Filtering out noisy sentences of an answer which are irrelevant to the question being asked increases the utility and reuse of a Question-Answer (QA) repository. Filtering such sentences might be difficult for traditional supervised classification methods due to the extensive labelling efforts involved. In this paper, we propose a semi-supervised learning approach, where we first infer a set of topics on the corpus using Latent Dirichlet Allocation (LDA). We label the topics automatically using a small labelled set and use them for classifying an unseen sentence as useful or noisy. We performed the experiments on a real-life help desk dataset and find that the results are comparable to other methods in semi-supervised learning.

Bribery in elections is an important problem in computational social choice theory. We introduce and study two important special cases of the bribery problem, namely, FRUGAL-BRIBERY and FRUGAL-$BRIBERY where the briber is frugal in nature. By this, we mean that the briber is only able to influence voters who benefit from the suggestion of the briber. More formally, a voter is vulnerable if the outcome of the election improves according to her own preference when she accepts the suggestion of the briber. In the FRUGAL-BRIBERY problem, the goal is to make a certain candidate win the election by changing only the vulnerable votes. In the FRUGAL-$BRIBERY problem, the vulnerable votes have prices and the goal is to make a certain candidate win the election by changing only the vulnerable votes, subject to a budget constraint. We show that both the FRUGAL-BRIBERY and the FRUGAL-$BRIBERY problems are intractable for many commonly used voting rules for weighted as well as unweighted elections. These intractability results demonstrate that bribery is a hard computational problem, in the sense that several special cases of this problem continue to be computationally intractable. This strengthens the view that bribery, although a possible attack on an election in principle, may be infeasible in practice.

We propose a learning agent that first learns concepts in an integrated, cross-modal manner, and then uses these as the semantics model to map language. We consider an abstract model for the action of throwing, modeling the entire trajectory. From a large set of throws, we take the trajectory images and and the throwing parameters. These are mapped jointly onto a low-dimensional non-linear manifold. Such models improve with practice, and can be used as the starting point for real-life tasks such as aiming darts or recognizing throws by others. How can such models can be used in learning language? We consider a set of videos involving throwing and rolling actions. These actions are analyzed into a set of contrastive semantic classes based on agent, action, and the thrown object (trajector). We obtain crowdsourced commentaries for these videos (raw text) from a number of adults. The learner attempts to associate labels using contrastive probabilities for the semantic class. Only a handful of high-confidence words are found, but the agent starts off with this partial knowledge. These are used to learn incrementally larger syntactic patterns, initially for the trajector, and eventually for full agent-trajector-action sentences. We demonstrate how this may work for two completely different languages - English and Hindi, and also show how rudiments of agreement, synonymy and polysemy are detected.

Human wayfinding operates very very differently from traditional deterministic algorithms owing to a) restrictions in working memory resulting in subjective regionalized maps, and b)flexible adoption of different navigation strategies. While a number of cognitive strategies have been proposed for human wayfinding, these have been hard to evaluate thoroughly owing to a lack of computational simulation. In this work, we propose a stochastic approach for capturing these aspects, and argue for a memoryless, stationary implementation. In two longitudinal experiments on the same group of subjects, we first estimate the subjective regionalized maps for each subject on the same familiar spatial domain. Later, based on their wayfinding responses, we can estimate the stationary probabilities for different strategies. We apply this algorithm to evaluate three wayfinding strategies proposed in the literature, and repudiate the previously held suggestion that they are followed equiprobably.

Presentations are one of the most common and effective ways of communicating the overview of a work to the audience. Given a technical paper, automatic generation of presentation slides reduces the effort of the presenter and helps in creating a structured summary of the paper. In this paper, we propose the framework of a novel system that does this task. Any paper that has an abstract and whose sections can be categorized under introduction, related work, model, experiments and conclusions can be given as input. As documents in LaTeX are rich in structural and semantic information we used them as input to our system. These documents are initially converted to XML format. This XML file is parsed and information in it is extracted. A query specific extractive summarizer has been used to generate slides. All graphical elements from the paper are made well use of by placing them at appropriate locations in the slides. These slides are presented in the document order.