Dr. Leo ObrstDr. Leo ObrstMITRE MITRE

Information SemanticsInformation SemanticsCenter for Innovative Computing & InformaticsCenter for Innovative Computing & Informatics

April 19, 2023April 19, 2023

Semantic Interoperability & Semantic Interoperability & Semantic Models: IntroductionSemantic Models: Introduction

2

Tightness of Coupling & Semantic Explicitness

Data

Application

Implicit, TIGHT

Explicit, Loose

1 System: Small Set of DevelopersLocal

Far

Same Process Space

Same Address Space

Same CPUSame OS

Same Programming Language

Same DBMS

Same Local Area Network

Systems of Systems

Enterprise

Community

Internet

Same Wide Area Network Client-Server

Same Intranet

Federated DBs

Data WarehousesData Marts

Workflow Ontologies

Compiling

Linking

Agent Programming

Web Services: SOAP

Distributed Systems OOP

Applets

Semantic MappingsSemantic Brokers

Looseness of Coupling

Se

ma

nti

cs

Ex

plic

itn

ess

XML, XML Schema

Conceptual Models

RDF/S, OWLWeb Services: UDDI, WSDL

OWL-S

Modal Policies

Middleware Web

Peer-to-peer

N-Tier Architecture EAI

From Synchronous Interaction to Asynchronous Communication

Performance = k / Integration_Flexibility

3

Semantic Integration Implies Semantic Composition

Simple Procedure Integration &CompositionConcatenation, alignment of calling Procedure with called procedure:

Caller: Do_this (integer: 5, string: “sales”)Called: Do_this (integer: X, string: Y)

Simple Syntactic Object Integration& CompositionAlignment of embedded interface definition language statements mapping two CORBA, Javabean objects

Simple Semantic Model, Knowledge Integration & CompositionUnification of tree or graph structures,with reasoning, simple Semantic Webontologies:

- signifies the composition operation

Complex Semantic Model, Knowledge, System Integration & Composition

Unification of complex networks of graph Structures, with complex reasoning, complex Semantic Web ontologies:

1960

1998

20052010

4

Dimensions of Interoperability & Integration

Enterprise

Object

Data

System

Application

Component

0% 100%

6 Levels o

f Inte

ropera

bility

3 Kinds of Integration

Interoperability Scale

Our interest lies here

Community

5

Ontology Spectrum

weak semanticsweak semantics

strong semanticsstrong semantics

Is Disjoint Subclass of with transitivity property

Modal Logic

Logical Theory

Thesaurus Has Narrower Meaning Than

TaxonomyIs Sub-Classification of

Conceptual Model Is Subclass of

DB Schemas, XML Schema

UML

First Order Logic

RelationalModel, XML

ER

Extended ER

Description LogicDAML+OIL, OWL

RDF/SXTM

Syntactic Interoperability

Structural Interoperability

Semantic InteroperabilityFro

m less to

more

expressive

6

Ontology Spectrum

weak semanticsweak semantics

strong semanticsstrong semantics

Is Disjoint Subclass of with transitivity property

Modal Logic

Logical Theory

Thesaurus Has Narrower Meaning Than

TaxonomyIs Sub-Classification of

Conceptual Model Is Subclass of

DB Schemas, XML Schema

UML

First Order Logic

RelationalModel, XML

ER

Extended ER

Description LogicDAML+OIL, OWL

RDF/SXTM

Syntactic Interoperability

Structural Interoperability

Semantic Interoperability

Problem: Very GeneralSemantic Expressivity: Very High

Problem: Local Semantic Expressivity: Low

Problem: GeneralSemantic Expressivity: Medium

Problem: GeneralSemantic Expressivity: High

From le

ss to m

ore expre

ssive

7

Backup

8

Ontology Spectrum

weak semanticsweak semantics

strong semanticsstrong semantics

Is Disjoint Subclass of with transitivity property

Modal Logic

Logical Theory

Thesaurus Has Narrower Meaning Than

TaxonomyIs Sub-Classification of

Conceptual Model Is Subclass of

DB Schemas, XML Schema

UML

First Order Logic

RelationalModel, XML

ER

Extended ER

Description LogicDAML+OIL, OWL

RDF/SXTM

Syntactic Interoperability

Structural Interoperability

Semantic Interoperability

Logic Spectrum will cover this area

From le

ss to m

ore expre

ssive

9

Logic Spectrum: Classical Logics: PL to HOL

less expressiveless expressive

most expressivemost expressive

Second Order Logic (SOL)

Propositional Logic (PL)

Propositions (True/False) + Logical Connectives (, , , , )

First-Order Logic (FOL): Predicate Logic, Predicate Calculus

Higher Order Logic (HOL)

PL + Predicates + Functions + Individuals + Quantifiers (, ) over Individuals

FOL + Quantifiers (, ) over Predicates

Modal Propositional Logic

Modal Predicate Logic (Quantified Modal Logic)

PL + Modal operators (, ): necessity/possibility, obligatory/permitted, future/past, etc. Axiomatic systems: K, D, T, B, S4, S5

FOL + Modal operators

SOL + Complex Types + Higher-order Predicates (i.e., those that take one or more other predicates as arguments)

Logic Programming (Horn Clauses)

Substructural Logics: focus on structural rules

Syntactic Restriction of FOL

Decidable fragments of FOL: unary predicates (concepts) & binary relations (roles) [max 3 vars]

From le

ss to m

ore expre

ssive Logics

Description Logics