Task assignment optimization in knowledge-intensive crowdsourcing

Abstract

We present SmartCrowd, a framework for optimizing task assignment in knowledge-intensive crowdsourcing (KI-C). SmartCrowd distinguishes itself by formulating, for the first time, the problem of worker-to-task assignment in KI-C as an optimization problem, by proposing efficient adaptive algorithms to solve it and by accounting for human factors, such as worker expertise, wage requirements, and availability inside the optimization process. We present rigorous theoretical analyses of the task assignment optimization problem and propose optimal and approximation algorithms with guarantees, which rely on index pre-computation and adaptive maintenance. We perform extensive performance and quality experiments using real and synthetic data to demonstrate that the SmartCrowd approach is necessary to achieve efficient task assignments of high-quality under guaranteed cost budget.

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Notes

  1. 1.

    With the availability of historical information, worker profiles (knowledge skills and expected wage) can be learned by the platform. Profile learning is an independent research problem in its own merit, orthogonal to this work.

  2. 2.

    Acceptance ratio of a worker is the probability that she accepts a recommended task.

  3. 3.

    Non-preemption ensures that a worker cannot be interrupted after she is assigned to a task.

  4. 4.

    \(Q_{t_j}\) is the threshold for skill \(j\) and \(q_{t_j} \ge Q_{t_j}\).

  5. 5.

    \(Q_{t_j}\) is the threshold for skill \(j\) and \(q_{t_j} \ge Q_{t_j}\).

  6. 6.

    If none of the workers in \({\mathcal {A'}}\) contributed to \(t\), then \(v'_t=v_t\).

  7. 7.

    Amazon Mechanical Turk, www.mturk.com.

  8. 8.

    https://www.odesk.com/.

  9. 9.

    http://en.wikipedia.org/wiki/Fansub.

  10. 10.

    https://www.odesk.com/

  11. 11.

    https://www.quirky.com/.

  12. 12.

    http://openideo.com/.

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Correspondence to Senjuti Basu Roy.

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The work of Saravanan Thirumuruganathan and Gautam Das is partially supported by NSF Grants 0812601, 0915834, 1018865, a NHARP grant from the Texas Higher Education Coordinating Board, and grants from Microsoft Research and Nokia Research.

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Basu Roy, S., Lykourentzou, I., Thirumuruganathan, S. et al. Task assignment optimization in knowledge-intensive crowdsourcing. The VLDB Journal 24, 467–491 (2015). https://doi.org/10.1007/s00778-015-0385-2

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Keywords

  • Collaborative crowdsourcing
  • Optimization
  • Knowledge-intensive crowdsourcing
  • Human factors