Active Scaffold and Inheritance

Had a problem getting two cases of single table inheritance to work in ActiveScaffold so thought I'd document it. Package and Classifier are the ActiveRecord classes.

class ExpressSchema 
  has_many :express_entities, :foreign_key => 'package_id'
end

class ExpressEntity 
  belongs_to :express_schema, :class_name => 'ExpressSchema', 
        :foreign_key => 'package_id'
end

YUML Me for Putting UML on Web

Found a very nice little tool called yUML me for putting UML Use Case and Class figures into your blog or other Web pages.

Semantics For and From Information Models

I gave a presentation at the OMG Semantic Information Day on Thursday of last week. My presentation was actually called Semantics For and From Information Models and was about the use of W3C OWL to add semantics to data exchanges using XML and a follow-on project from NIST with a goal of pushing the STEP community towards semantics/ontologies as a core modeling technology.

The presentations will all be made available online and I'll update this post when they're available.

Demos with Rails, Hobo, ActiveScaffold

Continuing to play with doing demos of engineering applications using Ruby on Rails, and in particular the Hobo and ActiveScaffold frameworks that sit on top of Rails. Hobo is nice as long as you have a fairly simple set of concepts to handle. ActiveScaffold is more flexible, but is also a bit more work (e.g. Hobo builds in users/password where you have to add it to ActiveScaffold yourself).

Used ActiveScaffold on one "real" project at for work, which was just a prototype though, with around 30 concepts in the model and it worked out OK. Still some limitations though. It was the front end for a rules engine (jRules from iLog which was recently bought by IBM) so was an interesting architeture. We had to update the data tables from both the Rails GUI and from Hiberbate from the Java accessing jRules. Oracle Express was the database, which poses some problems of its own (e.g. date support is problematic).

INCOSE Activties with SysML and AP233

A bit of work news ...

At INCOSE over the weekend a workshop was held to start mapping the OMG SysML and ISO AP233 standards together. There's an OMG wiki to track progress. Here's an example SysML diagram:

VMWare Fusion VMs Work on Thinkpad Player

Kept reading on VMWare and found that creating VMs on the iMac using VMWare Fusion then using VMWare Player on my laptop to play them was supported. Tried it and it does work - great. Not sure if my original problem was Fusion V1 vs. V2 or an error on my part when copying from iMac to Thinkpad. Anyway, progress ...

Also found a script that lets you clone VMs. It doesn't work on Fusion (VMs are OS X packages of some sort, not a directory) but it showed me where to rename things and edit names inside files ... which is great. I now have a core Kubuntu 8.04.1 that I can clone and rename for other purpose (e.g. a netbeans VM).

Trying Xubuntu as VMWare Host on Laptop

Needed to reinstall VMWare Server (the free version) on my Thinkpad T61 widescreen so decided to try out Xubuntu (XFCE instead of Gnome/KDE) as the host. Should use a bit less memory and disk space so the VMs should work a bit better, if not noticeably better. The VMServer software wouldn't install properly with Xubuntu 8.10 so reverted to 8.04.1 which is supported per the VMWare Web site.