1 Coupled Signature and Specification Matching for Automatic Service Binding Michael Klein Universität Karlsruhe (TH) Birgitta König-Ries TU München/Universität Karlsruhe (TH)

2 Motivation (mobile) Application Location print(String doc) void print(String doc, Location loc) String printNext() boolean print(URL url, Resolution res, int roomNr) void printNextWeek(String doc) boolean print(String doc, int startPage, int endPage) void print(String text, Location loc) boolean elephant(String giraffe, int zebra) ?  Which service provider to use?  How to bind the parameters?

3 Aim and Challenges Automatic, semantic service binding Goal  Service descriptions that capture semantics and message flow  Ability to automatically match service offers and requests Prerequisites

4 Service Descriptions (1) :Profile :Document Printed effect :Document LocallyAvailable precondition input PrintRequest Message s : String PrintResponse Message location : Location output Location print(String s) Prints file s on a printer nearby and returns the location of the printer Prints the file „testpage.ps“on printer s and returns the office number of the sysadmin. Identical Description! :Service presents

5 Service Descriptions (2) :Profile :Document Printed effect :Document LocallyAvailable precondition input PrintRequest Message s : String PrintResponse Message location : Location output Location print(String s) void print(String text, Location loc) :Profile :Document Printed effect :Document LocallyAvailable precondition input PrintRequest Message text : String loc: Location

6 Our Approach to Service Description  Fully state based service descriptions with  Offers describing one service instance  Requests describing sets of admissable services  Concepts to achieve this  Object sets  Variables  Possibility to match requests and offers with differing interfaces

7 Object Sets  Type dc cs Property conditions Object set tcs ms Members of an object sets are all instances of a class meeting the conditions

8 Object Sets  Type dc cs Property conditions Object set tcs ms  Type Check Strategy  Allows or disallows members of the set to belong to sub- or superclasses of the specified type

9 Object Sets  Type dc cs Property conditions Object set tcs ms  Direct conditions  Conditions on the values of the objects in the set  Property conditions  Conditions on the properties of the objects in the set

10 Object Sets  Type dc cs Property conditions Object set tcs ms  Connecting Strategy  Specifies how individual property conditions should be combined

11 Object Sets  Type dc cs Property conditions Object set tcs ms  Missing strategy  Specifies how missing property conditions should be treated

12 Variables Type dc cs Property conditions Object set tcs ms  Category  IN (to be filled in by the requestor)  OUT (to be filled in by the offerer) cat default value

13 A Service Offer entity Resolution default = 600 dpi resolution String url effect precondition Room in {room335, room336} location IN presents :Service :Profile :LocallyAvailable Printed Document IN

14 A Service Request entity String == url effect Room location OUT presents :Service :Profile Printed min(entity,room, color) Document IN within Building ==geb50.34 color Color ==bw color + -

15 Matching (mobile) Application Location print(String doc ) entity String == url effect Room location OUT presents :Service :Profile Printed min(entity,room, color) Document IN within Building ==geb50.34 color Color ==bw color + -

16 Matching Service Provider X (mobile) Application Location print(String doc ) void print(URL url, Resolution res, int roomNr) Basically: graph matching entity Resolution default = 600 dpi resolution String url effect precondition Room in {room335, room336} location IN presents :Service :Profile :LocallyAvailable Printed Document IN entity String == url effect Room location OUT presents :Service :Profile Printed min(entity,room, color) Document IN within Building ==geb50.34 color Color ==bw color + -

17 Matching effect presents :Service :Profile Printed min(entity,room, color) effect precondition presents :Service :Profile :LocallyAvailable Printed

18 Matching effect presents :Service :Profile Printed min(entity,room, color) effect precondition presents :Service :Profile :LocallyAvailable Printed Request: set, Offer: instance: Aim: determine, whether offer instance is a member of request set  type (r) = type(o)?  direct Conditions?  property Conditions?

19 Matching effect presents :Service :Profile Printed min(entity,room, color) effect precondition presents :Service :Profile :LocallyAvailable Printed as before

20 Matching entity Room location OUT Printed min(entity, room,color) Document IN color Color ==bw color + - entity Resolution default = 600 dpi resolution Room in {room335, room336} location IN Printed Document IN ´resolution as before to check property conditions, take  connecting strategy and  missing strategy

21 Matching String == url Document IN String url Document IN as before aim: determine, whether the intersection of the two sets is non-empty

22 Matching String == url Document IN String url Document IN as before check direct condition assign appropriate value to the IN variables

23 Matching as before check property condition, use ontology to determine match assign value from the intersection to the variables Room in {room335, room336} location IN Room location OUT within Building ==geb

24 Matching color Color ==bw color + no match missing strategy +: assume fulfilled

25 Completing Offer IN Variables entity Resolution default = 600 dpi resolution String url effect precondition Room in {room335, room336} location IN presents :Service :Profile :LocallyAvailable Printed Document IN

26 Critical Cases Set or OUT-Variable -missing- Request Offer additionally for OUT-Variable out OUTIN instance basic matching How many values from o are also in r? all: true some: (missing) none: false How many values from o are also in r? none: false else: assign common value to o Use missing strategy matching result: true: assign o to r false: assign null to r matching result: true: connect o and r neutral: assign o later false: assign null to r matching result: true: assign x to r false: assign null to r assign null to r

27 Summary  Semantic, dynamic service binding possible with  state based descriptions for service offers and requests with object sets and variables  automatic matching

28 Summary  Semantic, dynamic service binding possible with  state based descriptions for service offers and requests with object sets and variables  automatic matching  Unfortunately, things aren‘t quite as easy as I tried to make you believe …  Necessary to deal  with fuzzy user preferences  ….  Current work takes this into consideration  Extended matcher is being implemented right now

29 THANK...for your attention! S

30 Motivation: Dynamic Service Binding (mobile) Application Location print(String doc) Service Provider A Location print(String doc) Service Provider B Location print(String doc) Service Provider C Location print(String doc)

31 Service Descriptions (1) Foundation: Ontologies Location RoomBuilding within room2.14:Roomroom335:Roomgeb50.34:Building within Schema Instances