Opossum is the fastest OWL-S matchmaker in the 3rd International Semantic Service Selection Contest, having the best query response time with regards to the seven contest entries. As far as I know, this is the only benchmark for semantic Web services matchmaking, which makes Opossum the fastest in the world! More about the indexing technology that made Opossum fast can be found in this article (PDF).

Matchmakers were tested for speed and accuracy,and while Opossum had won the speed category, it is not one of the three top matchmakers for accuracy. Well, maybe next time . I will add a link to the results summary when it becomes available.

Its been long overdue, but the British PM issued today a public apology to Alan Turing. On popular media, and in Gordon’s public note, Alan Turing is mentioned mainly for his contribution to the breaking of the German code in WW2. However, in my mind, his most profound contribution is to the structure of computers. Every computer we use today, every router and machine that enables you to read this blog post, is structured almost perfectly according to Turing’s design. His work was not merely technical. It was a breakthrough. He introduced an elegant and simple design, which did not change very much in the last 60 years. The human kind will be forever in debt to Turing for this contribution.

The mechanism that led Turing to his death, for the single reason of being gay, is a dark stain on our society. Gordon’s apology is important because this is not a problem of days past. It is a current problem. A month ago, an unidentified man had shot gay teens in a community center in Tel Aviv. Two of them were killed. In the U.S., gays are thrown out of the army if they do not hide their identity. All over the world, people are forced to hide in shame or to suffer grieve consequences. This is exactly the choice that Turing had faced. Admitting that this is wrong is an important step.

Google maps is using anonymous location data from Google maps applications
on mobile phones in order to infer real time traffic conditions.

This is a lovely implementation, but it raises some privacy concerns. For example, law authorities could request the information from Google. While the information is declared as anonymous, it has been shown that location data can be easily De-anonymized.

Google allows users to opt-out of the service (here is how). However, it seems that the only way to opt out from the service is by stopping location services in Google maps completely – something that most users would hesitate to do.

Locaccino has a new Symbian client, working on Nokia phones such as N97, e51 etc. It will update your location on the server, while staying in the background, allow you to check your friends’ location, to see who has viewed you, who can view you, allow you to go offline and more.

To use it, first go to Locaccino and add the facebook application. Afterward, go to Locator and go on from there.

My search engine for semantic Web services is back online, this time on a more reliable server: http://opossumsearch.org/

Some techno-based mythical mambo jambo in a New York times article about computerized, high frequency, stock trading.

High-frequency traders often confound other investors by issuing and then canceling orders almost simultaneously. Loopholes in market rules give high-speed investors an early glance at how others are trading. And their computers can essentially bully slower investors into giving up profits — and then disappear before anyone even knows they were there.

That is a little too dramatic, maybe. One interesting question, is there a mahematical proof that high frequency can yields high revenue? Is it based just on exploiting some technical loopholes or is there something more fundamental here?

Sometimes, its funny to see how red and green color codes are used in software. As red/green schemas are basically taken from traffic lights, we can imagine that red would be used for dangerous situations (stop!) and green for safe situations (move on). Like in Microsoft’s personal firewall:

But sometimes, color codes are basically used for what’s good for the software service. For example, in Brightkite, a location-sharing application, this is how full location disclosure (posted to a public web page) looks like:

and this is how a private mode, which is “safe” looks like:

So, can people trust these color codes? Probably not.

Osnat's trail in the park

. Osnat’s trail in the park, as seen on Locaccino

Recently, a paper by Aviv Segev and me was accepted to IEEE Transactions on Services Computing. The article, with the rather long name of “Context-Based Matching and Ranking of Web Services for Composition” tries to challenge a simple problem. Given a Web service in WSDL (short documents that describe Web services) and a set of ontology domains, to which ontology domains does this service belongs, and how strong is this “belongness”.

The simple solution is to take the words in the WSDL, to take the words in the ontology, and to compare them. This is how documents are classified to topics in a text corpus. The problem is that the WSDL documents, that describe Web services, contain very little text. At the worst case, they can contain just the names of the input and output parameters. In this paper, we searched for a solution on the Web. We took the words form the WSDL descriptions and thrown them to search engines. We collected words from the results, and ranked these words according to the number of times they appeared for different elements of the service. For example, if a service input parameter was “zip” and the output was “address”, and running these words in a search engine returned words such as “location” (due to both zip and address) and “compression” (due to zip, such as in win-zip), we ranked “location” higher than “compression”. We then took those words, added them to the WSDL words and used all of them in the comparison process.

We had compared our method to simple string matching, to tf/idf and to a number of other methods. We found out that our method and tf/idf composed together outperformed other every single method.