450 research outputs found
Acoustic Stimuli Can Improve and Impair Somatosensory Perception
The integration of stimuli from different sensory modalities forms the basis for human perception. While the relevant impact of visual stimuli on the perception of other sensory modalities is recognized, much less is known about the impact of auditory stimuli on general sensory processing. This study aims to investigate the effect of acoustic stimuli on the processing of somatosensory stimuli using real noise (i.e., unpleasant everyday noise, RN) and neutral white noise ( WN ). To this purpose, we studied 20 healthy human subjects between 20 and 29 years of age (mean: 24, SD: ±1.9 years sex ratio 1:1). Somatosensory perception was evaluated using mechanical detection threshold (MDT) of the skin on the back of the dominant hand. To investigate the underlying mechanisms in the brain, fMRI was performed while applying acoustic stimulation (RN and WN) and tactile stimulation of the dominant hand. Here we show that acoustic stimulation with noise alters the perception of touch on the skin. We found that the effect of RN and WN differed. RN leads to an improved tactile perception, whereas WN impaired tactile perception. These changes go along with significant differences in brain activity and connectivity. WN is associated with a significant increase in brain activity in multiple brain areas such as the auditory and somatosensory cortex, parietal association cortex, and the thalamus compared to RN . With tactile stimulation of the skin, the flow of information in these brain areas is altered. While with RN the information flow from the thalamus to the somatosensory cortex is prominent, the network activity pattern changes under WN revealing an increase in interaction between multiple networks. Unpleasant noise inhibits the multisensory integration and enables a more efficient unimodal perception in the somatosensory system, improving perception. Whether this is to be interpreted as a temporary increase in phasic alertness or by a stronger filter function of the thalamus with a preference for unimodal stimuli is still open for debate
ResBuilder: Automated Learning of Depth with Residual Structures
In this work, we develop a neural architecture search algorithm, termed
Resbuilder, that develops ResNet architectures from scratch that achieve high
accuracy at moderate computational cost. It can also be used to modify existing
architectures and has the capability to remove and insert ResNet blocks, in
this way searching for suitable architectures in the space of ResNet
architectures. In our experiments on different image classification datasets,
Resbuilder achieves close to state-of-the-art performance while saving
computational cost compared to off-the-shelf ResNets. Noteworthy, we once tune
the parameters on CIFAR10 which yields a suitable default choice for all other
datasets. We demonstrate that this property generalizes even to industrial
applications by applying our method with default parameters on a proprietary
fraud detection dataset
Recent development in adsorption materials and heat exchangers for thermally driven heat pumps
Part of:
Thermally driven heat pumps for heating and cooling. –
Ed.: Annett Kühn –
Berlin: Universitätsverlag der TU Berlin, 2013
ISBN 978-3-7983-2686-6 (print)
ISBN 978-3-7983-2596-8 (online)
urn:nbn:de:kobv:83-opus4-39458
[http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458]Adsorption chillers and heat pumps are a promising technology for the supply of heating and cooling, especially in the small scale range. Therefore, adsorption materials with a high load capacity and heat exchangers with effective heat and mass transfer ratios are required. To compare the characteristics of adsorption-refrigerant working pairs from different manufacturers a common measurement method is required. This paper gives a literature survey about the state of the art in adsorption material developments and proposes a common measurement procedure for adsorbents. Moreover the latest activities in heat exchanger developments for adsorption heat exchangers and evaporators are represented
Debugging Quadrocopter Trajectories in Mixed Reality
Debugging and monitoring robotic applications is a very intricate and error-prone task. To this end, we propose a mixed-reality approach to facilitate this process along a concrete scenario. We connected the Microsoft HoloLens smart glass to the Robot Operating System (ROS), which is used to control robots, and visualize arbitrary flight data of a quadrocopter. Hereby, we display holograms correctly in the real world based on a conversion of the internal tracking coordinates into coordinates provided by a motion capturing system. Moreover, we describe the synchronization process of the internal tracking with the motion capturing. Altogether, the combination of the HoloLens and the external tracking system shows promising preliminary results. Moreover, our approach can be extended to directly manipulate source code through its mixed-reality visualization and offers new interaction methods to debug and develop robotic applications
Corticomuscular synchronization with small and large dynamic force output
BACKGROUND: Over the last years much research has been devoted to investigating the synchronization between cortical motor and muscular activity as measured by EEG/MEG-EMG coherence. The main focus so far has been on corticomuscular coherence (CMC) during static force condition, for which coherence in beta-range has been described. In contrast, we showed in a recent study [1] that dynamic force condition is accompanied by gamma-range CMC. The modulation of the CMC by various dynamic force amplitudes, however, remained uninvestigated. The present study addresses this question. We examined eight healthy human subjects. EEG and surface EMG were recorded simultaneously. The visuomotor task consisted in isometric compensation for 3 forces (static, small and large dynamic) generated by a manipulandum. The CMC, the cortical EEG spectral power (SP), the EMG SP and the errors in motor performance (as the difference between target and exerted force) were analyzed. RESULTS: For the static force condition we found the well-documented, significant beta-range CMC (15-30Hz) over the contralateral sensorimotor cortex. Gamma-band CMC (30-45Hz) occurred in both small and large dynamic force conditions without any significant difference between both conditions. Although in some subjects beta-range CMC was observed during both dynamic force conditions no significant difference between conditions could be detected. With respect to the motor performance, the lowest errors were obtained in the static force condition and the highest ones in the dynamic condition with large amplitude. However, when we normalized the magnitude of the errors to the amplitude of the applied force (relative errors) no significant difference between both dynamic conditions was observed. CONCLUSIONS: These findings confirm that during dynamic force output the corticomuscular network oscillates at gamma frequencies. Moreover, we show that amplitude modulation of dynamic force has no effect on the gamma CMC in the low force range investigated. We suggest that gamma CMC is rather associated with the internal state of the sensorimotor system as supported by the unchanged relative error between both dynamic conditions
Praktiken der Grenzbearbeitung in den Lebensgeschichten der "DDR-Kinder aus Namibia"
"Im Rahmen eines Solidaritätsprojektes zwischen der South West African People's Organization (SWAPO) und der DDR wurden von 1979 bis 1989 ca. 430 namibische Kinder in die DDR gebracht, um zur Elite eines zukünftig befreiten Namibias ausgebildet zu werden. In diesem Beitrag fragen wir unter Rückgriff auf empirisches Material nach Praktiken der Grenzbearbeitung im Rahmen des länderübergreifenden Betreuungskontextes und nach der Rückführung der Kinder und Jugendlichen im Jahr 1990. Entlang der biografischen Stationen Flüchtlingslager, Kinderheim, Internatsschule und Rückführung rekonstruieren wir, wie und durch wen Grenzen - vor allem zwischen SWAPO bzw. Namibia und DDR - (re)produziert, aber auch verflochten und irritiert wurden." (Autorenreferat)"As part of a solidarity project between the South West African People's Organization (SWAPO) and the GDR, approximately 430 Namibian children were brought to the GDR from 1979 to 1989 in order to be trained to be part of the elite of a prospective liberated Namibia. In this paper, we used empirical data to investigate the processes of dealing with boundaries within the children's border-crossing care situation and also after their repatriation to Namibia in 1990. Along the biographical points of the refugee camp, the children's home, the boarding school and the repatriation, we reconstruct how and by whom borders - especially between the SWAPO respectively Namibia, and the GDR - have been (re)produced, but also integrated and irritated." (author's abstract
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