基于有向邻接矩阵的配电网拓扑检测与识别

准确的拓扑结构是配电网精细化管理和安全运行的基础。针对现有配电网拓扑识别方法无法确定网络潮流方向以及拓扑变动检测方法受负荷突变影响大的问题,提出一种基于有向邻接矩阵的配电网拓扑变动检测与识别方法。首先,提出一种基于有向邻接矩阵的配电网拓扑识别模型,将配电网的未知拓扑描述为不确定的有向邻接矩阵,实现配电网的拓扑识别并确定潮流方向。其次,提出一种基于节点电压邻接矩阵的拓扑变动检测方法,通过分析相邻节点电压幅值的下降趋势判断拓扑是否发生变动。此外,所提出的拓扑变动检测方法可以缩小未知拓扑的范围,降低拓扑识别问题的变量规模。最后,通过仿真分析验证了所提方法的正确性和有效性。

防火墙干扰下网络拓扑检测技术的研究

Internet上面部署的各种各样的防火墙给网络拓扑检测工作带来了很大的困难。通过对防火墙的安全规则进行分析,本文提出了多协议活节点探测方法和多协议网络路径检测方法,从而形成了一套系统的针对防火墙干扰的网络拓扑检测方法。

基于CPCI总线TS201模块板拓扑检测功能实现

简要介绍了TS201的特点,描述基于CPCI总线TS201模块板拓扑测试软件的功能和实现原理,为新型信号处理机模块板和整机验证提供有效的检测方法。

线性图形的拓扑性质检测算法研究

拓扑性质具有对图形的平移、伸缩、旋转的不变性。因此 ,拓扑性质检测在机器视觉及模式识别领域有十分重要的意义。本文以着色算法为基础 。

ArcGIS拓扑检测在二次调查成果数据缩编中的应用

拓扑是地理要素之间的空间关系,它是确保数据质量的基础。本文主要阐述了ArcGIS的拓扑检测功能,将其应用在第二次全国土地调查核查成果数据缩编项目的检查中,最后详细介绍了拓扑错误的查询与修复的方法。

语义辅助的CityGML模型一致性检测方法

CityGML数据因建模方法、模型优化及数据转换等原因所导致的模型几何、拓扑、语义不一致性广泛存在,影响了对其的进一步应用。本文提出并构建了顾及语义约束的CityGML建筑物模型拓扑一致性规则集,设计了对CityGML LOD2/LOD3/LOD4多细节层次建筑物模型数据进行自动检测与修复的算法,并采用OGC官网公开数据对算法进行了验证试验。试验结果表明,所构建一致性规则集具有较好的完备性,算法能够检测出CityGML建筑物模型数据存在的绝大多数拓扑不一致问题,并能对其中部分的拓扑错误和几何错误进行自动修复。

ArcGIS拓扑检查在地上房屋确权登记中的应用

本文以宁河区农村集体土地使用权及其地上房屋确权登记发证项目为例,介绍项目概况,并对如何运用ArcGIS的拓扑规则检查模块对地籍数据进行检查的步骤和处理的方法进行了探讨。

基于GPS时空轨迹的路网拓扑自动变化检测

充分利用出租车GPS时空轨迹数据分布广和时效性强的特点,提出一种基于车载GPS轨迹数据的路网拓扑自动变化检测新方法。该方法首先利用向量相似性度量模型,度量GPS轨迹向量与路网局部拓扑向量之间的相似性,检测疑似道路拓扑变化点,然后通过比较疑似道路拓扑变化点与路网拓扑关系,完成新增、废弃、改建等道路变化,实现基于车载GPS轨迹的路网拓扑自动变化检测。实验结果表明,该方法不仅有效地检测出道路新增、道路废弃与道路改扩建等变化,而且能利用出租车实时和大范围分布特点来实现城市路网大范围实时变化检测。

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Definitions of Natural-Language Spatial Relations: Combining Topology and Directions

Because SQL for querying data from spatial databa se s is ineffective, the query based on natural or visual language becomes an attra ctive research field gradually. However, how to define and represent natural lan guages related to spatial data are still gigantic problems. Because existing mod els of direction relations can’t describe by use of some common concepts. First of all, detailed direction relations are proposed to describe the directions re lated to the interior of spatial objects, such as "east part of a region","ea st boundary of a region", and so on. Secondly, by integrating the detailed dire ctions with exterior direction relations and topological relations, several NLSR s are defined, such as "a road goes across the east part of a lake", "a river goes along the east boundary of a province", etc. Finally, based on the NLSRs abovementioned, a natural spatial query language (NSQL) is formed to retrieve da ta from spatial databases.

Tip-induced or enhanced superconductivity： a way to detect topological superconductivity

Topological materials, hosting topological nontrivial electronic band, have attracted widespread attentions. As an application of topology in physics, the discovery and study of topological materials not only enrich the existing theoretical framework of physics, but also provide fertile ground for investigations on low energy excitations, such as Weyl fermions and Majorana fermions, which have not been observed yet as fundamental particles. These quasiparticles with exotic physical properties make topological materials the cutting edge of scientific research and a new favorite of high tech. As a typical example, Majorana fermions, predicted to exist in the edge state of topological superconductors, are proposed to implement topological error-tolerant quantum computers. Thus, the detection of topological superconductivity has become a frontier in condensed matter physics and materials science. Here, we review a way to detect topological superconductivity triggered by the hard point contact: tip-induced superconductivity(TISC) and tip-enhanced superconductivity(TESC). The TISC refers to the superconductivity induced by a non-superconducting tip at the point contact on non-superconducting materials. We take the elaboration of the chief experimental achievement of TISC in topological Dirac semimetal Cd_3As_2 and Weyl semimetal Ta As as key components of this article for detecting topological superconductivity. Moreover, we also briefly introduce the main results of another exotic effect, TESC, in superconducting Au_2Pb and Sr_2RuO_4 single crystals, which are respectively proposed as the candidates of helical topological superconductor and chiral topological superconductor. Related results and the potential mechanism are conducive to improving the comprehension of how to induce and enhance the topological superconductivity.

Detection of topological symmetry in the one-dimensional Afeck-Kennedy-Lieb-Tasaki model of integer spin with ultracold spinor atoms in optical lattices

A scheme is proposed for detection of the topology in the one-dimensional Afeck-Kennedy-Lieb-Tasaki model,based on ultracold spinor atomic gas in an optical lattice.For this purpose,a global operation O(θ)is introduced with respect to the breaking of spinrotational symmetry.Consequently,the topology can be manifested unambiguously by identifying the special values ofθwhere the expectation value of the global operator with degenerate ground states is vanishing.Furthermore,experimentallyθcan be detected readily by the interference of ultracold atomic gases.This scheme can be implemented readily in experiment since it does not need the addressing of individual atoms or the probing of a boundary.

High-throughput screening for Weyl semimetals with S_(4) symmetry

Based on irreducible representations(or symmetry eigenvalues) and compatibility relations(CR), a material can be predicted to be a topological/trivial insulator(satisfying CR) or a topological semimetal(violating CR). However, Weyl semimetals(WSMs) usually go beyond this symmetry-based strategy. In other words, Weyl nodes could emerge in a material, no matter if its occupied bands satisfy CR, or if the symmetry indicators are zero. In this work, we propose a new topological invariant v for the systems with S4 symmetry(i.e., the improper rotation S_(4)(≡IC_(4z)) is a proper fourfold rotation(C_(4z)) followed by inversion(I)), which can be used to diagnose the WSM phase. Moreover, v can be easily computed through the onedimensional Wilson-loop technique. By applying this method to the high-throughput screening in our first-principles calculations, we predict a lot of WSMs in both nonmagnetic and magnetic compounds.Various interesting properties(e.g., magnetic frustration effects, superconductivity and spin-glass order,etc.) are found in predicted WSMs, which provide realistic platforms for future experimental study of the interplay between Weyl fermions and other exotic states.