Semantic Web for the Working Ontologist - Effective Modeling in RDFS and OWL

Front Cover

Semantic Web for the Working Ontologist Modeling in RDF, RDFS and OWL

Copyright Page

Contents

Preface

About the Authors

Chapter 1: What Is the Semantic Web?

What Is a Web?

Smart Web, Dumb Web

Smart Web Applications

A Connected Web Is a Smarter Web

Semantic Data

A Distributed Web of Data

Features of a Semantic Web

What about the Round-Worlders?

To Each Their Own

There's Always One More

Summary

Fundamental Concepts

Chapter 2: Semantic Modeling

Modeling for Human Communication

Explanation and Prediction

Mediating Variability

Variation and Classes

Variation and Layers

Expressivity in Modeling

Summary

Fundamental Concepts

Chapter 3: RDF-The Basis of the Semantic Web

Distributing Data Across the Web

Merging Data from Multiple Sources

Namespaces, URIs, and Identity

Expressing URIs in Print

Standard Namespaces

Identifiers in the RDF Namespace

Challenge: RDF and Tabular Data

Higher-Order Relationships

Alternatives for Serialization

N-Triples

Notation 3 RDF (N3)

RDF/XML

Blank Nodes

Ordered Information in RDF

Summary

Fundamental Concepts

Chapter 4: Semantic Web Application Architecture

RDF Parser/Serializer

Other Data Sources-Converters and Scrapers

RDF Store

RDF Data Standards and Interoperability of RDF Stores

RDF Query Engines and SPARQL

Comparison to Relational Queries

Application Code

RDF-Backed Web Portals

Data Federation

Summary

Fundamental Concepts

Chapter 5: RDF and Inferencing

Inference in the Semantic Web

Virtues of Inference-Based Semantics

Where Are the Smarts?

Asserted Triples versus Inferred Triples

When Does Inferencing Happen?

Inferencing as Glue

Summary

Fundamental Concepts

Chapter 6: RDF Schema

Schema Languages and their Functions

What Does it Mean? Semantics as Inference

The RDF Schema Language

Relationship Propagation through rdfs:subPropertyOf

Typing Data by Usage-rdfs:domain and rdfs:range

Combination of Domain and Range with rdfs:subClassOf

RDFS Modeling Combinations and Patterns

Set Intersection

Property Intersection

Set Union

Property Union

Property Transfer

Challenges

Term Reconciliation

Instance-Level Data Integration

Readable Labels with rdfs:label

Data Typing Based on Use

Filtering Undefined Data

RDFS and Knowledge Discovery

Modeling with Domains and Ranges

Multiple Domains/Ranges

Nonmodeling Properties in RDFS

Cross-Referencing Files: rdfs:seeAlso

Organizing Vocabularies: rdfs:isDefinedBy

Model Documentation: rdfs:comment

Summary

Fundamental Concepts

Chapter 7: RDFS-Plus

Inverse

Challenge: Integrating Data that Do Not Want to Be Integrated

Challenge: Using the Modeling Language to Extend the Modeling Language

Challenge: The Marriage of Shakespeare

Symmetric Properties

Using OWL to Extend OWL

Transitivity

Challenge: Relating Parents to Ancestors

Challenge: Layers of Relationships

Managing Networks of Dependencies

Equivalence

Equivalent Classes

Equivalent Properties

Same Individuals

Challenge: Merging Data from Different Databases

Computing Sameness-Functional Properties

Functional Properties

Inverse Functional Properties

Combining Functional and Inverse Functional Properties

A Few More Constructs

Summary

Fundamental Concepts

Chapter 8: Using RDFS-Plus in the Wild

SKOS

Semantic Relations in SKOS

Meaning of Semantic Relations

Special Purpose Inference

Published Subject Indicators

SKOS in Action

FOAF

People and Agents

Names in FOAF

Nicknames and Online Names

Online Persona

Groups of People

Things People Make and Do

Identity in FOAF

It's Not What You Know, It's Who You Know

Summary

Fundamental Concepts

Chapter 9: Basic OWL

Restrictions

Example: Questions and Answers

Adding "Restrictions"

Kinds of Restrictions

Challenge Problems

Challenge: Local Restriction of Ranges

Challenge: Filtering Data Based on Explicit Type

Challenge: Relationship Transfer in SKOS

Relationship Transfer in FOAF

Alternative Descriptions of Restrictions

Summary

Fundamental Concepts

Chapter 10: Counting and Sets in OWL

Unions and Intersections

Closing the World

Enumerating Sets with owl:oneOf

Differentiating Individuals with owl:differentFrom

Differentiating Multiple Individuals

Cardinality

Small Cardinality Limits

Set Complement

Disjoint Sets

Prerequisites Revisited

No Prerequisites

Counting Prerequisites

Guarantees of Existence

Contradictions

Unsatisfiable Classes

Propagation of Unsatisfiable Classes

Inferring Class Relationships

Reasoning with Individuals and with Classes

Summary

Fundamental Concepts

Chapter 11: Using OWL in the Wild

The Federal Enterprise Architecture Reference Model Ontology

Reference Models and Composability

Resolving Ambiguity in the Model: Sets Versus Individuals

Constraints Between Models

OWL and Composition

owl:Ontology

owl:imports

Advantages of the Modeling Approach

The National Cancer Institute Ontology

Requirements of the NCI Ontology

Upper-Level Classes

Describing Classes in the NCI Ontology

Instance-Level Inferencing in the NCI Ontology

Summary

Fundamental Concepts

Chapter 12: Good and Bad Modeling Practices

Getting Started

Know What You Want

Inference Is Key

Modeling for Reuse

Insightful Names Versus Wishful Names

Keeping Track of Classes and Individuals

Model Testing

Common Modeling Errors

Rampant Classism (Antipattern)

Exclusivity (Antipattern)

Objectification (Antipattern)

Managing Identifiers for Classes (Antipattern)

Creeping Conceptualization (Antipattern)

Summary

Fundamental Concepts

Chapter 13: OWL Levels and Logic

OWL Full versus OWL DL

Provable Models

Class/Individual Separation

InverseFunctional Datatypes

OWL Lite

Other Subsets of OWL

Beyond OWL 1.0

Metamodeling

Multipart Properties

Qualified Cardinality

Multiple Inverse Functional Properties

Rules

Summary

Fundamental Concepts

Chapter 14: Conclusions

Appendix: Frequently Asked Questions

Further Reading

Index