322 research outputs found
Влияние импульсных магнитных полей на электрические и прочностные характеристики полимерной изоляции кабелей
An efficient architecture for the integration of sensor and actuator networks into the future internet
In the future, sensors will enable a large variety of new services in
different domains. Important application areas are service adaptations in
fixed and mobile environments, ambient assisted living, home automation,
traffic management, as well as management of smart grids. All these
applications will share a common property, the usage of networked sensors and
actuators. To ensure an efficient deployment of such sensor-actuator
networks, concepts and frameworks for managing and distributing sensor data
as well as for triggering actuators need to be developed. In this paper, we
present an architecture for integrating sensors and actuators into the future
Internet. In our concept, all sensors and actuators are connected via
gateways to the Internet, that will be used as comprehensive transport
medium. Additionally, an entity is needed for registering all sensors and
actuators, and managing sensor data requests. We decided to use a
hierarchical structure, comparable to the Domain Name Service. This approach
realizes a cost-efficient architecture disposing of "plug and play"
capabilities and accounting for privacy issues
Context-based user grouping for multi-casting in heterogeneous radio networks
Along with the rise of sophisticated smartphones and smart spaces, the
availability of both static and dynamic context information has steadily been
increasing in recent years. Due to the popularity of social networks, these
data are complemented by profile information about individual users. Making
use of this information by classifying users in wireless networks enables
targeted content and advertisement delivery as well as optimizing network
resources, in particular bandwidth utilization, by facilitating group-based
multi-casting. In this paper, we present the design and implementation of a
web service for advanced user classification based on user, network, and
environmental context information. The service employs simple and advanced
clustering algorithms for forming classes of users. Available service
functionalities include group formation, context-aware adaptation, and
deletion as well as the exposure of group characteristics. Moreover, the
results of a performance evaluation, where the service has been integrated in
a simulator modeling user behavior in heterogeneous wireless systems, are
presented
Сложность алгоритмов криптографической системы Эль–Гамаля и ихэффективность
Objective. - Electrical remodeling as well as atrial contractile dysfunction after the conversion of atrial fibrillation (AF) to sinus rhythm (SR) are mainly caused by a reduction of the inward L-type Ca2+ current (ICaL). We investigated whether the expression of L-type Ca2+-channel subunits was reduced in atrial myocardium of AF patients. Methods. - Right atrial appendages were obtained from patients undergoing coronary artery bypass graft surgery (CAD, n = 35) or mitral valve surgery (MVD, n = 37). Seventeen of the CAD patients and 18 of the MVD patients were in chronic (>3 months) AF, whereas the others were in SR. The protein expression of the L-type Ca2+-channel subunits {alpha}1C and {beta}2 was quantified by western blot analysis. Furthermore, we measured the density of dihydropyridine (DHP)-binding sites of the L-type Ca2+ channel using 3H-PN220-100 as radioligand. Results. - Surprisingly, the {alpha}1C and the {beta}2-subunit expression was not altered in atrial myocardium of AF patients. Also, the DHP-binding site density was unchanged. Conclusion. - The protein expression of the L-type Ca2+-channel subunits {alpha}1C or {beta}2 is not reduced in atrial myocardium of AF patients. Therefore, the reduced ICaL might be due to downregulation of other accessory subunits ({alpha}2{delta}), expression of aberrant subunits, changes in channel trafficking or alterations in channel function
Current controversies in determining the main mechanisms of atrial fibrillation
Despite considerable basic research into the mechanisms of atrial fibrillation (AF), not much progress has been made in the prognosis of patients with AF. With the exception of anticoagulant therapy, current treatments for AF still do not improve major cardiovascular outcomes. This may be due partly to the diverse aetiology of AF with increasingly more factors found to contribute to the arrhythmia. In addition, a strong increase has been seen in the technological complexity of the methods used to quantify the main pathophysiological alterations underlying the initiation and progression of AF. Because of the lack of standardization of the technological approaches currently used, the perception of basic mechanisms of AF varies widely in the scientific community. Areas of debate include the role of Ca2+-handling alterations associated with AF, the contribution and noninvasive assessment of the degree of atrial fibrosis, and the best techniques to identify electrophysiological drivers of AF. In this review, we will summarize the state of the art of these controversial topics and describe the diverse approaches to investigating and the scientific opinions on leading AF mechanisms. Finally, we will highlight the need for transparency in scientific reporting and standardization of terminology, assumptions, algorithms and experimental conditions used for the development of better AF therapies. Content List - Read more articles from the symposium: Atrial fibrillation - from atrial extrasystoles to atrial cardiomyopathy. What have we learned from basic science and interventional procedures
Reference Network and Localization Architecture for Smart Manufacturing based on 5G
5G promises to shift Industry 4.0 to the next level by allowing flexible
production. However, many communication standards are used throughout a
production site, which will stay so in the foreseeable future. Furthermore,
localization of assets will be equally valuable in order to get to a higher
level of automation. This paper proposes a reference architecture for a
convergent localization and communication network for smart manufacturing that
combines 5G with other existing technologies and focuses on high-mix low-volume
application, in particular at small and medium-sized enterprises. The
architecture is derived from a set of functional requirements, and we describe
different views on this architecture to show how the requirements can be
fulfilled. It connects private and public mobile networks with local networking
technologies to achieve a flexible setup addressing many industrial use cases.Comment: 10 pages; submitted to 6th International Conference on
System-Integrated Intelligence. Intelligent, flexible and connected systems
in products and production, 7-9 September Genova, Ital
Machine Learning for QoS Prediction in Vehicular Communication: Challenges and Solution Approaches
As cellular networks evolve towards the 6th generation, machine learning is
seen as a key enabling technology to improve the capabilities of the network.
Machine learning provides a methodology for predictive systems, which can make
networks become proactive. This proactive behavior of the network can be
leveraged to sustain, for example, a specific quality of service requirement.
With predictive quality of service, a wide variety of new use cases, both
safety- and entertainment-related, are emerging, especially in the automotive
sector. Therefore, in this work, we consider maximum throughput prediction
enhancing, for example, streaming or high-definition mapping applications. We
discuss the entire machine learning workflow highlighting less regarded aspects
such as the detailed sampling procedures, the in-depth analysis of the dataset
characteristics, the effects of splits in the provided results, and the data
availability. Reliable machine learning models need to face a lot of challenges
during their lifecycle. We highlight how confidence can be built on machine
learning technologies by better understanding the underlying characteristics of
the collected data. We discuss feature engineering and the effects of different
splits for the training processes, showcasing that random splits might
overestimate performance by more than twofold. Moreover, we investigate diverse
sets of input features, where network information proved to be most effective,
cutting the error by half. Part of our contribution is the validation of
multiple machine learning models within diverse scenarios. We also use
explainable AI to show that machine learning can learn underlying principles of
wireless networks without being explicitly programmed. Our data is collected
from a deployed network that was under full control of the measurement team and
covered different vehicular scenarios and radio environments.Comment: 18 pages, 12 Figures. Accepted on IEEE Acces
Berlin V2X: A Machine Learning Dataset from Multiple Vehicles and Radio Access Technologies
The evolution of wireless communications into 6G and beyond is expected to
rely on new machine learning (ML)-based capabilities. These can enable
proactive decisions and actions from wireless-network components to sustain
quality-of-service (QoS) and user experience. Moreover, new use cases in the
area of vehicular and industrial communications will emerge. Specifically in
the area of vehicle communication, vehicle-to-everything (V2X) schemes will
benefit strongly from such advances. With this in mind, we have conducted a
detailed measurement campaign that paves the way to a plethora of diverse
ML-based studies. The resulting datasets offer GPS-located wireless
measurements across diverse urban environments for both cellular (with two
different operators) and sidelink radio access technologies, thus enabling a
variety of different studies towards V2X. The datasets are labeled and sampled
with a high time resolution. Furthermore, we make the data publicly available
with all the necessary information to support the onboarding of new
researchers. We provide an initial analysis of the data showing some of the
challenges that ML needs to overcome and the features that ML can leverage, as
well as some hints at potential research studies.Comment: 5 pages, 6 figures. Accepted for presentation at IEEE conference
VTC2023-Spring. Available dataset at
https://ieee-dataport.org/open-access/berlin-v2
The prognosis of allocentric and egocentric neglect : evidence from clinical scans
We contrasted the neuroanatomical substrates of sub-acute and chronic visuospatial deficits associated with different aspects of unilateral neglect using computed tomography scans acquired as part of routine clinical diagnosis. Voxel-wise statistical analyses were conducted on a group of 160 stroke patients scanned at a sub-acute stage. Lesion-deficit relationships were assessed across the whole brain, separately for grey and white matter. We assessed lesions that were associated with behavioural performance (i) at a sub-acute stage (within 3 months of the stroke) and (ii) at a chronic stage (after 9 months post stroke). Allocentric and egocentric neglect symptoms at the sub-acute stage were associated with lesions to dissociated regions within the frontal lobe, amongst other regions. However the frontal lesions were not associated with neglect at the chronic stage. On the other hand, lesions in the angular gyrus were associated with persistent allocentric neglect. In contrast, lesions within the superior temporal gyrus extending into the supramarginal gyrus, as well as lesions within the basal ganglia and insula, were associated with persistent egocentric neglect. Damage within the temporo-parietal junction was associated with both types of neglect at the sub-acute stage and 9 months later. Furthermore, white matter disconnections resulting from damage along the superior longitudinal fasciculus were associated with both types of neglect and critically related to both sub-acute and chronic deficits. Finally, there was a significant difference in the lesion volume between patients who recovered from neglect and patients with chronic deficits. The findings presented provide evidence that (i) the lesion location and lesion size can be used to successfully predict the outcome of neglect based on clinical CT scans, (ii) lesion location alone can serve as a critical predictor for persistent neglect symptoms, (iii) wide spread lesions are associated with neglect symptoms at the sub-acute stage but only some of these are critical for predicting whether neglect will become a chronic disorder and (iv) the severity of behavioural symptoms can be a useful predictor of recovery in the absence of neuroimaging findings on clinical scans. We discuss the implications for understanding the symptoms of the neglect syndrome, the recovery of function and the use of clinical scans to predict outcome
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