163,520 research outputs found
Provenance analysis for instagram photos
As a feasible device fingerprint, sensor pattern noise (SPN) has been proven to be effective in the provenance analysis of digital images. However, with the rise of social media, millions of images are being uploaded to and shared through social media sites every day. An image downloaded from social networks may have gone through a series of unknown image manipulations. Consequently, the trustworthiness of SPN has been challenged in the provenance analysis of the images downloaded from social media platforms. In this paper, we intend to investigate the effects of the pre-defined Instagram images filters on the SPN-based image provenance analysis. We identify two groups of filters that affect the SPN in quite different ways, with Group I consisting of the filters that severely attenuate the SPN and Group II consisting of the filters that well preserve the SPN in the images. We further propose a CNN-based classifier to perform filter-oriented image categorization, aiming to exclude the images manipulated by the filters in Group I and thus improve the reliability of the SPN-based provenance analysis. The results on about 20, 000 images and 18 filters are very promising, with an accuracy higher than 96% in differentiating the filters in Group I and Group II
Towards Egocentric Person Re-identification and Social Pattern Analysis
Wearable cameras capture a first-person view of the daily activities of the
camera wearer, offering a visual diary of the user behaviour. Detection of the
appearance of people the camera user interacts with for social interactions
analysis is of high interest. Generally speaking, social events, lifestyle and
health are highly correlated, but there is a lack of tools to monitor and
analyse them. We consider that egocentric vision provides a tool to obtain
information and understand users social interactions. We propose a model that
enables us to evaluate and visualize social traits obtained by analysing social
interactions appearance within egocentric photostreams. Given sets of
egocentric images, we detect the appearance of faces within the days of the
camera wearer, and rely on clustering algorithms to group their feature
descriptors in order to re-identify persons. Recurrence of detected faces
within photostreams allows us to shape an idea of the social pattern of
behaviour of the user. We validated our model over several weeks recorded by
different camera wearers. Our findings indicate that social profiles are
potentially useful for social behaviour interpretation
Two-layer classification and distinguished representations of users and documents for grouping and authorship identification
Most studies on authorship identification reported a drop in the identification result when the number of authors exceeds 20-25. In this paper, we introduce a new user representation to address this problem and split classification across two layers. There are at least 3 novelties in this paper. First, the two-layer approach allows applying authorship identification over larger number of authors (tested over 100 authors), and it is extendable. The authors are divided into groups that contain smaller number of authors. Given an anonymous document, the primary layer detects the group to which the document belongs. Then, the secondary layer determines the particular author inside the selected group. In order to extract the groups linking similar authors, clustering is applied over users rather than documents. Hence, the second novelty of this paper is introducing a new user representation that is different from document representation. Without the proposed user representation, the clustering over documents will result in documents of author(s) distributed over several clusters, instead of a single cluster membership for each author. Third, the extracted clusters are descriptive and meaningful of their users as the dimensions have psychological backgrounds. For authorship identification, the documents are labelled with the extracted groups and fed into machine learning to build classification models that predicts the group and author of a given document. The results show that the documents are highly correlated with the extracted corresponding groups, and the proposed model can be accurately trained to determine the group and the author identity
Measuring Social Unrest Based on Income Distribution
This paper develops a social unrest measure by revising Esteban-Ray (1994, Econometrica) polarization index. For the purpose of measuring more effectively the level of social unrest that is generated by separation of income classes, the new index allows for asymmetry between the rich and the poor groups' alienation feeling against the other, and it constructs a more effective group identification function. To facilitate statistical inferences, asymptotic distribution of the proposed measure is also derived using results from U-statistics, and an easy-to-implement jackknife-based variance estimation algorithm is obtained. Since the new index is general enough to include the Esteban-Ray index and the Gini index for group data as special cases, the asymptotic results can be readily applied to these popular indices. Evidence based on the Panel Study of Income Dynamics data suggests that the level of social unrest has generally increased over the sample period of 1981-2005, particular since the late 1990's, and the increase is statistically significant
A Semi-automatic Method for Efficient Detection of Stories on Social Media
Twitter has become one of the main sources of news for many people. As
real-world events and emergencies unfold, Twitter is abuzz with hundreds of
thousands of stories about the events. Some of these stories are harmless,
while others could potentially be life-saving or sources of malicious rumors.
Thus, it is critically important to be able to efficiently track stories that
spread on Twitter during these events. In this paper, we present a novel
semi-automatic tool that enables users to efficiently identify and track
stories about real-world events on Twitter. We ran a user study with 25
participants, demonstrating that compared to more conventional methods, our
tool can increase the speed and the accuracy with which users can track stories
about real-world events.Comment: ICWSM'16, May 17-20, Cologne, Germany. In Proceedings of the 10th
International AAAI Conference on Weblogs and Social Media (ICWSM 2016).
Cologne, German
Identification of Group Changes in Blogosphere
The paper addresses a problem of change identification in social group
evolution. A new SGCI method for discovering of stable groups was proposed and
compared with existing GED method. The experimental studies on a Polish
blogosphere service revealed that both methods are able to identify similar
evolution events even though both use different concepts. Some differences were
demonstrated as wellComment: The 2012 IEEE/ACM International Conference on Advances in Social
Networks Analysis and Mining, IEEE Computer Society, 2012, pp. 1233-123
Detection of Trending Topic Communities: Bridging Content Creators and Distributors
The rise of a trending topic on Twitter or Facebook leads to the temporal
emergence of a set of users currently interested in that topic. Given the
temporary nature of the links between these users, being able to dynamically
identify communities of users related to this trending topic would allow for a
rapid spread of information. Indeed, individual users inside a community might
receive recommendations of content generated by the other users, or the
community as a whole could receive group recommendations, with new content
related to that trending topic. In this paper, we tackle this challenge, by
identifying coherent topic-dependent user groups, linking those who generate
the content (creators) and those who spread this content, e.g., by
retweeting/reposting it (distributors). This is a novel problem on
group-to-group interactions in the context of recommender systems. Analysis on
real-world Twitter data compare our proposal with a baseline approach that
considers the retweeting activity, and validate it with standard metrics.
Results show the effectiveness of our approach to identify communities
interested in a topic where each includes content creators and content
distributors, facilitating users' interactions and the spread of new
information.Comment: 9 pages, 4 figures, 2 tables, Hypertext 2017 conferenc
Graph Theory and Networks in Biology
In this paper, we present a survey of the use of graph theoretical techniques
in Biology. In particular, we discuss recent work on identifying and modelling
the structure of bio-molecular networks, as well as the application of
centrality measures to interaction networks and research on the hierarchical
structure of such networks and network motifs. Work on the link between
structural network properties and dynamics is also described, with emphasis on
synchronization and disease propagation.Comment: 52 pages, 5 figures, Survey Pape
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