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J.C.D. Scharpff

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A serious gaming experiment on road maintenance planning

Journal article (2020) - Joris Scharpff, Daan Schraven, Leentje Volker, Matthijs T.J. Spaan, Mathijs M. de Weerdt
The next step in the use of innovative, dynamic and performance-based contracts for service delivery by contractors could be use of monetary incentives to stimulate self-regulation of the network. Because it is currently unclear how performance-based payments in network tenders can effectively encourage network members to coordinate their own operations, a serious game was performed that simulates road maintenance planning to study changes in decision making and the emergence of network coordination. The experiments show that monetary incentives influence decision making, but their effect may be opposite to their intended aim and can lead to a competitive network. It was, however, also found that this competitiveness is not shown in networks where members are familiar with each other. This leads to the conclusion that penalty-based incentive mechanisms probably interfere with self-regulation and that the social dimension of contractor collaboration is paramount to the success of network-based contracting of construction activities. ...

Mechanisms and Algorithms for Self-regulation in Decision-Theoretic Planning

Doctoral thesis (2020) - J.C.D. Scharpff
This thesis explores the potential of self-regulation in collective decision making to align interests and optimise joint performance. Demonstrated in the domain of road maintenance planning, this research contributes novel incentive mechanisms and algorithmic techniques to incite self-regulation and coordinate agent interactions, paired with a practical validation of the concept through serious gaming. The learnings of this work guide the design and implementation of future performance-based partnerships and advance the current state-of-the-art in sequential decision making. ...

Game design and first results

This white paper describes the Road Maintenance Planning game, a game that simulates planning, coordination and execution of maintenance projects in the domain of infrastructural maintenance. In particular, the game models the dynamic contracting procedure of Volker et al. (2014), an innovative way of contracting public works to a team group of service providers. Foremost, this paper describes the game design, its practical set-up and the methodology for collecting data from gaming sessions so that future researchers can make use of the game. Additionally, this white paper includes a complete overview of the first empirical results obtained from 7 gaming sessions as part of the research in (Scharpff et al. 2019). The source code and design documents can be found on GitLab and may be used for academic purposes only. ...
Conference paper (2016) - Joris Scharpff, Diederik M. Roijers, Frans A. Oliehoek, Matthijs T. J. Spaan, M.M. de Weerdt
In cooperative multi-agent sequential decision making under uncertainty, agents must coordinate to find an optimal joint policy that maximises joint value. Typical algorithms exploit additive structure in the value function, but in the fully-observable multi-agent MDP (MMDP) setting such structure is not present. We propose a new optimal solver for transition-independent MMDPs, in which agents can only affect their own state but their reward depends on joint transitions. We represent these de- pendencies compactly in conditional return graphs (CRGs). Using CRGs the value of a joint policy and the bounds on partially specified joint policies can be efficiently computed. We propose CoRe, a novel branch-and-bound policy search algorithm building on CRGs. CoRe typically requires less runtime than the available alternatives and finds solutions to previously unsolvable problems. ...
Conference paper (2014) - Diederik M. Roijers, Joris Scharpff, Matthijs T.J. Spaan, Frans A. Oliehoek, Mathijs M. De Weerdt, Shimon Whiteson
Planning under uncertainty poses a complex problem in which multiple objectives often need to be balanced. When dealing with multiple objectives, it is often assumed that the relative importance of the objectives is known a priori. However, in practice human decision makers often find it hard to specify such preferences exactly, and would prefer a decision support system that presents a range of possible alternatives. We propose two algorithms for computing these alternatives for the case of linearly weighted objectives. First, we propose an anytime method, approximate optimistic linear support (AOLS), that incrementally builds up a complete set of -optimal plans, exploiting the piecewise-linear and convex shape of the value function. Second, we propose an approximate anytime method, scalarised sample incremental improvement (SSII), that employs weight sampling to focus on the most interesting regions in weight space, as suggested by a prior over preferences. We show empirically that our methods are able to produce (near-)optimal alternative sets orders of magnitude faster than existing techniques, thereby demonstrating that our methods provide sensible approximations in stochastic multi-objective domains. ...
Scheduling of infrastructural maintenance poses a complex multi-agent problem. Commonly a central authority is responsible for the quality and throughput of the infrastructure, while the actual maintenance is performed by multiple self-interested contractors. Not only does the central authority have to (economically) incentivise agents to consider quality and throughput, it is also burdened with the coordination of agents' activities on the network with contingent activity durations. We introduce a coordination method that combines planning under uncertainty and dynamic mechanism design to coordinate agents on a network level. We apply this method on maintenance planning scenarios obtained through accurate modelling of the problem domain. To the best of our knowledge, this is the first application of dynamic mechanism design on a real-world problem. Finally, we validate the feasibility of our method through experimental evaluation and identify current open challenges for both the planning and scheduling as well as the mechanism design communities. ...