195,507 research outputs found

    Scheduling in healthcare with multiple resources

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    The need for improving efficiency in healthcare is motivated largely by increasing global costs of healthcare. One possibility for improvement is in the optimization of the many schedules found within healthcare. This dissertation focuses on just that for two scheduling problems found within healthcare: the appointment scheduling problem and the master surgery scheduling problem. We first look at the appointment scheduling problem – the problem of assigning time slots to patients booking an appointment at a clinic – examining the various ways in which the randomness of this problem is accounted for, and generalising the problem so that its solutions may be used in a wider range of settings in practice. We consider the application of phase-type distributions as well as simulation and analytical approaches, and we optimize appointment schedules for settings both with multiple healthcare providers, and where patients may arrive in batches rather than one-by-one as is usual. Hereafter, we look at a practical scheduling issue, reporting upon the optimization – via mixed integer linear programming – and subsequent implementation of a surgery schedule for a medium sized hospital in the Netherlands. This problem requires assigning surgical specialties to operate in a given room at a given time during a four-week long repeating schedule; the number of possible combinations of which grows extraordinarily fast, even for a small number of specialties and rooms. In this dissertation, we present the method by which we handled the size of the problem, and pay particular attention to the matter of expectations management throughout the project

    Design choices for agent-based control of AGVs in the dough making process

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    In this paper we consider a multi-agent system (MAS) for the logistics control of Automatic Guided Vehicles (AGVs) that are used in the dough making process at an industrial bakery. Here, logistics control refers to constructing robust schedules for all transportation jobs. The paper discusses how alternative MAS designs can be developed and compared using cost, frequency of messages between agents, and computation time for evaluating control rules as performance indicators. Qualitative design guidelines turn out to be insufficient to select the best agent architecture. Therefore, we also use simulation to support decision making, where we use real-life data from the bakery to evaluate several alternative designs. We find that architectures in which line agents initiate allocation of transportation jobs, and AGV agents schedule multiple jobs in advance, perform best. We conclude by discussing the benefits of our MAS systems design approach for real-life applications

    Investigating the Efficiency of ITS Cooperative Systems for a Better Use of Urban Transport Infrastructures: The iTETRIS Simulation Platform

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    The use of cooperative ITS communication systems, supporting driving through the dynamic exchange of Vehicle-to- Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages, is a potential candidate to improve the economical and societal welfare. The application of such systems for novel cooperative traffic management strategies can introduce a lot of beneficial effects not only for road safety, but also for the economy related to transportation systems and the environmental impact. Despite this apparent set of promising features, City Road Authorities, which hold a key-role in determining the final adoption of such systems, still look at cooperative systems without sharing a clear opinion. This is mainly due to the current lack of definitive and solid evidences of the effectiveness of such systems when applied in the real world. In order to fill this gap and let Road Authorities estimate the usefulness of such technologies in achieving the objectives dictated by cities’ traffic management policies, the EU consortium iTETRIS is developing a simulation platform for large scale testing of traffic management solutions making use of cooperative ITS systems. Thanks to its own distinguishing features, iTETRIS aims at becoming a good supporting tool for Road Authorities to implement preliminary tests on the effectiveness of ITS solutions prior to investing money for the physical deployment of the communication infrastructures allowing their functioning

    Supporting decision-making in the building life-cycle using linked building data

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    The interoperability challenge is a long-standing challenge in the domain of architecture, engineering and construction (AEC). Diverse approaches have already been presented for addressing this challenge. This article will look into the possibility of addressing the interoperability challenge in the building life-cycle with a linked data approach. An outline is given of how linked data technologies tend to be deployed, thereby working towards a “more holistic” perspective on the building, or towards a large-scale web of “linked building data”. From this overview, and the associated use case scenarios, we conclude that the interoperability challenge cannot be “solved” using linked data technologies, but that it can be addressed. In other words, information exchange and management can be improved, but a pragmatic usage of technologies is still required in practice. Finally, we give an initial outline of some anticipated use cases in the building life-cycle in which the usage of linked data technologies may generate advantages over existing technologies and methods

    Real Option Valuation of a Portfolio of Oil Projects

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    Various methodologies exist for valuing companies and their projects. We address the problem of valuing a portfolio of projects within companies that have infrequent, large and volatile cash flows. Examples of this type of company exist in oil exploration and development and we will use this example to illustrate our analysis throughout the thesis. The theoretical interest in this problem lies in modeling the sources of risk in the projects and their different interactions within each project. Initially we look at the advantages of real options analysis and compare this approach with more traditional valuation methods, highlighting strengths and weaknesses ofeach approach in the light ofthe thesis problem. We give the background to the stages in an oil exploration and development project and identify the main common sources of risk, for example commodity prices. We discuss the appropriate representation for oil prices; in short, do oil prices behave more like equities or more like interest rates? The appropriate representation is used to model oil price as a source ofrisk. A real option valuation model based on market uncertainty (in the form of oil price risk) and geological uncertainty (reserve volume uncertainty) is presented and tested for two different oil projects. Finally, a methodology to measure the inter-relationship between oil price and other sources of risk such as interest rates is proposed using copula methods.Imperial Users onl

    Reviews

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    Danny Saunders and Nina Smalley (eds.), The International Simulation and Gaming Research Yearbook — Volume 8: Simulations and Games for Transition and Change, London: Kogan Page, 2000. ISBN: 0–7494–3397–3. Hardback, viii+271 pages, £40.00

    Acumen: An interactive multimedia simulation based on situated learning theory

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    This paper describes the development and evaluation of a multimedia simulation for teaching research skills to business students. Graphics, sound and video are used to create semi- realistic ' microworlds' which students explore in order to solve a relatively unstructured problem, a process quite different to learning from textbooks, lectures or videos. One advantage of microworlds is that students construct meaning by actively and selectively working through a variety of information sources, a process which mimics real-world learning and enhances higher- order learning outcomes. We describe the theoretical principles used in designing the simulation, particularly situated learning theory which claims a number of advantages for teaching that is 'situated' in the context of real world problems. There is also evidence that the 'immersive' quality of microworlds may be more motivating than other teaching/ learning modes, at least to some students. As the technology for creating media- rich simulations is still new, we discuss the issue of how realistic simulations should be. Our multimedia package can be related to a long tradition of teaching methods in business that attempt to put theoretical principles into life-like contexts, via case studies, experiential learning, internships, or real-world projects. The advantages and disadvantages of computer microworlds over such methods are explored

    Applications of lean thinking: a briefing document

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    This report has been put together by the Health and Care Infrastructure Research and Innovation Centre (HaCIRIC) at the University of Salford for the Department of Health. The need for the report grew out of two main simple questions, o Is Lean applicable in sectors other than manufacturing? o Can the service delivery sector learn from the success of lean in manufacturing and realise the benefits of its implementation?The aim of the report is to list together examples of lean thinking as it is evidenced in the public and private service sector. Following a review of various sources a catalogue of evidence is put together in an organised manner which demonstrates that Lean principles and techniques, when applied rigorously and throughout an entire organization/unit, they can have a positive impact on productivity, cost, quality, and timely delivery of services

    Operations research and computers

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