Now blogging at diego's weblog. See you over there!

what my thesis is about

Since one of the starting points will be to talk more about my thesis, here goes the abstract. Maybe I'll start a new site or blog for it, to keep things cleaner (there's a lot of stuff to discuss) but for the moment this will do, and the abstract is as good a place to start as any.

Sorry about the use of the "royal 'we'" but this is pretty much a copy/paste of the abstract from the dissertation. Also, maybe it takes some flights of fancy in terms of possibilities, but that's the point of research, isn't it?

Anyway, here goes:

Self-Organizing Resource Location and Discovery

by Diego Doval (abstract - 30 September, 2003)

Networked applications were originally centered around backbone inter-host communication. Over time, communications moved to a client-server model, where inter-host communication was used mainly for routing purposes. As network nodes became more powerful and mobile, traffic and usage of networked applications has increasingly moved towards the edge of the network, where node mobility and changes in topology and network properties are the norm rather than the exception.

Distributed self-organizing systems, where every node in the network is the functional equivalent of any other, have recently seen renewed interest due to two important developments. First, the emergence on the Internet of peer-to-peer networks to exchange data has provided clear proof that large-scale deployments of these types of networks provide reliable solutions. Second, the growing need to support highly dynamic network topologies, in particular mobile ad hoc networks, has underscored the design limits of current centralized systems, in many cases creating unwieldy or inadequate infrastructure to support these these new types of networks.

Resource Location and Discovery (RLD) is a key, yet seldom-noticed, building block for networked systems. For all its importance, comparatively little research has been done to systematically improve RLD systems and protocols that adapt well to different types of network conditions. As a result, the most widely used RLD systems today (e.g., the Internet's DNS system) have evolved in ad hoc fashion, mainly through IETF Request For Comments (RFC) documents, and so require increasingly complex and unwieldy solutions to adapt to the growing variety of usage modes, topologies, and scalability requirements found in today's networked environments.

Current large-scale systems rely on centralized, hierarchical name resolution and resource location services that are not well-suited to quick updates and changes in topology. The increasingly ad hoc nature of networks in general and of the Internet in particular is making it difficult to interact consistently with these RLD services, which in some cases were designed twenty years ago for a hard-wired Internet of a few thousand nodes.

Ideally, a resource location and discovery system for today's networked environments must be able to adapt to an evolving network topology; it should maintain correct resource location even when confronted with fast topological changes; and it should support work in an ad hoc environment, where no central server is available and the network can have a short lifetime. Needless to say, such a service should also be robust and scalable.

The thesis addresses the problem of generic, network-independent resource location and discovery through a system, Manifold, based on two peer-to-peer self-organizing protocols that fulfill the requirements for generic RLD services. Our Manifold design is completely distributed and highly scalable, providing local discovery of resources as well as global location of resources independent of the underlying network transport or topology. The self-organizing properties of the system simplify deployment and maintenance of RLD services by eliminating dependence on expensive, centrally managed and maintained servers.

As described, Manifold could eventually replace today's centralized, static RLD infrastructure with one that is self-organizing, scalable, reliable, and well-adapted to the requirements of modern networked applications and systems.

Posted by diego on November 30, 2004 at 6:36 PM

location, location, location

First, the support I've received in the last 24 hours is regarding my post on clevercactus amazing and heartening. When I collect myself I'll be more specific, for for now I just wanted to mention this.

One of the comments I've heard most since yesterday has to do with the funding thing. As Dave said, "Consumer focused companies are always difficult to get funding for in Europe". I can definitely attest to that. Lots of enterprise and "vertical" focus, and generally low tolerance for the risk/opportunity equation presented by those opportunities. To their credit, VCs are very candid about this, so it's not as if it's a secret or anything.

One thing we tried to get across is that we'd be totally open to moving to the US if that's what it took to get funded. We'd have no problem with that. But then again, not being there, it's hard to get in the door.

But the "virtuous cycle" created by Silicon Valley is hard to beat. One of the conclusions I will take away from this experience is that all the talk about the "Indian Silicon Valley" or "European Silicon Valley" or "[Insert geolocation here] Silicon Valley" is just plain ridiculous. There isn't a place like it in terms of investors, press, talent, etc., all deeply interconnected (well, maybe a couple of places in the US come close, namely the Seattle/Redmond area, Route 128, and NYC). I remember going to Il Fornaio in Palo Alto and just feeling it. It's where things happen. (Plus it ain't a bad place to eat).

So: there's only one Valley, the rest are close, but no dice. :)

Categories: clevercactus
Posted by diego on November 30, 2004 at 5:35 PM

where to begin?

I've been up for more three hours now (woke up at 5 or so, that's what I get for going to sleep at midnight), and I've been thinking more about what to write and/or do in the next couple of weeks, aside from looking for the next big thing. As you can imagine I'm sort of in a bit of a hole right now and I think the best way to climb out of it is to get moving.

So... let's see.

  • I want to talk about my thesis work, now that the whole process is basically over (I picked up the bound copies of the dissertation last Friday, they look great). There's a ton of stuff there, but to begin with, the title of the thesis, is Self-Organizing Resource Location and Discovery. :)
  • Ideally I'd spend a bit of time coding something interesting and totally, absolutely, positively unrelated to what I've been doing for the last two and a half years. Reading (and re-reading) weblogs today, looking for some inspiration, I came across this post from Don Park in which he talks about the idea of creating a conversation category, to formalize (structure? make more "solid"?) a bit the tenuous links between cross-weblog conversation threads. I need to think a bit about that today. Anne's Forgetting Machine concepts are enticing, and with a cool name to boot, but when I think about that my brain keeps dragging itself into Gibsonesque (or maybe Stephensonesque) vistas of the datastream where bots run around forgetting where they've been and asking for directions. Entertaining, but not something I'd be able to code in a few days.
  • I'd also like to write up what I've learned, what my experience was with clevercactus. But I need a few days for that. Minimum. Will revisit that next week.
Okay. That sounds like a good starting point no?

Categories: personal
Posted by diego on November 30, 2004 at 7:09 AM

ads in rss - not as easy as it sounds?

Last week Jeremy was talking about ads in RSS and how it seems a foregone conclusion that they will, eventually, become the norm. I agree that this is more likely than not, but I doubt that today's web ad infrastructure (as understood by what Yahoo!, Google, do) will be used directly.

The reason why I say this was actually mentioned by Jeremy, but not explored. While talking about the options (full text with ads, summaries without), he said:

I don't want to have to choose between ad-laden full-content feeds and the pain in the ass summary only feeds. Anyone whose ever tried to catch up on their reading while on an airplane or train gets this.
The problem with ads in RSS lies in the second sentence: "Anyone whose ever tried to catch up on their reading while on an airplane or train gets this."

Many RSS readers are web-based, and those would always work for web ads (unless a plugin is added to stop them, see below). But many, many RSS readers are rich clients, and clients will sometimes be working in disconnected mode.

"Disconnected mode" throws a wrench in the ad-serving business model, by either preventing the download of the ad, or preventing clickthrough.

If that's the case, then how do you serve the ads? You could embed them into the content, sure, but then you'd have the problem of a) showing relevant/uptodate ads, b) measuring ad-views and c) allowing click-throughs, which are impossible while disconnected.

Someone might say that most people are wired most of the time, and so this problem is minimal. But I have no doubt that, were ads in RSS to become pervasive, rich clients would include a simple way of working in "disconnect mode" (and those that don't would fall behind those that do), not to speak of plugins that would surely be developed, both for clients and browsers, just like adblock exists for Mozilla.

If the readers were to be integrated into the ad serving-viewing-clicking cycle (keeping stats, allowing clickthroughs, etc), then maybe things would be closer to web ads, but who is to say that users will not flock to RSS readers that will support the "ad-free" mode? Or modify their ad-friendly readers?

So even though ads in RSS might be just around the corner, I'd bet that they (and the business model behind them) will have to change at least a bit--the current way in which web ads work probably won't be enough.

Categories: technology
Posted by diego on November 30, 2004 at 6:57 AM

the drive to discover


In the latest issue of Wired magazine, James Cameron has a great article, The Drive to Discover. Reminds me of this post I wrote a little over a year ago.

Also in the latest Wired, lots of other great exploration-related articles, such as The New Space Race by Bruce Sterling and Taming the Red Planet, by Kim Stanley Robinson, author of the Mars trilogy (Red Mars, Blue Mars, and Green Mars).

Categories: science
Posted by diego on November 30, 2004 at 6:34 AM

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