a computational space for the web of things

A Computational Space for the Web of Things 3rd International Workshop on the Web of Things (WoT 2012), Newcastle, UK

Simon Mayer, Distributed Systems Group, ETH Zurich, simon.mayer@inf.ethz.ch

David S. Karam, Chair of Scientific Computing, TU Munich, karam@in.tum.de

Motivation / Background

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Earthquake and Tsunami on March 11, 2011

Nuclear meltdown in three reactors of the Fukushima NPP

Releases of radioactive materials

www.pref.fukushima.jp

US federal occupational limit: 0.5 μSv/h

Motivation / Background

“Wind from Fukushima” App Mashing of radiation and wind data

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Cheap Geiger

counters

Radiation data

streams

Motivation / Background

Apps like “Wind from Fukushima” allow to mashup this data to provide a service

What happens with the refined data? 4 WoT 2012: 3rd International Workshop on the Web of Things 7/13/2012

Commodity Hardware

Information Markets

Motivation / Background

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Commodity Hardware

Information Markets

Computational

Markets

Crowd-sourced information creation

Information sharing and aggregation

Information processing, refinement, and analysis

Motivation / Background

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Commodity Hardware

Information Markets

Computational

Markets

Crowd-sourced information creation

Information sharing and aggregation

Information processing, refinement, and analysis

Cosm, Sen.Se, Twitter, FB Graph API, ...

Smartphones, Smart Consumer Products, Electricity Meters, ...

computational marketplace

Algorithms should be linked together in an open and extensible fashion to enable multi-tier computations in a construct that we call a

Constraints on a Computational Marketplace

Clients need to be able to find computations on the

marketplace and select appropriate computations to achieve their goal

The marketplace should provide meta-information about algorithms and thus help to optimize traversal

Mechanisms required for security and billing

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Constraints on a Computational Marketplace

Clients need to be able to find computations on the

marketplace and select appropriate computations to achieve their goal

The marketplace should provide meta-information about algorithms and thus help to optimize traversal

Mechanisms required for security and billing

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Interface Discovery

Marketplace API exposes paths

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GET marketplace/node_arrhythmia

{

“service” : “www.arrhythmia_detection.net”

“forward_paths” : {

“emergency” : “node_dispatch”,

“default” : “node_start_arrhythmia”

}

}

Interface Discovery

Marketplace API exposes paths

“Graph Crawler” maps computational graph Basically an ordinary search machine…

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Crawler

GET marketplace/node_arrhythmia

{

“service” : “www.arrhythmia_detection.net”

“forward_paths” : {

“emergency” : “node_dispatch”,

“default” : “node_start_arrhythmia”

}

}

Constraints on a Computational Marketplace

Clients need to be able to find computations on the

marketplace and select appropriate computations to achieve their goal

The marketplace should provide meta-information about algorithms and thus help to optimize traversal

Mechanisms required for security and billing

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Path Traversal Guidance

Humans do it...

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Path Traversal Guidance

Machines can, too!

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Path Traversal Guidance using Path Deciders

Application-specific (here: Arrhythmia Detection)

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Path Traversal Guidance will work if...

Machines can understand and interpret path names Long shot, but could work... Definitely future work!

Path descriptions (e.g., “emergency”) are fixed/meaningful Easy!

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Constraints on a Computational Marketplace

Clients need to be able to find computations on the

marketplace and select appropriate computations to achieve their goal

The marketplace should provide meta-information about algorithms and thus help to optimize traversal

Mechanisms required for security and billing

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Computational Paths Optimization

Optimize traversal according to application needs

Multi-dimensional cost metrics: time, money, quality,...

Marketplace offers this information, but does not decide on

routes → Generic path deciders

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Computational Paths Optimization using Path Deciders

Generic (here: Lowest time cost path)

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Constraints on a Computational Marketplace

Clients need to be able to find computations on the

marketplace and select appropriate computations to achieve their goal

The marketplace should provide meta-information about algorithms and thus help to optimize traversal

Mechanisms required for security and billing

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Security and Billing

Authentication, authorization, and billing schemes to

restrict access to computational resources

Don’t create a centralized repository for login data: trust problems, security problems, scaling problems...

Instead use third-party schemes (OAuth 2.0!) and inline this functionality as a linked computational node!

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Demo 1: Arrhythmia Patient Scenario

Four separate computational mashups Arrhythmia Arrhythmia probability from heartbeat data Ambulance Optimal ambulance dispatch Traffic Predicts traffic from location of people and cars and weather data from yahoo/google predict

Composite mashup: Weather + Traffic + Ambulance +

Arrhythmia OAuth-based authentication for prediction API

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Demo 2: Marketplace Exchange

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Time cost-based traversal optimization of multiple clients Uses generic time-cost-based path decider...

Three arrhythmia detectors: 𝐶𝐶𝐶𝐶𝑖 = 𝑑 + 𝑘 ∗ #𝑐𝑐𝑐𝑐𝑐𝐶𝐶𝑖

Demo 2: Marketplace Exchange

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Time cost-based traversal optimization of multiple clients Uses generic time-cost-based path decider...

Three arrhythmia detectors: 𝐶𝐶𝐶𝐶𝑖 = 𝑑 + 𝑘 ∗ #𝑐𝑐𝑐𝑐𝑐𝐶𝐶𝑖

Conclusion

Concept of computational marketplace

Constraints for scalable, fault-tolerant, and change-tolerant

N-tiered computational model

Proof of concept marketplace implementation + scenarios

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Acknowledgements

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