Life on Mars

So, I’ve finished my Ph.D work at RPI, and am going to try to re-emerge on this weblog. Which is something I’ve attempted before (several times!) with mixed success, so we’ll see how it goes.

Bora Bora

Kat and I (mostly Kat so far) are also posting updates to a travel weblog as we spend six months going around the world. I’ve been putting photos from our trip on Flickr, and highlights will be included in our weblog posts.

Cherry Blossoms

So far, we’ve been to Alaska, Hawaii, French Polynesia, New Zealand, Australia, and Japan. It’s been pretty fast-paced, but we’ve seen and done some great stuff. If you’re interested, you can follow along from the beginning.

Earlier this week I spent a few days at the Preikestolen Mountain Lodge at the Moving to Moose hackathon. I got to meet some great people from the perl5 and perl6 communities, hack on the perlrdf toolkit, and see a couple of great talks.

Lysefjord Cairn

Along with other members of the perlrdf community, I worked on updating our RDF toolkit (RDF::Trine) to use the Moose object system. Chris Prather helped us settle on a design that will simplify code, allow for easy implementation of new parsers, serializers, and stores, and provide a way for implementors to greatly improve the quality of SPARQL query plans produced by RDF::Query.

Ruben Verborgh did some amazing optimization work (with help from Shawn Moore and dtrace) on the pure-perl Turtle and N-Triples parser that yielded two orders of magnitude improvement in parsing speed on some large inputs.

Toby Inkster started converted the classes for nodes and statements to use Moose. Konstantin Baierer worked on modeling the type system in Moose allowing coercion of common objects and unboxed types to their RDF object equivalents. Together they went on to improve the extensibility of the parsing and serializing code, which will make it easier to support custom file formats in the future.

Kjetil Kjernsmo refactored several modules meant to manage XML namespaces into the new URI::NamespaceMap package.

Overall I’m thrilled with the progress we made, and think the new design will allow us to keep improving our code and growing as a community. If you’re interested in more information, join us on irc or the mailing list.

I cannot believe it’s been over 10 years since Pekka Himanen wrote:

As it stands now, watching television characteristically elicits a feeling that what is being seen must be meant as some kind of absurd parody of what television could be at its worst.

— The Hacker Ethic

Case in point.

The 10th International Semantic Web Conference took place last week in Bonn, Germany, and it was a great event.

Beethoven

On Tuesday, I presented my work (done with Jesse Weaver) on HTTP caching of SPARQL query results. The work seemed to be well received, and I had some good discussions about it after the presentation.

There were presentations on two interesting projects for benchmarking SPARQL systems. The DBpedia SPARQL Benchmark (which won the best research paper award) is a new SPARQL benchmark based on real-world data and queries from the DBPedia endpoint. FedBench, meanwhile, attempts to benchmark federated SPARQL query evaluation using a set of both real and synthetic datasets (including a subset of the LOD cloud and SP2B). With the relatively impoverished state of existing SPARQL benchmarks, I’m thrilled to see new work going on in this area.

I spent quite a bit of time with people from Talis, DFKI, and DERI, and only wish there had been more time for the great conversations that took place at and after the conference. I’ve posted some photos from ISWC on Flickr.

Mark Cuban:

So be Patriotic. Go out there and get rich. Get so obnoxiously rich that when that tax bill comes, your first thought will be to choke on how big a check you have to write. Your 2nd thought will be “what a great problem to have”, and your 3rd should be a recognition that in paying your taxes you are helping to support millions of Americans that are not as fortunate as you.

— The Most Patriotic Thing You Can Do

More of this, please.

Zumwalt

I spent a few days in Kings Canyon National Park with the family last week. The river was just past its high water mark, and the valley was amazing.

Grizzly Falls

More photos on Flickr of Kings Canyon National Park.

Notre-Dame Basilica Alter

Notre-Dame Basilica Organ

On a spring break weekend in Montréal, we took a tour of the Notre Dame Basilica.

STS-131 Launch

I went to see the launch of Space Shuttle Discovery in Florida a couple of weeks ago and am finally getting around to posting a few pictures. The actual launch happened just before dawn, so the it was mostly a big fireball in an otherwise dark sky, but it was awesome and my camera was able to pull out some dawn light a few minutes after launch (that’s Discovery in the photo above about 300 miles downrange from Cape Canaveral). The shuttle is scheduled to land back in Florida tomorrow morning, and with only three flights left I’m really glad I got to witness a launch before the shuttle program ends.

Trying to get back into the habit of posting here. I’m just back from two weeks of Semantic Web-related travel. First was roughly a week in northern Virginia for the International Semantic Web Conference, followed by a meeting of the SPARQL working group at the W3C Technical Plenary in Santa Clara, California. Lots of good stuff going on recently; I’ve tried to highlight some of it below.

Jesse presenting our Billion Triples Challenge work

Our work on RDF querying on supercomputers was recieved with much interest at the SSWS workshop. Lots of good questions were asked about the approach, and I hope I provided reasonable answers to them (though I think I could have done a better job in presenting the techniques to avoid some of the resulting confusion). The big news was that our Semantic Web Challenge entry (combining the parallel RDF query work, Jesse’s parallel RDFS materialization work, and Medha’s BitMat work) won in the Billion Triples track.

Jesse and I had some good conversations with Jacopo Urbani about his MapReduce-based reasoning system, its similarity to Jesse’s reasoning work, and the overlap with the parallel query answering work (in the context of extending their systems to handle more expressive reasoning).

Members of the SPARQL working group had what I thought was a good panel Q&A at ISWC about what’s coming in SPARQL 1.1. There was some good input (and criticism) of what we’ve got so far, and I hope we can follow up on many of the points made including the issues of efficient federated querying and atomicity versus full ACID trasactions (we discussed some of these issues at the meeting in Santa Clara).

The RDF indexing in Parliament (also presented at SSWS) looked interesting (especially the “average case analysis” that explains some of the tradeoffs of the design and why the design is good for many real-world datasets). Unfortunately, the SSWS proceedings seem to link mistakenly to a draft version of the paper. I’ve put some more thoughts on Parliament and its impact on our clustered RDF query engine on the Tetherless World blog: Parliament, storage density, and napkin math.

Golden Gate Bridge

Leigh Dodds produced a good looking vocabulary at VoCamp DC for Describing SPARQL Extension Functions. Seems like it would mesh nicely with the SPARQL service descriptions we’re working on for SPARQL 1.1.

Expressing Statistics with RDF does a nice job of explaining how to use the SCOVO vocabulary to describe statistical data. I’ve been using SCOVO to encode statistical descriptions for the data.gov datasets with some success (though I hear the voiD folks are working on a less verbose way to do dataset descriptions).

Silk looks like a great tool to do linking between datasets, and something I hope we can look at for the data.gov RDF work.

Finally, while sitting in on the SPARQL meeting in Santa Clara, Dave Beckett designed a very nice diagram explaining the SPARQL 1.1 Query Execution Sequence. It captures the conceptual ordering of the operations involved in a SPARQL 1.1 query (including aggregates) and I assume maps nicely to many actual implementation (certainly it does to mine).

Claims made during my recent visit to the Providence Apple Store “Genius” Bar where I sought advice on my MacBook Pro not being able to sleep subsequent to upgrading the operating system to Snow Leopard (instead cycling rapidly between being asleep and awake):

1. No Apple laptop should ever be put to sleep while not connected to an external power source.
2. No Macintosh computer will sleep if any running application is trying to access the network.

After explaining my problems (which included the sleep issue, iSync [which I haven’t seen since 10.4!] starting every few minutes, and screen artifacts), the “genius” tole me that I could damage my laptop by letting it sleep without the external power source plugged in. Putting that aside for now, and insisting that that wasn’t my problem, he had me boot the system and immediately upon seeing several menu bar accessories and many icons on the desktop immediately told me that I had lots of “third party software” installed, that much of it was probably incompatible with Snow Leopard, and that it wasn’t his job to troubleshoot that sort of thing for me. He speculated that VMWare Fusion (which he referred to as Parallels) was causing the problem, but couldn’t (or wouldn’t) make an attempt to find out if VMWare Fusion was known to cause problems in Snow Leopard.

After pressing hard about not wanting to just be told to go home and make sure all my applications were compatible with Snow Leopard only to discover it was a deeper problem, he gave in and rebooted my system in safe mode. The sleep problem persisted. He then plugged in an external disk and boot the system into what I believe was Snow Leopard (but which he referred to as 10.5) and the sleep problem disappeared.

At this point, he suggested that it was clearly a problem with my “third party applications” (a term he used many, many times as if to suggest that I was somehow out of the mainstream by running any applications not provided by Apple, and the use of which made my seeking technical support a waste of his time), and that a clean install was the solution. He continued to tell me that my laptop wouldn’t ever sleep if any running application were “trying to access the network.” To this last point I told him he was wrong, but he insisted that any application trying to access the network would wake the computer from sleep. Clearly trying to argue this point wasn’t a good use of my time.

As a final attempt to make his point, he started Activity Monitor, and sat watching the CPU usage graph for a couple of minutes and told me that “there’s a lot of programs running for an idle system.” I resorted the process list by CPU usage and pointed out that the only processes which were actively running (and not sleeping) were mdworker, activitymonitord, and kernel_task, all Apple-provided processes. There was not real response to this, he asked what Tweetie was, and then reiterated that I was just going to have to perform a clean install.

By this point I wasn’t confident that my iSync or screen artifact issues could be resolved by spending any more time at the genius bar. So for the time being, I’m stuck having to turn my computer off completely any time I need put it away from more than a few minutes, stuck having to dismiss iSync from trying to connect to a mobile phone which I haven’t used in years, and dreading the reappearance of screen artifacts. This whole experience has soured me a bit on the Genius Bar. I’ve had such great experiences in the past, making this one all the more surprising and frustrating.