4,957 research outputs found

    Detect-and-forward relaying aided cooperative spatial modulation for wireless networks

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    A novel detect-and-forward (DeF) relaying aided cooperative SM scheme is proposed, which is capable of striking a flexible tradeoff in terms of the achievable bit error ratio (BER), complexity and unequal error protection (UEP). More specifically, SM is invoked at the source node (SN) and the information bit stream is divided into two different sets: the antenna index-bits (AI-bits) as well as the amplitude and phase modulation-bits (APM-bits). By exploiting the different importance of the AI-bits and the APM-bits in SM detection, we propose three low-complexity, yet powerful relay protocols, namely the partial, the hybrid and the hierarchical modulation (HM) based DeF relaying schemes. These schemes determine the most appropriate number of bits to be re-modulated by carefully considering their potential benefits and then assigning a specific modulation scheme for relaying the message. As a further benefit, the employment of multiple radio frequency (RF) chains and the requirement of tight inter-relay synchronization (IRS) can be avoided. Moreover, by exploiting the benefits of our low-complexity relaying protocols and our inter-element interference (IEI) model, a low-complexity maximum-likelihood (ML) detector is proposed for jointly detecting the signal received both via the source-destination (SD) and relay-destination (RD) links. Additionally, an upper bound of the BER is derived for our DeF-SM scheme. Our numerical results show that the bound is asymptotically tight in the high-SNR region and the proposed schemes provide beneficial system performance improvements compared to the conventional MIMO schemes in an identical cooperative scenario.<br/

    Thermal conductivity of textile reinforcements for composites

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    Thermal conductivity data for dry carbon fibre fabrics are required for modelling heat transfer during composites manufacturing processes; however, very few published data are available. This article reports in-plane and through-thickness thermal conductivities measured as a function of fibre volume fraction ( Vf) for non-crimp and twill carbon reinforcement fabrics, three-dimensional weaves and reinforcement stacks assembled with one-sided carbon stitch. Composites made from these reinforcements and glass fibre fabrics are also measured. Clear trends are observed and the effects of Vf, de-bulking and vacuum are quantified along with orthotropy ratios. Limited differences between the conductivity of dry glass and carbon fibre fabrics in the through-thickness direction are reported. An unexpected trend in the relationship between that quantity and Vf is explained summarily through simple simulations

    Observer-based networked control for continuous-time systems with random sensor delays

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    This is the post print version of the article. The official published version can be obtained from the link - Copyright 2009 Elsevier LtdThis paper is concerned with the networked control system design for continuous-time systems with random measurement, where the measurement channel is assumed to subject to random sensor delay. A design scheme for the observer-based output feedback controller is proposed to render the closed-loop networked system exponentially mean-square stable with H∞ performance requirement. The technique employed is based on appropriate delay systems approach combined with a matrix variable decoupling technique. The design method is fulfilled through solving linear matrix inequalities. A numerical example is used to verify the effectiveness and the merits of the present results.This paper was not presented at any IFAC meeting. This paper was recommended for publication in revised form by Associate Editor George Yin under the direction of Editor Ian R. Petersen. This work was supported in part by the Royal Society of the UK, the National Natural Science Foundation of China (60774047, 60674055) and the Taishan Scholar Programs Foundation of Shandong Province, China

    Phase rotation-based precoding for spatial modulation systems

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    In this study, the authors investigate the benefits of phase-rotation-assisted precoding (PRP) technique in spatial modulation (SM) systems, which are based on maximum free distance dmin. First, a closed-form solution of the maximumdmin PRP matrix is derived for the scenario of having two transmit antennas (Nt = 2). Moreover, two numerical methods are proposed for dealing with the case of Nt &gt; 2. The complexity of the proposed algorithms is presented. The authors simulation results show that the proposed PRP algorithms provide beneficial bit error ratio performance improvements compared with both the conventional SM and with the existing adaptive S

    (E)-N′-(4-Hy­droxy­benzyl­idene)-3-nitro­benzohydrazide

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    The mol­ecule of the title compound, C14H11N3O4, assumes an E conformation about the C=N double bond. The benzene rings form a dihedral angle of 3.9 (2)°. The crystal structure is stabilized by N—H⋯O, O—H⋯N, O—H⋯O and C—H⋯O hydrogen bonds, forming layers parallel to (101). In addition, intra­layer π–π stacking inter­actions [centroid–centroid distance = 3.635 (2) Å] are observed

    N′-[(2-Methoxynaphthalen-1-yl)methyl­idene]-4-methyl­benzohydrazide

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    In the title compound, C20H18N2O2, the mean planes of the naphthyl system and the benzene ring form a dihedral angle of 88.48 (10)°. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into C(4) chains, which propagate along the b-axis direction

    2-Fluoro-N′-[(2-hydroxynaphthalen-1-yl)methylidene]benzohydrazide

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    In the title mol­ecule, C18H13FN2O2, the hy­droxy group is involved in an intra­molecular O—H⋯N hydrogen bond. The naphthyl ring system and the benzene ring form a dihedral angle of 31.0 (2)°. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into chains propagating in [101]

    HDX-guided EPR spectroscopy to interrogate membrane protein dynamics

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    This project was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) grant (BB/S018069/1) to C.P., who also acknowledges support from the Wellcome Trust (WT) (219999/Z/19/Z) and the Chinese Scholarship Council (CSC) in the form of studentships for B.J.L. and B.W., respectively. A.N.C. is a Sir Henry Dale Fellow jointly funded by the WT and the Royal Society (220628/Z/20/Z). Funding from the BBSRC (BB/M012573/1) enabled the purchase of mass spectrometry equipment.Solvent accessibilities of and distances between protein residues measured by pulsed-EPR approaches provide high-resolution information on dynamic protein motions. We describe protocols for the purification and site-directed spin labeling of integral membrane proteins. In our protocol, peptide-level HDX-MS is used as a precursor to guide single-residue resolution ESEEM accessibility measurements and spin labeling strategies for EPR applications. Exploiting the pentameric MscL channel as a model, we discuss the use of cwEPR, DEER/PELDOR, and ESEEM spectroscopies to interrogate membrane protein dynamics. For complete details on the use and execution of this protocol, please refer to Wang et al. (2022).Publisher PDFPeer reviewe

    Analysis and synthesis of randomly switched systems with known sojourn probabilities

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    In this paper, a new approach is proposed and investigated for the stability analysis and stabilizing controller design of randomly switched linear discrete systems. The approach is based on sojourn probabilities and it is assumed that these probabilities are known a prior. A new Lyapunov functional is constructed and two main theorems are proved in this paper. Theorem 1 gives a sufficient condition for a switched system with known sojourn probabilities to be mean square stable. Theorem 2 gives a sufficient condition for the design of a stabilizing controller. The applications of these theorems and the corresponding corollary and lemma are demonstrated by three numerical examples. Finally, some future research is proposed

    Characterization and Optical Properties of the Single Crystalline SnS Nanowire Arrays

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    The SnS nanowire arrays have been successfully synthesized by the template-assisted pulsed electrochemical deposition in the porous anodized aluminum oxide template. The investigation results showed that the as-synthesized nanowires are single crystalline structures and they have a highly preferential orientation. The ordered SnS nanowire arrays are uniform with a diameter of 50 nm and a length up to several tens of micrometers. The synthesized SnS nanowires exhibit strong absorption in visible and near-infrared spectral region and the direct energy gapEgof SnS nanowires is 1.59 eV
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