the patients and controls, even though there were no statistical differences in the maximum applied force. Y1 - 2005 UR - https://cds.ismrm.org/protected/05MProceedings/PDFfiles/02015.pdf VL - 13 SP - 2015 ER - TY - JOUR A1 - Agnese, Pablo A1 - Salvador, Pablo F. T1 - More alike than different: the Spanish and Irish labour markets before and after the crisis JF - IZA Journal of European Labor Studies KW - DOAJ Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-28185 SN - 2193-9012 VL - 1 IS - 1 PB - Springer Nature ER - TY - CHAP A1 - Müller, Dennis A1 - Meuter, Mirko A1 - Park, Su-Birm T1 - Motion segmentation using interest points T2 - 2008 IEEE Intelligent Vehicles Symposium Y1 - 2008 SN - 978-1-4244-2568-6 U6 - https://doi.org/10.1109/IVS.2008.4621239 SP - 19 EP - 24 PB - IEEE ER - TY - CHAP A1 - Ladwig, Philipp A1 - Evers, Kester A1 - Jansen, Eric J. A1 - Fischer, Ben A1 - Nowottnik, David A1 - Geiger, Christian T1 - MotionHub: Middleware for Unification of Multiple Body Tracking Systems T2 - Proceedings of the 7th International Conference on Movement and Computing: MOCO '20: 7th International Conference on Movement and Computing, Jersey City, 15.07.2020-17.07.2020 Y1 - 2020 UR - https://dl.acm.org/doi/proceedings/10.1145/3401956 SN - 9781450375054 U6 - https://doi.org/10.1145/3401956.3404185 SP - 1 EP - 8 PB - ACM CY - New York ER - TY - CHAP A1 - Dahm, Markus T1 - MP3ergo - Usability of MP3 players T2 - proc. 10th intl conf Humans and Computers, Duesseldorf N2 - Listening to music played by small MP3-players is almost as ubiquituous as talking over mobile phones. In this paper we analyse interaction elements and usabilty of current MP3-players. To determine the usability, an empirical study based on a website that presented three simulated MP3-players was performed with over 1000 participants. The results show that, despite most marketing claims, some interaction devices are not as intuitive and really suitable for the task as they schould be. Also we found some surprising results concerning erroneous usage of navigation keys. KW - MP3 KW - usability Y1 - 2007 SP - 123 EP - 128 CY - Düsseldorf ER - TY - JOUR A1 - Huber, Florian A1 - van der Burg, Sven A1 - van der Hooft, Justin J. J. A1 - Ridder, Lars T1 - MS2DeepScore: a novel deep learning similarity measure to compare tandem mass spectra JF - Journal of Cheminformatics N2 - Mass spectrometry data is one of the key sources of information in many workflows in medicine and across the life sciences. Mass fragmentation spectra are generally considered to be characteristic signatures of the chemical compound they originate from, yet the chemical structure itself usually cannot be easily deduced from the spectrum. Often, spectral similarity measures are used as a proxy for structural similarity but this approach is strongly limited by a generally poor correlation between both metrics. Here, we propose MS2DeepScore: a novel Siamese neural network to predict the structural similarity between two chemical structures solely based on their MS/MS fragmentation spectra. Using a cleaned dataset of > 100,000 mass spectra of about 15,000 unique known compounds, we trained MS2DeepScore to predict structural similarity scores for spectrum pairs with high accuracy. In addition, sampling different model varieties through Monte-Carlo Dropout is used to further improve the predictions and assess the model's prediction uncertainty. On 3600 spectra of 500 unseen compounds, MS2DeepScore is able to identify highly-reliable structural matches and to predict Tanimoto scores for pairs of molecules based on their fragment spectra with a root mean squared error of about 0.15. Furthermore, the prediction uncertainty estimate can be used to select a subset of predictions with a root mean squared error of about 0.1. Furthermore, we demonstrate that MS2DeepScore outperforms classical spectral similarity measures in retrieving chemically related compound pairs from large mass spectral datasets, thereby illustrating its potential for spectral library matching. Finally, MS2DeepScore can also be used to create chemically meaningful mass spectral embeddings that could be used to cluster large numbers of spectra. Added to the recently introduced unsupervised Spec2Vec metric, we believe that machine learning-supported mass spectral similarity measures have great potential for a range of metabolomics data processing pipelines. KW - DOAJ Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-34847 UR - http://www.ncbi.nlm.nih.gov/pubmed/34715914 SN - 1758-2946 N1 - J.J.J.v.d.H. acknowledges funding from an ASDI eScience grant, ASDI.2017.030, from the Netherlands eScience Center. VL - 13 IS - 1 PB - Cold Spring Harbor Laboratory ER - TY - JOUR A1 - de Jonge, Niek F. A1 - Louwen, Joris J. R. A1 - Chekmeneva, Elena A1 - Camuzeaux, Stephane A1 - Vermeir, Femke J. A1 - Jansen, Robert S. A1 - Huber, Florian A1 - van der Hooft, Justin J. J. T1 - MS2Query: reliable and scalable MS2 mass spectra-based analogue search JF - Nature Communications N2 - Metabolomics-driven discoveries of biological samples remain hampered by the grand challenge of metabolite annotation and identification. Only few metabolites have an annotated spectrum in spectral libraries; hence, searching only for exact library matches generally returns a few hits. An attractive alternative is searching for so-called analogues as a starting point for structural annotations; analogues are library molecules which are not exact matches but display a high chemical similarity. However, current analogue search implementations are not yet very reliable and relatively slow. Here, we present MS2Query, a machine learning-based tool that integrates mass spectral embedding-based chemical similarity predictors (Spec2Vec and MS2Deepscore) as well as detected precursor masses to rank potential analogues and exact matches. Benchmarking MS2Query on reference mass spectra and experimental case studies demonstrate improved reliability and scalability. Thereby, MS2Query offers exciting opportunities to further increase the annotation rate of metabolomics profiles of complex metabolite mixtures and to discover new biology. KW - Metabolomik KW - Massenspektrometrie KW - Maschinelles Lernen KW - Reproduzierbarkeit KW - Metabolomics KW - Mass Spectrometry KW - Machine Learning KW - Complex Mixtures Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-46105 SN - 2041-1723 VL - 14 PB - Springer ER - TY - JOUR A1 - Müller, Patrick A1 - Braun, Alexander T1 - MTF as a performance indicator for AI algorithms? JF - Electronic Imaging: Society for Imaging Science and Technology N2 - Abstract The modulation-transfer function (MTF) is a fundamental optical metric to measure the optical quality of an imaging system. In the automotive industry it is used to qualify camera systems for ADAS/AD. Each modern ADAS/AD system includes evaluation algorithms for environment perception and decision making that are based on AI/ML methods and neural networks. The performance of these AI algorithms is measured by established metrics like Average Precision (AP) or precision-recall-curves. In this article we research the robustness of the link between the optical quality metric and the AI performance metric. A series of numerical experiments were performed with object detection and instance segmentation algorithms (cars, pedestrians) evaluated on image databases with varying optical quality. We demonstrate with these that for strong optical aberrations a distinct performance loss is apparent, but that for subtle optical quality differences – as might arise during production tolerances – this link does not exhibit a satisfactory correlation. This calls into question how reliable the current industry practice is where a produced camera is tested end-of-line (EOL) with the MTF, and fixed MTF thresholds are used to qualify the performance of the camera-under-test. KW - AI performance metrics KW - Artificial Intelligence KW - Modulation Transfer Function (MTF) KW - Optical Quality KW - Perception Y1 - 2023 U6 - https://doi.org/10.2352/EI.2023.35.16.AVM-125 SN - 2470-1173 VL - 35 IS - 16 SP - 1 EP - 7 PB - Society for Imaging Science and Technology ER - TY - THES A1 - Spiegel, Thomas T1 - Multi-criteria flexibility allocation for electric distribution networks N2 - Germany’s national climate protection policy, the German Energy Transition, is oriented towards the reduction of energy-related greenhouse gas emissions by rapidly expanding the share of renewable energy systems. New challenges arise regarding technical and energy economical integration as installed wind and photovoltaic power capacities increase continuously. This thesis contributes to the topic by introducing a framework for online multi-criteria flexibility allocation in electrical distribution networks with transport capacity limitations. It considers technical aspects and market participant interests that may contradict each other. Local master data is preprocessed using geospatial information of buildings, photovoltaic systems, wind turbines, and the human population within a spatial domain of interest. By combining weather forecast data, this establishes the foundation for predicting power flow in the electrical distribution network and generating grid-beneficial criteria utilizing the smart grid traff. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:579-opus-1011990 PB - IRC-Library, Information Resource Center der Constructor University CY - Bremen ER - TY - JOUR A1 - Zander, Nils A1 - Ruess, Martin A1 - Bog, Tino A1 - Kollmannsberger, Stefan A1 - Rank, Ernst T1 - Multi-level hp -adaptivity for cohesive fracture modeling JF - International Journal for Numerical Methods in Engineering Y1 - 2017 U6 - https://doi.org/10.1002/nme.5340 SN - 1097-0207 VL - 109 IS - 13 SP - 1723 EP - 1755 PB - Wiley ER - TY - JOUR A1 - Elhaddad, Mohamed A1 - Zander, Nils A1 - Bog, Tino A1 - Kudela, László A1 - Kollmannsberger, Stefan A1 - Kirschke, Jan A1 - Baum, Thomas A1 - Ruess, Martin A1 - Rank, Ernst T1 - Multi-level hp-finite cell method for embedded interface problems with application in biomechanics JF - International Journal for Numerical Methods in Biomedical Engineering N2 - This work presents a numerical discretization technique for solving 3-dimensional material interface problems involving complex geometry without conforming mesh generation. The finite cell method (FCM), which is a high-order fictitious domain approach, is used for the numerical approximation of the solution without a boundary-conforming mesh. Weak discontinuities at material interfaces are resolved by using separate FCM meshes for each material sub-domain and weakly enforcing the interface conditions between the different meshes. Additionally, a recently developed hierarchical hp-refinement scheme is used to locally refine the FCM meshes to resolve singularities and local solution features at the interfaces. Thereby, higher convergence rates are achievable for nonsmooth problems. A series of numerical experiments with 2- and 3-dimensional benchmark problems is presented, showing that the proposed hp-refinement scheme in conjunction with the weak enforcement of the interface conditions leads to a significant improvement of the convergence rates, even in the presence of singularities. Finally, the proposed technique is applied to simulate a vertebra-implant model. The application showcases the method's potential as an accurate simulation tool for biomechanical problems involving complex geometry, and it demonstrates its flexibility in dealing with different types of geometric description. Y1 - 2018 UR - http://www.ncbi.nlm.nih.gov/pubmed/29265715 U6 - https://doi.org/10.1002/cnm.2951 SN - 2040-7947 VL - 34 IS - 4 PB - Wiley ER -