Of 27 01/06/2015CMI: Uncertain Communication1 Communication Amid Uncertainty Madhu Sudan Microsoft...
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Of 27 01/06/2015CMI: Uncertain Communication1 Communication Amid Uncertainty Madhu Sudan Microsoft Research Based on Juba, S. (STOC 2008, ITCS 2011) Juba,
of 27 01/06/2015CMI: Uncertain Communication1 Communication
Amid Uncertainty Madhu Sudan Microsoft Research Based on Juba, S.
(STOC 2008, ITCS 2011) Juba, S. (STOC 2008, ITCS 2011) Goldreich,
Juba, S. (JACM 2011) Goldreich, Juba, S. (JACM 2011) Juba, Kalai,
Khanna, S. (ITCS 2011) Juba, Kalai, Khanna, S. (ITCS 2011)
Haramaty, S. (ITCS 2014) Haramaty, S. (ITCS 2014) Canonne,
Guruswami, Meka, S. (ITCS 2015) Canonne, Guruswami, Meka, S. (ITCS
2015) Leshno, S. (manuscript) Leshno, S. (manuscript)
Slide 2
of 27 01/06/2015CMI: Uncertain Communication2 Congratulations,
CMI! Bravo!!!
Slide 3
of 27 Communication vs. Computation Communication vs.
Computation Interdependent technologies: Neither can exist without
other Interdependent technologies: Neither can exist without other
Technologies/Products/Commerce developed (mostly) independently.
Technologies/Products/Commerce developed (mostly) independently.
Early products based on clean abstractions of the other. Early
products based on clean abstractions of the other. Later versions
added other capability as afterthought. Later versions added other
capability as afterthought. Today products deeply integrated. Today
products deeply integrated. Deep theories: Deep theories:
01/06/2015CMI: Uncertain Communication3 Well separated and have
stayed that way Turing 36 Shannon 48
Slide 4
of 27 Consequences of the wall 01/06/2015CMI: Uncertain
Communication4
Slide 5
of 27 Sample problems: Universal printing: Universal printing:
You are visiting a friend. You can use their Wifi network, but not
their printer. Why? You are visiting a friend. You can use their
Wifi network, but not their printer. Why? Projecting from your
laptop: Projecting from your laptop: Machines that learn to
communicate, and learn to understand each other. Machines that
learn to communicate, and learn to understand each other. Digital
libraries: Digital libraries: Data that lives forever
(communication across time), while devices change. Data that lives
forever (communication across time), while devices change.
01/06/2015CMI: Uncertain Communication5
Slide 6
of 27 Essence of semantics: Uncertainty Shannon: Shannon: The
significant aspect is that the actual message is one selected from
a set of possible messages The significant aspect is that the
actual message is one selected from a set of possible messages
Essence of unreliability today: Essence of unreliability today:
Context: Determines set of possible messages. Context: Determines
set of possible messages. dictionary, grammar, general knowledge
dictionary, grammar, general knowledge coding scheme, prior
distribution, communication protocols coding scheme, prior
distribution, communication protocols Context is HUGE; and not
shared perfectly; Context is HUGE; and not shared perfectly;
01/06/2015CMI: Uncertain Communication6
Slide 7
of 27 Modelling uncertainty Classical Shannon Model
01/06/2015CMI: Uncertain Communication7 A B Channel B2B2B2B2
AkAkAkAk A3A3A3A3 A2A2A2A2 A1A1A1A1 B1B1B1B1 B3B3B3B3 BjBjBjBj
Uncertain Communication Model New Class of Problems New challenges
Needs more attention!
Slide 8
of 27 Hope Better understanding of existing mechanisms Better
understanding of existing mechanisms In natural communication In
natural communication In ad-hoc designs In ad-hoc designs What
problems are they solving? What problems are they solving? Better
solutions? Better solutions? Or at least understand how to measure
the quality of a solution. Or at least understand how to measure
the quality of a solution. 01/06/2015CMI: Uncertain
Communication8
Slide 9
of 27 01/06/2015CMI: Uncertain Communication9 II: Uncertain
Compression
Slide 10
of 27 Human-Human Communication 01/06/2015CMI: Uncertain
Communication10 Prob. distribution on messages
Slide 11
of 27 Human Communication - 2 01/06/2015CMI: Uncertain
Communication11ReceivercontextSendercontext
Slide 12
of 27 Implications 01/06/2015CMI: Uncertain
Communication12
Slide 13
of 27 01/06/2015CMI: Uncertain Communication13 III: Imperfectly
Shared Randomness
Slide 14
of 27 Communication (Complexity) 01/06/2015CMI: Uncertain
Communication14 AliceAlice BobBob CompressDecompress In general,
model allows interaction. For this talk, only one way comm.
Slide 15
of 27 Brief history 01/06/2015CMI: Uncertain
Communication15
Slide 16
of 27 Results 01/06/2015CMI: Uncertain Communication16
Slide 17
of 27 Some General Lessons Compression Protocol: Compression
Protocol: Adds error-correction to [JKKS] protocol. Adds
error-correction to [JKKS] protocol. Send shortest word that is far
from words of other high probability messages. Send shortest word
that is far from words of other high probability messages. Another
natural protocol. Another natural protocol. General Protocol:
General Protocol: Much more statistical Much more statistical
Classical protocol for Equality: Classical protocol for Equality:
Alice sends random coordinate of ECC(x) Alice sends random
coordinate of ECC(x) New Protocol New Protocol ~ Alice send # 1s in
random subset of coordinates. ~ Alice send # 1s in random subset of
coordinates. 01/06/2015CMI: Uncertain Communication17
Slide 18
of 27 01/06/2015CMI: Uncertain Communication18 IV:
Coordination
Slide 19
of 27 Communicate meaning? 01/06/2015CMI: Uncertain
Communication19
Slide 20
of 27 (Mis) Understanding? Uncertainty problem: Uncertainty
problem: Sender/receiver disagree on meaning of bits
Sender/receiver disagree on meaning of bits Definition of
Understanding? Definition of Understanding? Sender sends
instructions; Receiver follows? Sender sends instructions; Receiver
follows? Errors undetectable (by receiver) Errors undetectable (by
receiver) Not the right definition anyway: Not the right definition
anyway: Does receiver want to follow instructions Does receiver
want to follow instructions What does receiver gain by following
instructions? Must have its own Goal/Incentives. What does receiver
gain by following instructions? Must have its own Goal/Incentives.
[ Goldreich,Juba,S. 2012 ]: Goal-oriented communication: [
Goldreich,Juba,S. 2012 ]: Goal-oriented communication:
01/06/2015CMI: Uncertain
Communication20ReceiverdictionarySenderdictionary
Slide 21
of 27 (Mis) Understanding? Uncertainty problem: Uncertainty
problem: Sender/receiver disagree on meaning of bits
Sender/receiver disagree on meaning of bits Definition of
Understanding? Definition of Understanding? Receiver has
goals/incentives. Receiver has goals/incentives. [
Goldreich,Juba,S. 2012 ]: Goal-oriented communication: [
Goldreich,Juba,S. 2012 ]: Goal-oriented communication: Define
general communication problems (and goals) Define general
communication problems (and goals) Show that if Show that if Sender
can help receiver achieve goal (from any state) Sender can help
receiver achieve goal (from any state) Receiver can sense progress
towards goal Receiver can sense progress towards goal then then
Receiver can achieve goal. Receiver can achieve goal. Functional
definition of understanding. Functional definition of
understanding. 01/06/2015CMI: Uncertain
Communication21ReceiverdictionarySenderdictionary
Slide 22
of 27 Illustration: (Repeated) Coordination 01/06/2015CMI:
Uncertain Communication22
Slide 23
of 27 Our setting 01/06/2015CMI: Uncertain Communication23
Slide 24
of 27 Coordination with Uncertainty 01/06/2015CMI: Uncertain
Communication24
Slide 25
of 27 Lessons Coordination is possible: Coordination is
possible: Even in extreme settings where Even in extreme settings
where Alice has almost no idea of Bob Alice has almost no idea of
Bob Bob has almost no idea of Alice Bob has almost no idea of Alice
Alice is trying to learn Bob Alice is trying to learn Bob Bob is
trying to learn Alice Bob is trying to learn Alice Learning is slow
Learning is slow Need to incorporate beliefs to measure efficiency.
[Juba, S. 2011] Need to incorporate beliefs to measure efficiency.
[Juba, S. 2011] Does process become more efficient when languages
have structure? [Open] Does process become more efficient when
languages have structure? [Open] 01/06/2015CMI: Uncertain
Communication25
Slide 26
of 27 Conclusions 01/06/2015CMI: Uncertain Communication26
Slide 27
of 27 Thank You! 01/06/2015CMI: Uncertain Communication27