The cognitive antagonism is one of the core aspects in electromagnetic spectrum warfare. Since it is impossible for the opposing parties to perceive the state information of each other completely, the existing evaluation methods are inappropriate for evaluating the cognitive antagonistic effectiveness. For solving this problem, a Stackelberg game-based method of modeling the cognitive antagonism with incomplete information is proposed in this article, i.e., depending on the domain knowledge and public information, we first tease out the antijamming measures of radars and then propose the empirical formulas of antijamming improve factors accordingly. Similarly, the method to calculate the jamming payoff is proposed for the power suppression and spoofing patterns of jammers. Furthermore, the method of constructing the strategy matrices for bimatrix Stackelberg game is presented. By taking the probability of radar recognizing false targets as uncertain information, we test the effect of game in a specified antagonistic environment and draw out some useful conclusions from the testing results.

Recent studies have demonstrated inspiring success in leveraging geo-tagged social media data for applications such as event detection, location recommendation and mobile healthcare. However, in most real-life social media streams, only a small percentage of data have explicit geo-location metadata, which hinders the power of social media from being fully unleashed. We study the problem of inferring geo-locations from social media messages. While a number of text-based geo-locating techniques have been proposed, they either fall short of automatically identifying indicative keywords from noisy social media posts or do not integrate rich prior knowledge of geological regions. We propose an attentive memory network called GeoAttn for localization of social media messages. To capture indicative keywords for location inference, GeoAttn consists of an attentive message encoder, which selectively focuses on location-indicative terms to derive a discriminative message representation. The message embedding is then fed into a memory network, which selectively attends to relevant Points-of-Interest (POIs) for location prediction. The message encoder and key-value memory network are jointly trained in an end-to-end manner. The attention mechanisms in GeoAttn not only alleviate noisy information for higher prediction accuracy, but also provide interpretable attention scores that rationalize the predictions. Our experiments on a million-scale geo-tagged tweet dataset show that GeoAttn outperforms previous state-of-the-art location prediction methods by 15.5% in mean error distance, and is capable of locating over half of the tweets within 5km.

Taxonomies are of great value to many knowledge-rich applications. As the manual taxonomy curation costs enormous human effects, automatic taxonomy construction is in great demand. However, most existing automatic taxonomy construction methods can only build hypernymy taxonomies wherein each edge is limited to expressing the is-a relation. Such a restriction limits their applicability to more diverse real-world tasks where the parent-child may carry different relations. In this paper, we aim to construct a task-guided taxonomy from a domain-specific corpus, and allow users to input a seed taxonomy, serving as the task guidance. We propose an expansion-based taxonomy construction framework, namely HiExpan, which automatically generates key term list from the corpus and iteratively grows the seed taxonomy. Specifically, HiExpan views all children under each taxonomy node forming a coherent set and builds the taxonomy by recursively expanding all these sets. Furthermore, HiExpan incorporates a weakly-supervised relation extraction module to extract the initial children of a newly-expanded node and adjusts the taxonomy tree by optimizing its global structure. Our experiments on three real datasets from different domains demonstrate the effectiveness of HiExpan for building task-guided taxonomies.

The real-time discovery of local events (e.g., protests, disasters) has been widely recognized as a fundamental socioeconomic task. Recent studies have demonstrated that the geo-tagged tweet stream serves as an unprecedentedly valuable source for local event detection. Nevertheless, how to effectively extract local events from massive geo-tagged tweet streams in real time remains challenging. To bridge the gap, we propose a method for effective and real-time local event detection from geo-tagged tweet streams. Our method, named G eo B urst+ , first leverages a novel cross-modal authority measure to identify several pivots in the query window. Such pivots reveal different geo-topical activities and naturally attract similar tweets to form candidate events. G eo B urst+ further summarizes the continuous stream and compares the candidates against the historical summaries to pinpoint truly interesting local events. Better still, as the query window shifts, G eo B urst+ is capable of updating the event list with little time cost, thus achieving continuous monitoring of the stream. We used crowdsourcing to evaluate G eo B urst+ on two million-scale datasets and found it significantly more effective than existing methods while being orders of magnitude faster.

Detecting local events (e.g., protest, disaster) at their onsets is an important task for a wide spectrum of applications, ranging from disaster control to crime monitoring and place recommendation. Recent years have witnessed growing interest in leveraging geo-tagged tweet streams for online local event detection. Nevertheless, the accuracies of existing methods still remain unsatisfactory for building reliable local event detection systems. We propose TrioVecEvent, a method that leverages multimodal embeddings to achieve accurate online local event detection. The effectiveness of TrioVecEvent is underpinned by its two-step detection scheme. First, it ensures a high coverage of the underlying local events by dividing the tweets in the query window into coherent geo-topic clusters. To generate quality geo-topic clusters, we capture short-text semantics by learning multimodal embeddings of the location, time, and text, and then perform online clustering with a novel Bayesian mixture model. Second, TrioVecEvent considers the geo-topic clusters as candidate events and extracts a set of features for classifying the candidates. Leveraging the multimodal embeddings as background knowledge, we introduce discriminative features that can well characterize local events, which enables pinpointing true local events from the candidate pool with a small amount of training data. We have used crowdsourcing to evaluate TrioVecEvent, and found that it improves the performance of the state-of-the-art method by a large margin.