Transcript Presentation`s Slides

DBGlobe: A Data Centric
Approach to Global Computing
3rd Meeting
Athens, November 29, 2002
George Samaras
Chara Skouteli
UCY
Context Aware Applications
How we define “context”
Context is any information that can be used to
characterize the situation of an entity.[1]
An entity is
 a person,
 place,
 or object
that is considered relevant to the interaction between a user and an
application, including the user and application themselves.
Context Information
Almost any information available at the time of an interaction can be seen as
context information. Some examples are:
 identity
 spatial information - e.g. location, orientation, speed, and acceleration
 temporal information - e.g. time of the day, date, and season of the year
 environmental information - e.g. temperature, air quality, and light or noise
level
 social situation - e.g. who you are with, and people that are nearby
 resources that are nearby - e.g. accessible devices, and hosts
 availability of resources - e.g. battery, display, network, and bandwidth
 physiological measurements - e.g. blood pressure, hart rate, respiration
rate, muscle activity, and tone of voice
 activity - e.g. talking, reading, walking, and running
 schedules and agendas
Challenges
 Capture
 Inputs from system
 Inputs from devices
 Inputs from users
 Represent
 Use of xml schema
 Efficient taxonomy
 Process contextual data
 Queries on metadata
 Data Mining
 Create or discover a relationship between them
Context-Aware Applications
Find nearby resources.
 This can include input and output devices:
 printers, displays, speakers, facsimiles, video
cameras, thermostats, etc.
location information of the client is required.
Create local network communities.
Obtain regional information in the ad-hoc
network.
DBGlobe: proof –of- content Prototype
The innovative features of our prototype
include working example of
Concept of the “ad-hoc” databases
Use of metadata to include location and user
preferences in dynamic query processing
Co-ordination and co-operation of autonomous
entities.
Information Discovery and Querying
Global Communicator Middleware
 Defines the communication level between
context-aware applications and DBGlobe system
 Provides:
Access to DataHandler
Access to Available Services of the DBGlobe System
Disconnection Support
Application Data sharing between context-aware
applications
Caching
 Should this middleware be part of the DBGlobe
system??
Communication Flow
PMO
Ad-hoc database
PMO
PMO
PMO
proxy
Application Proxy
Application
Interface
Modules
DH
Application
Function
Modules
DataStore
DH
DataStore
proxy
Ad-hoc database
PMO
Global Communicator
Middlware
PMO
PMO
Global Communicator
middleware
Communicator
Application interface module
Dynamic Query Results
Finds the location of remote objects
Gives a reference to the appropriate
Application specific modules
object. Function Modules
Application
UserAgent
Represents user in the application
Global Communicator middleware
Keeps metadata information about
UserAgents
Application
Communities
user
metadata
Disconnection support
Communities
Communicator
can be divided to several categories
and user can join them.
Interface Queries
Modules
Results
“Database” to temporarily store search
results of a query
Flow Control Units
DBGlobe access points
Service Executor
Directory
Storage Managers
Application Metadata
Query Processing
“Database” which holds
metadata for
DataStore
Server Components
users or devices necessary for the
application.
Applications
Suggested proof of content prototype :DB-Communicator
 DB-Communicator
 With DB-Communicator users will be able to:
 Search for data in DBGlobe system (information discovery and
querying)
 Create communities or join communities (concept of ad-hoc
database)
 To share data with other people who join the community (coordination and cooperation with autonomous entities)
 To define dynamic request according to their “context” information
• Push data
• Pull data
 “favorite services” (service discovery)
 Make request for a service
 Easy to extend by using the available services of the DBGlobe
system.
Communication Flow: Request for a
service
PMO
Ad-hoc database
PMO
PMO
PMO
proxy
DB-Communicator Proxy
Application
Interface
Modules
DH
Application
Function
Modules
DataStore
DH
DataStore
proxy
Ad-hoc database
PMO
Global Communicator
Middlware
PMO
PMO
Application Paradigm:Spotme!
Main functionality:
Locate my friends and let me communicate with
them
Aims to show the capability of DBGlobe system
to find services and provide them to
applications.
Communication Flow
PMO
PMO
Spotme Proxy
Ad-hoc database
PMO
PMO
proxy
Application
Interface
Modules
Application
Function
Modules
DH
DataStore
DH
DataStore
proxy
Global Communicator
Middlware
Application users
Ad-hoc database
PMO
PMO
PMO
Engineering Issues
 For remote access to objects we use voyager
platform
 In order to step forward we need the main
modules API
Login/Registatration
Service Description Method
Service Communication Method
DataHandler interface
PMOs coordination mechanism
Interface Module API
Publications under DBGlobe
[2] G. Samaras, C. Spyrou, E. Pitoura, “View Generator (VG): A Mobile Agent
Based System for the Creation and Maintenance of Web Views”, 7th IEEE
Symposium on Computers and Communications, Taormina, Italy July 2002.
[3] George Samaras, Constantinos Spyrou, Evaggelia Pitoura, Marios
Dikaiakos, “Tracker: A Universal Location Management System for Mobile
Agents.” Proc. The European Wireless 2002 Conference, Next Generation
Wireless Networks: Technologies, Protocols, Services and Applications, pp.
572-580, Florence, Italy, February 25-28, 2002.
[4] George Samaras, Christoforos Panayiotou, "A Flexible Personalization
Architecture for Wireless Internet Based on Mobile Agents", Proc. 6th EastEuropean Conference on Advances in Databases and Information Systems
(ADBIS 2002), September 2002, Bratislava, Slovakia.
[5] George Samaras, Christoforos Panayiotou, “Wireless Portals for the Mobile
User", ICDEE 2003, Demo
References
[1]
Mari Korkea-aho “Context-Aware
Applications Survey” ,Helsinki University
of Technology , 2000
Thank you!!!
Merry Christmas