RETIS Lab

Real-Time Systems Laboratory

CPU-intensive applications in WSNs

Mangesh Chitnis and Paolo Pagano

Motivations • From the referee report of our paper accepted by WPDRTS07. Only one good recommendation: “They indicate that future work will focus on more complex routing structures; however, they are more likely to have impact if they focus on the following points in addition to or instead: – Simulations of actual WSN protocols that are CPU intensive. Most WSN protocols do very limited processing and are characterized mostly by communication issues. Experiments with a CPU-intensive protocol would be interesting.

– Implementing non-fcfs schedules in a mote, perhaps by modifying tiny-os to allow task preemption. An actual demonstration, showing they relative benefits of better scheduling, would be especially convincing.” June 20th Paolo Pagano (ReTiS Lab) 2

MultiMedia application examples

• Computer Aided Vision • Tracking and Surveillance • Object detection • Vehicle traffic avoidance • Industrial machine verification

June 20th Paolo Pagano (ReTiS Lab) 3

Used platforms • Cyclops (Mica2 and Mica-Z connected to low resolution camera), 8 bits ISA http://www.cyclopscamera.org/ • Stargate (XBow board, Intel xScale processor), 32 bits http://www.xbow.com/Products/Product_pdf_files/Wireless_pdf/6020-0049-01_B_STARGATE.pdf

June 20th Paolo Pagano (ReTiS Lab) 4

Domain Depiction

• MultiMedia applications offer two different families of problems:

– Computational Intensive Algorithms • Distributed Encoding & Decoding • Compression – Communication: • High Data Traffic with real time constraints.

• MAC and Network protocols for Multimedia in WSNs (e.g. 802.15.3, HR-WPAN) June 20th Paolo Pagano (ReTiS Lab) 5

Application Modeling and Schedulability • H/W – S/W co-design problem.

– Choice of Network Architecture, Node Architecture, Camera Sensors, etc – Mapping functionalities into tasks; – Scheduling the tasks on nodes for in-network processing, minimum schedule length and minimum energy consumption with reduced resource set.

• Big expertise offered by the lab: – Bartolini et al., 2005 (architectural modeling) – Pellizzoni and Lipari, 2004 and 2005 (transactions) – Recent works by Bertogna and Cirinei (multiprocessor scheduling) June 20th Paolo Pagano (ReTiS Lab) 6

Computer Vision in Multimedia WSN

• Distributed Image Processing:

– Image Enhancing, Enlarging, MultiViews. – Data Alignment and Image Registration.

• Different viewpoints, time & space • MWs developed for Querying and Processing. e.g.: IrisNet, DeepVision.

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Our proposal

• We tackle to Computational and Networking problems related to Computer Aided vision:

– Definition of RT-constraints; – Energy aware Modeling and Scheduling issues vs reduction of resource set;

• Using the rapid prototyping suite:

– Implementation on dsPic, AVR?

– Modeling the application in RTNS?

• RTSim support for transactions; – What time synchronization?

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What can we do in such a field? (1/4) as of January 15th • Simulation: – provide a complete 802.15.4-based simulation of a distributed system , specifically a layer for RT data-services; What do we miss?

– Correct processing of IRs and routing messages ; – RTSim support for transactions; – Protocols for sharing global schedule; – Time synchronization protocol; (if needed) – An advanced study of 802.15.4 libraries (namely clustering, routing, etc).

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What can we do in such a field? (2/4) as of January 15th • Programming the Real Hardware: – provide a complete 802.15.4-based RT distributed system localization case study and apply for RTAS08  . , specifically a MW for data service. Even we can do better the • • Completion of Network layer in EE (write and read 802.15.4 datagrams); The Atmel development kit Antonio ordered 3 months ago.

June 20th What do we miss?

Application

Network Stack

Kernel Layer Hardware Abstraction Layer CPU MCU Layer Board Layer

Now let’s go to the to-do list… Anna Fabio HIGH • Sensor reading in TinyOS; • Client/Server communication w/ TinyOS; Tullio Gianluca Tommaso Nino • RBS(*) implementation in TinyOS; • Transaction in RTSim; • Delay correction for IRs in Ns-2; HIGH Luca • Gateways and routing paths in Ns-2 ; • Sensor reading in ERIKA; • Network primitives in ERIKA; • Energy management for the motes; • NesC-like programming language for ERIKA.

(*) Basics of Time Synchronization are in ReTiS PLONE MEDIUM LOW Enrico Antonio Peppe Paolo Mangesh

High level hints? HIGH HIGH • CAP or CFP?

• Emulators for WSNs • Future meetings must address very specific and point-like issues instead of large survey as this one  • …………….

• …………….

MEDIUM LOW Peppe Giorgio

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