IST 511 Information Management: Information
and Technology
Information extraction, data mining, metadata
Dr. C. Lee Giles
David Reese Professor, College of Information Sciences
and Technology
The Pennsylvania State University, University Park, PA,
USA
giles@ist.psu.edu
http://clgiles.ist.psu.edu
Special thanks to E. Agichtein, K. Borne, S. Sarawagi, C. Lagoze,
Last time
What are probabilities
What is information theory
What is probabilistic reasoning
–
–
–
–
Definitions
Why important
How used – decision making
Decision trees
Impact on information science
Today
What is information extraction
What is data mining
– Text mining as subfield
What is metadata
Impact on information science
Tomorrow
Topics used in IST
• Digital libraries,
• Scientometrics, bibliometrics
• Digital humanities
Theories in Information Sciences
Enumerate some of these theories in this course.
Issues:
– Unified theory?
– Domain of applicability
– Conflicts
Theories here are
– Very algorithmic
– Some quantitative
– Some qualitative
Quality of theories
–
–
–
–
Occam’s razor
Subsumption of other theories (all can use machine learning)
Text mining special case of data mining
Natural language processing uses data mining methods
Theories
– Natural language processing
Science Paradigms
Thousand years ago:
science was empirical
describing natural phenomena
Last few hundred years:
theoretical branch
using models, generalizations
Last few decades:
a computational branch
simulating complex phenomena
Today:
data science (eScience)
unify theory, experiment, and simulation
– Data captured by instruments
or generated by simulator
– Processed by software
– Information/Knowledge stored in computer
– Scientist analyzes database / files
using data management and statistics
2
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Information extraction, data mining
and natural language processing
• Natural language processing is the processing and
understanding of human language by machines
• Information Extraction can be considered a subclass
• Also known as knowledge extraction
• Data mining is the process of discovering new
patterns from large data sets
• Text mining is the data mining of text
• Text analytics generally refers to the tools used
• Information extraction is the process of extracting
and labeling relevant data from large data sets,
usually text
• Large means manually unreasonable
The Value of Unstructured Text Data
“Unstructured” text data is the primary form of human-generated
information
– Business and government reports, blogs, web pages, news,
scientific literature, online reviews, …
Need to extract information and give it structure to effectively
manage, search, mine, store and utilize this data
Information Extraction: maturing, and active research area
– Software and companies exist
– Intersection of Computational Linguistics, Machine
Learning, Data mining, Databases, and Information
Retrieval
Active crawling for text data
Example: Answering Queries Over
Text
For years, Microsoft
Corporation CEO Bill
Gates was against open
source. But today he
appears to have changed
his mind. "We can be
open source. We love the
concept of shared
source," said Bill Veghte,
a Microsoft VP. "That's a
super-important shift for
us in terms of code
access.“
Richard Stallman,
founder of the Free
Software Foundation,
countered saying…
Select Name
From PEOPLE
Where Organization = ‘Microsoft’
PEOPLE
Name
Bill Gates
Bill Veghte
Richard Stallman
Title
Organization
CEO
Microsoft
VP
Microsoft
Founder Free Soft..
Bill Gates
Bill Veghte
(from William Cohen’s IE tutorial, 2003)
Information extraction from text or pdfs
For years, Microsoft
Corporation CEO Bill
Gates was against open
source. But today he
appears to have changed
his mind. "We can be
open source. We love the
concept of shared
source," said Bill Veghte,
a Microsoft VP. "That's a
super-important shift for
us in terms of code
access.“
Richard Stallman,
founder of the Free
Software Foundation,
countered saying…
(William Cohen’s IE tutorial, 2003)
Select Name
From PEOPLE
Where Organization = ‘Microsoft’
PEOPLE
Name
Bill Gates
Bill Veghte
Richard Stallman
Title
Organization
CEO
Microsoft
VP
Microsoft
Founder Free Soft..
XML or database
For extraction of OAI metadata from academic documents, see
CiteSeerX
citeseerx.ist.psu.edu
Information Extraction Tasks
Extracting entities and relations: this talk
– Entities: named (e.g., Person) and generic (e.g., disease name)
– Relations: entities related in a predefined way (e.g., Location of a
Disease outbreak, or a CEO of a Company)
– Events: can be composed from multiple relation tuples
Common extraction subtasks:
– Preprocess: sentence chunking, syntactic parsing, morphological
analysis
– Create rules or extraction patterns: hand-coded, machine learning, and
hybrid
– Apply extraction patterns or rules to extract new information
– Postprocess and integrate information
• Co-reference resolution, deduplication, disambiguation
Entities
Wikipedia: An entity is something that has a distinct, separate
existence, although it need not be a material existence.
Features:
–
–
–
–
–
–
–
–
Permanent vs transient
Unique vs common
Animate vs inanimate
Small vs large
Mobile vs sessile
Place vs thing
Abstract vs real
Bio labels
Digital mention or reference
Example: Extracting Entities from
Text
– Useful for data warehousing, data cleaning, web data
integration
Address
Citation
House
number
Building
Road
City
State
Zip
4089 Whispering Pines Nobel Drive San Diego CA 92122 1
Ronald Fagin, Combining Fuzzy Information from Multiple
Systems, Proc. of ACM SIGMOD, 2002
Segment(si)
Sequence
Label(si)
S1
Ronald Fagin
Author
S2
Combining Fuzzy Information from Multiple Systems
Title
S3
Proc. of ACM SIGMOD
Conference
S4
2002
Year
Entity Disambiguation
Task of clustering and linking similar entities in a document
or between documents.
– Labels sometime complex are given to these entities
Sometimes includes task of extracting or finding those
entities (information extraction, focused crawling, etc)
Hand-Coded Methods
Easy to construct in some cases
– e.g., to recognize prices, phone numbers, zip codes,
conference names, etc.
Intuitive to debug and maintain
– Especially if written in a “high-level” language:
ContactPattern  RegularExpression(Email.body,”can be reached at”)
[IBM Avatar]
– Can incorporate domain knowledge
Scalability issues:
–
–
–
–
Labor-intensive to create
Highly domain-specific
Often corpus-specific
Rule-matches can be expensive
Entity Disambiguation by some other name?
record linkage
merge/purge processing or list washing
data matching
object identity problem
named entity resolution
duplicate detection
record matching
instance identification
deduplication
coreference resolution
reference reconciliation
database hardening
Closely related to Natural Language Processing
Entity Disambiguation Applications
Speech understanding
Question/answering
Health records
Criminal activities
Finance records
Semantic web applications
Scientific discovery and search
Semantic search
Others?
Entity Tagging
Identifying mentions of entities (e.g., person names, locations, companies) in
text
– MUC (1997): Person, Location, Organization, Date/Time/Currency
– ACE (2005): more than 100 more specific types
Hand-coded vs. Machine Learning approaches
Best approach depends on entity type and domain:
– Closed class (e.g., geographical locations, disease names, gene & protein
names): hand coded + dictionaries
– Syntactic (e.g., phone numbers, zip codes): regular expressions
– Semantic (e.g., person and company names): mixture of context, syntactic
features, dictionaries, heuristics, etc.
– “Almost solved” for common/typical entity types
Machine Learning Methods
Can work well when lots of training data and easy to construct
Can capture complex patterns that are hard to encode with handcrafted rules
– e.g., determine whether a review is positive or negative
– extract long complex gene names
– Non-local dependencies
The human T cell leukemia lymphotropic virus type 1 Tax protein
represses MyoD-dependent transcription by inhibiting MyoDbinding to the KIX domain of p300.“
[From AliBaba]
Representation Models [Cohen and McCallum, 2003]
Classify Pre-segmented
Candidates
Lexicons
Abraham Lincoln was born in Kentucky
member?
Alabama
Alaska
…
Wisconsin
Wyoming
Boundary Models
Abraham Lincoln was born in Kentucky.
.Abraham Lincoln was born in Kentucky.
Sliding Window
Abraham Lincoln was born in Kentucky.
Classifier
Classifier
which class?
which class?
Try alternate
window sizes:
Finite State Machines
Abraham Lincoln was born in Kentucky.
Context Free Grammars
Abraham Lincoln was born in Kentucky.
BEGIN
Most likely state sequence?
NNP
NNP
V
V
P
Classifier
PP
which class?
VP
NP
BEGIN
END
BEGIN
NP
END
VP
S
Any of these models can be used to capture words, formatting or both.
…and beyond
(Person) Name Disambiguation
Person Name disambiguation
– A person can be referred to in different ways with different attributes in multiple records, the goal of name
disambiguation is to resolve such ambiguities, linking and merging all the records of the same entity
together
– Large # of mentions and entities
Consider three types of person name ambiguities:
– Aliases - one person with multiple aliases, name variations, or name changed
e.g. CL Giles & Lee Giles, Superman & Clark Kent
–
Common Names - more than one person shares a common name,
e.g. Jian Huang – 118 papers in DBLP
–
Typography Errors - resulting from human input or automatic extraction
Goal: disambiguate, cluster and link names in a large digital library or
bibliographic resource such as Medline
Popular Machine Learning Methods
For details: [Feldman, 2006 and Cohen, 2004]
Naive Bayes
SRV [Freitag 1998], Inductive Logic Programming
Rapier [Califf and Mooney 1997]
Hidden Markov Models [Leek 1997]
Maximum Entropy Markov Models [McCallum et al. 2000]
Conditional Random Fields [Lafferty et al. 2001]
Scalability
– Can be labor intensive to construct training data
– At run time, complex features can be expensive to construct or process
(batch algorithms can help: [Chandel et al. 2006] )
Data mining?
Process of semi-automatically analyzing large data sets
and databases to find patterns that are:
–
–
–
–
valid: hold on new data with some certainity
novel: non-obvious to the system
useful: should be possible to act on the item
understandable: humans should be able to interpret the
pattern
Evolution of Data Mining
<http://www.thearling.com/text/dmwhite/dmwhite.htm>
Evolutionary Step
Business Question
Data Collection
(1960s)
"What was my total
revenue in the last five
years?"
Data Access
(1980s)
"What were unit sales in Relational databases
Retrospective, dynamic
New England last
(RDBMS), Structured
data delivery at record
March?"
Query Language (SQL), level
ODBC
Data Warehousing &
Decision Support
(1990s)
"What were unit sales in
New England last
March? Drill down to
Boston."
Data Mining
(Emerging Today)
Enabling
Technologies
Computers, tapes, disks
On-line analytic
processing (OLAP),
multidimensional
databases, data
warehouses
"What’s likely to
Advanced algorithms,
happen to Boston unit multiprocessor
sales next month?
computers, massive
Why?"
databases
Characteristics
Retrospective, static
data delivery
Retrospective, dynamic
data delivery at multiple
levels
Prospective, proactive
information delivery
Data Mining is Ready for Prime Time
• Data mining is ready for general application
because it engages three technologies that are
now sufficiently mature:
 Massive data collection & delivery
 Powerful multiprocessor computers
 Sophisticated data mining algorithms
Organizational Reasons to use Data
Mining
– Most organizations already collect and refine massive
quantities of data.
– Their most important information is in their data warehouses.
– Data mining moves beyond the analysis of past events … to
predicting future trends and behaviors that may be missed
because they lie outside the experts’ expectations.
– Data mining tools can answer complex business questions
that traditionally were too time-consuming to resolve.
– Data mining tools can explore the intricate interdependencies
within databases in order to discover hidden patterns and
relationships.
– Data mining allows decision-makers to make proactive,
knowledge-driven decisions.
A Key Concept for Data Mining
• Data Mining delivers actionable data :
– data that support decision-making
– data that lead to knowledge and understanding
– data with a purpose
• i.e., Data do not exist for their own sake.
• The Data Warehouse is a corporate asset
(whether in business, marketing, banking,
science, telecommunications, entertainment,
computer security, or security).
Data Mining - the up side
Data mining is everywhere:
–
–
–
–
–
–
–
–
–
Huge scientific databases (NASA, Human Genome,…)
Corporate databases (OLAP)
Credit card usage histories (Capital One)
Loan applications (Credit Scoring)
Customer purchase records (CRM)
Web traffic analysis (Doubleclick)
Network security intrusion detection (Silent Runner)
The hunt for terrorists
The NBA!
Data Mining - the down side
• Data mining is a pejorative in the business
database community (“data dredging”)
– They prefer to call it Knowledge Discovery, or
Business Intelligence, or CRM (Customer
Relationship Management), or Marketing, or
OLAP (On-Line Analytical Processing)
• Legal issues in many countries
• The Data Mining Moratorium Act of 2003
– debated within the U.S.Congress
– privacy concerns
– directly primarily against the DARPA TIA Program
(Total Information Awareness)
Characteristics of The Information Age:
• Data “Avalanche”
– the flood of Terabytes of data is already happening, whether
we like it or not
– our present techniques of handling these data do not scale
well with data volume
• Distributed Digital Archives
– will be the main access to data
– will need to handle hundreds to thousands of queries per day
• Systematic Data Exploration and Data Mining
– will have a central role
• statistical analysis of “typical” events
• automated search for “rare” events
The Data Flood is Everywhere
Huge quantities of data are
being generated in all
business, government, and
research domains:
– Banking, retail, marketing,
telecommunications, other
business transactions ...
– Scientific data: genomics,
astronomy, biology, etc.
– Web, text, and e-commerce
Data Growth Rate
Exabytes
10-fold
Growth in 5
Years!
DVD
RFID
Digital TV
MP3 players
Digital cameras
Camera phones, VoIP
Medical imaging, Laptops,
Data center applications, Games
Satellite images, GPS, ATMs, Scanners
Sensors, Digital radio, DLP theaters, Telematics
Peer-to-peer, Email, Instant messaging, Videoconferencing,
CAD/CAM, Toys, Industrial machines, Security systems, Appliances
Source: IDC, 2008
What is Data Mining?
Data mining is defined as “an information extraction
activity whose goal is to discover hidden facts
contained in (large) databases."
Data mining is used to find patterns and relationships in
data. (EDA = Exploratory Data Analysis)
Patterns can be analyzed via 2 types of models:
– Descriptive : Describe patterns and create
meaningful subgroups or clusters.
– Predictive : Forecast explicit values, based upon
patterns in known results.
How does this become useful (not just bits of data)? ...
– … through KNOWLEDGE DISCOVERY
Data  Information  Knowledge  Understanding / Wisdom!
Historical Note:
Many Names of Data Mining
Data Fishing, Data Dredging: 1960– used by Statisticians (as a bad name)
Data Mining :1990– used by DB & business communities
– in 2003 – bad image because of DARPA TIA
Knowledge Discovery in Databases (1989-)
– used by AI & Machine Learning communities
also Data Archaeology, Information Harvesting, Information
Discovery, Knowledge Extraction, ...
Currently: Data Mining and Knowledge Discovery
are seemed to be used interchangeably.
Relationship with other fields
Overlaps with machine learning, statistics, artificial
intelligence, databases, visualization but more stress
on
– scalability of number of features and instances
– stress on algorithms and architectures whereas foundations
of methods and formulations provided by statistics and
machine learning.
– automation for handling large, heterogeneous data
Some basic operations
Predictive:
– Regression
– Classification
– Collaborative Filtering
Descriptive:
– Clustering / similarity matching
– Association rules and variants
– Deviation detection
Data Mining Examples
• Classic Textbook Example of Data Mining (Legend?):
Data mining of grocery store logs indicated that men who buy
diapers also tend to buy beer at the same time.
• Blockbuster Entertainment mines its video rental history
database to recommend rentals to individual customers.
• A financial institution discovered that credit applicants who
used pencil on the form were much more likely to default on
their debts than those who filled out the application using ink.
• Credit card companies recommend products to cardholders
based on analysis of their monthly expenditures.
• Airline purchase transaction logs revealed that 9-11 hijackers
bought one-way airline tickets with the same credit card.
• Astronomers examined objects with extreme colors in a huge
database to discover the most distant Quasars ever seen.
Data Mining Application:
Marketing
 Sales Analysis
• associations between product sales:
• beer and diapers
• strawberry pop tarts and beer (and hurricanes)
 Customer Profiling
• data mining can tell you what types of customers
buy what products
 Identifying Customer Requirements
• identify the best products for different customers
• use prediction to find what factors will attract new
customers
Data Mining Application:
Fraud Detection
 Auto Insurance Fraud
• Association Rule Mining can detect a group of people
who stage accidents to collect on insurance
 Money Laundering
• Since 1993, the US Treasury's Financial Crimes
Enforcement Network agency has used a data-mining
application to detect suspicious money transactions
 Banking: Loan Fraud
• Security Pacific/Bank of America uses data mining to
help with commercial lending decisions and to prevent
fraud
The Necessity of Data Mining
• Enormous interest in these data collections.
• The environment to exploit these data does not
exist!
– 1 Terabyte at 100 Mbits/sec takes 1 day to transfer.
– Hundreds to thousands of queries per day.
– Data will reside at multiple locations, in many different
formats.
– Existing analysis tools do not scale to Terabyte data
collections.
• The need is acute! A solution will not just happen.
What is Knowledge Discovery?
• Knowledge discovery refers to “finding out new
knowledge about an application domain using data
on the domain usually stored in a database.”
– Application domains: scientific, customer purchase records,
computer network logs, web traffic logs, financial transactions,
census data, basketball play-by-play histories, ...
• Why are Data Mining & Knowledge Discovery such hot
topics? --- because of the enormous interest in these
huge databases and their potential for new discoveries.
• In large databases, Data Mining and Knowledge
Discovery come in two flavors:
– Event-based mining
– Relationship-based mining
Event-Based Mining
(Event-based mining is based upon events or trends in data.)
Four distinct orthogonal categorizations:
• Known events / known models - use existing models (descriptive
models) to locate known phenomena of interest either spatially or
temporally within a large database.
• Known events / unknown models - use clustering properties of
data to discover new relationships and patterns among known
phenomena.
• Unknown events / known models - use known associations and
relationships (predictive models) among parameters that describe a
phenomenon to predict the presence of previously unseen examples
of the same phenomenon within a large complex database.
• Unknown events / unknown models - use thresholds or trends to
identify transient or otherwise unique ("one-of-a-kind") events and
therefore to discover new phenomena.  Serendipity!
Relationship-Based Data Mining
(Based upon associations & relationships among data items)
• Spatial associations -- identify events or objects at the
same physical spatial location, or at related locations
(e.g., urban versus rural data).
• Temporal associations -- identify events or transactions
occurring during the same or related periods of time
(e.g., periodically, or N days after event X).
• Coincidence associations -- use clustering techniques
to identify events that are co-located (that coincide) within
a multi-dimensional parameter space.
User Requirements for a Data Mining System
(What features must a DM system have for users?)
• Cross-Identification - refers to the classical problem of
associating the objects listed in one database to the objects listed
in another.
• Cross-Correlation - refers to the search for correlations,
tendencies, and trends between parameters in multi-dimensional
data, usually across databases.
• Nearest-Neighbor Identification - refers to the general
application of clustering algorithms in multi-dimensional
parameter space, usually within a single database.
• Systematic Data Exploration - refers to the application of the
broad range of event-based and relationship-based queries to
one or more databases in the hope of making a serendipitous
discovery of new events/objects or a new class of events/objects.
Representative Data Mining
Architecture
<http://www.thearling.com/text/dmwhite/dmwhite.htm>
Data leads to Knowledge leads to
Understanding
Data  Information  Knowledge  Understanding / Wisdom!
EXAMPLE :
Data = 00100100111010100111100 (stored in database)
Information = ages and heights of children (metadata)
Knowledge = the older children tend to be taller
Understanding = children’s bones grow as they get older
Astronomy Example
Data:
(a) Imaging data (ones & zeroes)
Information (catalogs / databases):
(b) Spectral data
(ones & zeroes)
– Measure brightness of galaxies from image (e.g., 14.2 or 21.7)
– Measure redshift of galaxies from spectrum (e.g., 0.0167 or 0.346)
Knowledge:
Hubble Diagram 
Redshift-Brightness
Correlation 
Redshift = Distance
Understanding: the Universe is expanding!!
Goal of Data Mining
The end goal of data mining is not the data themselves, but the
new knowledge and understanding that are revealed in the
process = Business Intelligence (BI).
(Remember what we said about the business community’s opinion of
D.M.)
This is why the research field is usually referred to as KDD =
Knowledge Discovery in Databases.
The Data Mining Process
The most important and time-consuming
step is Cleaning the Data.
Data Mining Methods and Some Examples
Clustering
Classification
Associations
Neural Nets
Decision Trees
Pattern Recognition
Correlation/Trend Analysis
Principal Component Analysis
Regression Analysis
Outlier/Glitch Identification
Visualization
Autonomous Agents
Self-Organizing Maps (SOM)
Link (Affinity) Analysis
Find all groups and classes of
objects represented in the data
Classify new data items using
the known classes & groups
Find associations and patterns
among different data items
Organize information in the
database based on relationships
among key data descriptors
Identify linkages between data items
based on features shared in common
Some Data Mining Techniques
Graphically Represented
Self-Organizing Map (SOM)
Link Analysis
Clustering
Decision Tree
Neural Network
Outlier (Anomaly) Dectection
Data Mining Technique: Clustering
In this case,
three different
groups (classes)
of items were
found among
all of the items
in the data set.
Data Mining Technique:
Decision Tree Classification
Question:
Should I play
tennis today?
Similar to game
“20 questions”
Same technique used
by bank loan officers to
identify good potential
customers versus poor
customers.
(I must really love tennis!)
Data Mining Technique:
Association Rule Mining
(Market Basket Analysis)
sales
records:
tran1
tran2
tran3
tran4
tran5
tran6
cust33
cust45
cust12
cust40
cust12
cust12
p2,
p5,
p1,
p5,
p2,
p9
p5, p8
p8, p11
p9
p8, p11
p9
• Trend (Rule): Products p5, p8 often bought together
• Trend (Rule): Customer 12 likes product p9
Data Mining Algorithm: The SOM
Figure: The SOM (SelfOrganizing Map) is one
technique for organizing
information in a database
based upon links between
concepts.
It can be used to find
hidden relationships and
patterns in more complex
data collections, usually
based on links between
keywords or metadata.
Data Mining Application:
Outlier Detection
Figure: The clustering of data
clouds (dc#) within a
multidimensional parameter
space (p#).
Such a mapping can be used to
search for and identify clusters,
voids, outliers, one-of-kinds,
relationships, and associations
among arbitrary parameters in a
database (or among various
parameters in geographically
distributed databases).
Link Analysis for Terrorist SNA
Find all connections and relationships among known terrorists.
Data Mining Technology:
Parallel Mining
Figure: Parallel Data Mining
The application of parallel
computing resources and
parallel data access (e.g.,
RAID) enables concurrent
drill-downs into large data
collections
Data Mining Methods Explained
•
Clustering: Group data items according to tight relationships.
•
Classification: Assign data items to predetermined groups.
•
Associations: Associate data with similar relationships. The beer-diaper example is an
example of associative mining.
•
Artificial Neural Networks (ANN): Non-linear predictive models that learn through training and
resemble biological neural networks in structure.
•
Decision Trees: Hierarchical sets of decisions, based upon rules, for rapid classification of a
data collection.
•
Sequential Patterns: Identify or predict behavior patterns or trends.
•
Genetic Algorithms: Rapid optimization techniques that are based on the concepts of natural
evolution.
•
Nearest Neighbor Method: Classify a data item according to its nearest neighbors (records
that are most similar).
•
Rule induction: The extraction of useful if-then rules from data based on statistical
significance.
•
Data visualization: The illustration and visual interpretation of complex relationships in
multidimensional data using graphics tools.
•
Self-Organizing Map (SOM): Graphically organizes (in a 2-dimensional map) the information
stored within a database based upon similarities and links between concepts. It can be used
to find hidden relationships and patterns in more complex data collections.
Data Mining Techniques: techniques are based on
Algorithms; techniques are used in Applications
KDnuggets
Tools used
Industries data
mining is used
http://www.kdnuggets.com/polls/2004/data_mining_applications_industries.
htm
Poll of Users: Where do you currently apply data mining? (August 2004)
“Industries/fields where you currently apply data mining?”
[216 votes total]
Banking (29) ………………………... 13%
Scientific data (20) …………………... 9%
Direct Marketing/Fundraising (19) …. 9%
Fraud Detection (19) ………………… 9%
Bioinformatics/Biotech (18) …………. 8%
Insurance (15) ………………………... 7%
Medical/Pharma (15) ………………… 7%
Telecommunications (12) …………… 6%
eCommerce/Web (12) ………………. 6%
Investment/Stocks (9) ……………….. 4%
Manufacturing (9) ……………………. 4%
Retail (9) ……………………………… 4%
Security (8) …………………………… 4%
Travel (2) ……………………………... 1%
Entertainment/News (1) ………………0.5%
Other (19) ……………………………... 9%
The importance of metadata and their rules
• So we have all this mined or extracted data: what is it?
• Label some of it and call it metadata
• You know what it is
• Make it available to others (if you can)
Tim Berners-Lee
– inventor of the world wide web
– Founder of the W3C
Presentation at Ted
Metadata (and Markup languages)
“Metadata is data about data”
Metadata often is written in XML
Metadata is semi-structured data conforming to commonly
agreed upon models, providing operational interoperability
in a heterogeneous environment
What is metadata?
Some simple definitions
‘Structured data about data’.
• Dublin Core Metadata Initiative FAQ, 2005
– http://dublincore.org/resources/faq/
Machine-understandable information about Web resources or
other things.
• Tim Berners-Lee, W3C, 1997
– http://www.w3.org/DesignIssues/Metadata
"Web resources or other things"
• Metadata might be "about"… anything!
–
–
–
–
–
–
–
HTML documents
digital images
databases
books
museum objects
archival records
metadata records
–
–
–
–
–
–
–
–
–
–
Web sites
collections
services
physical places
people
organizations
“works”
formats
concepts
events
What is metadata?
Towards a "functional" view
Data associated with objects which relieves their potential users of having to
have full advance knowledge of their existence or characteristics.
• Lorcan Dempsey & Rachel Heery, "Metadata: a current view of practice and
issues", 1998
–
http://www.ukoln.ac.uk/metadata/publications/jdmetadata/
Structured data about resources that can be used to help support a wide
range of operations.
• Michael Day, "Metadata in a Nutshell", 2001
–
http://www.ukoln.ac.uk/metadata/publications/nutshell/
What might metadata "say"?
What is this called?
What is this about?
Who made this?
When was this made?
Where do I get (a copy of) this?
When does this expire?
What format does this use?
Who is this intended for?
What does this cost?
Can I copy this? Can I modify this?
What are the component parts of this?
What else refers to this?
What did "users" think of this?
(etc!)
What operations/functions?
resource disclosure & discovery
resource retrieval, use
resource management, including preservation
verification of authenticity
intellectual property rights management
commerce
content-rating
authentication and authorization
personalization and localization of services
(etc!)
What operations/functions?
Different functions : different metadata
Metadata (and metadata standards) sometimes
classified according to function
– Descriptive: primarily for discovery, retrieval
– Administrative: primarily for management
– Structural: relationships between component parts of
resources
– Contextual: relationships between resources
No “one size fits all solution”!
Metadata importance
“data about data” is about as good as the definition
gets...
As a data resource grows, metadata becomes more
important
Lack of metadata has different consequences
– documentation: metadata can be regenerated automatically,
or by hand
– datasets, pictures: once lost, can be impossible to
regenerate
Types of Metadata
See http://www.loc.gov/standards/metadata.html
Descriptive
– Discovery / description of objects
• Title, author, abstract, etc.
Structural
– Storage & presentation of objects
• 1 pdf file, 1 ppt file, 1 LaTeX file, etc.
Administrative
– Managing and preservation of objects
• Access control lists, terms and conditions, format descriptions,
“meta-metadata”
Which View is Correct?
figure 1 from: http://www.dlib.org/dlib/january01/lagoze/01lagoze.html
Approaches to Metadata
from Ng, Park and Burnett, 1997 (also JASIS, 50(13))
http://www.scils.rutgers.edu/~sypark/asis.html
– library science: bibliographic control
• “organizing the physical containers of information, by means
of bibliographical description, subject analysis, and
classification notation construction, so that the container can be
efficiently described, identified, located and retrieved”
– computer and information science: data management
• “not only to store, access and utilize data effectively, but also
to provide data security, data sharing, and data integrity”
DL Metadata Issues
Who provides metadata?
– author? “publisher”? professional cataloger? extracted from
content?
Is metadata “integrated” with data?
– related question: is metadata a first class object?
Formats!
– which ones?
– extensible?
– paradox: the more powerful the format, the less likely it will be
used...
Metadata Formats and
Implementation
Use markup languages
– Interoperable
– Extensible
– Robust
Permits advance search features
When online, the beginning of a semantic
web!
What we covered
• Methods and tools for making sense of data
• Assists reasoning, decision making
• Data manipulation methods
• Large data
• How metadata helps
Importance of Data
“Data is not only important to science but also to the
humanities.”
“The sexy job in the next ten years will be ... to take data -to be able to understand it, to process it, to extract value
from it, to visualize it, to communicate it.” -- Hal Varian
(Economist, Berkeley & Google)
“Elite American university students do not think big
enough. That is exactly the complaint from some of the
largest technology companies and the federal government.
At the heart of this criticism is data.” -- New York Times
“Statistical agencies face increased demand for data
products, and the questions asked by our society are
becoming increasingly complex and hard to measure.
Meeting these challenges requires innovation [in] cognitive
research, and economic and statistical modeling.” -Roderick Little (Statistician, US Census and U Michigan)
Never too much Data
“Companies that manage their data well are 5% to 6% more
productive.” NYTimes
Building DBPedia
Words of wisdom
• "We have confused information (of which there is too
much) with ideas (of which there are too few)."
– Paul Theroux
• "The great Information Age is really an explosion of
non-information; it is an explosion of data ... it is
imperative to distinguish between the two; information
is that which leads to understanding."
– R.S. Wurman in his book: Information Anxiety2
Questions
• Role in information science of
• Information (knowledge) extraction
• Data mining
• Metadata
• What next?