A Line Complex-Based Evolutionary Algorithm for Many-Objective Optimization

In solving many-objective optimization problems(MaO Ps),existing nondominated sorting-based multi-objective evolutionary algorithms suffer from the fast loss of selection pressure.Most candidate solutions become nondominated during the evolutionary process,thus leading to the failure of producing offspring toward Pareto-optimal front with diversity.Can we find a more effective way to select nondominated solutions and resolve this issue?To answer this critical question,this work proposes to evolve solutions through line complex rather than solution points in Euclidean space.First,Plücker coordinates are used to project solution points to line complex composed of position vectors and momentum ones.Besides position vectors of the solution points,momentum vectors are used to extend the comparability of nondominated solutions and enhance selection pressure.Then,a new distance function designed for high-dimensional space is proposed to replace Euclidean distance as a more effective distancebased estimator.Based on them,a novel many-objective evolutionary algorithm(MaOEA)is proposed by integrating a line complex-based environmental selection strategy into the NSGAⅢframework.The proposed algorithm is compared with the state of the art on widely used benchmark problems with up to 15 objectives.Experimental results demonstrate its superior competitiveness in solving MaOPs.

A Preliminary Study of Mapping Genes Underlying Complex Traits Based on Chromosome Segment Substitution Lines

Complex traits are the features whose properties are determined by multiple factors, which can be genetic or environmental. Most of economically important characteristics of plants and animals belong to this special catego-

A Characterization of Complex Projective Spaces by Sections of Line Bundles

Let M be a n-dimensional compact irreducible complex space with a line bundle L. It is shown that if M is completely intersected with respect to L and dimH0(M, L) = n + 1, then M is biholomorphic to a complex projective space Pn of dimension n.

3D reconstruction of complex curved objects from line drawings

An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve this problem, but they can＇t solve this problem when the geometric structure of a curved object becomes complex. This paper proposes a novel approach to reconstructing a complex curved 3D object from single 2D line drawings. Our approach has three steps： （1） decomposing a complex line drawing into several simpler line drawings and transforming them into polyhedron; （2） reconstructing the 3D wireframe of curved object from these simpler line drawings and generating the curved faces; （3） combining the 3D objects into the complete objects. A number of examples are given to demonstrate the ability of our approach to successfully perform reconstruction of curved objects which are more complex than previous methods.

考虑停运概率熵和网架结构熵的电网关键线路辨识方法

线路停运概率对连锁故障的触发和演化具有重要影响。然而,现有关于电网线路停运概率分布均衡性的研究存在考虑不足的问题。文中结合复杂网络理论分析方法与熵理论,提出综合考虑停运概率熵和网架结构熵的电网关键线路辨识方法,旨在量化线路在电网运行状态和网络状态层面的综合影响力。首先,基于线路停运概率模型,提出了停运概率分布熵与停运概率变化熵指标,区分了线路潮流在正常值范围内、正常值与极限值之间和大于极限值3个状态对辨识结果的影响,克服了现有指标中对直接影响线路故障因素考虑欠缺的不足。其次,结合改进网架结构熵,提出了反映电网网架结构和运行状态的关键线路综合指标。然后,结合功率平衡策略,提出电网关键线路辨识方法。最后,基于改进网络效能指标对IEEE 39节点系统和IEEE 118节点系统进行仿真,验证了所提方法的可行性和正确性。

A SCREW DISLOCATION IN A THREE-PHASE COMPOSITE CYLINDER MODEL WITH INTERFACIAL RIGID LINES

The problem of the elastic interaction between a screw dislocation and a three-phase circular inclusion with interracial rigid lines （anti-cracks） is investigated. An efficient and concise method for the complex multiply connected region is developed, with which explicit series form solutions of the complex potentials in the matrix, and the interphase layer and inclusion regions are derived. Based on the complex potentials, the image force on the screw dislocation is then calculated by using the Peach-Koehler formula. The equilibrium position of the dislocation is discussed in detail for various rigid line geometries, interphase layer thicknesses and material property combinations. The main results show that the interracial rigid lines exert a significant perturbation effect on the motion of the screw dislocation near the circular inclusion surrounded by an interphase layer.

Simulation of incompressible multiphase flows with complex geometry using etching multiblock method

The incompressible two-phase flows are simulated using combination of an etching multiblock method and a diffuse interface （DI） model, particularly in the com- plex domain that can be decomposed into multiple rectangular subdomains. The etching multiblock method allows natural communications between the connected subdomains and the efficient parallel computation. The DI model can consider two-phase flows with a large density ratio, and simulate the flows with the moving contact line （MCL） when a geometric formulation of the MCL model is included. Therefore, combination of the etch- ing method and the DI model has potential to deal with a variety of two-phase flows in industrial applications. The performance is examined through a series of numerical exper- iments. The convergence of the etching method is firstly tested by simulating single-phase flows past a square cylinder, and the method for the multiphase flow simulation is vali- dated by investing drops dripping from a pore. The numerical results are compared with either those from other researchers or experimental data. Good agreement is achieved. The method is also used to investigate the impact of a droplet on a grooved substrate and droplet generation in flow focusing devices.

Modifying factor for determining broadband complex permeability of magnetic thin films

A new method of the modifying factor for determining the broadband complex permeability of magnetic thin films,was proposed. Based on the measurement technology of shot-end microstrip line and the new modify factor,a series of FeCo-based magnetic thin films deposited on the oxidized silicon substrates and with an in-plane uniaxial anisotropy were measured in the frequency range of 0.5-5 GHz. The results fit well with the Landau-Lifchitz-Gilbert theory in a broad frequency range.

Analysis of a piezoelectric screw dislocation inside an elliptical inhomogeneity with confocal rigid line in piezoelectric material

This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under remote anti-plane shear stresses and in-plane electrical loads in piezoelectric composite material. The analytical-functions of the complex potentials, stress fields and the image force acting on the piezoelectric screw dislocation are obtained based on the principle of conformal mapping, the method of series expansion, the technical of analytic continuation and the analysis of singularity of complex potentials. The rigid line and the piezoelectric material property combinations upon the image force and the equilibrium position of the dislocation are discussed in detail by the numerical computation.

ANTIPLANE PROBLEM OF CIRCULAR ARC INTERFACIAL RIGID LINE INCLUSIONS

The antiplane problem of circular arc rigid line inclusions under antiplane concentrated force and longitudinal shear loading was dealt with. By using Riemann-Schwarz's symmetry principle integrated with the singularity analysis of complex functions, the general solution of the problem and the closed form solutions for some important practical problems were presented. The stress distribution in the immediate vicinity of circular arc rigid line end was examined in detail. The results show that the singular stress fields near the rigid inclusion tip possess a square-root singularity similar to that for the corresponding crack problem under antiplane shear loading, but no oscillatory character. Furthermore, the stresses are found to depend on geometrical dimension, loading conditions and materials parameters. Some practical results concluded are in agreement with the previous solutions.

PLANE ELASTIC PROBLEM ON RIGID LINES ALONG CIRCULAR INCLUSION

The plane elastic problem of circular-arc rigid line inclusions is considered. The model is subjected to remote general loads and concentrated force which is applied at an arbitrary point inside either the matrix or the circular inclusion. Based on complex variable method, the general solutions of the problem were derived. The closed form expressions of the sectionally holomorphic complex potentials and the stress fields were derived for the case of the interface with a single rigid line. The exact expressions of the singular stress fields at the rigid line tips were calculated which show that they possess a pronounced oscillatory character similar to that for the corresponding crack problem under plane loads. The influence of the rigid line geometry, loading conditions and material mismatch on the stress singularity coefficients is evaluated and discussed for the case of remote uniform load.

端接复杂电路传输线网络的电磁耦合时域并行计算方法

针对端接复杂电路传输线(TL)网络的电磁耦合问题,仍缺乏高效的场路协同仿真技术。该文将传输线方程与时域有限差分(FDTD)方法、诺顿定理和置换定理以及NGSPICE软件相结合,并引入消息传递接口(MPI)并行技术,提出一种高效的时域混合并行算法(FDTDTL-NGSPICE)。首先,根据诺顿定理和置换定理,将传输线网络分解为传输线子系统和复杂电路子系统,并构建对应的等效电路模型。然后,使用FDTDTL并行算法计算传输线子系统沿线各点的电压和电流,并获取对应诺顿等效电路的电流源和等效导纳大小。最后,使用NGSPICE对复杂电路子系统进行传导干扰分析,获得复杂电路各元件上的瞬态响应,并将端口电压反馈给传输线子系统作为边界,实现传输线网络电磁耦合的场线路联合协同仿真。通过对3类典型场景的计算实例,分别使用时域混合并行算法和电磁仿真软件CST电缆工作室(CS)进行数值模拟并对比,验证所提算法的置信度。

基于拓扑分形方法的裂缝网络体系

川南地区经历了多期多阶段的构造变形事件,形成了多期构造复合-联合的叠加构造变形带,并伴生着较为发育的裂缝网络体系。为了定量化表征永川地区的构造变形强度,通过提取永川地区裂缝数据,基于拓扑结构分析的方法,运用了裂缝线密度、裂缝连通率两项拓扑指标对永川地区的构造变形强度进行了量化。并对量化评价结果与页岩气井产量进行相关性分析,相关性分析结果显示裂缝线密度的数值在0~0.986×10^(-3)的区间范围内,裂缝线密度与页岩气井产量强正相关,即裂缝网络体系越发育,页岩气产量越高,超过0.986×10^(-3)并在0.986×10^(-3)~1.342×10^(-3)区间内某一点开始,过于发育的裂缝网络体系反而致使页岩气产量降低。而裂缝连通率数值与页岩气井产量呈弱的负相关,即裂缝连通率数值越高,页岩气产量越低。

复杂环境下基于自适应极线约束的AGV视觉SLAM算法

针对传统视觉同步定位与地图构建(SLAM)算法不能有效处理复杂环境中的动态及潜在动态目标而影响定位与建图性能的问题,提出一种基于Mask R-CNN神经网络以及ORB-SLAM3算法改进的视觉SLAM方法。针对动态目标,提出一种基于语义信息的运动一致性检验算法,使用自适应阈值的极线约束方法实现图像中动态特征点的精确剔除;针对潜在动态目标,提出一种改进的长期数据关联方法,通过增大关键帧选取密度及优化关键帧中的潜在动态目标信息,对算法的回环优化和地图融合过程进行改进,提高回环优化效果与地图复用性。在TUM数据集和真实场景中进行验证,实验结果表明与ORB-SLAM3算法相比,采用TUM数据集在低动态场景和高动态场景中的绝对轨迹均方根误差分别减小8.5%和65.6%;在真实场景下测试,所提算法的定位精度提高了62.5%。

烟草生物碱性状的QTL定位

生物碱是烟草的重要化学成分。为明确烟草生物碱的遗传结构,发掘控制相关性状的主效位点,以烟草品种Y3、K326为亲本,构建大小为271的重组自交系群体。分别于2018、2019和2020年在云南省昆明市石林、玉溪市研和种植群体材料,检测总植物碱(TPA)、烟碱(NIC)、降烟碱(NOR)、假木贼碱(ANAB)和新烟草碱(ANAT)5种生物碱表型。对群体进行基因组测序,构建包含46,129个标记的遗传连锁图谱。利用基于混合线性模型的QTL定位方法及软件QTLNetwork2.0,进行QTL定位分析。共定位15个具有显著加性效应的QTL,加性效应对表型贡献率为0.58%~11.57%。其中4个主效QTL即控制总植物碱的qTPA14、烟碱的qNIC14、假木贼碱的qANAB14和新烟草碱的qANAT14,均可以解释相应性状10%以上的表型变异,且均位于14号连锁群上。6个QTL具有显著的加性与环境互作效应,对表型贡献率为0.80%~1.81%。5对QTL具有显著加性-加性上位性效应,对表型的贡献率为0.15%~2.31%。2对QTL具有显著的上位性与环境互作效应,对表型的贡献率为0.81%~1.16%。研究结果为进一步分离候选基因、解析遗传机理和促进烟草生物碱性状分子改良奠定了基础。

基于空间句法的中小型街区式商业综合体动线空间设计的研究

中小型街区式商业综合体是当代社会发展下的一种新的商业模式,该商业形态丰富、空间功能复合,注重消费者的空间体验和心理需要,一个成功的街区式商业体,离不开好的动线空间设计。该文基于空间句法理论,以两个同类型的商业体的动线空间为代表案例,通过构建空间句法模型进行分析,总结出可取的设计策略并应用,以期对该类型商业动线空间的设计提供借鉴。

基于新型编码解码网络的复杂输电线识别

构建新型编码解码网络实现图像中多根交叉复杂输电线的高精度快速识别.为了减少网络参数,编码器取常规MobileNetV3的前16层,并且采用坐标注意力机制代替常规MobileNetV3的挤压和激励注意力机制,获取特征图的通道信息和位置信息;解码器通过金字塔池化模块获取输电线多尺度特征信息,提高识别精度;采用跳跃链接将编码器第2、4、7、11和13层特征图经锐化核卷积处理后分别与解码器的特征图堆叠,加强复杂输电线边缘特征提取;引入混合损失函数解决图像中输电线像素少、背景像素多的类别不平衡问题;利用迁移学习加快网络训练速度.实验结果表明,新型编码解码网络的平均像素精度(MPA)、平均交并比(MIOU)和识别速度分别为92.18%、84.27%和32帧/s,优于PSPNet、U2Net和其他输电线识别网络的.

复杂背景下的结构光条纹中心提取算法研究

线结构光三维扫描建模系统中最关键的一步是提取光条中心线,但环境中各种因素的干扰给中心线提取带来困难。针对线结构光条纹图像存在光斑干扰、光强分布不均、光条宽度差别大、背景复杂等多种问题,提出解决方案。首先采用Otsu对结构光图像二值化;其次采用改进DBSCAN(density-based spatial clustering of applications with noise)算法保留核心点,去除边界点和噪声点;最后将核心点作为输入,构建图数据结构,采用适用于线结构光条纹图像的最短路径搜索算法得到光条中心线。实验结果表明,该算法运行时间在150 ms以内,误差在0.2像素以内,并适用于多种复杂环境,满足实时性、准确性和稳定性的要求。

基于耦合线和复阻抗拓扑的宽带功分电路设计

提出了一种基于耦合线和复阻抗的宽带功分电路拓扑,通过将功分支路设计成耦合传输线和在隔离网络中引入耦合线传输线和单端传输线组合的复隔离阻抗,设计并实现了一款宽带、高隔离功分电路。此外,对所提出的功分电路拓扑采用奇偶模理论进行建模和分析,给出了关键参数的优化过程。在此基础上,基于带状线实现了所提功分电路的拓扑,并在输入输出接口位置集成了带状线至微带线的过渡转换结构,用于实现功分电路与其他电路器件的互连及实际性能测试。最后,对功分单元和一分四功分网络进行了加工和测试,测试结果表明所设计的功分单元在8~16 GHz宽频段范围内回波损耗大于10 dB,插入损耗小于2.2 dB,输出端口间隔离大于19 dB;一分四功分网络在该频段内的回波损耗大于9.5 dB,插入损耗小于3.7 dB,输出端口间隔离在15 dB左右。