bsn and its applications the slides were provided by prof. benny lo and prof. guang-zhong yang from...

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 [email protected] or [email protected]) 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

mailto:[email protected]

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


Quantitative assessment of patients

www.policymed.comBupa UK www.pupin.rs


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


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


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


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


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


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.


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



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


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

http://www.eetimes.com/document.asp?doc_id=1276399


ZigBee Topology Models

ZigBee coordinator

ZigBee Routers

ZigBee End Devices

Star

Mesh

Cluster Tree


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


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)


Power generation and radio transmission optimisation

Mitcheson, Yates, Yeatman, Green and Holmes, BSN 2005


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


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


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


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

http://www.cn-c114.net/578/a550320.html



bsn and its applications the slides were provided by prof. benny lo and prof. guang-zhong yang from...

Documents

wireless transfer

solutionslow power wireless

static sensors

accurate sensors nodes

wireless lan

external sensors

hamlyn centre

wind power