Human and social computation
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    Human and social computation Human and social computation Presentation Transcript

    • Putting Humans in the Loop:Human Computation for Natural Resources Management New Developments in IT & Water Amsterdam, Nov 5 2012 Piero Fraternali Politecnico di Milano, Italy piero.fraternali@polimi.it
    • Outline• Human Computation – Origins – Forms • Crowdsourcing • Games with a purpose • Solution space exploration • Social Mobilization • Examples in Natural Resource & Water Management – Open Issues – Research Projects – Conclusions and outlook
    • Human Computation: a definition• According to Von Ahn• Combine humans and computers to solve large-scale problems that neither can solve alone taking advantage of the human cycles• According to Wikipedia:• Human-based computation is a computer science technique in which a computational process performs its function by outsourcing certain steps to humans. This approach uses differences in abilities and alternative costs between humans and computer agents to achieve symbiotic human-computer interaction.
    • Early example: CAPTCHA• Stands for “Completely Automated Public Turing test to tell Computers and Humans Apart”• Luis von Ahn et al. coined the term in 2000• A Program that can tell whether a user is a human or a computer• Humans and machines have complementary skills4
    • The disciplines of HC
    • Forms of HC: crowdsourcing• Crowdsourcing is a distributed model that assigns tasks traditionally undertaken by employees or contractors to an undefined crowd – Split the task into micro-tasks – Assign them to performers in the crowd – Collect partial results into the final one
    • Paid Crowdsourcing: Amazon Mechanical Turk
    • Forms of HC: GWAPS• Games with a Purpose (GWAPs) – Exploiting the billions of hours that people spend online playing with computer games to solve complex problems that involve human intelligence [vA06,LvA09]. – Useful tasks are embedded in a playful experience where human judgment is exploited consciously or unconsciously
    • Types of Games [Luis von Ahn and Laura Dabbish, CACM 2008]Three generic game structures• Output agreement: – Type same output• Input agreement: – Decide if having same input• Inversion problem: – P1 generates output from input – P2 looks at P1-output and guesses P1-input
    • Output Agreement: ESP Game• Players look at common input• Need to agree on output
    • Input Agreement: TagATune• Sometimes difficult to type identical output (e.g., “describe this song”)• Show same or different input, let users describe, ask players if they have same input
    • Inversion Problem: Peekaboom• Non-symmetric players• Input: Image with word• Player 1 slowly reveals pic• Player 2 tries to guess word
    • Sketchness• Puzzle Game, Guess and Draw (Pictionary, iSketch…)• Players take turns drawing the shapes of objects inside an image to make the other players guess the object• Two roles: Sketcher & Guesser• Objectives: Object detection, garment segmentation and tagging
    • Forms of HC: space exploration• Combinatorial problems with intractable solutions spaces, in which humans can help the heuristic core in pruning – Protein folding: Proteins fold from long chains into small balls, each in a very specific shape – Shape is the lower-energy setting, which the most stable – Fold shape is very important to understand interactions with out molecules – Extremely expensive computationally! (too many degrees of freedom)• A Mason-Pfizer monkey virus retroviral protease was modeled by FoldIT gamers in just three weeks
    • Forms of HC: social mobilization• Social Mobilization – Problems with time constraints, where the efficiency of task spreading and of solution finding is essential – An example of the problem and of the techniques employed to face it is the Darpa Network Challenge [PRP+10] – The solution comes from the nature of the reward mechanism and social ties of humans
    • HC & Natural Resource Management• Objectives – Collect and validate data – Extract information from data – Involve people in resource usage planning and management – Change people’s behavior• Approaches – Passive: mine information from existing user’s activity traces – Active: engage people in ad hoc tasks• Ultimate goals – Obtain “better data” for predictive models, planning and management tool: more accurate, at finer time/space resolution, in real time … – Take “better decisions”: more participative, less conflicting, capable of promoting social change
    • Monitoring waterways: CreekWatch• Problem: obtain simple yet useful parameters on water shed conditions in a vast territory at low cost• Solution: geo localized mobile+Web application – Developed at IBM Research Almaden, 4000+ users, 25 countries – The city of San Jose, CA, uses it to prioritize pollution cleanup efforts• Collected data are found to have good quality
    • Predicting population dynamics with twitter data• Problem: obtaining impact of population on territory at high temporal resolution• Can be used to detect events, estimate water consumption bursts, waste production, etc• Solution: using low cost geo-localized data sources (e.g., tweets) together with structured and high cost sources (e.g., mobile phone traces) http://www.streamreasoning.org/demos/london2012
    • Predicting snow level with Flickr images• Problem: predicting the incidence of natural phenomena using user generated content• Solution: using Flickr photos tagged with “snow” to estimate snow fall (precision 100% with 7 snow photos) – H Zhang, M Korayem, DJ Crandall, G LeBuhn: Mining photo-sharing websites to study ecological phenomena. WWW 2012
    • Using social deliberation tools for partipatory planning• Problem: letting a large crowd of citizens propose solutions or deliberate on proposals about public goods• Solution: large scale deliberation and idea management tools – IdeaScale.com, MIT’s Deliberatorium …
    • Open problems• Humans, like machines, can make errors – Cognitive bias, fatigue• Unlike machines humans can cheat – Classification of attacks – Spammer detection• Quality of output improvement techniques are in use • Voting schemes • Workers quality modeling and vote weighing (requires ground truth or machine learning models and iterative / selective labeling of data) • Micro-flows, worker’s pre-task testing • Task to worker assignment, active learning
    • Example of ongoing projects Politecnico di Milano
    • The CrowdSearcher crowd engagement framework
    • Human task design:Tips on workplaces from friends
    • Human task execution with Facebook & Doodle
    • 27 CUbRIK Project• FP7 Integrating Project• Goals: – Advance the architecture of multimedia search – Exploit the human contribution in multimedia search – Use open-source components provided by the community – Start up a search business ecosystem• http://www.cubrikproject.eu/
    • 28Multimedia processing with crowd Detecting logo images in videos
    • 29 Experimental evaluation• Three experimental settings: –No human intervention –Logo validation performed by domain experts –Non-expert crowd on FaceBook• Experiment size –40 people involved –50 task instances generated –70 collected answers
    • 30 Experimental evaluation 1 0.9 0.8 Crowd 0.7 Experts 0.6 ExpertsRecall Experts 0.5 Aleve 0.4 Crowd Chunky 0.3 No Crowd Shout 0.2 Crowd No Crowd 0.1 0 No Crowd 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Precision
    • 31 Experimental evaluation 1 0.9 0.8 Precision decreases Crowd 0.7 Experts 0.6 Reasons for the wrong inclusion ExpertsRecall Experts • Geographical location of the users 0.5 Aleve • Expertise of the involved users 0.4 Crowd Chunky 0.3 No Crowd Shout 0.2 Crowd No Crowd 0.1 0 No Crowd 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Precision
    • 32 Experimental evaluation 1 Precision decreases • Similarity between two 0.9 logos in the data set 0.8 Crowd 0.7 Experts 0.6 ExpertsRecall Experts 0.5 Aleve 0.4 Crowd Chunky 0.3 No Crowd Shout 0.2 Crowd No Crowd 0.1 0 No Crowd 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Precision
    • 33 Future directions & outlook• Find problems where crowd support can be useful, e.g., – Urban water demand prediction: smarter meters are costly and not deployed. Household data can be used to build models• Design crowd interaction – Non only IT: engagement, incentives, ethical and legal issues• Collect and clean-up data• Integrate crowd model and data with (e.g., water) system models• Check validity
    • References• Managing Crowdsourced Human Computation, Panos Ipeirotis, New York University Praveen Paritosh, Google• [LvA09] Edith Law and Luis von Ahn. Input-agreement: a new mechanism for collecting data using human computation games. In Proc. CHI 2009, 2009.• [vA06] Luis von Ahn. Games with a purpose. Computer, 39:92{94, 2006.• [vAMM+08] Luis von Ahn, Ben Maurer, Colin McMillen, David Abraham, and Manuel Blum. recaptcha: Human-based character recognition via web security measures. Science, 321(5895):1465~1468, 2008.[
    • References• Galen Pickard, Iyad Rahwan, Wei Pan, Manuel Cebrian, Riley Crane, Anmol Madan, and Alex Pentland. Time critical social mobilization: The darpa network challenge winning strategy. CoRR, abs/1008.3172, 2010.• Trant J., Exploring the potential for social tagging and folksonomy in art museums: proof of concept. New Rev. Hypermed. Multimed. 12(1), 83–105• Firas Khatib et al, Crystal structure of a monomeric retroviral protease solved by protein folding game players, NATURE, 2011• S. Kim, C. Robson, T. Zimmerman, J. Pierce, and E. M. Haber. Creek watch: pairing usefulness and usability for successful citizen science. In Proceedings of the 29th Int Conf on Human Factors in Computing Systems, pages 2125–2134, New York, NY, 2011.