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
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Plan
I. Motivations
II. LiveFile presentation and functionalities
III. LiveFile deployment
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I. Motivations
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Wireless Sensor Networks
• Examples of applications– Monitoring
• “smart care, smart home” applications
• Environmental monitoring
• Mobile tracking
– Fixed infrastructure substitution• Emergency rescue
• Conference organisation
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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
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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
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II. LiveFile presentation and functionalities
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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
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LIMOS and LiveFile
HARDWARE
LIMOS Operating System
LiveFile (µFile System + µDBMS)
LiveNode
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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
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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
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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
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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
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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…
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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
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Programming operation
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... (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)
Programming operation
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... (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
Programming operation
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... (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
Programming operation
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... (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
.
.
.
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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)
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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);
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OUT() abstraction
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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
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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”
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0 1
0 0
1 1
... ...
1 1
0 0
R11
R12
R13
Rn(m-1)
Rnm
V1 V2
III. LiveFile deployment
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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
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Bus station organisation
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Bus equipment
LiveNodeBus antenna
Vocal advertiser
Bus accessibility platform
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Environmental projects
• Purpose– Environmental monitoring
• Hydrasol project– Soil moisture
– Fixed infrastructure substitution• Net-ADDED project
– Farm communication architecture
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Environmental project
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Sink node
Environmental project
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Sink node
Conclusion
• LiveFile– Interrogative micro-file system– Resource aware system
• A complete platform– LiveNode
• LIMOS operating system
• LiveFile system
– Adaptive system
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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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