About modelling styles in ontologies

As any modeller will know, there are pieces of information or knowledge that can be represented in different ways. For instance, representing ‘marriage’ as class or as a ‘married to’ relationship, adding ‘address’ as an attribute or a class in one’s model, and whether ‘employee’ will be positioned as a subclass of ‘person’ or as a role that ‘person’ plays. In some cases, there a good ontological arguments to represent it in one way or the other, in other cases, that’s less clear, and in yet other cases, efficiency is king so that the most compact way of representing it is favoured. This leads to different design decisions in ontologies, which hampers ontology reuse and alignment and affects other tasks, such as evaluating competency questions over the ontology and verbalising ontologies.

When such choices are made consistently throughout the ontology, one may consider this to be a modelling style or representation style. If one then knows which style an ontology is in, it would simplify use and reuse of the ontology. But what exactly is a representation style?

While examples are easy to come by, shedding light on that intuitive notion turned out to be harder than it looked like. My co-author Pablo Fillottrani and I tried to disentangle it nonetheless, by characterising the inherent features and the dimensions by which a style may differ. This resulted in 28 different traits for the 10 identified dimensions.  For instance, the dimension “modular vs. monolithic” has three possible options: 1) ‘Monolithic’, where the ontology is stored in one file (no imports or mergers); 2) ‘Modular, external’, where at least one ontology is imported or merged, and it kept its URI (e.g., importing DOLCE into one’s domain ontology, not re-creating it there); 3) ‘Modular, internal’, where there’s at least one ontology import that’s based on having carved up the domain in the sense of decomposition of the domain (e.g., dividing up a domain into pizzas and drinks at pizzerias).  Other dimensions include, among others, the granularity of relations (many of few), how the hierarchy looks like, and attributes/data properties.

We tried to “eat our own dogfood” and applied the dimensions and traits to a set of 30 ontologies. This showed that it is feasible to do, although we needed two rounds to get to that stage—after the first round of parallel annotation, it turned out we had interpreted a few traits differently, and needed to refine the number of traits and be more precise in their descriptions (which we did). Perhaps unsurprising, some tendencies were observed, and we could identify three easily recognisable types of ontologies because most ontologies had clearly one or the other trait and similar values for sets of trait. Of course, there were also ontologies that were inherently “mixed” in the sense of having applied different and conflicting design decisions within the same ontology, or even included two choices. Coding up the results, we generated two spider diagrams that visualise that difference. Here’s one:

Details of the dimensions, traits, set-up and results of the evaluation, and discussion thereof have been published this week [1] and we’ll present it next month at the 1st Iberoamerican Conference on Knowledge Graphs and Semantic Web (KGSWC’19), in Villa Clara, Cuba, alongside 13 other papers on ontologies. I’m looking forward to it!

 

References

[1] Keet, C.M., Fillottrani, P.R.. Dimensions Affecting Representation Styles in Ontologies. 1st Iberoamerican conference on Knowledge Graphs and Semantic Web (KGSWC’19). Springer CCIS vol 1029, 186-200. 24-28 June 2019, Villa Clara, Cuba. Paper at Springer

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Some experiences on making a textbook available

I did make available a textbook on ontology engineering for free in July 2018. Meanwhile, I’ve had several “why did you do this and not a proper publisher??!?” I had tried to answer that already in the textbook’s FAQ. Turns out that that short answer may be a bit too short after all. So, here follows a bit more about that.

The main question I tried to answer in the book’s FAQ was “Would it not have been better with a ‘proper publisher’?” and the answer to that was:

Probably. The layout would have looked better, for sure. There are several reasons why it isn’t. First and foremost, I think knowledge should be free, open, and shared. I also have benefited from material that has been made openly available, and I think it is fair to continue contributing to such sharing. Also, my current employer pays me sufficient to live from and I don’t think it would sell thousands of copies (needed for making a decent amount of money from a textbook), so setting up such a barrier of high costs for its use does not seem like a good idea. A minor consideration is that it would have taken much more time to publish, both due to the logistics and the additional reviewing (previous multi-author general textbook efforts led to nothing due to conflicting interests and lack of time, so I unlikely would ever satisfy all reviewers, if they would get around reading it), yet I need the book for the next OE installment I will teach soon.

Ontology Engineering (OE) is listed as an elective in the ACM curriculum guidelines. Yet, it’s suited best for advanced undergrad/postgrad level because of the prerequisites (like knowing the basics of databases and conceptual modeling). This means there won’t be big 800-students size classes all over the world lining up for OE. I guess it would not go beyond some 500-1000/year throughout the world (50 classes of 10-20 computer science students), and surely not all classes would use the textbook. Let’s say, optimistically, that 100 students/year would be asked to use the book.

With that low volume in mind, I did look up the cost of similar books in the same and similar fields with the ‘regular’ academic publishers. It doesn’t look enticing for either the author or the student. For instance this one from Springer and that one from IGI Global are all still >100 euro. for. the. eBook., and they’re the cheap ones (not counting the 100-page ‘silver bullet’ book). Handbooks and similar on ontologies, e.g., this and that one are offered for >200 euro (eBook). Admitted there’s the odd topical book that’s cheaper and in the 50-70 euro range here and there (still just the eBook) or again >100 as well, for a, to me, inexplicable reason (not page numbers) for other books (like these and those). There’s an option to publish a textbook with Springer in open access format, but that would cost me a lot of money, and UCT only has a fund for OA journal papers, not books (nor for conference papers, btw).

IOS press does not fare much better. For instance, a softcover version in the studies on semantic web series, which is their cheapest range, would be about 70 euro due to number of pages, which is over R1100, and so again above budget for most students in South Africa, where the going rate is that a book would need to be below about R600 for students to buy it. A plain eBook or softcover IOS Press not in that series goes for about 100 euro again, i.e., around R1700 depending on the exchange rate—about three times the maximum acceptable price for a textbook.

The MIT press BFO eBook is only R425 on takealot, yet considering other MIT press textbooks there, with the size of the OE book, it then would be around the R600-700. Oxford University Press and its Cambridge counterpart—that, unlike MIT press, I had checked out when deciding—are more expensive and again approaching 80-100 euro.

One that made me digress for a bit of exploration was Macmillan HE, which had an “Ada Lovelace day 2018” listing books by female authors, but a logics for CS book was again at some 83 euros, although the softer area of knowledge management for information systems got a book down to 50 euros, and something more popular, like a book on linguistics published by its subsidiary “Red Globe Press”, was down to even ‘just’ 35 euros. Trying to understand it more, Macmillan HE’s “about us” revealed that “Macmillan International Higher Education is a division of Macmillan Education and part of the Springer Nature Group, publishers of Nature and Scientific American.” and it turns out Macmillan publishes through Red Globe Press. Or: it’s all the same company, with different profit margins, and mostly those profit margins are too high to result in affordable textbooks, whichever subsidiary construction is used.

So, I had given up on the ‘proper publisher route’ on financial grounds, given that:

  • Any ontology engineering (OE) book will not sell large amounts of copies, so it will be expensive due to relatively low sales volume and I still will not make a substantial amount from royalties anyway.
  • Most of the money spent when buying a textbook from an established publisher goes to the coffers of the publisher (production costs etc + about 30-40% pure profit [more info]). Also, scholarships ought not to be indirect subsidy schemes for large-profit-margin publishers.
  • Most publishers would charge an amount of money for the book that would render the book too expensive for my own students. It’s bad enough when that happens with other textbooks when there’s no alternative, but here I do have direct and easy-to-realise agency to avoid such a situation.

Of course, there’s still the ‘knowledge should be free’ etc. argument, but this was to show that even if one were not to have that viewpoint, it’s still not a smart move to publish the textbook with the well-known academic publishers, even more so if the topic isn’t in the core undergraduate computer science curriculum.

Interestingly, after ‘publishing’ it on my website and listing it on OpenUCT and the Open Textbook Archive—I’m certainly not the only one who had done a market analysis or has certain political convictions—one colleague pointed me to the non-profit College Publications that aims to “break the monopoly that commercial publishers have” and another colleague pointed me to UCT press. I had contacted both, and the former responded. In the meantime, the book has been published by CP and is now also listed on Amazon for just $18 (about 16 euro) or some R250 for the paperback version—whilst the original pdf file is still freely available—or: you pay for production costs of the paperback, which has a slightly nicer layout and the errata I knew of at the time have been corrected.

I have noticed that some people don’t take the informal self publishing seriously—even below the so-called ‘vanity publishers’ like Lulu—notwithstanding the archives to cater for it, the financial take on the matter, the knowledge sharing argument, and the ‘textbooks for development’ in emerging economies angle of it. So, I guess no brownie points from them then and, on top of that, my publication record did, and does, take a hit. Yet, writing a book, as an activity, is a nice and rewarding change from just churning out more and more papers like a paper production machine, and I hope it will contribute to keeping the OE research area alive and lead to better ontologies in ontology-driven information systems. The textbook got its first two citations already, the feedback is mostly very positive, readers have shared it elsewhere (reddit, ungule.it, Open Libra, Ebooks directory, and other platforms), and I recently got some funding from the DOT4D project to improve the resources further (for things like another chapter, new exercises, some tools development to illuminate the theory, a proofreading contest, updating the slides for sharing, and such). So, overall, if I had to make the choice again now, I’d still do it again the way I did. Also, I hope more textbook authors will start seeing self-publishing, or else non-profit, as a good option. Last, the notion of open textbooks is gaining momentum, so you even could become a trendsetter and be fashionable 😉

FOIS’18 conference report

To some perhaps surprisingly, despite being local organizer, I could attend all sessions of the 10th International Conference Formal Ontology in Information Systems as participant (cf. running around for last-minute things). It just wasn’t as much of a trip as it usually is: only 15 minutes to town at the Atlantic Imbizo conference venue, which is situated between the Clock Tower and (award-winning) Zeitz MOCAA at Cape Town’s V&A Waterfront. This blog post has turned into a longer post than intended—yet, there’s still so much left out to talk about—and it is divided up into sections on keynotes, presentations, ontologies, and the (ontologically inappropriate basket of) other things.

 

Keynotes

The first keynote was presented by (emeritus) professor in philosophy Peter Simons from Trinity College Dublin and Universität Salzburg, on the ontology of aboutness (slides).

Peter Simon during his keynote talk

That may sound a bit abstract, but it is not unusual for some information system that it will have to record statements about something, such as different medical opinions, changes of policies, plans or expectations, and we need a way to represent that and deal with it. Simons discussed several earlier proposals before proposing his own, which includes as main entities a bearer, act, time, act-type, mental content, mental content type, intentional objects, referent, and referent type (slide 16), and then variants for pictorial and linguistic (speech and writing). And, in closing, his advice of “Don’t get involved in irrelevant philosophical disputes”.

The second keynote was presented by Alessandro Oltramari, who works at Bosch Research and Technology Centre in Pittsburgh, USA. He presented several of Bosch’s projects where ontologies are used in one way or another (slides) and that he was involved in. One of them was about knowledge-based intelligent IoT and another on an emergency assistant, or, in business sales parlance, a “personal guardian angel” mobile device that has location awareness, safety information of those locations, a decision support system for alternate route computation, and automatic escalation. The ontologies used include the foundational ontology DOLCE, the domain ontology of semantic sensor networks (SSN) from the W3C, and specific schemas developed in-house. Another project on a knowledge-based chatbot for healthcare policies links up DOLCE, schema.org, and some in-house schemas with Highmark-specific information (and is not ashamed of using SKOS). Om my question what methods and methodologies were used for the in-house ontology development, the (disappointing) answer was, unfortunately, only “DOLCE and OntoClean”, but the former is neither a method nor a methodology (it implies a top-down approach), and the latter is some 15 years old, as if nothing has happened in ontology engineering in the meantime (more about that further below). Regardless, it was good to see that ontologies are being used in industry.

The third keynote (slides) was by Riichiro Mizoguchi from the Japan Advanced Institute of Science and Technology (JAIST), on a state-centric methodology, which I’ll leave for a separate post.

Riichiro Mizoguchi during his keynote talk.

 

Presentations

The report on the presentations easily could take up several pages, but I’ll try to keep it short, lest otherwise this post never gets posted. The first session of the conference was on foundations. This included Antony Galton’s assessment of the treatment of time in upper ontologies [1]. It was mildly entertaining in that it turned out that BFO would need abstract things for its treatment of time (which it doesn’t have and doesn’t like) and adheres to Newtonian physics cf. the latest scientific theories. It is definitely on my list of papers to read in more detail. Another paper-for-printing to read is Torsten Hahmann’s work on mereotopology, which extends it to multidimensional space [2]. A nice bonus (though it ought not to be perceived as such) is that at least the theorems in the paper have been proved with Prover9 and Vampire (cf. having to double-check them manually). Laure Vieu presented a proposal for a graph-based approach to represent structure among the components of an entity [3], which is apparently different from the graph-based approach for representing molecules (within the Semantic Web context); I’ll have to look at that in more detail, for it sounds like it might be of some use for the parts aspects of part-whole relations.

Besides such theoretical contributions that are rather distant from applications, there were two of note that were motivated from praxis more clearly. One was about the ontological foundations of competition and the sort of competitive relations there are [4], which was presented by Tiago Prince Sales. The other one was presented by Pawel Garbacz, whose presentation conveyed more than the paper so as to get a real feel of the problem, being identity criteria for localities [5], with complicating use cases extracted from a Polish history project. He presented some examples of changes and a proposal for how to identify a locality/settlement. For instance, settlements can get moved altogether, have a population-only move, split into two, be merged, renamed and renamed again, deserted by a population and repopulated and renamed, and so on. When is it the same settlement and when is it another one? The paper [5] describes a first solution for identity criteria with an event-based approach to identity of localities.

My presentation on part-whole relations in Zulu language and culture [6] was scheduled in the ‘applications’ session, which had positive feedback and some pointers that may assist with future work.

 

venue during a Q&A session

Ontologies

Besides presentations, there was a discussion session on “what constitutes a good ontology paper?” for the Applied Ontology journal. Seeing the ontology papers at FOIS now, they should have done such as session for FOIS as well. There are four papers in the proceedings describing OWL files: “Amnestic forgery” (AF, conceptual metaphors) [7] presented by Mehwish Alam, UNiCS for research and innovation policy [8] presented by Fernando Roda, SAREF4Health [9] presented by João Moreira, and religious and spiritual belief (ORSB) [10] presented by Stefan Schulz. Skimming through each paper, AF, UNiCS and ORSB do not use a methodology explicitly, none of them uses existing methods, but they all do use a foundational or top-level ontology or the WordNet material, and then it’s cool enough to get into FOIS, apparently. This is a bit disappointing. At least SAREF4Health presented a set of competency questions, a systematic approach and broader framework, and some evaluation, and ORSB reuses not only top-level and top-domain ontologies but also tests some patterns. AF and ORSB have some interest to it as they’re addressing relatively novel modeling issues to solve and the ORSB discussion could be used more broadly for any “terms of dubious reference”. UNiCS is not really an ontology but an information model or, at best, a conceptual data model (e.g. calling “SCOPUS subject” an ontology is pushing it a bit too far); it makes their OBDA scenario easier to realize, true, but that’s a separate discussion. Fig 1 of SAREF4Health doesn’t look any better either, which has all the hallmarks of a plain UML Class Diagram (attributes with data types and such), with object diagram components attached and coloured in and annotated with OntoUML. SAREF4Health’s other downsides are things like “implementing the ontology as RDF” that just hurts to read (it is left implicit for AF that is plugged into the LOD cloud), as is the download in Turtle format (cf. the required exchange syntax of OWL 2), which isn’t even available at the provided link when you click on it (copy-paste gets you in the right direction), but is [I think] in some github sub-directory that has a whole bunch of ttl files with neither head nor tail, but one of them is called saref4health.ttl. On first inspection, it has plenty of data properties and data type use, and the class-as-instance issue here and there (e.g., ‘Rechargeable Lithium Polymer battery’ as instance cf. class), and others (e.g., a ‘series’ of measurements is not a subclass of a measurement) and very many classes directly subsumed by top, though some are knock-on effects from imports.

And then ontologists at FOIS deplored that there are many domain ontologies that are of poor quality and artifacts presented as ontologies but aren’t. The FOIS reviewers themselves apparently can’t even get their act together in the reviewing process, where artifacts that are sold as domain ontologies but aren’t (UNiCS, SAREF4Health) make it not only through the reviewing process but, moreover, even get a best paper award from the PC chairs (SAREF4Health). The PC chairs wanted to make a political statement to communicate that FOIS accepts domain ontology papers. It is good that the FOIS topics are becoming less narrow and I’m not saying they are pointless papers or lousy artifacts per sé—they are useful reference papers and UNiCS and SAREF4Health perform the application tasks they’re supposed to be performing, which is a good thing. Maybe, collectively, ontology developers can’t do better or don’t need to do better w.r.t. applied ontology? Either way, once upon a time there were principles for what ontologies are; what happened to that? Also, there are multiple methodologies for domain ontology development, and there are a myriad of methods and tools, which have been mostly ignored. For instance, using one foundational ontology over another ‘just because I know x’ is neither a scientific nor a sound engineering approach. There are comparisons, requirements, and a mix of the two to help you figure out which one is the best to use; an early tool for that is ONSET, the ONtology Selection and Explanation Tool, developed by Zubeida Khan (more data). To name one example.

Coincidentally, ontology engineering papers with such a content do not, or very rarely, make it into FOIS; but just that they don’t (because they’re typically not philosophical enough), doesn’t mean they don’t exist. Just in case a FOIS ontologist would like to explore methods, methodologies and tools for ontology development: ESWC, EKAW, and K-CAP are good/top conferences covering such topics in whole or in part, and Chapter 5 of the ontology engineering textbook provides a sampling as well (as do some other sections in Block II). Considering my critical comments, one may ask whether my ontologies and ontology papers are any better, or anyone else’s for that matter. Perhaps, perhaps not. You can check for yourself some of my recent papers on domain ontologies that also have OWL files[1] that I was involved in developing; one paper was intended as a reference paper for the domain ontology [11], another paper was a bit of both domain ontology and some framework [12], and yet another turned into a core ontology [13] (v1, with the main categories; there’s an updated version for the relations).

Anyway, returning to the first sentence of this section: the open forum discussion did not make it any clearer as to what would be the characteristics of a good ontology paper for the Applied Ontology journal (or FOIS, for that matter). Mainly just Protégé screenshots certainly is not, but opinions varied as to what would be. Going by examples of the ontology papers that made it through: use of a top-level or foundational ontology and some modeling issues and solutions seems to be preferred, evaluation and usage & uptake as a nice-to-have. Is developing an (domain) ontology science? That question wasn’t answered unanimously; I think it was leaning towards a ‘mostly no’ w.r.t. applied ontology but it may be if it’s the first to solve a modeling issue. How to evaluate the ontology? Another question without a satisfactory answer. Overall, the criteria for an ontology paper—let alone for the ontology itself—are “TBD” and meanwhile one has to hope that one will get a supportive ‘reviewer 2’.

 

Other

In case you have clicked-though to one or more of the listed papers, you may have noticed that the FOIS’18 proceedings are Open Access—paid for by those who registered for the conference (it was calculated in the registration fee). I suppose the next FOIS organisers and the IAOA exec may like your opinion on that approach.

mentors of the early career symposium papers

Besides the best paper award for SAREF4Health [9], there were two “distinguished paper awards”, which went to aforementioned paper on the graph-based approach for structured universals by Laure Vieu and Claudio Masolo [3] and to the foundational ontologies for units of measure by Michael Grüninger and co-authors [14]. The early career symposium went well and from hearsay they had a good social activity, too. There were lots of interesting conversations, networking, good food, and so on, and lots more to write about. There are also more photos.

Some of the postgraduate students and a recent PhD graduate in the spotlight at the closing ceremony, being thanked for chairing the sessions.

Last, but not least: the next FOIS in 2020 will be in Bolzano, Italy, as part of a ‘Bolzano summer of knowledge’ with more co-located conferences, workshops, and summer schools.

 

References

[1] Antony Galton. The treatment of time in upper ontologies. Proc. of FOIS’18. IOS Press, 306: 33-46.

[2] Thorsten Hahmann. On Decomposition Operations in a Theory of Multidimensional Qualitative Space. Proc. of FOIS’18. IOS Press, 306: 173-186.

[3] Claudio Masolo, Laure Vieu. Graph-Based Approaches to Structural Universals and Complex States of Affairs. Proc. of FOIS’18. IOS Press, 306: 69-82.

[4] Tiago Prince Sales, Daniele Porello, Nicola Guarino, Giancarlo Guizzardi, John Mylopoulos. Ontological Foundations of Competition. Proc. of FOIS’18. IOS Press, 306: 96-112.

[5] Pawel Garbacz, Agnieszka Ławrynowicz, Bogumił Szady. Identity criteria for localities. Proc. of FOIS’18. IOS Press, 306: 47-56.

[6] C. Maria Keet, Langa Khumalo. On the Ontology of Part-Whole Relations in Zulu Language and Culture. Proc. of FOIS’18. IOS Press, 306: 225-238.

[7] Aldo Gangemi, Mehwish Alam, Valentina Presutti. Amnestic Forgery: An Ontology of Conceptual Metaphors. Proc. of FOIS’18. IOS Press, 306: 159-172.

[8] Alessandro Mosca, Fernando Roda, Guillem Rull. UNiCS – The Ontology for Research and Innovation Policy Making. Proc. of FOIS’18. IOS Press, 306: 200-210.

[9] João Moreira, Luís Ferreira Pires, Marten van Sinderen, Laura Daniele. SAREF4health: IoT Standard-Based Ontology-Driven Healthcare Systems. Proc. of FOIS’18. IOS Press, 306: 239-252.

[10] Stefan Schulz, Ludger Jansen. Towards an Ontology of Religious and Spiritual Belief. Proc. of FOIS’18. IOS Press, 306: 253-260.

[11] Keet, C.M., Lawrynowicz, A., d’Amato, C., Kalousis, A., Nguyen, P., Palma, R., Stevens, R., Hilario, M. The Data Mining OPtimization ontology. Web Semantics: Science, Services and Agents on the World Wide Web, 2015, 32:43-53.

[12] Chavula, C., Keet, C.M. An Orchestration Framework for Linguistic Task Ontologies. 9th Metadata and Semantics Research Conference (MTSR’15), Garoufallou, E. et al. (Eds.). Springer CCIS vol. 544, 3-14.

[13] Keet, C.M. A core ontology of macroscopic stuff. 19th International Conference on Knowledge Engineering and Knowledge Management (EKAW’14). K. Janowicz et al. (Eds.). 24-28 Nov, 2014, Linkoping, Sweden. Springer LNAI vol. 8876, 209-224.

[14] Michael Grüninger, Bahar Aameri, Carmen Chui, Torsten Hahmann, Yi Ru. Foundational Ontologies for Units of Measure. Proc. of FOIS’18. IOS Press, 306: 211-224.

[1] I have others developed as part of methods & tools research

ISAO 2018, Cape Town, ‘trip’ report

The Fourth Interdisciplinary School on Applied Ontology has just come to an end, after five days of lectures, mini-projects, a poster session, exercises, and social activities spread over six days from 10 to 15 September in Cape Town on the UCT campus. It’s not exactly fair to call this a ‘trip report’, as I was the local organizer and one of the lecturers, but it’s a brief recap ‘trip report kind of blog post’ nonetheless.

The scientific programme consisted of lectures and tutorials on:

The linked slides (titles of the lectures, above) reveal only part of the contents covered, though. There were useful group exercises and plenary discussion with the ontological analysis of medical terms such as what a headache is, a tooth extraction, blood, or aspirin, an exercises on putting into practice the design process of a conceptual modelling language of one’s liking (e.g.: how to formalize flowcharts, including an ontological analysis of what those elements are and ontological commitments embedded in a language), and trying to prove some theorems of parthood theories.

There was also a session with 2-minute ‘blitztalks’ by participants interested in briefly describing their ongoing research, which was followed by an interactive poster session.

It was the first time that an ISAO had mini-projects, which turned out to have had better outcomes than I expected, considering the limited time available for it. Each group had to pick a term and investigate what it meant in the various disciplines (task description); e.g.: what does ‘concept’ or ‘category’ mean in psychology, ontology, data science, and linguistics, and ‘function’ in manufacturing, society, medicine, and anatomy? The presentations at the end of the week by each group were interesting and most of the material presented there easily could be added to the IAOA Education wiki’s term list (an activity in progress).

What was not a first-time activity, was the Ontology Pub Quiz, which is a bit of a merger of scientific programme and social activity. We created a new version based on questions from several ISAO’18 lecturers and a few relevant questions created earlier (questions and answers; we did only questions 1-3,6-7). We tried a new format compared to the ISAO’16 quiz and JOWO’17 quiz: each team had 5 minutes to answer a set of 5 questions, and another team marked the answers. This set-up was not as hectic as the other format, and resulted in more within-team interaction cf. among all participants interaction. As in prior editions, some questions and answers were debatable (and there’s still the plan to make note of that and fix it—or you could write an article about it, perhaps :)). The students of the winning team received 2 years free IAOA membership (and chocolate for all team members) and the students of the other two teams received one year free IAOA membership.

Impression of part of the poster session area, moving into the welcome reception

As with the three previous ISAO editions, there was also a social programme, which aimed to facilitate getting to know one another, networking, and have time for scientific conversations. On the first day, the poster session eased into a welcome reception (after a brief wine lapse in the coffee break before the blitztalks). The second day had an activity to stretch the legs after the lectures and before the mini-project work, which was a Bachata dance lesson by Angus Prince from Evolution Dance. Not everyone was eager at the start, but it turned out an enjoyable and entertaining hour. Wednesday was supposed to be a hike up the iconic Table Mountain, but of all the dry days we’ve had here in Cape Town, on that day it was cloudy and rainy, so an alternative plan of indoor chocolate tasting in the Biscuit Mill was devised and executed. Thursday evening was an evening off (from scheduled activities, at least), and Friday early evening we had the pub quiz in the UCT club (the campus pub). Although there was no official planning for Saturday afternoon after the morning lectures, there was again an attempt at Table Mountain, concluding the week.

The participants came from all over the world, including relatively many from Southern Africa with participants coming also from Botswana and Mauritius, besides several universities in South Africa (UCT, SUN, CUT). I hope everyone has learned something from the programme that is or will be of use, enjoyed the social programme, and made some useful new contacts and/or solidified existing ones. I look forward to seeing you all at the next ISAO or, better, FOIS, in 2020 in Bolzano, Italy.

Finally, as a non-trip-report comment from my local chairing viewpoint: special thanks go to the volunteers Zubeida Khan for the ISAO website, Zola Mahlaza and Michael Harrison for on-site assistance, and Sam Chetty for the IT admin.

From ontology verbalisation to language learning exercises

I’m aware that to most people ‘playing with’ (investigating) ontologies and isiZulu does not sound particularly useful on the face of it. Yet, there’s the some long-term future music, like eventually being able to generate patient discharge notes in one’s own language, which will do its bit to ameliorate the language barrier in healthcare in South Africa so that patients at least will adhere to the treatment instructions a little better, and therewith receive better quality healthcare. But benefits in the short-term might serve something as well. To that end, I proposed an honours project last year, which has been completed in the meantime, and one of the two interesting outcomes has made it into a publication already [1]. As you may have guessed from the title, it’s about automation for language learning exercises. The results will be presented at the 6th Workshop on Controlled Natural Language, in Maynooth, Ireland in about 2 weeks time (27-28 August). In the remainder of this post, I highlight the main contributions described in the paper.

First, regarding the post’s title, one might wonder what ontology verbalisation has to do with language learning. Nothing, really, except that we could reuse the algorithms from the controlled natural language (CNL) for ontology verbalisation to generate (computer-assisted) language learning exercises whose answers can be computed and marked automatically. That is, the original design of the CNL for things like pluralising nouns, verb conjugation, and negation that is used for verbalising ontologies in isiZulu in theory [2] and in practice [3], was such that the sentence generator is a detachable module that could be plugged in elsewhere for another task that needs such operations.

Practically, the student who designed and developed the back-end, Nikhil Gilbert, preferred Java over Python, so he converted most parts into Java, and added a bit more, notably the ‘singulariser’, a sentence scrabble, and a sentence generator. Regarding the sentence generator, this is used as part of the exercises & answers generator. For instance, we know that humans and the roles they play (father, aunt, doctor, etc.) are mostly in isiZulu’s noun classes 1, 2, 1a, 2a, or 3a, that those classes do not (or rarely?) have non-human nouns and generally it holds for all humans and their roles that they can ‘eat’, ‘talk’ etc. This makes it relatively easy create a noun chain and a verb chain list to mix and match nouns with verbs accordingly (hurrah! for the semantics-based noun class system). Then, with the 231 nouns and 59 verbs in the newly constructed mini-corpus, the noun chain and the verb chain, 39501 unique question sentences could be generated, using the following overall architecture of the system:

Architecture of the CNL-driven CALL system. The arrows indicate which upper layer components make use of the lower layer components. (Source: [1])

From a CNL perspective as well as the language learning perspective, the actual templates for the exercises may be of interest. For instance, when a learner is learning about pluralising nouns and their associated verb, the system uses the following two templates for the questions and answers:

Q: <prefixSG+stem> <SGSC+VerbRoot+FV>
A: <prefixPL+stem> <PLSC+VerbRoot+FV>
Q: <prefixSG+stem> <SGSC+VerbRoot+FV> <prefixSG+stem>
A: <prefixPL+stem> <PLSC+VerbRoot+FV> <prefixPL+stem>

The answers can be generated automatically with the algorithms that generate the plural noun (from ‘prefixSG’ to ‘prefixPL’) and add the plural subject concord (from ‘SGSC’ to ‘PLSC’, in agreement with ‘prefixPL’), which were developed as part of the GeNI project on ontology verbalization. This can then be checked against what the learner has typed. For instance, a generated question could be umfowethu usula inkomishi and the correct answer generated (to check the learner’s response against) is abafowethu basula izinkomishi. Another example is generation of the negation from the positive, or, vv.; e.g.:

Q: <PLSC+VerbRoot+FV>
A: <PLNEGSC+VerbRoot+NEGFV>

For instance, the question may present batotoba and the correct answer is then abatotobi. In total, there are six different types of sentences, with two double, like the plural above, hence a total of 16 templates. It is not a lot, but it turned out it is one of the very few attempts to use a CNL in such way: there is one paper that also will be presented at CNL’18 in the same session [4], and an earlier one [5] uses a fancy grammar system (that we don’t have yet computationally for isiZulu). This is not to be misunderstood as that this is one of the first CNL/NLG-based system for computer-assisted language learning—e.g., there’s assistance in essay writing, grammar concept question generation, reading understanding question generation—but curiously very little on CNLs or NLG for the standard entry-level type of questions to learn the grammar. Perhaps the latter is considered ‘boring’ for English by now, given all the resources. However, thousands of students take introduction courses in isiZulu each year, and some automation can alleviate the pressure of routine activities from the lecturers. We have done some evaluations with learners—with encouraging results—and plan to do some more, so that it may eventually transition to actual use in the courses; that is: TBC…

 

References

[1] Gilbert, N., Keet, C.M. Automating question generation and marking of language learning exercises for isiZulu. 6th International Workshop on Controlled Natural language (CNL’18). IOS Press. Co. Kildare, Ireland, 27-28 August 2018. (in print)

[2] Keet, C.M., Khumalo, L. Toward a knowledge-to-text controlled natural language of isiZulu. Language Resources and Evaluation, 2017, 51(1): 131-157.

[3] Keet, C.M. Xakaza, M., Khumalo, L. Verbalising OWL ontologies in isiZulu with Python. The Semantic Web: ESWC 2017 Satellite Events, Blomqvist, E. et al. (eds.). Springer LNCS vol. 10577, 59-64.

[4] Lange, H., Ljunglof, P. Putting control into language learning. 6th International Workshop on Controlled Natural language (CNL’18). IOS Press. Co. Kildare, Ireland, 27-28 August 2018. (in print)

[5] Gardent, C., Perez-Beltrachini, L. Using FB-LTAG Derivation Trees to Generate Transformation-Based Grammar Exercises. Proc. of TAG+11, Sep 2012, Paris, France. pp117-125, 2012.

An Ontology Engineering textbook

My first textbook “An Introduction to Ontology Engineering” (pdf) is just released as an open textbook. I have revised, updated, and extended my earlier lecture notes on ontology engineering, amounting to about 1/3 more new content cf. its predecessor. Its main aim is to provide an introductory overview of ontology engineering and its secondary aim is to provide hands-on experience in ontology development that illustrate the theory.

The contents and narrative is aimed at advanced undergraduate and postgraduate level in computing (e.g., as a semester-long course), and the book is structured accordingly. After an introductory chapter, there are three blocks:

  • Logic foundations for ontologies: languages (FOL, DLs, OWL species) and automated reasoning (principles and the basics of tableau);
  • Developing good ontologies with methods and methodologies, the top-down approach with foundational ontologies, and the bottom-up approach to extract as much useful content as possible from legacy material;
  • Advanced topics that has a selection of sub-topics: Ontology-Based Data Access, interactions between ontologies and natural languages, and advanced modelling with additional language features (fuzzy and temporal).

Each chapter has several review questions and exercises to explore one or more aspects of the theory, as well as descriptions of two assignments that require using several sub-topics at once. More information is available on the textbook’s page [also here] (including the links to the ontologies used in the exercises), or you can click here for the pdf (7MB).

Feedback is welcome, of course. Also, if you happen to use it in whole or in part for your course, I’d be grateful if you would let me know. Finally, if this textbook will be used half (or even a quarter) as much as the 2009/2010 blogposts have been visited (around 10K unique visitors since posting them), that would mean there are a lot of people learning about ontology engineering and then I’ll have achieved more than I hoped for.

UPDATE: meanwhile, it has been added to several open (text)book repositories, such as OpenUCT and the Open Textbook Archive, and it has been featured on unglue.it in the week of 13-8 (out of its 14K free ebooks).

Ontology pub quiz questions of ISAO 2016 and JOWO 2017

In 2016 when I was a PC chair of the International School for Applied Ontology (ISAO 2016), the idea of organising a contest for the participants turned into a pub quiz somehow. The lecturers provided one or more questions on the topics they’d be teaching and I added a few as well. This set of ISAO16 ontology pub quiz questions is now finally online. It comes with the warning that it is biased toward the topics covered at ISAO 2016, and it turned out that there were a few questions not well formulated and/or not everyone agreed with the answer.

Notwithstanding, it was deemed sufficiently ok as idea in that the general chair of the Joint Ontology Workshops (JOWO 2017) wanted one for JOWO 2017 as well. Several questions were thrown out of the ISAO16 set for various reasons and more general Ontology questions made their way in, as well as a few ‘fun’ and trivia ones in the hope to add some more entertainment to the ontology pub quiz. The JOWO17 pub quiz question set with answers is now also online to play with, which, in my opinion, is a nicer set than the ISAO16 one. Here are a few questions to give you a taste of it:

  • Where/when can a pointless theory be relevant?
  • What is the goal of guerrilla ontology?
  • No Italian pizza has fruit as topping. Which of the following is (an)/are Italian pizza(s)? Pizza Hawaii, Pizza margherita, Pizza bianca romana (‘white roman pizza’)
  • When was the earliest published occurrence of the word “ontology”?

It turned out that it still was not entirely free of debate. If you disagree with one of the answers now, then let me paraphrase Stefano Borgo, who co-ran the JOWO17 pub quiz at the Irish pub in Bolzano on 23 September: maybe there’s something there to write up and submit a paper to FOIS 2018 :-). Or you can write it in the blog post comments section below, so that those questions will/should not be recycled and I can add longer answers to the questions.