AutoMedia: Linking the Vehicle with Consumer Electronics and Services Jason Flinn University of Michigan.

AutoMedia: Linking the Vehicle with Consumer Electronics and

Services

Jason Flinn

University of Michigan

Problem: Vehicle is an island

Each vehicle is an island unto itselfdata crosses the border generally with carried devicedevice (and its data) must be consciously managedlimited extra-vehicle networks are separate

stovepipes

Several lost opportunitiespassengers don’t have what they wantcontext which could help organize is ignoredfew existing applications don’t coordinatemany vehicular applications hard to create

Jason Flinn

Vision: Bridge the islands

Bridges to the “mainland” of home and officeunified view of all of a passenger’s mediaautomatic exchange of context and meta-dataallow individual consumer devices to come and gono effort on the part of the passengers

Bridges to the “other islands”—vehicles on the roadexchange traffic, road conditionscommunicate for immediate safety concernsform communities among co-located travelers

Jason Flinn

What’s needed?

Advances in distributed storage:Share data among home, vehicle, and web servicesCache data and propagate updates asynchronouslySupport non-traditional clients

Advances in networking:Leverage multiple networks: WiFi, WiMax, GPRS, DSRCPredict where you are goingProvide connectivity forecasts

Advances in middleware:Allow applications to declare intentionsHide vagaries of intermittent and uneven connectivity

Jason Flinn

What’s needed?

Advances in distributed storage:Shares data among home, vehicle, and mobile devicesCache data and propagate updates asynchronouslySupport non-traditional clients

Advances in networking:Leverage multiple networks: WiFi, WiMax, GPRS, DSRCPredict where you are goingProvide connectivity forecasts

Advances in middleware:Allow applications to declare intentionsHide vagaries of intermittent and uneven connectivity

Jason Flinn

Managing Data: Today

Jason Flinn

Managing Data: BlueFS

BlueFS helps manage personal data and devices

My Data

My Devices

Jason Flinn

BlueFS Goals

Pervasive data access (anytime, anywhere, any device)Support consumer electronics devices (iPod,

phone, etc.)Support web services (Flickr, Facebook, Amazon

S3, etc.)

Simplified data managementAutomation (indexing, organizing, transcoding,

etc.)Policies (reliability, privacy, etc.)Context (location, time, nearby people, etc.)

Jason Flinn

BlueFS Overview

Server stores primary replica of all data

Clients cache data to improve performanceClients register affinity for specific types of dataCached data available when disconnected

Jason Flinn

Device-Specific Protocol

Connecting Consumer Electronics

CEDs cannot perform DFS protocol

DFS Protocol?

Distributed File System

Device-Specific Protocol

Attach: computer speaks for CEDWorks with disconnected clients

DFS Protocol

Jason Flinn

Device-Specific Namespaces

User prefers one organization

Consumer electronics device requires another organization

Solution: Store translations on the consumer device

Classical

Jazz

F01

F02

F03

F04

Jason Flinn

Adding Automation

Updating indexes

Transcoding

Type-specific caching

Organizers

Jason Flinn

Adding Automation

Cannot execute on CED

Leverage general-purpose computersTake action when files change

Problem: Need notification of file changesJason Flinn

Notification Via Persistent Queries

Don’t need new mechanism

Leverage cache consistency mechanismStructure notifications as file system objectRobust to crashHandles disconnected operation

updates

truncate

read process*.mp3

Jason Flinn

.TiVo

.mp4

Persistent Queries

Example: video recording and playback

FileServer

VideoTranscoder *.TiVo

.mp4

.mp4

.TiVo

*.TiVo .TiVo

.mp4

Jason Flinn

Leveraging intra-vehicle context

Vehicle has a wealth of contextual data

Can we provide a “context bus” that enriches data?

Enrich data by sharing context among local devices:vehicle location used to tag site where photos taken

Allows searching by locationCan automatically organize digital photo albums

Wireless proximity of cell phones reveals user presence

Match music on stereo to tastes of passengersStart playing audio-book where left off last time

Jason Flinn

What’s needed?

Advances in distributed storage:Shares data among home, vehicle, and mobile devicesCache data and propagate updates asynchronouslySupport non-traditional clients

Advances in networking:Leverage multiple networks: WiFi, WiMax, GPRS, DSRCPredict where you are goingProvide connectivity forecasts

Advances in middleware:Allow applications to declare intentionsHide vagaries of intermittent and uneven connectivity

Jason Flinn

The Big Picture

State of the art: systems are reactive not proactive

There are opportunities to planpeople are creatures of habitinfrastructure is slow to change

If the system knewwhere you were likely to be, andwhat connectivity was available there...

...then applications could schedule their usage appropriately

Our goal: expose this connectivity derivative to applications

Jason Flinn

Pieces of the puzzle

Where are you likely to be?figure out where you are nowuse the past to predict where you’ll be next

What are conditions likely to be when you get there?map access points at newly-visited locationsrefresh infrequently to catch stale state

Expose this information to applicationssimple API: expected bandwidth in 10 (20, 30, ...)

secondsapplications use this however they like

Jason Flinn

Where are you?

Existing solutionsGPS when you canWiFi localizationGSM fingerprinting

Our implementation: PlaceLab/WiFi20-30 meter avg accuracyacceptable for our needs

Convert to a discrete gridlimit precision of lat/longrid square ~110x80 meterscompact, useful representation

Jason Flinn

Where are you going?

We need a personal mobility modelpeople are creatures of habit, but......different people have different habits

Song et. al. (Dartmouth) conducted a bake-offwinner: second-order Markov model

Model consists of discrete states and transitionsstates: your current and former locationtransitions: possible next states, with probabilities

assignedprobabilities computed by past behaviordiscrete transition steps: we use 10 seconds

(arbitrary)

Jason Flinn

What will conditions be like?

Overlapping public coverage

Heterogeneous qualityBandwidth, latency, ports

Decentralized ownership

Multiple “usable” options

Which AP is the best AP?

Jason Flinn

Virgil AP selection daemonCurrent mechanism: loudest must be best

okay in a homogenous deploymentno better than random selection in the wild

Instead, we perform active testing and discoveryScan for APs and associate to each in turnRun bandwidth, latency, port tests to reference

serverChoose AP with the “best” connectionCache test results for future prediction

Jason Flinn

History is useful

Repeated traversals of the same area benefit (a lot!)

0.0

2.5

5.0

7.5

10.0

12.5

15.0

Lap 1

Lap 2

Lap 3

Lap 4

Lap 5

iwlist scan

Lap 1 Lap 2 Lap 3 Lap 4 Lap 50%

5%

10%

15%

20%

25%

random

SSS

Virgil

History: % scans finding usable AP

History: scanning overhead (s)

Jason Flinn

The Commute

Jason Flinn

Connectivity Forecasts

Close is often good enough, thanks to range issues

Jason Flinn

What’s needed?

Advances in distributed storage:Share data among home, vehicle, and mobile devicesCache data and propagate updates asynchronouslySupport non-traditional clients

Advances in networking:Leverage multiple networks: WiFi, WiMax, GPRS, DSRCPredict where you are goingProvide connectivity forecasts

Advances in middleware:Allow applications to declare intentionsHide vagaries of intermittent and uneven connectivity

Jason Flinn

Declarative Networking

Allow applications to declare their intent in using network.

Main goal: simplicity of the interface.

Applications specify:Foreground (latency-sensitive) vs. backgroundBulk vs. small messagesImportant vs. unimportantetc.

May specify on a per-message, per-socket, or per-thread basis.

Jason Flinn

Connectivity middleware

Manage vagaries in network connectivity:Transient networks (WiFi hotspots)Intermittent networks (cell coverage)Changes in latencyVarying bandwidth

Challenge: map application sends/receives to networksChoose best network for each requestDefer traffic when necessary, continue when availableAllow applications to tear-down, re-establish connections

Jason Flinn

Declarative networking example

Read mail(foreground)

High availabilityLow bandwidth

IntermittentHigh bandwidth

Download mail(background)

Jason Flinn

Building Bridges

Advances in distributed storage:Share data among home, vehicle, and mobile devicesCache data and propagate updates asynchronouslySupport non-traditional clients

Advances in networking:Leverage multiple networks: WiFi, WiMax, GPRS, DSRCPredict where you are goingProvide connectivity forecasts

Advances in middleware:Allow applications to declare intentionsHide vagaries of intermittent and uneven connectivity

Jason Flinn

Thanks to…

T.J. GiuliBrett HigginsAnthony NicholsonBrian NobleDan PeekVenkatesh PrasadAzarias RedaDavid Watson

Jason Flinn