1. Information Services for Dynamically Assembled Semantic Grids
5/3/2019
Information Services for Dynamically Assembled Semantic Grids
Mehmet S. Aktas, Geoffrey C. Fox, Marlon Pierce
Community Grids Laboratory, INDIANA UNIVERSITY
The First International Conference on Semantics, Knowledge and Grid – SKG 2005, Beijing, China
SKG-05, Beijing

2. Context as Service Metadata
5/3/2019
Context as Service Metadata
Context is metadata associated to both services and their activities
Context can be
independent of any interaction
slowly varying, quasi-static context
generated as result of interaction
dynamic context
Example: information associated to an activity or session
Gaggles: Collection of Services that
are set of actively collaborating managed services for a particular common goal
generate events as result of interactions
are very small part of the whole Grid
5/3/2019
SKG-05, Beijing
SKG-05, Beijing

3. Motivating Scenario: Pattern Informatics (PI) in a Grid Environment
5/3/2019
Motivating Scenario: Pattern Informatics (PI) in a Grid Environment
PI in a Grid environment:
Hotspot forecasts are made using publicly available seismic records.
Southern California Earthquake Data Center
Advanced National Seismic System (ANSS) catalogs
Code location is unimportant, can be a service through remote execution
Results need to be visualized, stored, shared, modified
Grid/Web Services can provide these capabilities
5/3/2019
SKG-05, Beijing
SKG-05, Beijing

4. PI GIS GRID Support for slowly varying, quasi-static metadata
5/3/2019
PI GIS GRID 2
WMS
WFS
HP Search
Data Filter
PI Code 3
5,6,7 4
WMS Client 1
Support for slowly varying, quasi-static metadata
How do we support both prescriptive and descriptive metadata?
How do we enforce up-to-date information in registries?
Support for dynamic session related metadata
How do we manage dynamic workflows?
How do we enable correlation of service activities?
Information Requirements in PI GIS Grid
5/3/2019
SKG-05, Beijing
SKG-05, Beijing

5. Context Information Services Motivations
Need to provide information describing services independent of their interactions.
generic and domain specific characteristics of services
Need to manage all information associated with services for;
correlating activities of widely distributed services
enabling uniform query capabilities to both conversation-based or monolog context information
“Give me list of services satisfying C:{a,b,c..} QoS requirements and participating S:{x,y,z..} sessions”
management of events especially in multimedia collaboration
providing information to enable
session failure recovery capabilities
5/3/2019
SKG-05, Beijing

6. Problem Statement What is a novel process of building
5/3/2019
Problem Statement
What is a novel process of building
Information Services for both dynamic,
session related and slowly varying, static
context of widely distributed services
in Gaggles?
What is problem statement for this research?
5/3/2019
SKG-05, Beijing
SKG-05, Beijing

7. What is WS-Context? Repository of Context Information Allows for
Sharing Context info: metadata related to a particular transaction in multiple Web Service interactions
Sharing data: data in multiple Web service interactions
Nicely put, its a Distributed Variation of Shared Memory
Context Information dependent on the type of activity
Identify a transaction coordinator
Recovery information in event of a failure
Sharing info between participants (Security tokens, certificates, transaction IDs…)
5/3/2019
SKG-05, Beijing

8. Architectural Design Requirements
Uniformity
need consistent interface to both static and dynamic context
Interoperability
need to leverage existing WS standards (UDDI, WS-Context) for service discovery and communication
Persistence
need to provide high availability of information
Dynamism
need to handle metadata based on changing user demands
Performance
need to support dynamic changes with min. delay
5/3/2019
SKG-05, Beijing

9. The Architecture of Context Information Service
WSDL
Extended
UDDI Registry
Service
HTTP
WSDL
Database
Access NB
Node
JDBC
Expeditor
Querying
Publishing
and
Storage
Sequencer
WSDL
HTTP(S)
Client
WSDL
Client
WSDL
Client
WSDL
5/3/2019
SKG-05, Beijing

10. Fault Tolerant High Performance Information Services (FTHPIS)
Performance, compatibility, uniform interface
caching
Expeditor Module using Tuple Spaces paradigm
web service based programming interface, UDDI & WS-Context
Querying and Publishing Modules
From single point of failure to distributed system: fault tolerance
dynamic replication
Access Module
Storage Module
multi-publisher multicasting messaging
NaradaBrokering (
5/3/2019
SKG-05, Beijing

11. Distributed Dynamic Context Management
Computer Boundaries
WSDL
Extended
UDDI Registry
Service
Gaggle Boundaries A
HTTP(S)
Storage
Access
Database
WSDL
JDBC
Expeditor NB
Node
Querying
Publishing
and
Sequencer C
HTTP(S) B
Client
WSDL
NB plays role is for fast and
reliable multi-publisher, multicast
messaging among peer IS Services
5/3/2019
SKG-05, Beijing

12. SOAP header for Context 3 WMS WFS HP Search Data Filter PI Code
HP Search
Data Filter
PI Code
Context Information Service 4
7,8,9 10 6
5,11
WMS Client
Extended UDDI 1 2
5/3/2019
5,6: WMS starts a session, invokes HPSearch to run workflow script for PI Code with a session id
7,8,9: HPSearch runs the workflow script and generates output file in GML format (& PDF Format) as result
10: HPSearch writes the URI of the of the output file into Context
11: WMS polls the information from Context Service
12: WMS retrieves the generated output file by workflow script and generates a map
<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="
<soap:Header encodingStyle=“URL" mustUnderstand="true">
<context xmlns=“ctxt schema“ timeout="100">
<context-id>http..</context-id>
<context-service> http.. </context-service>
<context-manager> http.. </context-service>
<activity-list
mustUnderstand="true" mustPropagate="true">
<p-service>
<p-service>
</activity-list>
</context>
</soap:Header>
SOAP header
for Context
<context xsd:type="ContextType"timeout=“100">
<context-service> context-service>
<parent-context>
<content> shared data for HPSearch activity </content>
<activity-list mustUnderstand="true" mustPropagate="true">
<service>
<service>
<service>
</activity-list>
</context>
activity
<context xsd:type="ContextType"timeout=“100">
<context-service> context-service>
<activity-list mustUnderstand="true" mustPropagate="true">
<service>
<service>
</activity-list>
</context>
session
<context xsd:type="ContextType"timeout=“100">
<context-id>
<context-service> context-service>
<content>
</context>
shared state
<context xsd:type="ContextType"timeout=“100">
<context-service> context-service>
<parent-context>
<content> profile information related WMS </content>
</context>
user profile
The Pattern Informatics GIS-SOA based workflow application
<context xsd:type="ContextType"timeout=“100">
<context-service> context-service>
<content> HPSearch associated additional data generated during execution of workflow. </content>
</context>
service associated
5/3/2019
SKG-05, Beijing
SKG-05, Beijing

13. System Status - I Extended UDDI Metadata Service
OGC (Open Geographic Information Systems (GIS) Consortium) specific service registry, up-to-date registry entries, metadata oriented query capabilities and XPATH query capabilities..
Status: 100 % completed.
Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid (LANL)
WS-Context Complaint Metadata Services
WS-Context compatibility, support for shared dynamic context
Status: 100 % completed.
Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid
5/3/2019
SKG-05, Beijing

14. System Status - II Unified UDDI & WS-Context Metadata Services
Both WS-Context and UDDI compatibility, uniform programming interface to dynamic & static metadata, caching (high performance), support for session-failure recovery capabilities
Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid, Global MMCS project
5/3/2019
SKG-05, Beijing

15. Conclusions & Future Work
There may be following gaps in Semantic/Traditional Grid Information Services.
need for management of widely distributed, shared session-related dynamic metadata
need for enabling session failure recovery
need for uniform search interface to both interaction independent and conversation-based context
We introduce a novel architecture addressing these gaps by taking into account;
efficient metadata access and storage, decentralized fault tolerant storage capability, uniform interface to context, minimum response latency
We plan on investigating research issues related with fault tolerance and consistency as future work. We also want to evaluate the system as whole through extensive performance tests.
5/3/2019
SKG-05, Beijing

16. Location of information and software for dependent Grid Projects
5/3/2019
Location of information and software for dependent Grid Projects
htpp:// provides Web service (and JMS) compliant distributed publish-subscribe messaging (software overlay network)
is an OGC (open geospatial consortium) Geographical Information System (GIS) compliant GIS and Sensor Grid.
has WS-Context, Extended UDDI etc.
5/3/2019
SKG-05, Beijing
SKG-05, Beijing