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Knowlywood: Mining Activity Knowledge From Hollywood Narratives

Despite the success of large knowledge bases, one kind of knowledge that has not received attention so far is that of human activities. An example of such an activity is proposing to someone (to get married). For the computer, knowing that this involves two adults, often but not necessarily a woman and a man, that it often takes place in some romantic location, that it typically involves flowers or jewelry, and that it is usually followed by kissing, is a valuable asset for tasks like natural language dialog, scene understanding, or video search. This corresponds to the challenging task of acquiring semantic frames that capture human activities, their participating agents, and their typical spatio-temporal contexts. This paper presents a novel approach that taps into movie scripts and other narrative texts. We develop a pipeline for semantic parsing and knowledge distillation, to systematically compile semantically refined activity frames. The resulting knowledge base contains hundreds of thousands of activity frames, mined from about two million scenes of movies, TV series, and novels. A manual assessment study, with extensive sampling and statistical significance tests, shows that the frames and their attribute values have an accuracy of at least 80 percent. We also demonstrate the usefulness of activity knowledge by the extrinsic use case of movie scene search.

Discriminative Link Prediction Using Local Links, Node Features and Community Structure

A link prediction (LP) algorithm is given a graph, and has to rank, for each node, other nodes that are candidates for new linkage. LP is strongly motivated by social search and recommendation applications. LP techniques often focus on global properties (graph conductance, hitting or commute times, Katz score) or local properties (Adamic-Adar and many variations, or node feature vectors), but rarely combine these signals. Furthermore, neither of these extremes exploit link densities at the intermediate level of communities. In this paper we describe a discriminative LP algorithm that exploits two new signals. First, a co-clustering algorithm provides community level link density estimates, which are used to qualify observed links with a surprise value. Second, links in the immediate neighborhood of the link to be predicted are interpreted %at face value, but through a local model of node feature similarities. These signals are combined into a discriminative link predictor. We evaluate the new predictor using five diverse data sets that are standard in the literature. We report on significant accuracy boosts compared to standard LP methods (including Adamic-Adar and random walk). Apart from the new predictor, another contribution is a rigorous protocol for benchmarking and reporting LP algorithms, which reveals the regions of strengths and weaknesses of all the predictors studied here, and establishes the new proposal as the most robust.

Local learning of item dissimilarity using content and link structure

In the Recommendation Problem, it is often important to find a set of items similar to a particular item or a group of items. This problem of finding similar items for the recommendation task may also be viewed as a link prediction problem in a network, where the items can be treated as the nodes. The strength of the edge connecting two items represents the similarity between the items. In this context, a central challenge is to suitably define an appropriate dissimilarity function between the items. For content based recommender systems, the dissimilarity function should take into account the individual attributes of the items. The same attribute may have different importances in different parts of the underlying network. We focus on the problem of learning a suitable dissimilarity function between items and address it by formulating it as a constrained optimization problem which captures the local weightages of the attributes in different regions of the graph. The constraints are imposed in such a way that the non-connected nodes show higher value of dissimilarity than the connected nodes. The local tuning of the weights learns the optimal value of weights in various parts of the network: from the portions having rich graph information to the portions having only content information. Detailed experimentation shows the superiority of the proposed algorithm over the Adamic Adar metric as well as logistic regression methodology.

Lights, Camera, Action: Knowledge Extraction from Movie Scripts

With the success of large knowledge graphs, research on automatically acquiring commonsense knowledge is revived. One kind of knowledge that has not received attention is that of human activities. This paper presents an information extraction pipeline for systematically distilling activity knowledge from a corpus of movie scripts. Our semantic frames capture activities together with their participating agents and their typical spatial, temporal and sequential contexts. The resulting knowledge base comprises about 250,000 activities with links to specific movie scenes where they occur.

Root locus method for any fractional order commensurate system

Fractional order calculus has attracted interests of many control scientists in the last two decades as it more accurately explains the dynamics of the known field like analysis of feedback amplifier, fractances etc. In this paper we have presented a systematic and complete approach to draw the root locus of any closed loop fractional order LTI commensurate system whose open loop transfer function has complex pole and/or complex zeros. Analogous to the integer order system, we have developed a step by step algorithm( viz. asymptotes, break away and break in points, arrival and departure angle etc.)to draw the root loci of denominator of closed loop system transfer function. Finally we have explained the inference of stability of the closed loop system from the root loci of the system in the first Riemann sheet.

LMPP: A Large Margin Point Process Combining Reinforcement and Competition for Modeling Hashtag Popularity

Predicting the popularity dynamics of Twitter hashtags has a broad spectrum of applications. Existing works have primarily focused on modeling the popularity of individual tweets rather than the underlying hashtags. As a result, they fail to consider several realistic factors contributing to hashtag popularity. In this paper, we propose Large Margin Point Process (LMPP), a probabilistic framework that integrates hashtag-tweet influence and hashtaghashtag competitions, the two factors which play important roles in hashtag propagation. Furthermore, while considering the hashtag competitions, LMPP looks into the variations of popularity rankings of the competing hashtags across time. Extensive experiments on seven real datasets demonstrate that LMPP outperforms existing popularity prediction approaches by a significant margin. Additionally, LMPP can accurately predict the relative rankings of competing hashtags, offering additional advantage over the state-of-the-art baselines.

Discriminative Link Prediction using Local, Community, and Global Signals

Predicting plausible links that may emerge between pairs of nodes is an important task in social network analysis, with over a decade of active research. Here, we propose a novel framework for link prediction. It integrates signals from node features, the existing local link neighborhood of a node pair, community-level link density, and global graph properties. Our framework uses a stacked two-level learning paradigm. At the lower level, the first two kinds of features are processed by a novel local learner. Its outputs are then integrated with the last two kinds of features by a conventional discriminative learner at the upper-level. We also propose a new stratified sampling scheme for evaluating link prediction algorithms in the face of an extremely large number of potential edges, out of which very few will ever materialize. It is not tied to a specific application of link prediction, but robust to a range of application requirements. We report on extensive experiments with seven benchmark datasets and over five competitive baseline systems. The system we present consistently shows at least 10 percent accuracy improvement over state-of-the-art, and over 30 percent improvement in some cases. We also demonstrate, through ablation, that our features are complementary in terms of the signals and accuracy benefits they provide.

Demarcating Endogenous and Exogenous Opinion Diffusion Process on Social Networks

The networked opinion diffusion in online social networks (OSN) is governed by the two genres of opinions-endogenous opinions that are driven by the influence of social contacts between users, and exogenous opinions which are formed by external effects like news, feeds etc. Such duplex opinion dynamics is led by users belonging to two categories- organic users who generally post endogenous opinions and extrinsic users who are susceptible to externalities, and mostly post the exogenous messages. Precise demarcation of endogenous and exogenous messages offers an important cue to opinion modeling, thereby enhancing its predictive performance. On the other hand, accurate user selection aids to detect extrinsic users, which in turn helps in opinion shaping. In this paper, we design CherryPick, a novel learning machinery that classifies the opinions and users by solving a joint inference task in message and user set, from a temporal stream of sentiment messages. Furthermore, we validate the efficacy of our proposal from both modeling and shaping perspectives. Moreover, for the latter, we formulate the opinion shaping problem in a novel framework of stochastic optimal control, in which the selected extrinsic users optimally post exogenous messages so as to guide the opinions of others in a desired way. On five datasets crawled from Twitter, CherryPick offers a significant accuracy boost in terms of opinion forecasting, against several competitors. Furthermore, it can precisely determine the quality of a set of control users, which together with the proposed online shaping strategy, consistently steers the opinion dynamics more effectively than several state-of-the-art baselines.