Simple HTML Ontology Extensions

1
Simple HTML Ontology Extensions

• Ahmet Selman BozkirHacettepe University Computer
  Eng. Dept.

2
Contents

• Whats SHOE?
• What SHOE Isn't...
• Specifications
• Base Ontology of SHOE
• Creating a Basic Ontology
• Annotating an HTML document with SHOE
• Inferences in SHOE Ontologies
• References

3
Whats SHOE?

• HTML was never meant for computer consumption
  its function is for displaying data for humans to
  read. The "knowledge" on a web page is in a
  human-readable language (usually English), laid
  out with tables and graphics and frames in ways
  that we as humans comprehend visually.
• Unfortunately, intelligent agents aren't human.
  Even with state-of-the-art natural language
  technology, getting a computer to read and
  understand web documents is very difficult. This
  makes it very difficult to create an intelligent
  agent that can wander the web on its own, reading
  and comprehending web pages as it goes.
• So what can be done?

4
Whats SHOE?

• Answer is simply SHOE.
• SHOE eliminates this problem by making it
  possible for web pages to include knowledge that
  intelligent agents can actually read.
• SHOE is a small extension to HTML which allows
  web page authors to annotate their web documents
  with machine-readable knowledge. SHOE makes real
  intelligent agent software on the web possible.

5
Whats SHOE?

• SHOE is an HTML-based knowledge representation
  language.
• SHOE can be used to embed data from a variety of
  sources and for a variety of purposes. It is not
  intended for any one particular function.
  However, SHOE is primarily meant to make it
  possible for web robots and intelligent agents to
  finally make a dent in making all our lives a
  little easier.

6
Whats SHOE?

• Developed by Parallel Understanding Systems
  Group,
• Prof. Jim Hendler
• Department of Computer Science
• University of Maryland at College Park
• To sum up...
• Superset of HTML
• To specify ontologies for Internet-agents
• Annotate web documents semantically with machine
  readable knowledge
• Compatible to SGML and XML
• But now work at the University of Maryland on web
  ontologies continues in the Semantic Web and
  Agents Project , which uses the Web Ontology
  Languages OWL and DAMLOIL. These languages are
  results of standardization efforts that are in
  part based on SHOE

7
What SHOE Isn't...

• It is not just a meta-content language.It
  enables web designers to embed documents not only
  with information about the overall "content" of
  those documents but any arbitrary information at
  all. SHOE also allows agents to make automatic
  inferences about the data they learn, provides a
  hierarchical categorization scheme, and a
  sophisticated ontology mechanism designed
  specifically for the web needs
• It is purposely not a verbose knowledge-representa
  tion system.SHOE attempts to provide as rich
  expressivity as possible while keeping in mind
  that there's a tremendous amount of data out
  there.
• It does not have any pre-defined ontologies,
  categories, relationships, or inferences.SHOE is
  a language in which categories, relationships,
  attributes, inferences, etc. can be defined by
  ontologies, but SHOE itself does not define them.

8
Specifications

• Everything is started with adding this startup
  tag into head of your classic HTML document.
• ltMETA HTTP-EQUIV"SHOE" CONTENT"VERSION1.0"gt
• You may use this logo that represents your web
  page supports SHOE.

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Specifications

• SHOE uses the following additional tags as an
  extension to HTMLFor the definition of
  ontologiesONTOLOGY, /ONTOLOGY, USE-ONTOLOGY,
  DEF-CATEGORY,DEF-RELATION, /DEF-RELATION,
  DEF-ARG, DEF-RENAME,DEF-CONSTANT, DEF-TYPE,
  DEF-INFERENCE, /DEF-INFERENCE,INF-IF, /INF-IF,
  INF-THEN, /INF-THEN, COMPARISON,/COMPARISON,
  CATEGORY, RELATION, /RELATION, ARG.
• For the annotation of HTML-pages
  additionallyINSTANCE, /INSTANCE.

10
Creating a Basic Ontology

• ltHTMLgt ltHEADgtlt!--Indication that this document
  is conformant with SHOE 1.0-gt ltMETA
  HTTP-EQUIV"SHOE" CONTENT"VERSION1.0gt ltTITLEgt
  Our CS Ontology lt/TITLEgt lt/HEADgt ltBODYgtlt!--Dec
  laration of the ontologys name and
  version--gt ltONTOLOGY ID"cs-dept-ontology"
  VERSION"1.0gtlt!--Declaration to use another
  yet existing ontology--gt ltUSE-ONTOLOGY
  ID"base-ontology" VERSION"1.0" PREFIX"base
  URL"http//www.cs.umd.edu/projects/plus/SHOE/base
  .html"gt
• The prefix base is used to indicate explicit
  references to elementsof the imported base
  ontology.

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Creating a Basic Ontology

• Since our ontology deals with computer science
  departments, let's toss the following
  categorization facts into the ontology
• departments and research groups are
  organizations.
• faculty, assistants, and administrative staff are
  workers.
• workers and students are people.
• postdocs, lecturers, and professors are a
  faculty.
• research assistants and teaching assistants are
  assistants.
• graduate students and undergraduate students are
  students.
• secretaries are administrative staff.
• chairs are both professors and administrative
  staff.
• organizations, publications, and people are
  "basic items". The fact that chairs can be both
  professors and administrative staff indicates
  that SHOE provides multiple inheritance
  categories can have more than one supercategory.
  We declare all these things by saying

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Creating a Basic Ontology

• lt!-- Here we lay out our category hierarchy --gt
  ltDEF-CATEGORY NAME"Organization"
  ISA"base.SHOEEntity"gt ltDEF-CATEGORY
  NAME"Person" ISA"base.SHOEEntity"gt
  ltDEF-CATEGORY NAME"Publication"
  ISA"base.SHOEEntity"gt ltDEF-CATEGORY
  NAME"ResearchGroup" ISA"Organization"gt
  ltDEF-CATEGORY NAME"Department"
  ISA"Organization"gt ltDEF-CATEGORY NAME"Worker"
  ISA"Person"gt ltDEF-CATEGORY NAME"Faculty"
  ISA"Worker"gt ltDEF-CATEGORY NAME"Assistant"
  ISA"Worker"gt ltDEF-CATEGORY NAME"AdministrativeS
  taff" ISA"Worker"gt ltDEF-CATEGORY NAME"Student"
  ISA"Person"gt ltDEF-CATEGORY NAME"PostDoc"
  ISA"Faculty"gtltDEF-CATEGORY NAME"Lecturer"
  ISA"Faculty"gt ltDEF-CATEGORY NAME"Professor"
  ISA"Faculty"gt ltDEF-CATEGORY NAME"ResearchAssist
  ant" ISA"Assistant"gt ltDEF-CATEGORY
  NAME"TeachingAssistant" ISA"Assistant"gtltDEF-CAT
  EGORY NAME"GraduateStudent" ISA"Student"gt
  ltDEF-CATEGORY NAME"UndergraduateStudent"
  ISA"Student"gtltDEF-CATEGORY NAME"Secretary"
  ISA"AdministrativeStaff"gt ltDEF-CATEGORY
  NAME"Chair" ISA"AdministrativeStaff Professor"gt
  Note that Organization, Publication, and Person
  subcategorize from base.SHOEEntity, that is, the
  category SHOEEntity declared in base-ontology.
  SHOEEntity is the accepted "root" category for
  all categories you'll declare in an ontology,
  elements at the top of your category hierarchy
  should subcategorize from it.

Multiple Inheritance
13
SHOE Base Ontology

• This ontology is declared in this document both
  in human-readable form (what you see in front of
  you now) and machine-readable SHOE form (which
  you can see from viewing the html source of this
  document) . This base ontology is compatible with
  version 1.0 of SHOE. 1. Declared Types
• This ontology declares four basic types, listed
  below along with their description.
• STRING HTML String Literals, as defined in the
  HTML 2.0 specification.
• NUMBER Floating-point numerical constants.
  Knowledge-agents should be able to read common
  floating-point numbers like 2, 2.0, -1.432e4,
  etc.
• DATE Date/Timestamps following RFC 1123, as
  shown in section 3.3.1 of the HTTP/1.0
  specification.
• TRUTH HTML String Literals of the form YES or
  NO, case-insensitive.

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SHOE Base Ontology

• 2. ISA Hierarchy (Taxonomy)
• The following taxonomy is the collection of
  categories declared in this ontology. The
  hierarchical form is intended to show the ISA
  chain.
• Entity SHOEEntity
• Entity The top level of all SHOE
  classifications. You should not subclass from
  Entity--usually you should subclass from
  SHOEEntity or one of its subclasses instead.
  Entity exists to give the base ontology some
  flexibility for later versions.SHOEEntity This
  should be the root (ancestor) category for all
  categories declared in SHOE ontologies (other
  than the Base Ontology). All categories are best
  hung off of SHOEEntity or a subcategory.

Entity
SHOEEntity
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Part of cs-dept-ontology

• base.Entity base.SHOEEntity
  Person Worker
  Faculty
  Professor
  AssistantProfessor
  
  AssociateProfessor
  FullProfessor
  VisitingProfessor
  Lecturer
  PostDoc
  Assistant
  ResearchAssistant
  TeachingAssistant
  AdministrativeStaff
  Director
  Chair Professor
  Dean Professor
  ClericalStaff
  SystemsStaff Student
  UndergraduateStudent
  GraduateStudent
  Organization
  Department
  School

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SHOE Base Ontology

• 3. Relationships
• Relationships are declared between one or more
  arguments. Relationship arguments are either
  types or are categories. If the argument is a
  category, any subcategory of that category is
  valid as well.
• Relation Argument 1
  Argument 2
  description Entity STRING name
  Entity STRING description This is
  a human-readable description of a particular
  instance. name This is a human-readable name
  for a particular instance. Note that STRING is
  used without a period (as in ".STRING") because
  this is the base ontology, where it is declared.
  In other ontologies you make, you should use the
  period or a full prefix chain to refer to it and
  other types, relations, and categories declared
  in the base ontology.

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Creating a Basic Ontology (contd)

• Now, let's add to our ontology some simple
  relationships between elements of different
  categories.
• students have professors as advisors.
• organizations have members.
• people author publications

18
Creating a Basic Ontology

• ltDEF-RELATION NAME"advisor"gt ltDEF-ARG POS"1"
  TYPE"Student"gt ltDEF-ARG POS"2"
  TYPE"Professor"gt lt/DEF-RELATIONgt ltDEF-RELATION
  NAME"member"gt ltDEF-ARG POS"1"
  TYPE"Organization"gt ltDEF-ARG POS"2"
  TYPE"Person"gtlt/DEF-RELATIONgtltDEF-RELATION
  NAME"publicationAuthor"gt ltDEF-ARG POS"1"
  TYPE"Publication"gt ltDEF-ARG POS"2"
  TYPE"Person"gt lt/DEF-RELATIONgtPOS is used
  define the position of the arguments 1...n

19
Creating a Basic Ontology

• It's also often useful to use relationships
  other than just classifications. We can also have
  the following kinds of relationships with
  specific kinds of data types
• publications are published on a date.
• students' age is a number.
• everything can have a name which is a string
  (that is, a phrase like "Robert Kohout").
• whether a professor is tenured or not is a truth
  (a value of "YES" or "NO")

20
Creating a Basic Ontology

• ltDEF-RELATION NAME"publicationDate"gt ltDEF-ARG
  POS"1" TYPE"Publication"gt ltDEF-ARG POS"2"
  TYPE".DATE"gtlt/DEF-RELATIONgtltDEF-RELATION
  NAME"age"gt ltDEF-ARG POS"1" TYPE"Person"gt ltDEF
  -ARG POS"2" TYPE".NUMBER"gtlt/DEF-RELATIONgtltDEF-
  RELATION NAME"name"gt ltDEF-ARG POS"1"
  TYPE"base.SHOEEntity"gt ltDEF-ARG POS"2"
  TYPE".STRING"gtlt/DEF-RELATIONgtltDEF-RELATION
  NAME"tenured"gt ltDEF-ARG POS"1"
  TYPE"Professor"gt ltDEF-ARG POS"2"
  TYPE".TRUTH"gtlt/DEF-RELATIONgtlt/ONTOLOGYgt lt/BODYgt
  lt/HTMLgtThe dot . is used as an abbreviation
  for accessingelements of the SHOE base ontology.

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Annotating a HTML document

• ltHTMLgtltHEADgt ltTITLEgtMy Pagelt/TITLEgt lt/HEADgt
  ltBODYgt ltPgt Hi, this is my web page. I am a
  graduate student and a research assistant. lt/Pgt
  ltPgt Also, I'm 52 years old. lt/Pgt ltPgt My name
  is George Stephanopolous. lt/Pgt ltPgt Here is a
  pointer to my ltA HREF"http//www.cs.umd.edu/smith
  "gt graduate advisor.lt/Agtlt/Pgt ltPgt And ltA
  HREF"http//www.cs.umd.edu/papers/paper.ps"gt is
  a paper I recently wrote. lth3gt Brun Hilda lt/h3gt
  Brun Hilda is a visiting lecturer here from
  Germany who doesn't have her own web page.
  However, because I am such a nice person, I have
  agreed to let part of my web page space belong to
  her. She is 23. lt/BODYgtlt/HTMLgt

22
Annotating an HTML document

• This page tells us
• That the web page is about a
• graduate student
• research assistant
• The person's name is George Stephanopolous.
• The person is 52 years old.
• The person's graduate advisor is
  http//www.cs.umd.edu/smith
• The person is the author of the paper
  http//www.cs.umd.edu/papers/paper.ps
• Further, we've learned some interesting facts
  about Brun Hilda
• She's a lecturer.
• She is 23 years old.
• Her name is Brun Hilda.

23
Annotating an HTML document

• It so happens that we want to tell these exact
  things to intelligent agents and other
  knowledge-gatherers. To do this, we first need to
  tell the robot that we're using SHOE and uniquely
  define our document as an instance.
• An instance is similar to an "entity" as defined
  in the database world. However, we don't use the
  term "entity" because "entity" already in common
  use in another way in HTML and SGML. We begin by
  declaring that our page uses SHOE 1.0-compliant
  tags. To do this, in the HEAD section of our
  document, we add
• ltMETA HTTP-EQUIV"SHOE" CONTENT"VERSION1.0"gt

24
Annotating an HTML document

• Instances and KeysBefore we can add semantic
  information to our web page, we need to define
  one or more instances, which are data objects
  which we will classify or relate to one another.
  It's paramount that instance be unique from one
  another--we wouldn't want two people writing
  instances with the same name. SHOE handles this
  by associating with each instance a unique key.
  SHOE has a standard protocol for coming up with
  a key for instances base them on one (and only
  one) URL for the web page they're found on. For
  example, an instance about my dog Fido, found on
  some web page http//www.example.com/example.html,
  might have the key "http//www.example.com/exampl
  e.htmlfido". Or Richard Nixon's home page
  might contain a single instance with just his URL
  as key "http//www.whitehouse.gov/trickydick.html
  ". A web page might have many URLs that lead to
  it, so you'll have to pick which one you'll use
  as its official key and stick with that. This
  effectively guarantees that instance on other
  documents can't have the same keys as ones on
  your document, since no two documents can share
  the same URL (unless one went away and the other
  replaced it).ltINSTANCE KEY"http//www.cs.umd.ed
  u/users/george/"gt

25
Annotating an HTML document

• Then declare which ontology will be used..
• ltUSE-ONTOLOGY ID"cs-dept-ontology"
  URL"http//www.cs.umd.edu/projects/plus/SHOE/onts
  /cs.html" VERSION"1.0" PREFIX"cs"gt

26
Annotating an HTML document

• CategorizationNext, we'll classify or
  categorize the instance we're declaring on this
  web page--that is, we'll declare what the
  instance concerns. In SHOE, categorization is
  done using the CATEGORY tag in conjunction with
  one or more categories we've picked from the
  ontology we're using. In the body of the
  document, we'll add
• ltCATEGORY NAME"cs.GraduateStudent"gtltCATEGORY
  NAME"cs.ResearchAssistant"gt This says that
  this instance belongs to the classes or
  categories "GraduateStudent" and
  "ResearchAssistant" as defined in the ontology
  we've defined to use the "cs." prefix (i.e.,
  cs-dept-ontology).

27
Annotating an HTML document

• Declaring RelationshipsNext we'd like to tell
  web robots about relationships to other instances
  and data. We'll start with the relationships
  between the instance we're creating and some
  ordinary data like our name and age.
• ltRELATION NAME"cs.name"gt ltARG POS1
  VALUE"http//www.cs.umd.edu/users/george/"gt ltARG
  POS2 VALUE"George Stephanopolous"gt lt/RELATIONgt
  ltRELATION NAME"cs.age"gt ltARG POS1
  VALUE"http//www.cs.umd.edu/users/george/"gt ltARG
  POS2 VALUE"52"gt lt/RELATIONgt

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Annotating an HTML document

• A Nested InstanceFinally, poor Brun Hilda, who
  only exists World-Wide-Web-wise as a mention on
  our web page, should get an instance all her own
  so we can declare facts about her. Brun Hilda
  will be sharing space on George's web page, so
  her instance needs a URL different from his
  instance, but also based on his URL.

29
Annotating an HTML document

• ltINSTANCE KEY"http//www.cs.umd.edu/users/geor
  ge/BRUNHILDA"gt ltCATEGORY NAME"cs.Lecturer"gtlt
  RELATION NAME "cs.namegt ltARG POSTO
  VALUE"Brun Hildagtlt/RELATIONgtltRELATION
  NAME"cs.age"gt ltARG POSTO VALUE"23gtlt/RELATION
  gtlt/INSTANCEgt

30
Annotating an HTML document

• Final ProductltINSTANCE KEY"http//www.cs.umd.ed
  u/users/george/"gt ltUSE-ONTOLOGY
  ID"cs-dept-ontology" URL"http//www.cs.umd.edu/p
  rojects/plus/SHOE/onts/cs.html" VERSION"1.0"
  PREFIX"cs"gt ltCATEGORY NAME"cs.GraduateStudent"
  gt ltCATEGORY NAME"cs.ResearchAssistant"gt
  ltRELATION NAME"cs.name"gt ltARG POSTO
  VALUE"George Stephanopolous"gt lt/RELATIONgtltRELAT
  ION NAME"cs.age"gt ltARG POSTO
  VALUE"52"gtlt/RELATIONgtltRELATION
  NAME"cs.advisor"gt ltARG POSTO
  VALUE"http//www.cs.umd.edu/users/smith"gt
  lt/RELATIONgt

31
Annotating an HTML document

• ltINSTANCE KEY"http//www.cs.umd.edu/users/ge
  orge/BRUNHILDA"gt ltCATEGORY NAME"cs.Lecturergt
  ltRELATION NAME "cs.name"gt ltARG POSTO
  VALUE"Brun Hilda"gt lt/RELATIONgt ltRELATION
  NAME"cs.agegt ltARG POSTO VALUE"23gt lt/RELATI
  ONgt lt/INSTANCEgtlt/INSTANCEgtlt/BODYgt lt/HTMLgt

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Inferences in SHOE Ontologies

• Ontologies don't just declare hierarchical
  categories and valid relationships. They may also
  declare things that may be inferred from existant
  claims.
• Let's say we wanted to add to our
  cs-dept-ontology the inference that if someone
  claims to be a member of an organization, and
  that organization is a suborganization of a
  second organization, then the person is also a
  member of that second organization.
• This would save people from claiming that they're
  both a member of a research group and its
  department, for example.Horn-Clauses are used
  to specify inference-rules in SHOE.

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Inferences in SHOE Ontologies

• To do this, we should first lay this inference
  out in a logical format called a Horn Clause. A
  Horn clause consists of a head and a body,
  separated with a "-". In the head and body are
  claims the body can have more than one claim,
  joined with a "", which means "and". Claims in a
  Horn clause usually contain variables, which are
  wildcards that can be matched against anything,
  so long as variables of the same name are matched
  to the same thing. Here's our inference in a Horn
  Clause (we'll put question marks in front of
  variables)
• member(?org2,?person) - member(?org1,?person)
  subOrganizationOf(?org1,?org2)
• This is read as "?person is a member of ?org2 if
  ?person is a member of ?org1 and ?org1 is a
  suborganization of ?org2". In the
  cs-dept-ontology, this would be written as
  follows

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Inferences in SHOE Ontologies

• ltDEF-INFERENCE DESCRIPTION"member(?org2,?person)
  if member(?org1,?person) and subOrganizationOf(?o
  rg1,?org2)"gt ltINF-IFgt ltRELATION
  NAME"member"gt ltARG POS1 VALUE"org1"
  USAGEVARgt ltARG POS2 VALUE"per" USAGEVARgt
  lt/RELATIONgt ltRELATION NAME"subOrganizationOf"
  gt ltARG POS1 VALUE"org1" USAGEVARgt ltARG
  POS2 VALUE"org2" USAGEVARgt lt/RELATIONgt
  lt/INF-IFgt ltINF-THENgt ltRELATION
  NAME"member"gt ltARG POS1 VALUE"org2"
  USAGEVARgt ltARG POS2 VALUE"per"
  USAGEVARgt lt/RELATIONgtlt/INF-THENgtlt/DEF-INFERENC
  Egt

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References

• http//www.cs.umd.edu/projects/plus/SHOE

36

• Thanks for Listening meHacettepe University