Along with the development of Information Technology, Online Social Networks (OSN) are constantly developing and have become popular media in the world. Besides communication enhancement benefits, OSN have such limitations on rapid spread of false information as rumors, fake news, and contradictory news. False information spread is collectively referred to as misinformation which has significant on social communities. The more sources and topics of misinformation are, the greater the number of users are affected. Therefore, it is necessary to prevent the spread of misinformation with multiple topics within a given period of time. In this paper, we propose a Multiple Topics Linear Threshold model for misinformation diffusion, and define a misinformation blocking problem based on this model that takes account of multiple topics and budget constraint. The problem is to find a set of nodes that minimizes the impact of misinformation at an allowed cost when blocking them from the network. We prove that the problem is NP-hard and the time complexity of the objective function calculation is #P-hard. We also prove that the objective function is monotone and submodular. We propose an approximation algorithm with approximation ratio (1 − 1/ √ e) based on these attributes. For large networks, we propose an extended algorithm by using a tree data structure for quickly updating and calculating the objective function. Experiments conducted on real-world datasets show efficiency and effectiveness of our proposed algorithms in comparison with other state-of-the-art algorithms.
The research leading to these results received funding from the Czech Ministry of Education, Youth and Sports under grant No. SP2020/65 conducted at VSB-Technical University of Ostrava.
Abstract. Recently a lot of progress has been made in rumor modeling and rumor detection for micro-blogging streams. However, existing automated methods do not perform very well for early rumor detection, which is crucial in many settings, e.g., in crisis situations. One reason for this is that aggregated rumor features such as propagation features, which work well on the long run, are -due to their accumulating characteristic -not very helpful in the early phase of a rumor. In this work, we present an approach for early rumor detection, which leverages Convolutional Neural Networks for learning the hidden representations of individual rumor-related tweets to gain insights on the credibility of each tweets. We then aggregate the predictions from the very beginning of a rumor to obtain the overall event credits (so-called wisdom), and finally combine it with a time series based rumor classification model. Our extensive experiments show a clearly improved classification performance within the critical very first hours of a rumor. For a better understanding, we also conduct an extensive feature evaluation that emphasized on the early stage and shows that the low-level credibility has best predictability at all phases of the rumor lifetime.
In many cases, a user turns to search engines to find information about real-world situations, namely, political elections, sport competitions, or natural disasters. Such temporal querying behavior can be observed through a significant number of event-related queries generated in web search. In this paper, we study the task of detecting event-related queries, which is the first step for understanding temporal query intent and enabling different temporal search applications, e.g., time-aware query auto-completion, temporal ranking, and result diversification. We propose a two-step approach to detecting events from query logs. We first identify a set of event candidates by considering both implicit and explicit temporal information needs. The next step further classifies the candidates into two main categories, namely, event or non-event. In more detail, we leverage different machine learning techniques for query classification, which are trained using the feature set composed of time series features from signal processing, along with features derived from click-through information, and standard statistical features. In order to evaluate our proposed approach, we conduct an experiment using two real-world query logs with manually annotated relevance assessments for 837 events. To this end, we provide a large set of eventrelated queries made available for fostering research on this challenging task.
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