118 research outputs found
Cloud Computing and Big Data for Oil and Gas Industry Application in China
The oil and gas industry is a complex data-driven industry with compute-intensive, data-intensive and business-intensive features. Cloud computing and big data have a broad application prospect in the oil and gas industry. This research aims to highlight the cloud computing and big data issues and challenges from the informatization in oil and gas industry. In this paper, the distributed cloud storage architecture and its applications for seismic data of oil and gas industry are focused on first. Then,cloud desktop for oil and gas industry applications are also introduced in terms of efficiency, security and usability. Finally, big data architecture and security issues of oil and gas industry are analyzed. Cloud computing and big data architectures have advantages in many aspects, such as system scalability, reliability, and serviceability. This paper also provides a brief description for the future development of Cloud computing and big data in oil and gas industry. Cloud computing and big data can provide convenient information sharing and high quality service for oil and gas industry
Beamforming Design for IRS-and-UAV-aided Two-way Amplify-and-Forward Relay Networks
As a promising solution to improve communication quality, unmanned aerial
vehicle (UAV) has been widely integrated into wireless networks. In this paper,
for the sake of enhancing the message exchange rate between User1 (U1) and
User2 (U2), an intelligent reflective surface (IRS)-and-UAV- assisted two-way
amplify-and-forward (AF) relay wireless system is proposed, where U1 and U2 can
communicate each other via a UAV-mounted IRS and an AF relay. Besides, an
optimization problem of maximizing minimum rate is casted, where the variables,
namely AF relay beamforming matrix and IRS phase shifts of two time slots, need
to be optimized. To achieve a maximum rate, a low-complexity alternately
iterative (AI) scheme based on zero forcing and successive convex approximation
(LC-ZF-SCA) algorithm is put forward, where the expression of AF relay
beamforming matrix can be derived in semi-closed form by ZF method, and IRS
phase shift vectors of two time slots can be respectively optimized by
utilizing SCA algorithm. To obtain a significant rate enhancement, a
high-performance AI method based on one step, semidefinite programming and
penalty SCA (ONS-SDP-PSCA) is proposed, where the beamforming matrix at AF
relay can be firstly solved by singular value decomposition and ONS method, IRS
phase shift matrices of two time slots are optimized by SDP and PSCA
algorithms. Simulation results present that the rate performance of the
proposed LC-ZF-SCA and ONS-SDP-PSCA methods surpass those of random phase and
only AF relay. In particular, when total transmit power is equal to 30dBm, the
proposed two methods can harvest more than 68.5% rate gain compared to random
phase and only AF relay. Meanwhile, the rate performance of ONS-SDP-PSCA method
at cost of extremely high complexity is superior to that of LC-ZF-SCA method
Precoding and Beamforming Design for Intelligent Reconfigurable Surface-Aided Hybrid Secure Spatial Modulation
Intelligent reflecting surface (IRS) is an emerging technology for wireless
communication composed of a large number of low-cost passive devices with
reconfigurable parameters, which can reflect signals with a certain phase shift
and is capable of building programmable communication environment. In this
paper, to avoid the high hardware cost and energy consumption in spatial
modulation (SM), an IRS-aided hybrid secure SM (SSM) system with a hybrid
precoder is proposed. To improve the security performance, we formulate an
optimization problem to maximize the secrecy rate (SR) by jointly optimizing
the beamforming at IRS and hybrid precoding at the transmitter. Considering
that the SR has no closed form expression, an approximate SR (ASR) expression
is derived as the objective function. To improve the SR performance, three IRS
beamforming methods, called IRS alternating direction method of multipliers
(IRS-ADMM), IRS block coordinate ascend (IRS-BCA) and IRS semi-definite
relaxation (IRS-SDR), are proposed. As for the hybrid precoding design,
approximated secrecy rate-successive convex approximation (ASR-SCA) method and
cut-off rate-gradient ascend (COR-GA) method are proposed. Simulation results
demonstrate that the proposed IRS-SDR and IRS-ADMM beamformers harvest
substantial SR performance gains over IRS-BCA. Particularly, the proposed
IRS-ADMM and IRS-BCA are of low-complexity at the expense of a little
performance loss compared with IRS-SDR. For hybrid precoding, the proposed
ASR-SCA performs better than COR-GA in the high transmit power region.Comment: 14pages,8figure
Three Efficient Beamforming Methods for Hybrid IRS plus AF Relay-aided Metaverse
In this paper, an optimization problem is formulated to maximize
signal-to-noise ratio (SNR) by jointly optimizing the beamforming matrix at AF
relay and the reflecting coefficient matrices at IRS subject to the constraints
of transmit power budgets at the base station (BS)/AF relay/hybrid IRS and that
of unit-modulus for passive IRS phase shifts. To achieve high rate performance
and extend the coverage range, a high-performance method based on semidefinite
relaxation and fractional programming (HP-SDR-FP) algorithm is presented. Due
to its extremely high complexity, a low-complexity method based on successive
convex approximation and FP (LC-SCA-FP) algorithm is put forward. To further
reduce the complexity, a lower-complexity method based on whitening filter,
general power iterative and generalized Rayleigh-Ritz (WF-GPI-GRR) is proposed,
where different from the above two methods, it is assumed that the amplifying
coefficient of each active IRS element is equal, and the corresponding
analytical solution of the amplifying coefficient can be obtained according to
the transmit powers at AF relay and hybrid IRS. Simulation results show that
the proposed three methods can greatly improve the rate performance compared to
the existing technology-aided metaverse, such as the passive IRS plus AF
relay-aided metaverse and only AF relay-aided metaverse. In particular, a 50.0%
rate gain over the existing technology-aided metaverse is approximately
achieved in the high power budget region of hybrid IRS. Moreover, it is
verified that the proposed three efficient beamforming methods have an
increasing order in rate performance: WF-GPI-GRR, LC-SCA-FP and HP-SDR-FP
Two Rapid Power Iterative DOA Estimators for UAV Emitter Using Massive/Ultra-massive Receive Array
To provide rapid direction finding (DF) for unmanned aerial vehicle (UAV)
emitter in future wireless networks, a low-complexity direction of arrival
(DOA) estimation architecture for massive multiple input multiple output (MIMO)
receiver arrays is constructed. In this paper, we propose two strategies to
address the extremely high complexity caused by eigenvalue decomposition of the
received signal covariance matrix. Firstly, a rapid power-iterative rotational
invariance (RPI-RI) method is proposed, which adopts the signal subspace
generated by power iteration to gets the final direction estimation through
rotational invariance between subarrays. RPI-RI makes a significant complexity
reduction at the cost of a substantial performance loss. In order to further
reduce the complexity and provide a good directional measurement result, a
rapid power-iterative Polynomial rooting (RPI-PR) method is proposed, which
utilizes the noise subspace combined with polynomial solution method to get the
optimal direction estimation. In addition, the influence of initial vector
selection on convergence in the power iteration is analyzed, especially when
the initial vector is orthogonal to the incident wave. Simulation results show
that the two proposed methods outperform the conventional DOA estimation
methods in terms of computational complexity. In particular, the RPIPR method
achieves more than two orders of magnitude lower complexity than conventional
methods and achieves performance close to CRLB. Moreover, it is verified that
the initial vector and the relative error have a significant impact on the
performance of the computational complexity
Restoration of Critical-Sized Defects in the Rabbit Mandible Using Autologous Bone Marrow Stromal Cells Hybridized with Nano- β
Nano-β-tricalcium phosphate/collagen (n-β-TCP/Col) is considered with good osteoconductivity. However, the therapeutic effectiveness of n-β-TCP/Col scaffolds in combination with autologous bone marrow stromal cells (BMSCs) remains to be elucidated for the repair of critical-sized bone defects. In this study, we found that n-β-TCP/Col scaffolds exhibited high biocompatibility in vitro. The introduction of BMSCs expanded in vitro to the scaffolds dramatically enhanced their efficiency to restore critical-sized bone defects, especially during the initial stage after implantation. Collectively, these results suggest that autologous BMSCs in n-β-TCP/Col scaffolds have the potential to be applied in bone tissue engineering
CD180 Ligation Inhibits TLR7- and TLR9-Mediated Activation of Macrophages and Dendritic Cells Through the Lyn-SHP-1/2 Axis in Murine Lupus
Activation of TLR7 and TLR9 by endogenous RNA- or DNA-containing ligands, respectively, can lead to hyper-activation of immune cells, including macrophages and DCs, subsequently contributes to the pathogenesis of SLE. CD180, a TLR-like protein, is specifically involved in the development and activation of immune cells. Our previous study and others have reported that CD180-negative B cells are dramatically increased in SLE patients and responsible for the production of auto-antibodies. However, the mode of CD180 expression on macrophages and DCs in SLE remains unclear and the role of CD180 on regulating TLR7- and TLR9-mediated activation of macrophages and DCs are largely unknown. In the present study, we found that the percentages of CD180-negative macrophages and DCs were both increased in SLE patients and lupus-prone MRL/lpr mice compared with healthy donors and wild-type mice, respectively. Notably, ligation of CD180 significantly inhibited the activation of TLR7 and TLR9 signaling pathways in macrophages and DCs through the Lyn-SHP-1/2 axis. What's more, injection of anti-CD180 Ab could markedly ameliorate the lupus-symptoms of imiquimod-treated mice and lupus-prone MRL/lpr mice through inhibiting the activation of macrophages and DCs. Collectively, our results highlight a critical role of CD180 in regulating TLR7- and TLR9-mediated activation of macrophages and DCs, hinting that CD180 can be regarded as a potential therapeutic target for SLE treatment
Genome-wide identification and analysis of heterotic loci in three maize hybrids
Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear in many crops. Here, we present a large-scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield-related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete–incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the major causes of strong heterosis in these hybrids. Follow-up studies for 17 heterotic loci in an independent experiment using 2225 F2 individuals suggest most heterotic effects are roughly stable between environments with a small variation. Candidate gene analysis for one major heterotic locus (ub3) in maize implies that there may exist some common genes contributing to crop heterosis. These results provide a community resource for genetics studies in maize and new implications for heterosis in plants
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