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1/23
Michael KleinUniversität Karlsruhe
A Process and a Tool for Creating Service Descriptions based on
DAML-S
4th VLDB Workshop on Technologies for E-Services (TES'03)
Berlin, September 8th, 2003
Michael Klein, Birgitta König-RiesInstitute for Program Structures and Data Organization
Chair: Prof. Peter C. LockemannUniversität Karlsruhe, Germany
DFG SPP 1140 DIANE Project
2/23
Michael KleinUniversität Karlsruhe
Today’s Service Discovery
1. Send simple query
keywords, boolean constraints
Service catalogue
2. Receive advertisements
Set of WSDL files
3. Choose & Configure Look through set understand meaning choose appropriate
service configure service
Human user
4. Invoke service
SOAP
UDDI
Service provider
3/23
Michael KleinUniversität Karlsruhe
Tomorrow’s Service Discovery
1. Send complex query
declarative
Service catalogue
2. Receive matchingadvertisement
Single description
3. Configure set parameters
4. Invoke service
Service provider
ontology-based
matcher
Human user
ComputerAgent
4/23
Michael KleinUniversität Karlsruhe
Automatic Service Discovery
Enrich service description with computer-interpretable semantics by
basing describing concepts on well-defined semantics (logics)
clearly expressing functional semantics
including real world knowledge into the description
Matcher has to understand the meaning description
REQUIREMENT
METHOD
5/23
Michael KleinUniversität Karlsruhe
Possible Technology: DAML-S
DAML-S Language to describe services semantically Based on DAML, frame-based ontology language
(with formal semantics from description logics)
Service
Profile declarative, blackbox, what?
prese
nts
Model procedural, glassbox, how?describes
Grounding technical access details
supports
6/23
Michael KleinUniversität Karlsruhe
DAML-S Profile
Profile
ParameterDescription
ParameterDescription
input output
ParameterDescription
ParameterDescription
precond. effect
non-functional parameters name, description, QoS, …
Allows to integrate additional ontologies for real-world knowledge flexible and extensible
7/23
Michael KleinUniversität Karlsruhe
Problem with DAML-S Profile
MAIN PROBLEM
Types of the IOPEs too generic: type “ParameterDescription” structure unclear and not unified
not automatically comparable not creatable by humans
8/23
Michael KleinUniversität Karlsruhe
Approach of the Paper
Layer ontologies dynamically.
APPROACH
preserve flexibility and extensibility by additional ontologies
AND: produce descriptions that have roughly the same structure
Details Use three layers Define tasks of each layer Support by process and tool
9/23
Michael KleinUniversität Karlsruhe
Overview over the Layering
III. Domain Ontologies Task: Define vocabulary to
describe domain specific parts thousands, distributed Examples: shoes, databases,
locations…
SQL
SELECT
Rel. Model
Rel. Algebra
UPDATE
II. Service Category Ontologies Task 1: Restrict types of the IOPEs Task 2: Defines these types exactly few (5-10) Example: InformationService
InfoState InfoState
Author TopicTitle
Document
I. Upper Service Ontology Task: Set up general structure of a
service description unique, commonly accepted, small DAML-S
Service
Prec Effect
IV. Instantiation According to the ontology but adds/omits attributes
10/23
Michael KleinUniversität Karlsruhe
I. Upper Service Ontology
GOAL
Set up a general structure of a service description.
Approach Use DAML-S and adapt Profile
Profile
Data Datainput output
State Stateprecond. effect
11/23
Michael KleinUniversität Karlsruhe
II. Service Category Ontology
GOAL
Divide space of services into categories of services with similar state transformations.
Examples InformationService:
Changes the (availability) state of a document KnowledgeService:
Changes the state concerning a piece of knowledge RealObjectService:
Changes the (possession) state of an object in the real world
Concrete Tasks (1) Specialize abstract IOPE ranges into concrete types (2) Define these types exactly
12/23
Michael KleinUniversität Karlsruhe
II. Service Category Ontologies – Task 1
Task 1: Specialize abstract IOPE ranges into concrete typesApproach: Taxonomical ontology of statesExample:
State
InformationState
Available Unavailable
LocallyAv RemotelyAv OfflineAv
StoredInRAM StoredOnHD Printed Displayed
Document entity
Locationloc
13/23
Michael KleinUniversität Karlsruhe
II. Service Category Ontology – Task 2
Task 2: Exactly define used types
Approach: For each new type, choose set to atomic type (not recommended) set to enumeration type and list instances set to concrete class type and recursively define
structure (for example by separating aspects) set to abstract class type and leave definition open for
concrete domain ontology
14/23
Michael KleinUniversität Karlsruhe
II. Service Category Ontology – Task 2, Example
Document
FORMAT
Information Topiccontains dealsWith
xsd:String Keyword
Location
dc:Format dc:Title dc:Subject
<pdf> <ps> <doc>
Printed
COLOR
xsd:integer
color
resolution
<bw>
<col>
15/23
Michael KleinUniversität Karlsruhe
III. Domain Ontologies
GOAL
Provide domain-specific vocabulary to describe abstract (real-world) parts of the description.
Concrete Tasks (1) Define the schema of the domain (2) Define concrete instances of the domain (3) Define domain specific comparison functions
Examples Seats in a certain cinema Learning Topics in Databases Locations on the Campus of the University of Karlsruhe
16/23
Michael KleinUniversität Karlsruhe
III. Domain Ontologies – Example
Simple Example: Locations on the Campus of the University of Karlsruhe
Location
CampusLocation
Room Buildingwithin
isNeighboredTo isNeighboredTo
1) 2) buildingA:Building
buildingB:Building
room335:Room
room337:Room
room14:Room
ww w
n
n
3) sim(Room r1, r2)
sim(Building b1, b2)
dist(Room r1, r2)
17/23
Michael KleinUniversität Karlsruhe
IV. Instantiating
Instantiate according to type:
atomic type enter value
enumeration type pick value from list
concrete class type pick predefined instance create new instance and instantiate the range types of
all properties abstract class type
not possible
free instantiation instantiate additional properties with unspecified domain
18/23
Michael KleinUniversität Karlsruhe
Overview of the Process
(1) Acquiring the upper ontology
(2) Choosing a category
(3) Choosing concrete states
(4) Instantiating atomic/enum. types
(5) Instantiating concrete class types
(6) Instantiating freely
(7) Concreting abstract class types if not ready
19/23
Michael KleinUniversität Karlsruhe
Complete Description Instance Example
myService:Service
:InfoServiceProfile :Printed:Locally
Available
:Document
presents
precondition effect
entity entity
dc:Format
<pdf>
color
<bw>
res.
600
location
room335:Room
20/23
Michael KleinUniversität Karlsruhe
Tool: DINST
21/23
Michael KleinUniversität Karlsruhe
Improvements of this Approach
Comparability: Description follows a common structure Still possibility to adapt to all kinds of services
category domain
Basic comparison algorithm: graph matching Special treatment
Domain specific comparision functions Declarative parts and conditions in queries
Editability: 7 steps guide user through creating process tool DINST supports this process graphically
22/23
Michael KleinUniversität Karlsruhe
Summary & Future Work
Summary DAML-S is promising description language for tomorrow’s automatic
service discovery BUT: Unusable
Structure of the IOPEs is unclear and not unified APPROACH: Layering of ontologies
3 layers, each well-defined tasks preserve flexibility/extensibility, enhance structure automatic comparison becomes possible
SUPPORT: Process and Tool
Future Configurable Service Descriptions
(submitted to SOC 2003 in Italy)
23/23
Michael KleinUniversität Karlsruhe
Thanks for your attention!
Do you have any questions?
Further information:http://www.ipd.uni-karlsruhe.de/DIANE
24/23
Michael KleinUniversität Karlsruhe
APPENDIX
25/23
Michael KleinUniversität Karlsruhe
DAML-S: Overview ServiceProfile