Why the US Semantics Technology Symposium was a big deal

I recently attend the 1st US Semantics Technology Symposium. I quickly published my trip report because I wanted to get it out asap, otherwise I would never get it out (procrastination!). It’s been a week since my trip report and I can’t stop thinking about this event. After a week of reflection, I realized that there is a big picture that did not come across my trip report: THE US2TS WAS A VERY BIG DEAL!
Why?  Three reasons:
1) There is a thriving U.S. community interested in semantic technologies
2) We are not alone! We have support!

3) Time is right for semantic technologies

Let me drill through each one these points.

1) There is a thriving US community interested in semantic technologies

Before the event, I asked myself: what does success look like personally and for the wider community after this event? I didn’t know what to expect and honestly, I had low expectations. I was treating this event as a social gathering with friends and colleagues that I hadn’t seen in a while.
It was much more than a social gathering. I realized that there was a thriving US community interested in semantic technologies, outside of the usual suspects (academics such as USC/ISI, Stanford, RPI, Wright State, UCSB and industry such as IBM and Franz). At the first coffee break, I told Pascal “I didn’t know there were all these peoples in the US interested in semantic technologies!”. Apparently many people shared the same comment with Pascal. US2TS was the first step, in my opinion, to unify an existing community that was not connected in the US.
I’ve known about the semantic work that Inovex and GE Research have been doing. I was very glad to see them coming to an event like this and publicizing to the wider community about what they are doing.
Very exciting to meet new people and see what they are doing coming from places such as Maine, U Idaho, UNC, Cornell, UC Davis, Pitt, Duke, UGA, UTEP, Oregon, Bosch, NIST, US AF, USGS, Independent Consultants,
Additionally, very exciting to see the different applications domains. Life Science has always been prominent. I learned about the complexity of geospatial and humanities data. I’m sure there are many more similar complex use cases out there.

2) We are not alone! We have support!

The US government has been funding work in semantic technologies through different agencies such NSF, DARPA and NIH. Chaitan Baru, Senior Advisor for Data Science at the National Science Foundation had a clear message. NSF thinks of semantic technologies as a central component of one of its Ten Big Ideas: Harnessing the Data Revolution:
How do we harness the data revolution? Chaitan and others have been working through NITRD to promote an Open Knowledge Network that will be built by many contributors and offer content and services for the research community and for industry. I am convinced that an Open Knowledge Network is key component to harness the data revolution! (More on Open Knowledge Network below.)
Basically, NSF is dangling a $60 million carrot in front of the entire US Semantic Technologies community.
Chaitan’s slides will be made available soon through the US2TS web site.

3) Time is right for Semantic Technologies

Semantic Technologies work! They solve problems that require integrating data from heterogeneous sources where having a clear understanding of the meaning of the data is crucial. Craig Knoblock’s keynote described how to create semantic driven applications from end to end in different application domains. Semantic technologies are key to address these problems.
One of the themes was that we need better tools. Existing tools are made for citizens of the semantic city. Nevertheless, we know that the technology works. I argue that it is the right opportunity to learn from our experiences and improve our toolkits. There may not be science in this effort and that’s fine. I think that is a perfect fit for industry and startups. I really enjoyed talking to Varish and learning how he is pushing for GE Research to open source and disseminate the tools they are creating. Same for Inovex. One of our goals at Capsenta is to bridge the chasm between the semantic and non-semantic cities by creating tools and methodologies. Tools don’t have to come just from academia. It’s clear to me that the time is right industry to work on tools.
One of the highlights of the event was Yolanda Gil’s keynote. Her slides are available at https://tinyurl.com/Gil-us2ts-2018. Yolanda made three important points:
1) The thirst for semantics are growing: We are seeing the interest in other areas of Computer Science, namely, Machine Learning/Data Science (slide 3), Natural Language Processing (slide 4), Image Processing (slide 5), Big Data (slide 6) and Industry through Knowledge Graphs (slide 7). If the thirst for semantics is growing, the question is, how are we quenching that thirst? We are seeing Deep Learning workshops at semantic web conferences. It’s time that we do it the other way: semantic/knowledge graphs papers and workshops at Deep Learning conferences.
2) Supercomputing analogy: In 1982, Peter Lax chaired a report on “Large Scale Computing in Science and Engineering”. During that time, supercomputing had major investments by other countries, dominated by large industry players, limited access to academia and lack of training. The report recommend NSF to invest in Supercomputing. The result was the National Science Foundation Network (NSFNET) and the Supercomputing centers that exist today. This seems like an analogous situation when it comes to semantics and knowledge graphs: major investments by other countries (Europe), dominated by large industry players (Google, etc), limited access to academia (not mainstream in other areas of CS) and lack of training (we need to improve the tools). I found this analogy brilliant!
3) We need an Open Knowledge Network: As you can imagine, to continue the analogy, we need to create a data and engineering infrastructure around knowledge, similar to the Supercomputing centers.  An Open Knowledge Network would be supported by centers at universities, support research and content creation by the broader community, be always accessible and reliable to academia, industry, and anyone, and enable new scientific discoveries and new commercial applications.  For this, we need to think of semantic/knowledge graphs as reliable infrastructure, train the next generation of researchers, and think of the Open Knowledge Network as a valuable resource worth of collective investment.
Do yourself a favor and take a look at the Yolanda’s slides.


This is perfect timing. We have a thriving semantics technology community in the US. Semantic technologies work: we are seeing a thirst for semantics and interest from different areas of computer science. Finally, the NSF has a budget and is eager to support the US Semantic technologies community.

Trip Report: 1st U.S. Semantic Technologies Symposium (#US2TS)

I attended the 1st U.S. Semantic Technologies Symposium (#US2TS), hosted by Wright State University in Dayton, Ohio on March 1-2, 2018. The goal of this meeting was to bring together the U.S. community interested in Semantic Technologies. I was extremely happy to see 120 people get together in Dayton, Ohio to discuss semantics for 2 days. I’m glad to see such a vibrant community in the U.S. … and not just academics. Actually, I would say that academics were the minorities. I saw a lot of familiar faces and met a lot of people from different areas.

The program was organized around the following topics: Cross Cutting Technologies, Publishing and Retrieving, Space and Time and Life Sciences. Each topic had a set of panelists. Each panelist gave a 10 minute talk. There was plenty of time for discussion and a break out session. It was a very lively. The program can be found here: http://us2ts.org/posts/program/

I gave a 10 min version of my talk “Integrating Relational Databases with the Semantic Web: a journey between two cities“. The takeaway message: in order to use semantic technologies to address the data challenges of business intelligence and data integrate, we need to fulfill the role of the Knowledge Engineer and empowered them with new tools and methodologies. Looks like I did a good job at it and it was well received 😃

Two main topics: Ontologies and Tools

Complexity and Usability of ontologies was a topic throughout the two days. Hallway talk is that light semantics is enough (happily surprised to hear this). However, Life Science and Spatial domain need heavyweight semantics (more below). CIDOC-CRM is the ontology used in the museum domain. Apparently very complicated. A lot of people don’t like it but they have to use it.

Linked Open USABLE Data (LOUD): We need to find a balance between usable and complexity.

I was part of a breakout session on ontologies and reuse. I really appreciated Peter Fox’s comment on ontologies (paraphrasing): there are three sides that we need to take into account 1) expressivity, 2) maintainability and 3) evolvability

I shared our pay-as-you-go methodology to create ontologies and mappings in a poster and in hallway discussions. It was well received.

Tools Tools TOOLS: we need better tools. That was another theme of the meeting. There seemed to be an agreement with my claim that the existing tools are made for the semantic city.

JSON-LD came up a lot. People love it.

Application Areas of Semantics

As expected, Life science was present at this meeting. Melissa Haendel from Oregon Health & Science University showed some really cool results that were possible thanks to semantics. Chris Mungall from Lawrence Berkeley National Laboratory gave an overview of the Gene Ontology.

Really interesting to learn that data in the geography domain (spatial data) is complex and requires heavyweight semantics, just like in life science.

Interesting observations about humanities data. I see the need for semantics

I need to check out perio.do: “A gazetteer of period definitions for linking and visualizing data“. One of the project leads is a fellow longhorn, Prof. Adam Rabinowitz. I want to meet him!

Meeting people

Great chatting with Varish Mulwad from GE Research and learning about all the semantic work that is going on at GE Research. Need to check out Semtk (Semantics Toolkit ) and these papers: .

SemTK: An Ontology-first, Open Source Semantic Toolkit for Managing and Querying Knowledge Graphs

Integrated access to big data polystores through a knowledge-driven framework

I enjoy meeting Alessandro Oltramari and learning about the semantic work going on at Bosch.

Great to finally meet Vinh Nguyen. Her PhD was on Contextualized Knowledge Graphs (I should take a look at her PhD dissertation) and she is now organizing an ISWC 2018 workshop on this topic.

Happy Birthday Craig Knoblock!! He gave a fantastic keynote on his birthday!

Glad to have bumped into Ora Lassila. It’s been a long time!!

Future research directions

Take aways from the Meeting

This is an event that was missing in the U.S. I’m glad that it was organized (Fantastic job Pascal and Krzysztof!). Looking forward to this event next year!

My Most Memorable Event of 2017

I travelled a lot in 2017. The most I have ever traveled before. I flew 163,195 miles which is equivalent to 6.6x around Earth. I was on 114 flights. I spent almost 400 hours (~16 days) on a plane. I visited 17 countries: Austria, Argentina, Canada, Chile, Colombia, France, Germany, Greece, Guatemala, India, Mexico, Netherlands, Portugal, Spain, Switzerland, UK, Uruguay. I was in Austin for 164 days (my home), 61 days in Europe, 28 days in Colombia and 16 days in India. I slept 30 nights at a Marriott, 27 nights at an Airbnb and 13 nights on a plane.

Given all this travel, I asked myself: what was my most memorable event of 2017?

The answer was simple: dinner at the Royal Society of London with Bob Kowalski and Keith Clark.

In July, I gave a lecture at the 2017 Reasoning Web Summer School and attended the RuleML+RR 2017 Conference. The conference dinner was at the Royal Society of London. Bob Kowalski gave the dinner speech titled “Logic and AI – The Last 50 Years”. It was the 50th anniversary of when he started his PhD, which gave the rise to logic programming. Additionally, by pure coincidence I sat next to Keith Clark. The combination of sitting next to Keith Clark and listening to Bob Kowalski’s is what made this my most memorable event of 2017


Early during my PhD, my advisor, Dan Miranker, encouraged me to read about the 5th Generation Japanese Project (if you don’t know what this is, go look it up NOW!) During my research, in order to trace back the relationship between Logic and Data, I encountered the landmark 1977 Workshop of Logic and Data Bases organized by Herve Gallaire, Jack Minker and Jean-Marie Nicolas. That workshop is where Ray Reiter presented his paper on Closed World Assumption, Bob Kowalski presented his paper on Logic for Data Description and Keith Clark presented his paper on Negation as Failure. I even have a copy of the proceedings:


Every time I give a talk on this topic, I reference that 1977 workshop to provide historical context of where we are today. See slide 4:

Bob concluded with two open questions:

1) What is the relationship between declarative and imperative representation of knowledge?
2) What is the relationship between different types of rules?

As you can imagine, sitting next to Keith Clark, listening Bob Kowalski’s talk and having the opportunity to chat with them is what made this a truly amazing evening.

With Bob Kowalski
With Keith Clark

What an evening! An evening I will never forget! Thank you Bob and Keith!

Oh, I even saw Alan Turing’s Certificate of a Candidate for Election into the Royal Society.


Mind blown!

ISWC 2017 Trip Report

The 16th International Semantic Web Conference took place from October 21-25 in Vienna, Austria. These are my random thoughts.

First of all, I’m honored to be part of the Organizing Committee as a chair of the In-Use Track, together with Philippe Cudré-Mauroux. Jeff Heflin was the General Chair and a fantastic leader. The conference was impeccable thanks to the AMAZING local organization. Axel Polleres and Elmar Kiesling did an incredible job. I truly enjoyed every step of the process to help organize ISWC 2017. I am really looking forward to ISWC 2018 in Monterey, CA and ISWC 2019 in Auckland, New Zealand!

I was part of a pre-ISWC meeting which a followup with the group that attended the Dagstuhl workshop on Federated Semantic Data Management. We continued defining a list of prioritized research topics.

Frank van Harmelen gave a fantastic keynote at the Semantic Science workshop about the end of the scientific paper.

Btw, if you have the chance to see Frank give a talk… it’s a must! He is one of the best speakers in academia that I have ever seen. I wish I could present like him!

I attended most of VOILA!2017 Workshop. The highlight of the event was the demos. Around 20.

* Next version of VOWL is addressing a lot of needs.
* Check out ViziQuer. It looks cool but I’m skeptical about how usable it is.
* Great to see interest on UIs for generating R2RML mappings but they haven’t been tested yet with real world scenarios. Long ways to go here.
* I need to check out the Linked Data Reactor
* Treevis.net, interesting resource. Need to check it out.
* The extensible Semantic Web Browser
* user, user, user: everybody mentions users but usually the “user” is not defined. Who exactly is your user?

Welcome ceremony was in the Vienna Rathaus. Beautiful place. We were so lucky.

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During the welcome ceremony, we had reencounter of 5 alumni from the 2008 Summer School on Ontological Engineering and Semantic Web: Laura Drăgan, Tara Raafat, Maria Maleshkova, Anna Lisa Gentile and myself with John Domingue and Enrico Motta who were the organizers. We have gone a long ways!

Great discussion about the history of Project halo funded by Vulcan with Michael Witbrock, Oscar Corcho and Steffen Staab. Learned a lot of historic details.

Congrats to Mayank Kejriwal for winning the 2017 SWSA Distinguished Dissertation Award! Mayank and I are academic brothers: we both did our PhD at the University of Texas at Austin under the supervision of Prof Daniel Miranker.

Congrats to DBpedia for winning the SWSA Ten-Year Award. Definitely well deserved!

Industry and In use: If I’m not wrong, approximately 25% of attendees of ISWC were from industry and government (more specifically not from academia). All the industry talk were on Monday. Great to see the room full all of the time. We are definitely seeing more use of semantic technologies. However, my observation is that this is mainly government and research/innovation folks are very large companies. It is not yet replacing the status quo. Additionally, a lot of complaints about the lack of maturity of tools, specially open source tools. I’m not surprised.

Ontology engineering seems to be popular (or it never stopped?). Deborah McGuinness‘ keynote showed real world projects in health care where ontologies play a central and vital role. Takeaway message: it takes a village.

It seems to me that we have had the following evolution in the past decade: first focus on hard core theoretical ontologies (DL and the like), second focus has been more on the data side (Linked Data), third focus (now) is about “little semantics goes a long way”. Jim Hendler has always been right (see my comments below on Jamie Taylor’s keynote).

Is this the year of the Knowledge graph? Are Knowledge Graphs becoming Mainstream? Thomson Reuters announced (by coincidence?) their Knowledge Graph while ISWC was going on. There was no formal announcement during the conference.

Interesting part is that Thomson Reuters built their own RDF graph database (triplestore). Why? See this tweet:

I presented a poster on the Ontology and Mapping Engineering Methodology that we have been using at Capsenta in order to apply semantic web technologies to address data integration and business intelligence pain points. THANK YOU THANK YOU THANK YOU for all the feedback that I received during the poster session and hallway conversations. This is the reason why you go to a conference! Special shoutout to Enrico Franconi and Frank van Harmelen. Conversations with you were extremely insightful.

Jamie Taylor, the former Minister of Information at Freebase (and the person who has had one of the coolest titles) and who now manages the Schema Team for Google’s Knowledge Graph gave the third keynote, which btw, was exactly what you expect for a keynote. Thanks Jamie for such an awesome talk!

His message was very clear: we need actionable and executable Ontologies/Knowledge Graphs. What does this actually mean? The example he gave was the following: in the Google KG, they have assertions that Polio and the Vaccine for Polio, but no where it is asserted that the Vaccine for Polio prevents Polio. This goes into adding common sense knowledge (think about Cyc).  I think it would be fair to say that the lessons learned reported by Jamie were a bit “duh”/“told you so” to this community. My observation is that the giant Google, at the end, is doing what the Semantic Web community has been working on for over a decade. This is good! It was very nice to see the evolution of the Knowledge Graph at Google and insightful to see the practical role that semantics take place. Pascal Hitzler quickly wrote up his take away from Jamie’s keynote.

Congrats to Olaf Hartig, Ian Letter and Jorge Perez for winning the Best Paper Award.

This paper presents foundational work towards understanding what are Linked Data Fragments (LDF) and the relationship between different types of LDF. From a more general point of view, this work helps to formalize the relationship between a Client-Server architecture. Hence it’s applicability is not just within the Semantic Web. This is a beautiful example of how theory and practice can be bridged. Additionally, the presentation was simply brilliant. Jorge Perez has the capability of taking the most complicated concepts and presenting them in a way which is understandable and enjoyable to the audience. I can’t wait to see this presentation on video lectures. When it is published, this is a must see on how to present a paper at a conference. I wish I could present like Jorge!

Daniel Garijo presented his WIDOCO tool. If you work with ontologies, you really need to use this tool which basically is an outsource for the documentation of the ontology. He also received the Best Paper Award for the Resource track. Well deserved!

You can find all the papers of the conference for download on the ISWC 2017 website. No paywall!

The Job Fair was a great addition. Looking forward to seeing its evolution in the upcoming ISWC.

I really enjoyed being part of the mentoring session. It’s great to hear students about what worries them and provide some advice. We discussed paper publishing process, academia vs industry, US vs Europe, dealing with loneliness, and many more topics. Please reach out if you have any questions!

Great to have more Austin presence at ISWC with data.world

who also sponsored the … JAM SESSION! All I can say is:

and without further ado, here is 1+ hour video of the Jam Session, a large group of Semantic Web Computer Scientist PhDs jamming, after just 3 hours of practice. I think this is the definition of epic! Enjoy!


See you next October in Monterey, California for ISWC 2018!

A Weekend in Antigua, Guatemala

In May 2017, Escape ATX shared a deal for Austin to Guatemala for $300! I immediately jumped on it. Last weekend I visited Guatemala, specifically Antigua. This small town used to be the capital of the Kingdom of Guatemala (which included most of Central America) in the 1700s and is now UNESCO World Heritage Site. After the peace was signed in the mid 90s, Antigua started to boom with a lot of tourist but continued to maintain it’s small town appeal.

For me, the best way to summarize Antigua is the following: imagine a typical pueblo in Latin America (in Colombia think Villa de Leyva o Salento) mixed with the cosmopolitan vibe of Austin. Cobble stone roads, colonial style housing, park in the middle of the town with the cathedral in front, with high end luxury restaurants, bars with pub food, local craft beer, hole in the wall bars.

I observed three types of foreigners:
1) tourists
2) short term: foreigners coming for volunteering or “figuring what I want to do with life” who come for months and may end up staying for a year or two
3) resident immigrants: foreigners who have been living in Antigua for many years and are owners of a bar or restaurant

Antigua is a bubble within Guatemala. It is not cheap (same prices as in Austin). But it has a charm, a “no sé que” that wants me to come back. I can see myself going back and working from Antigua for a week or two (who would be interested?)

These are some of the places that I visited which I recommend:

Chermol: Argentinean restaurant. Wide variety of local craft beers

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The Snug: Small irish pub with live music

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Panza Verde: high end restaurant, romantic ambiance. All the food was delicious.

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Cafe No Se: The famous Cafe No Se. It’s been featured in NY Time’s “What to do in 36 hours in Antigua Guatemala”. It’s a hole in the wall, mostly full of foreigners. In the back they have the a mescal bar where they only serve Illegal mescal and beer. Music is blues/soul which reminds me of Thursday night at Barberella in Austin

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Caoba Farms: an organic farm where they have a farmers market every Saturday with local cusine. During my visit they had an Oktoberfest

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Cantina Royal: cool bar

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Saberico: Eat in a beautiful garden. Breakfast was delicious.

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Whiskey Den: Whisky, why not? There are a bunch of other bars next to this one.

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Angie Angie: awesome pizza! Live music. Outside patio is relaxing. On Sunday Pizza is 2×1.

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A Summer of Computer Science, Research, Semantic Web, Databases, Graphs and Travel!

This has been a summer of Computer Science, Research, Semantic Web, Databases, Graphs and a lot of travel! In these past 4 months, I visited 10 countries and traveled over 72,000 miles; equivalent to going around the world 3 times. Whew! This is the summary of my summer travel. 

I attended the 11th Alberto Mendelezon Workshop on Foundations of Data Management. AMW is a scientific event with with a heavy attendance from database theory researchers. The hallway discussions are very insightful. I was the organizer of the Summer School and a presented a short paper titled “Ontology Based Data Access: Where do the Ontologies and Mappings come from?”I had a lot of enlightening conversations with Luna Dong from Amazon (working on creating the Product Knowledge Graph. Semantic web is involved), Julia Stoyanovich who gave a real thought provoking tutorial on Data Responsibility (we should all pay attention to this), Leonid Libkin (Nulls in databases are still an issue). I was thrilled to finally meet Dan Suciu, James Shanahan, Jan Van den Bussche among many other database gurus. It’s always a pleasure to hang out with the chilean database “mafia”: Marcelo Arenas, Pablo Barcelo, Leo Bertossi, Claudio Gutierrez, Aidan Hogan et al. Congrats to the local team for organizing a wonderful event, specially to Mariano Consens!
Buenos Aires
I flew into Montevideo and I was flying out from Buenos Aires. I got to spend a day and a half in this great city. I truly enjoyed it. I will have to come back! Blog post about my 36 hour visit to Buenos Aires will come soon.
San Francisco
I attended Graph Day where I had two talks “Do I need a Graph Database? If so, what kind?” and “Graph Query Language Task Force Update from LDBC”. My takeaways:
– AWS is figuring out what to do with Graphs

– Uber is creating a Knowledge Graph
– Stardog, was the only RDF graph database company there. They are growing and very direct with their material: if you are doing data integration, you should be using RDF.
– Multi-model databases are growing: Datastaxs, ArangoDB, OrientDB, and Microsoft’s latest release of CosmosDB
– New Graph databases: JanusGraph, Dgraph, AgensGraph
– openCypher is really pushing hard to be THE property graph query language standard

I attended the Dagstuhl Seminar “Federated Semantic Data Management”, organized by Johann-Christoph Freytag, Olaf Hartig and Maria Esther Vidal. On my way to Dagstuhl, I had the opportunity to stop in Koblenz to hang out with Steffen Staab.
We had extensive discussions on the state of the art in Federated Query Processing from the traditional Relational Databases and Semantic Web perspectives. The goal was to understand the limitations of current approaches in considering ontological knowledge during federated query processing. Federated Semantic Data Management (FSDM) can be summarized in one sentence: Being able to do 1) reasoning/inferencing over 2) unbounded/unknown sources. A couple interesting open challenges to highlight are the following:
1) Unbounded sources: In traditional federated data management, the number of sources is fixed. In FSDM, the number of sources may not be known. Therefore the source selection problem is harder.
2) Correctness: A relaxed version of correctness may need to be considered, a tradeoff between soundness/completeness and precision/recall.
3) Access control: This is still an open challenge even in traditional federated data management.
This is my third home. I try to swing by Zurich once a year. I spent a weekend at Bodensee and visited for the first time Säntis. I had the opportunity to visited Philippe Cudré-Mauroux at the University of Fribourg. We are the ISWC 2017 In-Use PC Chairs, so we had a face-to-face PC meeting. I also gave my talk “Integrating Relational Databases with the Semantic Web: past, present and future” for the first time. This talk is an 1 hour version of my upcoming lecture at the Reasoning Web Summer School in London.
What’s the best way to get from Zurich to London? Stopping for an entire day in Lisbon of course! Specially when you pay for the ticket with miles and $10USD. This was my first time in Lisbon. I arrived early morning, spent 6 hours walking around this amazing city. I also had the chance to have lunch with Sofia Pinto overlooking Lisbon and discuss ontology engineering! One of the best day layovers I have ever had. I have to come back. Blog post on the visit soon.
I was invited to be a lecturer of the 13th Reasoning Web Summer School (RW 2017). I delivered a half day lecture on Integrating Relational Databases with the Semantic Web. My lecture notes appear as a book chapter in the book Reasoning Web. Semantic Interoperability on the Web. It was great hanging out with good friends Axel Polleres, Andrea Cali. I finally got to meet for the first time Giorgos Stamou. Great conversations with Domenico Lembo on Ontology Based Data Access and Leo Bertossi on Inconsistent Databases and Data Quality. The highlight of this visit, and of my summer, was the conference dinner at the Royal Society where I sat next to Keith Clark and enjoyed a marvelous dinner speech by Bob Kowalski. Blog post on this event soon.
Client work took my all the way to Toronto. First time in Canada! So if it’s hot in Texas, might as well try to spend time in a cooler place. This is a great weekend getaway destination (in the summer): fantastic views, food and beer. I also had the chance to meet up with Mariano Consens and get a tour of the University of Toronto.
The Graph Query Language task force from the Linked Data Benchmark Council (LDBC) organized a face-to-face week meeting in Santiago, Chile to work on the proposal for a closed graph query languages where paths are first class citizens. A full week of hard work (we also had fun). I took advantage of this visit to visit my UT friends Lindsey Carte, Alvaro Quezada-Hofflinger and Marcelo Somos, professors at the Universidad de La Frontera in Temuco. I gave a talk in spanish “Integrating Data using the Semantic Web: The Constitute Use Case”. It is enjoyable challenge to give talks to non-computer scientists.
Back in February I found a Austin-Miami roundtrip ticket for $110. So why not! We discovered the Barrel of the Monks brewery in Boca Raton. This is a must if you are in that area and you like belgium beers!
I was invited to attend the STI Summit in Crete. My first time in Crete, and in Greece (I have never attended ESWC which is usually in Crete). Very intense couple of days talking about the future of Semantic Web research. Afterwards I visited Irini Fundulaki at FORTH and Giorgos Stamou at the National Technical University of Athens where I gave my talk on Integrating Relational Databases with the Semantic Web. I was very impressed with all the work on mappings that has been done in both of these groups. In both cases, the one hour talk turned into hours and hours of fruitful discussions. On my flight to Athens I met a fellow travel geek:72hrJetsettergirl. The next day, we randomly bumped into each other at the Acropolis. The sweet coincidences of life!
I attended the ACM Richard Tapia Celebration of Diversity in Computing. I have been attending this conference for 10 years, since I was a senior in college, all throughout my graduate studies and now has a PhD. This year, I was the Workshop and Panel Chair.  I had the chance to moderated a panel “From Research to Startup” with Rachel Miller from Asana (from theory/crypto research to startup), Kunle Olukotun, (Stanford professor and founder of multiple startups) and Andy Konwinski (PhD from UC Berkley and co-founder Databricks). I also was on another entrepreneur panel with Ayana Howard (Professor at Georgia Tech and founder of Zyrobotics) and Jamika Burge. Both panels had a mix of undergrad, grad students and even faculty interested in learning and entrepreneur experiences. We definitely had an amazing group of panelists. Kemafor Anyanwu Ogan invited me to be on her panel of Data Management for IoT. One of the highlights of the conference is to meet with former and new members of Hispanics in Computing including Manuel Pérez Quiñones (congrats on the Richard A. Tapia Achievement Award for Scientific Scholarship, Civic Science and Diversifying Computing!) and Dan Garcia. We missed you Jose Morales and Patti Ordonez!
I’m writing this post on my way back from Amsterdam. I had the opportunity to meet up with Peter Boncz and talk about Graph Query Language use cases. I also gave my talk “Integrating Relational Databases with the Semantic Web” at the VU Weekly Artificial Intelligence meeting. Great crowd and a lot of great questions. Nice seeing Frank van Harmelen and Javier Fernandez.

The summer is well over. Fall is already in full force in Europe. But it is still feels like summer in Texas.

Is RDF a graph?

A graph consists of a set of vertices (nodes, points) and a set of edges (arcs, lines) between nodes. The common definition is  G = (V, E)  where V representes the set of vertices and E represents the edges between two vertices.

Commercially, there are two specific types of graph data models: Property Graph and RDF Graph.  A property graph is a graph where key-value pairs can be associated to vertices and edges. An RDF graph is a represented as a set of triples: subject, predicate, object where the subject and object are vertices and a predicate is an edge.

However, it seems that Jim Webber, Neo4J’s Chief Scientist does not acknowledge that RDF graphs are graphs:

My response and Jim’s follow up response:

and my response:

It is still unclear to me why Jim Webber believes RDF graphs are not graphs?

Jim, I’m in London this week. I would love to meetup, have a pint and chat about graphs!

Why doesn’t the Database and Semantic Web research community interact more?

I was in Chicago to meet with colleagues from the Graph Query Language task force at the Linked Data Benchmark Council (LDBC) so we could have an impromptu face-to-face meeting (great progress towards our graph query language proposal!). They were in Chicago attending one of the main academic database conferences: SIGMOD/PODS. I was able to take a quick look at papers, demos and tutorials.

I left with the following question: Why doesn’t the Database and Semantic Web research community interact more? The cross pollination, in my opinion, is minimal. It should be much bigger. A couple of examples:

If you go to two conferences of your field in a year, consider swapping one conference to attend another conference in a different field. For example, for the Semantic Web community, if you attend ISWC and ESWC, consider swapping one of those to attend SIGMOD or VLDB. Same for the database community.  VLDB 2017 will be in Munich from August 28th to September 1, 2017.

I made a list of papers from SIGMOD/PODS (research papers, demos and tutorials) that I believe are relevant to the Semantic Web community. The SIGMOD and PODS papers are available online

PODS Papers



SIGMOD Tutorials

P.S. For the travel and points geeks. Last minute travel to Chicago was really expensive. Over $500 USD.  I was able to use 25000 miles and pay just $10 USD. And I even got upgraded to first class!

A Refreshing, No-Fluff, No-Buzzword Perspective on Artificial Intelligence

I encountered this refreshing and excellent summary of Artificial Intelligence by John Launchbury, the Director of DARPA’s Information Innovation Office (I2O). Thanks Frank van Harmelen for posting this!

No fluff. No buzzwords. It is crisp and succinct explanation of the state of AI today and where it is going. Deep learning wasn’t even mentioned!

The quickly summary is that AI up to now can be summarize in two waves:

First Wave: Handcrafted Knowledge which is very good at reasoning but not very good a perceiving the outside world. It is not good for learning nor abstracting.

Handcrafted Knowledge: Enables reasoning over narrowly defined problems. No learning capability and poor handling of uncertainty

Second Wave: Statistical Learning which is good a perceiving and learning but it is not so good for reasoning and abstracting.

Statistical Learning: Nuanced classifications and predication capabilities. No contextual capability and minimal reasoning ability.

The next Wave, noted as Contextual adaptation is where systems can construct explanatory models that explain real world phenomena. 

My take away from this is that GOFAI (Good Old Fashion AI) is still active and relevant and by combining it with Machine Learning, we will enter the next wave of AI which can provide answers to the why (context).

The conclusion of this video is aligned with the takeaway message from Jim Hendler presentation at the 4th Heidelberg Laureate Forum (HLF): we need Human and AI together.

Hope you enjoy watching these videos as much as I did.

Smart Data and Graphorum Conference Trip Report

I attended the Smart Data-Graphorum Conference (January 30 – February 1) in the Bay Area (actually Redwood City). This conference series originally was called Semantic Technology (SemTech) Conference and I have been presenting at it since 2010.

This year, the conference had a cozy feeling with ~250 attendees. I gave two talks:

  • Graph Query Languages: Similar to my Graph Data Texas talk, I gave an update from the Graph Query Language task force at the LDBC. The latest discussions were incorporated in this talk. We have been discussing the idea of having a paths as a datatype and also its own table ( a table for Nodes, Edges and Paths). Additionally, there are two notions of projection: relational vs graph. The slides provide some examples. This is still on going work.

  • Virtualizing Relational Databases as Graphs: a multi-model approach: In this talk I discussed how relational databases can be virtualized as RDF Graphs by using the W3C RDB2RDF standards: Direct Mapping and R2RML. I argue that graphs are cool, and ask if relational databases are cool? If you are  deciding to move from a relational database to a graph database, you should understand the tipping point. I believe virtualization is a viable option to keep your data in a relational database while continuing to take advantage of graph features. However, that may not always be the case.


Additional highlights of the conference

  • I was glad to see a lot of friendly faces. I feel very lucky to that I can always have a chat with Deborah McGuinness and Michael Uschold, two legends in ontologies. It’s always great to see Souri Das from Oracle (and all the Oracle folks from the semantic technology group) and discuss how the W3C RDB2RDF standards are doing. We both agree that we did a good job with that standard and gave a pat on our own backs 🙂 Also great to see Peter Haase, Dean Allemang, Atanas Kiryakov, Bart van Leeuwen, Jans Aasman, Dave McComb and many more.
  • Michael Uschold and I discussed the pragmatics of part-of and has-label semantics. For some situations you want to be generic. For example, it’s easier for a user to just use “has label” for any thing, instead of having to know the exact type of “has label” for a specific thing. Now I understand many of the modeling decisions made in gist. I argue that from a database point of view, query performance is better if you have more specific properties, unless you have some sort of semantic query optimizations.
  • Cambridge Semantics gave a presentation on their in-memory analytics graph database. They presented results using the LUBM benchmark where they claim to have blown Oracle away. Important to note that they used 4x the hardware. Atanas Kiryakov, Ontotext’s CEO was in the audience and rightfully asked why they didn’t use a more up to date benchmark given that LUBM is from 2007. It seems that everybody has been using LUBM (since 2007) so in order to compare to others, they continue to use LUBM. Hopefully they will start using the LDBC benchmarks!
  • I have been aware that Marklogic markets themselves as a document and graph database. I now understand how they represent things underneath the hood. Each entity, with their corresponding attributes and values are represented in a document (key-values). The relationships between the entities are represented as RDF triples.  This makes a lot of sense to me and I can imagine how this can improve query performance to a certain degree.
  • Brian Sletten gave a great talk on JSON-LD. I wish all web developers could see this presentation in order to understand the value of Linked Data. Even though Brian was not able to give his talk on the new W3C upcoming standard SHACL, the Shapes Constraint Language, his slides left a lasting impression. This is the best definition I have ever seen for the Open World Assumption!

  • It was great to see Emil Eifren, Neo Technologies’ CEO again. We discussed history of RDF and Semantic Web (I didn’t know he was a very early user of Jena!). We seem to be in agreement that RDF is great technology for data integration. Anything else graph related, he argues that you should use Neo4J. Not surprising 😛 I was also glad to see that Neo4j is starting to work on formalizing the semantics of Cypher, including making it a closed query language.

This was a great couple of days and hopefully next year we will have more people!