Greedy Inference Algorithms for Structured and Neural Models

dc.contributor.authorSun, Qingen
dc.contributor.committeechairBatra, Dhruven
dc.contributor.committeechairHuang, Jia-Binen
dc.contributor.committeememberAbbott, A. Lynnen
dc.contributor.committeememberParikh, Devien
dc.contributor.committeememberPrakash, B. Adityaen
dc.contributor.committeememberDhillon, Harpreet Singhen
dc.contributor.departmentElectrical Engineeringen
dc.date.accessioned2018-01-19T09:00:37Zen
dc.date.available2018-01-19T09:00:37Zen
dc.date.issued2018-01-18en
dc.description.abstractA number of problems in Computer Vision, Natural Language Processing, and Machine Learning produce structured outputs in high-dimensional space, which makes searching for the global optimal solution extremely expensive. Thus, greedy algorithms, making trade-offs between precision and efficiency, are widely used. Unfortunately, they in general lack theoretical guarantees. In this thesis, we prove that greedy algorithms are effective and efficient to search for multiple top-scoring hypotheses from structured (neural) models: 1) Entropy estimation. We aim to find deterministic samples that are representative of Gibbs distribution via a greedy strategy. 2) Searching for a set of diverse and high-quality bounding boxes. We formulate this problem as the constrained maximization of a monotonic sub-modular function such that there exists a greedy algorithm having near-optimal guarantee. 3) Fill-in-the-blank. The goal is to generate missing words conditioned on context given an image. We extend Beam Search, a greedy algorithm applicable on unidirectional expansion, to bidirectional neural models when both past and future information have to be considered. We test our proposed approaches on a series of Computer Vision and Natural Language Processing benchmarks and show that they are effective and efficient.en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:13673en
dc.identifier.urihttp://hdl.handle.net/10919/81860en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectgreedy algorithmen
dc.subjectnatural language processingen
dc.subjectgraph modelsen
dc.subjectrecurrent neural networksen
dc.subjectbeam searchen
dc.titleGreedy Inference Algorithms for Structured and Neural Modelsen
dc.typeDissertationen
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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