[AISWorld] CALL FOR CHALLENGE - 2nd Linked Open Data-enabled Recommender Systems Challenge @ ESWC 2015
Tommaso Di Noia
tommaso.dinoia at poliba.it
Mon Mar 2 10:16:23 EST 2015
** apologies for cross-posting **
==== Call for Challenge: 2nd Linked Open Data-enabled Recommender
MOTIVATION AND OBJECTIVES
People generally need more and more advanced tools that go beyond those
implementing the canonical search paradigm for seeking relevant
information. A new search paradigm is emerging, where the user's
perspective is completely reversed: from finding to being found.
Recommender systems may help to support this new perspective, because
they have the effect of pushing relevant objects, selected from a large
space of possible options, to potentially interested users. To achieve
this result, recommendation techniques generally rely on data referring
to three kinds of objects: users, items, and their relations.
Recent developments in the Semantic Web community offer novel strategies
to represent data about users, items and their relations that might
improve the current state of the art of recommender systems, in order to
move towards a new generation of recommender systems which fully
understand the items they deal with.
More and more semantic data are published following the Linked Data
principles, that enable links to be set up between objects in different
data sources, by connecting information in a single global data space:
the Web of Data. Today, the Web of Data includes different types of
knowledge represented in a homogeneous form: sedimentary one
(encyclopedic, cultural, linguistic, common-sense) and real-time one
(news, data streams, ...). These data might be useful to interlink
diverse information about users, items, and their relations and
implement reasoning mechanisms that can support and improve the
The primary goal of this challenge is twofold. On the one hand, we want
to enforce the link between the Semantic Web and the Recommender Systems
communities. On the other hand, we aim to showcase how Linked Open Data
and semantic technologies can boost the creation of a new breed of
knowledge-enabled and content-based recommender systems.
The target audience is all of those communities, both academic and
industrial, which are interested in personalized information access with
a particular emphasis on Linked Open Data.
During the last ACM RecSys conference the vast majority of participants
were from industry. This is evidence of the actual interest of
recommender systems for industrial applications ready to be released in
We collected data from Facebook profiles about three distinct domains:
movies, books and musical artists. After a process of anonymization we
then reconciled the data with DBpedia entities. This data will be made
available to train the recommendation algorithms. In order to emphasize
the usefulness of content-based data, only "cold users" will be
available in the dataset.
- Task 1: Top-N recommendations from unary user feedback -
This task deals with the top-N recommendation problem, in which a system
is requested to find and recommend a limited set of N items that best
match a user profile, instead of correctly predicting the ratings for
all available items. In order to favour the proposal of content-based,
LOD-enabled recommendation approaches, and limit the use of
collaborative filtering approaches, this task aims to generate ranked
lists of items for which only unary feedback information (LIKE) is
provided. For this task, we will concentrate only on the movie domain.
- Task 2: Diversity within recommended item sets -
A very interesting aspect of content-based recommender systems, and also
of LOD-enabled ones, is providing the opportunity to evaluate the
diversity of recommended items in a straightforward manner. This is a
very popular topic in content-based recommender systems, which usually
suffer from over-specialization. In this task, the evaluation will be
made by considering a combination of both accuracy of the recommendation
list, and the diversity of items belonging within it. Focusing on
recommending musical artists, we will consider diversity with respect to
- Task 3: Cross-domain recommendation -
This task aims to address a cross-domain recommendation scenario in
which user preferences and/or domain knowledge of a source domain are
used to recommend items in a different target domain. This may
correspond with the following use cases. The first refers to the well
known cold-start problem, which hinders the recommendation generation
due to the lack of sufficient information about users or items. In a
cross-domain setting, a recommender may draw on information acquired
from other domains to alleviate such problem, e.g. a user’s favourite
movie genres may be derived from her favourite book genres. The second
refers to the generation of personalized cross-selling or bundle
recommendations for items from multiple domains, e.g. a movie
accompanied by a music album similar to the soundtrack of the movie.
These relations may not be extracted from rating correlations within a
joined movie-music rating matrix.
In this task, we will request participants to exploit user preferences
and domain knowledge about movies, in order to provide book recommendations.
Making this task highly challenging, we will provide the list of books
available in the test set, but we will provide little information about
the users’ book preferences. Thus, we encourage not (only) to use
collaborative filtering strategies based on correlations between movie
and book preferences, but to investigate approaches that exploit LOD
relating both movies and books domains.
JUDGING AND PRIZES
After a first round of reviews, the Program Committee and the chairs
will select a number of submissions that will have to satisfy the
challenge’s requirements, and will have to be presented at the
conference. Submissions accepted for presentation will receive
constructive reviews from the Program Committee, and will be included in
post-proceedings. All accepted submissions will have a slot in a poster
session dedicated to the challenge. In addition, the winners will
present their work in a special slot of the main program of ESWC’15, and
will be invited to submit a chapter to a post-proceedings book published
by Springer (Communications in Computer and Information Science series).
For each task we will select:
* the best performing tool, given to the paper which will get the
highest score in the evaluation
* the most original approach, selected by the Challenge Program
Committee with the reviewing process
HOW TO PARTICIPATE
We invite the potential participants to subscribe to our mailing list in
order to be kept up to date with the latest news related to the challenge.
lod-recsys-challenge-2015 at googlegroups.com
* Make your result submission
- Register your group using the registration web form available at
- Choose one or more tasks among Task1, Task2 and Task3 (see Tasks).
- Build your Recommendation System using the training data described in
- Evaluate your approach by submitting your results using the evaluation
service as described in section Evaluation.
- Your final score will be the one computed with respect to the last
result submission made before March 25, 2015, 23:59 CET.
* Submit your paper
The following information has to be provided:
- Abstract: no more than 200 words.
- Description: It should contain the details of the system, including
why the system is innovative, how it uses Semantic Web, which features
or functions the system provides, what design choices were made, and
what lessons were learned. The description should also summarize how
participants have addressed the evaluation tasks and the results
evaluation. Papers must be submitted in PDF format, following the style
of the Springer’s Lecture Notes in Computer Science (LNCS) series
(http://www.springer.com/computer/lncs/lncs+authors), and not exceeding
12 pages in length.
All submissions should be provided via EasyChair
* Wednesday, March 25, 2015, 23:59 CET: Paper and Results Submission due
* Thursday, April 16, 2015, 23:59 CET: Notification of acceptance and
submission of task results
* May 31- June 4, 2015: The Challenge takes place at ESWC-15
* Iván Cantador – Universidad Autónoma de Madrid, Spain
* Tommaso Di Noia – Polytechnic University of Bari, Italy
* Vito Claudio Ostuni – Pandora Media, Inc. USA
* Matthew Rowe – University of Lancaster, UK
* Roi Blanco, Yahoo! Labs, Barcelona, Spain
* Pablo Castells, Universidad Autónoma de Madrid, Spain
* Miriam Fernández, The Knowledge Media Institute, The Open University, UK
* Ignacio Fernández-Tobías, Universidad Autónoma de Madrid, Spain
* Frank Hopfgartner, Technische Universität Berlin, Germany
* Julia Hoxha, Columbia University, USA
* Dietmar Jannach, TU Dortmund University, Germany
* Pasquale Lops, University of Bari Aldo Moro, Italy
* Valentina Maccatrozzo, VU University Amsterdam, The Netherlands
* Alexandre Passant, Clarity.fm, USA
* Mariano Rico, Universidad Politécnica de Madrid, Spain
* Giovanni Semeraro, University of Bari Aldo Moro, Italy
* Manolis Wallace, University of Peloponnese, Greece
* Markus Zanker, Alpen-Adria-Universitaet Klagenfurt, Austria
* Paolo Tomeo, Polytechnic University of Bari, Italy
ESWC CHALLENGE COORDINATORS
* Elena Cabrio, INRIA Sophia-Antipolis Méditerranée, France
* Milan Stankovic, Sépage & Université Paris-Sorbonne, France
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