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BSN and Its ApplicationsThe slides were provided by Prof. Benny Lo and Prof. Guang-Zhong Yang
from Imperial College London
Administration Issues
Project Proposal submission (email to wanghbell@gmail.com or hwang1@umassd.edu) by March 12, 2015
See project proposal guideline on class website.
No lecture on March 12 due to my trip to NSFPlease work on the project with your group members either in the lab
or classroom during the class time on March 12 Have a nice spring break
The Hamlyn CentreThe Institute of Global Health Innovation
use body as the media and a source of inspiration, energy to provide long-term, continuous sensing, monitoring and intervention
BSN
The Hamlyn CentreThe Institute of Global Health Innovation
Quantitative assessment of patients
www.policymed.comBupa UK www.pupin.rs
The Hamlyn CentreThe Institute of Global Health Innovation
WSN vs BSNChallenges WSN BSN
Scale As large as the environment being monitored (metres/kilometres) As large as human body parts (millimetres/centimetres)
Node Number Greater number of nodes required for accurate, wide area coverage Fewer, more accurate sensors nodes required (limited by space)
Node Function Multiple sensors, each perform dedicated tasks Single sensors, each perform multiple tasks
Node Accuracy Large node number compensates for accuracy and allows result validation Limited node number with each required to be robust and accurate
Node Size Small size preferable but not a major limitation in many cases Pervasive monitoring and need for miniaturisation
Dynamics Exposed to extremes in weather, noise, and asynchrony Exposed to more predictable environment but motion artefacts is a challenge
Event Detection Early adverse event detection desirable; failure often reversible Early adverse events detection vital; human tissue failure irreversible
Variability Much more likely to have a fixed or static structure Biological variation and complexity means a more variable structure
Data Protection Lower level wireless data transfer security required High level wireless data transfer security required to protect patient information
Power Supply Accessible and likely to be changed more easily and frequently Inaccessible and difficult to replace in implantable setting
Power Demand Likely to be greater as power is more easily supplied Likely to be lower as energy is more difficult to supply
Energy Scavenging Solar, and wind power are most likely candidates Motion (vibration) and thermal (body heat) most likely candidates
Access Sensors more easily replaceable or even disposable Implantable sensor replacement difficult and requires biodegradability
Biocompatibility Not a consideration in most applications A must for implantable and some external sensors. Likely to increase cost
Context Awareness Not so important with static sensors where environments are well defined Very important because body physiology is very sensitive to context change
Wireless Technology Bluetooth, Zigbee, GPRS, and wireless LAN, and RF already offer solutions Low power wireless required, with signal detection more challenging
Data TransferLoss of data during wireless transfer is likely to be compensated by number of sensors
usedLoss of data more significant, and may require additional measures to ensure QoS and
real-time data interrogation capabilities
The Hamlyn CentreThe Institute of Global Health Innovation
Biosensors - Introduction Analytical devices which use biological interactions to provide either
qualitative or quantitative measurements
Bio-receptor is a chemical/biological molecular recognition element (ex. antibody, enzymes, DNA, cells, tissue, or whole organ)
Transducer converts the recognition event into a electrical signal (ex. electrodes, pH electrode, thermistor, photon counter, piezoelectric device)
Transducer signalBio-receptor
Biosensor
http://www.wolfminimaze.com/tab02.htm
The Hamlyn CentreThe Institute of Global Health Innovation
Low power processing
Efficient hardware Integration and isolation (DMA, USART, etc) Selectable Power States (Off/Sleep/Standby) Operate at low voltage and low current
Run to cut-off voltage of power source
Efficient Software Fine grained control of hardware Utilise wireless broadcast medium Aggregate
The Hamlyn CentreThe Institute of Global Health Innovation
Low power processing
Periodic Data collection Network Maintenance Majority of operation
Trigger Events Detection/Notification Infrequently occurs
Long life time Months to years without
charging Power management is
the keysleep
wak
eup
processingdata acquisitioncommunication
Po
wer
Time
The Hamlyn CentreThe Institute of Global Health Innovation
Embedded Operating System - TinyOS Micro thread, event triggered operating system
framework
Structures run-time software into components and provides fine-grained allocation of processing resources across multiple components
Shield the application level processing from the underlying concurrent scheduling, yet exposes low-level system components to meet their real time requirements
NesC, a new programming language with C-like syntax, is used
Multi-hop routing and encryption is incorporated in the communication architecture of the TinyOS
TinyOS component
Communication architecture
The Hamlyn CentreThe Institute of Global Health Innovation
Regulations/Standards 402-405Mhz for medical implant communication
service (MICS) 608-614MHz, 1395-1400MHz and 1427-1432MHz
for medical telemetry IEEE 802.15.6 – Body Area Network (BAN) Bluetooth Smart IEEE 1073 – Standard for medical device
communication HL7 - Standards for the exchange, management
and integration of data that support clinical patient care and the management, delivery and evaluation of healthcare services.
The Hamlyn CentreThe Institute of Global Health Innovation
ISM band Industrial, scientific and medical (ISM) radio bands
Frequency range Bandwidth Center Frequency Availability
6.765 MHz 6.795 MHz 30 kHz 6.780MHz Subject to local acceptance
13.533 MHz 13.567MHz 14 kHz 13.560MHz Worldwide
26.957 MHz 27.283 MHz 326 kHz 27.120 MHz Worldwide
40.660 MHz 40.700MHz 40 kHz 40.680 MHz Worldwide
433.050 MHz 434.790 MHz 1.74 MHz 433.920 MHz Region 1 (Europe, Middle East and Africa)
902.000 MHz 928.000 MHz 26 MHz 915.000 MHz Region 2 (America)
2.400 GHz 2.500 GHz 100 MHz 2.450 GHz Worldwide
5.725 GHz 5.875 GHz 150 MHz 5.800 GHz Worldwide
24.000 GHz 24.250 GHz 250 MHz 24.125 GHz Worldwide
61.000 GHz 61.500 GHz 500 MHz 61.250 GHz Subject to local acceptance
122.000 GHz 123.000 GHz 1 GHz 122.500 GHz Subject to local acceptance
244.000 GHz 246.000 GHz 2 GHz 245.000 GHz Subject to local acceptance
Source: wikipedia
The Hamlyn CentreThe Institute of Global Health Innovation
Wireless standards operating in the ISM band
Data rates (bps)
Range
Proprietary low-power radio
• Gaming consoles• PC Peripherals• Audio• Meter Reading• Building automation• Automotive
1000m
100m
10m
1m
Zigbee (802.15.4)
1k 10k 100k 1M 10M 100M
• Building automation• Smart home• Manufacturing• Parcel Tracking• Environmental monitoring• Smart Meter• Health monitoring
Bluetooth
• Headsets• PC Peripherals• Phone
Wifi 802.11
• PC Networking• Home networking• Video distribution
UWB• Wireless
USB• Video/
audio links
http://www.eetimes.com/document.asp?doc_id=1276399
The Hamlyn CentreThe Institute of Global Health Innovation
ZigBee Topology Models
ZigBee coordinator
ZigBee Routers
ZigBee End Devices
Star
Mesh
Cluster Tree
The Hamlyn CentreThe Institute of Global Health Innovation
Bluetooth Smart
Zigbee Bluetooth Bluetooth Smart
Range 10-100 m 100m 50m
Topology Ad-hoc, peer to peer, star or mesh
Scatternet Star-bus
Operating Frequency 868 MHz, 900-928 MHz, 2.4 GHz
2.4 GHz 2.4 GHz
Peak Power consumption <25mA <30mA <15mA
Security 128 AES 56/128 bit 128 AES
Data rate 250 kbit/s 1-3MBit/s 1 Mbit/s
Network joining time 30ms 100ms 6ms
The Hamlyn CentreThe Institute of Global Health Innovation
Power Scavenging Photovoltaics (Solar cells)
15-20% efficiency (single crystal silicon solar cell) 15mW/cm2 (midday outdoor) to 10µW/cm2 (indoors)
Temperature Gradients 1.6% efficiency (at 5oC above room temperature) 40 µW/cm2 (5oC differential, 0.5cm2, and 1V output)
Human Power Human body burns 10.5MJ/day (average power dissipation of 121W) 330 µW/cm2 (piezoelectric shoe)
Wind/Air Flow 20-40% efficiency (windmills, with wind velocity 18mph)
Vibrations Electromagnetic, electrostatic, and piezoelectric devices 200 µW (1cm3 power converter with vibration of 2.25 m/s2 at 120Hz)
Nuclear microbatteries With 10 milligrams of polonium-210, it can produce 50mW for more than 4 months It can safely be contained by simple plastic package, as Nickel-63 or tritium can
penetrate no more than 25 mm
Panasonic BP-243318
Applied Digital Solutions – thermoelectric generator
MIT Media Lab
MIT – MEMS piezoelectric generator
Cornell University - Nuclear micro-generator (with a processor and a photo sensor)
The Hamlyn CentreThe Institute of Global Health Innovation
Power generation and radio transmission optimisation
Mitcheson, Yates, Yeatman, Green and Holmes, BSN 2005
The Hamlyn CentreThe Institute of Global Health Innovation
Context awareness Reliable detection of patient activity is important to the capture of
clinically relevant episodes
However, to determine human activities normally requires the use of a large number of sensors around the body, which is not practical
Identifying sensors that have direct implication to the decision process is essential for BSN
Reduction of sensors/features implies less data transmission and more efficient data mining
The Hamlyn CentreThe Institute of Global Health Innovation
Sensor fusion
EventsEpisodes Diagnosis
Pre-processing
Feature Level Fusion
Domain-specific & High-level Knowledge
Source Separation
Sensor Calibration/Synchronisation
Data Normalisation
Decision Level Fusion
Distributed Inference
Centralized Inference
…
SensorC
SensorB
SensorA
Feature Selection
Dimensionality Reduction
Recognition
Abstracted Data
Pre-processed Signals
OR
Feature Detection
Surapa Thiemjarus
The Hamlyn CentreThe Institute of Global Health Innovation
Network Security
SNEP (Secure Network Encryption Protocol) Uses RC5 Block cipher to encrypt unicast message A shared counter is used to encrypt the data with the block cipher Each sensor keeps a monotonically increasing counter to minimise the
overhead
Key
Counter i
Sensor A
Key
Counter i
Sensor BXORXOR
Plaintext Ciphertext….gfedcba
….x£7s5:’
Plaintext….gfedcba
Cipher Cipher
The Hamlyn CentreThe Institute of Global Health Innovation
Applications
http://www.cn-c114.net/578/a550320.html
http://wsnblog.com/2012/05/28/how-sensors-can-lead-us-to-better-self-knowledge/human-body-sensors/
Loughbough
CyberShoe
SensembleCUHK Cuff-less BP
Sibrecht Bouwstra, Wei Chen, Loe Feijs, Sidarto Bambang Oetomo, “Smart Jacket Design for Neonatal Monitoring with Wearable Sensors”, BSN2009
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