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Trip Report: ESWC 2019

June 28, 2019
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From June 2 – 6, I had the pleasure of attending the Extended Semantic Web Conference 2019 held in Portorož, Solvenia. After ESWC, I had another semantic web visit with Axel Polleres, Sabrina Kirrane and team in Vienna. We had a great time avoiding the heat and talking about data search and other fun projects. I then paid the requisite price for all this travel and am just now getting down to emptying my notebook. Note to future self, do your trip reports at the end of the conference.

It’s been awhile since I’ve been at ESWC so it was nice to be back. The conference I think was down a bit in terms the number of attendees but the same community spirit and interesting content (check out the award winners) was there.  Shout out to Miriam Fernandez and the team for making it an invigorating event:

So what was I doing there. I was presenting work at the Deep Learning for Knowledge Graph workshop on trying to see if we could answer structured (e.g. SPARQL) queries over text (paper):

The workshop itself was packed. I think there were about 30-40 people in the room.  In addition to the presenting the workshop paper, I was also one of the mentors for the doctoral consortium. It was really nice to see the next up and coming students who put a lot of work into the session: a paper, a revised paper, a presentation and a poster. Victor and Maria-Esther did a fantastic job organizing this.

So what were my take-aways from the conference. I had many of the same thoughts coming out of this conference that I had when I was at the recent AKBC 2019 especially around the ideas of polyglot representation and scientific literature understanding as an important domain driver (e.g. a Predicting Entity Mentions in Scientific Literature and Mining Scholarly Data for Fine-Grained Knowledge Graph Construction. ) but there were some additional things as well.

Target Schemas

The first was a notion that I’ll term “target schemas”. Diana Maynard in her keynote talked about this. These are little conceptually focused ontologies designed specifically for the application domain. She talked about how working with domain experts to put together these little ontologies that could be the target for NLP tools was really a key part of building these domain specific analytical applications.   I think this notion of simple schemas is also readily apparent in many commercial knowledge graphs.

The notion of target schemas popped up again in an excellent talk by Katherine Thornton on the use of ShEx. In particular, I would call out the introduction of an EntitySchema part of Wikidata. (e.g. Schema for Human Gene or Software Title). These provide these little target schemas that say something to the effect of “Hey if you match this kind of schema, I can use them in my application”. I think this is a really powerful development.

The third keynote by Daniel Quercia was impressive. The Good City Life project about applying data to understand cities just makes you think. You really must check it out. More to this point of target schemas, however, was the use of these little conceptual descriptions in the various maps and analytics he did. By, for example, thinking about how to define urban sounds or feelings on a walking route, his team was able to develop these fantastic and useful views of the city.

I think the next step will be to automatically generate these target schemas. There was already some work headed into that direction. One was Generating Semantic Aspects for Queries , which was about how to use document mining to select which attributes for entities one should show for an entity. Think of it as selecting what should show up in a knowledge graph entity panel. Likewise, in the talk on Latent Relational Model for Relation Extraction, Gaetano Rossiello talked about how to think about using analogies between example entities to help extract these kind of schemas for small domains:

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I think this notion is worth exploring more.

Feral Spreadsheets

What more can I say:

We need more here. Things like MantisTable. Data wrangling is the problem. Talking to Daniel about the data behind his maps just confirmed this problem as well.

Knowledge Graph Engineering

This was a theme that was also at AKBC – the challenge of engineering knowledge graphs. As an example, the Knowledge Graph Building workshop was packed. I really enjoyed the discussion around how to evaluate the effectiveness of data mapping languages led by Ben de Meester especially with emphasis around developer usability. The experiences shared by the team from the industrial automation from Festo were really insightful. It’s amazing to see how knowledge graphs have been used to accelerate their product development process but also the engineering effort and challenges to get there.

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Likewise, Peter Haase in his audacious keynote (no slides – only a demo) showed how far we’ve come in the underlying platforms and technology to be able to create commercially useful knowledge graphs. This is really thanks to him and the other people who straddle the commercial/research line. It was neat to see the Open PHACTS style biomedical knowledge graph being built using SPARQL and api service wrappers:

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However, still these kinds of wrappers need to be built, the links need to be created and more importantly the data needs to be made available. A summary of challenges:

Overall, I really enjoyed the conference. I got a chance to spend sometime with a bunch of members of the community and it’s exciting to see the continued excitement and the number of new research questions.

Random Notes

 

Trip Report: AKBC 2019

June 2, 2019
academia, trip report
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About two weeks ago, I had the pleasure of attending the 1st Conference on Automated Knowledge Base Construction held in Amherst, Massachusetts. This conference follows up on a number of successful workshops held at venues like NeurIPS and NAACL. Why a conference and not another workshop? The general chair and host of the conference (and he really did feel like a host), Andrew McCallum articulated this as coming from three drivers: 1) the community spans a number of different research areas but was getting its own identity; 2) the workshop was outgrowing typical colocation opportunities and 3) the motivation to have a smaller event where people could really connect in comparison to some larger venues.

I don’t know the exact total but I think there was just over 110 people at the conference. Importantly, there were top people in the field and they stuck around and hung out. The size, the location, the social events (a lovely group walk in the forest in MA), all made it so that the conference achieved the goal of having time to converse in depth. It reminded me a lot of our Provenance Week events in the scale and depth of conversation.

Oh and Amherst is a terribly cute college town:

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Given that the conference subject is really central to my research, I found it hard to boil down everything into a some themes but I’ll give it a shot:

  • Representational polyglotism
  • So many datasets so little time
  • The challenges of knowledge (graph) engineering
  • There’s lots more to do!

Representational polyglotism

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One of the main points that came up frequently both in talks and in conversation was around what one should use as representation language for knowledge bases and for what purpose. Typed graphs have clearly shown their worth over the last 10 years but with the rise of knowledge graphs in a wide variety of industries and applications. The power of the relational approach especially in its probabilistic form  was shown in excellent talks by Lise Getoor on PSL and by Guy van den Broeck. For efficient query answering and efficiency in data usage, symbolic solutions work well. On the other hand, the softness of embedding or even straight textual representations enables the kind of fuzziness that’s inherent in human knowledge. Currently, our approach to unify these two views is often to encode the relational representation in an embedding space, reason about it geometrically, and then through it back over the wall into symbolic/relational space.  This was something that came up frequently and Van den Broek took this head on in his talk.

Then there’s McCallum’s notion of text as a knowledge graph. This approach was used frequently to different degrees, which is to be expected given that much of the contents of KGs is provided through information extraction. In her talk, Laura Dietz, discussed her work where she annotated the edges of a knowledge graph with paragraph text to improve entity ranking in search.  Likewise, the work presented by Yejin Choi around common sense reasoning used natural language as the representational “formalism”. She discussed the ATOMIC (paper) knowledge graph  which represents a crowed sourced common sense knowledge as natural language text triples (e.g. PersonX finds ___ in the literature).  She then described transformer based, BERT-esque, architectures  (COMET: Commonsense Transformers for Knowledge Graph Construction) that perform well on common sense reasoning tasks based on these kinds of representations.

The performance of BERT style language models on all sorts of tasks, led to Sebastian Riedel considering whether one should treat these models as the KB:

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It turns out that out-of-the box BERT performs pretty well as a knowledge base for single tokens that have been seen frequently by the model. That’s pretty amazing. Is storing all our knowledge in the parameters of a model the way to go? Maybe not but surely it’s good to investigate the extent of the possibilities here. I guess I came away from the event thinking that we are moving toward an environment where KBs will maintain heterogenous representations and that we are at a point where we need to embrace this range of representations to produce results in order face the challenges of the fuzzy. For example, the challenge of reasoning:

or of disagreement around knowledge as discussed by Chris Welty:

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So many datasets so little time

Progress in this field is driven by data and there were a lot of new datasets presented at the conference. Here’s my (probably incomplete) list:

  • OPIEC – from the makers of the MINIE open ie system – 300 million open information extracted triples with a bunch of interesting annotations;
  • TREC CAR dataset – cool task, auto generate articles for a search query;
  • HAnDS – a new dataset for fined grained entity typing  to support thousands of types;
  • HellaSwag – a new dataset for common sense inference designed to be hard for state-of-the-art transformer based architectures (BERT);
  • ShARC – conversational question answering dataset focused on follow-up questions
  • Materials Synthesis annotated data for extraction of material synthesis recipes from text. Look up in their GitHub repo for more interesting stuff
  • MedMentions – annotated corpora of UMLs mentions in biomedical papers from CZI
  • A bunch of datasets that were submitted to EMNLP so expect those to come soon – follow @nlpmattg.

The challenges of knowledge (graph) engineering

Juan Sequeda has been on this topic for a while – large scale knowledge graphs are really difficult to engineer. The team at DiffBot – who were at the conference – are doing a great job of supplying this engineering as a service through their knowledge graph API.  I’ve been working with another start-up SeMI who are also trying to tackle this challenge. But this is still complicated task as underlined for me when talking to Francois Scharffe who organized the recent industry focused Knowledge Graph Conference. The complexity of KG (social-technical) engineering was one of the main themes of that conference. An example of the need to tackle this complexity at AKBC was the work presented about the knowledge engineering going on for the KG behind Apple’s Siri. Xiao Ling emphasized that they spent a lot of their time thinking about and implementing systems for knowledge base construction developer workflow:

Thinking about these sorts of challenges was also behind several of the presentations in  the Open Knowledge Network workshop: Vicki Tardif from the Google Knowledge Graph discussed these issues in particular with reference to the muddiness of knowledge representation (e.g. how to interpret facets of a single entity? or how to align the inconsistencies of people with that of machines?). Jim McCusker and Deborah McGuinness’ work on the provenance/nanopublication driven WhyIs framework for knowledge graph construction is an important in that their software views a knowledge graph not as an output but as a set of tooling for engineering that graph.

The best paper of the conference Alexandria: Unsupervised High-Precision Knowledge Base Construction using a Probabilistic Program was also about how to lower the barrier to defining knowledge base construction steps using a simple probabilistic program. Building a KB from a single seed fact is impressive but then you need the engineering effort to massively scale probabilistic inference.

Alexandra Meliou’s work on using provenance to help diagnose these pipelines was particularly relevant to this issue. I have now added a bunch of her papers to the queue.

There’s lots more to do

One of the things I most appreciated was that many speakers had a set of research challenges at the end of their presentations. So here’s a set of things you could work on in this space curated from the event. Note these may be paraphrased.

  • Laura Dietz:
    • General purpose schema with many types
    • High coverage/recall (40%?)
    • Extraction of complex relations (not just triples + coref)
    • Bridging existing KGs with text
    • Relevant information extraction
    • Query-specific knowledge graphs
  • Fernando Pereira
    • combing source correlation and grounding
  • Guy van den Broeck
    • Do more than link predication
    • Tear down the wall between query evaluation and knowledge base completion
    • The open world assumption – take it seriously
  • Waleed Ammar
    • Bridge sentence level and document level predictions
    • Summarize published results on a given problem
    • Develop tools to facilitate peer review
    • How do we crowd source annotations for a specialized domain
    • What are leading indicators of a papers impact?
  • Sebastian Riedel
    • Determine what BERT actually knows or what it’s guessing
  • Xian Ren
    • Where can we source complex rules that help AKBC?
    • How do we induce transferrable latent structures from pre-trained models?
    • Can we have modular neural networks for modeling compositional rules?
    • Ho do we model “human effort” in the objective function during training?
  • Matt Gardner
    • Make hard reading datasets by baking required reasoning into them

Finally, I think the biggest challenge that was laid down was from Claudia Wagner, which is how to think a bit more introspectively about the theory behind our AKBC methods and how we might even bring the rigor of social science methodology to our technical approaches:

I left AKBC 2019 with a fountain of ideas and research questions, which I count as a success. This is a community to watch.  AKBC 2020 is definitely on my list of events to attend next year.

Random Pointers

 

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