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Constructing Locally Centralized Applications by Mobile

Agents in Wireless Sensor Networks

2008/05/14Shunichiro Suenaga* (Nihon Unisys Ltd./The Graduate University for Advanced Studies)Shinichi Honiden (The University of Tokyo/ National Institute of Informatics)

ATSN-2008

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Index

1.Overview

2.Problems and Requirements

3.Approach

4.Evaluation

5.Related Work

6.Conclusions

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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)

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2. Problems and Requirements

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2.1. Assumed Environment

WSN (roof)

Base Station

LAN

Stock Management

• Warehouse• Goods: Arrival/ Relocation/ Shipping• “Stock Management” manages locations of goods.

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2.2. Locally Centralized Application

Temp. Monitoring Intruder Detection

+ Goods location sometimes change

Addition and Deletion

(Arrival and Shipping)

Specific processing for each goods.

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2.3. Requirements① 　 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.

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Reprograming VS MA　 Addition and Deletion of Programs　 Specific Node Reprogram

Update ！ Update ！

Bottle-neck!

Base-Station Base-Station

Reprogramming Mobile Agent

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2.4. 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

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Unsophisticated agent architecture introduces following possibilities

Disrupts periodical sensing Makes Light weight agent heavy

2.4. Problem ① （ Architecture)

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2.4. Problem (Group Migration) ②

Migration failure makes application execution impossible

Individual migrations of agents introduce following possibility

・　 Lost

・　 Fall awayCan’t continue execution

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3. Approach

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3.1 Approach (Architecture)①

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.

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3.1 Approach (Architecture)①Name Description

C) Master Judgment of the sensing results,

Application specific processing,

Group Migration, management of the lifecycles of Slave-S,Slave-M.(Approach② ）

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

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3.1 　Approach① （ Architecture ） LCA (Wine Example)

When wine moves, group also needs to move..

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3.2 Approach (Group Migration)②■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.

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3.2 Approach (Group Migration)②

• 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

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3.2 Approach (Group Migration)②

1. Master Injected

2. Slave Deployment

3. Start

4. Slave Killed

5. Migration

6. Deployed

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3.3 Approach② （ 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)

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3.4 Implementation

• We extended Agilla (ICDCS 2005)

Points

• Hierarchy (Master,Slave)

• Location Management

• Kill Manager

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Evaluation

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4.1 Evaluation

① Architecture- Scenario base

- Drawbacks of our approach

success rate of kill

② Group Migration- 　 Success rate of migration

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4.2 Simulation Setting

TOSSIM 　・　 Topology ：　 grid

・　 size ：　 8x8

・　 baud rate ：　 40Kbps

・ Lossy ： 5feet, 8feet,10feet

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4.3 Evaluation (1/3)①Scenario(How many times can a group execute processin

g 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 st

ation• Slave-M obtains the new location of goods• Group start to migrate to the new location.

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4.3 Evaluation (2/3)①

5feet 8feet 10feet

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%

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%

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4.3 Evaluation (3/3)①

5feet 8feet 10feet

Success rate of Kill 90.9% 68.6% 52.4%

Success rate of Kill

(Retransmit)

100% 100% 100%

Slaves can be killed completely in simulation environment.

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4.4 Evaluation (1/2② ）• 4-times Group Migration• Agilla (three agents)• Our Approach （ 1Master→Master,SlaveS,Slave

M ）

5lossy 8lossy 10lossy

Agilla 3.46 3.0 2.66

80% 60% 40%

Our Approach

4.0 3.73 3.66

100% 80% 67%

Spatial distance of agents are 1hop

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4.4 Evaluation (2/2② ）

5lossy 8lossy 10lossy

Agilla 2.86 2.06 1.2

53.3% 26.6% 13.3%

Our Approach

4.0 3.4 3.2

100% 73.3% 60%

Spatial distance of agents are 2hop

• 4-times Group Migration• Agilla (three agents)• Our Approach （ 1Master→Master,SlaveS,Slave

M ）

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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

　

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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

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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.

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Thank you !

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Appendix

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2.1. Assumed Environment• “Stock Management” manages locations of

goods. • WSN is

① 　 Arrival ② Relocation ③ Shipping

Shelf ID Shelf ID

Link goods ID and shelf ID

Link goods ID and shelf ID(Relocation)

Delete shipped goods ID

Stock ManagementWi-Fi

Shipping ID

PDA

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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

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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..

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Sample Code