Questions tagged [networks]

Refers to network theory as part of the graph theory. For questions about neural networks, use our [neural-networks] tag.

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what is the probability that a randomly chosen vertex belong to a small component of size S?

I was reading chapter 12 of "Networks: An Introduction Book by Mark Newman" about Random Graph. part 12.6 of the book is about the small components in Random Graph. page 405 equation 12.24 and 12.25 I ...
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5 views

What is constraint and effectivesize in structural holes?

Today, I spent the whole day trying to understand what structural holes in network means. More specifically I want to clarify what the two measurements constraint and effective size means? Is it good ...
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20 views

Why is my correlation matrix dropping that many NA?

I am trying to build a correlation matrix among documents per topic on a Latent Dirichlet Allocation model by text2vec, getting a doc_topic_distr matrix like below, with only first 5 documents, it's a ...
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Compare networks, including centrality measures, clustering/community detection results

Hi my fellow researchers, I am trying to compare two networks based on exactly same group of individuals (179 unique individuals): One network is based on these individuals' meeting data (two-mode/...
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26 views

What is the difference between node clustering and network community detection?

Node clustering algorithms in which we attempt to determine dense regions of the graph based on edge behaviour(either be a distance value or a similarity value). The more similar nodes come together ...
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1answer
32 views

Network analysis: Formal definition of the number of 1st order neighbours of degree 1

I am looking for a formal definition of a network metric I am using in a scientific article. Let $i$ be a vertex in a graph $G$ and $N(i)$ are the first order neighbors of vertex $i$. I am interested ...
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1answer
51 views

Calculating the Expected life of network with hazard functions

I have been asked to solve some questions in the statistical program R. First, I want to find the expected life length (by numeric integration) of a network with 3 parallel components (T1,T2,T3) and ...
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22 views

How can I visualize and cluster weighted graphs in python?

On any ecommerce website, you have options to apply filters to filter out products. For example: So I have data of how many users applied what filters tuples on the website. Which is fetched from ...
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11 views

Null model of a random network formula derivation

This paper generates backbones in a network using a null model. The paper mentions https://arxiv.org/pdf/0904.2389.pdf "The null model that we use to define anomalous fluctuations provides the ...
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43 views

What is the difference of first-order difference and second-order difference in trend analysis?

I have seen that the literature in trend analysis use first-order difference and ...
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21 views

Regression with autocorrelation given by a graph

Supppose I would like to fit a standard regression model of the form $y = \alpha + X \beta + \epsilon$, but my observations come from a networked population (eg. social network). I have the graph $G$ ...
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22 views

Help wrapping my head around an analysis based on social networks

I should preface this with a slight disclaimer. The scenario I have outlined is not actually the data I am working with, it is an analogy that I have created (hopefully accounting for all important ...
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26 views

Summary statistics for bipartite networks

I have a large bipartite network that I would like to summarise. So far, I have found the following summary statistics: Degree centrality Graph density Modularity Nestedness I have not found a ...
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33 views

Reference request: Network/graph topology inference

I am a mathematician looking for a survey/book on methods for inference of graph/network topology (structure). Specifically, the kind of problem I am looking to study is as follows: Given a graph $...
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1answer
45 views

Network analysis - Correlation is positive and significant, but coefficient of simple logistic regression is not significant?

I have an adjacency matrix and another which represents whether the two nodes share an attribute. Consider it like an homophily test. We want to test if the likelihood to form a connect depends on the ...
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2answers
45 views

Missing values in a variable depending on the values of another variable

I'm working on a public procurement dataset where I have information on all the participants that presented offers in 358 tenders. I'm analysing relationships between all the companies of the dataset (...
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2answers
26 views

representative nodes in modular network

I want to find the most representative nodes in each module in a modular network. I have used the Louvain algorithm on my graph and found two main modules. Now I want to know what nodes are the most ...
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23 views

Inclusion of AIC statistic in QAP netlogit regression output

I am using the netlogit function of sna for a QAP regression. The output looks something like the table below. You will see that ...
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1answer
32 views

“Multi-level” social network analysis?

I am very new to social network analysis and working on a project here that I am not sure what's possible to model. I don't want to quite call this multi-level because I am not exactly looking at ...
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1answer
20 views

Finding the effect of nodes on a density heatmap

Let's say I have a geo-tagged dataset of all payment transactions for businesses in a city. I know whether each payment is made by cash or card, and have made a heatmap of where in the city the ...
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Picking the two most distant classes

I have a big multi-label dataset which consist of thousands of classes. I would like to find the best way to choose the two most distant classes, i.e. classes that not only never co-exist but also are ...
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1answer
38 views

How to obtain the statistical significance of a given community structure for a directed network?

So, I have several directed (multi-edged) networks, and within them each node has been assigned to one of seven categories (based on some a priori circumstances). Each category should have a higher ...
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22 views

Visual representation of strong associations of two categorical variables

I have a dataset of one categoric variable "supermarket" for each individual person and multiple "product" categories per person and supermarket. E.g.: Person 1 went shopping in supermarket X and ...
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1answer
64 views

Which regression used for normalized count data

I am working with social network data. I have multiple networks of various sizes and I'm calculating indegree (the number of connections between people) in each of the networks. I've been told to ...
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27 views

Why does a minimum value cutoff in edge values create this shape in the log-log plot of the edge values aggregated to start nodes?

I have a weighted network dataset that looks like this: The prev and curr values contain webpages, and n is the number of times users went from the prev webpage to curr webpage. So, each data row is ...
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68 views

Visualising a networkx graph with vosviewer

I am trying to export a networkx graph into a format that vosviewer can read. When I wrote my graph to gml and pajek via nx.write_gml(G, path) and nx.write_pajek(G, path), vosviewer did not accept the ...
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Combining centrality into one based on same data type

I'm working on a project that involves count data (specifically number of interactions) from multiple different districts in a specific area. Our team has been talking about calculating a few ...
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1answer
21 views

Determining the closeness of nodes by their neighbours

Background I have a directional network that is comprised of two types of nodes, business_sector nodes, and event_type nodes. ...
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2answers
61 views

Order of Conditional Independence Tests

I'm studying the PC algorithm for learning the structure of a Bayesian Network. One of the steps refers to performing several rounds of conditional independence tests of increasing order, zero, first,...
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72 views

How does Kamada & Kawai Force Directed layout algorithm interpret negative edge weights?

In Cytoscape, the Kamada & Kawai Force Directed layout algorithm is able to take negative weights between edges. Does anyone know how it's actually using the sign of these? Is it forcing ...
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1answer
151 views

How to cluster a (directional) dissimilarity matrix with both positive and negative values?

I may be thinking of this incorrectly but what would be the best way to cluster a dissimilarity measure that has direction? For example, if someone had condition A ...
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1answer
32 views

Predict node attribute from network variables

ERGM models the probability of a tie forming in a network. Is there a way of using ERGM, or an equivalent model, where the response variable is an attribute of the node, not a tie? Basically, turning ...
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145 views

Compare the degree distribution of a real networks and multiple random networks

Before the paper real world networks are rarely scale free, studies used to (still do) check for the slope in degree distribution graphs and if the slope fell between 2 and 3, discern that the network ...
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1answer
40 views

shortest path optimization for multiple edge attributes

Say I have a network. The edges each have two attributes: age and height. How might I run a shortest path algorithm that optimizes on both age and height? And could I weight it so that it optimizes 0....
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Compare treatment effects across Levels of aggregation

Suppose I am running an experiment to see if a treatment changes the mean weight of a group of people. Note that I am specifically interested in the mean weight: if half the people get heavier, and ...
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1answer
324 views

Centrality of a directed network with edge weights - Gephi

I have the following network of court judgments in the form of a big network.(50k+ nodes and 100k+ edges with weight values). The size is the number of citations. The idea is that court judgments work ...
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1answer
501 views

Assortativity coefficient in igraph

In the context of Social Network Analysis, I want to compute the homogeneity of different networks for specific attributes. For this case the igraph package contains the method assortativity() to ...
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1answer
42 views

what's the theory foundation of the giant component strategy?

could anyone plz let me know what's the theoretical foundation of the giant component strategy? I have used this technique to get the giant components of a not fully connected graph but i need the ...
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1answer
326 views

Computation of Network Homophily / Heterogeneity

I am quite confused about the calculation of network homophily in network analysis. Right now I am computing the homophily using the following function, which has been written and also described by ...
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23 views

Investigating the change of a network / factorial structure over time

I have several variables (questions from a questionnaire) that regroup into several factors (using factor analysis). However, I would be interested in knowing how this factorial structure changes ...
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52 views

How to measure “cyclicity” of a directed weighted graph?

Say you have a weighted directed graph with (potentially) some cycles in it. You want to have some sort of a measure of how "cyclical" this graph is. The requirements are: This measure C=0 on an ...
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1answer
24 views

How to Cluster Hierarchical Network Data

I have thousands of "small" networks that are strictly hierarchical in nature. Here is an example (some are much deeper, much wider etc) but this is the strict structure: How can one cluster (e.g. k-...
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1answer
211 views

Bayesian Network: Calculate probabillity of child node given all probabillity tables

I have a Question about Bayesian Networks. I have a network with many parent nodes and one child node. I have the probabilities for the parents and for the child. The child node is binary, so there ...
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1answer
34 views

degrees of freedom for t-statistic comparing two networks

I'm reading the following paper on non-parametric standard errors and tests for network statistics - https://www.stats.ox.ac.uk/~snijders/Snijders_Borgatti.pdf by Snijders & Borgatti. When ...
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73 views

Quantifying information loss between a graph and a hypergraph

In some of the literature relating to hypergraph applications, there is an argument about information loss when representing data as a graph compared to a hypergraph. For example, the well known ...
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1answer
51 views

Difference between $2^{nd}$ order random walk and personalized pagerank

I've been recently working with graph sampling, and I can't seem to find useful explanation of the following two aspects. On one side there are pagerank-based algorithms, which converge to a ...
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1answer
110 views

How to generate networks of a certain density?

How can you generate small world or scale-free networks with a certain density, say .3? In the case of random networks it seems easy because an edge is drawn based ...
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51 views

Connectivity vs. density for random, small world and scale-free networks

I am trying to understand a paper by reconstructing the the analyses discussed in the Validation study section, however, I am confused when it comes to how a network metric is used. Specifically, the ...
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153 views

Network modularity for exactly two communities

I have a number of empirical networks that tend to show bipolarization patterns, meaning that there are precisely two communities. In some networks, the two communities are very clearly separated (...
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1answer
64 views

Log-log plot comparison between a random and real world networks

I know that random networks have a bell curve (Poisson distribution) in their degree distribution and scale free networks have a straight line in their log-log plots. However, how do the log-log plots ...