VLDB 2026 Research / reviewers in the wild / expert
Yelena Mejova
dblp:29/758
· DBLP profile ↗
18ranked-venue papers in the field
6as first author
5since 2021 · last 2026
0000-0001-5560-4109ORCID · corroborated
Domains — venue-derived; a paper can count in several
Information Retrieval & Web Search · 17 (5 first)Data Mining & Knowledge Discovery · 1 (1 first)
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Language-Agnostic Modeling of Source Reliability on WikipediaabstractOver the last few years, verifying the credibility of information sources has become a fundamental need to combat disinformation. Here, we present a language-agnostic model designed to assess the reliability of web domains as sources in references across multiple language editions of Wikipedia. Utilizing editing activity data, the model evaluates domain reliability within different articles of varying controversiality, such as Climate Change, COVID-19, History, Media, and Biology topics. Crafting features that express domain usage across articles, the model effectively predicts domain reliability, achieving an F1 Macro score of approximately 0.80 for English and other high-resource languages. For mid-resource languages, we achieve 0.65, while the performance of low-resource languages varies. In all cases, the time the domain remains present in the articles (which we dub as permanence ) is one of the most predictive features. We highlight the challenge of maintaining consistent model performance across languages of varying resource levels and demonstrate that adapting models from higher-resource languages can improve performance. We believe these findings can assist Wikipedia editors in their ongoing efforts to verify citations and may offer useful insights for other user-generated content communities. Jacopo D'Ignazi, Andreas Kaltenbrunner, Yelena Mejova, Michele Tizzani, Kyriaki Kalimeri, Mariano G. Beiró, Pablo Aragón |
ACM Trans. Web | 3 |
| 2023 | Authority without Care: Moral Values behind the Mask Mandate ResponseabstractFace masks are one of the cheapest and most effective non-pharmaceutical interventions available against airborne diseases such as COVID-19. Unfortunately, they have been met with resistance by a substantial fraction of the populace, especially in the U.S. In this study, we uncover the latent moral values that underpin the response to the mask mandate, and paint them against the country's political backdrop. We monitor the discussion about masks on Twitter, which involves almost 600k users in a time span of 7 months. By using a combination of graph mining, natural language processing, topic modeling, content analysis, and time series analysis, we characterize the responses to the mask mandate of both those in favor and against them. We base our analysis on the theoretical frameworks of Moral Foundation Theory and Hofstede's cultural dimensions. Our results show that, while the anti-mask stance is associated with a conservative political leaning, the moral values expressed by its adherents diverge from the ones typically used by conservatives. In particular, the expected emphasis on the values of authority and purity is accompanied by an atypical dearth of in-group loyalty. We find that after the mandate, both pro- and anti-mask sides decrease their emphasis on care about others, and increase their attention on authority and fairness, further politicizing the issue. In addition, the mask mandate reverses the expression of Individualism-Collectivism between the two sides, with an increase of individualism in the anti-mask narrative, and a decrease in the pro-mask one. We argue that monitoring the dynamics of moral positioning is crucial for designing effective public health campaigns that are sensitive to the underlying values of the target audience. Yelena Mejova, Kyriaki Kalimeri, Gianmarco De Francisci Morales |
ICWSM | 1 |
| 2023 | Comfort Foods and Community Connectedness: Investigating Diet Change during COVID-19 Using YouTube Videos on TwitterabstractUnprecedented lockdowns at the start of the COVID-19 pandemic have drastically changed the routines of millions of people, potentially impacting important health-related behaviors. In this study, we use YouTube videos embedded in tweets about diet, exercise and fitness posted before and during COVID-19 to investigate the influence of the pandemic lockdowns on diet and nutrition. In particular, we examine the nutritional profile of the foods mentioned in the transcript, description and title of each video in terms of six macronutrients (protein, energy, fat, sodium, sugar, and saturated fat). These macronutrient values were further linked to demographics to assess if there are specific effects on those potentially having insufficient access to healthy sources of food. Interrupted time series analysis revealed a considerable shift in the aggregated macronutrient scores before and during COVID-19. In particular, whereas areas with lower incomes showed decrease in energy, fat, and saturated fat, those with higher percentage of African Americans showed an elevation in sodium. Word2Vec word similarities and odds ratio analysis suggested a shift from popular diets and lifestyle bloggers before the lockdowns to the interest in a variety of healthy foods, communal sharing of quick and easy recipes, as well as a new emphasis on comfort foods. To the best of our knowledge, this work is novel in terms of linking attention signals in tweets, content of videos, their nutrients profile, and aggregate demographics of the users. The insights made possible by this combination of resources are important for monitoring the secondary health effects of social distancing, and informing social programs designed to alleviate these effects. Yelena Mejova, Lydia Manikonda |
ICWSM | 1 |
| 2023 | The Thin Ideology of Populist Advertising on Facebook during the 2019 EU ElectionsabstractSocial media has been an important tool in the expansion of the populist message, and it is thought to have contributed to the electoral success of populist parties in the past decade. This study compares how populist parties advertised on Facebook during the 2019 European Parliamentary election. In particular, we examine commonalities and differences in which audiences they reach and on which issues they focus. By using data from Meta (previously Facebook) Ad Library, we analyze 45k ad campaigns by 39 parties, both populist and mainstream, in Germany, United Kingdom, Italy, Spain, and Poland. While populist parties represent just over 20% of the total expenditure on political ads, they account for 40% of the total impressions—most of which from Eurosceptic and far-right parties—thus hinting at a competitive advantage for populist parties on Facebook. We further find that ads posted by populist parties are more likely to reach male audiences, and sometimes much older ones. In terms of issues, populist politicians focus on monetary policy, state bureaucracy and reforms, and security, while the focus on EU and Brexit is on par with non-populist, mainstream parties. However, issue preferences are largely country-specific, thus supporting the view in political science that populism is a “thin ideology”, that does not have a universal, coherent policy agenda. This study illustrates the usefulness of publicly available advertising data for monitoring the populist outreach to, and engagement with, millions of potential voters, while outlining the limitations of currently available data. Arthur Capozzi, Gianmarco De Francisci Morales, Yelena Mejova, Corrado Monti, André Panisson |
WWW | 3 |
| 2022 | Echoes through Time: Evolution of the Italian COVID-19 Vaccination Debate
Giuseppe Crupi, Yelena Mejova, Michele Tizzani, Daniela Paolotti, André Panisson |
ICWSM | 2 |
| 2020 | Falling into the Echo Chamber: The Italian Vaccination Debate on Twitter
Alessandro Cossard, Gianmarco De Francisci Morales, Kyriaki Kalimeri, Yelena Mejova, Daniela Paolotti, Michele Starnini |
ICWSM | 4 |
| 2020 | Facebook Ads as a Demographic Tool to Measure the Urban-Rural DivideabstractIn the global move toward urbanization, making sure the people remaining in rural areas are not left behind in terms of development and policy considerations is a priority for governments worldwide. However, it is increasingly challenging to track important statistics concerning this sparse, geographically dispersed population, resulting in a lack of reliable, up-to-date data. In this study, we examine the usefulness of the Facebook Advertising platform, which offers a digital “census” of over two billions of its users, in measuring potential rural-urban inequalities. We focus on Italy, a country where about 30% of the population lives in rural areas. First, we show that the population statistics that Facebook produces suffer from instability across time and incomplete coverage of sparsely populated municipalities. To overcome such limitation, we propose an alternative methodology for estimating Facebook Ads audiences that nearly triples the coverage of the rural municipalities from 19% to 55% and makes feasible fine-grained sub-population analysis. Using official national census data, we evaluate our approach and confirm known significant urban-rural divides in terms of educational attainment and income. Extending the analysis to Facebook-specific user “interests” and behaviors, we provide further insights on the divide, for instance, finding that rural areas show a higher interest in gambling. Notably, we find that the most predictive features of income in rural areas differ from those for urban centres, suggesting researchers need to consider a broader range of attributes when examining rural wellbeing. The findings of this study illustrate the necessity of improving existing tools and methodologies to include under-represented populations in digital demographic studies – the failure to do so could result in misleading observations, conclusions, and most importantly, policies. Daniele Rama, Yelena Mejova, Michele Tizzoni, Kyriaki Kalimeri, Ingmar Weber |
WWW | 2 |
| 2017 | Visualizing Health Awareness in the Middle East
Matheus Araújo 0001, Yelena Mejova, Michaël Aupetit 0001, Ingmar Weber |
ICWSM | 2 |
| 2016 | Are You Charlie or Ahmed? Cultural Pluralism in Charlie Hebdo Response on Twitter
Jisun An, Haewoon Kwak, Yelena Mejova, Sonia Alonso Saenz De Oger, Braulio Gomez Fortes |
ICWSM | 3 |
| 2016 | Fetishizing Food in Digital Age: #foodporn Around the World
Yelena Mejova, Sofiane Abbar, Hamed Haddadi 0001 |
ICWSM | 1 |
| 2016 | Beyond entities: promoting explorative search with bundles
Ilaria Bordino, Mounia Lalmas-Roelleke, Yelena Mejova, Olivier Van Laere |
Inf. Retr. J. | 3 |
| 2014 | DEESSE: entity-Driven Exploratory and sErendipitous Search SystEmabstractWe present DEESSE [1], a tool that enables an exploratory and serendipitous exploration - at entity level, of the content of two different social media: Wikipedia, a user-curated online encyclopedia, and Yahoo Answers, a more unconstrained question/answering forum. DEESSE represents the content of each source as an entity network, which is further enriched with metadata about sentiment, writing quality, and topical category. Given a query entity, entity results are retrieved from the network by employing an algorithm based on a random walk with restart to the query. Following the emerging paradigm of composite retrieval, we organize the results into topically coherent bundles instead of showing them in a simple ranked list. Olivier Van Laere, Ilaria Bordino, Yelena Mejova, Mounia Lalmas-Roelleke |
CIKM | 3 |
| 2013 | Penguins in sweaters, or serendipitous entity search on user-generated contentabstractIn many cases, when browsing the Web users are searching for specific information or answers to concrete questions. Sometimes, though, users find unexpected, yet interesting and useful results, and are encouraged to explore further. What makes a result serendipitous? We propose to answer this question by exploring the potential of entities extracted from two sources of user-generated content -- Wikipedia, a user-curated online encyclopedia, and Yahoo! Answers, a more unconstrained question/answering forum -- in promoting serendipitous search. In this work, the content of each data source is represented as an entity network, which is further enriched with metadata about sentiment, writing quality, and topical category. We devise an algorithm based on lazy random walk with restart to retrieve entity recommendations from the networks. We show that our method provides novel results from both datasets, compared to standard web search engines. However, unlike previous research, we find that choosing highly emotional entities does not increase user interest for many categories of entities, suggesting a more complex relationship between topic matter and the desirable metadata attributes in serendipitous search. Ilaria Bordino, Yelena Mejova, Mounia Lalmas-Roelleke |
CIKM | 2 |
| 2013 | Detecting Friday Night Party Photos: Semantics for Tag Recommendation
Philip J. McParlane, Yelena Mejova, Ingmar Weber |
ECIR | 2 |
| 2013 | GOP primary season on twitter: "popular" political sentiment in social mediaabstractAs mainstream news media and political campaigns start to pay attention to the political discourse online, a systematic analysis of political speech in social media becomes more critical. What exactly do people say on these sites, and how useful is this data in estimating political popularity? In this study we examine Twitter discussions surrounding seven US Republican politicians who were running for the US Presidential nomination in 2011. We show this largely negative rhetoric to be laced with sarcasm and humor and dominated by a small portion of users. Furthermore, we show that using out-of-the-box classification tools results in a poor performance, and instead develop a highly optimized multi-stage approach designed for general-purpose political sentiment classification. Finally, we compare the change in sentiment detected in our dataset before and after 19 Republican debates, concluding that, at least in this case, the Twitter political chatter is not indicative of national political polls. Yelena Mejova, Padmini Srinivasan, Bob Boynton |
WSDM | 1 |
| 2012 | Crossing Media Streams with Sentiment: Domain Adaptation in Blogs, Reviews and Twitter
Yelena Mejova, Padmini Srinivasan |
ICWSM | 1 |
| 2011 | Exploring Feature Definition and Selection for Sentiment Classifiers
Yelena Mejova, Padmini Srinivasan |
ICWSM | 1 |
| 2009 | A relevance-based topic model for news event trackingabstractEvent tracking is the task of discovering temporal patterns of popular events from text streams. Existing approaches for event tracking have two limitations: scalability and inability to rule out non-relevant portions in text streams. In this study, we propose a novel approach to tackle these limitations. To demonstrate the approach, we track news events across a collection of weblogs spanning a two-month time period. Viet Ha-Thuc, Yelena Mejova, Christopher G. Harris 0001, Padmini Srinivasan |
SIGIR | 2 |