Downlink cross‐layer scheduling strategies for long‐term evolution and long‐term evolution‐advanced systems

The most recent trend in the Information and Communication Technology world is toward an ever growing demand of mobile heterogeneous services that imply the management of different quality of service requirements and priorities among different type of users. The long‐term evolution (LTE)/LTE‐advanced standards have been introduced aiming to cope with this challenge. In particular, the resource allocation problem in downlink needs to be carefully considered. Herein, a solution is proposed by resorting to a modified multidimensional multiple‐choice knapsack problem modeling, leading to an efficient solution. The proposed algorithm is able to manage different traffic flows taking into account users priority, queues delay, and channel conditions achieving quasi‐optimal performance results with a lower complexity. The numerical results show the effectiveness of the proposed solution with respect to other alternatives. Copyright © 2013 John Wiley & Sons, Ltd.     

MgO nanoparticles synthesized starting from an innovative one‐step process

Nanosized MgO is a functional material showing a great promise as destructive adsorbent for toxic chemical agents, unique optical electronic, magnetic, thermal, and mechanical properties, as well as in good bactericidal performance in aqueous environments and in the cancer therapy. In this study, MgO nanoparticles are obtained by thermal decomposition of nanosized Mg(OH)₂, which are synthesized by means of an innovative, time and cost‐effective, scalable, and patented method. The nanoparticles are characterized by means of several techniques such as thermal analyses, X‐ray diffraction analysis, infrared spectroscopy, transmission electron microscopy, atomic force microscopy, and surface area measurements (BET). After a pseudomorphic decomposition of the hydroxide precursor, pure and crystalline MgO nanoparticles are obtained. These nanoparticles are roughly spherical, monodispersed, and monocrystalline, having size ≤10 nm. Moreover, they exhibited a surface area up to 178 m²/g, revealing a bimodal mesoporous distribution with the important part of the pores with dimensions peaked at 4.87 nm.     

Limited Memory Block Preconditioners for Fast Solution of Fractional Partial Differential Equations

An innovative block structured with sparse blocks multi iterative preconditioner for linear multistep formulas used in boundary value form is proposed here to accelerate GMRES, FGMRES and BiCGstab(l). The preconditioner is based on block \(\omega \)-circulant matrices and a short-memory approximation of the underlying Jacobian matrix of the fractional partial differential equations. Convergence results, numerical tests and comparisons with other techniques confirm the effectiveness of the approach.     

A Hybrid High-Order Method for the Steady Incompressible Navier–Stokes Problem

In this work we introduce and analyze a novel Hybrid High-Order method for the steady incompressible Navier–Stokes equations. The proposed method is inf-sup stable on general polyhedral meshes, supports arbitrary approximation orders, and is (relatively) inexpensive thanks to the possibility of statically condensing a subset of the unknowns at each nonlinear iteration. We show under general assumptions the existence of a discrete solution, which is also unique provided a data smallness condition is verified. Using a compactness argument, we prove convergence of the sequence of discrete solutions to minimal regularity exact solutions for general data. For more regular solutions, we prove optimal convergence rates for the energy-norm of the velocity and the \(L^2\)-norm of the pressure under a standard data smallness assumption. More precisely, when polynomials of degree \(k\ge 0\) at mesh elements and faces are used, both quantities are proved to converge as \(h^{k+1}\) (with h denoting the meshsize).     

Isospectral Domains for Discrete Elliptic Operators

Concerning the Laplace operator with homogeneous Dirichlet boundary conditions, the classical notion of isospectrality assumes that two domains are related when they give rise to the same spectrum. In two dimensions, non isometric, isospectral domains exist. It is not known however if all the eigenvalues relative to a specific domain can be preserved under suitable continuous deformation of its geometry. We show that this is possible when the 2D Laplacian is replaced by a finite dimensional version and the geometry is modified by respecting certain constraints. The analysis is carried out in a very small finite dimensional space, but it can be extended to more accurate finite-dimensional representations of the 2D Laplacian, with an increase of computational complexity. The aim of this paper is to introduce the preliminary steps in view of more serious generalizations.     

Cybersecurity investments with nonlinear budget constraints and conservation laws: variational equilibrium,marginal expected utilities,and Lagrange multipliers

In this paper, we propose a new cybersecurity investment supply chain game theory model, assuming that the demands for the product are known and fixed and, hence, the conservation law of each demand market is fulfilled. The model is a generalized Nash equilibrium model with nonlinear budget constraints for which we define the variational equilibrium, which provides us with a variational inequality formulation. We construct an equivalent formulation, enabling the analysis of the influence of the conservation laws and the importance of the associated Lagrange multipliers. We find that the marginal expected transaction utility of each retailer depends on this Lagrange multiplier and its sign. Finally, numerical examples with reported equilibrium product flows, cybersecurity investment levels, and Lagrange multipliers, along with individual firm vulnerability and network vulnerability, illustrate the obtained results.     

VRheab: a fully immersive motor rehabilitation system based on recurrent neural network

In this paper, a fully immersive serious game system that combines two Natural User Interfaces (NUIs) and a Head Mounted Display (HMD) to provide an interactive Virtual Environment (VE) for patient rehabilitation is proposed. Patients’ data are acquired in real-time by the NUIs, while by the HMD the VE is shown to them, thus allowing the interaction. A Long Short-Term Memory Recurrent Neural Network (LSTM-RNN), previously trained by healthy subjects (i.e., baseline), processes patients’ movements in real-time during the rehabilitation exercises to provide the degree of their performance. By comparing the functionalities of the proposed system with the ongoing state-of-the-art, it is worth noting that the reported fully immersive serious game system provides a concrete contribute to the current literature in terms of completeness and versatility. The results obtained by three rehabilitation exercises, chosen as reference case studies, performed on real patients affected by Parkinson’s disease have shown the effectiveness of the presented approach. Finally, the analysis of the feedbacks received by the therapists and patients who have used the system have highlighted remarkable results in terms of motivation, acceptance, and usability.     

Mo6S3Br6: An Anisotropic 2D Superatomic Semiconductor

Two‐dimensional (2D) van der Waals materials with in‐plane anisotropy are of great interest for directional transport of charge and energy, as exemplified by recent studies on black phosphorus and α‐phase molybdenum trioxide (α‐MO₃). Here, a layered van der Waals semiconductor with in‐plane anisotropy built upon the superatomic units of Mo₆S₃Br₆ is reported. This material possesses robust 2D characteristics with a direct gap of 1.64 eV, as determined by scanning tunneling spectroscopy and first‐principles calculations. Polarization‐dependent Raman spectroscopy measurement and density functional theory calculation reveal strong in‐plane anisotropy. These results suggest an effective strategy to explore anisotropic 2D electronic and optoelectronic properties from superatomic building blocks with multifunctionality, emergent properties, and hierarchical control.     

Liver and spleen enhancement after intravenous injection of carboxydextran magnetite: effect of dose,delay of imaging,and field strength in anex vivo model

It has been predicted that liver and spleen enhancement after administration of superparamagnetic contrast agents may be different, depending on the strength of the main magnetic field. With the use of anex vivo model, we investigated at 0.3, 0.5, and 1.5 T the effects on liver and spleen signal intensity of 5, 15, and 45 µmol/kg body weight of dextran magnetite (SHU 555A) in 54 rats. Nine rats served as controls. At different time delays since injection, the animals were killed, and after perfusion with saline, the liver, brain, and spleen were fixed in formalin. The specimens were embedded in an agar gel matrix and imaged with inversion recovery T1-weighted, proton density spin echo, and T2*-weighted gradient recalled echo (GRE) sequences. At each magnetic field strength, peak liver and spleen signal loss increased with increasing dose of the contrast medium. Signal loss was significantly more conspicuous after a dose of 15 than 5 µmol/kg body weight, but not after a dose of 45 compared with 15 µmol/kg. No signal change was observed in the brain. GRE images showed higher enhancement than proton density-weighted spin echo and inversion recovery images but were noisier. The enhancement showed a plateau between 30 min and 24 hours. Only the signal decrease of the liver after a low dose of contrast medium on GRE images was significantly higher (p<0.01) at 1.5 than at 0.5 and 0.3 T. Other differences in respect to the field strength were less significant (p<0.05) or nonsignificant. Differences in the spleen enhancement were nonsignificant. SHU 555A at a dose of 15 µmol/kg is an efficient intracellular contrast agent for liver and spleen at low, mid, and high field strength. Proton density spin echo images are probably the sequence of choice to exploit SHU 555A contrast effects and a wide time window for imaging after its intravenous injection does exist.