3,393 research outputs found

    Quantification of Risk for USAF Fire and Emergency Services Flights as a Result of Shortage in Manpower

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    The United States Air Force (USAF) is currently experiencing a period of high operations tempo and overseas deployments have become frequent. These deployments will leave home installations short manned. Some amount of risk is incurred by the home installation as a result of the short manning. For an organization, such as an USAF Fire and Emergency Services (FES) flight, whose primary responsibility is the protection of life and property, the incurred risk could be catastrophic. Still no attempt has been made to quantify risk in terms of manpower for the USAF FES flights. The primary purpose of this research was to develop and validate a methodology to quantify risk in terms of manpower for FES flights. This research develops a decision tool to provide insight to FES Fire Chiefs on the risk associated with specific manpower decisions. The methodology was validated using data from Dyess Air Force Base FES flight. A secondary goal of the research was to determine a cost/benefit relationship between the risk level and the cost to backfill deployed firefighter positions with contract labor. The result was a decision tree model and pareto optimal graphs for the risk to manpower level and the cost/benefit relationship

    Auction-Based Task Allocation and Motion Planning for Multi-Robot Systems with Human Supervision

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    This paper presents a task allocation strategy for a multi-robot system with a human supervisor. The multi-robot system consists of a team of heterogeneous robots with different capabilities that operate in a dynamic scenario that can change in the robots’ capabilities or in the operational requirements. The human supervisor can intervene in the operation scenario by approving the final plan before its execution or forcing a robot to execute a specific task. The proposed task allocation strategy leverages an auction-based method in combination with a sampling-based multi-goal motion planning. The latter is used to evaluate the costs of execution of tasks based on realistic features of paths. The proposed architecture enables the allocation of tasks accounting for priorities and precedence constraints, as well as the quick re-allocation of tasks after a dynamic perturbation occurs –a crucial feature when the human supervisor preempts the outcome of the algorithm and makes manual adjustments. An extensive simulation campaign in a rescue scenario validates our approach in dynamic scenarios comprising a sensor failure of a robot, a total failure of a robot, and a human-driven re-allocation. We highlight the benefits of the proposed multi-goal strategy by comparing it with single-goal motion planning strategies at the state of the art. Finally, we provide evidence for the system efficiency by demonstrating the powerful synergistic combination of the auction-based allocation and the multi-goal motion planning approach

    RoboCup rescue : development of inteligent cooperative agents

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    Mestrado em Engenharia de Computadores e TelemáticaO trabalho desenvolvido nesta dissertação tem como tema o desenvolvimento de um agente inteligente com coordenação e comunicação no ambiente RoboCup Rescue. No RoboCup Rescue existem seis tipos de agentes, no entanto nesta tese só dois agentes foram desenvolvidos, especificamente o tipo de agentes Ambulâncias e Centros de Ambulâncias. O tipo de agente Ambulância é o elemento responsável pelo salvamento de civis na cidade virtual que constitui o ambiente RoboCup Rescue. Para cumprir essa tarefa da forma mais eficiente possível conta com coordenação e comunicação com outros agentes do mesmo tipo, e com os Centros de Ambulâncias. O comportamento da ambulância é modelado tanto para situações em que o Centro de Ambulâncias está presente durante a simulação, podendo, portanto, delegar funções para o Centro; como em situações em que o Centro não está presente, e, por isso, as ambulâncias estão encarregues de todo o processamento dos dados e de todas as tomadas de decisões. As actividades desenvolvidas pelas ambulâncias podem ser resumidas a duas: pesquisa e salvamento. Para a primeira as soluções passam muito pelo uso de algoritmos estudados em Teoria de Grafos, já que a cidade virtual é, na sua essência, um grafo, e são necessárias soluções para problemas como visitar o mapa completamente e determinar o caminho mais rápido entre dois nós. Na parte de salvamento a coordenação tem um grande papel a desempenhar.É necessário determinar que ambulâncias devem ir socorrer que civil, e quantas ambulâncias devem ajudar; ou que ambulâncias que devem continuar com a pesquisa do mapa. Ou seja, a coordenação é vital para uma utilização eficiente dos recursos disponíveis, e, consequentemente, uma boa pontuação. ABSTRACT: The work developed in this thesis has as background the development of an intelligent agent with coordination and communication in the environment of the RoboCup Rescue. RoboCup Rescue has six types of agents, however only two were developed in this thesis, specifically Ambulances and Ambulance Centers. The type of agent Ambulance is the element responsable for the rescuing of civilians in the virtual city which comprises the environment of RoboCup Rescue. To fulfill this task in the most efficient way possible it relies on coordination and communication with other agents of the same type, as well as Ambulance Centers. The behavior of an ambulance is modeled for situations when an Ambulance Center is available during the simulation, thus allowing the ambulances the possibility of dividing some of the processing and decision making; or, for situations when a center is not available and it is up to the ambulances to do make all of the decisions, and do all of the processing. The activities performed by the ambulances can be summarized in two: search, and rescue. For the first, many of the solutions may be provided by algorithms studied in Graph Theory, since the virtual city is, in its essence, a graph, and its necessary solutions to problems such as visit the city entirely, and determine the shortest path between two locations, or nodes. In the rescuing part, the coordination has a very big part to play. It is necessary to choose which ambulances should rescue a civilian, and how many should help doing it; or, which ambulances should continue searching the city for more civilians. In other words, coordination is vital for an efficient allocation of available resources, and, ultimately, a good score

    Periodic Review, Push Inventory Policies for Remanufacturing

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    Sustainability has become a major issue in most economies, causing many leading companies to focus on product recovery and reverse logistics. This research is focused on product recovery, and in particular on production control and inventory management in the remanufacturing context. We study a remanufacturing facility that receives a stream of returned products according to a Poisson process. Demand is uncertain and also follows a Poisson process. The decision problems for the remanufacturing facility are when to release returned products to the remanufacturing line and how many new products to manufacture. We assume that remanufactured products are as good as new. In this paper, we employ a "push" policy that combines these two decisions. It is well known that the optimal policy parameters are difficult to find analytically; therefore, we develop several heuristics based on traditional inventory models. We also investigate the performance of the system as a function of return rates, backorder costs and manufacturing and remanufacturing lead times; and we develop approximate lower and upper bounds on the optimal solution. We illustrate and explain some counter-intuitive results and we test the performance of the heuristics on a set of sample problems. We find that the average error of the heuristics is quite low.inventory;reverse logistics;remanufacturing;environment;heuristics

    Aerospace medicine and biology: A continuing bibliography with indexes, supplement 162, January 1977

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    This bibliography lists 189 reports, articles, and other documents introduced into the NASA scientific and technical information system in December 1976

    Coalition Modeling In Humanitarian Assistance Operations

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    Multinational operations are carried out to achieve military and diplomatic objectives in various regions. Such operations derive a great deal of benefits from sharing budgets, political legitimacy, sharing each national experience and technological resources, and so forth. However, a coalition, one structure of multinational operations, often involves serious challenges in such areas as command and control, logistic support, communication and language, training, and intelligence and information due to its ad hoc characteristics. This research reviews general problems in a coalition operation, and develops the Coalition Operation Planning Model to assist coalition commanders or staff in producing an efficient operational plan. In this model, goal programming is employed to formulate the coalition problems with multiple objectives. The proposed model is composed of three sub-models: the Coalition Mission-Unit Allocation Model, the Coalition Mission-Support Model, and the Coalition Mission-Unit Grouping Model. The first sub-model is designed to find an optimized resource allocation by applying the shortest path problem and effectiveness functions. The second sub-model is developed to obtain an optimized logistics support plan by using the multi-commodity network flow. Finally, the third sub-model is designed to combine small units into one workable independent unit by using the quadratic assignment problem. The models are demonstrated with a notional humanitarian assistance operation

    Online Optimisation of Casualty Processing in Major Incident Response

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    Recent emergency response operations to Mass Casualty Incidents (MCIs) have been criticised for a lack of coordination, implying that there is clear potential for response operations to be improved and for corresponding benefits in terms of the health and well-being of those affected by such incidents. In this thesis, the use of mathematical modelling, and in particular optimisation, is considered as a means with which to help improve the coordination of MCI response. Upon reviewing the nature of decision making in MCIs and other disaster response operations in practice, this work demonstrates through an in-depth review of the available academic literature that an important problem has yet to be modelled and solved using an optimisation methodology. This thesis involves the development of such a model, identifying an appropriate task scheduling formulation of the decision problem and a number of objective functions corresponding to the goals of the MCI response decision makers. Efficient solution methodologies are developed to allow for solutions to the model, and therefore to the MCI response operation, to be found in a timely manner. Following on from the development of the optimisation model, the dynamic and uncertain nature of the MCI response environment is considered in detail. Highlighting the lack of relevant research considering this important aspect of the problem, the optimisation model is extended to allow for its use in real-time. In order to allow for the utility of the model to be thoroughly examined, a complementary simulation is developed and an interface allowing for its communication with the optimisation model specified. Extensive computational experiments are reported, demonstrating both the danger of developing and applying optimisation models under a set of unrealistic assumptions, and the potential for the model developed in this work to deliver improvements in MCI response operations

    The 1990 Johnson Space Center bibliography of scientific and technical papers

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    Abstracts are presented of scientific and technical papers written and/or presented by L. B. Johnson Space Center (JSC) authors, including civil servants, contractors, and grantees, during the calendar year of 1990. Citations include conference and symposium presentations, papers published in proceedings or other collective works, seminars, and workshop results, NASA formal report series (including contractually required final reports), and articles published in professional journals
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