Combat situation suppression of multiple UAVs based on spatiotemporal cooperative path planning

Aiming at the suppression of enemy air defense(SEAD)task under the complex and complicated combat sce-nario,the spatiotemporal cooperative path planning methods are studied in this paper.The major research contents include opti-mal path points generation,path smoothing and cooperative rendezvous.In the path points generation part,the path points availability testing algorithm and the path segments availability testing algorithm are designed,on this foundation,the swarm intelligence-based path point generation algorithm is utilized to generate the optimal path.In the path smoothing part,taking ter-minal attack angle constraint and maneuverability constraint into consideration,the Dubins curve is introduced to smooth the path segments.In cooperative rendezvous part,we take esti-mated time of arrival requirement constraint and flight speed range constraint into consideration,the speed control strategy and flight path control strategy are introduced,further,the decoupling scheme of the circling maneuver and detouring maneuver is designed,in this case,the maneuver ways,maneu-ver point,maneuver times,maneuver path and flight speed are determined.Finally,the simulation experiments are conducted and the acquired results reveal that the time-space cooperation of multiple unmanned aeriel vehicles(UAVs)is effectively real-ized,in this way,the combat situation suppression against the enemy can be realized in SEAD scenarios.

Interpolation of near offset using surface-related multiples

In this research, we present a seismic trace interpolation method which uses seismic data with surface-related multiples. It is different from conventional seismic data interpolation using information transformation or extrapolation of adjacent channels for reconstruction of missing seismic data. In this method there are two steps, first, we construct pseudo-primaries by cross-correlation of surface multiple data to extract the missing near- offset information in multiples, which are not displayed in the acquired seismic record. Second, we correct the pseudo-primaries by applying a Least-squares Matching Filter （LMF） and RMS amplitude correction method in time and space sliding windows. Then the corrected pseudo-primaries can be used to fill the data gaps. The method is easy to implement, without the need to separate multiples and primaries. It extracts the seismic information contained by multiples for filling missing traces. The method is suitable for seismic data with surfacerelated multiples.

Multiple interferences suppression with space-polarization null-decoupling for polarimetric array

The adaptive digital beamforming technique in the space-polarization domain suppresses the interference with forming the coupling nulls of space and polarization domain.When there is the interference in mainlobe,it will cause serious mainlobe distortion,that the target detection suffers from.To overcome this problem and make radar cope with the complex multiple interferences scenarios,we propose a multiple mainlobe and/or sidelobe interferences suppression method for dual polarization array radar.Specifically,the proposed method consists of a signal preprocessing based on the proposed angle estimation with degree of polarization(DoP),and a filtering criterion based on the proposed linear constraint.The signal preprocessing provides the accurate estimated parameters of the interference,which contributes to the criterion for null-decoupling in the space-polarization domain of mainlobe.The proposed method can reduce the mainlobe distortion in the space-polarization domain while suppressing the multiple mainlobe and/or sidelobe interferences.The effectiveness of the proposed method is verified by simulations.

Multiple Suppression Using T-A Dual Polynomial Fitting Method

Principles of polynomial fitting zero offset profile are introduced, and a new polynomial fitting method, tbe time-amplitude dual fitting method, is developed. The method can be used to purify seismic waves and suppress multiples. The effect of suppressing multiples is compared with other multiple suppression methods.

Surface-Related Multiple Elimination on High-Resolution Geopulse Profile

A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water （ 〈 25 m）, free surface-related multiples are conflicted with the flat primaries, which may instruct the interpreters in a wrong way and make wrong conclusions. Owing to the variation of multiple periods, standard anti-multiple techniques may lose their power, such as predictive deconvolution. Surface-related multiple elimination methods are introduced to attenuate the multiples based on the underlying waveequation principles. The results justified the method on the single-channel geopulse profile, revealing the real nature of the subsurface.

Effects of Bortezomib and Dexamethasone combination on treating senile multiple myeloma and influence on immune suppressed factors and immune cell levels

Objective:To investigate the effects of Bortezomib and Dexamethasone combination on treating senile multiple myeloma and influence on immune suppressed factors and immune cell levels.Methods:A total of 80 cases of patients with multiple myeloma treated in our hospital from Oct 2013 to Jul 2015 were selected as investigate subjects. They were randomly divided to be observation group consisted of 43 cases and control group consisted of 37 cases. For observation group, treatment of Bortezomib and Dexamethasone combination was provided. For control group, Vincristine + Epirubicin + Dexamethasone treatment was provided. After three courses, effects on two groups of patients were compared, and immune suppressed factors and immune cell levels before and after treatment in different periods were compared.Results:After three courses of treatment, the total effective rate in observation group was significantly higher than control group. Before treatment, IL-6, IL-17, TGF-β, CD3+CD4+, CD3+CD8+ and CD3+CD4+/CD3+CD8+ between the two group of patients were compared, no significant difference showed;After treatment for 6 weeks, IL-6, IL-17 levels in observation group were significantly decreased comparing with the same group before treatment;After treatment for 12 weeks, IL-6, IL-17 and TGF-β levels in observation group were significantly decreased comparing with the same group before treatment;After treatment, IL-6, IL-17 levels in observation group were significantly lower than control group at the same phase. After treatment for 12 weeks, CD3+CD4+, CD3+CD4+/CD3+CD8+ in observation group were significantly higher than the same group before treatment, and significantly higher than control group at the same phase;CD3+CD8+ in observation group was significantly lower than the same group before treatment, and significantly lower than control group at the same phase. Conclusion:Compared with Vincristine + Epirubicin + Dexamethasone treatment, Bortezomib and Dexamethasone combination on treating senile multiple myeloma had more significant effects, which deserves further clinical researches.

Combined Adaptive Multiple Subtraction Based on Optimized Event Tracing and Extended Wiener Filtering

The surface-related multiple elimination(SRME) method is based on feedback formulation and has become one of the most preferred multiple suppression methods used. However, some differences are apparent between the predicted multiples and those in the source seismic records, which may result in conventional adaptive multiple subtraction methods being barely able to effectively suppress multiples in actual production. This paper introduces a combined adaptive multiple attenuation method based on the optimized event tracing technique and extended Wiener filtering. The method firstly uses multiple records predicted by SRME to generate a multiple velocity spectrum, then separates the original record to an approximate primary record and an approximate multiple record by applying the optimized event tracing method and short-time window FK filtering method. After applying the extended Wiener filtering method, residual multiples in the approximate primary record can then be eliminated and the damaged primary can be restored from the approximate multiple record. This method combines the advantages of multiple elimination based on the optimized event tracing method and the extended Wiener filtering technique. It is an ideal method for suppressing typical hyperbolic and other types of multiples, with the advantage of minimizing damage of the primary. Synthetic and field data tests show that this method produces better multiple elimination results than the traditional multi-channel Wiener filter method and is more suitable for multiple elimination in complicated geological areas.

First-order multiples imaging aided by water bottom

Surface-related multiples frequently propagate into the subsurface and contain abundant information on small reflection angles.Compared with the conventional migration of primaries,migration of multiples offers complementary illumination and a higher vertical resolution.However,crosstalk artifacts caused by unrelated multiples during reverse time migration(RTM)using multiples severely degrade the reliability and interpretation of the final migration images.Therefore,we proposed RTM using first-order receiver-side water-bottom-related multiples for eliminating crosstalk artifacts and enhancing vertical resolution.We first backward propagate the first-order receiver-side water-bottom-related multiples using a water-layer model,followed by saving the upper boundary wavefield.Then we produce the source wavefield using a seismic wavelet and the receiver wavefield by back-extrapolating the saved boundary.Finally,the cross-correlation imaging condition is applied to generate the final image.This method transforms the receiver-side multiples into primaries,followed by the conventional migration processing procedures.Numerical examples using synthetic datasets demonstrate that our method significantly enhances the imaging quality by eliminating crosstalk artifacts and improving the resolution.

ANALYSIS OF TRANSMIT BEAMFORMING PERFORMANCE ON MULTIPLE-TRANSMIT BINARY ZCZ WAVEFORMS

The Transmit BeamForming (TBF) technology, applied in a multiple-transmit radar system, is studied in this paper, where multiple elements of antenna array transmit binary Zero Correlation Zones Orthogonal Signals (ZCZ-OS) independently. For each Direction Of Arrival (DOA) with respect to the transmitting array, the analysis on the gain and sidelobe level of TBF output is presented. This paper focuses on the range sidelobes performance within the main beam (in angle domain). For the normal direction, due to the inherent phase property of ZCZ-OS, the TBF output has part zero sidelobes area, of which the distribution is discussed. For the other directions, a systematic search algorithm to optimize the transmission order of signals is proposed for an optimal relationship chart of DOA and transmission order. The range sidelobe performance within the main beam can be improved as the optimal transmission order is adopted.

Dynamic Behavior and Vibration Suppression of a Generally Restrained Pre-pressure Beam Structure Attached with Multiple Nonlinear Energy Sinks

Beam structures are extensively used in many engineering branches.For marine engineering,the ship shafting system is generally simplified as a vibration model with single or multiple beam structures connected by the coupling stiffness.In engineering,multiple nonlinear energy sinks(NESs)can be arranged on the premise of sufficient installation space to ensure their vibration suppression effect.Considering engineering practice,this study investigates the dynamic behavior and vibration suppression of a generally restrained pre-pressure beam structure with multiple uniformly distributed NESs,where the prepressure is typically caused by thrust bearings,installation ways,and others.System governing equations are derived through the generalized Hamiltonian principle and the variational procedure.Dynamic responses of the pre-pressure beam structure are predicted by the Galerkin truncation method.The effect of NESs on dynamic responses and vibration suppression of the pre-pressure beam structure is studied and discussed.Suitable parameters of NESs have a beneficial effect on the vibration suppression at both ends of the pre-pressure beam structure.NESs can modify the vibration frequency and energy transmission characteristics of the vibration system.For different boundary conditions,the optimized parameters of NESs significantly suppress the vibration energy of the pre-pressure beam structure.

单脉冲测角的二维分级主旁瓣干扰联合抑制方法

针对矩形平面阵列天线同时存在主、旁瓣干扰的单脉冲测角问题,该文设计了2维分级自适应单脉冲波束形成算法(TDHJ-ADBF)。TDHJ-ADBF算法将矩形平面阵分为方位维和俯仰维两个正交维度,采用2维分级处理架构:第1级处理在测角维进行,采用低运算量的压缩多重信号分类法对测角维主瓣干扰进行快速识别与方向估计,构造阻塞矩阵滤除主瓣干扰,获得仅含旁瓣干扰和噪声的协方差矩阵,进而对和、差波束方向图进行指向与鉴角曲线联合约束,完成测角维旁瓣干扰抑制与波束形成处理;第2级在非测角维对残留的测角维主瓣干扰进行抑制。通过2维分级处理实现主、旁瓣干扰联合对抗,并保持单脉冲测角的鉴角曲线线性度。仿真结果表明,TDHJ-ADBF算法实现了对主、旁瓣干扰联合抑制,具有高精度的单脉冲测角性能。

OBN地震数据成像处理基本逻辑与关键方法技术

海洋油气勘探逐渐进入深水深层勘探领域,地下地质构造复杂(横向变速剧烈)、目标油藏复杂(由以构造油气藏为主转向构造与地层岩性油气藏并重),同时还可能伴随海底地形及附近岩性的复杂变化,所有因素促使海洋油气地震勘探技术不断变革。提高海洋油气勘探效益的首要问题是发展尽可能满足高精度地震波成像需求的地震数据采集技术及对应的高精度地震波成像技术。当前,无论海上和陆上油气地震勘探,“两宽一高”地震数据采集技术和全波形反演(FWI)/最小二乘逆时偏移(LS_RTM)为代表的地震波成像技术是标志性的领先技术。海上油气地震勘探中,海底节点(OBN)地震数据采集是目前业界公认的、最有可能真正实现“两宽一高”地震数据采集的技术。与拖缆数据采集相比,OBN数据采集具有宽方位照明、数据信噪比高、无检端鬼波、存在实测的(至少一阶自由表面相关)下行波场、四分量观测等优点。尤其是宽方位照明和存在至少一阶自由表面下行波场的特点,使得OBN数据具备了对中深层复杂构造和近海底介质进行高精度成像的能力。着重讨论了高精度地震波成像对地震数据采集的要求,指出OBN数据采集在海洋油气勘探中的必要性;分析了OBN数据采集的地震波场的特点,据此提出OBN数据地震波成像处理的基本逻辑及相应的关键技术;认为海洋油气勘探中地震波成像处理的特殊问题主要由特征反射层引起,海水面、海底面和地下介质中若干强反射层构成了这些特征反射层,提出了模型驱动波动理论特征反射层相关多次波预测与压制的技术路线,并对比了几种代表性的多次波预测的基础理论;指出对应当前的线性化偏移成像算子叠前数据域与叠前成像域是等价的,据此以成像道集后处理为中心,给出期望成像道集的定义,将弱旁瓣、定量的反射系数作为保真高分辨地震波成像的目标,在两个域中尽可能完美实现地下同一反(绕/散)射点、不同炮检距反(绕/散)射子波的同相位叠加,尽可能好地实现保真高分辨带限反射系数的成像;提出最好把带限反射系数成像推进到宽带波阻抗成像的技术路线;结合OBN数据的特点,给出了OBN数据地震波成像处理的基本技术流程,指出各环节的关键方法技术。最后,针对OBN数据四分量观测的特点,指出是实际观测的多波地震波场中的波现象(主要是P_SV波)与地震波传播及模拟理论不匹配导致了当前多波成像结果达不到预期,建议重点研究实际观测的多波地震波场中的波现象与地震波传播及模拟理论不匹配的物理根源,而不是发展更高端的矢量波成像算法。期望本文的思想观点对OBN地震勘探在海洋油气勘探中的进一步应用产生积极的促进作用。

射线追踪驱动的三维斜缆地震资料海底多次波预测

斜缆采集已成为海上宽频地震采集中常用的采集方式,本文针对斜缆地震数据的多次波预测问题,提出了射线追踪驱动的三维斜缆地震资料海底多次波预测方法。首先基于叠加速度(或偏移速度)的射线追踪方法,根据炮点深度、检波点深度模拟出海底多次波的大体时间延迟量,并基于原始数据的相关谱分析确定出与海底多次波周期拟合最佳的延迟时,然后通过时空域(偏移距域)的褶积过程实现海底多次波预测。模型数据试验和对实际数据的处理试验结果均证实了本文提出的方法能够有效地预测斜缆地震资料海底多次波,其在实际斜缆地震数据的多次波压制处理中具有广阔的应用前景。

High Permeability in Broadband of Co-sputtered [Fe-Fe_(20)Ni_(80)/Cr]_(n) Multilayer Films

To achieve high microwave permeability in wide-band for the micron-thick magnetic films,[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer structure was proposed by co-sputtering Fe and FeNi to form the magnetic layers and Cr to form the interlayers.The multilayer structure contributes to the high permeability by reducing the coercivity and diminishing out-of-plane magnetization.The maximum imaginary permeability of[Fe-Fe_(20)Ni_(80)/Cr]_(n) multilayer film reaches a large value of 800 at 0.52 GHz even though its overall thickness exceeds 1μm.Besides,the magnetic resonance frequency of the multilayer film can be modulated from 0.52 to 1.35 GHz by adjusting the sputtering power of Fe from 0 to 86 W,and its bandwidth for μ’’>200(Δf) is as large as 2.0 GHz.The desirable broad Δf of magnetic permeability,which can be well fitted by the Landau-Lifshitz-Gilbert equations,is due to dual magnetic resonances originated from double magnetic phases of Fe and FeNi that are of different saturation magnetization.The micron-thick multilayer films with high permeability in extended waveband are promising candidate for electromagnetic noise suppression application.

曲率放大的λ-f域高分辨率抛物Radon变换多次波压制方法

在实际数据处理中抛物Radon变换是多次波压制的一种常用手段,然而,常规Radon变换方法难以有效压制那些与一次波曲率差异较小的多次波,本文给出了曲率放大的多次波压制方法来改善多次波的压制效果。通过研究影响同相轴的曲率的参数,发现压缩炮检距或增大时差能够放大多次波和一次波曲率差异,加大一次波和多次波在Radon域的分离程度,从而提高了多次波的压制能力。为进一步提高Radon变换的计算效率和精度,采用λ-f域高分辨率抛物Radon变换,通过引入新变量λ消除了常规Radon变换算子对频率的依赖性,由于变换算子和它的逆只需要计算一次,因此显著提高了计算效率。通过理论模型和实际资料的处理表明,该方法能够较好地压制表层多次波,对于那些与一次波存在一定曲率差异的层间多次波,也具备一定的压制能力。

基于L_(1/2)正则化的抛物线Radon变换多次波压制方法

在地震数据处理中,多次波的存在会对地震数据成像和地震资料解释带来影响,如何有效地压制多次波干扰是地震勘探中的重要问题。抛物线Radon变换因其高效的特点被广泛应用于多次波压制中,但在野外地震数据采集时,炮检距的有限性会导致变换域中的能量扩散,产生假象,使多次波压制达不到理想的效果。针对此问题,提出一种基于L_(1/2)正则化的稀疏反演高分辨抛物线Radon变换,并应用广义迭代收缩算法(generalized iterated shrinkage algorithm,GISA)进行求解。研究结果表明,L_(1/2)正则化有很强的稀疏约束能力,能提高解的稀疏度,改进信噪分离的效果。与最小二乘反演和基于L_(1)正则化的稀疏反演相比,基于L_(1/2)正则化的稀疏反演高分辨抛物线Radon变换能更有效地压制多次波,并确保了重构数据与原始数据的一致性。

基于深度残差傅里叶神经算子方法压制地震多次波

多次波是一种较为严重影响地震成像的干扰波,如何有效压制多次波是需要关注的地震资料处理关键问题之一.本文基于傅里叶神经算子(FNO)和残差网络(ResNet),提出了基于深度残差傅里叶神经算子(DRFNO)网络的多次波压制方法.DRFNO是一种弱约束模型+数据驱动的人工智能算法,包含一次波和多次波的全波场炮集为输入,其中真实一次波炮集为标签训练网络,输出为压制多次波后的一次波炮集.DRFNO的网络结构中考虑了地震波场的数据特点,结合波动方程正演模拟的物理机理,约束网络训练过程.基于传统机器学习中的激活函数设置方法,该方法通过一个用于地震数据样本与标签预处理的激活函数(SDAF),克服地震炮集数据中因同相轴能量差异导致神经网络无法训练的问题.采用两套层状介质模型和Sigsbee2B复杂模型的模拟地震数据验证了DRFNO方法多次波压制处理的有效性,抗噪性和泛化能力.最后,通过一套实际地震数据实例表明本文提出的DRFNO方法应用于压制实际复杂地震波场中多次波的良好效果.

多源宽带干扰对消建模及干扰抑制需求分析

为解决宽带干扰对消中的多源干扰抑制问题,建立多源宽带干扰对消的理论模型,得到了取样天线和时域滤波器数量对干扰抑制性能的影响规律。分析干扰源间相关性对干扰抑制性能的影响,研究多干扰源和单干扰源干扰对消比的差异性,提出压缩系数作为衡量多干扰源干扰对消比的指标,并得到了多源宽带干扰对消的干扰抑制需求。实验结果表明,增大取样天线和时域滤波器数量可以显著提高双干扰源的干扰对消比。在相同场景下,双干扰源的干扰对消比低于单干扰源10 dB以上,而且随着双干扰源的功率差变大,压缩系数降低,干扰对消比逐渐降低。当二者的功率差超过25 dB后,压缩系数接近于1,双干扰源等效为单干扰源。

基于无监督神经网络匹配算法的叠前表面多次波压制方法

为了有效地压制海上地震勘探数据中的表面多次波,实现勘探目标的正确成像,提出一种基于无监督神经网络的叠前表面多次波匹配算法,将神经网络方法与表面相关多次波压制方法相结合,通过设定学习率不断下降,用无监督神经网络取代匹配滤波算子,对叠前地震数据进行表面多次波的压制,既不需要传统的匹配算法,也不需要在标签数据集上进行训练。在简单合成数据、Sigsbee模型数据和实际数据上的应用结果验证了该方法对表面多次波压制的有效性。

双边供电下的钢轨电位影响因素及抑制措施分析

双边供电方式能够实现长距离无分相贯通供电,与单边供电方式相比系统牵引回流特性有差异,进而将导致钢轨电位分布不同,故需对双边供电方式下的钢轨电位进行研究。基于双边供电复线牵引网模型,推导了系统钢轨电位及轨中电流计算过程,通过分析钢轨电位的影响因素提出双边供电复线牵引网钢轨电位的抑制措施。研究结果表明:单边供电与双边供电取流点附近的钢轨电位基本一致,但双边供电方式下会在牵引变电所处造成更低的钢轨电位。双边供电方式下,钢轨电位在机车取流处达到最大值,取流点两侧钢轨电位逐渐减小,当上下行机车位置关于相邻变电所区间中点对称时,该区间内钢轨电位分布几乎一致,机车越靠近相邻变电所区间中点钢轨电位越大,列车运行组织应尽量避免机车在靠近两相邻变电所区间中点会车。轨地过渡电阻3Ω·km增大到15Ω·km时,钢轨电位最大值从52.49 V增大到109.01 V,增幅为107.68%,可通过降阻达到钢轨电位抑制效果。土壤电阻率从10Ω·m增加到200Ω·m时,牵引变电所处的钢轨电位从10.82 V增加到36.74 V,增幅为239.56%。钢轨电位分析与治理需充分考虑线路周围土壤条件。增设贯通地线后,机车取流处钢轨电位迅速降低,抑制钢轨电位效果显著。