scholarly journals Detecting Covert Networks in Multilingual Groups: Evidence within a Virtual World

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Janea Triplet ◽  
Andrew Harrison ◽  
Brian Mennecke ◽  
Akmal Mirsadikov

This paper introduces an approach for the examination and organization of unstructured text to identify relationships between networks of individuals. This approach uses discourse analysis to identify information providers and recipients and determines the structure of covert organizations irrespective of the language that facilitate conversations between members. Then, this method applies social network analytics to determine the arrangement of a covert organization without any a priori knowledge of the network structure. This approach is tested and validated using communication data collected in a virtual world setting. Our analysis indicates that the proposed framework successfully detected the covert structure of three information networks, and their cliques, within an online gaming community during a simulation of a large-scale event.

2019 ◽  
Vol 220 (2) ◽  
pp. 967-980
Author(s):  
Jack B Muir ◽  
Victor C Tsai

SUMMARY Tomography is one of the cornerstones of geophysics, enabling detailed spatial descriptions of otherwise invisible processes. However, due to the fundamental ill-posedness of tomography problems, the choice of parametrizations and regularizations for inversion significantly affect the result. Parametrizations for geophysical tomography typically reflect the mathematical structure of the inverse problem. We propose, instead, to parametrize the tomographic inverse problem using a geologically motivated approach. We build a model from explicit geological units that reflect the a priori knowledge of the problem. To solve the resulting large-scale nonlinear inverse problem, we employ the efficient Ensemble Kalman Inversion scheme, a highly parallelizable, iteratively regularizing optimizer that uses the ensemble Kalman filter to perform a derivative-free approximation of the general iteratively regularized Levenberg–Marquardt method. The combination of a model specification framework that explicitly encodes geological structure and a robust, derivative-free optimizer enables the solution of complex inverse problems involving non-differentiable forward solvers and significant a priori knowledge. We illustrate the model specification framework using synthetic and real data examples of near-surface seismic tomography using the factored eikonal fast marching method as a forward solver for first arrival traveltimes. The geometrical and level set framework allows us to describe geophysical hypotheses in concrete terms, and then optimize and test these hypotheses, helping us to answer targeted geophysical questions.


Identifying communities has always been a fundamental task in analysis of complex networks. Currently used algorithms that identify the community structures in large-scale real-world networks require a priori information such as the number and sizes of communities or are computationally expensive. Amongst them, the label propagation algorithm (LPA) brings great scaslability together with high accuracy but which is not accurate enough because of its randomness. In this paper, we study the equivalence properties of nodes on social network graphs according to the labeling criteria to shorten social network graphs and develop label propagation algorithms on shortened graphs to discover effective social networking communities without requiring optimization of the objective function as well as advanced information about communities. Test results on sample data sets show that the proposed algorithm execution time is significantly reduced compared to the published algorithms. The proposed algorithm takes an almost linear time and improves the overall quality of the identified community in complex networks with a clear community structure.


Metabolites ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 202 ◽  
Author(s):  
Tara Eicher ◽  
Garrett Kinnebrew ◽  
Andrew Patt ◽  
Kyle Spencer ◽  
Kevin Ying ◽  
...  

As researchers are increasingly able to collect data on a large scale from multiple clinical and omics modalities, multi-omics integration is becoming a critical component of metabolomics research. This introduces a need for increased understanding by the metabolomics researcher of computational and statistical analysis methods relevant to multi-omics studies. In this review, we discuss common types of analyses performed in multi-omics studies and the computational and statistical methods that can be used for each type of analysis. We pinpoint the caveats and considerations for analysis methods, including required parameters, sample size and data distribution requirements, sources of a priori knowledge, and techniques for the evaluation of model accuracy. Finally, for the types of analyses discussed, we provide examples of the applications of corresponding methods to clinical and basic research. We intend that our review may be used as a guide for metabolomics researchers to choose effective techniques for multi-omics analyses relevant to their field of study.


2015 ◽  
Vol 3 (1) ◽  
pp. 93
Author(s):  
Nik Maheran Nik Muhammad

This article advocates that research is lacking on the connection between leadership theory and social network theory. To date, little empirical research has been conducted on leadership and social networks. Thus, the proposition of this article goes beyond traditional leadership models to advocate for a fuller and more integrative focus that is multilevel, multi-component and interdisciplinary, while recognizing that leadership is a complex function of both the organisational leaders and the followers who perform tasks, all of which subsequently leads to decision making qualities. Indeed, the current leadership model focuses on leadership behaviour and the ability to gain followers mutuality, to achieve decision making quality involving the integration of leadership and social network theories. Given the apparent mutable palette of contemporary leadership theory, this emergent construct of the leadership paradigm can expand the poles of the leadership continuum and contribute to a richer and deeper understanding of the relationships and responsibilities of leaders and followers as they relate to decision making qualities. This new construct, which is termed prophetic leadership, explores the literature of the life experiences of the prophet in the ‘Abrahamic Faith’ religion. Drawing on a priori links between the personality trait and spiritual leadership that has recently garnered the interest of scholars, the present study asserts a normative leadership theory that links the personal quality of a leader, posture and principal (based on the Prophet’s leadership behaviour) to synergy and decision making quality. Altruism is proposed to enhance relationships between leadership behaviour and decision making quality. For future research, much work needs to be done specifically aiming to (a) achieve greater clarity of construct definitions, (b) address measurement issues, and (c) avoid construct redundancy.


2015 ◽  
Vol 1 (3) ◽  
pp. 93
Author(s):  
Nik Maheran Nik Muhammad

This article advocates that research is lacking on the connection between leadership theory and social network theory. To date, little empirical research has been conducted on leadership and social networks. Thus, the proposition of this article goes beyond traditional leadership models to advocate for a fuller and more integrative focus that is multilevel, multi-component and interdisciplinary, while recognizing that leadership is a complex function of both the organisational leaders and the followers who perform tasks, all of which subsequently leads to decision making qualities. Indeed, the current leadership model focuses on leadership behaviour and the ability to gain followers mutuality, to achieve decision making quality involving the integration of leadership and social network theories. Given the apparent mutable palette of contemporary leadership theory, this emergent construct of the leadership paradigm can expand the poles of the leadership continuum and contribute to a richer and deeper understanding of the relationships and responsibilities of leaders and followers as they relate to decision making qualities. This new construct, which is termed prophetic leadership, explores the literature of the life experiences of the prophet in the ‘Abrahamic Faith’ religion. Drawing on a priori links between the personality trait and spiritual leadership that has recently garnered the interest of scholars, the present study asserts a normative leadership theory that links the personal quality of a leader, posture and principal (based on the Prophet’s leadership behaviour) to synergy and decision making quality. Altruism is proposed to enhance relationships between leadership behaviour and decision making quality. For future research, much work needs to be done specifically aiming to (a) achieve greater clarity of construct definitions, (b) address measurement issues, and (c) avoid construct redundancy.


Author(s):  
Robert Audi

This book provides an overall theory of perception and an account of knowledge and justification concerning the physical, the abstract, and the normative. It has the rigor appropriate for professionals but explains its main points using concrete examples. It accounts for two important aspects of perception on which philosophers have said too little: its relevance to a priori knowledge—traditionally conceived as independent of perception—and its role in human action. Overall, the book provides a full-scale account of perception, presents a theory of the a priori, and explains how perception guides action. It also clarifies the relation between action and practical reasoning; the notion of rational action; and the relation between propositional and practical knowledge. Part One develops a theory of perception as experiential, representational, and causally connected with its objects: as a discriminative response to those objects, embodying phenomenally distinctive elements; and as yielding rich information that underlies human knowledge. Part Two presents a theory of self-evidence and the a priori. The theory is perceptualist in explicating the apprehension of a priori truths by articulating its parallels to perception. The theory unifies empirical and a priori knowledge by clarifying their reliable connections with their objects—connections many have thought impossible for a priori knowledge as about the abstract. Part Three explores how perception guides action; the relation between knowing how and knowing that; the nature of reasons for action; the role of inference in determining action; and the overall conditions for rational action.


Author(s):  
Donald C. Williams

This chapter begins with a systematic presentation of the doctrine of actualism. According to actualism, all that exists is actual, determinate, and of one way of being. There are no possible objects, nor is there any indeterminacy in the world. In addition, there are no ways of being. It is proposed that actual entities stand in three fundamental relations: mereological, spatiotemporal, and resemblance relations. These relations govern the fundamental entities. Each fundamental entity stands in parthood relations, spatiotemporal relations, and resemblance relations to other entities. The resulting picture is one that represents the world as a four-dimensional manifold of actual ‘qualitied contents’—upon which all else supervenes. It is then explained how actualism accounts for classes, quantity, number, causation, laws, a priori knowledge, necessity, and induction.


Author(s):  
Keith DeRose

In this chapter the contextualist Moorean account of how we know by ordinary standards that we are not brains in vats (BIVs) utilized in Chapter 1 is developed and defended, and the picture of knowledge and justification that emerges is explained. The account (a) is based on a double-safety picture of knowledge; (b) has it that our knowledge that we’re not BIVs is in an important way a priori; and (c) is knowledge that is easily obtained, without any need for fancy philosophical arguments to the effect that we’re not BIVs; and the account is one that (d) utilizes a conservative approach to epistemic justification. Special attention is devoted to defending the claim that we have a priori knowledge of the deeply contingent fact that we’re not BIVs, and to distinguishing this a prioritist account of this knowledge from the kind of “dogmatist” account prominently championed by James Pryor.


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