Questions tagged [networks]
Refers to network theory as part of the graph theory. For questions about neural networks, use our [neural-networks] tag.
195
questions
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7 views
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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0answers
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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0answers
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 ...
1
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0answers
24 views
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/...
1
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0answers
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 ...
2
votes
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 ...
1
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0answers
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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0answers
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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0answers
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 ...
1
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0answers
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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0answers
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 ...
1
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0answers
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 ...
2
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0answers
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 $...
0
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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 ...
1
vote
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 (...
1
vote
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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0answers
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 ...
1
vote
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 ...
1
vote
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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0answers
6 views
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 ...
1
vote
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 ...
0
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0answers
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 ...
0
votes
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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0answers
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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0answers
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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0answers
17 views
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 ...
0
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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. ...
2
votes
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,...
0
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0answers
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 ...
-1
votes
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 ...
0
votes
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 ...
0
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0answers
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 ...
2
votes
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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0answers
20 views
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 ...
1
vote
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 ...
1
vote
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 ...
0
votes
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 ...
2
votes
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 ...
0
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0answers
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 ...
3
votes
0answers
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 ...
0
votes
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-...
0
votes
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 ...
2
votes
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 ...
1
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0answers
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 ...
0
votes
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 ...
1
vote
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 ...
0
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0answers
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 ...
2
votes
0answers
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 (...
1
vote
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 ...
