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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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4895143190 · Jun 202019922001200920172026
48 results for terrorist groups

The objective of this research is to enhance performance of Stochastic Gradient Descent (SGD) algorithm in text classification. In our research, we proposed using SGD learning with Grid-Search approach to fine-tuning hyper-parameters in order to enhance the performance of SGD classification. We explored different setti…

2019-02-18abs ↗pdf ↗

New method predicts dynamic relationships in terrorist networks.

problem Dynamic co-evolution of multiplex graphs and nodal attributes in terrorism networks.
method Time-varying stochastic latent factor models with neural network Gaussian processes.
result Superior performance in predicting unobserved dynamic relationships.

Potential violent criminals will often need to go through a sequence of preparatory steps before they can execute their plans. During this escalation process police have the opportunity to evaluate the threat posed by such people through what they know, observe and learn from intelligence reports about their activities…

2019-07-03abs ↗pdf ↗

The increasing accessibility of data provides substantial opportunities for understanding user behaviors. Unearthing anomalies in user behaviors is of particular importance as it helps signal harmful incidents such as network intrusions, terrorist activities, and financial frauds. Many visual analytics methods have bee…

2019-05-14abs ↗pdf ↗

Network detection is an important capability in many areas of applied research in which data can be represented as a graph of entities and relationships. Oftentimes the object of interest is a relatively small subgraph in an enormous, potentially uninteresting background. This aspect characterizes network detection as …

2013-03-22abs ↗pdf ↗

Camera model identification refers to the problem of linking a picture to the camera model used to shoot it. As this might be an enabling factor in different forensic applications to single out possible suspects (e.g., detecting the author of child abuse or terrorist propaganda material), many accurate camera model att…

2019-04-11abs ↗pdf ↗

A new sampling scheme based on DOE improves Shapley value estimation accuracy and speed.

problem Heavy computational burden of calculating Shapley values in large coalition games.
method Design of Experiments (DOE) order-of-addition experimental designs for sampling.
result DOE-based sampling scheme yields more accurate and sometimes deterministic estimates of Shapley values.

New link groups are derived from torus necklaces, connecting braid groups to reflection groups.

problem Understanding the relationship between braid groups and reflection groups.
method Constructing torus necklaces and linking them to braid groups of JJ-reflection groups.
result Link groups of torus necklaces are precisely braid groups of JJ-reflection groups, with meridians as braid reflections.

The study proves super-rigidity of Gromov's random monster group for various types of groups.

problem Super-rigidity of Gromov's random monster group in various group types.
method Proof of morphisms having finite image and introduction of hereditary super-rigidity.
result Gromov's random monster group has super-rigidity and hereditary super-rigidity with respect to certain groups.

We study the structure of the virtual braid group. It is shown that the virtual braid group is a semi--direct product of the virtual pure braid group and the symmetric group. Also, it is shown that the virtual pure braid group is a semi--direct product of free groups. From these results we obtain a normal form of words…

2004-07-23abs ↗pdf ↗

Virtual twin groups map to symmetric groups, revealing automorphism structure.

problem Understanding homomorphisms between virtual twin groups and symmetric groups.
method Using irreducible right-angled Coxeter groups and right-angled Artin groups.
result A complete description of homomorphisms between virtual twin groups and symmetric groups, including the structure of the automorphism group of VTnVT_n.

The study restricts groups in graph of groups structures.

problem Realizing groups as fundamental groups of graph of groups with restricted vertex groups.
method Analyzes restrictions on groups that can be realized and applies to manifold construction.
result Places constraints on groups that can be realized in graph of groups structures.

New Garside structures found for torus knot groups and related braid groups.

problem Finding Garside structures for torus knot groups and related braid groups.
method Introducing a new Garside monoid M(n,m)\mathcal{M}(n,m) for (n,m)(n,m)-torus knot groups and other braid groups.
result New Garside structures for (n,m)(n,m)-torus knot groups and related braid groups are constructed.

Logarithmic separation profile in hyperbolic groups shows hierarchical structure.

problem Understanding hierarchical structure in hyperbolic groups with logarithmic separation.
method Proving groups with logarithmic separation split over cyclic groups and providing counterexamples.
result Not all groups with hierarchical structure have logarithmic separation profile.

We describe a procedure for constructing a generalized Thompson group out of a family of groups that is equipped with what we call a cloning system. The previously known Thompson groups F, V, Vbr and Fbr arise from this procedure using, respectively, the systems of trivial groups, symmetric groups, braid groups and pur…

2014-05-21abs ↗pdf ↗

The study restricts normal subgroups of Kähler groups, proving specific cases and general restrictions.

problem Characterizing normal subgroups of Kähler groups.
method Analyzing embeddings and conjugation actions of surface groups and one-ended hyperbolic groups.
result Restrictions on normal subgroups of Kähler groups, including virtual direct products and surface group properties.

Study fundamental groups of geometric transformation groups using loop spaces.

problem Understanding fundamental groups of geometric transformation groups.
method Use differential forms on loop spaces to prove infinite fundamental groups.
result Proves infinite fundamental groups for specific geometric transformation groups.

We discuss dense embeddings of surface groups and fully residually free groups in topological groups. We show that a compact topological group contains a nonabelian dense free group of finite rank if and only if it contains a dense surface group. Also, we obtain a characterization of those Lie groups which admit a dens…

2006-02-27abs ↗pdf ↗

We exhibit a family of infinite, finitely-presented, nilpotent-by-abelian groups. Each member of this family is a solvable S-arithmetic group that is related to Baumslag-Solitar groups, and everyone of these groups has a quasi-isometry group that is virtually a product of a solvable real Lie group and a solvable p-adic…

2005-07-09abs ↗pdf ↗

The study shows that certain groups can be uniquely identified by their finite abelian summands.

problem Identifying groups based on their finite abelian summands.
method Analyzing hyperbolic groups as graphs of free groups with cyclic edge groups.
result Free products of free and surface groups are profinitely rigid.

In this paper, we briefly review some of the known results concerning the cohomological structures of the mapping class group of surfaces, the outer automorphism group of free groups, the diffeomorphism group of surfaces as well as various subgroups of them such as the Torelli group, the IA outer automorphism group of …

2005-07-15abs ↗pdf ↗

The paper studies actions on Bass-Serre trees and identifies new CC^*-simple groups.

problem Investigating actions of fundamental groups on Bass-Serre trees and their CC^*-algebraic properties.
method Analyzing boundary actions of fundamental groups of graphs of groups on their Bass-Serre trees.
result Identification of new families of CC^*-simple groups, including tubular groups and certain graphs of groups.

In this article we define the twisted product of groups as the generalization of the semidirect product of groups. We will find the necessary and sufficient condition in order that the twisted product of groups to be a group. In particular, for two copies of the same group, the twisted product of group by itself throug…

1997-03-03abs ↗pdf ↗

Study the relationship between orbit braid group and equivariant mapping class group on surfaces.

problem Understanding the relationship between mapping class groups and braid groups with group actions.
method Using the fibration F0GMightarrowF(M/G,n)\mathcal{F}_{0}^{G}M ightarrow F(M/G,n) and exact sequence.
result The conclusion is closely connected with the braid group of the quotient space.

The paper characterizes crystallographic groups derived from virtual braid and twin groups.

problem Characterizing crystallographic groups from virtual braid and twin groups.
method Analyzing quotients of virtual braid and twin groups by their commutator subgroups.
result The quotients of virtual braid and twin groups by their commutator subgroups are crystallographic groups.

New groups are hyperbolic and rigid in mapping class groups.

problem Understanding the structure of Veech groups in mapping class groups.
method Showed that Veech groups are hierarchically hyperbolic and quasi-isometrically rigid.
result Veech groups are hierarchically hyperbolic and quasi-isometrically rigid.