Problem Definition Presented by Sushant and Alex

Overview of the problem space• Scenario• Issues

Example (plant care example)

Discussion• conclusion• open questions (find more problems!)

Outline

Questions / points on the first slides (overview) that are marked green are cover by Sagres, if the first characters are green, they are at least partially covered by Sagres.

Problem Definition Presented by Sushant and Alex

• world is full of events / information, which we sense, analyze and then react

• but the world is very complex:

Scenario

minimal configuration

‘plug and play’

fault tolerance

security

Problem Definition Presented by Sushant and Alex

Scenario (cont.)

observe

Actuatorscontrol parametersof our world

Sensorsnotice events and collect ‘data’

change

‘black box’

store and process the data

Problem Definition Presented by Sushant and Alex

Data Store

Sensors

Services

Actuators

‘black box’ Sagres?

Problem Definition Presented by Sushant and Alex

Data Store

Sensors

Services

????

??

• What data is sent, how & where is the data sent (ID + URL + data)?

• What data ‘types’ / sensors? (tmp, temp, temperature??)

• How are new sensors integrated (ID)?

• What happens if a sensor‘disappears’? (fault tolerance)

• What if that sensor ‘reappears’?

• How and where is the raw data processed (RMI, Class / local, remote)?

• How is the data stored (XML? ODBS? RDBS?)?

??

‘black box’

Problem Definition Presented by Sushant and Alex

Data Store

Services

• Where are services managed (dir service?)?

• How are the features of a service described?

• Where does a service live?

• Security issues ! (private data)

• Dependencies between services (data flow?)

• Composition of services.

• Communication among services.

• Concurrency and consistency issues

• How to handle conflicting services?

• Data sent back to the ‘Data Store’,multiple ‘Data Stores’? Where?

• Create and store an image of our complex world and keep it consistent

‘black box’

??

????

Sagres !?Sagres !?

Problem Definition Presented by Sushant and Alex

Data Store

Actuators

‘black box’ • Similar issues as with sensors,– What data is sent (protocol)?– How are new actuators

integrated (ID)?

• How do we notice, that an actuator doesn’t work anymore? (fault tolerance)

Do we have any pure actuators or does an actuator always returns it’s state?

• Different time constraints (real time tasks) - how do ‘schedule’ services?

??

Problem Definition Presented by Sushant and Alex

Sensor information• integration of different sensors, data processing, data storage,

data types ...

Data storage• data integration, distribution of data and remote accessibility,

privacy / security, consistency, concurrency ...

Services• service directory, dependencies between services,

communication among services, execution space, security, concurrency, priorities ...

Summary

Problem Definition Presented by Sushant and Alex

Application: Plant monitoring + caring service

• User’s perspective

– take care of all my plants in my house • User will

– buy plants which may come with sensors, other sensors

– subscribe to a service say www.plantcare.com

• Service will– monitor all plants and inform him of status

– may be trigger actuators to automatically take care of plants…like watering plants

Problem Definition Presented by Sushant and Alex

What does monitoring involve?

• Monitor factors affecting well being of plant– light, heat, moisture

• Identify plant and get data for a healthy plant

• Co-relate the observed data across a period of time with the “healthy plant ” data

• Inform the user– plant in living room next to window needs more water

– Graphical representation: Map of house with position of plant in it, which is clickable

Problem Definition Presented by Sushant and Alex

Raw data from sensors

Sensor specific services (to XML)

mapObject service

Plant care service

Information about plant types

DATA

STORE

User

Integrating multiple XML documents

Problem Definition Presented by Sushant and Alex

Some other issues

• Liveliness of data in Database– depends on services,plants

• Where is time stamping of data done– At sensor, or home server or data store…..

• Adapting to new sensors/services– or subscribing to mapObjects service will allow him to get a

graphical interface

– temperature sensors stops working

• Reverse path: Service to Actuators– Once you have discovered that some plant need watering how do

you discover and invoke how to water it (watering device)

Problem Definition Presented by Sushant and Alex

Open architectural issues

• What level of standardization is required by a particular architecture?

• Service discovery mechanism: – Jini, UPnP, Salutation, SDS ?

• Is direct service to service communication allowed?

• Do services update DataStore, can they delete old entries?

• DataStore implementation issues, distributed, object-oriented, relational, TSpaces

• Data integration issues?

• How Sagres can be used to address this problem?

Problem Definition Presented by Sushant and Alex

• Service Discovery– Jini (Sun), UPnP (Microsoft) ,SDS(Berkeley) ,Salutation

• Data integration– Sagres

– Tspaces

• Distributed Software Architecture– Ninja, Georgia Tech’s CyberDesk

– Distributed technologies like RMI, DCOM, CORBA

– Work at HP labs, CoolTown, Chai Server

Related work