Ontology-driven Geospatial Service Composition Using a Multiagent Framework

LAITS, GMU

Genong Yu, Liping Di, Wenli YangYue Peng, Peisheng Zhao, Aijun Chen

Center for Spatial Information Science and Systems (CSISS)

George Mason University6301 Ivy Lane, Suite #620, MD 20770

Objectives

● Use multiagent technology to fulfill the mission of geospatial service composing with local information-

● Solving geospatial problems in Web service environment normally requires invocation of a chain of geospatial services. The process of creating the chain is called geospatial web service composition. Most web service composition approaches rely heavily on a centralized directory. The discovery of agents or services depends upon the completeness of the directory. Network traffic load for the centralized directory service can grow tremendously with increasing requests and may eventually be out of capacity. Ideally the discovery and composition can be restricted to access local information.

● Use ontology● Each individual agent is autonomous with its capabilities of both a receiver and a

requester. Capabilities or services provided by each agent are conveyed with ontology internally managed and matched through Java objects and externally through standardized FIPA-SL (a semantic language).

Agent Platform & Supporting Technologies

● JADE V3.3 (http://jade.tilab.com)

● WSAI (http://wsai.sourceforge.net/index.html)

● Jakarta Tomcat (http://jakarta.apache.org/tomcat/)

● Apache jUDDI (http://ws.apache.org/juddi/)

● mySQL (http://www.mysql.com/)

● MySQL Connector/J (http://www.mysql.com/products/connector/j/)

● Apache Axis v1.3 (http://ws.apache.org/axis/)

● UDDI4J v2.0.3 (http://uddi4j.sourceforge.net/)

● WSDL4J v1.5 (http://wsdl4j.sourceforge.net/downloads/)

● Xerces v2.8.0 (http://xml.apache.org/xerces-j/)

An agent

● Each agent is only responsible for its capability and a short list of its acquaintances.

● Querying to any agent could lead to the correct answer or a chain of services given that there is a large repository of data-serving and data-processing agents.

Agent in a Society

● Publish itself in a directory - DF

● Know someone – acquaintances

● Label itself – show-off its capabilities with ontology

● Perform some function - behaviors

What are they talking about?

● FIPA - SL

● Interaction protocols– Request

– Response

– ContractNet(REQUEST

:sender ( agent-identifier :name da0@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc )) :receiver (set ( agent-identifier :name landslide@ygn999999:1099/JADE ) ) :content "((action (agent-identifier :name da0@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc)) (Geo-Produce-01 :Geo-Server (agent-identifier :name da0@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc)) :Geo-Product-01 (Geo-Product-01 :Name Landslide))))" :language fipa-sl :ontology Geo-01-ontology :conversation-id 10001 )

(REQUEST :sender ( agent-identifier :name landslide@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc ))

:receiver (set ( agent-identifier :name RMA@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc )) ( agent-identifier :name slope@ygn999999:1099/JADE ) ( agent-identifier :name dem@ygn999999:1099/JADE )

( agent-identifier :name df@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc )) ( agent-identifier :name ams@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc )) )

:content "((action (agent-identifier :name da0@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc)) (Geo-Produce-01 :Geo-Server (agent-identifier :name da0@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc))

:Geo-Product-01 (Geo-Product-01 :Name Slope))))" :language fipa-sl :ontology Geo-01-ontology :conversation-id "10001.1141101276244.input0" )

t(INFORM :receiver (set ( agent-identifier :name landslide@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc )) ) :content "((action (agent-identifier :name slope@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc))

(Geo-Produce-01 :Geo-Server (agent-identifier :name slope@ygn999999:1099/JADE :addresses (sequence http://ygn999999:7778/acc)) :Geo-Product-01 (Geo-Product-01 :Name Slope :URL http://localhost/~gyu/data/slope/out_slope.hdf))))"

:reply-with landslide@ygn999999:1099/JADE1141103434183 :in-reply-to slope@ygn999999:1099/JADE1141103434088 :language fipa-sl :ontology Geo-01-ontology :conversation-id "10001.1141103433550.input0" )

Result from their discussion

● A chain of actions to achieve some goal

Multilayer Chain

agent3->->agent21

agent31->->agent22

agent32-> ->agent11->agent23

Uniqueness

● Local information – not necessarily to access a global directory

● Up one level in composition abstraction with dialogs

Future move

● Further study will examine optimization of agent integration, semantic alignment, and interoperation of agent and web service.