1/23 Michael Klein Universität 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-Ries Institute for Program Structures and Data Organization Chair: Prof. Peter C. Lockemann Universität Karlsruhe, Germany DFG SPP 1140 DIANE Project

2/23 Michael Klein Universität 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 Klein Universität Karlsruhe Tomorrow’s Service Discovery 1. Send complex query declarative Service catalogue 2. Receive matching advertisement Single description 3. Configure  set parameters 4. Invoke service Service provider ontology- based matcher Human user Computer Agent

4/23 Michael Klein Universität 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 Klein Universität 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? presents Model procedural, glassbox, how? describes Grounding technical access details supports

6/23 Michael Klein Universität Karlsruhe DAML-S Profile Profile Parameter Description Parameter Description inputoutput Parameter Description Parameter Description precond.effect non-functional parameters  name, description, QoS, … Allows to integrate additional ontologies for real-world knowledge  flexible and extensible

7/23 Michael Klein Universität 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 Klein Universität 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 Klein Universität 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 AuthorTopicTitle 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 Klein Universität Karlsruhe I. Upper Service Ontology GOAL Set up a general structure of a service description. Approach  Use DAML-S and adapt Profile Profile Data inputoutput State precond.effect

11/23 Michael Klein Universität 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 Klein Universität Karlsruhe II. Service Category Ontologies – Task 1 Task 1: Specialize abstract IOPE ranges into concrete types Approach: Taxonomical ontology of states Example: State Information State AvailableUnavailable LocallyAvRemotelyAvOfflineAv StoredInRAMStoredOnHDPrintedDisplayed Document entity Location loc

13/23 Michael Klein Universität 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 Klein Universität Karlsruhe II. Service Category Ontology – Task 2, Example Document F ORMAT InformationTopic contains dealsWith xsd:String Keyword Location dc:Formatdc:Title dc:Subject Printed C OLOR xsd:integer color resolution

15/23 Michael Klein Universität 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 Klein Universität Karlsruhe III. Domain Ontologies – Example Simple Example: Locations on the Campus of the University of K a rlsruhe Location Campus Location RoomBuilding within isNeighboredTo 1) 2) buildingA: Building buildingB: Building room335: Room room337: Room room14: Room www n n 3) sim(Room r1, r2) sim(Building b1, b2) dist(Room r1, r2)

17/23 Michael Klein Universität 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 Klein Universität 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 Klein Universität Karlsruhe Complete Description Instance Example myService: Service :InfoServiceProfile :Printed :Locally Available :Document presents precondition effect entity dc:Format color res. 600 location room335 :Room

20/23 Michael Klein Universität Karlsruhe Tool: DINST

21/23 Michael Klein Universität 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 Klein Universität 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 Klein Universität Karlsruhe Thanks for your attention! Do you have any questions? Further information:

24/23 Michael Klein Universität Karlsruhe APPENDIX

25/23 Michael Klein Universität Karlsruhe DAML-S: Overview ServiceProfile