383 research outputs found
Geotagging One Hundred Million Twitter Accounts with Total Variation Minimization
Geographically annotated social media is extremely valuable for modern
information retrieval. However, when researchers can only access
publicly-visible data, one quickly finds that social media users rarely publish
location information. In this work, we provide a method which can geolocate the
overwhelming majority of active Twitter users, independent of their location
sharing preferences, using only publicly-visible Twitter data.
Our method infers an unknown user's location by examining their friend's
locations. We frame the geotagging problem as an optimization over a social
network with a total variation-based objective and provide a scalable and
distributed algorithm for its solution. Furthermore, we show how a robust
estimate of the geographic dispersion of each user's ego network can be used as
a per-user accuracy measure which is effective at removing outlying errors.
Leave-many-out evaluation shows that our method is able to infer location for
101,846,236 Twitter users at a median error of 6.38 km, allowing us to geotag
over 80\% of public tweets.Comment: 9 pages, 8 figures, accepted to IEEE BigData 2014, Compton, Ryan,
David Jurgens, and David Allen. "Geotagging one hundred million twitter
accounts with total variation minimization." Big Data (Big Data), 2014 IEEE
International Conference on. IEEE, 201
Inferring Degree Of Localization Of Twitter Persons And Topics Through Time, Language, And Location Features
Identifying authoritative influencers related to a geographic area (geo-influencers) can aid content recommendation systems and local expert finding. This thesis addresses this important problem using Twitter data.
A geo-influencer is identified via the locations of its followers. On Twitter, due to privacy reasons, the location reported by followers is limited to profile via a textual string or messages with coordinates. However, this textual string is often not possible to geocode and less than 1\% of message traffic provides coordinates. First, the error rates associated with Google\u27s geocoder are studied and a classifier is built that gives a warning for self-reported locations that are likely incorrect. Second, it is shown that city-level geo-influencers can be identified without geocoding by leveraging the power of Google search and follower-followee network structure. Third, we illustrate that the global vs. local influencer, at the timezone level, can be identified using a classifier using the temporal features of the followers. For global influencers, spatiotemporal analysis helps understand the evolution of their popularity over time. When applied over message traffic, the approach can differentiate top trending topics and persons in different geographical regions. Fourth, we constrain a timezone to a set of possible countries and use language features for training a high-level geocoder to further localize an influencer\u27s geographic area. Finally, we provide a repository of geo-influencers for applications related to content recommendation. The repository can be used for filtering influencers based on their audience\u27s demographics related to location, time, language, gender, and ethnicity
MUFFLE: Multi-Modal Fake News Influence Estimator on Twitter
To alleviate the impact of fake news on our society, predicting the popularity of fake news posts on social media is a crucial problem worthy of study. However, most related studies on fake news emphasize detection only. In this paper, we focus on the issue of fake news influence prediction, i.e., inferring how popular a fake news post might become on social platforms. To achieve our goal, we propose a comprehensive framework, MUFFLE, which captures multi-modal dynamics by encoding the representation of news-related social networks, user characteristics, and content in text. The attention mechanism developed in the model can provide explainability for social or psychological analysis. To examine the effectiveness of MUFFLE, we conducted extensive experiments on real-world datasets. The experimental results show that our proposed method outperforms both state-of-the-art methods of popularity prediction and machine-based baselines in top-k NDCG and hit rate. Through the experiments, we also analyze the feature importance for predicting fake news influence via the explainability provided by MUFFLE
Trustworthy LLMs: a Survey and Guideline for Evaluating Large Language Models' Alignment
Ensuring alignment, which refers to making models behave in accordance with
human intentions [1,2], has become a critical task before deploying large
language models (LLMs) in real-world applications. For instance, OpenAI devoted
six months to iteratively aligning GPT-4 before its release [3]. However, a
major challenge faced by practitioners is the lack of clear guidance on
evaluating whether LLM outputs align with social norms, values, and
regulations. This obstacle hinders systematic iteration and deployment of LLMs.
To address this issue, this paper presents a comprehensive survey of key
dimensions that are crucial to consider when assessing LLM trustworthiness. The
survey covers seven major categories of LLM trustworthiness: reliability,
safety, fairness, resistance to misuse, explainability and reasoning, adherence
to social norms, and robustness. Each major category is further divided into
several sub-categories, resulting in a total of 29 sub-categories.
Additionally, a subset of 8 sub-categories is selected for further
investigation, where corresponding measurement studies are designed and
conducted on several widely-used LLMs. The measurement results indicate that,
in general, more aligned models tend to perform better in terms of overall
trustworthiness. However, the effectiveness of alignment varies across the
different trustworthiness categories considered. This highlights the importance
of conducting more fine-grained analyses, testing, and making continuous
improvements on LLM alignment. By shedding light on these key dimensions of LLM
trustworthiness, this paper aims to provide valuable insights and guidance to
practitioners in the field. Understanding and addressing these concerns will be
crucial in achieving reliable and ethically sound deployment of LLMs in various
applications
Unpacking polarization: Antagonism and Alignment in Signed Networks of Online Interaction
Online polarization research currently focuses on studying single-issue
opinion distributions or computing distance metrics of interaction network
structures. Limited data availability often restricts studies to positive
interaction data, which can misrepresent the reality of a discussion. We
introduce a novel framework that aims at combining these three aspects, content
and interactions, as well as their nature (positive or negative), while
challenging the prevailing notion of polarization as an umbrella term for all
forms of online conflict or opposing opinions. In our approach, built on the
concepts of cleavage structures and structural balance of signed social
networks, we factorize polarization into two distinct metrics: Antagonism and
Alignment. Antagonism quantifies hostility in online discussions, based on the
reactions of users to content. Alignment uses signed structural information
encoded in long-term user-user relations on the platform to describe how well
user interactions fit the global and/or traditional sides of discussion. We can
analyse the change of these metrics through time, localizing both relevant
trends but also sudden changes that can be mapped to specific contexts or
events. We apply our methods to two distinct platforms: Birdwatch, a US
crowd-based fact-checking extension of Twitter, and DerStandard, an Austrian
online newspaper with discussion forums. In these two use cases, we find that
our framework is capable of describing the global status of the groups of users
(identification of cleavages) while also providing relevant findings on
specific issues or in specific time frames. Furthermore, we show that our four
metrics describe distinct phenomena, emphasizing their independent
consideration for unpacking polarization complexities
Network Analysis on Incomplete Structures.
Over the past decade, networks have become an increasingly popular abstraction for problems in the physical, life, social and information sciences. Network analysis can be used to extract insights into an underlying system from the structure of its network representation. One of the challenges of applying network analysis is the fact that networks do not always have an observed and complete structure. This dissertation focuses on the problem of imputation and/or inference in the presence of incomplete network structures. I propose four novel systems, each of which, contain a module that involves the inference or imputation of an incomplete network that is necessary to complete the end task.
I first propose EdgeBoost, a meta-algorithm and framework that repeatedly applies a non-deterministic link predictor to improve the efficacy of community detection algorithms on networks with missing edges. On average EdgeBoost improves performance of existing algorithms by 7% on artificial data and 17% on ego networks collected from Facebook. The second system, Butterworth, identifies a social network user's topic(s) of interests and automatically generates a set of social feed ``rankers'' that enable the user to see topic specific sub-feeds. Butterworth uses link prediction to infer the missing semantics between members of a user's social network in order to detect topical clusters embedded in the network structure. For automatically generated topic lists, Butterworth achieves an average top-10 precision of 78%, as compared to a time-ordered baseline of 45%. Next, I propose Dobby, a system for constructing a knowledge graph of user-defined keyword tags. Leveraging a sparse set of labeled edges, Dobby trains a supervised learning algorithm to infer the hypernym relationships between keyword tags. Dobby was evaluated by constructing a knowledge graph of LinkedIn's skills dataset, achieving an average precision of 85% on a set of human labeled hypernym edges between skills. Lastly, I propose Lobbyback, a system that automatically identifies clusters of documents that exhibit text reuse and generates ``prototypes'' that represent a canonical version of text shared between the documents. Lobbyback infers a network structure in a corpus of documents and uses community detection in order to extract the document clusters.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/133443/1/mattburg_1.pd
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