View
29
Download
0
Category
Preview:
DESCRIPTION
Semantic Management of Web Services. Steffen Staab Prague May 19, 2005. 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. Hopes. Costs. high. RPC. WS*. - PowerPoint PPT Presentation
Citation preview
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
ModellingCosts
coarse fine
low
high TotalCosts
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
Portal1 Portal2
Portal3
Portal4
KnowledgeManagementApp
...
External
Internal
SemanticWeb 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 ServersMultitude of XML-DTDs
Problem
web.xml
ejb-jar.xml
application.xml
.htaccessMLETs
login-config.xml
...
OntologyResourcesUsers
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
WebShop-Servlet
Customer Entity Bean
Recommender-Servlet
Recommender-Servlet
News-Servlet
News-Servlet
...
...Lib
Lib
LibLib
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
WebShop-Servlet
Customer Entity Bean
Admin
ContextSwitch
...
Steffen Staab
ISWeb – Information Systems & Semantic Web
Ontology Design Ontology Design
– Syntactic vs. Semantic Metadata– Generic vs. Domain Knowledge– Modular
C om p on e n t
G ro u n d in gP r o f i le
ID L
A P I D esc r ip t io n
Im p lem e n ta tio n
D o m a inA P I D esc r ip t io n
D o m a in P r o f i le s
G e ne ra lity
Dom
ain
G
ener
ic
Semantic Syntactic
Metadata M
etadata
ontology moduleuses module
app lica tion.xm lw eb .xm lejb -ja r.xm l...
D o m a in O n to log y M o du le s
CapabilityDescriptions
Container
Semantics of parametersAutomatic generation
Domain Knowledge
Implementation detailsMapping to source code
Syntactic vs.Semantics
Steffen Staab
ISWeb – Information Systems & Semantic Web
InferenceEngine
Architecture
web.xml
ejb-jar.xml
application.xml
.htaccessMLETs
login-config.xml
...
Ontology
Application Server Core Services
ComponentLoader
Security
TransactionManager
Naming
Administration
SecurityManagement
VersionManagement
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 -b a se dsyste m
DLre a sone r
O nto lo g ySto re
XM L Sc he m aVa lid a to r
O nto log y Ed ito rPe rso n
G ra d ua te -Stud e nt Ac a d e m ic Sta ff
Pe rso n
b irthd a y
xsi:d a te Tim e
Porta l
Pe rso n G ra d ua te -Stud e nt Ac a d e m ic Sta ff
c o o p e ra te sWith(Y,X) < -> c o o p e ra te sWith(X,Y)
Info rm a tio n c ha in
APPLIC ATIO N
USES
SO FTWAREM O DULE
Analysis• Megaprogramming
• Semantic Web Layer Cake
Unicode URIXML + Namespaces
RDF + RDFS
OntologyLogic
ProofTrust
Steffen Staab
ISWeb – Information Systems & Semantic Web
1. Flexible handling of modulesExtensibility, Dependencies, …
2. Static part of the Semantic WebLanguage Support, Ontology Mapping, …
3. Dynamic part of the Semantic WebFinding, Accessing, Modifying and Storing of ontologiesTransactions and Rollbacks, Evolution and Versioning, Inferencing and Verification, …
4. Semantic enhancement of the serverComponent 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 Con
nect
ors
xxxxx
x x xx
x
x
Ker
nel
Reg
istr
y
Com
pone
ntL
oade
r
Ass
ocia
tion
Man
agae
men
t
Inte
rcep
tors
Func
tion
alC
ompo
nent
s
xxxx
xx x
x xx
Steffen Staab
ISWeb – Information Systems & Semantic Web
Design1. Flexible handling of modules
→ Microkernel and component approach
Functionality: simple management operations (start, stop, monitor, ...)
Modules must be instrumented -> components
Microkernel
Compo
nent
. . .
So ftwa re M o d ule So ftwa re M o d uleInstrum e nta tio n
C o m p o ne nt
So ftwa re M o d ule Pro xyC o m p o ne nt
Exte rna lM o d ule
1)
2)Instrum e nta tio n
Steffen Staab
ISWeb – Information Systems & Semantic Web
Design2. 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
ArchitectureClient
Surrogate1 Surrogate2
Steffen Staab
ISWeb – Information Systems & Semantic Web
Implementation
Application Serverfor the Semantic Web
KernelComponents
Design
KAON SERVER MBeans MBeanServer
Implem
entation
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 OIModelerGeneric KAON ontology store surrogate
Steffen Staab
ISWeb – Information Systems & Semantic Web
Browsing and querying the registryKAON OIModeller for browsing and querying the KAON SERVER‘s registry at run-time
Steffen Staab
ISWeb – Information Systems & Semantic Web
OilEdOilEd
Reasoner surrogateGeneric RDF surrogate
KAO
N RD
F st
ore
S
esam
e
FaCT
Race
r
1. OilEd queries registryfor available reasoners
2. Component ID is fed intoreasoner surrogate
3. Reasoner surrogate relayscommunication 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 ServicesSemantic 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
ModellingCosts
coarse fine
low
high TotalCosts
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
KonkreteDefinitionen
referenziert
definitions
types
messagesparts
portTypeoperation
bindingoperation
serviceport
AbstrakteDefinitionen
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 DOLCEGround entities of DOLCEDescriptive entities of D&S
Description
S-Description
Situation
played-by
satisfiesC-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&SDOLCED&SCOS
Description
S-Description
Situation
Functional Role Course
Service AssessmentDescription
Service OfferingDescription
Service RequirementsDescription
Service ActivitiesDescription
Service AgreementDescription
Activity
Service Activity Computational Activity
AgentiveFunctional Role
InstrumentalityRole
Legally Constructed Person Executor
Requestor Provider
Input Output
Computational Input Comp. Output
Task
Service Task
Computational Task
InformationObject
Conceptual disambiguation
Wider scope
Steffen Staab
ISWeb – Information Systems & Semantic Web
Service Management Core Ontology
Description Set of descriptiveconcepts and associations
AssociationDescriptiveConcept
Service Management DescriptionInformation
Source
Age of InformationParameter
Parameter
......
Quality of Service Descrip.
Plan Description
Interface DescriptionPolicy Description
Metadata from: WSDL, WS-policy, performace measurements, reflection
Steffen Staab
ISWeb – Information Systems & Semantic Web
Policy Description
Situation
Descrip
tive En
titiesG
roun
d E
ntities
ComputationalActivity
ComputationalActivity
Perdurant
(non-agentive)Functional Role
InformationObject
InformationObject
Endurant
Task
Course of Event
participant
Constraint
valued-by
Constraint Value
obligation towardsanakastic duty towards
requisite for
ConcreteConstraint
ConcreteConstraint
User
(agentive)Functional Role
sequences
right
played-by
Object
InformationObject
InformationObject
Endurant
Parameter
played-by
Policy Constraint
Policy ConstraintConstraint Value
participant
locatedIn
Steffen Staab
ISWeb – Information Systems & Semantic Web
Service Management Description SMD1
Interface Description ID1
Operation Op1
Computational Input CI1
Computational Output CO1
Service Management Description SMD2
Interface Description ID2
Operation Op2
Computational Input CI2
Computational Output CO2
<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.
Recommended