1 Constructing Locally Centralized Applications by Mobile Agents in Wireless Sensor Networks 2008/05/14 Shunichiro Suenaga* (Nihon Unisys Ltd./The Graduate University for Advanced Studies) Shinichi Honiden (The University of Tokyo/ National Institute of Informatics) ATSN-2008

2 Index 1.Overview 2.Problems and Requirements 3.Approach 4.Evaluation 5.Related Work 6.Conclusions

3 Overview When an application is constructed by multiple agents, existing works have problems –Architecture –Group Migration We propose –Architecture (Three different role of agents) –Group Migration (Agent generation)

4 2. Problems and Requirements

Assumed Environment WSN (roof) Base Station LAN Stock Management Warehouse Goods: Arrival/ Relocation/ Shipping “Stock Management” manages locations of goods.

Locally Centralized Application Temp. MonitoringIntruder Detection + Goods location sometimes change Addition and Deletion (Arrival and Shipping) Specific processing for each goods.

Requirements ① Spatial sensing around the goods. （ multiple programs are needed to cover spatial area ） ② Programs can move to the new location (of the goods) and continue the processing ． Existing Works ） Reprogramming (Deluge, Mate) and Mobile Agent (Agilla,Actornet) can realize addition and deletion of programs in a WSN.

8 Reprograming VS MA Addition and Deletion of Programs Specific Node Reprogram Update ！ Bottle- neck! Base-Station ReprogrammingMobile Agent

Problems ① Architecture to constructing LCA (Locally Centralized Application ) by multiple mobile agents ② Simultaneous Group Migration to move to the new location of the goods

10 Unsophisticated agent architecture introduces following possibilities  Disrupts periodical sensing  Makes Light weight agent heavy 2.4. Problem ① （ Architecture)

Problem ② (Group Migration) Migration failure makes application execution impossible Individual migrations of agents introduce following possibility ・ Lost ・ Fall away Can’t continue execution

12 3. Approach

Approach ① (Architecture) LCA Requirements A) Sensing Execution of sensing on several nodes. B) Information collection Exchange of information between base station. C) Application specific processing judgment of the sensing results, execution of the processing in each specific situation.

Approach ① (Architecture) NameDescription C) Master Judgment of the sensing results, Application specific processing, Group Migration, management of the lifecycles of Slave-S,Slave-M.(Approach ②） A) Slave-S Sensing around the goods. Multiple Slave-S are deployed in a group. S: Sensing / Stationary B) Slave-M Master gives an order to information collection Slave-M. (Information Exchange between node and base station) M: Mobile

Approach ① （ Architecture ） LCA (Wine Example) When wine moves, group also needs to move..

Approach ② (Group Migration) ■Success Rate of migration (existing works) P: Failure rate （ common in WSN ） N: number of programs Success Rate= (1-P)^N Decreasing N is a solution Slave-Ss and a Slave-M are included in Master code. Our Approach: Make N 1.

Approach ② (Group Migration) Slave-S ， Slave-T are included in Master Master generates Slave-S and Slave-T Mote Middle Mote Middle Migration Transmitted transformed Re-generation transformed

Approach ② (Group Migration) 1.Master Injected 2.Slave Deployment 3.Start 4.Slave Killed 5.Migration 6.Deployed

Approach ②（ Group Migration) ■ Deployment Pattern (Static) -number of Slaves -Deployment Pattern -All Surrounding node -N-Hop ■ Static Deployment Pattern Example - 4 Slave-S are deployed on 4 of 1hop neighbors. - 1 Slave-M is deployed on 1 of 1hop neighbors. Optimization and Dynamic Deployment are Future Work Where are Slave-S and Slave-M deployed ? (Specified in Master code)

Implementation We extended Agilla (ICDCS 2005) Points Hierarchy (Master,Slave) Location Management Kill Manager

21 Evaluation

Evaluation ① Architecture - Scenario base - Drawbacks of our approach success rate of kill ② Group Migration - Success rate of migration

Simulation Setting TOSSIM ・ Topology ： grid ・ size ： 8x8 ・ baud rate ： 40Kbps ・ Lossy ： 5feet, 8feet,10feet

Evaluation ① (1/3) Scenario (How many times can a group execute processing around the goods? ) Master moves to the new location Master deploys 4 Slave-S to 4 of 1hop neighbors Master deploys 1 Slave-M to 1 of 1hop neigbors ． Master gives an order to Slave-M to go to base station Slave-M obtains the new location of goods Group start to migrate to the new location.

Evaluation ① (2/3) 5feet8feet10feet 2times-Our Approach 2times-Agilla 100% 73.3% 93.3% 60.0% 73.3% 33.3% 3times-Our Approach 3times-Agilla 93.3% 53.3% 73.3% 40.0% 20.0% 4times-Our Approach 4times-Agilla 93.3% 33.3% 66.7% 20.0% 40.0% 6.8% 5times-Our Approach 5times-Agilla 86.6% 26.7% 60.0% 13.3% 33.3% 0%

Evaluation ① (3/3) 5feet8feet10feet Success rate of Kill90.9%68.6%52.4% Success rate of Kill (Retransmit) 100% Slaves can be killed completely in simulation environment.

Evaluation ② (1/2 ） 4-times Group Migration Agilla (three agents) Our Approach （ 1Master→Master,SlaveS,SlaveM ） 5lossy8lossy10lossy Agilla %60%40% Our Approach %80%67% Spatial distance of agents are 1hop

Evaluation ② (2/2 ） 5lossy8lossy10lossy Agilla %26.6%13.3% Our Approach %73.3%60% Spatial distance of agents are 2hop 4-times Group Migration Agilla (three agents) Our Approach （ 1Master→Master,SlaveS,SlaveM ）

29 Summary of Evaluation ① Architecture –Architecture looks fair –Disadvantage is overcome in simulation environment ② Group Migration –Our approach has better success rate than existing work

30 Related Work ■ WSN Reprogramming (Deluge, Mate ， XNP, MNP ， FireCracker) –code mobility WSN-MA (Agilla,ActorNet,SensorWare) –group migration ■ Wired Network MA(Mobile Space,Ishikawa et al. ） Assumed Environment purpose

31 Conclusions We propose, Architecture and Group Migration We show the efficiency of our approach in simulation environment Our approach will be one of the solutions to realize multiple simultaneous applications in WSNs.

32 Thank you !

33 Appendix

Assumed Environment “Stock Management” manages locations of goods. WSN is ① Arrival ② Relocation ③ Shipping Shelf ID Link goods ID and shelf ID (Relocation) Delete shipped goods ID Stock Management Wi-Fi Shipping ID PDA

35 Limitation Migration Failure of Master –makes application execution impossible –while, existing work also has this problem Ignore Execution State of Slaves –Our approach always kill Slaves –Not required in assumed application

36 Future Work Dynamic acquisition of Deployment Pattern Now: Middleware deploys Slaves in according to the static deployment pattern Future: Master can adopt the situation, i.e. battery level, link state, number of neighbors, etc..

37 Sample Code