Communicating in Wales: design and architecture for mobile applications over poor connectivity

Alan Dix

http://alanwalks.wales/

Tiree

Tiree Tech Wave26-30 Oct 2017

University ofBirmingham

today I am not talking about …

• physicality and product design

• long tail of small data

• community technology

• intelligent internet interfaces

• digital humanities

• creativity and Bad Ideas

• visualisation and sampling

• situated displays

• virtual crackers and slow time

• modelling dreams and regret

• the emergence of self

not to mention …

REF

I am talking about …

connectivity

… or the lack of it!

poor connectivity

three aspects:

• user experience

• architecture and infrastructure

• policy

… but first a little about a walk

walking Wales

1058 miles (1700 km) around around the margins of Wales

Welsh Coast Path

opened May 2012

linking existing paths

a single way marked route

with Offa’s Dyke encircles Wales

three full traversals in 2012 (one running)

vision

personal

encircling, encompassing, pilgrimage, homecoming,

practical

IT for the walker & IT for local communities

philosophical

reflections on walking and space, locality and identity

research

personal agenda and living lab

no hard boundaries

research – practicepersonal – philosophical

19th century science or Mediaeval?

walking Wales

technology

me: “what technology do you use?”walker: “a map”

the best technology!

voice recorder

real buttons!!

use it while moving

while walkingactive

camera, recorderpassive

GPS, ECG, EDA

when stoppediPad, blog, flickr,

social media,uploading data

before/afterweb for planningnew contacts on

Twitter, emailreporting, analysis

while walkingother walkers

occasional friends/family

meeting

when stoppedshop keepers,

B&B proprietors,chance meetings

talks, visits

before/afterfamily and friends,

readers, researchers,

future walkers

socialsphere

technicalsphere

data

location

GPX ... batteries ... sporadic signals ....

bio-sensing

ECG (heart), EDA (skin) and accelerometers

audio and images

in the moment

text

after the event

implicit

explicit

user experienceconnectivity problems

I expected it to be bad ...

but it was worse

... not a recent issue ...

not just jerky movies ...

Software Update 2.3Gbsecurity patch

software makes it worse ...

Twitter 140 chars ...

but unusable with poor signal

email slow but works – 1970s technology

Flickr uploader freezes on poor connections

... even in Paris!

✔

✗

✗

user experienceprinciples

time matters

timescales

ms secs mins hours days

local interaction + syncronisation

store & forward

hand-eyecoordination

split-feedbacksyntactic/semantic

local feedbackpre-compute

requestresponse session

vocabulary … just words?

bandwidth … how much

delay … how long

jitter … how variable

glitches

frequency

length of drop

ms secs mins hours days

ms

secs

mins

hours

days

totalfailure

jitter

intermittentconnectivity

glitches

principles

store and forward… in an age of instant

restarting after problems

connectivity-aware applications also cost, energy, etc. e.g. rich media

architecture& infrastructure

the bits leak out

recall …software makes it worse ...

Twitter 140 chars ...

but unusable with poor signal

Flickr uploader freezes on poor connections

... even in Paris!

N.B. both as in 2013

Twitter experience

Twitter – why?

code (on start)

– read news-stream

– build UI

– allow tweets

https://dev.twitter.com/rest/reference/get/statuses/home_timeline

https://dev.twitter.com/rest/reference/get/statuses/home_timeline

5 pages later …

$ wc one-tweet.json

163 304 4468

https://dev.twitter.com/rest/reference/get/statuses/home_timeline

Twitter – why?

code (on start)

– read news-stream

– build UI

– allow tweets

could be

– asynchronous load

– lightweight version of API

140 chars = 5-10K in JSON/XML API

50 items (server performance)50 x 5-10 K = 0.25–0.5 Mbyte… on 2 bars of GSM!

Flickr experience

on desktop:

– select required files

– categorise and tag

on send

– starts to work

– failure

– some files uploaded, but untagged

– no ability to restart

Flickr– why?

code (on send)– upload all images

– tag all images

could be– build to-do list

– for each item in to-do list• upload and tag

– on restart: pick up last to-do-list …

on fail exit but save to-do list

on fail exit

software architecture

asynchronous interactions

distributed system not thin client

– synchronisation technology – inc. partial sync.

think local connectivity –

– e.g. Qraqrbox (cf. www paper)

think failure / restart

– e.g. to-do list based coding

protocols

IP slow start

– resilient to nuclear war… but not Tiree or Wales coast

DNS failure caching

why glitches???

router overload ?

policy

the netprivilege of the rich

or service for all

always connected?

mobile signalabsent or weak

broadband ...not so broad

masts point to seanot land ...yachts = money

https://explore.ee.co.uk/coverage-checker

infrastructure or privilege?

what is the greatestBritish invention?

infrastructure or privilege?

19th century – Penny Post

the amazing invention

revolutionised communication

Today – Internet

2013 – 50% of Welsh schools said

poor connectivity hampers education

2017 – 7 out of 20 worst connected areas in UK …… in Wales

http://www.victorianweb.org/history/pennypos.html

nudge, nudge

mobile mast charging

– similar to European roaming

– change cost-benefit for companies

– allow more community masts

ISPs & local communities

– Tiree local traffic goes to London and back!

glitches?

no official word for it!

=> not in agreementsnot in contracts

not noticed …… unless you have to live with it

in summary

user experience– on-going issue

– impact for individuals, business and education

policy– root cause – privilege or public service?

– vocabulary matters

architecture– good design ameliorates poor infrastructure