Modeling Transitivity in Local Structure Graph Models

Localized network processes are central to the study of political science, whether in the formation of political coalitions and voting blocs, balancing and bandwagoning, policy learning, imitation, diffusion, tipping-point dynamics, or cascade effects. These types of processes are not easily modeled using traditional network approaches, which focus on global rather than local structures within networks. We show that localized network processes, in which network edges form in response to the formation of other edges, are best modeled by shifting from the traditional theoretical framework of nodes-as-actors to what we term a nodes-as-actions framework, which allows for zeroing in on relationships among network connections. We show that the proposed theoretical framework is statistically compatible with a local structure graph model (LSGM). We demonstrate the properties of LSGMs using a Monte Carlo experiment and explore action–reaction processes in two empirical applications: formation of alliances among countries and legislative cosponsorships in the US Senate.

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Local Structure Graph Discriminant Embedding for Hyperspectral Image Classification

10.1109/igarss47720.2021.9554688 ◽

2021 ◽

Author(s):

Zehua Zou ◽

Fulin Luo ◽

Jiamin Liu ◽

Guangyao Shi ◽

Yufei Liu

Keyword(s):

Image Classification ◽

Local Structure ◽

Hyperspectral Image ◽

Hyperspectral Image Classification ◽

Structure Graph

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X-ray microprobe for materials science

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168013 ◽

1994 ◽

Vol 52 ◽

pp. 56-57

Author(s):

G.E. Ice

Keyword(s):

Crystallographic Orientation ◽

Local Structure ◽

Materials Science ◽

Chemical Information ◽

X Ray Diffraction ◽

Ray Optics ◽

X Ray ◽

Novel Materials ◽

New Information ◽

Elemental Sensitivity

The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. With new x-ray optics these microprobes can achieve micron and submicron spatial resolutions. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature will have important applications to materials science. For example, x-ray fluorescent microanalysis of materials can reveal elemental distributions with greater sensitivity than alternative nondestructive probes. In materials, segregation and nonuniform distributions are the rule rather than the exception. Common interfaces to whichsegregation occurs are surfaces, grain and precipitate boundaries, dislocations, and surfaces formed by defects such as vacancy and interstitial configurations. In addition to chemical information, an x-ray diffraction microprobe can reveal the local structure of a material by detecting its phase, crystallographic orientation and strain.Demonstration experiments have already exploited the penetrating nature of an x-ray microprobe and its inherent elemental sensitivity to provide new information about elemental distributions in novel materials.

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