pattern learning
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Pattern Learning for Web Information Extraction
Justin Betteridge
IR Series SeminarMay 23, 2008
Tom Mitchell, Andrew CarlsonSue Ann Hong, Edith Law, Sophie Wang,
Estevam Hruschka
Outline
1. Web Information Extraction (WIE) 1.0
2. Contextual Patternsa. Definition
b. Assessment
c. Usage
3. Comparing Pattern Assessment Methods
4. WIE 2.0
WIE 1.0The Web
The Web
CheeseCheddar
Swiss
Gouda
WIE 1.0The Web
The Web
CheeseCheddar
Swiss
Gouda
__ such as __
such __ as __
… cheeses, including __ …
WIE 1.0The Web
The Web
Cheese
Cheddar
Swiss
Gouda
__ such as __
such __ as __
… cheeses, including __ …
Kraft manufactures a variety of cheeses, including Feta cheese.
Companies who market a variety of cheeses, including Kraft Foods, …
WIE 1.0The Web
The Web
Cheese
Cheddar
Swiss
Gouda
__ such as __
such __ as __
… cheeses, including __ …
Kraft manufactures a variety of cheeses, including Feta cheese.
Companies who market a variety of cheeses, including Kraft Foods, …
WIE 1.0The Web
The Web
Cheese
Cheddar
Swiss
Gouda
__ such as __
such __ as __
… cheeses, including __ …
Kraft manufactures a variety of cheeses, including Feta cheese.
Companies who market a variety of cheeses, including Kraft Foods, …
WIE 1.0The Web
The Web
Cheese
Cheddar
Swiss
Gouda
__ such as __
such __ as __
… cheeses, including __ …
Kraft manufactures a variety of cheeses, including Feta cheese.
Companies who market a variety of cheeses, including Kraft Foods, …
Feta
Kraft Foods
WIE 1.1The Web
The Web
Cheese
Cheddar cheeses such as __
Swiss cheeses, including __
Gouda
WIE 1.1The Web
The Web
Cheese
A slice of cheddar cheese goes well with …
Cheddar cheeses such as __
Swiss cheeses, including __
Gouda
WIE 1.1The Web
The Web
Cheese
A slice of cheddar cheese goes well with …
Cheddar cheeses such as __
Swiss cheeses, including __
Gouda
WIE 1.1The Web
The Web
Cheese
A slice of cheddar cheese goes well with …
Cheddar cheeses such as __
Swiss cheeses, including __
Gouda
a slice of __ cheese
__ goes well with
Dual Iterative Approach
1. Given seeds (instances and/or patterns)
2. Using instances, extract & assess candidate patterns
3. Using patterns, extract & assess candidate instances
4. Repeat
WIE 1.1The Web
The Web
Cheese
A slice of cheddar cheese goes well with …
Cheddar cheeses such as __
Swiss cheeses, including __
Gouda
a slice of __ cheese
__ goes well with
Assessing Instances
PMI:cheeses such as __ PMI:a slice of __
…
Cheese?NB classifier
Point-wise Mutual Information
score(choice) = log2(p(problem & choice) / (p(problem)p(choice)))
Turney, 2001
Patterns: FAQ
What does one look like?
How can I tell which ones are good?
What can I use them for?
Patterns Defined
mayo and a lot of cheddar cheese can make a sandwich yummy
Patterns Defined
mayo and a lot of cheddar cheese can make a sandwich yummy
... cheddar cheese soaked in brine
dairy products like cheddar cheese … NP Prep
VP Prep NP
Patterns Assessed
CheeseCheddar cheeses such as __
Swiss cheeses, including __
Gouda
a slice of __ cheese
__ goes well with
Patterns Assessed
CheeseCheddar cheeses such as __
Swiss cheeses, including __
Gouda
a slice of __ cheese
__ goes well with
H1: Must co-occur with at least 2 seed instancesH2: Sort by estimated precision
H1: Must co-occur with at least 2 seed instancesH2: Must not co-occur with any negative seed instances
H3: Must contain a trigger word
Patterns Assessed
CheeseCheddar cheeses such as __
Swiss cheeses, including __
Gouda
a slice of __ cheese
__ goes well with
H1: Must co-occur with at least 2 seed instancesH2: Sort by estimated precision
H1: Must co-occur with at least 2 seed instancesH2: Must not co-occur with any negative seed instances
H3: Must contain a trigger word
Etzioni et al, 2004
Talukdar et al, 2006
Patterns Assessed
PMI:cheddar PMI:swiss…
Cheese?NB classifier
Comparing Assessment Methods
Precision = portion of co-occuring NPs that are instances of the category
Recall = portion of instances that co-occur
Precision is more imporant (F0.5)
WIE 2.0
Category Discovery Relation Discovery
from patterns!! Continuous Learning
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