1. 16th FFV Workshop
MobileWebServices
in Health Care and Sensor Networks
FahadAijaz
Department of Communication Networks
RWTH Aachen University, Germany
FFV Workshop, 13.03.2009
Fahad Aijaz, ComNets, RWTH Aachen University

2. Outline
• Wireless Sensor Networks
– A General Introduction
– Problem Statement
– Scientific Framework
• Service-Oriented Wireless Sensor Networks
– Use Cases and Requirements
• Mobile Web Services
– Types and Interactions
• Advanced Mobile Web Service Architecture
– Overview
– Black-box Architecture
– Service Control and Monitoring
• Service-Oriented WSN Environments
– A Collector Node Scenario
– Healthcare Scenario and Requirements – MEDICARE
– Measurement of Power Consumption
• Future Mobile Web Services Research at ComNets
Fahad Aijaz, ComNets, RWTH Aachen University 2

3. Wireless Sensor Networks (WSN)
(A General Introduction)
• A WSN is a wireless network consists of spatially distributed
devices using sensors.
• Sensors monitor the physical or environmental conditions at
different locations, e.g.
– Temperature
– Sound
– Vibration
– Pressure
– Motion etc.
• Such networks are the key for gathering information
in smart environments.
• Some application areas are;
– Monitoring and Control Systems
– Health care
– Traffic control
– Security
– Home automation etc.
Image source: http://www.purelink.ca/images/sensor_network_big.gif
Fahad Aijaz, ComNets, RWTH Aachen University 3

4. Wireless Sensor Networks (WSN)
(Problem Statement)
• Typically, a WSN performs distributed
network computations to meet its specific Sensor Node
needs.
• Data received by sensors is processed with Applications Applications
limited processing capabilities of
a sensor node.
• Complex network computations demand
high processing power within a sensor node.
Applications
Applications
• This results in high power consumption
and affects network performance.
Sense/Store Data
:
Issues: Low processing power, Battery Limited Processing
consumption, Network performance :
Transmit
Fahad Aijaz, ComNets, RWTH Aachen University 4

5. Wireless Sensor Networks (WSN)
(Scientific Framework)
 Collector nodes introduced in [1] are better Sensor Node
equipped in terms of processing power and battery
consumption than ordinary sensors.
Collector Node
 High-valued distributed in-network computations
can be achieved by collector nodes‘ collaboration.
 Collector nodes represent local neighborhood of
sensors to higher hierarchy of WSN.
 Collector nodes equipped with Mobile Web Services to
perform local computations.
 Cooperation among the collector nodes would initiate
higher-valued Mobile Web Services for complex
distributed in-network computations.
Receive Sensor Data
 Sense/Store Data
Study new fields in the area of Mobile Web :
:
Services to identify realistic business and Perform Computations
Limited Processing Collaboration
application scenarios. :
:
Represents WSN
Transmit
Scientific Challenges
 Network computations in wireless networks.
[1] Giridhar, A. Kumar, P.R., Toward a theory
 Organization of cooperative collector nodes owning of in-network computation in wireless sensor
Mobile Web Services. networks, Communications Magazine, IEEE,
 Gain a high-valued network based on Mobile Web Volume 44, Issue 4, p. 98- 107, ISSN:
Services. 0163-6804, 2006
Fahad Aijaz, ComNets, RWTH Aachen University 5

6. Service-Oriented Wireless Sensor Networks
(Use Cases and Requirements)
Long-Lived Service
Processes Management
Wireless Service
Mobile
Web Services
Sensor Oriented
?
Framework
Networks Computing Interaction Event
Patterns Notifications
Service Oriented Wireless Sensor Networks Short-ranged
Data Comm.
Representation
.
Req.
Req
q.
.
eq
Re
R
Long-ranged
Comm.
Healthcare | Traffic control | Security | Home automation …
Domain Specific Applications
Enough?
Mobile Web Services Framework
Fahad Aijaz, ComNets, RWTH Aachen University 6

7. Mobile Web Services
(Types and Interactions)
WS Provider
WS Consumer
Execution Model Consume
Mobile Mobile
Web Server Web Server
(SOAP)
entails
Mobile Mobile
Web Services Web Services
Synchronous Asynchronous
(Short-lived) (Long-lived)
Publish
Mobile Synchronous Search
Interaction (MSI) (UDDI)
(WSDL)
Mobile Asynchronous Web Service
Interaction (MAI) Broker
1. Request-response
2. Solicit-response
derives derives 3. One-way
4. Notification
P2P Mobile Web Services
WSDL Operations
(Transmission Primitives)
Fahad Aijaz, ComNets, RWTH Aachen University 7

8. Mobile Web Services
(Mobile Synchronous Interaction)
Request – Response Operation Services are
Immediate service
Pros: simple, quick, reliable, widely applied … instantaneous
invocation
(short-lived)
Cons: change management (undo, cancel…), long running tasks,
human involvement, blocked client …
MOBILE TERMINAL 2 (MT
MOBILE TERMINAL 1 (MT 1)
2)
Mobile Mobile
MobWS MobWS
Application Application
Proxy Proxy
(M1) (M2)
MOBILE SYNCHRONOUS
REQUEST
MOBILE SYNCHRONOUS
WEB SERVICES
INVOKED
WEB SERVICES
M2-1
M1-1
SHORT-LIVED
BLOCKED
INTERNET
/NETWOR M2-2
M1-2
K
M2-n
M1-n
RESPONSE
DETELP M C
O
Request-response are transmitted on
Requester remains in same network infrastructure
a blocked state (e.g. UMTS, GPRS, WLAN …)
Fahad Aijaz, ComNets, RWTH Aachen University 8

9. Mobile Web Services
(Mobile Asynchronous Interaction)
Request – Response AND Solicit – Response Operation Services are not
Pros: two-way control, long processes, unblocked client, back-end operations, human instantaneous
involvement, change management, reliable … (long-lived)
Temporal service
Cons: complex, blocked until ACKed, correlation, larger payloads … invocation possible
MOBILE TERMINAL 1 (MT 1) MOBILE TERMINAL 2 (MT
“Push” Model (Callback)
2)
“Pull” Model (Polling) Mobile Mobile
Supports MobWS INTERNET / NotificationMobWS
One-way AND NETWORK Operation!
Application Application
Proxy Proxy
INFRASTRUCTURES
(M1) (M2)
MOBILE ASYNCHRONOUS
MOBILE ASYNCHRONOUS
WEB SERVICES
WEB SERVICES
INVOKED
REQUEST
UNRELIABLE! M2-1
BLOCKED
M1-1
(no ACKs, no blocking)
LONG-LIVED
M2-2
M1-2
RESPONSE
SOLICIT
BLOCKED
M2-n
M1-n
DETELP M C
O
RESPONSE
Support for multiple network infrastructures for service invocation
Unblocked client and response (e.g. request UMTS, response WLAN)
Fahad Aijaz, ComNets, RWTH Aachen University 9

10. Advanced Mobile Web Services Architecture
(General Overview)
Asynchronous
Communication Architecture
Extended Mobile Web Services Framework
Creation, Control
& Monitoring
Factory
Context
Application Creates
Data
Instance
Observer
Asynchronous Service Middleware
Asynchronous Service Asynchronous
Web Service
Access Protocol Instance Notification
Services
Control
(OASIS Standard) and Polling Callback
Interaction Mechanisms
Monitoring
Observer
Factory
Service
Service
Consumer
Consumer
(WS-C)
(WS-C)
SOAP
ASAP
ASAP
WS-Eventing SOAP Server
Service
Service
WS-Addressing Provider
Provider
(WS-P)
(WS-P)
Data Representation
WS-C repeatedly WS-C registers with
requests WS-P the WS-P for status
HTTP
UDP
TCP SR-UDP
Asynchronous until response notifications
Data Representation
Mobile Web Services is obtained
Transport Layer
Component
Middleware
Context Data
Context Data
SOAP Message
Java Object
IP Layer
De-serialization
Client
Serialization
Service
Result Data
Result Data
SOAP Message
Java Object
Fahad Aijaz, ComNets, RWTH Aachen University 10

11. Advanced Mobile Web Services Architecture
(Black-box Architecture)
Asynchronous Mobile Web Services Framework
Communication Architecture SOAP Server
Asynchronous Request Management
Invocation,
Mobile Web Service
Creation, Control
Listener
Control and Request
ASAP
Factory 1
& Monitoring
Monitoring Handler
Handler
Factory
Request
Creates
Instance
Instance
Observer
Observer
Listener
Response
Deployment
Asynchronous
N
Handler
Interface
Web Service
Polling Callback
Notification
Interaction Mechanisms
Service
Service
Mobile Web Service
Consumer
Consumer
(WS-C)
Response
(WS-C)
Synchronous and
Notify
Asynchronous
Mobile Web Services
Service
Service
Provider
Provider
 Request Handler processes all incoming requests, but handles only
(WS-P)
(WS-P)
synchronous requests passing the asynchronous requests to ASAP Handler.
WS-C repeatedly WS-C registers with
requests WS-P the WS-P for status
until response notifications
 ASAP Handler handles asynchronous requests.
is obtained
 Asynchronous framework supports both Polling and Callback interaction
techniques.
 Synchronous and Asynchronous Services are deployed in a similar way by
the same Deployment Interface.
Fahad Aijaz, ComNets, RWTH Aachen University 11

12. Service-Oriented WSN Environments (1/2)
(A Collector Node Scenario)
Collector Node (B) 
 Collector Node (A) Sensors
Nodes
Shared
Service
Service Discovery
Information Sharing Computing
(Synchronous MWS)
(Asynchronous MWS Monitoring)
Service Collaboration
(Asynchronous MWS Control) Thresholds
A1
Asynchronous
A2
A4
Services
A3
(Long-Lived)
Service Creation Service Creation
S1
Data Representation
Synchronous
S2
S4
Services
S3
(Short-Lived)
Network Server Events / Analyze
Fahad Aijaz, ComNets, RWTH Aachen University 12

13. Service-Oriented WSN Environments (2/2)
(Healthcare Scenario and Requirements - MEDICARE)
Sun Small Programmable Object Technology (SunSPOT)
Synchronous
Services
Activity / Mode
Sun SPOT
Performance
Node
Specifications:
Configuration Equipment
Light
180 MHz 32 bit ARM920T core
Valves and tubes
Oxygen amount RAM/4M Flash
512K
2.4 GHz radio with integrated antenna
..... Heater
Monitor Ventilator
3.7V rechargeable 720 mAh lithium-ion battery
IEEE 802.15.4 based radio communication
Public Key Cryptography (Elliptical Curve Cryptography (ECC))
Door
Synchronous
Services
Sensor Board:
2G/6G 3-axis accelerometer
Temperature sensor Environment
Asynchronous sensor
Light
Services tri-color LEDs
8 Room Temperature
2 momentary switches Light Conditions
Patient
Door
Extendable with general purpose I/O and high current output pins! Presence
Noise
.....
Blood pressure
Asynchronous
Operating Modes: Heartbeat Services
Breathing
Run mode: 70ma to 120ma (10.28 to 6 hrs)
Health
Creation
Service Discovery Services’ Classification
Composition Doctor’s PC
Idle ModeMovement
(Shallow sleep): 44ma (16.36 hrs)
Pulse
Deep Sleep: 32uA (22500 hrs/ 937.5 days/2.6 years)
Sun SPOT
(Asynchronous Operation)
(Synchronous Operation)
..... (Base Station)
Fahad Aijaz, ComNets, RWTH Aachen University 13

14. Power Consumption of SunSPOT Nodes
Next Generation of Sun SPOTs might
turn out to be
SOLAR POWERED!
Source:
Sun Technical Report - TR-2009-178 (February 2009)
“Experiments with a Solar-powered Sun SPOT”
http:/ research.sun.com/
/ techrep/2009/abstract-178.html
Switched off LEDs  20 % optimized battery consumption
Further optimization is possible! (modes, payload, threads…)
Fahad Aijaz, ComNets, RWTH Aachen University 14

15. Future Mobile Web Services Research at ComNets
• P2P Service Level Agreements
– Negotiations
– Active and pending agreements
– Per service agreement templates
– Service Guarantees
– REST and SOA compatible
• Service-oriented WSN Integration with IP Multimedia
Subsystem (IMS)
– IMS Services API (JSR 281) for Java ME
– Extended IMS enabled health care prototype
• Server-side IMS application
• IMS enabled Java ME application
– High-valued context-sensitive IMS use case
Fahad Aijaz, ComNets, RWTH Aachen University 15

16. Thank you for your attention !
5
Questions are welcome!
Fahad Aijaz, ComNets, RWTH Aachen University 16