Grammars & Parsing
Inferring Team Task Plans from Human Meetings: A Generative Modeling Approach with Logic-Based Prior
Kim, Been, Chacha, Caleb M., Shah, Julie A.
We aim to reduce the burden of programming and deploying autonomous systems to work in concert with people in time-critical domains such as military field operations and disaster response. Deployment plans for these operations are frequently negotiated on-the-fly by teams of human planners. A human operator then translates the agreed-upon plan into machine instructions for the robots. We present an algorithm that reduces this translation burden by inferring the final plan from a processed form of the human team's planning conversation. Our hybrid approach combines probabilistic generative modeling with logical plan validation used to compute a highly structured prior over possible plans, enabling us to overcome the challenge of performing inference over a large solution space with only a small amount of noisy data from the team planning session. We validate the algorithm through human subject experimentations and show that it is able to infer a human team's final plan with 86% accuracy on average. We also describe a robot demonstration in which two people plan and execute a first-response collaborative task with a PR2 robot. To the best of our knowledge, this is the first work to integrate a logical planning technique within a generative model to perform plan inference.
Visual Commonsense for Scene Understanding Using Perception, Semantic Parsing and Reasoning
Aditya, Somak (Arizona State University) | Yang, Yezhou (University of Maryland, College Park) | Baral, Chitta (Arizona State University) | Fermuller, Cornelia (Associate Research Scientist, University of Maryland, College Park) | Aloimonos, Yiannis (University of Maryland, College Park)
In this paper we explore the use of visual common-sense knowledge and other kinds of knowledge (such as domain knowledge, background knowledge, linguistic knowledge) for scene understanding. In particular, we combine visual processing with techniques from natural language understanding (especially semantic parsing), common-sense reasoning and knowledge representation and reasoning to improve visual perception to reason about finer aspects of activities.
Latent Predicate Networks: Concept Learning with Probabilistic Context-Sensitive Grammars
Dechter, Eyal (Massachusetts Institute of Technology) | Rule, Joshua (Massachusetts Institute of Technology) | Tenenbaum, Joshua B. (Massachusetts Institute of Technology)
For humans, learning abstract concepts and learning languageย go hand in hand: we acquire abstract knowledge primarily throughย linguistic experience, and acquiring abstract concepts is a crucialย step in learning the meanings of linguistic expressions. Numberย knowledge is a case in point: we largely acquire concepts such asย seventy-three through linguistic means, and we can only know whatย the sentence ``seventy-three is more than twice as big asย thirty-one" means if we can grasp the meanings of its componentย number words. How do we begin to solve this problem? One approach isย to estimate the distribution from which sentences are drawn, and, inย doing so, infer the latent concepts and relationships that bestย explain those sentences. We present early work on a learningย framework called Latent Predicate Networks (LPNs) which learnsย concepts by inferring the parameters of probabilisticย context-sensitive grammars over sentences. ย We show that for a smallย fragment of sentences expressing relationships between Englishย number words, we can use hierarchical Bayesian inference to learnย grammars that can answer simple queries about previously unseenย relationships within this domain. These generalizations demonstrateย LPNs' promise as a tool for learning and representing conceptualย knowledge in language.
Detecting Rumor and Disinformation by Web Mining
Galitsky, Boris (Knowledge-Trail)
A method for determining whether given text is a rumor or disinformation is proposed, based on web mining and linguistic technology comparing two paragraphs of text. We hypothesize about a family of content generation algorithms which are capable of producing disinformation from a portion of genuine, original text. We then propose a disinformation detection algorithm which finds a candidate source of text on the web and compares it with the given text, applying parse thicket technology. Parse thicket is graph combined from a sequence of parse trees augmented with inter-sentence relations for anaphora and rhetoric structures. We evaluate our algorithm in the domain of customer reviews, considering a product review as an instance of possible disinformation. It is confirmed as a plausible way to detect rumor and disinformation in a web document. Linguistic approach presented here complements social network structure-based described on a corpus of research on disinformation detection.
Weakly-Supervised Grammar-Informed Bayesian CCG Parser Learning
Garrette, Dan (University of Texas at Austin) | Dyer, Chris (Carnegie Mellon University) | Baldridge, Jason (University of Texas at Austin) | Smith, Noah A. (Carnegie Mellon University)
Combinatory Categorial Grammar (CCG) is a lexicalized grammar formalism in which words are associated with categories that, in combination with a small universal set of rules, specify the syntactic configurations in which they may occur. Categories are selected from a large, recursively-defined set; this leads to high word-to-category ambiguity, which is one of the primary factors that make learning CCG parsers difficult, especially in the face of little data. Previous work has shown that learning sequence models for CCG tagging can be improved by using linguistically-motivated prior probability distributions over potential categories. We extend this approach to the task of learning a CCG parser from weak supervision. We present a Bayesian formulation for CCG parser induction that assumes only supervision in the form of an incomplete tag dictionary mapping some word types to sets of potential categories. Our approach outperforms a baseline model trained with uniform priors by exploiting universal, intrinsic properties of the CCG formalism to bias the model toward simpler, more cross-linguistically common categories.
Using Frame Semantics for Knowledge Extraction from Twitter
Sรธgaard, Anders (University of Copenhagen) | Plank, Barbara (University of Copenhagen) | Alonso, Hector Martinez (University of Copenhagen)
Knowledge bases have the potential to advance artificial intelligence, but often suffer from recall problems, i.e., lack of knowledge of new entities and relations. On the contrary, social media such as Twitter provide abundance of data, in a timely manner: information spreads at an incredible pace and is posted long before it makes it into more commonly used resources for knowledge extraction. In this paper we address the question whether we can exploit social media to extract new facts, which may at first seem like finding needles in haystacks. We collect tweets about 60 entities in Freebase and compare four methods to extract binary relation candidates, based on syntactic and semantic parsing and simple mechanism for factuality scoring. The extracted facts are manually evaluated in terms of their correctness and relevance for search. We show that moving from bottom-up syntactic or semantic dependency parsing formalisms to top-down frame-semantic processing improves the robustness of knowledge extraction, producing more intelligible fact candidates of better quality. In order to evaluate the quality of frame semantic parsing on Twitter intrinsically, we make a multiply frame-annotated dataset of tweets publicly available.
Word Segmentation for Chinese Novels
Qiu, Likun (Singapore University of Technology and Design) | Zhang, Yue (Singapore University of Technology and Design)
Word segmentation is a necessary first step for automatic syntactic analysis of Chinese text. Chinese segmentation is highly accurate on news data, but the accuracies drop significantly on other domains, such as science and literature. For scientific domains, a significant portion of out-of-vocabulary words are domain-specific terms, and therefore lexicons can be used to improve segmentation significantly. For the literature domain, however, there is not a fixed set of domain terms. For example, each novel can contain a specific set of person, organization and location names. We investigate a method for automatically mining common noun entities for each novel using information extraction techniques, and use the resulting entities to improve a state-of-the-art segmentation model for the novel. In particular, we design a novel double-propagation algorithm that mines noun entities together with common contextual patterns, and use them as plugin features to a model trained on the source domain. An advantage of our method is that no retraining for the segmentation model is needed for each novel, and hence it can be applied efficiently given the huge number of novels on the web.
Robot Learning Manipulation Action Plans by "Watching" Unconstrained Videos from the World Wide Web
Yang, Yezhou (University of Maryland College Park) | Li, Yi (NICTA, Australia) | Fermuller, Cornelia (University of Maryland) | Aloimonos, Yiannis (University of Maryland)
In order to advance action generation and creation in robots beyond simple learned schemas we need computational tools that allow us to automatically interpret and represent human actions. This paper presents a system that learns manipulation action plans by processing unconstrained videos from the World Wide Web. Its goal is to robustly generate the sequence of atomic actions of seen longer actions in video in order to acquire knowledge for robots. The lower level of the system consists of two convolutional neural network (CNN) based recognition modules, one for classifying the hand grasp type and the other for object recognition. The higher level is a probabilistic manipulation action grammar based parsing module that aims at generating visual sentences for robot manipulation. Experiments conducted on a publicly available unconstrained video dataset show that the system is able to learn manipulation actions by ``watching'' unconstrained videos with high accuracy.
Unsupervised Word Sense Disambiguation Using Markov Random Field and Dependency Parser
Chaplot, Devendra Singh (Samsung Electronics Co., Ltd.) | Bhattacharyya, Pushpak (IIT Bombay) | Paranjape, Ashwin (Stanford University)
Word Sense Disambiguation is a difficult problem to solve in the unsupervised setting. This is because in this setting inference becomes more dependent on the interplay between different senses in the context due to unavailability of learning resources. Using two basic ideas, sense dependency and selective dependency, we model the WSD problem as a Maximum A Posteriori (MAP) Inference Query on a Markov Random Field (MRF) built using WordNet and Link Parser or Stanford Parser. To the best of our knowledge this combination of dependency and MRF is novel, and our graph-based unsupervised WSD system beats state-of-the-art system on SensEval-2, SensEval-3 and SemEval-2007 English all-words datasets while being over 35 times faster.
Target-Dependent Churn Classification in Microblogs
Amiri, Hadi (University of Maryland) | III, Hal Daume (University of Maryland)
In particular, we investigate demographic business. Banks, telecommunication companies, airlines, Internet churn indicators (obtained from users of microposts), service providers, pay TV companies, and insurance content churn indicators (obtained from the textual firms etc., utilize customer churn or attrition rates as one of content of micro-posts), and context churn indicators (obtained their key business metrics. This metric is important as the from threads containing the micro-posts). We examine churn rate of a business is a good indicator of customer response factors that make this problem more challenging and investigate to services, pricing, and competitions. The ability to the performance of several state-of-the-art machine identify churny contents / behaviors can enable early intervention learning techniques on this problem. A challenging aspect processes (as part of retention campaigns) and ultimately of such classification task is that churny contents can be expressed a reduction in customer churn.