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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4k views

2SLS with endogenous interaction term

I am trying to estimate a peer effects model where a certain characteristic of the individual and the peers might be endogenous: $$\ y_i=\alpha + \beta_1 Controls_i + \gamma_1 Endog_i +\gamma_2 \...
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4answers
2k views

Graph clustering algorithms which consider negative weights

I have a graph instance with weighted directed edges which values can be in range [-1,1]. I need to do clustering on this graph, in order to find out groups in which vertices are more correlated. I ...
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0answers
763 views

Pagerank vs Eigenvector centrality

What are the practical differences between PageRank and Eigenvector centralities? I don't mean the differents in how to compute the centralities, but the information they provide of a set of nodes in ...
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1answer
405 views

Betweenness values for nodes different in SNAP and iGraph network analysis packages?

I compared results from using the SNAP (Stanford Network Analysis Project) Python library and the iGraph R library for analyzing networks. The betweenness values for nodes seem to be rather different ...
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2answers
4k views

How to test statistically whether my network (graph) is a “small-world” network or not?

A small-world network is a type of mathematical graph in which most nodes are not neighbors of one another, but most nodes can be reached from every other by a small number of hops or steps. ...
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1answer
107 views

Normalised distance measure to compare distributions

Network generation parameters are to be optimised to produce spatial networks that match a given degree distribution (discrete: negative binomial) and a given continuous distance distribution (...
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1answer
296 views

Regression-like models for spatial point processes restricted to a network or grid

I am working on a spatial analysis of traffic accidents, the goal of which is to estimate the effects of spatial covariates on the intensity function of crashes. The original analysis was an ...
3
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1answer
400 views

Comparing adjacency matrices

I have 25 weighted adjacency matrices which can be potentially translate into 25 networks. I want to see how ``similar'' are the resulting networks (in a graph theory sense). Is there a way to do ...
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1answer
699 views

Community detection (graph clustering) of a weighted graph with node attribute (categorical or quantitative)

Consider a weighted graph having node attributes. Say the nodes are birds and the attribute could be either categorical (gender) or quantitative (number of feathers), i.e. similarly to this example. ...
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1answer
65 views

One-mode network (data transformation)

I'm looking for a solution to perform network analysis among my data set. My database is shaped like this : Table 1 : ...
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0answers
52 views

how to quantify the dependence between two sparse signals?

Hi and thank you for your help. I am happy to provide more context/details. In my research, I have a system that has many sensors X_1..X_N and using this ...
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0answers
75 views

Dividing power law distribution

Most of the social communities follows power law distribution. I have data for 3 communities from stackexchange websites. Number of posts , answers by users follow the power law distribution. There ...
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1answer
168 views

Accepted notation for sparsity/density of a network

Is there an accepted notation in the study of network structure for the measure of network sparsity and/or density? For example, I see $\rho$ is typically used for spectral radius, $\alpha$ for leak ...
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134 views

Test whether cross-sectional dependence in panel data follows known (network/spatial) structure

I want to test whether cross-sectional dependence in one specific variable (y) in panel data format follows a known structure (W) (e.g. network, spatial dependence), after controlling for individual ...
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1answer
355 views

XERGM R-package: GOF error with bipartite, temporal ERGM

I was able to estimate the following temporal, bipartite ERGM using the xergm package in R: ...
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0answers
350 views

Comparing factor structure to network analysis using a community detection algorithm

I am interested in the use of weighted correlational network analysis to explore high dimensional data, instead of latent variable models like exploratory factor analysis (EFA). My approach is to: ...
2
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1answer
108 views

How to find out is the difference between two social networks based on their assortativity significant?

I've got two networks and I want to prove somehow that one of them is more homophilic not by chance.
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2answers
99 views

Ill-posed covariance matrix

I have a gene expression matrix $A$ with dimension $7000\times 30$ where $A_{ij}$ represents the expression of gene i at time j. I need to make a gene co-expression network but the problem is the $...
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1answer
961 views

What is the difference between graphs/networks? [closed]

Note: read down to below "Question" to find the question. Background: In a previous question I asked how to group what I would call nodes on a network graph based on a connectivity matrix. (link) ...
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0answers
94 views

Missing values with Community structure in networks?

Is there a way to predict Missing values with Community structure in networks? I have a data set with a couple dozen variables, such as age, level of education, self-assessed (via a Likert scale) ...
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0answers
47 views

Relationship between P(A|X,Y), P(X|Y) and P(A|X)?

My statistics training is only basic, so forgive any embarrassing misunderstandings. Here's my situation: I have a graph (a big one) with 20,770 nodes. This is Y. I have a subgraph, X (subset of Y),...
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3answers
411 views

Network centrality in a set of networks with shared nodes

I have a set of weighted networks, each represented as a complete graph composed of nodes and connections with weights (see also "weighted networks" on Wikipedia). All networks share the same nodes ...
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1answer
50 views

Has deconvolution been applied to nodes in a sensor network?

Convolution, and blind deconvolution, is generally applicable where there is some "truth" function describing a physical process, and then some kind of distortion. I have a bunch of sensors in a ...
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0answers
292 views

Borgatti Key Player Problem (KPP) in Python

Has anyone come across any Python implementation of Borgatti's proposed Key Player Problem (KPP) algorithms? I'm interested in solutions using NetworkX and particularly interested in implementations ...
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1answer
58 views

Survey analysis: relationship between one discrete outcome variable and multiple categorical and ordered categorical variables

I have a data set that is the result of a survey. The survey asks the respondents to name 5 people in their community whom they turn to for advice. It then goes to these 5 people and asks the same. I ...
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1answer
20 views

Identify search strategy over network

Imagine a website. Each page is a vector, each hyperlink an edge. Many people connect to this website. I collect the pages visited and the links clicked. The data-set is made up of all these "paths" ...
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1answer
2k views

How do I define the number of parameters needed to specify this Bayesian network?

If it is known that Bayesian network has one root node, one node with a single parent, two nodes with two parents and the remaining nodes with 3 parents, indicate how many parameters would be required ...
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2answers
189 views

Tournament Plotting: Who is good against whom?

I would like to get insight into who is good against whom. Imagine a tournament setting* of 40 contestants and you're interested in seeing who is good against who in the top 10: how could we make this ...
3
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1answer
151 views

Connections between groups in a hive plot

In a Hive Plot nodes are placed on lines and connections between groups are highlighted. This plot seems to lose the connections between nodes on the same line. It seems like an intentional loss of ...
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0answers
974 views

Plot directed acyclic graph with scaled edge length

I am trying to design a network (more precisely a directed acyclic graph) with specific edge lengths. The data is on the form of an edge list, and for each edge, there is an associated length. It ...
2
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0answers
64 views

More than one function of a single instrumented endogenous variable — is the model still underidentified?

The typical instrumental variable setup seeks a consistent estimate of $\beta$ from $$ y = \alpha + \beta x + \epsilon $$ where $cor(x,\epsilon) \neq 0$, in the univariate case, without loss of ...
3
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1answer
953 views

Financial exposures modelling with graph theory tools

I was wondering how finance folks go about storing and modelling portfolio exposure relationships with the aim to later aggregate or slice & dice the exposures by different factor sets. For ...
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0answers
63 views

Comparing networks of groups of unequal size

I want to compare some network properties such as entropy, connectivity, etc., between 2 groups. I have time series fMRI data on patients (n = 80) and controls (n = 30) for certain regions of the ...
2
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1answer
706 views

How do multi-attribute edge-weights influence community detection?

My graph consists of a computer network topology where each vertex is a physical node/device (depicted using its IP address). Two vertices will have an edge if the nodes have had communication with ...
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2answers
96 views

Identifying middlemen in a social network

I have a data set and I want to examine an hypothesis in there and probably Network Analysis should prove or reject my theory. I have a list of products and a group of people who give the product to ...
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2answers
36 views

aggregating multiple shortest-path networks

I have a dataset of 500 observations (firms) and for each firm I know how they are directly and indirectly related based on some characteristics. I can therefore construct a network of connectivity ...
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1answer
122 views

MPNet output to visualization

I've been using igraph and statnet to do most of my network analysis, but I am trying to replicate results that I use MPNet (an expansion to PNet) in order to perform some simulations on a multi-level ...
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0answers
81 views

What is a proper scale to do the social network analysis?

Problem My problem is to profile the individual user (i.e. mine individual user's interest, location, and many more). What we have as input are the network structure (e.g. linked-in network) ...
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0answers
500 views

Network graph: hypothesis test that degree distribution is becoming more equitable

I'm playing around with network graphs and am wondering how to show that there is: a statistically significant difference in in-degree distribution between nodes for 2 time periods the in-degree ...
2
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2answers
390 views

Two-mode weighted network edge weight normalization

I have a two-mode network which looks into relationship between forum threads. Two forum threads are connected if the same user has replied to both. The nodes are sized based on number of people who ...
2
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2answers
4k views

Reliability of a network

Consider the communication network shown in the figure below and suppose that each link can fail with probability p. Assume that failures of different links are independent: All links are ...
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0answers
391 views

Multivariate meta-analysis in R: how to investigate network of variables [closed]

I would like to conduct a meta-analysis to investigate the interaction of three variables:hair color (dark/light), gender (male/female) and size (continuous). I have three studies reporting effect ...
2
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1answer
1k views

What are the algorithms to detect bots clicking on a shortened URL? [closed]

I own a url shortening service. I want to deliver only legitimate statistics to my clients. There are possible scenarios that a particular user writes a script to automatically open the shortened URL, ...
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0answers
189 views

Comparing groups of different sizes in social network analysis

I've got social network data for three groups of chimpanzees and I'm looking to do some basic analysis across and between groups. Does anyone by any chance know how to compare social network data ...
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3answers
4k views

Does Newman's network modularity work for signed, weighted graphs?

The modularity of a graph is defined on its Wikipedia page. In a different post, somebody explained that modularity can easily be computed (and maximized) for weighted networks because the adjacency ...
2
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1answer
54 views

How can you construct a social network empirically from multiple sources of data

Let's say you have databases $A$ and $B$, and a population of users $\left\{u_1,\ldots,u_n\right\}$. You're building a social network graph of $\left\{u_1,\ldots,u_n\right\}$. From database A, you ...
3
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1answer
639 views

Interaction effects in network meta-analysis (multiple treatment comparison) in R?

I would like to use network meta-analysis (or multiple treatment comparison) to investigate the main-effect and interaction of two factors on a continuous outcome variable. As an example the effect of ...
11
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2answers
770 views

What does it mean when all edges in a real-world network/graph are statistically just as likely to happen by chance?

I've been using the backbone network extraction method outlined in this paper: http://www.pnas.org/content/106/16/6483.abstract Basically, the authors propose a method based in statistics that ...
3
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0answers
57 views

Relations and differences between graphical models and stochastic networks?

Do both graphical models and stochastic networks (e.g. http://people.cs.pitt.edu/~milos/networks/) mean the same concept: there is an underlying graph, each vertex corresponding to a random variable, ...
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1answer
211 views

A statistical model for a sample of independent networks

Based on the lack of responses to my previous network question, perhaps this is not quite the place to ask this question, but I'll give it a try. I am planning a series of studies that involve small ...