www.dvs1.informatik.tu-darmstadt.de

Workflow Support forWireless Sensor and Actor

Networks

Technische Universität Darmstadt, Germany

Pablo Guerrero

PhD ProgramEnabling

Technologiesfor E-Commerce

Daniel Jacobi

PhD ProgramMixed Mode

Environments

Alejandro Buchmann

Databases and Distributed Systems

Group

International Workshop on Data Management for Wireless Sensor Networks

September 24th 2007, Vienna, Austria

2

Application Logic Evolution

Environment

DataSampling

DataInterpretation

DataCollection

Observations

3

First Generation Applications

Observations

Great Duck IslandGlacsWebDutch Potatoes

Push raw data out of the network as reliably as possible

Data

4

Application Logic Evolution

Environment

EventDetection

Observations

DataInterpretation

DataCollection

DataSampling

5

Structural MonitoringVolcán Reventador

Second Generation Applications

Observations

Sample, compare with threshold and send

Data

Event

6

Application Logic Evolution

Environment

Observations

DataInterpretation

Actuation

DataCollection

EventDetection

DataSampling

InterestDissemination

7

Chemical Drums Storage

Third Generation Applications

In-network interpretation

Coastal Redwoods

Observations

Data

Event

Interest

8

Actuation

ActuationDissemination

DecisionMaking

DataInterpretation

EventDetection

DataCollection

Data Sampling

InterestDissemination

Application Logic Evolution

Environment

Observations

9

Research Focus

Observations

MAC

RoutingLocalizatio

n

Time Sync StorageCaching

TinyOS/NesC SOS

Regiment

Hood

Kairos

TAGCougar

TinyDB

Maté Agilla

ATaG

CosmosWorkflo

ws

GRA

ScopesAbstract Regions

10

A Workflow Approach

Support domain experts in programming WSAN apps

Rationale: Easy for domain experts Broad expressiveness

Approach: Application logic defined through CASE tools WSAN runs Workflow Engine Middleware

Benefits: Extensive verification &

validation models Faster reaction to event

ObservationsWorkflow Approach

S0 S1S2

S3S4 S5

S6

11

Composing a WSAN Workflow Program

States Transitions

Event Action Roles

Static/Dynamic

S DF,

R1

A, R2

R3R1

ObservationsWorkflow ApproachProgram Composition

R2

12

A Workflow Execution Engine

Similar to Mealy machine (Input, Output) Multithreading (Choice, Join)

S0 S1

S2

S3

S4 SFF1,R1 | AX,R2

R3R1

R2

F2,R1 | AY, R1

F3,R2 | AY,R3

F2,R2 | -

F2,R3 | Az,R3

- | Az,R3

ObservationsWorkflow ApproachProgram CompositionWorkflow Engine

13

Research Directions / Discussion

Instantiation of the current WF Language Extension of WF Language primitives

Inclusion of Conditions in transitions Extend with WF Patterns

Distributed WF Execution Reliability vs. Scalability

WF Composition and updates Multiprogramming Logging

Visibility Security …

ObservationsWorkflow ApproachProgram CompositionWorkflow EngineDirections

14

Conclusions

New app. generation requiring finer actuation control

Workflow approach to define application logic Support for in-network actuation

Language to describe application logic defined Centralized workflow execution engine Ongoing work, many directions

Directions ConclusionsObservationsWorkflow ApproachProgram CompositionWorkflow Engine

15

Workflow Support for WSANs

The End

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Directions ConclusionsObservationsWorkflow ApproachProgram CompositionWorkflow Engine End