=Paper=
{{Paper
|id=Vol-1866/invited_paper_14
|storemode=property
|title=CLEF 2017 Microblog Cultural Contextualization Content Analysis task Overview
|pdfUrl=https://ceur-ws.org/Vol-1866/invited_paper_14.pdf
|volume=Vol-1866
|authors=Liana Ermakova,Josiane Mothe,Eric Sanjuan
|dblpUrl=https://dblp.org/rec/conf/clef/ErmakovaMS17
}}
==CLEF 2017 Microblog Cultural Contextualization Content Analysis task Overview==
CLEF 2017 Microblog Cultural
Contextualization Content Analysis Task
Overview
Liana Ermakova1 , Josiane Mothe2 , and Eric SanJuan3
1
LISIS (UPEM, INRA, ESIEE, CNRS), Université de Lorraine, France
2
IRIT, UMR5505 CNRS, ESPE, Université de Toulouse, France
3
LIA, Université d’Avignon, France
liana.ermakova@univ-lorraine.fr, josiane.mothe@irit.fr,
eric.sanjuan@univ-avignon.fr
Abstract. The MC2 CLEF 2017 Content Analysis task deals with clas-
sification, filtering, language recognition, localization, entity extraction,
linking open data, and summarization. Festivals have a large presence
on social media. The resulting microblog stream and related URLs are
appropriate to experiment on advanced social media search and min-
ing methods. For content analysis, topics were in any language and re-
sults were expected in four languages: English, Spanish, French, and
Portuguese.
Keywords: Information retrieval, Tweet contextualization, Microblog
analysis, CLEF evaluation forum
1 Introduction
Microblog Contextualization was introduced as a Question Answering task of
INEX 2011 [1]. The main idea was to help Twitter users to understand a tweet by
providing some context associated to it. It has evolved in a Focus IR (Information
Retrieval) task over Wikipedia [2].
The CLEF 2016 Cultural Microblog Contextualization Workshop considered
specific cultural Twitter feeds [3]. In this restricted context, implicit localization
and language identification appeared to be important issues. It also required
identifying implicit timelines over long periods. The MC2 CLEF 2017 lab has
been centered on Cultural Contextualization based on microblog feeds. It dealt
with how cultural context of a microblog affects its social impact at large [4].
This involved microblog search, classification, filtering, language recognition, lo-
calization, entity extraction, linking open data, and summarization.
Given a stream of microblogs, the task consists in:
1. filtering microblogs dealing with festivals;
2. language identification;
3. event localization;
4. author categorization (official account, participant, follower or scam);
5. Wikipedia entity recognition and translation into four target languages: En-
glish, Spanish, Portuguese, and French;
6. automatic summarization of linked Wikipedia pages in the four target lan-
guages.
Each item is evaluated independently, however language identification could
impact Wikipedia linking and the resulting summaries.
In this paper, Section 2 depicts the data used. Section 3 describes the base-
lines and state-of-the-art system. Section 4 describes participant approaches.
Finally, Section 5 draws some conclusions.
2 Data
The MC2 Content Analysis 2017 task provides a set of 1,100 microblogs in 20
languages to be mapped into textual extracts from English, Spanish, French,
and Portuguese Wikipedia.
2.1 Wikipedia XML Corpus
Wikipedia is under a Creative Commons license and its content can be used to
contextualize tweets or to build complex queries referring to Wikipedia entities.
We have extracted an average of 10 million XML documents from Wikipedia
per year since 2012 in the four main Twitter languages: English (en), Spanish
(es), French (fr), and Portuguese (pt). The corpus and tools to process them are
available on the Tweet Contextualization website4 .
These documents reproduce, in an easy-to-use XML structure, the content
of the main Wikipedia pages: title, abstract, section, and subsections, as well as
Wikipedia internal links. Other content such as images, footnotes, and external
links is stripped out in order to obtain a corpus that is easier to process using
standard NLP (Natural Language Processing) tools.
2.2 Queries
The query collection is a pool of 1,100 microblogs extracted from the microblog
stream presented at the CLEF 2016 workshop [5](see also [6]). These microblogs
have more than 80 characters, they do not contain URLs and are written in
more than 20 different languages. The main languages are: en (60%), es (14%),
fr (5%), pt (4%), it (2%). Other languages are: ja, de, nl, tr, id, ca, eu, zh, ru,
sr, pl, ko, fi and ar.
4
http://tc.talne.eu
3 Baselines and State-of-the-art System
For each Wikipedia we provided an XML retrieval system powered by Indri, a
Perl API for the XML retrieval system using standard LWP (short for ”Library
for WWW in Perl”), the corpus in a single XML file (gzip compression), and
the corpus split into 1,000 folders, one file per page (tgz archive). However these
baselines did not provide text segmentation into sentences nor an automatic
summarization tool. They only allowed to retrieve XML elements based on nested
language models.
Based on these resources the available baselines are:
– filtering: based on the word ”festival”;
– language: based on Twitter local code;
– entity extraction: top ranked Wikipedia page titles based on a document
language model;
– summarization: based on Wikipedia page abstracts.
A state-of-the-art contextualization system has also been used to generate
a complete run available for active participants. This reference system is based
on the Terrier platform5 . Wikipedia pages in English, French, Spanish, and Por-
tuguese were stemmed by the SnowBall stemmer. The pages retrieved by the
InL2 model with Bo1 query expansion technique were interpreted as a baseline
for the entity recognition subtask. Then, documents were parsed by Stanford
CoreNLP in order to perform sentence chunking and lemmatization 6 . For the
automatic summarization subtask we used the following baselines:
– the first passage from the top-scored Wikipedia page;
– the cosine similarity between a tweet and a candidate sentence;
– word2vec similarity between a tweet and a candidate sentence [7];
– the system based on local context analysis presented at CLEF-2015 [8].
4 Participants Approaches
Each item has been evaluated independently, however, language identification
could impact Wikipedia linking and the resulting summaries. The filtering and
author categorization subtasks were inspired by the filtering and priority tasks
at RepLab 2014 [9].
4.1 Filtering and Opinion Mining
One participant (LIA-FR) scored all microblogs by proximity with a festival
topic [10]. Opinion mining was not initially considered, however one partici-
pant (ISAMM-TN) did apply binary opinion classifiers [11]. It appeared that
microblog interestingness about festivals assessed by organizers mostly relies on
neutral microblogs because they are easier to understand without context.
5
http://terrier.org/
6
https://stanfordnlp.github.io/CoreNLP/
4.2 Language Identification
Language identification is challenging over short content that tends to mix sev-
eral languages. Indeed, festival names over tweets often appear in English but
the rest of the content can be in any other language. Moreover, festival attendees
tend to add terms from various dialects to highlight the local context.
Using linguistic resources for main languages as Syllabs-FR did, allow to
reach the best precision scores [12]. However, based on statistical approaches,
the LIA-FR identified 121 errors in microblog local information among the 1,100
[13]. After evaluation, it appeared that 90 among the 121 were true errors: 30%
about en, 20% about pt, 16% about es, 10% about id. The rest of true errors
were about it, de, sh, fr, nl, ceb, ca, and sv.
4.3 Event Localization
Event localization requires external resources. For large festivals, Wikipedia of-
ten contains the information and it can be retrieved based on state-of-the-art
QA (Question Answering) approaches. However for small events it is necessary
to query the public web or social networks. The Syllabs-FR team managed to
localize festivals in France using public information [12].
4.4 Entity Recognition and Automatic Summarization
The two subtasks: Wikipedia Entity Recognition and Automatic Summarization
refer to previous experiments around Tweet Contextualization[2]. The most ef-
ficient methods proceed in two steps: 1) retrieve the most relevant Wikipedia
pages, 2) propose a multidocument summary of them. Wikifying tweets is com-
plex due to the lexical gap between tweets and Wikipedia pages. Extracting
summaries looked easier by aggregating sentences from pages, however ensuring
and evaluating readability is an issue, especially with languages that have less
resources than English.
The FELTS system managed to identify all Wikipedia page titles that explic-
itly appear in the 1,100 microblogs for the four target languages [13]. Multiword
titles are often unambiguous. Among the 1,100 queries, 818 of them contained
explicit references to unambiguous Wikipedia pages in English, 536 in Spanish,
485 in French, and 459 in Portuguese. By considering the Wikipedia abstract of
these pages, it was then possible to directly extract high quality summaries con-
textualizing almost half of the topics in the four target languages. This approach
has bean scaled to process microblog streams in real time.
5 Conclusion
Dealing with a massive multilingual multicultural corpus of microblogs reveals
the limits of both statistical and linguistic approaches. It also requires linguistic
resources for each language or for specific cultural events. Therefore language
and festival recognition appeared to be the key points of the overall MC2 CLEF
2017 lab official tasks.
Researchers interested in using MC2 Lab data and infrastructure, but who
did not participate to the 2017 edition, can apply until March 2019 to get access
to the data and baseline system for their academic institution by contacting
eric.sanjuan@talne.eu. Once the application is accepted, they will get a per-
sonal private login to gain access to lab resources for research purposes.
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