hoi uncertain substancepresentation

UNCERTAIN SUBSTANCETOM KEENEA part of the Hands-On Ideas series

September 4th 2013

www.theanthillsocial.co.ukArtist who critically engages with technology.

Worked with bacteria, face recognition, participatory/community arts.

Self taught programmer & maker: wood, metal, electronics.

MA in Interactive Media: Critical Theory & Practice in 2012, Goldsmiths University, London.

InspirationWirelessness “Radical Empiricism in network cultures”: Adrian Mackenzie.

Open Systems Association (OSA)www.opensystem.org.uk

YoHa: Graham Harwood + Matsuko Yokokoji. www.yoha.co.uk

Evil Media: Matthew Fuller and Andrew Goffey.www.yoha.co.uk/sites/yoha.co.uk/evilmedia

What I wanted to exploreHow an algorithm is able to construct the world we live in.

How it operates outside of any design intent.

A different concept of control.

An open ended process led methodology – make mistakes.

Uncertain Substance: The Viterbi AlgorithmAn algorithm searches radio waves looking for conversations about money

About the projectExplored the history of the algorithm.

Attempted to understand the mathematics.

Built contraptions/devices as a means to reveal how it operates: - Primitive transmitter. - Software defined radio. - Speech recognition system.

Abstract•The probability of error in decoding an optimal convolutional code transmitted over a memoryless channel is bounded from above and below as a function of the constraint length of the code. For all but pathological channels the bounds are asymptotically (exponentially) tight for rates aboveR_{0}, the computational cutoff rate of sequential decoding...•Viterbi, A.J. 1967

Convolutional encoding

Add bit “e” to beginning, shift bits to right and discard last “0”.←

← Add “x” drop “0”.

← Add “a” drop “0”.

← Add “m” drop “0”.

← Add “p” drop “e”.

← Add “l” drop “x”.

← Add “e” drop “a”.“000000e000xe00axe0maxepmaxlpmaelpm”Transmit:

(shift register)

Decoding Trellis

Like talking across a noisy room

Because we know grammarwe can decipher what is said without hearing every word or letter.

The Viterbi will search for a particular structure of data and is able to take a guess based on the current available information.

Harry GrindellMatthews Early experimenter in wireless communications.

Patented worlds first mobile phone in 1909.

And the Death Ray in 1924 which he possibly sold to the French...

Spark gap transmitters.

Used £10 USB TV Tuner with GNU Radio, a SDR system.

Read about on hackaday:http://bit.ly/1a3Yrpg

Linux build Instructions:www.theanthillsocial.co.uk/sketch/207

Software Defined Radio (SDR)

www.github.com/csete/gqrx Enables audience to easily see FM/Other tuning.

GQRX: Frontend for GNU radio

CMU Sphinx: Open Source Toolkit For Speech Recognition. www.cmusphinx.sourceforge.net

Likes the word “money”Hacked phython code: www.theanthillsocial.co.uk/projects/uncertain-substance

Voice Recognition

CCTV

Post-Project

Further experimentation

Miniaturisation: What potentials are revealed when the system is made smaller?

Social output: Buying shares, setting a price on a commodity.

Exploring other uses of the Viterbi.

How you can build off my work

The technological:- Improved speech

- recognition.- Tune into TV.- Install on small devices.

The theoretical:- Investigate the dull grey & boring.- Think about technological objects as complex assemblages.

Questions and Answers