Video of the Day. Ø LA Express Park Explained!

Transcription

1 Video of the Day LA Express Park Explained! 1

2 Proposal One proposal/team, 1 page! Team members! Concise description of project! Responsibilities of each member! Specific equipment needed! Written proposal due: 9/20 th, 11:59pm! to Mo! 2

3 Proposal Presentation 8 min per group! Including 3 min for questions! Your elevator pitch!! Mo your slides by 11am on 9/20 th! All use Mo s laptop à reduce context switches! 3

4 Agilla: Mobile Agent Middleware for Wireless Sensor Networks Chenyang Lu! Computer Science and Engineering!

5 Motivation Adaptive applications in wireless sensor networks! Adapt to changes in! the environment! the network! user requirements! 5

6 Example: Forrest Three applications: 1) Environmental Monitoring, 2) Fire Detection, 3) Fire Tracking! 6

7 Example: Forrest with Agilla Sensor network as a shared computing resource! Flexible application deployment! Env. monitoring agent Fire detection agent Fire tracking agent 7

8 Example: Cargo Tracking Thousands of containers leave/join network per day! Software need to be changed on the fly due to! Departure and arrival of containers! Container s country and company! Change in security levels and policies! Change in tracking technologies! Agilla: support adaptive applications in wireless sensor networks! 8

9 Agilla s System Architecture (1,1) (2,1) Agents Agents migrate Neighbor List Tuplespace remote access Tuplespace Neighbor List Middleware Services Agilla Middleware TinyOS Middleware Services Agilla Middleware TinyOS 9

10 Agilla s Computational Model PC Stack Condition Codes Heap Code Clone or Migrate Two variants of each: 1) Strong (code + state) 2) Weak (code only) 10

11 Mobile Agent Model Mobile agent: unit of execution that can move across hosts! Multiple mobile agents may share a host! Spatiotemporal decoupling => need shared data space with uniform interfaces! 11

12 Tuple Space-Based Coordination Content-addressable shared memory! Tuple A set of data fields! Template A pattern that matches particular tuples! Provides spatiotemporal decoupling in unreliable networks! rout in out in Tuplespace Tuplespace 12

13 Tuple Space Model Tuple: collection of data! <15, str, false>! Tuple space: shared data space containing tuples! Template: patterns which match tuples! <15, *, false> matches <15, str, false>! Common tuple space operations:! out(t): add tuple t to tuple space! rd(t): copy tuple matching template T from tuple space! in(t): remove tuple matching template T from tuple space! regrxn(t, c): execute code segment C when tuple matching template T is placed in tuple space! 13

14 Agilla Tuple Space API Remotely accessible localized tuple spaces! Stores context information! Facilitates inter-agent communication! out Tuplespace in out:!!insert! in:!!!remove! rd:!!!read! inp:!!probing remove! rdp:!!probing read! regrxn:! deregrxn: Local!register reaction!!deregister reaction! Remote rout:!insert! rinp:!probing remove! rrdp:!probing read! rrdpg:!probing group read (1-hop)! 14

15 Location-Base Addressing Nodes are addressed by location! (3,1) (3,2) (3,3) clone to (3,1) (2,2) clone to (3,3) (1,1) Fire Detection Agent (1,3) 15

16 Implementation on TinyOS Agilla is available for Mica2 and MicaZ motes! 4 agents/node! Agent Injector! Written in Java! Remote Injection via RMI! Key Challenges! Network bandwidth! Compact instructions! Memory! ROM: 54.7KB of 128KB! RAM: 3.5KB of 4KB! Message loss! Agent-level ARQ! 16

17 Experimental Set-up Ø 6x9 Mica2 Mote Testbed! Ø Multi-hop Grid! Ø One base station! 17

18 Performance Evaluation: migration vs. remote tuple space access Migration instructions are more reliable because of hop-by-hop acknowledgements but remote tuplespace operations have less overhead 18

19 Agilla Instruction Execution Times Local Operations Remote Operations 19

20 Experiences Fire Detection & Tracking! Presented at IPSN 2005! Intruder Detection and Tracking! Agents guard network perimeter and follow intruders! Periodically report intruder location to base station! Cargo & Inventory Management! In collaboration with Boeing! Mobile agents load manifests from RFID, find items, detect security breaches, and send alert to Internet gateways.! Demo at SenSys 2005! 20

21 Fire Tracking Video 21 Video available at:

22 Related Work Distributing inanimate code modules! XNP [xbow 03], Deluge [sensys 04], MNP [icdcs 05], SOS [mobisys 05]! Maté/Bombilla [asplos 02]! Mobile Agent-Like Middleware! Sensorware [mobisys 03]! Weak migration only! Smart Messages [Kang 04]! No remote interactions! Single thread per node! 22

23 Agilla Summary Mobile agent middleware simplifies application deployment & increases network flexibility! Agilla middleware services! Agent mobility! Tuple space-based coordination! Location-centric addressing! Context discovery! Empirical results demonstrate Agilla is reliable and efficient! 23

24 References C.-L. Fok, G.-C. Roman and C. Lu, Agilla: A Mobile Agent Middleware for Self-Adaptive Wireless Sensor Networks, ACM Transactions on Autonomous and Adaptive Systems, Special Issue on Self-Adaptive and Self-Organising Wireless Networking Systems, 4(3), Article 16, July Agilla: Source Code Documentation Tutorials Experience Reports 24

25 Agimone: Middleware Integration of Sensor and IP Networks!!! Chenyang Lu! Computer Science and Engineering!

26 Motivating Application: Cargo Tracking Ship Sensor Network Sensor Network IP Network Sensor Network Shipping Yard Customer, Shipper, DHS, CBP Train Sensor Network Truck 26

27 Problem Statement Weak radio => low radio range => isolated networks => reduced utility! Communication restrictions can be eased by connecting WSNs using a common IP network! Custom application-specific software is written to connect sensor and IP networks! Sensor and IP networks have vastly different characteristics and capabilities! Not reusable, error prone, inflexible! 27

28 Background: Two Distinct Middlewares Node (1,1) Node (2,1) Mobile Host 1 Mobile Host 2 Agents Neighbors Tuple Space Agilla Middleware migrate remote access Agents Tuple Space Neighbors Agilla Middleware Agents AQL AQL AQL TS TS TS Limone Server AQL TS migrate remote access Agents AQL AQL AQL TS TS TS Limone Server AQL TS TinyOS MICA2 Mote TinyOS MICA2 Mote Java VM Java VM Agilla: Sensor Network Middleware Mobile Agents Host-level tuple spaces Host-level neighbor list Severe resource limitations Limone: IP Network Middleware Mobile Agents Agent-level tuple spaces Agent-level neighbor list Resource rich 28

29 Programming Models Agilla Agilla byte code! Hosted on custom VM! Handful of well-known data types! Limone Java! Hosted on Java VM! Rich data types! 29

30 Agimone Network Architecture System Components 30

31 Agimone Services Shared data space! AgimoneAgent has own Agilla TS! Agilla agents access TS directly! AgimoneAgent wraps Agilla TS in Limone TS API! Sensor network discovery! AgimoneAgent advertises self with Limone Registry! Limone Registry distributes ad to other AgimoneAgents! Ads stored in AgimoneAgent s Agilla tuple space! 31

32 Agimone Services Inter-network Migration Multi-step process! Though internally complex, appears simple to Agilla agent developer! 32

33 Cargo Tracking Revisited Watchdog Agents! Monitors sensors! Sends alert to base station! Port authority s Limone agent reacts to it! 17 lines of Agilla code, 11 lines of Java code! Intrusion Search Agent! Searches multiple WSNs for alert tuples! Autonomously crosses WSN boundaries! 23 lines of Agilla code, no additional Java code! 33

34 Experimental Setup 100Mbps Ethernet IBM R40 Laptop 1.5GHz Pentium M 512MB RAM Windows XP 115kbps serial Mica2 Mote on Gateway 7.4MHz Atmel 128L 4KB RAM TinyOS 34

35 Performance: Agimone Services TS operations between mote and PC take ms, regardless of type or direction! Cross-WSN migration takes ~85 ms! As size of agent increases, serial link becomes bottleneck! 35

36 Performance: Middleware Overhead In-and-Out latency End-to-End Migration Latency Native implementation done using simple message passing! 27.39ms faster to move in and out of one WSN! 78.39ms faster round-trip across two WSNs! 36

37 Other Integration Frameworks Hourglass [J. Shneidman, et al. 04] and Stream-Based Overlay Networks [P. Pietzuch, et al. 06]! Routes data from WSN to Internet, but does not support applications! Tenet [R. Govindan, et al. 05]! PCs directly control sensors; no support for autonomous task migration! SERUN [J. Liu, et al. 05]! Embedded microservers control sensors; tasks cannot migrate across microservers! IrisNet [P. Gibbons, et al. 03]! Applies database abstraction to desktop PCs with sensing peripherals (e.g., webcams)! 37

38 Conclusions Agimone middleware enables integration of sensor and IP networks.! Cargo tracking application demonstrates that Agimone simplifies development.! Enhance productivity at the cost of moderate performance overhead.!! 38

39 References G. Hackmann, C.-L. Fok, G.-C. Roman and C. Lu, Agimone: Middleware Support for Seamless Integration of Sensor and IP Networks, International Conference on Distributed Computing in Sensor Systems (DCOSS'06), June Source Code Documentation Tutorials Experience Reports 39