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Introduction	to	AI
9th Lecture
1990‐2010:	The	Successes	of	AI
Wouter	Beek
me@wouterbeek.com
18	November	2010
Modern	Approaches	and	
Techniques
Hybrid	Architectures
0 Hybrid Architectures:	combining	the	various	agent	
architectures.
0 E.g.	combining	reflex	components	with	knowledge‐
based	components.
0 Compilation:	convert	declarative	information	at	the	
deliberate	level	into	more	efficient	representations,	
eventually	reaching	the	reflex	level.
0 Soar	(1987),	Theo	(1990).
0 Solutions	to	new	problems	are	derived	by	deliberation,	
but	are	compiled	and	stored	at	the	reflex	level	for	
solving	future	occurrences	of	similar	problems.
Real‐Time	AI
0 Increasingly	more	complex	environments:	partially	
observable,	multiagent,	stochastic,	sequential,	
dynamic	and/or	semidynamic,	continuous,	unknown.
0 Satisficing:	deliberating	long	enough	to	come	up	with	
an	answer	that	is good	enough.
0 ‘Good’	is	context‐dependent,	i.e.	with	respect	to	a	
purpose.
0 Anytime	Algorithms:	there	is	always an	output,	
which	becomes	better	over	time.
0 Bounded	rationality:	forms	of	rational	behavior	that	
adhere	to	the	constraints	of	satisficing.
0 Bounded	optimality:	the	best	algorithm	given	the	
computational	resource	constraints.
Meta‐Cognition
0 Decision‐Theoretic	Metareasoning:	deciding	which	
computations	to	perform	(in	what	order)	and	which	not.
0 Computations	are	characterized	by	costs	and	benefits:
0 Cost:	time,	memory,	and	knowledge	input	needed.
0 Benefit:	the	projected	quality	improvement	of	the	system’s	
behavior	due	to	the	computation.
0 Computation	ordering:	an	earlier	computation’s	benefit	
may	be	the	knowledge	input	to	later	computations.
0 Reflective	Architecture:	combining	environment state	
and	computation	state.	An	agents’	reasoning	process	
becomes	part	of	the	environment	(what	is	observed).
Multiagent	Systems
0 Cooperation
0 Competition
0 Swarm	intelligence:	performance	measure	applied	
to	collective	behavior.
0 Decentralized	representation
0 Emergent	behavior
0 Weak	emergence:	the	qualities	of	the	system	are	
reducible	to	the	system's	constituent	parts.
0 Strong	emergence:	e.g.	qualia.
0 The	concepts	of	utility	and	rationality	change!
0 What	is	rational	for	the	swarm	is	not the	sum	of	what	is	
rational	for	all	individuals.
Prisoner’s	dilemma
Prisoner	B	silent Prisoner	B	betray
Prisoner A	silent A:1 day,	B: 1	day A:10	year,	B:0
Prisoner A	betray A:0,	B:10	years A:9	years,	B:9	years
Two	suspects	are	arrested.	If	one	testifies	against	the	other	(betray)	and	
the	other	remains	silent,	the	betrayer	goes	free	and	the	silent	accomplice	
receives	the	full	10‐year	sentence.	If	both	remain	silent,	both	prisoners	
are	sentenced	to	only	1	day	for	not	cooperating	with	the	investigation.	If	
each	betrays	 the	other,	each	receives	a	9‐year	sentence.	How	should	the	
prisoners	act?
• No	matter	what	the	other	player	does,	a player	will	always
gain	a	greater	payoff	by	playing	betray.
• Since	in	any situation	betraying	is	more	beneficial	than	
remaining	silent,	all rational	players	will	betray.
Modern	Systems	and	
Results
Autonomous	Driver
0 DARPA	Grand	Challenge:	competition	for	long	
distance,	driverless	vehicles.
0 Goal:	making	1/3	of	the	military	ground	units	
autonomous.
0 2005,	STANLEY:	driverless	robotic	car	wins	the	
DARPA	Grand	Challenge,	212km	off‐road	course.
0 2006,	BOSS:	driverless	robotic	car	in	urban	area.
Autonomous	Planning
0 2000,	RemoteAgent:	on‐board	autonomous	planning,	
scheduling	operations	for	spacecraft.	NASA.
0 2004,	MAPGEN:	NASA’s	Mars	Exploration	Rovers.
0 2008,	MEXAR2,	European	Space	Agency’s	Mars	
Express.
Computational	Linguistics
0 Speech	recognition	and	dialogue	handling	in	call	
centers
0 Automatic	Translation
0 Hands‐free	computing
0 Speech‐to‐text
0 Speaker	identification
0 AI’s	main	interest	in	the	1960’s.
Games
Chess
0 1997,	Deep	Blue	(IBM):	the	first	computer	to	beat	the	
world	champion	in	chess,	3.5‐2.5.
0 “The	brain’s	last	stand.”	[Newsweek]
0 IBM’s	stock	increased	by	$18.000.000.000.
0 2004,	Hydra defeats	world	champion	Ponomariov 2‐0.
0 Elo rating	2850‐3000,	higher	than	that	of	any	human.
0 2007,	Rybka defeats	several	grand	masters,	even	
when	giving	them	certain	advantages.
Checkers: 1994,	Chinook becomes	the	world	champion.
Go: MoGo,	still	performs	at	advanced	amateur	level.
0 There	is	still	work	to	do	on	some	games.
Automatic	Classification
0 Pattern	recognition
0 Discovering	complicated	interactions:	e.g.	drug	use,	
medical	imaging.
0 OCR
0 Handwriting	recognition
0 Biometric	identification
0 Credit	card	usage
0 Document	classification
0 Classifying	1.000.000.000	spam	messages	every	day.
0 Search
Logistics	planning
0 1991,	DART (Dynamic	Analysis	and	Replanning Tool)	
scheduled	transportation	during	the	Persian	Gulf	
crisis.
0 Starting	points,	destinations,	routes,	conflict	resolution.
0 Over	50.000	vehicles,	cargo,	people.
0 According	to	DARPA,	this	system	alone	paid	back	30	
years	of	investment	in	AI.
Robotics
Toys:
0 ASIMO
0 1997‐present,	RoboCup
0 TOPIO,	table	tennis
Practical	applications:
0 Industrial	Robotics
0 2.000.000	Roombas sold	by	iRobot	corporation!
0 Robotic	vacuum	cleaners…
Neurological	Simulation
0 Blue	Brain	Project:	A	neurologically	realistic	model	
of	neurons.
0 Blue	Gene	supercomputer
0 NEURON	software
0 2007,	simulating	a	rat’s	neocortical	column	
(functional	part	of	the	neocortex).
0 2009,	director	Henry	Markram announced	to	build	a	
human	brain	in	10	years	time.
0 Think	of	what	you	learned	about	the	history	of	AI.	What	
is	wrong	with	Markram’s announcement?
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