Rezk PhD.

Researcher & Data Scientist


About Me

I am currently an ontologist at Google working on different aspects of Google Knowledge Graph such as formal reasoning, information extraction and schema matching (ML based). Previously, I worked as a data scientist at Rakuten and working mainly on market segmentation, semantic information extraction, and profiling for the finance sector. While working in the academia, my research interests were in the areas of (but not limited to) Ontology Based Data Access (OBDA) for data integration, query optimization, Knowledge Representation and Reasoning (KRR) and Natural Language Processing.
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My Skills

Semantic Web 90%
Machine Learning 85%
Python 90%
C++ 80%
Data Bases 80%
NLP 85%
Java 80%

Rakuten Inc. (Japan)

15/12/2015 - 2/2/2019: Researcher and Data scientist.

F.U.B. (Italy)

1/5/2013-1/12/2015: Post-doctoral Fellow/Team Leader. Topic: Data Integration/Semantic Web

K.A.I.S.T. (Korea)

1/5/2012-1/4/2013: Post-doctoral Fellow. Topic: NLP/Semantic Web


1/1/2008-1/4/2012: Dissertation Title: Reasoning about Actions in Transaction Logic [pdf]


Research Interest

I am currently working on enhancing machine learning techniques with semantic data for semantic information extraction, and schema matching. In the past I worked on Ontology Based Data Access (OBDA), Knowledge Representation and Reasoning (KRR) and Natural Language Processing (NLP).

In Ontology Based Data Access (OBDA), the objective is to access data trough a conceptual layer. Usually, this conceptual layer is expressed in the form of an OWL or RDFS ontology, and the data is stored in relational databases. The terms in the conceptual layer are mapped to the data layer using mappings. I have intensively worked on query rewriting techniques for OBDA. That is, answer the queries posed by the user (e.g., SPARQL queries) by translating them into queries over the database (e.g., SQL).

In my Ph.D. dissertation, I worked modeling and reasoning over domains that change over time using Transaction Logic (TR). I extended TR to model and reason with recursive, non-monotonic, and complex actions. I have also worked providing logical reconstructions of the semantics of Production systems in Mu-Calculus, Fix Point logic, and Transaction Logic. Along the same line, I also provided an operational semantics and a model-theoretic semantics for the combination of production systems with description logic ontologies.

Regarding NLP, I have worked on natural language generation, and a framework that allows processing Korean text, efficiently producing RDF triples, and querying the outcome using SPARQL. The final goal was to chain several Korean NLP tools and be able to efficiently publish the outcome on the web linking Korean text entities with Wikipedia/DBpedia.

Selected Publications

''The squids do not frighten me.
To demonstrate them my friendship
I braid and unbraid their tentacles.
After all, I am almost one of them.
I also know how to play and hide
between clouds of ink''.
Ana Shua. - La Surenia.

These are three of my latest publications. To see the complete list please click [Here]
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Accurate Product Attribute Extraction on the Field Information Extraction

We tackled the problem of extracting attribute information from product pages.

To Appear in ICDE 2019
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Efficient SPARQL-to-SQL with R2RML mappings
Data Integration

We proposed a formal approach for SPARQL-to-SQL translation that (i) generates efficient SQL; (ii) provides a well-defined specification of the SPARQL semantics; and (iii) supports R2RML mappings.

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Extracting Semantic Information for e-Commerce Information Extraction

We proposed an approach to automatically tags items with the new semantic information extracted from text and expose them as RDF triple

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Short Bio

I was born in Cordoba, Argentina in 1982. I lived there for 18 years.... same old story, seasons passed, things happened, some reading, no religion. Life. Then I started my studies in computer science at the Facultad de Astronomia, Matematica y Fisica (Universidad Nacional de Cordoba). During that time I also started to practice a contact karate style named Kyokushin. In 2007 I got my master degree, I won a national Kyokushin Torurnament, and I got my diver license. In 2008, I started my PhD studies in Bolzano, Italy and I dived with sharks in Australia... at night. The sharks decided not to eat me. I really appreciate that. In 2009-2010 I went to Stony Brook University (USA) to work with Michael Kifer, and I also started Brazilian Jiu Jitsu. I got 3rd place in the submission only Long Island Tournament. Last but not least, I have always enjoyed taking pictures, writing, climbing, and meeting fun people. I got my PhD on April 2012, and then I went to Korea for a postdoc at KAIST. After 1 year I moved back to Italy and for three years I lead the team developing the OBDA system Ontop. In December 2015 I came to Japan to work as a senior researcher in Rakuten. Nowadays I continue doing the same things: working, training, and jumping from place to place, maybe to escape, just like Qin Shi Huang and his 365 rooms.


Playing guitar, Brazilian Jiu Jitsu/Judo, diving (SSI and PADI certified), Kyokushin Karate, photography**, literature.

** The pictures on this page have been taken by me (except for my profile pic and the one with the Manta ray.)

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