dimitris kalamaras

math, social network analysis, web dev, free software…

Category: Science Page 3 of 5

SocNetV 1.0 Qt5 is out! RPMs included :)

If you’re interested in Social Networks Analysis and Visualization (I’m not talking about FB/Twitter here!), check out our latest and greatest release of SocNetV, version 1.0.

SocNetV (Social Networks Visualizer) is now based on Qt5/C++ framework and has new great features, such as PageRank network analysis and, of course, layouts. At the moment, there is only source code and Fedora/openSUSE packages available from our project page in SourceForge. Soon, Debian/Ubuntu packages will be released as well. Warning: There are SocNetV packages in the official Debian/Ubuntu repositories, but it’s a very old version. Maybe a brave debian developer (serzan?) could fix this soon 🙂

Needless to say: SocNetV is a GPL3 application. It is free software (free as in freedom). You can copy it, modify it and redistribute it as long as any derivative work remains free software. Enjoy.

Technical documentation for SocNetV

After over a year of project inactivity I’m happy to announce that SocNetV now includes technical documentation for both users and developers. Vaggelis Motesnitsalis, undergraduate in the Computer Science Department of
Aristotle University of Thessaloniki, was kind enough to prepare and contribute a complete Software
Requirements Specification
(SRS, see Wikipedia) document in PDF format for Social Network Visualizer.

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SocNetV on Maemo-N900?

Easy. Short of.

I did this ‘experiment’ to test how much cross-platform Qt really is. I wanted to see if SocNetV can run on Maemo with no modifications whatsoever. These are the steps I followed:

1. Downloaded and installed the Xephyr X11 server (this is a small X11 server that runs inside ‘normal’ X and provides a virtual device screen where you see all the Maemo applications running):

sudo apt-get install xserver-xephyr

2. Downloaded and installed  Scratchbox and  Maemo SDK  in my laptop (Kubuntu x86/lucid).  I followed the straightforward instructions from the Maemo wiki and especially “Installing Maemo 5 SDK on x86-32 Debian based distribution“. It’s only seven steps and circa 100MBs of total downloads…

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SocNetV – 80% completed

Last Friday, it was high time to release a new SocNetV version. The brand new v0.80, the first after six months, marked what I think the start of a more mature period for this tiny little project of mine.

What started as a personal desire to create a simple drawing tool for social networks has become a quite sophisticated tool for social network analysis (spare me, I am talking about mathematical sociology here, not facebook etc):

  • It can read all major network file formats (GraphML, pajek, GraphViz, UCINET, csv, or adjacency matrix) and save the network in GraphML. In the next version, I plan to even add support for the older GML format.
  • It can swiftly compute centrality measures (closeness, betweeness, eccentricity, etc) and layout the network actors accordingly, in radial or layered style, at least for small to medium sized networks (i.e. < 3000 edges). Moreover, it implements one of the fastest known betweeness centrality calculation algorithms. For the 0.90 release, I want to add a couple or more new centrality algorithms (i.e. power centrality by Gil-Mendieta and Schmid).
  • Since 0.70, it can even crawl a given website and create the network of its outLinks. Later, I plan to add support for mailing list archives crawling…

In the new version, I added some social capital features. The software can compute a ‘triad census’, namely it counts all the different types (classes) of observed triads within a network. The triad types are coded and labeled according to their number of mutual, asymmetric and non-existent (null) dyads (this labeling scheme is called M-A-N). This new feature is complimented by a simple, naive (please note, this is a NP-complete problem) clique counting alrorithm.

Also, the speed of the network parser has been improved somewhat by removing some unnecessary checks and adding a simple control variable. And the GraphViz load method is a lot better now. I think. 🙂

As usual, at least a dozen of bugs have been reported and fixed. Of course, it’s not perfect, and certainly many improvements can be made, but the code is there, and is constantly evolving. I think that it deserves to be named 0.80. I am not sure though how easy will be to reach the other 0.20 to the first 1.0 release… If you have an idea about a possible feature, feel free to submit a blueprint.

As usual, source code and binaries for all major distros are available from the project website at SourceForge.

SocNetV 0.70 – the web crawler release :)

It’s been only one month since the release of 0.60, but Social Network Visualizer version 0.70 is here! This summertime release justifies its existence with two new features, a built-in web crawler and multiple node selection.

The web crawler, based on some older tutorial code I had, is pretty simple software (don’t expect Google power here!), which automatically creates mathematical graphs starting with a given URL, called the seed. As the algorithm crawls that seed webpage, it identifies all the links inside the page and adds them to a list of URLs (called frontier). Then, all the URLs from the frontier are recursively visited. In this process, a network of pages (nodes) and links (edges) is being developed allowing the researcher to study and visualize network properties, such as centralities, etc.

At the moment, the web crawler code is quite immature (i.e. doesn’t recognize framesets) but I hope it will evolve in the future. To test it, go to menu Network > Web Crawler (keyboard junkies, press Shift+C). A dialog will appear – enter the initial web address (seed), the maximum recursion level (how many URLs from the frontier will be visited) and the maximum running time and press OK. Here’s a screenshot of SocNetV crawling http://socnetv.org with betweenness centrality radial layout:

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SocNetV version 0.60 says hi!

Happy to report that we released version 0.60 of Social Networks Visualizer (SocNetV) on May 27, 2009. This is a major release bringing:

  • native support for GraphML (this becomes out default load/save format for networks),
  • edge filtering by their weights,
  • new node shapes,
  • lots of bugfixes
  • fresh iconset
  • and a bit of geek cream on top: custom background images.

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Crayon Physics (and what about an open-source Crayon-Physics?)

Crayon Physics is a fascinating 2D physics sandbox/game, which came to my attention today when I was reading  Sarinee Achavanuntakul’s blog entry about the sad HotU (Home of the Underdogs) demise and, more than welcomed, revival.  Sarinee mentioned Crayon Physics Deluxe in her blog post, and I checked it out. What I saw in the flash video was jaw-dropping. Crayon Physics  is not just an indie game, but imho a great educational tool in which you really get to experience “what it would be like if your drawings would be magically transformed into real physical objects”. I wonder, is there an open-source counterpart for creative use of physics?

See the video (2.50min, Vimeo):

Crayon Physics Deluxe from Petri Purho on Vimeo.

Update: There is a wonderful open-source alternative, called Numpty Physics, with lots of different levels. Thanks Mike, for pointing to it.

numptyphysics

Also, nuclear mentioned a physics engine, called chipmunk. Check it out.

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