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You searched for subject:(parzen window). Showing records 1 – 2 of 2 total matches.

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Rochester Institute of Technology

1. Hu, Lei. Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions.

Degree: PhD, 2016, Rochester Institute of Technology

Math expressions are an essential part of scientific documents. Handwritten math expressions recognition can benefit human-computer interaction especially in the education domain and is a critical part of document recognition and analysis. Parsing the spatial arrangement of symbols is an essential part of math expression recognition. A variety of parsing techniques have been developed during the past three decades, and fall into two groups. The first group is graph-based parsing. It selects a path or sub-graph which obeys some rule to form a possible interpretation for the given expression. The second group is grammar driven parsing. Grammars and related parameters are defined manually for different tasks. The time complexity of these two groups parsing is high, and they often impose some strict constraints to reduce the computation. The aim of this thesis is working towards building a straightforward and effective parser with as few constraints as possible. First, we propose using a line of sight graph for representing the layout of strokes and symbols in math expressions. It achieves higher F-score than other graph representations and reduces search space for parsing. Second, we modify the shape context feature with Parzen window density estimation. This feature set works well for symbol segmentation, symbol classification and symbol layout analysis. We get a higher symbol segmentation F-score than other systems on CROHME 2014 dataset. Finally, we develop a Maximum Spanning Tree (MST) based parser using Edmonds' algorithm, which extracts an MST from the directed line of sight graph in two passes: first symbols are segmented, and then symbols and spatial relationship are labeled. The time complexity of our MST-based parsing is lower than the time complexity of CYK parsing with context-free grammars. Also, our MST-based parsing obtains higher structure rate and expression rate than CYK parsing when symbol segmentation is accurate. Correct structure means we get the structure of the symbol layout tree correct, even though the label of the edge in the symbol layout tree might be wrong. The performance of our math expression recognition system with MST-based parsing is competitive on CROHME 2012 and 2014 datasets. For future work, how to incorporate symbol classifier result and correct segmentation error in MST-based parsing needs more research. Advisors/Committee Members: Richard Zanibbi, Nathan Cahill, Harold Mouchere.

Subjects/Keywords: Graph representation; Handwritten math expressions recognition; Line of sight graph; MST-based parsing; Parzen window shape context feature; Symbol segmentation

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APA (6th Edition):

Hu, L. (2016). Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions. (Doctoral Dissertation). Rochester Institute of Technology. Retrieved from https://scholarworks.rit.edu/theses/9042

Chicago Manual of Style (16th Edition):

Hu, Lei. “Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions.” 2016. Doctoral Dissertation, Rochester Institute of Technology. Accessed May 24, 2019. https://scholarworks.rit.edu/theses/9042.

MLA Handbook (7th Edition):

Hu, Lei. “Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions.” 2016. Web. 24 May 2019.

Vancouver:

Hu L. Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions. [Internet] [Doctoral dissertation]. Rochester Institute of Technology; 2016. [cited 2019 May 24]. Available from: https://scholarworks.rit.edu/theses/9042.

Council of Science Editors:

Hu L. Features and Algorithms for Visual Parsing of Handwritten Mathematical Expressions. [Doctoral Dissertation]. Rochester Institute of Technology; 2016. Available from: https://scholarworks.rit.edu/theses/9042


Virginia Tech

2. Gardner, Robert Matthew. A Wide-Area Perspective on Power System Operation and Dynamics.

Degree: PhD, Electrical and Computer Engineering, 2008, Virginia Tech

Classically, wide-area synchronized power system monitoring has been an expensive task requiring significant investment in utility communications infrastructures for the service of relatively few costly sensors. The purpose of this research is to demonstrate the viability of power system monitoring from very low voltage levels (120 V). Challenging the accepted norms in power system monitoring, the document will present the use of inexpensive GPS time synchronized sensors in mass numbers at the distribution level. In the past, such low level monitoring has been overlooked due to a perceived imbalance between the required investment and the usefulness of the resulting deluge of information. However, distribution level monitoring offers several advantages over bulk transmission system monitoring. First, practically everyone with access to electricity also has a measurement port into the electric power system. Second, internet access and GPS availability have become pedestrian commodities providing a communications and synchronization infrastructure for the transmission of low-voltage measurements. Third, these ubiquitous measurement points exist in an interconnected fashion irrespective of utility boundaries. This work offers insight into which parameters are meaningful to monitor at the distribution level and provides applications that add unprecedented value to the data extracted from this level. System models comprising the entire Eastern Interconnection are exploited in conjunction with a bounty of distribution level measurement data for the development of wide-area disturbance detection, classification, analysis, and location routines. The main contributions of this work are fivefold: the introduction of a novel power system disturbance detection algorithm; the development of a power system oscillation damping analysis methodology; the development of several parametric and non-parametric power system disturbance location methods, new methods of power system phenomena visualization, and the proposal and mapping of an online power system event reporting scheme. Advisors/Committee Members: Liu, Yilu (committeechair), Abbott, A. Lynn (committee member), Mili, Lamine M. (committee member), Thorp, James S. (committee member), Russell, David L. (committee member).

Subjects/Keywords: TDOA; FNET; FDR; GPS; Wide-Area monitoring; wide-area measurements; power system event; power system; load shedding; generation trip; eastern interconnection; wams; ems; nerc; ercot; wecc; parzen window; interconnection islanding; PMU; half-plane method; least squares; event trigger; generation-load mismatch; electromechanical wave; wave propagation; time delay of arrival; oscillation trigger; modal analysis; electric grid; transmission network; transmission system; hypocenter; frequency; matrix pencil; mahalanobis distance

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gardner, R. M. (2008). A Wide-Area Perspective on Power System Operation and Dynamics. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/26779

Chicago Manual of Style (16th Edition):

Gardner, Robert Matthew. “A Wide-Area Perspective on Power System Operation and Dynamics.” 2008. Doctoral Dissertation, Virginia Tech. Accessed May 24, 2019. http://hdl.handle.net/10919/26779.

MLA Handbook (7th Edition):

Gardner, Robert Matthew. “A Wide-Area Perspective on Power System Operation and Dynamics.” 2008. Web. 24 May 2019.

Vancouver:

Gardner RM. A Wide-Area Perspective on Power System Operation and Dynamics. [Internet] [Doctoral dissertation]. Virginia Tech; 2008. [cited 2019 May 24]. Available from: http://hdl.handle.net/10919/26779.

Council of Science Editors:

Gardner RM. A Wide-Area Perspective on Power System Operation and Dynamics. [Doctoral Dissertation]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/26779

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