Sensor Intensive Web Service Architecture

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Sensor Intensive Web Service Architecture

• Senthil Ayyasamy

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Outline

• Introduction
• Resource constrained Sensor motes
• Resource Intensive Sensor Networks
• Sensor based services
• Issues and Tasks
• What is done .etc..

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Vision

• Embed numerous distributed devices to monitor
  and interact with physical world
• Exploit spatially and temporally dense, in situ,
  sensing and actuation

• Network these devices so that they can
  coordinate to perform higher-level tasks.
• Requires robust distributed systems of hundreds
  or thousands of devices.

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Introduction

• Sensor Networkslow-cost, rapid deployment,
  self-organizing, and fault tolerance.
• Application areas heath, military, and home.
• Large number of sensor nodes that are densely
  deployed.
• Nodes use their processing abilities to locally
  carry out simple computations and transmit the
  required and partially processed data.
• Ad hoc networks are not suitable for the sensor
  networks because of their unique features and
  application requirements.

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Communication Architecture
Internet and Satellite
Sink
C
D
A
E
B
Task manager node
Sensor nodes
Sensor field
User
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Design Factors

• Fault Tolerancethe ability to sustain sensor
  network functionalities without any interruption
  due to sensor node failures because of lack of
  power, physical damage, or environmental
  interference.
• Scalabilitythe density of sensor nodes can range
  from few sensor nodes to few hundred sensor nodes
  in a region.
• Production Coststhe cost of sensor node should
  be much less than 1 in order for the sensor
  network to be feasible

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Hardware Constraints
Continue.. Design Factors
Location finding system
Mobilizer
Sensing Unit
Processing Unit
Transceiver
Processor
Sensor
ADC
Storage
Power Unit
Power generator
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Continue.. Design Factors

• Sensor Network Topology- Predeployment and
  deployment phase- Post-deployment phase-
  Redeployment of additional nodes phase
• Environmentcan work in different environments.
• Transmission Medialinks between nodes can be
  formed by radio, infrared, or optical media.
• Power Consumptionbattery lifetimedesign of
  power-aware protocols and algorithmsPower
  consumption sensing, communication, and data
  processing

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Experimental Infrastructure

• Hardware
• UCB motes
• Programming
• TinyOS
• Query processing
• TinyDB
• Directed diffusion
• Geographic hash tables
• Power management
• MAC protocols
• Adaptive topologies

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Applications
Scientific eco-physiology, biocomplexity mapping
Infrastructure Contaminant flow monitoring
Engineering adaptive structures
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So, motes are for
The flexibility, fault tolerance, high sensing
fidelity, low cost, and rapid deployment
characteristics ofsensor networks create new and
exciting application areas for remote sensing.
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So, what has come new this month ?
Sensor System Types Brilliant Rocks

• Largely unexplored
• Larger PC/PDA class devices
• Multimedia sensors
• Sensors shared by many applications
• Parking space finder
• Person locator
• Bus locator
• Directly connected to Internet

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Example Parking Space Finder

• A distributed database maintains
• Spot availability data
• Address of parking spot
• Meter description
• Historical availability data
• Query Where is the cheapest empty parking spot
  near Wean Hall?
• Returns list of spaces, details on their meters

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IrisNet Architecture
Internet
Organizing Agents
Sensing Agent
User
Sensing Agent
Sensing Agent

• Organizing Agents (OA)
• PC-class or server-class processor, GBs of
  storage, Linux

• Sensing Agents (SA)
• PDA/PC-class processor, MBsGBs storage, Linux

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Before going into irisnet, where to fit the web
services
What can be done ?

• A lot in agents but will be reinventing of
  wheels ..given work on mobile agents
• My work
• Sensor Service (SS) creation/composition
• Sensor wrapper WS
• Integration of Motes/ Brilliant rocks
• Service discovery ( Vs Resource discovery )
• ( I may probably end up doing first two !!! )

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A World of Smart Sensors

• Webcams other smart sensors are everywhere,
  collecting vast amounts of data
• But, no effective tools for querying this data
  and extracting useful information

• Opportunities for new sensor-based services
• Rich, high bit-rate data sources
• Rich expressive queries range queries,
  aggregate queries, historical queries
• Internet-scale view vast collection of widely
  distributed sensors as a single queriable unit

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Example Parking Space Finder

• A distributed database maintains
• Spot availability data
• Address of parking spot
• Meter description
• Historical availability data

• Query Where is the cheapest empty parking spot
  near Intel Research?
• Returns driving directions to the best spot

One of many possible sensor services
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IrisNet Internet-scale Resource-intensive Sensor
Network services
IrisNet
Other Sensor Projects
Webcams are typically attached to computers with
significant processing power memory
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Brilliant Rocks vs. Smart Dust

• Smart Dust
• mote hardware
• TinyOS, TinyDB, etc.
• campus-scale
• minimal sensor processing
• energy is a key concern
• scalar sensors
• narrowly focused services
• ad hoc wireless connectivity

• Brilliant Rocks
• PCs/PDAs
• Linux, Java, XML, C
• Internet-scale
• intensive sensor processing
• powered nodes
• multimedia sensors
• wide variety of services
• direct Internet connectivity

Complementary agendas
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• Goal Build a scalable infrastructure for
  deploying sensor-based Internet services (using
  brilliant rocks) with
• Efficient query processing
• Filtering rich data feeds
• Shared sensors
• Internet-scale
• Ease of service creation

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IrisNet

• Some Challenges
• richness of query language vs. system complexity
• query routing at Internet-scale
• service-specific code at sensors requires domain
  knowledge
• trust / isolation in sensor sharing
• scalability and peak load performance
• ease of service creation vs. heterogeneous
  services

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IrisNet Architecture
Internet
Organizing Agents
Sensing Agent
User
Sensing Agent

• Organizing Agents (OA)
• PC-class or server-class processor, GBs of
  storage, Linux

• Sensing Agents (SA)
• PDA/PC-class processor, MBsGBs storage, Linux

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Sensing Organizing Agents

• Sensing agents (SA)
• Collect process data from sensors
• Shared across services
• Execute senselet code uploaded by OAs
• Send extracted information back to the OAs
• Organizing agents (OA)
• Provide database query facilities
• Group of OAs dedicated to one service
• Index, archive, aggregate, mine cache data from
  SAs
• Provide mechanisms for discovering relevant
  sensors, dealing with transient agents and
  balancing load across agents

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OA Groups
Parking Space Finder Organizing Agents
Sensing Agent
Sensing Agent
University
Downtown
Museum
Internet
Sensing Agent
Sensing Agent
Amy-John
Kim-Steve
Tom-Zoe
Person Finder Organizing Agents
Sensing Agent
Sensing Agent
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SA Architecture
Sensor Feed
wrapper
wrapper
Shared Memory
Network
wrapper
SA Daemon
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OA - Architecture
Xindice
OA Daemon
Network
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IrisNet Key Features

• Rich query language with low-latency queries
• Flexible data partitioning
• Efficient protected sharing of sensor nodes
• Partial match caching
• Query-specified freshness tolerances
• Monitoring logging support
• Ease of sensor service deployment

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Deploying a Webcam Sensor Service

• Locate desired webcams (add more if needed)

• Create DAML Hierarchy DAML S (or just SOAP/
• WSDL based service )

3. Create wrapper code download to SAs

• Create web-based front end that fires off Xpath
  queries

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Wrappers web service

• Binary code fragments uploaded by OAs to SAs
• Perform intensive data filtering
• E.g., image processing
• Leverage available processing power and memory
• SAs reduce high sensor data rates (e.g. webcams)
  into low rates
• data reduction is through service-specific code

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Coming out of IRIS

• Creating a WSDL/ SOAP SS must be an easy work (
  as XML has strict hierarchy nature )
• If we have various such Sensor WS, we can use
  either
• .NET GXA architecture WS-RoutingWS-referral
• DAML-S composition work ( pi-calculus Frame
  theory Petri nets ) Tedious work
• Traditional Web flow work ( web process etc ..)
  but too old technique
• SO, GXA is the best option !!!
• Wrapper service to the Sensing agents
• See what GIS Consortium has done SensorML and
  hard code for our Sas.
• This work will be necessary only if there is
  interaction of data between motes/ sensor rich
  systems etc

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GXA

• GXA, Global XML Web Services Architecture
• GXA consists of several specifications
• DIME Specification Index Page
• WS-Attachments
• WS-Coordination
• WS-Inspection
• WS-Referral
• WS-Routing
• WS-Security
• WS-Transaction

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WS-Routing

• Stateless, SOAP-based protocol for routing SOAP
  messages.
• With WS-Routing, the entire message path for a
  SOAP message (as well as its return path) can be
  described directly in the SOAP envelope.
• Designed for
• One-way two-way messaging
• Peer-to-peer conversations
• Long running dialogs.

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WS-Routing

• Why?
• SOAP-based specifications are designed to be
  composed with each other to provide a rich
  messaging environment.
• WS-Routing encapsulates a message path within a
  SOAP message.

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WS-Routing

• What is missing from SOAP?
• SOAP cannot indicate a message path that
  organizes a collection of Web Services that act
  as intermediaries into a sequence.
• Example
• SOAP message M generated by A can indicate which
  part of M is intended for B, C, and D.
• As SOAP message CANNOT indicate that the
  intermediaries should be organized as follows

D
B
C
A
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WS-Referral

• Provides a way to configure how SOAP routers will
  build a message path
• It is a protocol for inserting, deleting, and
  querying routing entries in a SOAP router.
• SOAP router is a web service that
• implements WS-Routing,
• Implements WS-Referral specification.
• A SOAP router may use WS-Referral to
• Learn about firewalls and other intermediaries
• Implement load balancing, etc.

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WS-Referral

• Key specifications for, if, go
• These can loosely be described as a for if
  then go via
• For any SOAP actor name matching the set of SOAP
  actors listed in the for element
• If the set of conditions listed in the if element
  is met and hence the statement is satisfied
• Then go via one of the SOAP routers listed in the
  go element

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What is done ?

• Mark-up of Camera Sensor Service
• Mark-up of PLF is easy and done
• Have to do the major part
• WS-Routing extensions
• Wrapper/ Mediator system for WS

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Thanks