TY - JOUR A1 - Engelhardt, Lucas A1 - Melzner, Maximilian A1 - Havelkova, Linda A1 - Fiala, Pavel A1 - Christen, Patrik A1 - Dendorfer, Sebastian A1 - Simon, Ulrich T1 - A new musculoskeletal AnyBodyTM detailed hand model JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - Musculoskeletal research questions regarding the prevention or rehabilitation of the hand can be addressed using inverse dynamics simulations when experiments are not possible. To date, no complete human hand model implemented in a holistic human body model has been fully developed. The aim of this work was to develop, implement, and validate a fully detailed hand model using the AnyBody Modelling System (AMS) (AnyBody, Aalborg, Denmark). To achieve this, a consistent multiple cadaver dataset, including all extrinsic and intrinsic muscles, served as a basis. Various obstacle methods were implemented to obtain with the correct alignment of the muscle paths together with the full range of motion of the fingers. These included tori, cylinders, and spherical ellipsoids. The origin points of the lumbrical muscles within the tendon of the flexor digitorum profundus added a unique feature to the model. Furthermore, the possibility of an entire patient-specific scaling based on the hand length and width were implemented in the model. For model validation, experimental datasets from the literature were used, which included the comparison of numerically calculated moment arms of the wrist, thumb, and index finger muscles. In general, the results displayed good comparability of the model and experimental data. However, the extrinsic muscles showed higher accordance than the intrinsic ones. Nevertheless, the results showed, that the proposed developed inverse dynamics hand model offers opportunities in a broad field of applications, where the muscles and joint forces of the forearm play a crucial role. KW - Musculoskeletal KW - hand KW - AnyBody KW - inverse dynamics KW - moment arm Y1 - 2020 U6 - https://doi.org/10.1080/10255842.2020.1851367 VL - 24 IS - 7 SP - 777 EP - 787 PB - Taylor & Francis ER - TY - JOUR A1 - Chavez, Jhohan A1 - Böhm, Valter A1 - Becker, Tatiana I. A1 - Gast, Simon A1 - Zeidis, Igor A1 - Zimmermann, Klaus T1 - Actuators based on a controlled particle-matrix interaction in magnetic hybrid materials for applications in locomotion and manipulation systems JF - Physical Sciences Reviews N2 - The paper deals with the investigation of magneto-sensitive elastomers (MSE) and their application in technical actuator systems. MSE consist of an elastic matrix containing suspended magnetically soft and/or hard particles. Additionally, they can also contain silicone oil, graphite particles, thermoplastic components, etc., in various concentrations in order to tune specific properties such as viscosity, conductivity and thermoelasticity, respectively. The focuses of investigations are the beneficial properties of MSE in prototypes for locomotion and manipulation purposes that possess an integrated sensor function. The research follows the principle of a model-based design, i.e. the working steps are ideation, mathematical modelling, material characterization as well as building first functional models (prototypes). The developed apedal (without legs) and non-wheeled locomotion systems use the interplay between material deformations and the mechanical motion in connection with the issues of control and stability. Non-linear friction phenomena lead to a monotonous forward motion of the systems. The aim of this study is the design of such mechanical structures, which reduce the control costs. The investigations deal with the movement and control of ‘intelligent’ mechanisms, for which the magnetically field-controlled particle-matrix interactions provide an appropriate approach. The presented grippers enclose partially gripped objects, which is an advantage for handling sensitive objects. Form-fit grippers with adaptable contour at the contact area enable a uniform pressure distribution on the surface of gripped objects. Furthermore, with the possibility of active shape adaptation, objects with significantly differing geometries can be gripped. To realise the desired active shape adaptation, the effect of field-induced plasticity of MSE is used. The first developed prototypes mainly confirm the functional principles as such without direct application. For this, besides the ability of locomotion and manipulation itself, further technological possibilities have to be added to the systems. The first steps are therefore being taken towards integrated MSE based adaptive sensor systems. KW - apedal locomotion systems KW - field-controlled particle-matrix interaction KW - field-induced plasticity KW - form-fit gripper KW - integrated sensor-actuator systems KW - magneto-sensitive elastomer Y1 - 2020 U6 - https://doi.org/10.1515/psr-2019-0087 VL - 7 IS - 11 SP - 1263 EP - 1290 PB - de Gruyter ER - TY - JOUR A1 - De Souza Jr., Luis Antonio A1 - Passos, Leandro A. A1 - Mendel, Robert A1 - Ebigbo, Alanna A1 - Probst, Andreas A1 - Messmann, Helmut A1 - Palm, Christoph A1 - Papa, João Paulo T1 - Assisting Barrett's esophagus identification using endoscopic data augmentation based on Generative Adversarial Networks JF - Computers in Biology and Medicine N2 - Barrett's esophagus figured a swift rise in the number of cases in the past years. Although traditional diagnosis methods offered a vital role in early-stage treatment, they are generally time- and resource-consuming. In this context, computer-aided approaches for automatic diagnosis emerged in the literature since early detection is intrinsically related to remission probabilities. However, they still suffer from drawbacks because of the lack of available data for machine learning purposes, thus implying reduced recognition rates. This work introduces Generative Adversarial Networks to generate high-quality endoscopic images, thereby identifying Barrett's esophagus and adenocarcinoma more precisely. Further, Convolution Neural Networks are used for feature extraction and classification purposes. The proposed approach is validated over two datasets of endoscopic images, with the experiments conducted over the full and patch-split images. The application of Deep Convolutional Generative Adversarial Networks for the data augmentation step and LeNet-5 and AlexNet for the classification step allowed us to validate the proposed methodology over an extensive set of datasets (based on original and augmented sets), reaching results of 90% of accuracy for the patch-based approach and 85% for the image-based approach. Both results are based on augmented datasets and are statistically different from the ones obtained in the original datasets of the same kind. Moreover, the impact of data augmentation was evaluated in the context of image description and classification, and the results obtained using synthetic images outperformed the ones over the original datasets, as well as other recent approaches from the literature. Such results suggest promising insights related to the importance of proper data for the accurate classification concerning computer-assisted Barrett's esophagus and adenocarcinoma detection. KW - Maschinelles Lernen KW - Barrett's esophagus KW - Machine learning KW - Adenocarcinoma KW - Generative adversarial networks KW - Neuronales Netz KW - Adenocarcinom KW - Speiseröhrenkrebs KW - Diagnose Y1 - 2020 U6 - https://doi.org/10.1016/j.compbiomed.2020.104029 VL - 126 IS - November PB - Elsevier ER - TY - JOUR A1 - Froese, Vincent A1 - Jain, Brijnesh A1 - Niedermeier, Rolf A1 - Renken, Malte T1 - Comparing temporal graphs using dynamic time warping JF - Social Network Analysis and Mining N2 - Within many real-world networks, the links between pairs of nodes change over time. Thus, there has been a recent boom in studying temporal graphs. Recognizing patterns in temporal graphs requires a proximity measure to compare different temporal graphs. To this end, we propose to study dynamic time warping on temporal graphs. We define the dynamic tem- poral graph warping (dtgw) distance to determine the dissimilarity of two temporal graphs. Our novel measure is flexible and can be applied in various application domains. We show that computing the dtgw-distance is a challenging (in general) NP-hard optimization problem and identify some polynomial-time solvable special cases. Moreover, we develop a quadratic programming formulation and an efficient heuristic. In experiments on real-world data, we show that the heuristic performs very well and that our dtgw-distance performs favorably in de-anonymizing networks compared to other approaches. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-38493 VL - 10 SP - 1 EP - 16 PB - Springer Nature ER - TY - JOUR A1 - Hu, Rongbo A1 - Linner, Thomas A1 - Trummer, Julian A1 - Güttler, Jörg A1 - Kabouteh, Amir A1 - Langosch, Katharina A1 - Bock, Thomas T1 - Developing a Smart Home Solution Based on Personalized Intelligent Interior Units to Promote Activity and Customized Healthcare for Aging Society JF - Journal of Population Ageing: Special Issue on responsive engagement of older persons promoting activity and customized healthcare N2 - The world’s population is aging at an unprecedented pace. Aging society is not only a severe crisis in the developed world, but also a rigorous challenge in emerging economies. Many age-related diseases are fostered by the lack of physical, cognitive, and social activities. Increasing the activity level has many benefits for the elderly and can improve their independence. Based on the analysis of the state-of-the-art and shortcomings of the current smart home solutions, the EU-funded research project REACH aims to develop a service system that will turn clinical and care environments into personalized modular sensing, prevention, and intervention systems that encourage the elderly to become healthy through various activities. To achieve that goal, the research team developed a series of smart furniture (PI2Us) that materialize the research concepts and functionality seamlessly into the various environments. Specifically, the development process and the functionality testing results of the PI2Us are reported in detail. In addition, a simulated smart home solution concept (TRACK) integrating key assistive technologies developed is proposed to create a comprehensive interior living and care environment for elderly users. Due to its modularity and flexibility, the partial or entire solution can be easily adapted and rapidly deployed in different use case settings in Europe, which allows the project consortium to execute different testing activities. In the next phase, the research team will focus on enhancing the usability and performance of the prototypes in order to eventually push them to the market. In conclusion, this research provides an innovative smart home solution for the industry to mitigate the impact of aging society. KW - Assistive technology KW - Personalized intelligent interior units KW - Sensing technology KW - Smart furniture KW - Smart home Y1 - 2020 U6 - https://doi.org/10.1007/s12062-020-09267-6 VL - 13 IS - 1 SP - 257 EP - 280 PB - Springer Nature ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Striegl, Birgit A1 - Prem, Nina A1 - Sindersberger, Dirk T1 - Electrical Properties of Magnetoactive Boron‐Organo‐Silicon Oxide Polymers JF - Macromolecular Chemistry and Physics N2 - The electrical properties of rheopectic magnetoactive composites comprising boron-organo-silicon oxide dielectric matrices containing carbonyl iron microparticles are presented for the first time. The increase in interfacial magnetocapacitance is seen to greatly exceed that experienced when using conventional elastomeric matrices such as polydimethylsiloxane. In addition to the increase in capacitance, a simultaneous and sharp decrease in the parallel electrical resistance over several orders of magnitude is also observed. The effects are time dependent but repeatable. Potential applications include magnetically controlled frequency dependent devices, magnetic sensor systems, weighting elements for neural networks, etc. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26488 N1 - Corresponding author: Gareth J. Monkman VL - 221 IS - 4 SP - 1 EP - 8 PB - Wiley ER - TY - JOUR A1 - Metsch, P. A1 - Schmidt, H. A1 - Sindersberger, Dirk A1 - Kalina, K. A. A1 - Brummund, J. A1 - Auernhammer, Günter A1 - Monkman, Gareth J. A1 - Kästner, Markus T1 - Field-Induced Interactions in Magneto-Active Elastomers BT - A Comparison of Experiments and Simulations JF - Smart Materials and Structures N2 - In this contribution, field-induced interactions of magnetizable particles embedded into a soft elastomer matrix are analyzed with regard to the resulting mechanical deformations. By comparing experiments for two-, three- and four-particle systems with the results of finite element simulations, a fully coupled continuum model for magneto-active elastomers is validated with the help of real data for the first time. The model under consideration permits the investigation of magneto-active elastomers with arbitrary particle distances, shapes and volume fractions as well as magnetic and mechanical properties of the individual constituents. It thus represents a basis for future studies on more complex, realistic systems. Our results show a very good agreement between experiments and numerical simulations—the deformation behavior of all systems is captured by the model qualitatively as well as quantitatively. Within a sensitivity analysis, the influence of the initial particle positions on the systems' response is examined. Furthermore, a comparison of the full three-dimensional model with the often used, simplified two-dimensional approach shows the typical overestimation of resulting interactions in magneto-active elastomers. Y1 - 2020 U6 - https://doi.org/10.1088/1361-665X/ab92dc N1 - Corrigendum: Field-induced interactions in magneto-active elastomers—a comparison of experiments and simulations (2020 Smart Mater. Struct. 29 085026); https://doi.org/10.1088/1361-665X/abb98b VL - 29 IS - 8 SP - 1 EP - 10 PB - IOPscience ER - TY - JOUR A1 - Kopper, Andreas A1 - Westner, Markus A1 - Strahringer, Susanne T1 - From Shadow IT to Business-managed IT: A qualitative comparative analysis to determine configurations for successful management of IT by business entities JF - Information Systems and e-Business Management N2 - Shadow IT describes covert/hidden IT systems that are managed by business entities themselves. Additionally, there are also overt forms in practice, so-called Business-managed IT, which share most of the characteristics of Shadow IT. To better understand this phenomenon, we interviewed 29 executive IT managers about positive and negative cases of Shadow IT and Business-managed IT. By applying qualitative comparative analysis (QCA), we derived four conditions that characterize these cases: Aligned, local, simple, and volatile. The results show that there are three sufficient configurations of conditions that lead to a positive outcome; one of them even encompasses Shadow IT. The most important solution indicates that IT systems managed by business entities are viewed as being positive if they are aligned with the IT department and limited to local requirements. This allows to balance local responsiveness to changing requirements and global standardization. In contrast, IT systems that are not aligned and permanent (and either organization-wide or simple) are consistently considered as negative. Our study is the first empirical quantitative–qualitative study to shed light on the success and failure of Shadow IT and Business-managed IT. KW - Informationsmanagement KW - Wirtschaftsinformatik KW - Business-managed IT KW - Shadow IT KW - IT governance KW - Qualitative comparative analysis (QCA) Y1 - 2020 U6 - https://doi.org/10.1007/s10257-020-00472-6 VL - 18 IS - 2 SP - 209 EP - 257 ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Infrared spectral analysis of low concentration magnetoactive polymers JF - Journal of Applied Polymer Science N2 - This work concerns an area of magnetoactive polymer (MAP) research seldom considered. Traditionally only MAP with high concentrations of magnetic filler (typically between 10 and 90 wt%) have been investigated. This article deals with a hitherto neglected aspect of research, namely MAP containing lower magnetic filler concentrations (1 to 3 wt%). This article utilizes a range of spectroscopic analysis methods (Raman and FTIR) and their applicability to MAP characterization at wavelengths ranging from 2.5 to 25 mu m. Particular attention is paid to low carbonyl iron particle (CIP) concentrations in MAP for which the emergence of capillary doublets at a critical 2 wt% concentration is revealed. This results in measurable magnetic field-dependent changes in IR absorption at a wavelength of 4.255 mu m together with a detectable CO2 susceptibility. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48366. KW - ELASTOMERS KW - magnetism and magnetic properties KW - sensors and actuators KW - spectroscopy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-25913 SN - 1097-4628 N1 - Corresponding author: Nina Prem VL - 137 IS - 7 SP - 1 EP - 7 PB - Wiley ER - TY - JOUR A1 - von Bary, Benedikt A1 - Westner, Markus A1 - Strahringer, Susanne T1 - IT-Backsourcing BT - Empirische Erkenntnisse und Handlungsempfehlungen für eine erfolgreiche Re-Integration der IT-Serviceerbringung JF - HMD Praxis der Wirtschaftsinformatik N2 - IT-Backsourcing bezeichnet die Re-Integration vormals outgesourcter IT-Services zurück zum auslagernden Unternehmen. Die vorliegende Studie stellt die Ergebnisse einer Umfrage unter IT-Managern zu Einflussfaktoren von IT-Backsourcing-Entscheidungen vor. Es lässt sich feststellen, dass IT-Backsourcing von Unternehmen in unterschiedlichen Branchen und für eine Vielzahl an unterschiedlichen IT-Services, wie z. B. Applikationsentwicklung oder Infrastruktur-Leistungen, durchgeführt wird. Hauptgründe für die Entscheidung für ein IT-Backsourcing sind mangelnde Qualität, hohe Kosten sowie eine schlechte Beziehung zum IT-Dienstleister. Die Ergebnisse der Umfrage zeigen, dass diejenigen Unternehmen, die sich für ein Backsourcing entschieden haben, nach der Entscheidung insgesamt zufriedener waren als diejenigen, die in einer Outsourcing-Beziehung geblieben sind. Zudem werden verschiedene Handlungsempfehlungen für IT-Manager aufgezeigt. Zur Ausarbeitung einer zukunftsorientieren IT-Sourcing-Strategie empfiehlt es sich, eine service-spezifische Sourcing-Strategie zu verfolgen und entsprechend spezialisierte Dienstleister einzusetzen. Im Falle einer Entscheidung für ein IT-Backsourcing sollten verschiedene Erfolgsfaktoren beachtetet werden, wie z. B. eine frühzeitige Neubesetzung von Schlüsselstellen sowie ein lückenloser Wissenstransfer. KW - Betriebliches Informationssystem KW - Insourcing KW - Backsourcing KW - Insourcing KW - IT-Sourcing KW - Re-Integration KW - IT-Service Y1 - 2020 U6 - https://doi.org/10.1365/s40702-020-00591-1 VL - 57 IS - 4 SP - 849 EP - 865 PB - Springer ER -