Comments on: Projection http://toreopsahl.com Wed, 22 May 2013 10:51:12 +0000 hourly 1 http://wordpress.com/ By: Tore Opsahl http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-18289 Tue, 12 Mar 2013 22:43:54 +0000 http://toreopsahl.com/?page_id=3112#comment-18289 Hi Martin,

Great to see more open science being done! I’m not sure there is a specific theory I can point you too regarding projects as there is so many. For example, two-mode networks with people and events can be projected due to assumed temporal geographical co-location. However, I believe it really depends on your context which theories of connectedness would apply.

Best,
Tore

]]> By: Martin Grandjean http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-18286 Tue, 12 Mar 2013 21:46:22 +0000 http://toreopsahl.com/?page_id=3112#comment-18286 What a great description! I’ve just published a “state of my research” on my blog (www.martingrandjean.ch/analyse-de-reseau-cartographier-lactivite-de-la-societe-des-nations/) and as a historian (passionate about network analysis but without maths studies) I was wondering how to justify theoretically this “projection”. Thank you for these keys!

]]> By: Tore Opsahl http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-15572 Mon, 21 Jan 2013 20:37:58 +0000 http://toreopsahl.com/?page_id=3112#comment-15572 Hi David,

Great suggestion. It does sound like a good idea as differences in tie weights would discount the tie strength. I haven’t implemented this type of projection method for two-mode networks; however, if you connect with me by email, this code can easily be created.

Best,
Tore

]]> By: David Fisher http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-15362 Thu, 17 Jan 2013 14:24:40 +0000 http://toreopsahl.com/?page_id=3112#comment-15362 Hi Tore,

Great blog, this section in particular is my go-to guide to two-mode networks.

I am interesting in using the geometric mean, instead of the sum, to calculate the strength of an interaction between 2 nodes when projecting a 2-mode network onto a one-mode network.
The strength of the interaction between nodes A and B in the above example (leaving out Newman’s correction for now) would be 2 in this case (or 4.24 if you sum the weights directed at nodes they share before taking the geometric mean).

Do you think this is sensible, and can it be done in tnet?

Cheers

David

]]> By: Tore Opsahl http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-10690 Wed, 31 Oct 2012 13:49:23 +0000 http://toreopsahl.com/?page_id=3112#comment-10690 Hi Mary,

Glad you found it useful. I am not entirely sure what you are referring to when you mention neighborhood measures. However, if you would like to calculate the number of common nodes between primary nodes in a two-mode network, you can use the projecting_tm(net, method=”sum”). This function will produce pairs of primary nodes (columns 1 and 2) with a third column with the number of common nodes.

Best,
Tore

]]> By: Mary http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-10683 Wed, 31 Oct 2012 05:48:16 +0000 http://toreopsahl.com/?page_id=3112#comment-10683 Hi Tore,
Thank you for your article. I was looking for something which would be illustrative and precise. And your article is just that. I am currently working on a two mode bipartite network. Do you know how I can use neighborhood measures like Common Neighbors in the bipartite setting? Thanks

]]> By: Snehal http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-9354 Mon, 17 Sep 2012 22:35:11 +0000 http://toreopsahl.com/?page_id=3112#comment-9354 Thanks Tore for your reply. Yes, at this point, I am considering that primary and secondary nodes are connected if they share a tertiary node. And, the number of common tertiary nodes is captured in the tie strength. Interestingly, given the nature of my original data, primary and secondary nodes are only connected to a tertiary node (women attending event, women having some sort of expertise). So I guess the 2nd question hasn’t been an issue with this dataset.
Best
Snehal

]]> By: Tore Opsahl http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-9350 Mon, 17 Sep 2012 18:33:27 +0000 http://toreopsahl.com/?page_id=3112#comment-9350 Hi Snehal,

Thanks! I have not directly worked with 3-mode networks, so I haven’t given too much thought. I think this is an exciting area of new research with many unanswered questions. Do you project from 3-mode to two-mode by connecting primary and secondary nodes connected to the same tertiary nodes? What do you do with existing connections between primary and secondary nodes?

Best,
Tore

]]> By: Snehal http://toreopsahl.com/tnet/two-mode-networks/projection/#comment-9252 Thu, 13 Sep 2012 23:16:00 +0000 http://toreopsahl.com/?page_id=3112#comment-9252 Hi Tore

Great resource particularly for weighted 2-mode networks.

I am working with 3-mode networks and figured that I’ll have to convert (project) it to 2 modes to get some measures. Can you suggest any literature that deals with this conversion? Right now I am just replicating the 2->1 mode procedures. Your comments/suggestions are greatly appreciated.

Thanks!

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