Planning to Control Crowd-Sourced Workflows Daniel S. Weld - - PDF document

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Planning to Control Crowd-Sourced Workflows Daniel S. Weld - - PDF document

3/4/20 Planning to Control Crowd-Sourced Workflows Daniel S. Weld University of Washington 1 30,000 View Crowdsourcing is huge & growing rapidly Virtual organizations Flash teams with mixed human & machine members


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Planning to Control Crowd-Sourced Workflows

Daniel S. Weld University of Washington

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30,000’ View

  • Crowdsourcing is huge & growing rapidly

– Virtual organizations – Flash teams with mixed human & machine members

  • Automatic organization of work

– Reduce labor required by 30-85%

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  • Performing work by soliciting effort from many people
  • Combining the efforts of volunteers/part-time workers

(each contributing a small portion) to produce a large or significant result

Crowdsourcing

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Crowdsourcing Successes

Universal reference for anything Answers to 7.1 M prog. questions 190 M reviews of 4.4 M businesses

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Citizen Science

Game to find 3D structure of proteins. Solved 15 year outstanding AIDS puzzle 800,000 volunteers – Hubble images Discovered “Hanny’s Voorwerp” black-hole “Pea galaxies” Crowdsourced bird count & identification Migration shift -> effect of climate change

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Labor Marketplaces

Will Grow to $5B by 2018 [Staffing Industry Analysts]

  • 2.7 million workers
  • 540,000 requestors
  • 35M hours worked in 2012

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Charts from Panos Ipierotis’ blog; phone from pixabay

. Nationality and gender of

60% Growth Hours / week Nationality

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Example Job on Mechanical Turk

Write a descriptive caption for this picture, then submit.

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Submit $0.05

Figure from [Little et al. 2010]

A parial view of a pocket calculator together with some coins and a pen.

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  • Challenges

– Small work units – Reliability & skill of individual workers vary

  • Therefore

– Use a workflow to aggregate results & ensure quality – Manage workers with (unreliable) workers

Big Work from Micro-Contributions

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Ex: Iterative Improvement

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initial caption

[Little et al, 2010]

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Ex: Iterative Improvement

initial caption

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[Little et al, 2010]

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Ex: Iterative Improvement

initial caption

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[Little et al, 2010]

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[Little et al, 2010]

Ex: Iterative Improvement

initial caption

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After 8 iterations

A CASIO multi-function, solar powered scientific calculator. A blue ball point pen with a blue rubber grip and the tip extended. Six British coins; two of £1 value, three of 20p value and one of 1p value. Seems to be a theme illustration for a brochure or document cover treating finance - probably personal finance.

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First version

A parial view of a pocket calculator together with some coins and a pen.

Iterative Improvement

[Little et al, 2010]

Figure from [Little et al. 2010]

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[Little et al, 2010]

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[Little et al, 2010]

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Workflow Control Problem

How many times? How many voters? Adaptive, Decision-Theoretic Control

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TurKontrol

POMDP Control of Iterative Improvement Peng Dai Chris Lin Both co-advised with Mausam

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Artificial Intelligence 101

Agent Sensors ? Actuators Environment

Percepts Actions

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POMDP

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Partially-Observable Markov Decision Process

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Figure from Dan Klein & Pieter Abbeel - UC Berkeley CS188: http://ai.berkeley.edu.] And Sarah Reeves (http://dear-theophilus.deviantart.com/)

World State s = <x, y> Actions P(s’ | s, a) Cost c Observe: Next State s’ = <x’, y’> Reward = f(s, a, s’) Input: Output: While learning action & reward probabilities (Reinforcement learning) Construct policy, π : SàA, that chooses best action for each state I.e., actions that maximize expected reward – costs over time

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Partially-Observable Markov Decision Process

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Belief State P(s) Actions P(s’ | s, a) Cost c Observe: Noisy Sensor = f(s’) Input: Output: While learning action & reward probabilities (Reinforcement learning) Construct policy, π : SàA, that chooses best action for each state I.e., actions that maximize expected reward – costs over time Reward

Figure from Dan Klein & Pieter Abbeel - UC Berkeley CS188: http://ai.berkeley.edu.]

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Solving the POMDP

Constructing the policy, π, to choose the best action

  • Many algorithms

– Point-based methods – UCT on discretized space – Lookahead search with beta distribution belief states

  • Exploration / exploitation problem

–ε-greedy

– UCB / Multi-armed bandit

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Q*(s, a) = Σs’ P(s’ | s, a) [ R(s, a, s’) + γ Maxa Q*(s, a) ]

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From

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Robot figure from Dan Klein & Pieter Abbeel - UC Berkeley CS188: http://ai.berkeley.edu.]

(Hidden) World State Actions Costs Reward

To

Quality Q1, Q2 ∈(0,1) Improve caption task Vote best caption $$ paid to workers F(quality returned) <x,y> coords Move Grasp Power used

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Transition Model of Improve Action

Qualitya1 Quality a2 Worker creates (hopefully) improved artifact

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P P

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Belief State

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Qualitya1 Quality a2 P P

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Transition Model of Voting Action

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Qualitya1 Quality a2 P P Qualitya1 Quality a2 P P

Learned using Expectation Maximization

Worker votes that artifact 1 is better

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POMDP for Iterative Improvement

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need improving ? make ballot job update quality estimates submit Y N Y N better of α and α’ initial artifact (α) estimate quality

  • f

α’

more voting ?

α α’ α’

α

generate improve job

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α’

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α’

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

46

POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

47

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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POMDP for Iterative Improvement

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need improving ? generate improve job make ballot job update quality estimates submit α Y N Y N initial artifact ( ) estimate quality

  • f

α’

more voting ?

α α’ α'

better of α and α’

α

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Comparison

40 images, same average cost

0.5 0.55 0.6 0.65 0.7 0.75 0.8

POMDP Hand Coded Quality

Controlling quality: POMDP 30% less labor

[Dai, Mausam & W, AAAI-11] [Dai et al. AIJ 2013]

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Allocation of Human Labor

POMDP (TurKontrol) Hand Coded

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Human Labor Redirected

POMDP Hand Coded

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Extra Slides

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