距离角度失配条件下的FDA-MIMO雷达运动目标检测算法

频控阵-多输入多输出(Frequency Diverse Array-Multiple Input Multiple Output,FDA-MIMO)雷达是一种新体制雷达,其发射频率分集特性带来了额外的距离维信息,然而采样误差同样带来了导向矢量失配的问题,不仅如此,角度误差的存在也会进一步加重导向矢量的失配,极大地影响检测器的检测性能。此外,目标速度过快也会对FDA-MIMO雷达的目标检测性能产生影响。速度带来的影响具体表现在两个方面:一方面会导致目标的距离走动,从而导致不同慢时间的回波包络不能对齐,无法相干积累;二是频率增量引起的多普勒扩展,使得不同发射通道的多普勒频率不一样,这会进一步影响检测性能。针对上述问题,本文针对运动目标情况下的目标检测问题进行研究,为了解决目标运动带来的距离徙动和多普勒扩展效应,引入Keystone变换进行校正。此外,为了提升阵列失配条件下的目标检测性能,本文引入子空间模型,提出了距离角度失配情况下的子空间构建方法,并基于广义似然比检验(Generalized Likelihood Ratio Test,GLRT)准则推导了FDA-MIMO雷达在距离和角度失配条件下的自适应检测器。仿真结果表明:在高斯白噪声背景下,所提算法可以校正运动目标在速度较快情况下导致的距离徙动和多普勒扩展效应,且在阵列距离和角度失配条件下的检测性能优于传统的GLRT检测器。此外本文所提Keystone-空域处理检测器与Keystone-全空时处理检测器的性能接近,且计算复杂度更低。

基于FDA不良事件报告系统数据库的别嘌醇和非布司他不良事件信号挖掘研究

目的基于FDA不良事件报告系统数据库对非布司他、别嘌醇进行不良事件信号挖掘,探索其潜在的用药风险,促进临床合理安全用药。方法提取FDA不良事件报告系统数据库2017年第一季度至2022年第二季度共22个季度有关非布司他、别嘌醇的不良事件报告数据,利用ROR法及PRR法对非布司他、别嘌醇不良事件(AE)进行信号挖掘。结果别嘌醇AE报告5060份,集中于≥60岁患者,累及系统器官分类项目(SOC)共计25项,主要累及在皮肤及皮下组织类疾病(40.01%),发现说明书中未累及系统12项,非布司他AE报告905份,累及SOC共计17项,主要累及在心脏器官疾病(40.17%),发现说明书中未累及系统2项。别嘌醇、非布司他累及感染及侵染类疾病(5.51%、0.49%),肝胆系统疾病(5.35%、0.87%),但别嘌醇说明书中均未收录。别嘌醇累及生殖系统及乳腺疾病(0.55%),妊娠期、产褥期及围产期状况(0.03%),但非布司他未发现累及以上SOC。结论别嘌醇较非布司他,说明书收录不良反应较不充分,新发现的累及SOC及AE为完善别嘌醇说明书不良反应可提供参考。研究发现别嘌醇和非布司他累及SOC差异,可为临床个体化治疗提供参考。

基于DQN和功率分配的FDA-MIMO雷达抗扫频干扰

频率分集阵列(Frequency Diversity Array,FDA)雷达由于其阵列元件的频率增量产生了许多新的特性,包括其可以通过发射功率分配进行灵活的发射波形频谱控制。在以扫频干扰为电磁干扰环境的假设下,首先,通过引入强化学习的框架,建立了频率分集阵列-多输入多输出(Frequency Diversity Array-Multiple Input Multiple Output,FDA-MIMO)雷达与电磁干扰环境交互模型,使得FDA-MIMO雷达能够在与电磁环境交互过程中,感知干扰抑制干扰。其次,本文提出了一种基于深度Q网络(Deep Q-Network,DQN)和FDA-MIMO雷达发射功率分配的扫频干扰抑制方法,使得雷达系统能够在充分利用频谱资源的情况下最大化SINR。最后,仿真结果证实,在强化学习框架下,FDA-MIMO雷达能够通过对发射功率分配进行优化,完成干扰抑制,提升雷达性能。

基于多普勒偏移补偿的非线性FDA-MIMO雷达运动目标检测算法

非线性频控阵-多输入多输出(Frequency Diverse Array-Multiple Input Multiple Output,FDA-MIMO)雷达具有非线性增加的阵元频偏,使得雷达的距离-角度波束图不再呈现“S”型,而聚焦为点波束,以此将发射能量聚焦到目标位置能够获得更优异的目标检测性能。不过,FDA-MIMO雷达检测运动目标时,由于发射阵元间的频偏与目标速度存在耦合,导致在慢时间维出现多普勒偏移。基于插值滤波的重采样算法能够补偿阵元频偏带来的多普勒偏移,但对于非线性FDA-MIMO雷达,由于阵元间频偏不再是线性变化,上述算法将会失效。本文提出了一种新的算法,可以利用Keystone变换和多普勒偏移补偿的方法,来检测非线性FDA-MIMO雷达中的运动目标。建立了非线性FDA-MIMO雷达运动目标的回波模型,指出了基于插值滤波的重采样算法存在的不足,提出了一种基于速度搜索的算法来补偿非线性FDA-MIMO雷达检测运动目标时出现的多普勒偏移。首先利用Keystone变换消除目标回波的距离徙动,然后根据阵元间频偏构造多普勒补偿函数,利用多普勒补偿函数和各阵元脉压后的回波信号构造速度搜索函数,通过设定合适的速度搜索范围对其进行搜索,当该函数取得峰值时对应的速度即为真实速度,最后利用搜索的速度补偿多普勒偏移后再做相干积累检测目标。仿真结果表明:所提算法可以准确补偿阵元间的多普勒偏移,且在非线性FDA-MIMO雷达体制下的检测性能优于基于插值滤波的重采样算法。

Low-Complexity Reconstruction of Covariance Matrix in Hybrid Uniform Circular Array

Spatial covariance matrix(SCM) is essential in many multi-antenna systems such as massive multiple-input multiple-output(MIMO). For multi-antenna systems operating at millimeter-wave bands, hybrid analog-digital structure has been widely adopted to reduce the cost of radio frequency chains.In this situation, signals received at the antennas are unavailable to the digital receiver, and as a consequence, traditional sample average approach cannot be used for SCM reconstruction in hybrid multi-antenna systems. To address this issue, beam sweeping algorithm(BSA) which can reconstruct the SCM effectively for a hybrid uniform linear array, has been proposed in our previous works. However, direct extension of BSA to a hybrid uniform circular array(UCA)will result in a huge computational burden. To this end, a low-complexity approach is proposed in this paper. By exploiting the symmetry features of SCM for the UCA, the number of unknowns can be reduced significantly and thus the complexity of reconstruction can be saved accordingly. Furthermore, an insightful analysis is also presented in this paper, showing that the reduction of the number of unknowns can also improve the accuracy of the reconstructed SCM. Simulation results are also shown to demonstrate the proposed approach.

基于GAMP算法的FDA-MIMO雷达的联合距离角度估计

MIMO雷达存在无法同时估计角度、距离的缺点,引入频率偏差带来距离维度信息(频控阵MIMO雷达),耦合了距离、角度信息,如何同时估计距离和角度成为提升系统能力的关键点。文章针对频控阵MIMO雷达系统中的角度、距离估计问题,提出了一种基于消息传递算法的近线性最小均匀误差估计算法。该算法根据角度分辨率和距离分辨率,将角度搜索空间和距离搜索空间划分为多个子区间,映射来波角度、距离门为稀疏向量。算法将角度估计、距离估计问题重构为稀疏线性模型,建立因子图,采用和积算法估计了该稀疏向量。同时,基于中心极限定理、大数定理近似和积算法中的消息,减少了计算复杂度。仿真结果表明,文章提出的算法可近似实现线性最小均匀误差估计,具有复杂度低、性能损失少、计算效率高等优点。

Chiral bound states in a staggered array of coupled resonators

We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent ones.In addition to the two typical bound states found above and below the energy bands,this system presents an extraordinary chiral bound state located within the energy gap.We use the chirality to quantify the breaking of the mirror symmetry.We find that the chirality value undergoes continuous changes by tuning the coupling strengths.The preferred direction of the chirality is controlled not only by the competition between the intracell and the intercell hoppings in the coupled-resonator array,but also by the coherence between the two coupling points.In the case with one coupling point,the chirality values varies monotonously with difference between the intracell hopping and the intercell hoppings.While in the case with two coupling points,due to the coherence between the two coupling points the perfect chiral states can be obtained.

Flexible capacitive pressure sensor based on interdigital electrodes with porous microneedle arrays for physiological signal monitoring

Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.

Age of Information for Short-Packet Covert Communication with Time Modulated Retrodirective Array

In this paper,the covert age of information(CAoI),which characterizes the timeliness and covertness performance of communication,is first investigated in the short-packet covert communication with time modulated retrodirective array(TMRDA).Specifically,the TMRDA is designed to maximize the antenna gain in the target direction while the side lobe is sufficiently suppressed.On this basis,the covertness constraint and CAoI are derived in closed form.To facilitate the covert transmission design,the transmit power and block-length are jointly optimized to minimize the CAoI,which demonstrates the trade-off between covertness and timelessness.Our results illustrate that there exists an optimal block-length that yields the minimum CAoI,and the presented optimization results can achieve enhanced performance compared with the fixed block-length case.Additionally,we observe that smaller beam pointing error at Bob leads to improvements in CAoI.

2D DOA Estimation of Coherent Signals with a Separated Linear Acoustic Vector-Sensor Array

In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spatial smoothing(PSS) technique is used to construct a block covariance matrix, so as to decorrelate the coherency of signals. Then a signal subspace can be obtained by singular value decomposition(SVD) of the covariance matrix. Using the signal subspace, two extended signal subspaces are constructed to compensate aperture loss caused by PSS.The elevation angles can be estimated by estimation of signal parameter via rotational invariance techniques(ESPRIT) algorithm. At last, the estimated elevation angles can be used to estimate automatically paired azimuth angles. Compared with some other ESPRIT algorithms, the proposed algorithm shows higher estimation accuracy, which can be proved through the simulation results.

New Antenna Array Beamforming Techniques Based on Hybrid Convolution/Genetic Algorithm for 5G and Beyond Communications

Side lobe level reduction(SLL)of antenna arrays significantly enhances the signal-to-interference ratio and improves the quality of service(QOS)in recent and future wireless communication systems starting from 5G up to 7G.Furthermore,it improves the array gain and directivity,increasing the detection range and angular resolution of radar systems.This study proposes two highly efficient SLL reduction techniques.These techniques are based on the hybridization between either the single convolution or the double convolution algorithms and the genetic algorithm(GA)to develop the Conv/GA andDConv/GA,respectively.The convolution process determines the element’s excitations while the GA optimizes the element spacing.For M elements linear antenna array(LAA),the convolution of the excitation coefficients vector by itself provides a new vector of excitations of length N=(2M−1).This new vector is divided into three different sets of excitations including the odd excitations,even excitations,and middle excitations of lengths M,M−1,andM,respectively.When the same element spacing as the original LAA is used,it is noticed that the odd and even excitations provide a much lower SLL than that of the LAA but with amuch wider half-power beamwidth(HPBW).While the middle excitations give the same HPBWas the original LAA with a relatively higher SLL.Tomitigate the increased HPBWof the odd and even excitations,the element spacing is optimized using the GA.Thereby,the synthesized arrays have the same HPBW as the original LAA with a two-fold reduction in the SLL.Furthermore,for extreme SLL reduction,the DConv/GA is introduced.In this technique,the same procedure of the aforementioned Conv/GA technique is performed on the resultant even and odd excitation vectors.It provides a relatively wider HPBWthan the original LAA with about quad-fold reduction in the SLL.

Microarrow sensor array with enhanced skin adhesion for transdermal continuous monitoring of glucose and reactive oxygen species

Conventional blood sampling for glucose detection is prone to cause pain and fails to continuously record glucose fluctuations in vivo.Continuous glucose monitoring based on implantable electrodes could induce pain and potential tissue inflammation,and the presence of reactive oxygen species(ROS)due to inflammationmay affect glucose detection.Microneedle technology is less invasive,yet microneedle adhesion with skin tissue is limited.In this work,we developed a microarrow sensor array(MASA),which provided enhanced skin surface adhesion and enabled simultaneous detection of glucose and H_(2)O_(2)(representative of ROS)in interstitial fluid in vivo.The microarrows fabricated via laser micromachining were modified with functional coating and integrated into a patch of a three-dimensional(3D)microneedle array.Due to the arrow tip mechanically interlocking with the tissue,the microarrow array could better adhere to the skin surface after penetration into skin.The MASA was demonstrated to provide continuous in vivo monitoring of glucose and H_(2)O_(2) concentrations,with the detection of H_(2)O_(2) providing a valuable reference for assessing the inflammation state.Finally,the MASA was integrated into a monitoring system using custom circuitry.This work provides a promising tool for the stable and reliable monitoring of blood glucose in diabetic patients.

Fixed-Time Sliding Mode Control With Varying Exponent Coefficient for Modular Reconfigurable Flight Arrays

The modular system can change its physical structure by self-assembly and self-disassembly between modules to dynamically adapt to task and environmental requirements. Recognizing the adaptive capability of modular systems, we introduce a modular reconfigurable flight array(MRFA) to pursue a multifunction aircraft fitting for diverse tasks and requirements,and investigate the attitude control and the control allocation problem by using the modular reconfigurable flight array as a platform. First, considering the variable and irregular topological configuration of the modular array, a center-of-mass-independent flight array dynamics model is proposed to allow control allocation under over-actuated situations. Secondly, in order to meet the stable, fast and accurate attitude tracking performance of the MRFA, a fixed-time convergent sliding mode controller with state-dependent variable exponent coefficients is proposed to ensure fast convergence rate both away from and near the system equilibrium point without encountering the singularity. It is shown that the controller also has fixed-time convergent characteristics even in the presence of external disturbances. Finally,simulation results are provided to demonstrate the effectiveness of the proposed modeling and control strategies.

Customization of FeNi alloy nanosheet arrays inserted with biomass-derived carbon templates for boosted electromagnetic wave absorption

Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband EMW-absorbing material remains an overwhelming challenge.Creating dielectric/magnetic composites with customized structures is a strategy with great promise for the development of high-performance EMW-absorbing materials.Using layered double hydroxides as the precursors of bimetallic alloys and combining them with porous biomass-derived carbon materials is a potential way for constructing multi-interface heterostructures as efficient EMW-absorbing materials because they have synergistic losses,low costs,abundant resources,and light weights.Here,FeNi alloy nanosheet array/Lycopodium spore-derived carbon(FeNi/LSC)was prepared through a simple hydrothermal and carbonization method.FeNi/LSC presents ideal EMW-absorbing performance by benefiting from the FeNi alloy nanosheet array,sponge-like structure,capability for impedance matching,and improved dielectric/magnetic losses.As expected,FeNi/LSC exhibited the minimum reflection loss of-58.3 dB at 1.5 mm with 20wt%filler content and a widely effective absorption bandwidth of 4.92 GHz.FeNi/LSC composites with effective EMW-absorbing performance provide new insights into the customization of biomass-derived composites as high-performance and lightweight broadband EMW-absorbing materials.

Design,preparation,application of advanced array structured materials and their action mechanism analyses for high performance lithium-sulfur batteries

Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.

美国FDA批准Zelsuvmi(Berdazimer)治疗传染性软疣

美国FDA于2024年1月5日批准新药Zelsuvmi(有效成分berdazimer,Berdazimer sodium的CAS登记号为308075-87-8)用于治疗传染性软疣(molluscum contagiosum)。据了解,Zelsuvmi剂型为外用凝胶(10.3%),研发商为Ligand药业公司(Ligand Pharmaceuticals),是FDA在2024年批准的第1种新药。

超声波手术机器人获FDA突破性设备认定

2024年3月4日,机器人超声治疗领域全球领导企业EDAPTMSSA(纳斯达克股票代码:EDAP)宣布,其FocalOne高强度聚焦超声(HIFU)平台已获得美国食品和药品监督管理局(FDA)的“突破性设备”认定,用于治疗深部浸润型子宫内膜异位症(DIE)。2018年6月,FDA已批准Focal One机器人用于前列腺组织消融。

美国FDA警示地舒单抗在晚期慢性肾病患者中严重低钙血症的风险增加

美国食品药品管理局(FDA)网站近期发布药品安全通讯,对骨质疏松药物地舒单抗(Denosumab,商品名:普罗力/Prolia)增加黑框警告,警示晚期慢性肾病患者用药后发生严重低钙血症的风险增加。

2023年美国FDA共批准55种新药

美国FDA下属的药品评审与研究中心在2023年共批准各类新药(包括新分子实体、新治疗用生物制品)55种,但不含由生物制品评审与研究中心负责评审的疫苗、致敏性产品、血液与血液制品、细胞与基因治疗产品:(1)有20种为同类首款(first-in-class)新药(商品名,下同):Daybue,Defencath,Fabhalta,Filspari,Filsuvez,Jesduvroq,Joenja,Lamzede,Miebo,Ogsiveo,Paxlovid,Qalsody,Rivfloza,Skyclarys,Sohonos,Talvey,Truqap,Veopoz,Veozah,Xdemvy。

基于FDA报告系统的乌司奴单抗严重不良事件分析与探讨

目的:运用美国食品药品监督管理局不良事件报告系统(FAERS)对乌司奴单抗上市后的不良事件进行数据挖掘和综合分析,为其临床安全用药提供参考依据。方法:利用报告比值比(ROR)法和比例报告比值比(PRR)法对FAERS数据库自2009年第4季度至2022年第1季度的乌司奴单抗相关不良事件进行数据挖掘及信号检测。结果:共得到乌司奴单抗相关药物警戒信号90个(116 311例次),同时满足ROR法及PRR法识别并排除同义合并、药物外不良事件,共得到38个药品不良信号(44 515例次),涉及12个系统器官分类,其中13个信号未在乌司奴单抗药品说明书中提及,涉及心脏器官疾病、胃肠系统疾病、各种肌肉骨骼及结缔组织疾病、全身性疾病及给药部位各种反应等;主要累积器官为全身性疾病及给药部位各种反应(9543例次)、肌肉骨骼及结缔组织疾病(9366例次)以及皮肤及皮下组织类疾病(5801例次)等;涉及死亡结局信号28个(811例次),按频次排序排名前二的分别为肺炎(95例次)和牛皮癣(60例次)。结论:应关注药品说明书中尚未涉及的严重的、新的药物警戒信号。用药治疗期间应密切关注给药部位、肌肉骨骼系统、皮肤系统及感染药物警戒信号,及早科学识别药品不良事件,做好相应防范,保障患者用药安全。