9,671 research outputs found
Detecting Real-World Influence Through Twitter
In this paper, we investigate the issue of detecting the real-life influence
of people based on their Twitter account. We propose an overview of common
Twitter features used to characterize such accounts and their activity, and
show that these are inefficient in this context. In particular, retweets and
followers numbers, and Klout score are not relevant to our analysis. We thus
propose several Machine Learning approaches based on Natural Language
Processing and Social Network Analysis to label Twitter users as Influencers or
not. We also rank them according to a predicted influence level. Our proposals
are evaluated over the CLEF RepLab 2014 dataset, and outmatch state-of-the-art
ranking methods.Comment: 2nd European Network Intelligence Conference (ENIC), Sep 2015,
Karlskrona, Swede
Learning to Rank Academic Experts in the DBLP Dataset
Expert finding is an information retrieval task that is concerned with the
search for the most knowledgeable people with respect to a specific topic, and
the search is based on documents that describe people's activities. The task
involves taking a user query as input and returning a list of people who are
sorted by their level of expertise with respect to the user query. Despite
recent interest in the area, the current state-of-the-art techniques lack in
principled approaches for optimally combining different sources of evidence.
This article proposes two frameworks for combining multiple estimators of
expertise. These estimators are derived from textual contents, from
graph-structure of the citation patterns for the community of experts, and from
profile information about the experts. More specifically, this article explores
the use of supervised learning to rank methods, as well as rank aggregation
approaches, for combing all of the estimators of expertise. Several supervised
learning algorithms, which are representative of the pointwise, pairwise and
listwise approaches, were tested, and various state-of-the-art data fusion
techniques were also explored for the rank aggregation framework. Experiments
that were performed on a dataset of academic publications from the Computer
Science domain attest the adequacy of the proposed approaches.Comment: Expert Systems, 2013. arXiv admin note: text overlap with
arXiv:1302.041
MoralStrength: Exploiting a Moral Lexicon and Embedding Similarity for Moral Foundations Prediction
Moral rhetoric plays a fundamental role in how we perceive and interpret the
information we receive, greatly influencing our decision-making process.
Especially when it comes to controversial social and political issues, our
opinions and attitudes are hardly ever based on evidence alone. The Moral
Foundations Dictionary (MFD) was developed to operationalize moral values in
the text. In this study, we present MoralStrength, a lexicon of approximately
1,000 lemmas, obtained as an extension of the Moral Foundations Dictionary,
based on WordNet synsets. Moreover, for each lemma it provides with a
crowdsourced numeric assessment of Moral Valence, indicating the strength with
which a lemma is expressing the specific value. We evaluated the predictive
potentials of this moral lexicon, defining three utilization approaches of
increased complexity, ranging from lemmas' statistical properties to a deep
learning approach of word embeddings based on semantic similarity. Logistic
regression models trained on the features extracted from MoralStrength,
significantly outperformed the current state-of-the-art, reaching an F1-score
of 87.6% over the previous 62.4% (p-value<0.01), and an average F1-Score of
86.25% over six different datasets. Such findings pave the way for further
research, allowing for an in-depth understanding of moral narratives in text
for a wide range of social issues
How to Ask for a Favor: A Case Study on the Success of Altruistic Requests
Requests are at the core of many social media systems such as question &
answer sites and online philanthropy communities. While the success of such
requests is critical to the success of the community, the factors that lead
community members to satisfy a request are largely unknown. Success of a
request depends on factors like who is asking, how they are asking, when are
they asking, and most critically what is being requested, ranging from small
favors to substantial monetary donations. We present a case study of altruistic
requests in an online community where all requests ask for the very same
contribution and do not offer anything tangible in return, allowing us to
disentangle what is requested from textual and social factors. Drawing from
social psychology literature, we extract high-level social features from text
that operationalize social relations between recipient and donor and
demonstrate that these extracted relations are predictive of success. More
specifically, we find that clearly communicating need through the narrative is
essential and that that linguistic indications of gratitude, evidentiality, and
generalized reciprocity, as well as high status of the asker further increase
the likelihood of success. Building on this understanding, we develop a model
that can predict the success of unseen requests, significantly improving over
several baselines. We link these findings to research in psychology on helping
behavior, providing a basis for further analysis of success in social media
systems.Comment: To appear at ICWSM 2014. 10pp, 3 fig. Data and other info available
at http://www.mpi-sws.org/~cristian/How_to_Ask_for_a_Favor.htm
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