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The authors propose an optimal resource allocation (RA) scheme for wireless multi-destination relay systems with orthogonal frequency division multiplexing (OFDM) modulation. The authors work is different in that they consider a practical downlink OFDM-based relay network, where a relay is used to help the source (base station) communicate with multiple out-of-range destinations (users), rather than a single destination (user) as assumed in most previous work. The proposed optimal RA scheme consists of subchannel allocation (SA), subchannel pairing and joint source-relay power allocation (PA). In particular, it is shown that both SA and joint source-relay PA play a dominant role in the three steps of RA. It is also demonstrated that the shorter the distance between the source and the relay, the more impact of multiuser diversity on the system capacity. By employing SA and joint source-relay PA only, a near-optimal performance can be achieved. This work can be extended to the multi-hop, multi-relay and multi-destination uplink/downlink OFDM system. [ABSTRACT FROM AUTHOR]

In this study, hybrid excitation doubly salient machines (HEDSMs) with parallel excitation structures are introduced. The three types of main poles in the HEDSMs are described and researched, respectively. A 30/20-pole HEDSM is analysed by the magnetic circuit means. Regulation performance of the air-gap fluxes of different main poles is presented. The expression of the total air-gap flux shows the ideal linear relationship between the total air-gap flux and the field excitation ampere-turns. The finite element analysis also verifies the perfect effect of the field control. And the flux line plots and no-load electromagnetic force (EMF) waveforms are presented. The experimental EMF waveforms and no-load characteristic curve are coincident with the simulation results. [ABSTRACT FROM AUTHOR]

To reduce the computational load of the ensemble Kalman filter while maintaining its efficacy, an optimisation algorithm based on the generalised eigenvalue decomposition method is proposed for identifying the most informative measurement subspace. When the number of measurements is large, the proposed algorithm can be used to make an effective trade-off between computational complexity and estimation accuracy. [ABSTRACT FROM AUTHOR]

By replacing a classical channel with a quantum one during quantum teleportation, a quantum key agreement protocol is presented. The key bits are determined only by the random measurement outcomes and are independent of the states transmitted over the channel. [ABSTRACT FROM AUTHOR]