5 research outputs found
Joint source and relay optimization for parallel MIMO relay networks
No full textIn this article, we study the optimal structure of the source precoding matrix and the relay amplifying matrices for multiple-input multiple-output (MIMO) relay communication systems with parallel relay nodes. Two types of receivers are considered at the destination node: (1) The linear minimal mean-squared error (MMSE) receiver; (2) The nonlinear decision feedback equalizer based on the minimal MSE criterion. We show that for both receiver schemes, the optimal source precoding matrix and the optimal relay amplifying matrices have a beamforming structure. Using such optimal structure, joint source and relay power loading algorithms are developed to minimize the MSE of the signal waveform estimation at the destination. Compared with existing algorithms for parallel MIMO relay networks, the proposed joint source and relay beamforming algorithms have significant improvement in the system bit-error-rate performance
Joint source and relay design for MIMO multi-relay systems using projected gradient approach
No full textIn this paper, we develop the optimal source precoding matrix and relay amplifying matrices for non-regenerative multiple-input multiple-output (MIMO) relay communication systems with parallel relay nodes using the projected gradient (PG) approach. We show that the optimal relay amplifying matrices have a beamforming structure. Exploiting the structure of relay matrices, an iterative joint source and relay matrices optimization algorithm is developed to minimize the mean-squared error (MSE) of the signal waveform estimation at the destination using the PG approach. The performance of the proposed algorithm is demonstrated through numerical simulations
Thinking Out of the Blocks:Holochain for Distributed Security in IoT Healthcare
No full textThe Internet-of-Things (IoT) is an emerging technology that connects and integrates a massive number of smart physical devices with virtual objects operating in diverse platforms through the internet. Due to massive size and physical spread of many applications such as smart healthcare, IoT is increasingly implemented in distributed setting. This distributed nature of implementation of the entities connected to the IoT networks are exposed to an unprecedented level of privacy and security threats. This is particularly severe for IoT healthcare system as it involves huge volume of sensitive and personal data. Although blockchain has posed to be the solution in this scenario thanks to its inherent distributed ledger technology (DLT), it suffers from a major drawback of rapidly increasing storage and computation requirements with the increase in network size which makes its implementation impractical. This paper proposes a holochain-based security and privacy-preserving framework for IoT healthcare systems that overcomes the scalability challenge and is particularly suited for resource constrained IoT scenarios. Through thorough analysis and performance results, we have demonstrated that the holochain based IoT healthcare solution outperforms blockchain based solution in terms of resource requirements while ensuring appropriate level of privacy and security.</p
Radiological risks assessment of building materials ingredients: Palm oil clinker and fuel ash
No full textTechnical benefits relevant to the use of palm oil clinker (POC) and fuel ash (POFA) in building materials has been well documented. However, the radiological health hazards caused by the incorporation of POC and POFA as an ingredient of building materials have not been studied so far. The radioactivity levels were measured by γ-ray spectrometry using hyper-pure germanium (HPGe) detector. The activity concentration of 226 Ra and 232 Th in POC and POFA was found to be in the ranges of 5.56 ± 0.23 to 9.03 ± 0.21 and 4.21 ± 0.03 to 7.98 ± 0.19 Bq kg −1 , respectively, and these values were lower than the world average values of 50 Bq kg −1 for building materials. The 40 K value was within the range of 413.01 ± 1.78 to 604.66 ± 2.18 Bq kg −1 . Several radiological parameters and hazard indices, i.e. radium equivalent activity, absorbed dose rate and annual effective dose etc. were calculated for the evaluation of the potential radiological hazards. The obtained values fall within the recommended limit set by various international organizations. Since the activity levels of 226 Ra, 232 Th and 40 K in POC and POFA were significantly lower than the corresponding literature data for other ingredients of building materials, it indicates that POC and POFA are safe to be used in concrete construction. © The Author(s) 2018
Exclusive Electroproduction off the Neutron in Deuterium in the Resonance Region
No full textNew results for the exclusive and quasi-free cross sections off neutrons
bound in deuterium are presented
over a wide final state hadron angle range with a kinematic coverage of the
invariant mass () up to 1.825 GeV and the virtual photon four-momentum
transfer squared () from 0.4 to 1.0 GeV. The exclusive structure
functions were extracted and their Legendre moments were obtained.
Final-state-interaction contributions have been kinematically separated from
the extracted quasi-free cross sections off bound neutrons solely based on the
analysis of the experimental data. These new results will serve as long-awaited
input for phenomenological analyses to extract the evolution of
previously unavailable electroexcitation amplitudes and to
improve state-of-the-art models of neutrino scattering off nuclei by augmenting
the already available results from free protons.Comment: The author list has been update
