940 research outputs found

    Study on the reward and compensation policy for the engagement of social force in maritime search and rescue in China

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    SAMUDRA Report No.23, September 1999

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    A Study of Optimal Search and Rescue Operations Planning Problems

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    Search and Rescue (SAR) systems are vital to provide the quick response for saving lives in the first moments of natural and man-made calamities. In this dissertation, we present and discuss factors related to SAR operations planning and develop three SAR mathematical problems. In the first part we present an overview of SAR operations, highlighting questions affecting aerial search and rescue operations since it is the main object of our Thesis. In the second part, we consider an aerial fleet planning as a resource allocation problem and propose variations in the objective function of a binary integer programming (BIP) model according to different priorities related to area, time and type of the searching operation in high seas. We then study the problem for planning rescue missions in oceanic areas, modeled as a vehicle routing problem considering a heterogeneous fleet of vehicles and respective displacements during the operation. A BIP model is proposed and routing choices are assisted by probabilistic demands at each location that, when visited, may update previous decisions. In the fifth part, we consider the problem for planning a long-range mass rescue operation, modeled as an aircraft routing problem with pick-up and delivering, weight and endurance limits. A BIP model is proposed to minimize the flying time and feasible routes depend on factors such as aircraft endurance, fuel consumption rate, payload, take-off and landing weights, local demand and airfield capacities to operate different types of aircraft. The dissertation ends with conclusions and identified issues for future research

    Game Assessment For Miltary Application

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    The primary purpose of conducting this research was to establish game assessment guidelines and characteristics for integrating elected characteristics of games into ongoing instructional approaches. The cost of repurposing commercial-off-the-shelf (COTS) games could offer a considerably lower cost alternative than the cost of creating a new instructional game developed for a specific instructional goal. The McNeese Game Assessment Tool (MGAT), created for the assessment of games in this usability study, is currently in a beta stage and was found to have potential for future game assessment. The overall assessment indicated that the tool was effective in analyzing game products for reuse potential and that the five instruments that make up the tool did meet the purpose of the design. However, the study also indicated that the instruments needed recommended modifications and further testing with a larger population group before the tool could be utilized. The assessment process identified in this study was a step forward in the area of game and simulation integration research. This study indicated that more research is needed in the area of instructional design to enhance instructional integration goals for future game, simulation and training applications

    Feasibility and systems definition study for Microwave Multi-Application Payload (MMAP)

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    Work completed on three Shuttle/Spacelab experiments is examined: the Adaptive Multibeam Phased Array Antenna (AMPA) Experiment, Electromagnetic Environment Experiment (EEE) and Millimeter Wave Communications Experiment (MWCE). Results included the definition of operating modes, sequence of operation, radii of operation about several ground stations, signal format, foot prints of typical orbits and preliminary definition of ground and user terminals. Conceptual hardware designs, Spacelab interfaces, data handling methods, experiment testing and verification studies were included. The MWCE-MOD I was defined conceptually for a steerable high gain antenna

    Integrating UAS Flocking Operations with Formation Drag Reduction

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    Craig Reynolds, in the seminal research into simulated flocking, developed a methodology to guide a flock of birds using three rules: collision avoidance, flock centering, and velocity matching. By modifying these rules, a methodology was created so that each aircraft in a flock maintains a precise position relative to the preceding aircraft. By doing so, each aircraft experiences a decrease in induced aerodynamic drag and increase in fuel efficiency. Flocks of semi-autonomous aircraft present the warfighter with a wide array of capabilities for accomplishing missions more effectively. By introducing formation drag reduction, overall fuel consumption is reduced while range and endurance increase, expanding war planners\u27 options. A simulation was constructed to determine the feasibility of the drag reduction flock in a two-dimensional environment using a drag benefit map constructed from existing research. Due to both agent interaction and wind gust variability, the optimal position for drag reduction presented a severe collision hazard, and drag savings were much more sensitive to lateral (wingtip) position than longitudinal (streamwise) position. By increasing longitudinal spacing, the collision hazard was greatly reduced and a 10-aircraft flock demonstrated a 9.7% reduction in total drag and 14.5% increase in endurance over a mock target

    A Case Study Exploring Organizational Development and Performance Management in the Operational Infrastructure of a Professional Working Organization, Using Academic Constructs

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    Curriculum, as a concept, has been historically associated with traditional schooling, but the reality is that its application extends to many arenas beyond academia. Through the case study lens, this dissertation utilized the ideologies of curricular theorists John Dewey, John Franklin Bobbitt, and Ralph Tyler to explore how intended, enacted, and assessed curricula phases can integrate into a professional working organization’s comprehensive functionality and materialize into the planning and implementation of its operational infrastructure. Following content analysis of a selected institution’s operational system, using closed codes, a descriptive comprehensive curriculum was designed to address the research purpose of understanding employee performance and organizational outcomes. Findings indicated that curricular phases are inherently embedded into the organizational development and performance management of nonacademic spaces; moreover, the framework of an organization’s operational infrastructure consists largely of curriculum elements. The primary research implication invokes being able to manage the efficiency and effectiveness levels of (a) personnel unit performance and (b) the workplace environment, through curriculum analysis and prescription

    Aeronautical Engineering: A continuing bibliography with indexes, supplement 110

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    This bibliography lists 504 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1979

    Mission-based mobility models for UAV networks

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    Las redes UAV han atraído la atención de los investigadores durante la última década. Las numerosas posibilidades que ofrecen los sistemas single-UAV aumentan considerablemente al usar múltiples UAV. Sin embargo, el gran potencial del sistema multi-UAV viene con un precio: la complejidad de controlar todos los aspectos necesarios para garantizar que los UAVs cumplen la misión que se les ha asignado. Ha habido numerosas investigaciones dedicadas a los sistemas multi-UAV en el campo de la robótica en las cuales se han utilizado grupos de UAVs para diferentes aplicaciones. Sin embargo, los aspectos relacionados con la red que forman estos sistemas han comenzado a reclamar un lugar entre la comunidad de investigación y han hecho que las redes de UAVs se consideren como un nuevo paradigma entre las redes multi-salto. La investigación de redes de UAVs, de manera similar a otras redes multi-salto, se divide principalmente en dos categorías: i) modelos de movilidad que capturan la movilidad de la red, y ii) algoritmos de enrutamiento. Ambas categorías han heredado muchos algoritmos que pertenecían a las redes MANET, que fueron el primer paradigma de redes multi-salto que atrajo la atención de los investigadores. Aunque hay esfuerzos de investigación en curso que proponen soluciones para ambas categorías, el número de modelos de movilidad y algoritmos de enrutamiento específicos para redes UAV es limitado. Además, en el caso de los modelos de movilidad, las soluciones existentes propuestas son simplistas y apenas representan la movilidad real de un equipo de UAVs, los cuales se utilizan principalmente en operaciones orientadas a misiones, en la que cada UAV tiene asignados movimientos específicos. Esta tesis propone dos modelos de movilidad basados en misiones para una red de UAVs que realiza dos operaciones diferentes. El escenario elegido en el que se desarrollan las misiones corresponde con una región en la que ha ocurrido, por ejemplo, un desastre natural. La elección de este tipo de escenario se debe a que en zonas de desastre, la infraestructura de comunicaciones comúnmente está dañada o totalmente destruida. En este tipo de situaciones, una red de UAVs ofrece la posibilidad de desplegar rápidamente una red de comunicaciones. El primer modelo de movilidad, llamado dPSO-U, ha sido diseñado para capturar la movilidad de una red UAV en una misión con dos objetivos principales: i) explorar el área del escenario para descubrir las ubicaciones de los nodos terrestres, y ii) hacer que los UAVs converjan de manera autónoma a los grupos en los que se organizan los nodos terrestres (también conocidos como clusters). El modelo de movilidad dPSO-U se basa en el conocido algoritmo particle swarm optimization (PSO), considerando los UAV como las partículas del algoritmo, y también utilizando el concepto de valores dinámicos para la inercia, el local best y el neighbour best de manera que el modelo de movilidad tenga ambas capacidades: la de exploración y la de convergencia. El segundo modelo, denominado modelo de movilidad Jaccard-based, captura la movilidad de una red UAV que tiene asignada la misión de proporcionar servicios de comunicación inalámbrica en un escenario de mediano tamaño. En este modelo de movilidad se ha utilizado una combinación del virtual forces algorithm (VFA), de la distancia Jaccard entre cada par de UAVs y metaheurísticas como hill climbing y simulated annealing, para cumplir los dos objetivos de la misión: i) maximizar el número de nodos terrestres (víctimas) que se encuentran bajo el área de cobertura inalámbrica de la red UAV, y ii) mantener la red UAV como una red conectada, es decir, evitando las desconexiones entre UAV. Se han realizado simulaciones exhaustivas con herramientas software específicamente desarrolladas para los modelos de movilidad propuestos. También se ha definido un conjunto de métricas para cada modelo de movilidad. Estas métricas se han utilizado para validar la capacidad de los modelos de movilidad propuestos de emular los movimientos de una red UAV en cada misión.UAV networks have attracted the attention of the research community in the last decade. The numerous capabilities of single-UAV systems increase considerably by using multiple UAVs. The great potential of a multi-UAV system comes with a price though: the complexity of controlling all the aspects required to guarantee that the UAV team accomplish the mission that it has been assigned. There have been numerous research works devoted to multi-UAV systems in the field of robotics using UAV teams for different applications. However, the networking aspects of multi-UAV systems started to claim a place among the research community and have made UAV networks to be considered as a new paradigm among the multihop ad hoc networks. UAV networks research, in a similar manner to other multihop ad hoc networks, is mainly divided into two categories: i) mobility models that capture the network mobility, and ii) routing algorithms. Both categories have inherited previous algorithms mechanisms that originally belong to MANETs, being these the first multihop networking paradigm attracting the attention of researchers. Although there are ongoing research efforts proposing solutions for the aforementioned categories, the number of UAV networks-specific mobility models and routing algorithms is limited. In addition, in the case of the mobility models, the existing solutions proposed are simplistic and barely represent the real mobility of a UAV team, which are mainly used in missions-oriented operations. This thesis proposes two mission-based mobility models for a UAV network carrying out two different operations over a disaster-like scenario. The reason for selecting a disaster scenario is because, usually, the common communication infrastructure is malfunctioning or completely destroyed. In these cases, a UAV network allows building a support communication network which is rapidly deployed. The first mobility model, called dPSO-U, has been designed for capturing the mobility of a UAV network in a mission with two main objectives: i) exploring the scenario area for discovering the location of ground nodes, and ii) making the UAVs to autonomously converge to the groups in which the nodes are organized (also referred to as clusters). The dPSO-U mobility model is based on the well-known particle swarm optimization algorithm (PSO), considering the UAVs as the particles of the algorithm, and also using the concept of dynamic inertia, local best and neighbour best weights so the mobility model can have both abilities: exploration and convergence. The second one, called Jaccard-based mobility model, captures the mobility of a UAV network that has been assigned with the mission of providing wireless communication services in a medium-scale scenario. A combination of the virtual forces algorithm (VFA), the Jaccard distance between each pair of UAVs and metaheuristics such as hill climbing or simulated annealing have been used in this mobility model in order to meet the two mission objectives: i) to maximize the number of ground nodes (i.e. victims) under the UAV network wireless coverage area, and ii) to maintain the UAV network as a connected network, i.e. avoiding UAV disconnections. Extensive simulations have been performed with software tools that have been specifically developed for the proposed mobility models. Also, a set of metrics have been defined and measured for each mobility model. These metrics have been used for validating the ability of the proposed mobility models to emulate the movements of a UAV network in each mission
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