MCS+ : An Efficient Algorithm for Crawling the Community Structure in Multiplex Networks

2021 ◽  
Vol 16 (1) ◽  
pp. 1-32
Author(s):  
Ricky Laishram ◽  
Jeremy D. Wendt ◽  
Sucheta Soundarajan

In this article, we consider the problem of crawling a multiplex network to identify the community structure of a layer-of-interest. A multiplex network is one where there are multiple types of relationships between the nodes. In many multiplex networks, some layers might be easier to explore (in terms of time, money etc.). We propose MCS+ , an algorithm that can use the information from the easier to explore layers to help in the exploration of a layer-of-interest that is expensive to explore. We consider the goal of exploration to be generating a sample that is representative of the communities in the complete layer-of-interest. This work has practical applications in areas such as exploration of dark (e.g., criminal) networks, online social networks, biological networks, and so on. For example, in a terrorist network, relationships such as phone records, e-mail records, and so on are easier to collect; in contrast, data on the face-to-face communications are much harder to collect, but also potentially more valuable. We perform extensive experimental evaluations on real-world networks, and we observe that MCS+ consistently outperforms the best baseline—the similarity of the sample that MCS+ generates to the real network is up to three times that of the best baseline in some networks. We also perform theoretical and experimental evaluations on the scalability of MCS+ to network properties, and find that it scales well with the budget, number of layers in the multiplex network, and the average degree in the original network.

Author(s):  
Ricky Laishram ◽  
Jeremy D. Wendt ◽  
Sucheta Soundarajan

We examine the problem of crawling the community structure of a multiplex network containing multiple layers of edge relationships. While there has been a great deal of work examining community structure in general, and some work on the problem of sampling a network to preserve its community structure, to the best of our knowledge, this is the first work to consider this problem on multiplex networks. We consider the specific case in which the layers of a multiplex network have different query (collection) costs and reliabilities; and a data collector is interested in identifying the community structure of the most expensive layer. We propose MultiComSample (MCS), a novel algorithm for crawling a multiplex network. MCS uses multiple levels of multi-armed bandits to determine the best layers, communities and node roles for selecting nodes to query. We test MCS against six baseline algorithms on real-world multiplex networks, and achieved large gains in performance. For example, after consuming a budget equivalent to sampling 20% of the nodes in the expensive layer, we observe that MCS outperforms the best baseline by up to 49%.


2021 ◽  
Author(s):  
Anatoliy Gruzd ◽  
Ksenia Tsyganova

This article examines how online groups are formed and sustained during crisis periods, especially when political polarization in society is at its highest level. We focus on the use of Vkontakte (VK), a popular social networking site in Ukraine, to understand how it was used by Pro- and Anti-Maidan groups during the 2013/2014 crisis in Ukraine. In particular, we ask whether and to what extent the ideology (or other factors) of a particular group shapes its network structure. We find some support that online social networks are likely to represent local and potentially preexisting social networks, likely due to the dominance of reciprocal (and often close) relationships on VK and opportunities for group members to meet face-to-face during offline protests. We also identify a number of group-level indicators, such as degree centralization, modularity index and average engagement level, that could help to classify groups based on their network properties. Community researchers can start applying these group-level indicators to online communities outside VK; they can also learn from this article how to identify networks of spam and marketing accounts.


2021 ◽  
Author(s):  
Anatoliy Gruzd ◽  
Ksenia Tsyganova

This article examines how online groups are formed and sustained during crisis periods, especially when political polarization in society is at its highest level. We focus on the use of Vkontakte (VK), a popular social networking site in Ukraine, to understand how it was used by Pro- and Anti-Maidan groups during the 2013/2014 crisis in Ukraine. In particular, we ask whether and to what extent the ideology (or other factors) of a particular group shapes its network structure. We find some support that online social networks are likely to represent local and potentially preexisting social networks, likely due to the dominance of reciprocal (and often close) relationships on VK and opportunities for group members to meet face-to-face during offline protests. We also identify a number of group-level indicators, such as degree centralization, modularity index and average engagement level, that could help to classify groups based on their network properties. Community researchers can start applying these group-level indicators to online communities outside VK; they can also learn from this article how to identify networks of spam and marketing accounts.


Author(s):  
Ginestra Bianconi

This chapter presents the existing modelling frameworks for multiplex and multilayer networks. Multiplex network models are divided into growing multiplex network models and null models of multiplex networks. Growing multiplex networks are here shown to explain the main dynamical rules responsible to the emergent properties of multiplex networks, including the scale-free degree distribution, interlayer degree correlations and multilayer communities. Null models of multiplex networks are described in the context of maximum-entropy multiplex network ensembles. Randomization algorithms to test the relevant of network properties against null models are here described. Moreover, Multi-slice temporal networks Models capturing main properties of real temporal network data are presented. Finally, null models of general multilayer networks and networks of networks are characterized.


2014 ◽  
Vol 23 (3) ◽  
pp. 132-139 ◽  
Author(s):  
Lauren Zubow ◽  
Richard Hurtig

Children with Rett Syndrome (RS) are reported to use multiple modalities to communicate although their intentionality is often questioned (Bartolotta, Zipp, Simpkins, & Glazewski, 2011; Hetzroni & Rubin, 2006; Sigafoos et al., 2000; Sigafoos, Woodyatt, Tuckeer, Roberts-Pennell, & Pittendreigh, 2000). This paper will present results of a study analyzing the unconventional vocalizations of a child with RS. The primary research question addresses the ability of familiar and unfamiliar listeners to interpret unconventional vocalizations as “yes” or “no” responses. This paper will also address the acoustic analysis and perceptual judgments of these vocalizations. Pre-recorded isolated vocalizations of “yes” and “no” were presented to 5 listeners (mother, father, 1 unfamiliar, and 2 familiar clinicians) and the listeners were asked to rate the vocalizations as either “yes” or “no.” The ratings were compared to the original identification made by the child's mother during the face-to-face interaction from which the samples were drawn. Findings of this study suggest, in this case, the child's vocalizations were intentional and could be interpreted by familiar and unfamiliar listeners as either “yes” or “no” without contextual or visual cues. The results suggest that communication partners should be trained to attend to eye-gaze and vocalizations to ensure the child's intended choice is accurately understood.


2013 ◽  
Vol 14 (3) ◽  
pp. 115-133
Author(s):  
조현 ◽  
Jaeshin Park ◽  
ki-jin jang

2008 ◽  
Vol 11 (4) ◽  
Author(s):  
Katrina A. Meyer

Thirteen students in a graduate-level course on Historical and Policy Perspectives in Higher Education held face-to-face and online discussions on five controversial topics: Diversity, Academic Freedom, Political Tolerance, Affirmative Action, and Gender. Students read materials on each topic and generated questions for discussion that were categorized by Bloom’s taxonomy so that the level of questions in the two discussion settings would be closely parallel. Upon completion of each discussion, they answered questions that addressed depth and length of the discussion, ability to remember, and a self-assessment of how the student learned. Students’ assessments show a consistent preference for the face-to-face discussion but a small number of students preferred the online setting. However, what is perhaps more interesting is a minority of approximately one-third of the students who perceived no difference between the settings, or that the two settings were perhaps complementary.


Trictrac ◽  
2018 ◽  
Vol 10 ◽  
Author(s):  
Petru Adrian Danciu

Starting from the cry of the seraphim in Isaiahʹ s prophecy, this article aims to follow the rhythm of the sacred harmony, transcending the symbols of the angelic world and of the divine names, to get to the face to face meeting between man and God, just as the seraphim, reflecting their existence, stand face to face. The finality of the sacred harmony is that, during the search for God inside the human being, He reveals Himself, which is the reason for the affirmation of “I Am that I Am.” Through its hypnotic cyclicality, the profane temporality has its own musicality. Its purpose is to incubate the unsuspected potencies of the beings “caught” in the material world. Due to the fact that it belongs to the aeonic time, the divine music will exceed in harmony the mechanical musicality of profane time, dilating and temporarily cancelling it. Isaiah is witness to such revelation offering access to the heavenly concert. He is witness to divine harmonies produced by two divine singers, whose musical history is presented in our article. The seraphim accompanied the chosen people after their exodus from Egypt. The cultic use of the trumpet is related to the characteristics and behaviour of the seraphim. The seraphic music does not belong to the Creator, but its lyrics speak about the presence of the Creator in two realities, a spiritual and a material one. Only the transcendence of the divine names that are sung/cried affirms a unique reality: God. The chant-cry is a divine invocation with a double aim. On the one hand, the angels and the people affirm God’s presence and call His name and, on the other, the Creator affirms His presence through the angels or in man, the one who is His image and His likeness. The divine music does not only create, it is also a means of communion, implementing the relation of man to God and, thus, God’s connection with man. It is a relation in which both filiation and paternity disappear inside the harmony of the mutual recognition produced by music, a reality much older than Adam’s language.


Author(s):  
Mary Cavanagh

The face to face interactions of reference librarians and reference assistants are studied from a theoretical practice perspective. Rather than reinforcing professional boundaries, the results of this analysis support reference practice in public libraries as a highly relational activity where reference “expertise” retains a significant subjectivist, relational dimension.Les interventions en personne des bibliothèques de référence et des adjoints à la référence sont étudiées du point de vue de la pratique théorique. Plutôt que de renforcer les frontières interprofessionnelles, les résultats de cette analyse appuient l'idée que les pratiques de référence en milieu public sont des activités hautement relationnelles où l'expertise de la référence conserve une dimension subjectiviste et relationnelle. 


IFLA Journal ◽  
2021 ◽  
pp. 034003522110182
Author(s):  
Evans F Wema

This article reviews literature on the use of virtual learning environments by highlighting their potential and the challenges of introducing the same in Tanzania. It introduces the concept of virtual learning environments by demonstrating their applications to support teaching and learning. The article discusses the use of virtual learning environments in teaching information literacy courses by highlighting the success of using such tools in facilitating the teaching of information literacy courses to library users. In this review, special emphasis is placed on attempts by Tanzanian institutions of higher learning to introduce web-based teaching of information literacy and the challenges faced. The review reveals the need for Tanzanian institutions of higher learning to develop virtual learning environments to facilitate the teaching of information literacy courses to students and faculty so as to reach many of those who may not manage to attend the face-to-face information literacy sessions that are offered by librarians on a regular basis.


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