PowerPoint Presentation

LiveFileA compact and interrogative system for

data collection

June 4th, 2007

International Workshop on Wireless Sensor Networks

NOTERE 2007

1LIMOS Laboratory UMR 6158 CNRS, Blaise Pascal University, France2Cemagref, UR TSCF/UMR TETIS, France3Harbin Institute of Technology, China

Gil De Sousa1, Pr Kun-Mean Hou1 ,Hai-Ying Zhou3 ,Christophe de Vaulx1 and Jean-Pierre Chanet2

Introduction

• Wireless Sensor Network (WSN)– Various applications

• Monitoring applications

– Resource awareness• Memory management

• LiveFile system– Interrogative file system

– LiveNode network• LiveNode wireless sensor• LIMOS operating system

International Workshop on Wireless Sensor Networks, NOTERE 2007 2

Plan

I. Motivations

II. LiveFile presentation and functionalities

III. LiveFile deployment


I. Motivations


Wireless Sensor Networks

• Examples of applications– Monitoring

• “smart care, smart home” applications

• Environmental monitoring

• Mobile tracking

– Fixed infrastructure substitution• Emergency rescue

• Conference organisation


Wireless sensors

• Small electronic devices– Equipped with different communication protocols

• WiFi (IEEE 802.11), Bluetooth and Zigbee (IEEE 802.15)

– Limited available resources• Energy, memory and processing

• Development of dedicated software– Operating system

• Examples of wireless sensors– Mica and TmoteSky motes– LiveNodes


Monitoring applications

International Workshop on Wireless Sensor Networks, NOTERE 2007

Observed environment

Data collection

Data transmission

Wireless sensor

Sink node

7

Monitoring applications

Compromise between transmission and storage

International Workshop on Wireless Sensor Networks, NOTERE 2007

Observed environment

Data collection

Data transmission

Wireless sensor

Sink node

7

Data storage

• Increase of the available memory– ATMEL AT91SAM7S256 microcontroller

• 64KB of SRAM• 256KB of internal Flash memory

• Flash memory management– Non volatile storage– Partitioned memory

• 1024 pages of 256 bytes

– Limited number of programming operations• 10,000 times per page

– Page programming time• 6ms


II. LiveFile presentation and functionalities


LiveFile design

• Existing micro-file systems– ELF

• Basic primitives for file operations

• Intelligent memory page use

– Capsule– MicroHash

• LIMOS Versatile Embedded File system– Integration into LIMOS operating system


LIMOS and LiveFile

HARDWARE

LIMOS Operating System

LiveFile (µFile System + µDBMS)

LiveNode


LiveFile functionalities

• Micro-file system– Memory management– Intelligent read and programming operations– Metadata concept

• Interrogative data system– Data queries

• Key features– Adaptive system– Resource aware– Component based concept


Adaptive system

• Adaptation to the collected data– Data format

• Size (type)

• Examples– Temperature and pressure measurements

• Customize page header– Main attributes

• Number of programming operations

• Storage type


Basic virtual flash memory structure

P1R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm

P2

P3

Pn-1

Pn


Virtual flash memory structure

HEADER DATA

FILE ... F1 F2

FILE ... F2 F3

... ... ... ...REC R(n-1)2 ... R(n-1)m

...

P1

P2

Pn-1

Pn


Customize page header

• Classical attributes– State “S”

• Idle/Busy

– Number of programming operations “N”– Record type “T”

• Record/File/Checkpoint

– Checksum “C”

S N T data C…


Resource aware

• Data manipulation– A maximum of 4 SRAM buffers needed

• 3 writing/programming buffers

– Trigger events for writing on Flash memory• A scheduled reboot

• A full writing SRAM buffer

• Writing Rotation Process (WRP) feature– Preservation of flash memory lifetime

• Limitation of the number of programming operations on each flash memory page


Programming operation


... (a)P1

P2

P3

Pn-1

Pn

R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm

... (b)

... (c)



... (a)

... (b)

... (c)

P1

P2

P3

Pn-1

Pn

R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm



... (a)... (a)

... (b)... (b)

... (c)... (c)

P1

P2

P3

Pn-1

Pn

R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm

LIMOS key features

1 event_code Event identifier

2 event_state Event state

3 event_thread_table A thread table pointer that points to the threads of this event

4 event_tuple Tuple identifier that points to the tuple associated with this event

5 event_tuple_msgnum Message number in the event tuple

6 event_priority Event priority level

E1

E2

Thread SchedulerE

ven

t M

ana

ger

Tn1 Tn2 Tn3 ... TnmnEn

T11 T1m1T12 T13 T14 …

T21 T22 ... T2m2

.

.

.


Component based concept

• Abstraction layer for memory use– Inter-Process Communication principle

• “tuple” notion from LINDA concept

• Primitives IN() and OUT()

Thread

Event

CPU

Peripheral

OUT

IN

Tuples space

Tuple(key)


Interrogative data system

• Concept– Key words and metadata concept

• Forecasted queries– Types of data collected

• Basic queries obtained by using modified primitive IN()

int In(char Key, unsigned char *MsgPtr, int MsgLen);


OUT() abstraction


P1

P2

P3

Pn-1

Pn

R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm

...

...

OUT(Flash,…)

IN() abstraction


P1

P2

P3

Pn-1

Pn

R11 R12 ... R1m

R21 R22 ... R2m

R31 R32 ... R3m

... ... ... ...

R(n-1)1 R(n-1)2 ... R(n-1)m

Rn1 Rn2 ... Rnm

...IN(Flash,…)

Metadata concept

• Illustration– “V1”

• Temperature “0”

• Pressure “1”

– “V2”• Comparison with a fixed threshold

– Above “0” / Below “1”


0 1

0 0

1 1

... ...

1 1

0 0

R11

R12

R13

Rn(m-1)

Rnm

V1 V2

III. LiveFile deployment


MobiPlus project

• Purpose– Improvement of the public transportation service– Provide a service depending on the person handicap

• Disabled, wheelchair and blind people

• MobiPlus deployment– Bus station system

• RFID detection and treatment feature

• RFID tag with person handicap

– Bus system• Inform driver

• Accessibility devices


Bus station organisation


Bus equipment

LiveNodeBus antenna

Vocal advertiser

Bus accessibility platform


Environmental projects

• Purpose– Environmental monitoring

• Hydrasol project– Soil moisture

– Fixed infrastructure substitution• Net-ADDED project

– Farm communication architecture


Environmental project


Sink node

Conclusion

• LiveFile– Interrogative micro-file system– Resource aware system

• A complete platform– LiveNode

• LIMOS operating system

• LiveFile system

– Adaptive system


Ongoing and future works

• Auto-configuration

• Ad Hoc routing protocols– Routing table management

• CIVIC protocol

• Evaluation– Comparison between TinyOS/TinyDB and LIMOS/LiveFile

on the same platform• LiveNode platform


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