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21.
Nadia Gremer Dipl.-Ing. Univ.Prof. Dipl.-Ing. Dr. techn. Christoph Adam Dipl.-Ing. Dr. techn. Lukas Moschen Ricardo A. Medina 《Stahlbau》2020,89(1):4-15
Influence of damping modelling on the acceleration response of an earthquake-excited steel frame structure As part of a case study, this paper deals with the effect of different damping approaches on the computed acceleration response of a planar, regular, elastic steel frame under earthquake excitation. In this study, not only the amplification of the horizontal ground acceleration, as is usual in earthquake engineering, but also the amplification of the vertical ground acceleration is considered. It is shown that Rayleigh damping used in accordance with engineering and scientific practice, leads to a minor amplification of the vertical ground acceleration only because damping of the vertical modes is too large compared to the lateral modes. This explains the erroneous assumption that the amplification of the vertical ground acceleration is negligible. In contrast, Rayleigh damping based on effective vertical mass participation overestimates both horizontal and vertical structural acceleration. The implementation of the inherent damping in the computational model in the form of modal damping, however, leads to a realistic computational prediction of the acceleration response in both directions. 相似文献
22.
Lukas Baumgärtel Robin Schönbach Robert Hartung Alexander Ruwoldt Prof. Dr.-Ing. Katharina Klemt-Albert 《Bautechnik》2020,97(12):817-825
BIM-based collaboration – a phase-oriented process concept for virtual design reviews Object-based, digital 3-D building models are used as a central source of information for all project participants when Building Information Modeling is applied and are thus increasingly becoming the focus of meetings in construction projects. However, there are hardly any orientations or standards for the implementation of virtual design reviews, which concern clear process structures, role distributions as well as basic IT requirements for the rooms of digital meetings. The potentials of model-based collaboration through the introduction of BIM therefore often remain unused. The present article takes up the process conditions of the BIM methodology and influencing variables of meeting processes, describes the implementation of virtual design reviews in three real projects and, as a result of the analysis of these three scenarios, shows a phase-oriented innovative process concept for the integral preparation, realisation and post-processing of a virtual design review, including a clear distribution of roles as well as recommendations on requirements for data management, room equipment and IT. 相似文献
23.
Memristors are deemed to be the electrical twin to biological synapses. They enable emulation of human memory functionalities such as learning, memorizing, and forgetting. The present hydrothermally grown titanium dioxide nanowire array memristive devices have shown to be able to mimic synaptic behaviors. As well as spike-rate dependent plasticity, excitatory postsynaptic currents, and paired pulse facilitation, high endurance, and on/off ratios for the nanowire arrays are presented. Decay fitting of postsynaptic currents with Kohlrausch's equation shows lifetimes of few milliseconds up to several hundred seconds, offering the possibility of a short-term to long-term memory transition. Furthermore, a strong dependence of the lifetime of the signals on the frequency and amplitude of the stimulation pulses is observed. 相似文献
24.
Thomas Küstner Annika Liebgott Lukas Mauch Petros Martirosian Fabian Bamberg Konstantin Nikolaou Bin Yang Fritz Schick Sergios Gatidis 《Magma (New York, N.Y.)》2018,31(2):243-256
Objectives
Our objectives were to provide an automated method for spatially resolved detection and quantification of motion artifacts in MR images of the head and abdomen as well as a quality control of the trained architecture.Materials and methods
T1-weighted MR images of the head and the upper abdomen were acquired in 16 healthy volunteers under rest and under motion. Images were divided into overlapping patches of different sizes achieving spatial separation. Using these patches as input data, a convolutional neural network (CNN) was trained to derive probability maps for the presence of motion artifacts. A deep visualization offers a human-interpretable quality control of the trained CNN. Results were visually assessed on probability maps and as classification accuracy on a per-patch, per-slice and per-volunteer basis.Results
On visual assessment, a clear difference of probability maps was observed between data sets with and without motion. The overall accuracy of motion detection on a per-patch/per-volunteer basis reached 97%/100% in the head and 75%/100% in the abdomen, respectively.Conclusion
Automated detection of motion artifacts in MRI is feasible with good accuracy in the head and abdomen. The proposed method provides quantification and localization of artifacts as well as a visualization of the learned content. It may be extended to other anatomic areas and used for quality assurance of MR images.25.
26.
Aibek Sarimbekov Lukas Stadler Lubomír Bulej Andreas Sewe Andrej Podzimek Yudi Zheng Walter Binder 《Software》2016,46(8):1053-1089
Originally developed with a single language in mind, the JVM is now targeted by numerous programming languages—its automatic memory management, just‐in‐time compilation, and adaptive optimizations—making it an attractive execution platform. However, the garbage collector, the just‐in‐time compiler, and other optimizations and heuristics were designed primarily with the performance of Java programs in mind. Consequently, many of the languages targeting the JVM, and especially the dynamically typed languages, are suffering from performance problems that cannot be simply solved at the JVM side. In this article, we aim to contribute to the understanding of the character of the workloads imposed on the JVM by both dynamically typed and statically typed JVM languages. To this end, we introduce a new set of dynamic metrics for workload characterization, along with an easy‐to‐use toolchain to collect the metrics. We apply the toolchain to applications written in six JVM languages (Java, Scala, Clojure, Jython, JRuby, and JavaScript) and discuss the findings. Given the recently identified importance of inlining for the performance of Scala programs, we also analyze the inlining behavior of the HotSpot JVM when executing bytecode originating from different JVM languages. As a result, we identify several traits in the non‐Java workloads that represent potential opportunities for optimization. © 2015 The Authors. Software: Practice and Experience Published by John Wiley & Sons Ltd. 相似文献
27.
Lukas Oesinghaus Johannes Schlipf Nadja Giesbrecht Lin Song Yinghong Hu Thomas Bein Pablo Docampo Peter Müller‐Buschbaum 《Advanced Materials Interfaces》2016,3(19)
Efficient perovskite solar cells can be produced by a wide variety of different methods. Previous results show that controlling the film morphology is critical to enhance the efficiency of the prepared devices. Here, grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) is used to study the morphology and especially the orientation distribution of CH3NH3PbI3 (MAPI) perovskite films prepared by five typical methods. We find that the investigated one‐step methods produce non‐oriented films, while the two‐step deposition methods produce varying degrees of orientation depending on the method chosen to convert the highly oriented PbI2 precursor, providing direct evidence for different perovskite conversion mechanisms. In particular, we show that the morphology and crystal orientation of MAPI films is tunable by varying the spin‐coating temperature and by adding chloride to the conversion solution. By relating the precursor morphology to the resulting MAPI film morphology, we link the observed preferential orientations to specific conversion mechanisms, thereby establishing GIWAXS as an important tool toward a rational development of new synthesis methods. 相似文献
28.
Ivanina Mutisheva Steve Robatel Lukas Briswyl Mirjam Schenk 《International journal of molecular sciences》2022,23(18)
Although single-cell RNA sequencing (scRNA-seq) is currently the gold standard for the analysis of cell-specific expression profiles, the options for processing, staining, and preserving fresh cells remain very limited. Immediate and correct tissue processing is a critical determinant of scRNA-seq success. One major limitation is the restricted compatibility of fixation approaches, which must not destabilize or alter antibody labeling or RNA content or interfere with cell integrity. An additional limitation is the availability of expensive, high-demand cell-sorting equipment to exclude debris and dead or unwanted cells before proceeding with sample sequencing. The goal of this study was to develop a method that allows cells to be fixed and stored prior to FACS sorting for scRNA-seq without compromising the quality of the results. Finally, the challenge of preserving as many living cells as possible during tissue processing is another crucial issue addressed in this study. Our study focused on pancreatic ductal adenocarcinoma samples, where the number of live cells is rather limited, as in many other tumor tissues. Harsh tissue dissociation methods and sample preparation for analysis can negatively affect cell viability. Using the murine pancreatic cancer model Pan02, we evaluated the semi-automated mechanical/enzymatic digestion of solid tumors by gentleMACS Dissociator and compared it with mechanical dissociation of the same tissue. Moreover, we investigated a type of cell fixation that is successful in preserving cell RNA integrity yet compatible with FACS and subsequent scRNA-sequencing. Our protocol allows tissue to be dissociated and stained in one day and proceeds to cell sorting and scRNA-seq later, which is a great advantage for processing clinical patient material. 相似文献
29.
Lukas Babylon Fabian Schmitt Yannik Franke Tim Hubert Gunter P. Eckert 《International journal of molecular sciences》2022,23(15)
Increased amyloid beta (Aβ) levels and mitochondrial dysfunction (MD) in the human brain characterize Alzheimer disease (AD). Folic acid, magnesium and vitamin B6 are essential micro-nutrients that may provide neuroprotection. Bioenergetic parameters and amyloid precursor protein (APP) processing products were investigated in vitro in human neuroblastoma SH-SY5Y-APP695 cells, expressing neuronal APP, and in vivo, in the invertebrate Caenorhabditis elegans (CL2006 & GMC101) expressing muscular APP. Model organisms were incubated with either folic acid and magnesium-orotate (ID63) or folic acid, magnesium-orotate and vitamin B6 (ID64) in different concentrations. ID63 and ID64 reduced Aβ, soluble alpha APP (sAPPα), and lactate levels in SH-SY5Y-APP695 cells. The latter might be explained by enhanced expression of lactate dehydrogenase (LDHA). Micronutrient combinations had no effects on mitochondrial parameters in SH-SY5Y-APP695 cells. ID64 showed a significant life-prolonging effect in C. elegans CL2006. Incubation of GMC101 with ID63 significantly lowered Aβ aggregation. Both combinations significantly reduced paralysis and thus improved the phenotype in GMC101. Thus, the combinations of the tested biofactors are effective in pre-clinical models of AD by interfering with Aβ related pathways and glycolysis. 相似文献
30.
Bilal Alashkar Alhamwe Daniel P. Potaczek Sarah Miethe Fahd Alhamdan Lukas Hintz Arslan Magomedov Holger Garn 《International journal of molecular sciences》2021,22(9)
Extracellular vesicles (EVs) are membranous structures, which are secreted by almost every cell type analyzed so far. In addition to their importance for cell-cell communication under physiological conditions, EVs are also released during pathogenesis and mechanistically contribute to this process. Here we summarize their functional relevance in asthma, one of the most common chronic non-communicable diseases. Asthma is a complex persistent inflammatory disorder of the airways characterized by reversible airflow obstruction and, from a long-term perspective, airway remodeling. Overall, mechanistic studies summarized here indicate the importance of different subtypes of EVs and their variable cargoes in the functioning of the pathways underlying asthma, and show some interesting potential for the development of future therapeutic interventions. Association studies in turn demonstrate a good diagnostic potential of EVs in asthma. 相似文献