Search results for "NETWORKS"
showing 10 items of 3260 documents
Energy Efficient Consecutive Packet Transmissions in Receiver-Initiated Wake-Up Radio Enabled WSNs
2018
In wake-up radio (WuR)-enabled wireless sensor networks, data communication among nodes is triggered in an on-demand manner, by either a sender or a receiver. For receiver-initiated WuR (RI-WuR), a receiving node wakes up sending nodes through a wake-up call. Correspondingly sending nodes transmit packets in a traditional way by competing with one another multiple times in a single operational cycle. In this paper, we propose a receiver-initiated consecutive packet transmission WuR (RI-CPT-WuR) medium access control (MAC) protocol, which eliminates multiple competitions to achieve higher energy efficiency. Furthermore, we develop two associated discrete time Markov chains (DTMCs) for evalua…
Enforcing mobile security with location-aware role-based access control
2013
This paper describes how location-aware role-based access control RBAC can be implemented on top of the Geospatial eXtensible Access Control Markup Language GeoXACML. It furthermore sketches how spatial separation of duty constraints both static and dynamic can be implemented using GeoXACML on top of the XACML RBAC profile. The solution uses physical addressing of geographical locations, which facilitates easy deployment of authorisation profiles to the mobile device. Location-aware RBAC can be used to implement location-dependent access control and also other security enhancing solutions on mobile devices, such as location-dependent device locking, firewall, intrusion prevention or payment…
V1 non-linear properties emerge from local-to-global non-linear ICA
2006
It has been argued that the aim of non-linearities in different visual and auditory mechanisms may be to remove the relations between the coefficients of the signal after global linear ICA-like stages. Specifically, in Schwartz and Simoncelli (2001), it was shown that masking effects are reproduced by fitting the parameters of a particular non-linearity in order to remove the dependencies between the energy of wavelet coefficients. In this work, we present a different result that supports the same efficient encoding hypothesis. However, this result is more general because, instead of assuming any specific functional form for the non-linearity, we show that by using an unconstrained approach…
High-Precision Multiphoton Ionization of Accelerated Laser-Ablated Species
2018
We demonstrate that the pulsed-time structure and high-peak ion intensity provided by the laser-ablation process can be directly combined with the high resolution, high efficiency, and low background offered by collinear resonance ionization spectroscopy. This simple, versatile, and powerful method offers new and unique opportunities for high-precision studies of atomic and molecular structures, impacting fundamental and applied physics research. We show that even for ion beams possessing a relatively large energy spread, high-resolution hyperfine-structure measurements can be achieved by correcting the observed line shapes with the time-of-flight information of the resonantly ionized ions.…
Dynamics of Singlet Oxygen Molecule Trapped in Silica Glass Studied by Luminescence Polarization Anisotropy and Density Functional Theory
2020
The support from M-ERANET project “MyND” is acknowledged. A.A., M.M-S., and L.R. were supported by the Research Council of Lithuania (Grant M-ERA.NET-1/2015). The authors thank A. Pasquarello for providing the structures of the amorphous SiO 2 matrix for our computational work and K. Kajihara (Tokyo Metropolitan University) for valuable advice in PL kinetics measurements.
Thermo- and photo-modulation of exciplex fluorescence in a 3D spin crossover Hofmann-type coordination polymer
2018
[EN] The search for bifunctional materials showing synergies between spin crossover (SCO) and luminescence has attracted substantial interest since they could be promising platforms for new switching electronic and optical technologies. In this context, we present the first three-dimensional Fe-II Hofmann-type coordination polymer exhibiting SCO properties and luminescence. The complex {Fe-II(bpben)[Au(CN)(2)]}@pyr (bpben = 1,4-bis(4-pyridyl)benzene) functionalized with pyrene (pyr) guests undergoes a cooperative multi-step SCO, which has been investigated by single crystal X-ray diffraction, single crystal UV-Vis absorption spectroscopy, and magnetic and calorimetric measurements. The resu…
Using a neural network for predicting the average grain size in friction stir welding processes
2009
In the paper the microstructural phenomena in terms of average grain size occurring in friction stir welding (FSW) processes are focused. A neural network was linked to a finite element model (FEM) of the process to predict the average grain size values. The utilized net was trained starting from experimental data and numerical results of butt joints and then tested on further butt, lap and T-joints. The obtained results show the capability of the AI technique in conjunction with the FE tool to predict the final microstructure in the FSW joints.
Mechanical and microstructural properties prediction by artificial neural networks in FSW processes of dual phase titanium alloys
2012
Abstract Friction Stir Welding (FSW), as a solid state welding process, seems to be one of the most promising techniques for joining titanium alloys avoiding a large number of difficulties arising from the use of traditional fusion welding processes. In order to pursue cost savings and a time efficient design, the development of numerical simulations of the process can represent a valid choice for engineers. In the paper an artificial neural network was properly trained and linked to an existing 3D FEM model for the FSW of Ti–6Al–4V titanium alloy, with the aim to predict both the microhardness values and the microstructure of the welded butt joints at the varying of the main process parame…
Progress in Violet Light-Emitting Diodes Based on ZnO/GaN Heterojunction
2020
Progress in light-emitting diodes (LEDs) based on ZnO/GaN heterojunctions has run into several obstacles during the last twenty years. While both the energy bandgap and lattice parameter of the two semiconductors are favorable to the development of such devices, other features related to the electrical and structural properties of the GaN layer prevent an efficient radiative recombination. This work illustrates some advances made on ZnO/GaN-based LEDs, by using high-thickness GaN layers for the p-region of the device and an ad hoc device topology. Heterojunction LEDs consist of a quasicoalesced non-intentionally doped ZnO nanorod layer deposited by chemical bath deposition onto a metal&ndash
RFID epidermal sensor including hydrogel membranes for wound monitoring and healing
2015
This contribution experimentally demonstrates for the first time the feasibility of joint application of passive UHF RFID technology and hydrogel membranes to fabricate smart plasters able to gather and remotely transmit information on the conditions of human skin. In particular, this intelligent plaster is sensitive to temperature and fluid uptake/release and could open interesting scenarios in wound healing monitoring and drug delivery.