208 research outputs found
Adaptive Representations for Tracking Breaking News on Twitter
Twitter is often the most up-to-date source for finding and tracking breaking
news stories. Therefore, there is considerable interest in developing filters
for tweet streams in order to track and summarize stories. This is a
non-trivial text analytics task as tweets are short, and standard retrieval
methods often fail as stories evolve over time. In this paper we examine the
effectiveness of adaptive mechanisms for tracking and summarizing breaking news
stories. We evaluate the effectiveness of these mechanisms on a number of
recent news events for which manually curated timelines are available.
Assessments based on ROUGE metrics indicate that an adaptive approaches are
best suited for tracking evolving stories on Twitter.Comment: 8 Pag
Exploring the Relationship between Membership Turnover and Productivity in Online Communities
One of the more disruptive reforms associated with the modern Internet is the
emergence of online communities working together on knowledge artefacts such as
Wikipedia and OpenStreetMap. Recently it has become clear that these
initiatives are vulnerable because of problems with membership turnover. This
study presents a longitudinal analysis of 891 WikiProjects where we model the
impact of member turnover and social capital losses on project productivity. By
examining social capital losses we attempt to provide a more nuanced analysis
of member turnover. In this context social capital is modelled from a social
network perspective where the loss of more central members has more impact. We
find that only a small proportion of WikiProjects are in a relatively healthy
state with low levels of membership turnover and social capital losses. The
results show that the relationship between social capital losses and project
performance is U-shaped, and that member withdrawal has significant negative
effect on project outcomes. The results also support the mediation of turnover
rate and network density on the curvilinear relationship
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