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Low complexity robust adaptive beamforming for general-rank signal model with positive semidefinite constraint

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Frontiers of Information Technology & Electronic Engineering 2016年第11期17卷 1245-1252页

作者： yu-tang zhu Yong-bo ZHAO Jun LIU Peng-lang SHUI National Laboratory of Radar Signal Processing Xidian University

We propose a low complexity robust beamforming method for the general-rank signal model, to combat against mismatches of the desired signal array response and the received signal covariance matrix. The proposed beamformer not only considers the norm bounded uncertainties in the desired and received signal covariance matrices, but also includes an additional positive semidefinite constraint on the desired signal covariance matrix. Based on the worst-case performance optimization criterion, a computationally simple closed-form weight vector is obtained. Simulation results verify the validity and robustness of the proposed beamforming method.

关键词： Beamforming General-rank Low complexity Positive semidefinite(PSD) constraint Model mismatches

Spinal Vertebral Fracture Detection and Fracture Level Assessment Based on Deep Learning

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Computers, Materials & Continua 2024年第4期79卷 1377-1398页

作者： yuhang Wang Zhiqin He Qinmu Wu Tingsheng Lu yu tang Maoyun zhu The Electrical Engineering College Guizhou UniversityGuiyang550025China Guizhou Provincial Orthopedics Hospital Guiyang550025China

This paper addresses the common orthopedic trauma of spinal vertebral fractures and aims to enhance doctors’diagnostic ***,a deep-learning-based automated diagnostic systemwithmulti-label segmentation is proposed to recognize the condition of vertebral *** whole spine Computed Tomography(CT)image is segmented into the fracture,normal,and background using U-Net,and the fracture degree of each vertebra is evaluated(Genant semi-qualitative evaluation).The main work of this paper includes:First,based on the spatial configuration network(SCN)structure,U-Net is used instead of the SCN feature extraction *** attention mechanismandthe residual connectionbetweenthe convolutional layers are added in the local network(LN)*** filtering is added in the global network(GN)stage,and each layer of the LN decoder feature map is filtered separately using dot product,and the filtered features are re-convolved to obtain the GN output ***,a network model with improved SCN(M-SCN)helps automatically localize the center-of-mass position of each vertebra,and the voxels around each localized vertebra were clipped,eliminating a large amount of redundant information(e.g.,background and other interfering vertebrae)and keeping the vertebrae to be segmented in the center of the *** segmentation of the clipped portion was subsequently performed using *** paper uses VerSe’19,VerSe’20(using only data containing vertebral fractures),and private data(provided by Guizhou Orthopedic Hospital)for model training and *** with the original SCN network,the M-SCN reduced the prediction error rate by 1.09%and demonstrated the effectiveness of the improvement in ablation *** the vertebral segmentation experiment,the Dice Similarity Coefficient(DSC)index reached 93.50%and the Maximum Symmetry Surface Distance(MSSD)index was 4.962 mm,with accuracy and recall of 95.82%and 91.73%,*** vertebrae w

关键词： Deep learning vertebral fracture detection medical image processing

Characteristic Analysis of Power Oscillations Caused by Disharmony Among Voltage-source-controlled Units in Three-terminal Local Power Grid

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1295-1308页

作者： Qiyi yu Yi tang School of Electrical Engineering Southeast UniversityNanjing 210018China

Previous studies have demonstrated that disharmo-ny among voltage-source-controlled units(VSCUs)may occur on an alternating current(AC)transmission or distribution line under steady-state operating conditions(SSOCs)or quasi-static operating conditions(QSSOCs).As the studies on frequency dis-harmony have been expanded to multiple disharmonized vS-CUs in the local power grid,its adverse effects on AC lines and equivalent load(EL)at the bus without active voltage control ability(non-active bus)need to be investigated ***-ering the locality of disharmony and common topological con-nections among VSCUs,this paper adopts a Y-type three-termi-nal local power grid(LPG)as the research *** dishar-mony among the three VSCUs is ***,for the load at non-active bus,the formulas for single-phase instantaneous voltage,load current,load power,as well as average power un-der disharmony operating conditions(DOCs)are *** characteristic indicators of the above electrical quantities are defined,which can measure the amplification and reduction de-grees of the above electrical quantities before and after ***,for the line directly connected to VSCUs,the formulas for single-phase instantaneous line current and power and the average power under DOCs are *** character-istic indicators of power flow are defined,which can be used to quantify the peak amplification impact of oscillation before and after ***,the case study on the Y-type three-terminal LPG under the single-disharmony and the multi-dis-harmony switching scenarios indicates that the long-period pow-er oscillation caused by disharmony may occur in the load flow at the non-active bus and the line *** oscillation causes a serious decrease in load capability and a significant amplifica-tion of the peak of line power oscillation.

关键词： New power system power oscillation disharmony voltage-source-controlled unit(VSCU) characteristic analysis

Topological Stability and Entropy for Certain Set-valued Maps

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Acta Mathematica Sinica,English Series 2024年第4期40卷 962-984页

作者： yu ZHANG yu Jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the dynamics(including shadowing property,expansiveness,topological stability and entropy)of several types of upper semi-continuous set-valued maps are mainly considered from differentiable dynamical systems points of *** is shown that(1)if f is a hyperbolic endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has theε-shadowing property,and moreover,if f is an expanding endomorphism then there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has the Lipschitz shadowing property;(2)when a set-valued map F is generated by finite expanding endomorphisms,it has the shadowing property,and moreover,if the collection of the generators has no coincidence point then F is expansive and hence is topologically stable;(3)if f is an expanding endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that h(F_(f,U,ε))=h(f);(4)when F is generated by finite expanding endomorphisms with no coincidence point,the entropy formula of F is ***,the dynamics of the set-valued maps based on discontinuous maps on the interval are also considered.

关键词： Set-valued map orbit space hyperbolic endomorphism perturbation shadowing expansiveness topological stability entropy

Photocatalytic oxidation of methane to methanol over zinc titanate supported silver catalysts

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Journal of Rare Earths 2024年第5期42卷 899-906,I0004页

作者： yuyan Gan Jinbi Huang Qian Lv Yanru Li Lizhi Wu yu tang yuanxing Fang Pengfei zhu Li Tan Institute of Molecule Catalysis and In-Situ/Operando Studies State Key Laboratory of Photocatalysis on Energy and EnvironmentCollege of ChemistryFuzhou UniversityFuzhou350108China School of Environmental Science and Engineering Shaanxi University of Science and TechnologyXi'an 70021China

The direct activation of methane under mild condition to achieve highly selective of oxygenates is a challenging *** this study,a well dispersed silver supported ZnTiO_(3) catalyst was prepared to achieve selective preparation of methanol from methane and water under mild condition.X-ray diffraction,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations demonstrate that silver species are uniformly dispersed on ZnTiO_(3) surface in the form of metallic silver *** photoelectric characterizations reveal that the addition of silver species enhances light absorption and promotes charge separation of the *** the reaction conditions of 50℃and 3 MPa,the methanol is obtained as the only liquid product over the designed Ag/ZnTiO_(3) catalyst under light *** this photocatalytic process,the holes generated by ZnTiO_(3) activate water to produce intermediate·OH,which further reacts with methane to synthesize *** silver species as co-catalysts extend the light absorption range of ZnTiO_(3) as well as promote charge separation.

关键词： Photocatalytic Methane oxidation Zinc titanate Silver Methanol

Data-driven modeling on anisotropic mechanical behavior of brain tissue with internal pressure

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Defence Technology（防务技术） 2024年第3期33卷 55-65页

作者： Zhiyuan tang yu Wang Khalil I.Elkhodary Zefeng yu Shan tang Dan Peng State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of Technology116023DalianPR China The Department of Mechanical Engineering The American University in CairoNew Cairo11835Egypt Department of Neurology The Second Hospital of Dalian Medical UniversityDalian116023PR China

Brain tissue is one of the softest parts of the human body,composed of white matter and grey *** mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain ***,traumatic brain injury(TBI)and various brain diseases are also greatly influenced by the brain's mechanical *** white matter or grey matter,brain tissue contains multiscale structures composed of neurons,glial cells,fibers,blood vessels,etc.,each with different mechanical *** such,brain tissue exhibits complex mechanical behavior,usually with strong nonlinearity,heterogeneity,and directional *** a constitutive law for multiscale brain tissue using traditional function-based approaches can be very ***,this paper proposes a data-driven approach to establish the desired mechanical model of brain *** focus on blood vessels with internal pressure embedded in a white or grey matter matrix material to demonstrate our *** matrix is described by an isotropic or anisotropic nonlinear elastic model.A representative unit cell(RUC)with blood vessels is built,which is used to generate the stress-strain data under different internal blood pressure and various proportional displacement loading *** generated stress-strain data is then used to train a mechanical law using artificial neural networks to predict the macroscopic mechanical response of brain tissue under different internal ***,the trained material model is implemented into finite element software to predict the mechanical behavior of a whole brain under intracranial pressure and distributed body *** with a direct numerical simulation that employs a reference material model,our proposed approach greatly reduces the computational cost and improves modeling *** predictions made by our trained model demonstrate sufficient ***,we find that the level of internal blood pressur

关键词： Data driven Constitutive law Anisotropy Brain tissue Internal pressure

Deep-reinforcement-learning-based UAV autonomous navigation and collision avoidance in unknown environments

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Chinese Journal of Aeronautics 2024年第3期37卷 237-257页

作者： Fei WANG Xiaoping zhu Zhou ZHOU Yang tang School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

In some military application scenarios,Unmanned Aerial Vehicles(UAVs)need to perform missions with the assistance of on-board cameras when radar is not available and communication is interrupted,which brings challenges for UAV autonomous navigation and collision *** this paper,an improved deep-reinforcement-learning algorithm,Deep Q-Network with a Faster R-CNN model and a Data Deposit Mechanism(FRDDM-DQN),is proposed.A Faster R-CNN model(FR)is introduced and optimized to obtain the ability to extract obstacle information from images,and a new replay memory Data Deposit Mechanism(DDM)is designed to train an agent with a better *** training,a two-part training approach is used to reduce the time spent on training as well as retraining when the scenario *** order to verify the performance of the proposed method,a series of experiments,including training experiments,test experiments,and typical episodes experiments,is conducted in a 3D simulation *** results show that the agent trained by the proposed FRDDM-DQN has the ability to navigate autonomously and avoid collisions,and performs better compared to the FRDQN,FR-DDQN,FR-Dueling DQN,YOLO-based YDDM-DQN,and original FR outputbased FR-ODQN.

关键词： Faster R-CNN model Replay memory Data Deposit Mechanism(DDM) Two-part training approach Image-based Autonomous Navigation and Collision Avoidance(ANCA) Unmanned Aerial Vehicle(UAV)

Bi-doped carbon quantum dots functionalized liposomes with fluorescence visualization imaging for tumor diagnosis and treatment

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Chinese Chemical Letters 2024年第4期35卷 414-419页

作者： Peide zhu Yangjia Liu Yaoyao tang Siqi zhu Xinyang Liu Lei Yin Quan Liu Zhiqiang yu Quan Xu Dixian Luo Juncheng Wang State Key Laboratory of Heavy Oil Processing China University of Petroleum-BeijingBeijing 102249China Department of Laboratory Medicine Dongguan Institute of Clinical Cancer ResearchAffiliated Dongguan HospitalSouthern Medical UniversityDongguan 523058China Department of Laboratory Medicine Huazhong University of Science and Technology Union Shenzhen Hospital(Nanshan Hospital)Shenzhen 518052China Institute of Stomatology First Medical CenterChinese PLA General HospitalBeijing 100853China

Liposomes are one of the significant classes of antitumor nanomaterials and the most successful nanomedicine drugs in clinical translation. However, it is difficult to accurately reveal liposome delivery modes and drug release rates at different p H values to assess the biodistribution and drug delivery pathways in vivo. Here, we established a strategy to integrate Bi-doped carbon quantum dots(CQDs)with liposomes to produce fluorescence visualization and therapeutic effects, namely lipo/Bi-doped ***/Bi-doped CQDs show good water solubility and physicochemical properties, which can be used for in vitro labeling of colon cancer(CT26) cells and in vivo imaging localization tracking tumors for monitoring. Simultaneously, thanks to the excellent p H sensitivity and ion doping characteristic of Bi-doped CQDs, lipo/Bi-doped CQDs can be used to reveal the drug release rate of liposomes at different p H values and exhibit potential effects in vivo antitumor therapy.

关键词： Bi-doped CQDs Lipo/Bi-doped CQDs pH sensitivity In vitro/in vivo imaging Diagnosis and treatment integration

D-A-D-structured boron-dipyrromethene with aggregation-induced enhanced phototherapeutic efficiency for near-infrared fluorescent and photoacoustic imaging-guided synergistic photodynamic and photothermal cancer therapy

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Chinese Chemical Letters 2024年第10期35卷 325-330页

作者： Xuejian Xing Pan zhu E Pang Shaojing Zhao yu tang Zheyu Hu Quchang Ouyang Minhuan Lan Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety College of Chemistry and Chemical Engineering Central South University School of Chemistry and Chemical Engineering Neijiang Normal University Medical Department of Breast Cancer Hunan Cancer Hospital Medical Department of Breast Cancer The Affiliated Cancer Hospital of Xiangya School of Medicine Central South University

Clinical phototheranostic agents suffer from low absorption in near-infrared（NIR） region, decreasing singlet oxygen quantum yield（1O2QY） caused by aggregation in water, and low photothermal conversion efficiency（PCE）, all of which are factors weakening their phototheranostic efficacy. Herein, we designed and synthesized a donor-acceptor-donor（D-A-D） structured boron-dipyrromethene derivative（B-2TPA） which exhibited NIR absorption and fluorescence. After being encapsulated in amphiphilic distearoyl phosphoethanolamine polyethyleneglycol 2000（DSPE-PEG-2000）, the water-soluble B-2TPA nanoparticles（NPs）had increasing1O2QY（6.7%） due to the intermolecular aggregation-induced decrease in the energy gap between singlet and triplet excited states. Moreover, the quenched fluorescence and stable twisted intramolecular charge transfer in aggregates further increased the PCE of B-2TPA NPs to 60.1%. In vitro and in vivo studies confirmed that B-2TPA NPs could be used in NIR fluorescence and photoacoustic imagingguided synergistic photodynamic and photothermal therapy in tumor treatment.

关键词： Aggregation Boron-dipyrromethene Intersystem crossing Photodynamic therapy Photothermal therapy Twisted intramolecular charge transfer