54 research outputs found

    On characterization of the core of lane covering games via dual solutions

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    The lane covering game (LCG) is a cooperative game where players cooperate to reduce the cost of cycles that cover their required lanes on a network. We discuss the possibilities/impossibilities of a complete characterization of the core via dual solutions in LCGs played among a collection of shippers, each with a number of service require-ments along some lanes, and show that such a complete characterization is possible if each shipper has at most one service requirement

    Supply chain finance : a conceptual framework to advance research

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    Supply Chain Finance (SCF) arrangements aim to add value by taking a cooperative approach to financing in the supply chain. SCF has recently enjoyed considerable attention from industry, and providers of capital and technology are investing in platforms to facilitate new applications. A limited number of theoretical and empirical studies on the topic have been published. Current trends suggest, however, that the landscape of SCF is becoming increasingly complex and diverse. We describe some key developments and their implications for firms that (may) implement an SCF arrangement. In particular, we show that strategic and tactical considerations may impact the value of these arrangements. Failure to recognize alternatives and associated trade-offs may entail missed opportunities for firms. We present a framework that positions SCF concepts and shows the need for further research. We conclude with observations on managerial relevance

    Tracebook : a dynamic checklist support system

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    It has recently been demonstrated that checklist scan enable significant improvements to patient safety. However, their clinical acceptance is significantly lower than expected. This is due to the lack of good support systems. Specifically, support systems are too static: this holds for paper-based support as well as for electronic systems that digitize paper-based support naively. Both approaches are independent from clinical process and clinical context. In this paper, we propose a process-oriented and context-aware dynamic checklist support system: Tracebook. This system supports the execution of complex clinical processes and rules involving data from Electronic Medical Record systems. Workflow activities and forms are specific to individual patients based on clinical rules and they are dispatched to the right user automatically based on a process model. Besides describing the Tracebook functionality in general, this paper demonstrates the support system specifically on an example application that we are preparing for a controlled clinical evaluation. At last we discuss the difference between Tracebook and other support systems which also rely on a checklist format

    A unified race algorithm for offline parameter tuning

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    This paper proposes uRace, a unified race algorithm for efficient offline parameter tuning of deterministic algorithms. We build on the similarity between a stochastic simulation environment and offline tuning of deterministic algorithms, where the stochastic element in the latter is the unknown problem instance given to the algorithm. Inspired by techniques from the simulation optimization literature, uRace enforces fair comparisons among parameter configurations by evaluating their performance on the same training instances. It relies on rapid statistical elimination of inferior parameter configurations and an increasingly localized search of the parameter space to quickly identify good parameter settings. We empirically evaluate uRace by applying it to a parameterized algorithmic framework for loading problems at ORTEC, a global provider of software solutions for complex decision-making problems, and obtain competitive results on a set of practical problem instances from one of the world's largest multinationals in consumer packaged goods

    Dynamics and equilibria under incremental horizontal differentiation on the Salop circle

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    We study product differentiation on a Salop circle when firms relocate incrementally due to bounded rationality. We prove that, under common assumptions on demand, firms relocate only when two or more firms target the same niche. In any other case, there is no incentive for any firm to relocate incrementally. We prove that all distributions in which firms are sufficiently far apart in product space are unstable Nash equilibria. We prove, in particular, that the classical equidistant distribution is an unstable Nash equilibrium that cannot emerge from another distribution. However, we show that if each firm is engaged in head-on rivalry with one other competitor, the industry converges to a ’equidistantesque’ equilibrium of clusters of rivals

    Maintenance policy selection for ships : finding the most important criteria and considerations

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    Maintenance of technical capital assets is gaining increasing attention, as maintenance is an important contributor to reach the intended life-time of these expensive assets. This paper focusses on maintenance policy selection (MPS) for ships using the Analytic Hierarchy Process. It builds on earlier research where we have investigated MPS specifically for naval ships. Here, we aim to generalize our findings on naval ships towards ships in general, and to elicit the most important criteria for ship MPS. We propose an improved hierarchy of criteria that we use during six workshops at six different companies to investigate MPS. We conclude that it is possible to obtain meaningful outcomes using a single hierarchy of criteria at multiple companies considering various ship types. The workshops reveal that crew safety is the most important criterion when selecting a aintenance policy, followed by reliability and availability—surprisingly, costs minimization is only moderately important. Furthermore, the workshops reveal that softer criteria, such as experience with maintenance and planability, must be included in the MPS process. Finally, we see that, for ship MPS, failure-based maintenance is never preferred, and that there is no clear preference for either time/use-based maintenance or condition-based maintenance

    A condition-based maintenance policy for multi-component systems with a high maintenance setup cost

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    Condition-based maintenance (CBM) is becoming increasingly important due to the development of advanced sensor and ICT technology, so that the condition data can be collected remotely. We propose a new CBM policy for multi-component systems with continuous stochastic deteriorations. To reduce the high setup cost of maintenance, a joint maintenance interval is proposed. With the joint maintenance interval and control limits of components as decision variables, we develop a model for the minimization of the average long-run maintenance cost rate of the systems. Moreover, a numerical study on a case of a wind power farm consisting of a large number of non-identical components is performed, including a sensitivity analysis. At last, our policy is compared to a corrective-maintenance-only policy

    Scheduling the scheduling task : a time management perspective on scheduling

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    Time is the most critical resource at the disposal of schedulers. Hence, an adequate management of time from the schedulers may impact positively on the scheduler’s productivity and responsiveness to uncertain scheduling environments. This paper presents a field study of how schedulers make use of their time and makes explicit what time-management decisions and behaviors are available to a scheduler. Based on observations of the field study, we propose a framework to classify and specify key characteristics of common tasks to the scheduling job in terms of their impact on the workflow and workload of a scheduler. We then discuss how such a framework may be used to assess alternative time-management decisions of a scheduler

    MyPHRMachines : personal health desktops in the cloud

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    Personal Health Records (PHRs) should remain the lifelong property of patients, who should be enabled to show them conveniently and securely to selected caregivers and institutions. Current solutions for PHRs focus on standard data exchange formats and transformations to move data across health information systems. In this paper we present MyPHRMachines, a PHR system taking a radically new architectural solution to health record interoperability. In MyPHRMachines, health-related data and the application software to view and/or analyze it are separately deployed in the PHR system. After uploading their medical data to MyPHRMachines, patients can access them again from remote virtual machines that contain the right software to visualize and analyze them without any conversion. Patients can share their remote virtual machine session with selected caregivers, who will need only aWeb browser to access the pre-loaded fragments of their lifelong PHR. We discuss a prototype of MyPHRMachines applied to two use cases, i.e. radiology image sharing and personalized medicine. The first use case demonstrates the ability of patients to build robust PHRs across the space and time dimensions, whereas the second use case demonstrates the ability of MyPHRMachines to preserve the privacy of PHR data deployed in the cloud

    A value network development model and implications for innovation and production network management

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    In managing their value network, firms have to balance current and future value concerns and own and network partners’ concerns. Firms generate immediate value through manufacturing and selling the current generation of products together with other firms in its production network and generate future value by developing a new generation of products with other firms and research institutes in its innovation network. Product innovation and production often take place simultaneously and recurrently. We take the discernible production and innovation activities to occur in co-evolving network layers. We formulate a biplex value network development model that lays out the temporal pattern of production and innovation activities in the value network. We introduce terminology to pinpoint temporal interactions between the innovation and production activities. We study several exemplary complications in the cross-table of inter- and intragenerational interactions versus interactions within and across network layers
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