Global Sensor Networks
A Platform for the Internet of Things
Ali Salehi,
Prof. Karl Aberer
1
What are Sensor Networks ?
Sensors,
and Actuators,
Interconnected!
Sensors
Actuators
2
Properties of existing solutions
Time consuming
Hire
Expert(s)
Expensive
To Modify
People don't benefit from sensor networks.
3
Motivation,
?
?
4
Question : What is common ?
1. Stream of Data.
2. Structure can be defined.
3. Common Requirements.
Virtual Sensor
5
WHAT DOES ALL THIS MEAN
Internet of Things.
6
Solution,
A Software :
Hardware independent, any new hardware (sensors and
actuators) should be integratable.
Application independent.
Light & Scalable (internet scale ; peer to peer)
Modifications MUST be very cheap and simple.
Modifications MUST be applied while system is running.
Restarting the internet ?!!!
7
Design, Global Sensor Networks
Common data processing,
management and interfacing
requirements, off the shelf.
GSN = implementation of the
virtual sensor concept and the
all the listed requirements.
Multi layered architecture to be
deployable on resource
constrained devices.
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Simplicity, Simplicity, Simplicity (1)
Email to MMS
Service
(swisscom)
Application description
A ) Select Image from Camera
B ) Select Temperate from MoteA
Select Camera.Image
from A[window 1],B[window 10min]
where avg(temperature) >30
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Control Engineers
Automatic Control Laboratory ,ETHZ
Requirements: Simplicity, Unified Abstraction.
Light &
Temperature
GSN
Matlab Controller
Electric
blinds
10
Stream Services


Develop sensor network applications :
 Virtual sensors.
 Might produce a stream of data (service).
Buy a stream source :
 Hardware and/or Service (E.g., Lausanne
temperature ).
GSN
Stream
Sources
Virtual
Sensors
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Simplicity, Simplicity, Simplicity (2)
Self identifying devices (IEEE 1451).
TEDS and Virtual TEDS.
TEDS
+
Template
Virtual
Sensor
=
New
Virtual
Sensor
Zero-programming deployment.
12
High Level View of The GSN
* Uniform API for developing Sensor Network Applications.
* Declarative Requirement Management.
* Uniform API for exporting sensor data to the GSN.
* Various protocols (interfaces) for accessing data.
13
Resource Discovery
Addressing the virtual sensors :
Static (e.g., socket address).
Dynamic using a set of predicates :
Using a Directory Service:
<predicate key=“GPS.Latitude”>46.3423</predicate>
<predicate key=“Type”>temperature</predicate>
Distributed Directory Service (DDS)*:
Based on P-Grid infrastructure.
Each node acts as a peer in DDS.
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* Not implemented yet.
Resource Constrained Devices
Resources are allocated on demand.
Resource sharing as much as possible.
20 virtual sensors, 10% > CPU, 64MB RAM,
500 Mhz.
Requirements (e.g., Nokia 770),



32-bit processor.
64 MB Memory and/or Swap Option.
25 MB Storage.
15
Wrappers, as of Today
Bridge between the sensors/actuators and the GSN.
Wrappers
Actuators
TinyOS 1.x
SMS Service.
TinyOS 2.x
Email Service.
Wise Nodes
Pages Service.
TI RFID Readers (20cm)
Alien Tech. Readers (20m)
Fax Service.
Wired Cameras
EPuck Robots.
Networked Cameras
Speaker Output (AT&T)
Generic Bluetooth Protocol
IEEE 1451 Compatibility
Generic Serial
Generic UDP
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Outcome as of today.
Successful Open Source Project.
More than 20 sensors/actuators supported.
7 Releases of the engine (Stable).
30K visitors, 600 downloads.
Users Community
GNU GPL License
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WHAT DOES ALL THIS MEAN
GSN, Middleware for Internet of Things.
Q/A
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