Annonce en lien avec l’Action/le Réseau : aucun
Laboratoire/Entreprise : ETIS
Durée : 6 mois
Contact : Dimitrios.Kotzinos@u-cergy.fr
Date limite de publication : 2016-03-31
Contexte :
The internship will take place in the MIDI team of the ETIS Lab (ENSEA / UCP / CNRS UMR 8051) based in the area of Cergy Pontoise, just outside Paris.
The internship will have a net salary of around 508 euros/month and a duration of up to 6 months, starting on March or April 2017.
Interested candidates are requested to send a detailed CV, one recommendation letter and university/master transcripts to Katerina Tzompanaki at atzompan@u-cergy.fr.
Sujet :
Repairing SQL queries to retrieve missing answers.
The increasing load of data produced nowadays is coupled with an increasing need for complex data transformations that developers design in order to process or integrate these data. These transformations, commonly specified declaratively in the form of queries, may fail to produce all the expected results leading to what we call missing data. Understanding the reasons why missing data occur, and how the original query can be modified in order to overcome these reasons, can be tricky if manually performed. In the context of relational databases, [1] proposed a novel way (Why-Not polynomials) to explain missing data given a certain query. Consequently, [3] described a first approach of utilizing Why-Not polynomials in order to effectively repair the query, while [2] shows a prototype implementing these algorithms. As the query repairing phase of the framework heavily depends on the size of the database and the complexity of the Why-Not polynomial, a more efficient solution needs to be devised, either by improving the existing algorithm or by proposing a new one. This will be the focus of the master internship.
More specifically, the candidate is expected to
1) Verify/Identify the bottlenecks of the existing solution, algorithmically and experimentally.
2) Propose improvements of the algorithm.
3) Implement the new improved algorithm and experimentally prove its efficiency.
References
[1] Bidoit, Nicole, Melanie Herschel, and Aikaterini Tzompanaki. “Efficient computation of polynomial explanations of why-not questions.” Proceedings of the 24th ACM International on Conference on Information and Knowledge Management. ACM, 2015.
[2] Bidoit, Nicole, Melanie Herschel, and Katerina Tzompanaki. “EFQ: Why-not answer polynomials in action.” Proceedings of the VLDB Endowment 8.12, 2015.
[3] Bidoit, Nicole, Melanie Herschel, and Katerina Tzompanaki. “Refining SQL Queries based on Why-Not Polynomials.” 8th USENIX Workshop on the Theory and Practice of Provenance (TaPP 2016). 2016.
Profil du candidat :
The candidate shoukd be an M2 level student.
Formation et compétences requises :
The candidate will have solid knowledge of the Java programming language. Familiarity with SQL query language and relational databases is desired.
Adresse d’emploi :
MIDI team
ETIS Lab (ENSEA / UCP / CNRS UMR 8051)
Site St. Martin
2 Av. Adolph Chauvin
95000 Pontoise