von neumann’s automaton and viruses
DESCRIPTION
Von Neumann’s Automaton and Viruses. Most slides taken from Weizmann Institute of Science and Rensselaer Polytechnic Institute. The General Question. What kind of logical organization is sufficient for an automaton to control itself in such a manner that it reproduces itself?. - PowerPoint PPT PresentationTRANSCRIPT
Von Neumann’s Von Neumann’s Automaton and Automaton and
VirusesVirusesMost slides taken fromWeizmann Institute of Science andRensselaer Polytechnic Institute
The General Question
What kind of logical organization is sufficient for an automaton to control
itself in such a manner that it reproduces itself?
Von Neumann Neighborhood
2
3 1 5
4
State of the cell at time t+1is calculable from its state and its
four non-diagonal neighboring cellsat time t.
States in Von Neumann Automaton
• Each cell is capable of 29 different states.• Each state is excited or unexcited.• Movement of data on the cellular lattice is determined
by the changes of unexcited and excited states in cell. • Cells change at discrete times according to the
transition rule.
000 000
000 000
0 0000 0
unexcited unexcited unexcited unexcited unexcited unexcited
0 0signal 001 0
t
excited unexcited unexcited unexcited unexcited unexcited
000 0
t+1
10
unexcited excited unexcited unexcited unexcited unexcited
000 0
t+2
10
unexcited excited unexcited unexcited unexcited unexcited
000 0
t+3
10
unexcited unexcited excited unexcited unexcited unexcitedunexcited unexcited unexcited excited unexcited unexcited
000 0
t+4
0 1
unexcited unexcited unexcited unexcited excited unexcited
100 0
t+5
0 0
unexcited unexcited unexcited unexcited unexcited excited
000 1
t+6
0 0 000 0
t+7
0 0 1
unexcited unexcited unexcited unexcited unexcited unexcited
000 0
t+8
0 0 0
unexcited unexcited unexcited unexcited unexcited unexcited
Ordinary Transmission States
4 unexcited states 4 excited states
signal
Quiescent State
Cells in the quiescent state U have to be excited with more
than one signal directed to them.
signal
cell in the
quiescent state cell in the ordinary
transmission state
Confluent States
C 0 0u n e xc ite d s ta te
C 0 1e xc ite d s ta te
C 1 0e x c i te d s ta te
C 1 1e xc ite d s ta te
C X YX sp e c i fy in g th e cu r re n t s ta te
Y th e n e x t s ta te
C000
1C00
C01
C100
1
C11
C000
1
C01
C100
1
C11
C10 and C01
C00
t C10
t+2
C01
t+1 C00
t+3
Cell in confluent state directs signal to theneighboring cells not pointing to it.
C000
1C00
C01
C100
1
C11
C000
1
C01
C100
1
C11
C00
t
C00
C00
t+1 C00
t+2 C00
t+3
All of the cells in ordinary transmission states pointing to cell in confluent state have to be
excited.
A not excited cell at the input of a confluent cell
C11
C01
t
C01
t C11
t+1 C10
t+2 C00
t+3Two dots inside
The number of dots in = the number of dots out
C000
1C00
C01
C100
1
C11
C000
1
C01
C100
1
C11
Pulser
A pulser P(i1, i2 ,…, in) is used to encode a sequence of signals so that a single excited signal
entering the input cell will produce the sequence i1, i2 ,…, in at the output cell.
input
output
at time t
at time t+ through t+ +n
C
Pulser(10101)
C
C C
t+5
excited signal 01
tt+1
10
t+2t+4
10
t+3
01
t+6
01
t+7
01
10
t+8
10
t+14
1
t+12
1
t+10
1
t+11
0
t+13
0
t+9
Decoder(1x1x1)A decoder produces a single signal if the sequence
it receives has signals in specified positions.
C C C
C C C 01
texcited signal 10
t+1excited signal
t+201
t+310 01excited signal
t+41001
t+50110
t+610 01
01
t+701 10
10
t+801
01
10
t+910
1001
t+1001
t+1110
10 01
t+12
10
t+13
01
t+14
10
t+15t+16
01
t+17
10
t+18
1
t+19
Repeater
C signal 01 10 1 10 01 1
Repeater repeats the sequence of signals untilit is turned off.
destruction processconstruction process
Special Transmission States
4 unexcited states 4 excited states
They are similar in operation to ordinarytransmission states, but they convertconfluent states to quiescent state.
Special transmission states are denoted by double arrow notation
The Destruction ProcessThe destruction process transforms unexcitedand excited states into the quiescent state in
single step.
C10
t t+1
Sensitive States
S 0 S 0 S 1 S 0 0 S 0 1 S 1 1 S 0 0 0
S
They are intermediary states converting quiescent state into one of the 9 unexcited states
C00
The Sensitized Tree
S0
10
10
1 S11
01
0
1
U S0
S1
S10
C00
01
S00
S0110
S0000
0
1
1
U S0
S1
S10
quiescent state
The Construction Process
t
S10
t+3
S100
t+4
t+5
S0
t+1
t+2
S1
t
S10
t+3
S100
t+4 t+5
S0
t+1 t+2
S1
S0
10
10
1 S11
01
0
1
U S0
S1
S10
C00
01
S00S0
110
S0000
0
1
1
U S0
S1
S10
quiescent state
Periodic Pulser
P(11111)
RepeaterP(10101)
C
C
C
C
C C C C C C
C
C
C
C
C
C
C
C
C
C
C
C
C
C C
C
C
C
C C
C 1
C
C 0
C
C 1
C
C
S0
C
S1S11S111
C
C signal
signal
Coded Channel
D=decoder
P=pulser
Transition And Output Table
Automaton
o0=s0, etc
Finite Automaton
Constructing Arm
Horizontal Advance
Horizontal Advance of Constructing Arm
Vertical Advance of Constructing Arm
Horizontal Retreat of Constructing Arm
Vertical Retreat of Constructing Arm
Injection of Starting Stimulus
Reading Loop
Constructing Arm
Universal Computer
Universal Constructor
Automata Self-reproduction
Automata Self-reproduction
Automata Self-reproduction
Cellular Automata vs Viruses
Cellular Artificial Life
Virus: Definition• A simple computer program that attaches
itself to a legitimate executable program, and reproduces itself when the program is run.
• Trojan Horse: no self-replication• Worm: infects through security hole, then self-
replicates through idle memory
Virus Types• Boot sector viruses
– Infects boot sector on diskette– Replaces it with replicated copy of virus– Hides in memory, infects all new disks
• Executable Viruses– Resident, direct action or a combination– Resident remains in memory and attacks every
program run– Direct action may search for a new file to infect
Virus Categories• Parasitic: spread on program execution
through storage and transmission medium• Multipartite: infects both boot sector and
executables• Stealth: hidden in memory to infect or redirect
interrupts• Polymorphic: uses encryption to change
signature for each replica• Dropper: places boot sector infector on disk
Computer vs. Biology• String of genetic material vs. instruction set• Neither capable of self-replication outside of a
host• Takes over cell and uses it to spread virus• Unexpected and uncontrollable replication
makes viruses (of either type) dangerous
Virus vs. Alife• Patterns in space-time• Self reproduction• Information storage of self representation• Metabolism• Functional interaction with environment• Interdependence of parts• Stability under perturbations• Growth• Evolution < major flaw in theory
References• J. Beuchat, J. Haenni, Von Neumann’s 29-State
Cellular Automaton: A Hardware Implementation, IEEE Transactions On Education, Vol. 43, No. 3, 2000.
• A.W.Burks, Von Neumann Self-Reproducing Automata, Essay 1 from Essays on Cellular Automata.
• J.Signorini, How a SIMD machine can implement a complex cellular automaton? A case study: von Neumann’s 29-state cellular automaton, IEEE Proc. Supercomput.,1989.