PhotoSlap:%20A%20Multi-player%20Online%20Game%20for%20Semantic%20Annotation%20%20Proceedings%20of%20the%20Twenty-Second%20Conference%20on%20Artificial%20Intelligence%20(AAAI),%20pp.%201359 - PowerPoint PPT Presentation

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PhotoSlap:%20A%20Multi-player%20Online%20Game%20for%20Semantic%20Annotation%20%20Proceedings%20of%20the%20Twenty-Second%20Conference%20on%20Artificial%20Intelligence%20(AAAI),%20pp.%201359

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PhotoSlap: A Multi-player Online Game for Semantic Annotation Proceedings of the Twenty-Second Conference on Artificial Intelligence (AAAI), pp. 1359 1364 (2007) – PowerPoint PPT presentation

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Title: PhotoSlap:%20A%20Multi-player%20Online%20Game%20for%20Semantic%20Annotation%20%20Proceedings%20of%20the%20Twenty-Second%20Conference%20on%20Artificial%20Intelligence%20(AAAI),%20pp.%201359


1
PhotoSlap A Multi-player Online Game for
Semantic Annotation Proceedings of the
Twenty-Second Conference on ArtificialIntelligenc
e (AAAI), pp. 13591364 (2007)The top
conference in Artificial Intelligence
acceptance rate 27The first intelligent
system demo from Taiwan
  • Chien-Ju Ho(???) ??????, ??????????????
  • Tsung-Hsiang Chang(??? ) ??????, MIT ???
  • Yung-Jen Hsu(???) ???????????,????????

2
Human Computation
3
A Game for Image Clustering
  • Gain the similarity for each pair of image among
    all image database.
  • Use clustering algorithms to group the images.
  • the same person, the same team, the same animal,
    the same location, the same time, the same event

4
Prisoners Dilemma (Game Theorem)
B Stays Silent B Betrays
A Stays Silent A 6 months B 6 months A 10 years B free
A Betrays A free B 10 years A 5 years B 5 years
5
System Overview
6
The First Stage
7
The Second Stage
8
Four Actions for Players (1/2)
  • Flip
  • Each player flips a single card in turn. The
    photos are chosen by the game server adaptively.
  • Slap
  • Given the last two consecutive cards on a central
    pile, players may choose whether to slap.
  • To achieve high scores, a rational player should
    slap as soon as he/she recognizes two consecutive
    photos of the same person.

9
Four Actions for Players (2/2)
  • Object
  • When a player slaps, the other players have the
    option to challenge the slapped result by
    flagging an objection. If the objection is
    successful, the objector would gain points while
    the slapper would lose points.
  • If the objection fails, i.e., falls into the
    trap, the objector is penalized with a large
    point loss.
  • Trap
  • While the object action is used to prevent
    random slapping, the trap mechanism is designed
    to prevent random-objection.
  • At the beginning of a new game, each player is
    presented with a subset of all photos, in which
    he/she can set one or more traps by identifying
    photos containing faces/heads of the same person.

10
Game Theoretic Analysis
For each photo pair in the trap page
For each photo pair in the game page
Player node
Chance node
The player who sets the trap
The player who objects first
The player who slaps first
Payoff of player 1
Payoff of (player 2, player 3)
11
Scoring Rules
  • Consider the subgame in which player 3 is the
    first one to act.
  • Let Ptrap be the probability that the slapped
    pair is a trap.
  • The expected payoff for player 3 to object is
    Ptrap(-Strapped) (1 - Ptrap)Sobject
  • where -Strapped is the penalty for falling into
    the trap
  • and Sobject is the score for successful
    objecting.
  • The expected payoff to stay/object is 0.

12
Subgame Perfect Equilibrium
Trap Slap Object
Match Set Slap Stay
No Match Stay Stay Object
Assuming that all players are rational, striving
to maximize their scores for each game.
13
Social Verification
14
Similarity between Two Images
  • Each pair of images is given a confidence value
    C.
  • C W1(Cs - Co) W2 Ct
  • W1 and W2 are weights
  • Cs, Co, and Ct are the counts of slap, object,
    and trap actions respectively.

15
Evaluation
  • We have conducted small-scale experiments using 4
    focus groups, consisting of 4 users each.
  • For each focus group, users played PhotoSlap for
    a 30-minute session continuously. Each session
    produced about 11 games.
  • The test dataset used in the experiments contains
    572 faces of various poses and illumination from
    24 different persons, and all faces were manually
    labeled and annotated by the authors.
  • Given the test dataset with the ground truths,
    the game is evaluated in the following aspects.

16
Is The Game Fun?
  • At the conclusion of each focus group session,
    the users were requested to answer a set of
    survey questions providing feedbacks about
    playing the game and to write down any specific
    comments.
  • Based on the data collected from the game play
    survey, PhotoSlap received an average score of
    7.6 points on a 10-point scale.
  • All users claimed that they would like to play
    again.

17
How Good Is The Game Strategy? (1/2)
  • To validate the game strategy analysis, precision
    and recall are measured.
  • In addition to three player actions (slap,
    object, and trap), we define and analyze an extra
    action called slap-object which means slapping
    without any objection.
  • Let S1action be the set of photo pairs applied
    with the action.
  • Let S2action be the set of photo pairs that
    should be applied with the action according to
    the target strategy.

18
How Good Is The Game Strategy? (2/2)
19
Is The Game Productive?
  • By combining the results of the actions being
    taken, the links between face photos will be
    built and the face clusters can thus be formed.
  • Therefore, the productivity of the game is
    measured by the links being built and the
    percentage of the correct links.
  • In the focus-group study (8 person-hours), 1480
    links are formed in which 1455 links are correct.
  • In other words, each game can produce 12.3 links
    per minute and 98.31 of them are correct.

20
PhotoSlap System
21
Human Computation(Game for purpose)
  • Human as the algorithm
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