Online Books:
java.net on MarkMail:
Search |
||
Notes from Thursday Semantic Technology ConferencePosted by haroldcarr on June 18, 2009 at 3:11 PM PDT
Here are my notes from Thursday at www.semantic-conference.com
==============================================================================
Thursday, 6/18/2009
Conference Attendance: 1170
------------------------------------------------------------------------------
Keynote General Session 8:30AM - 09:30AM
Semantics at The New York Times
Larson, Robert, New York Times Company
Sandhaus, Evan, New York Times Company
Conners, Christine, moderator
Business / Non-Technical
Publishing
What the Times means by Semantics
- Any tool that discovers/leverages metadata to
make content more accessible
The Morgue
- File cabinets of clippings, photos,... of Times and other papers
- Reporter seeking info on story would go to morgue and search
The New York TImes Index
- Where info can be found in printed version
NYTimex.com
- MS Word -> Newspaper CMS -> tagging software -> web cms
reporters editors section, pagen
links byline newsdesk
type
biographic
- Topic pages
Aggregate from NYT and other locations
Future
- Improve workflow
- Digitize 5 million photos from morgue
- tag NYT blogs
- Tag user content
- Allow users to tag
Times APIs
- Times Tag
- Article Search API
New York Times Annotated Corpus
- DVD of every article+metadata 1987-2007
- corpus.nytimes.com
- non-commerical: $300
------------------------------------------------------------------------------
Conference Sessions 9:45AM - 10:45AM
Visualizing RDF
Franz - Gruff
Kieth Sutton - silvafug.org - Silicon Valley Flex User Group
www.diagramic.com
EX: www.forbes20.com, www.diagramic.com/v/?p=google
FlexParts (Adobe AIR application)
- Visualizing Freebase data
SEED FOR NEXT YEAR'S CONFERENCE:
- Visualizing RDF with JavaFX
------------------------------------------------------------------------------
Conference Sessions 11:00AM - 12:00PM
--------------------------------------------------
SQUIN
squin.org
query the web of linked data
Uses SINDICE
EX usage: turn2live.com
--------------------------------------------------
Practical OWL 2 RL Reasoning Via Fast Forward Chaining Inference Engines
Matheus, Christopher John, VIStology, Inc.
Technology - Intermediate
Foundational Topics
OWL 2 RL
- Implemented by rule-based forward chaining inference engines
- Implemented as collection of 75+ implication and consistency rules
Unsupported/Restrictions
- owl:cardinality, owl:minCardinality
- owl:qualifiedCardinality owl:qualifiedMinCardinality
- owl:DisjointUnion
- owl:ReflexiveObjectProperty
- owl:topObjectProperty, owl:bottomDatatypeProperty
- owl:topDataProperty, owl:bottomDataProperty
- xsd:real, wsd:rational
- URI cannot be both a class and an individual
- owl:maxCardinality restricted to 0 & 1
- Data ranges restricted to sxd datatypes and intersection of them
- Axioms designed to avoid inferring existence of individuals
not explicitly mention in knowledge base
- Does not include axiomatic triples (but impls may include them)
(e.g., characteristics of elements of the language)
Types of inferencing
- Entailment
- Classification (entailment of rdf:type facts)
- Consistency checking
P rdfs:domain C
I P V
-----
I rdf:type C
(just by giving I property P then you can infer its type)
B rdfs:subClassOf A
I rdf:type B
------------
I rdf:type A
parentOf owl:inverseOf childOf
John parentOf Diana
------------------
Diana childOf John
C owl:hasValue V
C owl:onProperty P
I rdf:type C
------------
I P V
C owl:hasValue V
C owl:onProperty P
I rdf:type C
------------
I rdf:type C
C1 owl:disjointWith C2
I rdf:type C1
I rdf:type C2
--------------
INCONSISTENCY
--------------------------------------------------
Ideas for Future Semantic Applications
Sarris, Tony, Unisys Corporation - Systems & Technology
Sweeney, Peter, Primal Fusion
Business / Non-Technical
Business & Marketplace
PrimalFusion
------------------------------------------------------------------------------
Product Seminars/Field Trips 1:00PM - 5:00PM
--------------------------------------------------
A Programmer's Introduction to Pellet: How to Build Ontology-based Semantic Applications
Sirin, Evren, Clark & Parsia LLC
Smith, Michael A, Clark & Parsia LLC
Technology - Advanced
Semantic Applications
clarkparsia.com/pellet/tutorial
What is Pellet?
- OWL-DL reasoner
- Supports nearly all of OWL 1 and OWL 2
- Sound and complete reasoner
- Written in Java and available from http://clarkparsia.com/pellet
Talk Coverage
- Introduction to reasoning with Pellet
Basic reasoning concepts
Using Pellet from command-line
- Programming with Pellet
Available APIs and usage
Reasoning and query answering
Explaining inferences
- Advanced Pellet features
Closed-world data validation with Integrity Constraints
Running Example: POPS
- Expertise location in a large organization
Based on POPS application in NASA
Multiple sources containing personnel data: contact
information, work history, evidence of skills,
publications, etc.
Find people that satisfy certain conditions
- Several challenges
Integrate data from multiple sources
Ensure data consistency
Query with inferencing
User interface (not covered in this talk; see jSpace)
Demo of JSpace/POPS
Building the Example
- Author ontology schemas
Validate and debug schema definitions
- Connect multiple schemas
Simple ontology alignment
- Validating instance data
Identify and resolve inconsistencies in the data
Closed world data validation with Pellet Integrity
Constraints
- Reasoning with instance data
Answer queries over combined data using Pellet
Scalability and performance considerations
OWL in 3 Slides (1) - ENTITIES
- Class: Person, Organization, Project, Skill, ...
- Datatype: string, integer, date, ...
- Individual: Evren, C&P, POPS, ...
- Literal: "Evren Sirin", 5, 5/26/2008, ...
- Object Property: worksAt, hasSkill, ...
- Data property: name, proficiencyLevel, ...
OWL in 3 Slides (2) - EXPRESSIONS
- Class expressions
and, or, not
some, only, min, max, exactly, value, Self
{ ... }
- Datatype definitions
and, or, not
<, <=, >, >=
{ ... }
OWL in 3 Slides (3) - AXIOMS
- Class axioms
subClassOf, equivalentTo, disjointWith
- Property axioms
subPropertyOf, equivalentTo, inverseOf,
disjointWith, subPropertyChain, domain, range
- Property characteristics
Functional, InverseFunctional, Transitive,
Symmetric, Asymmetric, Reflexive, Irreflexive
- Individual assertions
Class assertion, property assertion, sameAs,
differentFrom
Reasoning in OWL
1. Check the consistency of a set of axioms
Verify the input axioms do not contain contradictions
Mandatory first step before any other reasoning service
Fix the inconsistency before reasoning
Any consequence can be inferred from inconsistency
2. Infer new axioms from a set of axioms
Truth of an axiom is logically proven from asserted axioms
Infinitely many inferences for any non-empty ontology
Inferences can be computed as a batch process or as
required by queries
Classification
- build tree of subClass relationships
Realization
- assign individuals to their most specific class membership
Protege 4 does not come with Pellet built in
- A plugin is available
- Use protege "check for plugins"
»
Comments
Comments are listed in date ascending order (oldest first)
|
||
|
|