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We study the strategical behaviour of firms facing a lot-sizing problem with Cournot competition. Each player is a firm with her own production facility, modeled as an uncapacitated lot-sizing problem (Le., production incurs set-up and variable costs and inventories are allowed). A Cournot competition is played in each time period (market) with each player deciding the quantity of product to place on it. The market price of that product in each time period depends on the total quantity placed in the market. We show that this is a potential game with possibly multiple pure Nash equilibria. We then investigate the plausibility of these equilibria to predict the game outcome by evaluating the difficulty of computing them. If the game has a single period, we prove that an equilibrium can be found in polynomial time, but it is weakly NP hard to find an optimal pure Nash equilibrium (with respect to a given equilibrium refinement). If the game has no variable production and inventory costs, we prove that a pure Nash equilibrium can be computed in polynomial time.

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We aim to investigate a new class of games, where each player's set of strategies is a union of polyhedra. These are called integer programming games. To motivate our work, we describe some practical examples suitable to be modeled under this paradigm. We analyze the problem of determining whether or not a Nash equilibria exists for an integer programming game, and demonstrate that it is complete for the second level of the polynomial hierarchy.

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In the increasingly complex service environment, value is cocreated through webs of interactions between provider networks and customer networks. This is evident in healthcare services, where well-being can be achieved only through the joint efforts of professional healthcare networks and patient networks. Addressing the challenge of creating network-level services, the service design for value networks (SD4VN) method designs services as enablers of many-to-many value cocreating interactions among network actors. By integrating previous research on value networks and service design, SD4VN develops a process and a set of models beyond supporting dyadic (customer-service provider) interactions to understanding the interrelated activities, interactions, and goals of network actors and designing services to support the different actors in reaching their goals with balanced centricity. Following a design science research approach, this paper presents the SD4VN method and reports on a case application of the method used to design the Portuguese national electronic health record service Plataforma de Dados da Saude (PDS). The case application involved focus groups, indepth interviews, and participatory design sessions with over 170 participants at different service design stages, showing the importance of designing a balanced, integrated service. The case application also shows how SD4VN can support a wider adoption of the service and improve the health service system.

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Service design is a multidisciplinary field dedicated to create new and innovative services. To accomplish this goal, service design resorts to contributions from other disciplines such as service management, marketing, information systems and interaction design. However, service design lacks dedicated methods and models that integrate the contributions from these disciplines. Design science research (DSR) offers a solid methodology to develop such artifacts and is already starting to be used in service research. To show how DSR can support service design, this article presents two new service design methods that have been developed using DSR and examines the process followed for developing them. Building on these methods, the article discusses how DSR can leverage service design characteristics of multidisciplinarity, human-centeredness and creativity, to develop further knowledge contributions for service design. Finally, the challenges posed by using DSR in service design and service research are also discussed, as well as ways to address those challenges. © 2018, Springer Nature Switzerland AG.

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