A simple loan calculator for Android

Decided to try out making mobile applications, here is a first take on a simple loan calculator app for Android.



Now available at Android Market.

Credit: launcher icon was based on a design by Joseph Wain / glyphish.com

Distributed Event Stream Processing with Non-deterministic Finite Automata

Efficient matching of incoming events to persistent queries is fundamental to event pattern matching, complex event processing, and publish/subscribe systems. Recent processing engines based on non-deterministic finite automata (NFAs) have demonstrated scalability in the number of queries that can be efficiently executed on a single machine. However, existing NFA based systems are limited to processing events on a single machine. Consequently, their event processing capacity cannot be increased by adding more machines.

In this paper, we present an experimental evaluation of different methods for distributing an event processing system that is based on NFAs across multiple machines in a cluster. Our results show that careful input stream partitioning gives linear scaleup for CPU bound workloads.

In DEBS'09:
3rd ACM International Conference on Distributed Event-Based Systems
July 6-9, 2009 - Nashville, TN, USA
http://www.debs.org/2009

PDF

Cayuga: A High-Performance Event Processing Engine (demo)

Cayuga: A High-Performance Event Processing Engine (demo). L. Brenna, A. Demers, J. Gehrke, M. Hong, J. Ossher, B. Panda, M. Riedewald, M. Thatte, W. White. In Proc. of SIGMOD 2007, Beijing, USA, June 2007. PDF

Abstract:
We propose a demonstration of Cayuga, a complex event
monitoring system for high speed data streams. Our demonstration
will show Cayuga applied to monitoring Web feeds;
the demo will illustrate the expressiveness of the Cayuga
query language, the scalability of its query processing engine
to high stream rates, and a visualization of the internals of
the query processing engine.

note: I just recently decided to revive this "blog", so this publication is already almost 2 years old.

Currently @ Cornell

I have been appointed a position as Visiting Scientist at Cornell University, and I will be spending the '06/'07 schoolyear in Ithaca, NY. My main supervisor here is Prof. Johannes Gehrke, and I will be working with his team on the Cayuga system.

Automatic Subscriptions in Publish-Subscribe Systems

In this paper, we describe how to automate the process of subscribing to complex publish-subscribe systems. We present a proof-of-concept prototype, in which we analyze Web browsing history to generate zero-click subscriptions to Web feeds and video news
stories. Our experience so far indicates that user attention data is a promising source of data for automating the subscription process.

This paper is to appear in the Proceedings of the 26th IEEE Intl Conf. on Distributed Computing Systems (ICDCS) Workshops, and will be presented on the 5th Intl Workshop on Distributed Event-Based Systems, in Lisbon, Portugal, July 2006.

IJWSP 01/01

The International Journal of Web Services Practices volume 1, issue 1, was published january 2006. It contained my first journal publication, "Engineering Push-based Web Services". it is available online from their site.

Book recommendations from a genius..

Cornells Jon Kleinberg gave a few book recommendations in a recent email interview. With Christmas and all coming up, I thought a link was in order.

Here's the citation:
"Six Degrees, by Duncan Watts, and The Search, by John Battelle, are two good examples; the first covers network theory and social networks, while the second covers the growth of the search industry and what it means for everyday life.

Both are engagingly written, and both succeed marvelously at conveying some of what I was discussing earlier -- the mix of excitement and frustration that comes from doing research in science and technology.

Duncan Watts's book is reminiscent of a very thought-provoking earlier book that I've been recommending to students for a number of years: Thomas Schelling's Micromotives and Macrobehavior. Through a sequence of compelling examples, he illustrates how clever insights and quantitative models can expose the ways in which large-scale social processes are often influenced by very localized mechanisms.

At a more general level, I'd also mention some "classic" collections of biographical essays about famous scientists of the past; for example, Paul de Kruif's Microbe Hunters and E.T. Bell's Men of Mathematics have remained inspirational reading long after they were first written. "

The Future: Push Browsers are Coming (and Needed)

This bold statement was given 3 years ago; yet I don't think we are much closer to a realization. We are seeing Ajax technologies coming into use, presenting new boundaries to what is possible applications in a browser. As we conjecture in the paper "Engineering Push-based Web Services", many applications would benefit from both push-enabled client applications, as well as a network where push is used in combination with pull to optimize network usage.

Google is clearly going to present a push-based browser sometime soon. The scenario depicted by Tyler and Bosworth of BEA Systems clearly coincides with what Google is doing with diverse desktop applications. It becomes even clearer when we know Bosworth got hired by Google last year. My guess is that Google will buy Open Office and let users use it through their browsers.

In the meantime, we are quietly working on the Internet architectures to make such applications computationably feasible. Both in regards to network traffic, but also to user distruption. Wide Area Information Filtering is the Future..

Configuring Push-based Web Services (available online)

My paper to the NWeSP'05 is now available online through our project website.
http://www.waif.cs.uit.no/publications/brenna-nwesp.pdf

Engineering Push-based Web Services

This is basically a longer version of the NWeSP'05 paper, published as a tech report but currently in submission for the IJWSP journal I mentioned earlier.

Tech report available at:
http://www.cs.uit.no/forskning/rapporter/Reports/200555.html

The interactions Web

"The Web ought to be an always-on personal assistant," says Patrick Grady, founder of a Web-based services start-up, Rearden Commerce. "It ought to know who you are and where you are and understand the context of what you're trying to do, and do things on your behalf."

http://www.usatoday.com/money/industries/technology/2005-10-26-internet-service-cover_x.htm

EuroSys Doctoral Workshop 2005

In the fame and glory department, I have also been very lucky to get invited to the first EuroSys Doctoral Workshop in connection with the SOSP 20. Two fellow PhD students here in Tromsø, Steffen V. Valvaag and Håvard Johansen, has also been invited. Steffen is doing a talk in the workshop, Håvard and I are just invited to sit silent and enjoy the show! :)

Looking forward.

NWeSP'5

My visit to Seoul was really great, a good conference with many good papers and clever, friendly participants. My presentation in pdf version is here. The final paper has not yet been published, neither in paper or digitally. Hopefully, this should happen soon.

Based on that article, I have now been invited to contribute to a journal; the International Journal of Web Services Practices (IJWSP). This would surely be a good opportunity for me to expand the paper and get good feedback on the way.