3,233 research outputs found
Exploiting multimedia in creating and analysing multimedia Web archives
The data contained on the web and the social web are inherently multimedia and consist of a mixture of textual, visual and audio modalities. Community memories embodied on the web and social web contain a rich mixture of data from these modalities. In many ways, the web is the greatest resource ever created by human-kind. However, due to the dynamic and distributed nature of the web, its content changes, appears and disappears on a daily basis. Web archiving provides a way of capturing snapshots of (parts of) the web for preservation and future analysis. This paper provides an overview of techniques we have developed within the context of the EU funded ARCOMEM (ARchiving COmmunity MEMories) project to allow multimedia web content to be leveraged during the archival process and for post-archival analysis. Through a set of use cases, we explore several practical applications of multimedia analytics within the realm of web archiving, web archive analysis and multimedia data on the web in general
SentiBench - a benchmark comparison of state-of-the-practice sentiment analysis methods
In the last few years thousands of scientific papers have investigated
sentiment analysis, several startups that measure opinions on real data have
emerged and a number of innovative products related to this theme have been
developed. There are multiple methods for measuring sentiments, including
lexical-based and supervised machine learning methods. Despite the vast
interest on the theme and wide popularity of some methods, it is unclear which
one is better for identifying the polarity (i.e., positive or negative) of a
message. Accordingly, there is a strong need to conduct a thorough
apple-to-apple comparison of sentiment analysis methods, \textit{as they are
used in practice}, across multiple datasets originated from different data
sources. Such a comparison is key for understanding the potential limitations,
advantages, and disadvantages of popular methods. This article aims at filling
this gap by presenting a benchmark comparison of twenty-four popular sentiment
analysis methods (which we call the state-of-the-practice methods). Our
evaluation is based on a benchmark of eighteen labeled datasets, covering
messages posted on social networks, movie and product reviews, as well as
opinions and comments in news articles. Our results highlight the extent to
which the prediction performance of these methods varies considerably across
datasets. Aiming at boosting the development of this research area, we open the
methods' codes and datasets used in this article, deploying them in a benchmark
system, which provides an open API for accessing and comparing sentence-level
sentiment analysis methods
Crowdbreaks: Tracking Health Trends using Public Social Media Data and Crowdsourcing
In the past decade, tracking health trends using social media data has shown
great promise, due to a powerful combination of massive adoption of social
media around the world, and increasingly potent hardware and software that
enables us to work with these new big data streams. At the same time, many
challenging problems have been identified. First, there is often a mismatch
between how rapidly online data can change, and how rapidly algorithms are
updated, which means that there is limited reusability for algorithms trained
on past data as their performance decreases over time. Second, much of the work
is focusing on specific issues during a specific past period in time, even
though public health institutions would need flexible tools to assess multiple
evolving situations in real time. Third, most tools providing such capabilities
are proprietary systems with little algorithmic or data transparency, and thus
little buy-in from the global public health and research community. Here, we
introduce Crowdbreaks, an open platform which allows tracking of health trends
by making use of continuous crowdsourced labelling of public social media
content. The system is built in a way which automatizes the typical workflow
from data collection, filtering, labelling and training of machine learning
classifiers and therefore can greatly accelerate the research process in the
public health domain. This work introduces the technical aspects of the
platform and explores its future use cases
Emotions, Demographics and Sociability in Twitter Interactions
The social connections people form online affect the quality of information
they receive and their online experience. Although a host of socioeconomic and
cognitive factors were implicated in the formation of offline social ties, few
of them have been empirically validated, particularly in an online setting. In
this study, we analyze a large corpus of geo-referenced messages, or tweets,
posted by social media users from a major US metropolitan area. We linked these
tweets to US Census data through their locations. This allowed us to measure
emotions expressed in the tweets posted from an area, the structure of social
connections, and also use that area's socioeconomic characteristics in
analysis. %We extracted the structure of online social interactions from the
people mentioned in tweets from that area. We find that at an aggregate level,
places where social media users engage more deeply with less diverse social
contacts are those where they express more negative emotions, like sadness and
anger. Demographics also has an impact: these places have residents with lower
household income and education levels. Conversely, places where people engage
less frequently but with diverse contacts have happier, more positive messages
posted from them and also have better educated, younger, more affluent
residents. Results suggest that cognitive factors and offline characteristics
affect the quality of online interactions. Our work highlights the value of
linking social media data to traditional data sources, such as US Census, to
drive novel analysis of online behavior.Comment: International Conference on the Web and Social Media (ICWSM2016
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