From Nov. 26th to Dec. 1st 2005, I’m be in Houston for ICDM’05 where I’ll present our paper An Optimal Linear Time Algorithm for Quasi-Monotonic Segmentation. For a limited time, my slides are available on the Web.

(If you are a thief, I’ve got two sons guarding my house, so don’t bother.)

I thought I had written a piece about this, but no. So, there you go. Tabs are evil in text files. Why? Because the tab character (\t) has vaguely defined semantics. It means “insert x spaces” where x depends on the text editor and the preferences of the user.

The solution? Tell your text editor to dynamically replace tabs by spaces. For vim, you can achieve this by putting the line “set expandtab” in your file “~\.vimrc” or by typing “:set expandtab” while vim is running. The equivalent should be possible with all good text editors.

Go do it. Configure your text editor properly.

Disclaimer: For some specific file formats, such as make files, tabs are necessary.

It looks like JOLAP is dead. The final specification has been approved on June 15^th 2004. However, to this day, except for Mondrian and Xelopes, I know of no implementation of JOLAP. According this this thread, Oracle has no intention of ever supporting JOLAP.

On the other hand, Oracle doesn’t support nor does it plan to support MDX or derived technologies such as XML for Analysis (XMLA) and more recent specifications. But, you can get MDX support in Mondrian and in SQL Server standard edition or better. I am pretty sure IBM supports MDX and maybe XMLA, but with recent changes in their OLAP product line, I must admit I’m a bit confused.

This leaves us with no cross-platform OLAP query standard. After all these failed attempts, it is very depressing.

Update: Daniel Guerrero from Ideasoft correctly pointed out to be that the current JOLAP spec. has not been published yet as a Final Release, but only as a Final Draft. The Final Draft has been approved in June 2004 (though IBM abstained), and normally, the Final Draft ought to be a Final Release by now, but this didn’t happen. The difference is significant because, right now, the JOLAP license, granted by Hyperion, is for evaluation purposes only. This means you can’t go out and implement JOLAP without risking legal troubles. We can imagine many scenarios on what is happening, but I’ll vote for an Intellectual Property issue.

Oracle has recently made available their Oracle Database 10g Express Edition. Its limitations are that it can only run servers with one processor, with 4GB of disk space and 1GB of memory. It is not sufficient for even a small data warehousing project, but it is great for teaching a class. It is available for Linux and Windows.

Microsoft recently made available for free its SQL Server 2005 Express Edition. Obviously only available under Windows. It lacks enterprise features, it is limited to one CPU, 1GB of memory and 4GB of disk space: basically the same limitations as the Oracle Database 10g Express Edition.

IBM is thinking about doing the same with DB2. Currently, it offers the free Java-based Cloudscape database running on any standard Java Virtual Machine (JVM). They also offer a free PHP-bound version of DB2 called Zend Core available for Linux and AIX, and to be available for Windows.

However, it is not like you are limited to what IBM, Oracle and Microsoft have to offer or have to accept the limitations of their “free” products. There are many good free and open source databases such as MySQL, PostgreSQL, MaxDB, Firebird or Ingres. None of these free alternatives is as powerful as an Oracle database, but if you compare what you can buy with zero dollars, the big guys don’t necessarily come on top.

Thanks to tools like HTML Slidy and S5, you can build nice slide shows using HTML, CSS and some Javascript.

But what if you are lecturing at a distance? Imagine people get to watch you by videoconference while watching your slides. How do they know when to go to the next slide and so on? The solution, I believe, is to use AJAX. With a little PHP or Python based server-side script, you could control which slide must be displayed and anyone looking at your slide show would be automatically moved to the right slide.

That’s it. So simple. Anyone dare try it out? I bet it can be done with 200 lines of PHP and 200 lines of JavaScript, no more.

For extra points, make it so that the administrator can upload a picture (maybe using a webcam) which gets displayed in the right top corner, so that it feels a bit more like a videoconference.