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Artificial Intelligence: from Computer Science to Molecular Informatics

Joost N. Kok

Artificial Intelligence

 Movie Artificial Intelligence by Steven

Spielberg

 Five year studies at universities of Utrecht,

Amsterdam, Groningen and Maastricht

Artificial Intelligence

 The concept that machines can be improved to assume some capabilities normally thought to be like human intelligence such as learning, adapting, self-correction, etc.

 The extension of human intelligence through the use of computers, as in times past physical power was extended through the use of mechanical tools.

Artificial Intelligence

 On May 11, 1997, an IBM computer named

Deep Blue whipped world chess champion

Garry Kasparov in the deciding game of a sixgame match

Artificial Intelligence

 First Robot World Cup Soccer Games held in

Nagoya, Japan in 1997

 Goal: team of robots beats the FIFA World

Cup champion in 2050

Artificial Intelligence

 Alan Turing

 Turing Award

 Turing Machine

 Turing Test

Artificial Intelligence

 Turing Test

Artificial Intelligence

 Natural language processing: it needs to be able to communicate in a natural language like English

 Knowledge representation: it needs to be able to have knowledge and to store it somewhere

 Automated reasoning: it needs to be able to do reasoning based on the stored knowledge

 Machine learning: it needs to be able to learn from its environment

Artificial Intelligence

 Turing Machine

Time Complexity

 Turing machine gives notion of computability

 Time complexity: how many steps does it take to find an answer?

 Combinatorial Explosion

 Problems that are computable in polynomial time (class P)

 Problems that are verifiable in polynomial time (class NP)

 P equals NP ?

Natural Computing

 Computing carried on or inspired by (gleaned from) nature

Natural Computing

 Computers are to Computer Science as

Comic Books to Literature (Joosen)

Natural Computing

 Natural Computing

– Evolutionary Computing

– Molecular Computing

– Gene Assembly in Ciliates

Evolutionary Computing

Evolutionary Computing

Initialize population, evaluate

(terminate) select mating partners select survivors evaluate recombine mutate

Examples

 Evolutionary Art

 Nozzle

Example: Discrete Representation

 Genotype: 8 bits

 Phenotype:

– integer

1*2 7 + 0*2 6 + 1*2 5 + 0*2 4 + 0*2 3 + 0*2 2 + 1*2 1 + 1*2 0

= 163

– a real number between 2.5 and 20.5

2.5 + 163/256 (20.5 - 2.5) = 13.9609

– schedule

Example: Mutation before 1 1 1 1 1 1 1 after

1 1 1 0 1 1 1

mutated bit

Mutation happens with probability p

m

bit for each

Example: Recombination

 Each chromosome is cut into 2 pieces which are recombined cut cut

1 1 1 1 1 1 1 0 0 0 0 0 0 0 parents

1 1 1 0 0 0 0 0 0 0 1 1 1 1 offspring

.

Example: Fitness proportionate selection

 Expected number of times f i equals f i

/ average fitness is selected

 Better (fitter) individuals have:

– more space

– more chance to be selected

Best

Worst

Evolutionary Computing

Initialize population, evaluate

(terminate) select mating partners select survivors evaluate recombine mutate

Molecular Computing

Molecular Computing

 Implementation of algorithms in biological hardware, e.g. using DNA molecules and enzymes

 Power lies in massive parallel search

 Test tube may contain easily 10 15 strands of

DNA

 Compared to computers very efficient in energy consumption, storage density and number of operations per second

Molecular Computing

Molecular Computing

 DNA: sequence of nucleotides linked together by strong backbone

 Nucleotides have attached bases A, T, C, G:

– Adenine

– Thymine

– Guanine

– Cytosine

 Watson-Crick complementarity A-T C-G

Molecular Computing

Hamiltonian path problem

in out

Molecular Computing

 Algorithm

– generate random paths through graph

– keep only paths from the initial to the final node

– keep only paths that enter exactly n nodes

– keep only paths that enter all nodes

– if any paths remain, the graph contains a

Hamiltonian path

Molecular Computing

 For each node, take unique random sequence over A, C, T, G

 For each node, the sequence is of the same length

Molecular Computing

 For every connection, construct a sequence from the sequences of the two nodes

– Node 1: TATCGGATCG GTATATCCGA

– Node 2: GCTATTCGAG CTTAAAGCTA

 Inverse: GTATATCCGA GCTATTCGAG

 Sequence: CATATAGGCT CGATAAGCTC

Molecular Computing

 Generate random paths through graph

– Mix strings for all nodes with strings for all arrows, together with Ligase enzyme

Molecular Computing

 Apply PCR (Polymerase Chain Reaction) amplification using as primers string for in and complement for string out

Molecular Computing

 Select molecules that encode paths that enter exactly n nodes by running contents of test tube through agarose gel and save DNA strands of the right length

Molecular Computing

 Create single strands by melting

 For each node, select those sequences that anneal to the string of that node

Molecular Computing

 Result: implementation of algorithm in DNA

– First experiment took seven days

– Now possible in seven seconds

Molecular Computing

 Operations: denaturing, annealing, separation, selection, multiplying

 Simulation of Turing Machine is possible

 Problems:

– PCR and separation procedures are error prone

– DNA may form non-existing pseudo-paths

– DNA may form hairpin loops

– Scalability

Molecular Computing

 Combine Evolutionary Computing with

Molecular Computing (EDNA project)

– Use potential errors as feature

– Huge population sizes

– Automation of DNA processing necessary

 Many more techniques from molecular biology can be used

– Plasmids

– Restriction Enzymes

– Fluorescence

Evolutionary Molecular Computing

Gene Assembly in Ciliates

Ciliates

 Very ancient ( ~ 2 . 10 9 years ago)

 Very rich group ( ~ 10000 genetically different organisms)

 Very important from the evolutionary point of view

Ciliates

micronucleus macronucleus

Ciliates

 DNA molecules in micronucleus are very long

(hundreds of kilo bps)

 DNA molecules in macronucleus are genesize, short (average ~ 2000 bps)

Gene Assembly in Ciliates

Gene Assembly in Ciliates

Gene Assembly in Ciliates

 Micronucleus: cell mating

Macronucleus: RNA transcripts (expression)

Micro: I

0

M

1

I

1

M

2

I

2

M

3

… I k

M k

I k+1

 M = P

1

N P

2

 Macro: permutation of (possibly rotated)

M

1

,…, M k and I

0

,…, I k+1 are removed

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Molecular Operators

Gene Assembly

 Pointer structures

 Linked Lists

Natural Computing

 Computing carried on or inspired by (gleaned from) nature

– Evolutionary Computing

– Neural Computing

– Molecular Computing

– Quantum Computing

– Ant Computing

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