Sunday, September 16, 2007

QUATIC07 - the academical side

I've attended the last edition of the QUATIC conference, a three-day event on Universidade Nova de Lisboa, in Portugal. My main motivation was to participate on SEDES, a satellite workshop on Software Engineering PhD students. The purpose was to discuss ongoing PhD thesis and receive early feedback on them - while checking out other possibly related ideas and suggestions from the other participants.

I presented my PhD proposal, as it was by the end of July of the present year. It was a good experience, I received lots of appraisal for my chosen thematic, and also lots of critiques on the details of the thesis, my way of explaining things and my presentation. So lets start from the beginning, go straight to the end, then stop! :) (bored readers be warned, this is going to be a long post!)

My PhD thesis proposal is entitled "Offline execution in workflow-enabled Web applications". My goal started a bit broader, at a time where AJAX was starting to make its entrance in the development show-biz, I wanted to make desktop-like Web applications. Soon enough I realized I was foolish, because tens (hundreds?) of tools were immediately born to make Web Apps. look pretty, with lots of drag and drops, image overlaps, you name it. When something like Yahoo! releases their widgets, I can confidently stop trying to do something like that - I'm one student, they are one fully employed - read "payed!" - set of experienced developers. So I refined my goal and picked a real request - to make a Web Application run offline, without requiring external applications and without loosing any work. To do this I identified three main areas, or sub-problems:

  1. Workflow decomposition into offline performable modules;

  2. Offline client generation, and its functionality

  3. Offline work reconciliation with the server

And this was what I had in mind at the time of the short paper submission. I was also invited to present a poster on how my work would affect the industry, with a short talk within the main QUATIC conference. That, off-course, set the stage for more interaction, as my poster was on a mandatory corridor to all participants ;)

Later on, I collected a set of information (from both research and opinions on the conference) that made my thesis improve itself. I'll try to present them here, as succinctly as I can:

  • Workflow decomposition is a relatively known problem, and people like van der Aalst have been working on Colored Petri-Nets (CPN) to work it out. The problem is now reduced to the question "How do I tell if I can perform this activity if I go offline now?". This is not as simple as it may seem, as I must ensure that there is a possible execution flow that won't require other entities online interaction. I also must ensure that I can bring all required data offline, to my laptop - and issues like access control or the amount of information arise here.

  • Offline persistency on a browser is now the purpose of tools such as Google Gears. Client-side generation using a high level language is also attacked by tools and frameworks like Morfik, XML11 or Google Web Toolkit. My problem is now to unify the specification of both online and offline tools into one. Later on I might also have to worry about technical details like client application transfer, shrinking, and a workflow-engine client clone, but not for a few months, for sure!

  • I was told the synchronization scheme I was looking for was already done by the nice guys from Redmond. The Occasionally Connected Systems framework is supposed to handle a local database (SQL Server Everywhere) and all the asynchronous messaging it takes to handle eventual internet failure, small period disconnects, etc, and that would include a nice and efficient merge of all offline data. While this may be true, there are a couple of issues that allow me to stay on the innovative side of the research: 1) The framework is intended to run on desktop-based applications. I assume that eventually Silverlight-based applications could be supported (as they grow the run-time virtual machine and bloat them with even more .NET libraries). But I want Web applications to do the same, and that's not been abridged, as far as I can tell. 2) The OCS framework is able to merge database information. But the types of conflicts I'm targeting are the high-level ones. I'm not interested in the last-edition time-stamp that is different. I'm looking for the product that cannot be bought because the store now is set to open from Monday to Thursday and I can only get there on Fridays. To make things clear, I'm not interested in a data merge algorithm, but in the elegant and simple way to integrate the specification of such kinds of conflicts - and their resolution strategies - within the application domain model and workflow definition.

This was a nice set of input. I was pleased. But I had some other things to fix, not so technical but about my approach to the whole PhD:

  • My sales-pitch - I need to fine-tune my goal statement into something that says "I want to describe a specific solution to a specific problem", and not "I want to solve al world's problems in two years, yay!!".

  • I also must get a supportive example. My example has fallen in the field of the non-problem - that was what I got by making it so simple I could explain it in a corridor walk... So the suggestion is to find a concrete requirement in a concrete (aka, real) system, describe the requirement, describe the problems in the current approach and conclude by suggesting how do we would want to do it.

  • I had to change a lot in what I was expecting to produce. Since I'm aiming for a development methodology (and the necessary framework or tools), I had to clearly state the inputs, outputs, all stages, the applicability/restrictions, the target audience, ad so on and so on. It's a shame there is no standards related to methodology description. I could certainly take advantage of one, now!

I'll post later about my personal experience on the conference - something from my human side :), and also to publish a copy of my thesis proposal. Here's how the poster looked like:
QUATIC poster Edgar Gonçalves

By the way, I have to say I consider myself fortunate, as this short paper is now published in a IEEE Proceedings! So, do you have any more advices, or experiences you'd like to share?