dimitris kalamaras

Αν αγαπάτε τα φυτά (και όχι τα “φυτά”), και δεν το ξέρετε ήδη, στην Κηφισιά γίνεται κάθε χρόνο τέτοιο καιρό μια μεγάλη έκθεση λουλουδιών. Θα τελειώσει νομίζω την άλλη Κυριακή. Ακόμα κι αν δεν είστε της κηπουρικής, είναι χάρμα να πάτε μια βόλτα είτε το απόγευμα μετά τη δουλειά είτε το Σαββάτο. Εμείς πήγαμε χτες και πήραμε τα λουλουδάκια μας: ένα νυχτολούλουδο και ένα φιλάδελφο (philadelfus coronarius) με λευκά άνθη. Πάρτε γεύση:

Filed under:
Life by dimitris

Eleni’s pet project (and vehicle to experiment with social cooking), www.supersyntages.gr, has got a new theme. The new graphical theme, designed and implemented by yours truly, plays with the notion of recipe notes pinned on a corkboard. The frontpage ‘carousel’ is still the old one, but it somehow fitted nice.  I am not a designer but I think it turned out to be a nice idea. Check it out!

New corkboard theme [notice the bottom social toolbar]

Filed under:
Open Source by dimitris

Yeeeeeeeeeeah! I am now yet another proud Nokia N900 owner!

Nokia N900 (Image from NOKIA)

This device runs Linux on an ARM Cortex 600MHz CPU, 1GB RAM and 32GB HDD, and it is more a portable computer than a mobile phone, thanks to its 3.5” touch screen (800×480 resolution) and the embedded keyboard. Right now, my N900 is still charging (minimum 6 hours initial charge I was told!) so I haven’t had the chance to play with it yet, but I plan to explore it tomorrow evening. Stay tuned!

Filed under:
Linux, Open Source by dimitris

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.

Filed under:
Open Source, SNA by dimitris

Yep. Or should I say, phew! After a whole week battling 8 hours the day with Bash script errors, package dependencies (to minimize the ISO size), PDFs, etc, and wasting any single moment of my vacation time, I managed to release Sxolinux 2009.1.

I know, it’s kind of hilarious: we call it 2009.1 just 4 days before the end of this year! But I couldn’t make it faster. Why? Because, for this release we prepared two flavors: the original High School version and a Junior one for Elementary school kids. They have different icon sets, different applications, and different ebooks (PDFs). That really doubled the time needed to test and build. Nevertheless, it was really fun. I hope the end products will be OK as well

So, download, and let your kids have fun! I am getting back to SocNetV, at last.

Filed under:
Open Source by dimitris