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5 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Steffen Staab

ISWeb


Information Systems & Semantic Web

Semantic Management of
Web Services

Steffen Staab

Prague

May 19, 2005

Steffen Staab

ISWeb


Information Systems & Semantic Web

Hopes


Describe a goal



let the work be done by

Semantic Web Services

(previously „agents“, „PSMs“,…)



Projects like


EU: DIP, ASG, Ibrow, …


IBM India: see WWW2005


US: OWL
-
S

Steffen Staab

ISWeb


Information Systems & Semantic Web

Costs

Granularity

of Modelling

Management


Costs

coarse

fine

low

high

Hopes

SWS

RPC

WS*

Steffen Staab

ISWeb


Information Systems & Semantic Web

Costs

Granularity

of Modelling

Management


Costs

Modelling

Costs

coarse

fine

low

high

Total

Costs

Humbleness in Front of Total Costs

RPC

SWS

WS*

Steffen Staab

ISWeb


Information Systems & Semantic Web

Humbleness


What are the most urgent problems?


Where are the largest benefits


Analogy/Pseudoquote from Mohan

(Sigmod Record, 2004):

„Relational Databases were so successful, because people would have to write 20
times more code if they would not use them.

Therefore, people could do things that they were not able to do otherwise, because
they would not have been able to write 20 times more code.

Therefore, people put up with early relational database mgmt systems, which were
unstable, had many problems, etc.“

Where is this huge need for

Semantic Web Services?


Better be incremental!

Steffen Staab

ISWeb


Information Systems & Semantic Web

Hope, Humbleness and Hope again…


Web Services


Middleware

»
They are a huge mess!

»
Though they have clear conceptual underpinnings,
they are complex beasts!

»
Semantic Technologies can do something for them!


»
Let‘s backtrack how!

Steffen Staab

ISWeb


Information Systems & Semantic Web

Situation AIFB 1999



not about Web Services

Portal
1

Portal
2

Portal
3

Portal
4

Knowledge

Management

App

...

External


Internal

Semantic

Web Service x

Semantic Web

Steffen Staab

ISWeb


Information Systems & Semantic Web

Contribution of this talk


ASSW facilitates application
development in the Semantic
Web


Semantic Web technology is
used within the ASSW



Semantic Web

ASSW

helps

helps

Semantic Web

Web Services

helps

helps


Web Services facilitate
application development

(in the Semantic Web)


Semantic Web technology is
useful for Web Services

Application Server for
the Semantic Web

Steffen Staab

ISWeb


Information Systems & Semantic Web

Agenda


Application Server


Semantic Web for Application Server


Problem


Ontology


Use Cases


Development Time


Run Time


Ontology Design


Architecture


Implementation


Relationship to MDA


Conclusion


App Server for Semantic Web



Semantic Management of Web Services

Steffen Staab

ISWeb


Information Systems & Semantic Web

Complexity in Application Servers

Multitude of XML
-
DTDs

Problem

web.xml

ejb
-
jar.xml

application.xml

.htaccess

MLETs

login
-
config.xml

...

Ontology

Resources

Users

Dependencies

Access Rights

...


<web
-
app>

<
servlet
>


<servlet
-
name
>JMXInvokerServlet...


<servlet
-
class
>org.jboss....</servlet
-
class>


<init
-
param> ... </init
-
param>


<load
-
on
-
startup>1</load
-
on
-
startup>

...


<
security
-
constraint
>


...


</security
-
constraint>



<login
-
config>


<auth
-
method>BASIC</auth
-
method>


<realm
-
name>HTTP Invoker</realm
-
name>


</login
-
config>



<
security
-
role
>


<role
-
name>HttpInvoker</role
-
name>

</security
-
role>

...

Steffen Staab

ISWeb


Information Systems & Semantic Web


Ontology is explicit conceptual model


Formalizes properties, relationships and
behaviors of components



Aims at conceptualizing „shared“
understanding


Logics
-
based formal semantics


Axioms


Allows reasoning


Allows conceptual querying




Ontology

Ontology

Semantic Metadata

Schema level


Instance level

CustomerEJB

instOf

Component

EnterpriseBean

MBean

Steffen Staab

ISWeb


Information Systems & Semantic Web

Use Cases Development Time


Component dependencies and versioning






Licensing


model development constraints


Capability descriptions


make component capabilities explicit


Semantics of parameters


associate names with ontology


Automatic generation of component and service metadata


beyond java2wsdl

WebShop
-

Servlet

Customer Entity Bean

Recommender
-

Servlet

News
-

Servlet

...

...

Lib

Lib

Lib

Lib

Lib

Steffen Staab

ISWeb


Information Systems & Semantic Web

Use Cases Run Time


Access Rights


E.g. indirect permissions






Error handling


Avoid exceptions thrown to the user


Transactional settings


Discover components that do not support
transactions


Secure communication


Discover non
-
encrypting components


Customer

Anonymous

WebShop
-

Servlet

Customer Entity Bean

Admin

Context

Switch

...

Steffen Staab

ISWeb


Information Systems & Semantic Web

Ontology Design


Ontology Design


Syntactic vs. Semantic Metadata


Generic vs. Domain Knowledge


Modular

Component
Grounding
Profile
IDL
API Description
Implementation
Domain
API Description
Domain
Profiles
Generality
D
o
m
a
i
n


































G
e
n
e
r
i
c
S
e
m
a
n
t
i
c
















S
y
n
t
a
c
t
i
c
M
e
t
a
d
a
t
a
















M
e
t
a
d
a
t
a
ontology module
uses module
application.xml
web.xml
ejb-jar.xml
...
Domain Ontology Modules
Capability

Descriptions

Container

Semantics of parameters

Automatic generation

Domain Knowledge

Implementation details

Mapping to source code

Syntactic vs.

Semantics

Steffen Staab

ISWeb


Information Systems & Semantic Web

Inference

Engine


Architecture

web.xml

ejb
-
jar.xml

application.xml

.htaccess

MLETs

login
-
config.xml

...

Ontology

Application Server Core Services

Component

Loader

Security

Transaction

Manager

Naming

Administration

Security

Management

Version

Management

Steffen Staab

ISWeb


Information Systems & Semantic Web

KAON SERVER

http://kaon.semanticweb.org


Prototype of an

ontology
-
based Application Server


Part of
KArlsruhe ONtology and

Semantic Web Toolsuite

(KAON)


Uses KAON ontology language

and inference engine


Makes obsolete several description files


Uses JMX/JBossMX


Inference engine as additional MBean


Additionally facilitates development

of Semantic Web applications

[ACM TOIT 5(2)]

Steffen Staab

ISWeb


Information Systems & Semantic Web

Relationship to MDA





OMG‘s Model Driven Architecture


Separates conceptual from
implementation concerns


Not applied for run time aspects so far


Lack of formal semantics


No reasoning capability

Steffen Staab

ISWeb


Information Systems & Semantic Web

Agenda


Application Server


Semantic Web for Application Server


App Server for Semantic Web



Semantic Management of Web Services

Steffen Staab

ISWeb


Information Systems & Semantic Web

Rule-based
system
DL
reasoner
Ontology
Store
XML Schema
Validator
Ontology Editor
Person
Graduate-Student
AcademicStaff
Person
birthday
xsi:dateTime
Portal
Person Graduate-Student
AcademicStaff
cooperatesWith(Y,X)
< ->
cooperatesWith(X,Y)
Information chain
APPLICATION
USES
SOFTWARE
MODULE
Analysis


Megaprogramming









Semantic Web Layer Cake

Unicode



URI

XML + Namespaces

RDF + RDFS

Ontology

Logic

Proof

Trust

Steffen Staab

ISWeb


Information Systems & Semantic Web

1.
Flexible handling of modules

Extensibility, Dependencies, …

2.
Static part of the Semantic Web

Language Support, Ontology Mapping, …

3.
Dynamic part of the Semantic Web

Finding, Accessing, Modifying and Storing of ontologies

Transactions and Rollbacks, Evolution and Versioning, Inferencing and
Verification, …

4.
Semantic enhancement of the server

Component capability descriptions and discovery, Semantic API
descriptions, Component classification, automatic generation of
semantic web service descriptions, etc.

5.
Common Application Server functionality


Requirements

Steffen Staab

ISWeb


Information Systems & Semantic Web

Requirements in the Architecture

Language Support

Semantic Interoperability

Ontology Mapping

Ontology Modularization

Finding, Accessing, Storing

Transactions, Rollbacks

Evolution, Versioning

Inferencing, Verification

Connectivity, Security

Extensibility

Discovery

Dependencies


Design element


Requirement

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Steffen Staab

ISWeb


Information Systems & Semantic Web

Design

1.
Flexible handling of modules



Microkernel and component approach


Functionality: simple management operations


(start, stop, monitor, ...)






Modules must be instrumented
-
> components

Microkernel

. . .

Software Module
Software Module
Instrumentation
Component
Software Module
Proxy
Component
External
Module
1)
2)
Instrumentation
Steffen Staab

ISWeb


Information Systems & Semantic Web

Design

2.
Static part of the Semantic Web




functional components

3.
Dynamic part of the Semantic Web




functional components

4.
Semantic enhancement of the server




ontological registry with inference capability




system component

5.
Common Application Server functionality




Reuse existing Application Server as far as possible

Steffen Staab

ISWeb


Information Systems & Semantic Web

Architecture

Client


Surrogate
1

Surrogate
2

Steffen Staab

ISWeb


Information Systems & Semantic Web

Implementation

Application Server

for the Semantic Web

Kernel

Components

Design

KAON SERVER

MBeans

MBeanServer

Implementation

Java Mgmt Extensions (JMX)

JBossMX

Steffen Staab

ISWeb


Information Systems & Semantic Web

Starting the Server/Mgmt Console

Steffen Staab

ISWeb


Information Systems & Semantic Web

Browsing and querying the registry

KAON OIModeler


Generic KAON ontology store surrogate

Steffen Staab

ISWeb


Information Systems & Semantic Web

Browsing and querying the registry

KAON OIModeller for browsing and querying

the KAON SERVER‘s registry at run
-
time

Steffen Staab

ISWeb


Information Systems & Semantic Web

OilEd

OilEd


Reasoner surrogate

Generic RDF surrogate

1.
OilEd queries registry

for available reasoners


2.
Component ID is fed into

reasoner surrogate


3.
Reasoner surrogate relays

communication to FaCT


Steffen Staab

ISWeb


Information Systems & Semantic Web

From App Server to Web Services

ASSW Cascade

Steffen Staab

ISWeb


Information Systems & Semantic Web

Purpose of Web Services

Semantic Web

Web Services

helps


Semantic Web technology is
useful for Web Services

=

Application Server

+ Wide Distribution

+ Web Standards


Light
-
weight


Widely distributed


Heterogeneous

platforms

Steffen Staab

ISWeb


Information Systems & Semantic Web

Chasm of Web Services

Web Services Standards
WS*



RPC


I/O Typing


Workflow


Security





Plumbing

Semantic Web Services




Goals


Means





End Customer Use


Steffen Staab

ISWeb


Information Systems & Semantic Web

Chasm of Web Services

Semantic Management of Web Services

Web Services
Standards WS*



Complex by size


Complex by
heterogeneity


No coherent model


Inconsistencies

Semantic Web Services




Too complicated to
specify for developers


Semantics not
powerful enough

Steffen Staab

ISWeb


Information Systems & Semantic Web

Costs

Granularity

of Modelling

Management


Costs

Modelling

Costs

coarse

fine

low

high

Total

Costs

Modelling Cost Considerations

WS*

SWWS

Our
target

Steffen Staab

ISWeb


Information Systems & Semantic Web

Data vs Services Analogy

Data



Modelling


Query


Modify


Join

Services



Modelling


Query


Configure


Compose



Execute


Monitor


Steffen Staab

ISWeb


Information Systems & Semantic Web

Ordner A

Ordner B

File 1

File 2

DBMS

Physical
Data

Immediate
Meaning of
Data

Logical
Schema

How?

What?

Why?

Implicit
Meaning of
Data

Knowledge Discovery
remains a labor
-
intensive process!

Steffen Staab

ISWeb


Information Systems & Semantic Web

Konkrete
Definitionen
referenziert
definitions
types
messages
parts
portType
operation
binding
operation
service
port
Abstrakte
Definitionen
Web Service MS

TCP/IP

„WS
-
Policy“, ….

WSDL,
BPEL, …

How?

What?

Why?

(automatic
composition!)

Semantic
Web
Services

Service organisation will
remain a labor
-
intensive
process!

Steffen Staab

ISWeb


Information Systems & Semantic Web

Conclusion from analogy

Modelling and use of Web services by
manipulation of individual files is an archaic
practice


just like managing data by reading
and writing individual files!

Steffen Staab

ISWeb


Information Systems & Semantic Web

WS Management Objectives


Separate „What?“ from „How?“



Leave „Why?“ to the developer

(at least for the moment)



Go beyond simple data manipulation into
semantic management in order to capture
the immediate meaning of Web services

Steffen Staab

ISWeb


Information Systems & Semantic Web

Use Cases

Who?

What for?

When?

Query type/Service Mgmt Task?

Steffen Staab

ISWeb


Information Systems & Semantic Web





DOLCE




Descriptions & Situations





Ontology of Plans




Core Ontology of Services



Service Management Core Ontology




Domain ontologies

Ontologies for an Open World

Steffen Staab

ISWeb


Information Systems & Semantic Web

D&S alignment to DOLCE

Ground entities of DOLCE

Descriptive entities of D&S

Description

S
-
Description

Situation

played
-
by

satisfies

C
-
Description

Functional Role

Course

Parameter

component

In the following slides we
see some modelling
excerpts from the different
levels…

Steffen Staab

ISWeb


Information Systems & Semantic Web

COS alignment to D&S

DOLCE

D&S

COS

Description

S
-
Description

Situation

Functional Role

Course

Service Assessment

Description

Service Offering

Description

Service Requirements

Description

Service Activities

Description

Service Agreement

Description

Activity

Service Activity

Computational Activity

Agentive

Functional Role

Instrumentality

Role

Legally Constructed Person

Executor

Requestor

Provider

Input

Output

Computational Input

Comp. Output

Task

Service Task

Computational Task

Information

Object

Conceptual disambiguation

Wider scope

Steffen Staab

ISWeb


Information Systems & Semantic Web

Service Management Core
Ontology

Description

Set of descriptive

concepts and associations

Association

Descriptive

Concept

Service Management Description

Information

Source

Age of

Information

Parameter

Parameter

...

...

Quality of Service Descrip.

Plan Description

Interface Description

Policy Description

Metadata from: WSDL, WS
-
policy, performace measurements, reflection

Steffen Staab

ISWeb


Information Systems & Semantic Web

Policy Description

Situation

Descriptive Entities

Ground Entities

Computational

Activity

Perdurant

(non
-
agentive)

Functional Role

Information

Object

Endurant

Task

Course of Event

participant

Constraint

valued
-
by

Constraint Value

obligation towards

anakastic
duty

towards

requisite for

Concrete

Constraint

User

(agentive)

Functional Role

sequences

right

played
-
by

Object

Information

Object

Endurant

Parameter

played
-
by

Policy

Constraint

Constraint Value

participant

locatedIn

Steffen Staab

ISWeb


Information Systems & Semantic Web

Service Management Description
SMD
1

Interface Description
ID
1


Operation
Op
1


Computational

Input
CI
1


Computational

Output
CO
1

Service Management Description
SMD
2

Interface Description
ID
2


Operation
Op
2


Computational

Input
CI
2


Computational

Output
CO
2

<BPEL>

<WSDL>

<WSDL>

Steffen Staab

ISWeb


Information Systems & Semantic Web

Integration in KAON Server

Steffen Staab

ISWeb


Information Systems & Semantic Web

Conclusion on Semantic Middleware


Ontologies provide great practical benefit



Conceptual difference between components and
web services are marginal (see Oberle 2005)



Ontologies are no silver bullet!


Problem: provision of semantic metadata

-
> small is beautiful!

-
> beautiful is cheap!



Steffen Staab

ISWeb


Information Systems & Semantic Web

Thank You!


D. Oberle, A. Eberhart, S. Staab, R. Volz. Developing and Managing
Software Components in an ontology
-
based Application Server. In
Proc. Middleware 2004, ACM/IFIP/USENIX International Middleware
Conference
, Toronto, October 18
-
22, 2004, LNCS, Springer.



D. Oberle, S. Staab, R. Studer, R. Volz. Supporting Application
Development in the Semantic Web.
ACM Transactions on Internet
Technology
, 5(2), 2005.



D. Oberle, S. Lamparter, A. Eberhart, S. Staab. Semantic
Management of Web Services. Tech Report (shorter version at
Semantic Web Service Week, Innsbruck June 2006).



D. Oberle. Semantic Management of Middleware. Springer 2005/06



http://isweb.uni
-
koblenz.de/

Steffen Staab

ISWeb


Information Systems & Semantic Web

Web services constitute a middleware in order to model
distributed applications and let them run on a set of
heterogeneous platforms.

Unfortunately, the many different Web service standards
do not include a formal, let alone a common formal,
model, which would allow to give an integrated,
consistent view onto all of them.

In this talk we sketch how ontologies may be used to
integrate metadata about middleware in general and web
services, in particular. Thus, we may answer about
properties of web services in order to facilitate the life of
the system developer and administrator for

managing complex, distributed systems.