2,620 research outputs found

    12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

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    Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin

    The assessment of the relationship between information technology (IT) and airport performance

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    The evolution of the airport business is demonstrated by airports that are adopting new business strategies and commercial models, which allow them to be, for example, service providers instead of real-estate managers, with the focus on cost reduction and increasing non-aeronautical (commercial) revenues. Information technology (IT) can be used by airports to achieve their business goals, such as enhancing performance by delivering cost reductions and generating additional revenue streams. Airports operate in an increasingly competitive and dynamic market, with the aim of attracting a larger share of hub traffic from neighbouring airports. Therefore, financial and operational performance will be key elements for airlines when choosing a new airport destination. The research shows that airports are more focused on passenger satisfaction, resulting in airport performance indicators that have the passenger at its operational core and performance targets (e.g. Airport Service Quality passenger satisfaction survey). IT plays an important role in increasing airport performance through the automation of processes such as the deployment of common-use check-in desks and self-service check-in kiosks. Studies of other industries have shown evidence that IT impacts firm performance, but there have been few studies related to the airport industry. Thus, the aim of this research is to assess the relationship between IT and airport performance, and it proposes a conceptual framework to assess the relationship between IT and airport performance by drawing from studies in other industries. Two methodologies were used in this research, the first one was the case study, and the second one was the online survey. The case studies consisted of 16 faceto- face interviews with senior staff representing two airports in Asia, one airport in Australia, and one airport in Europe. The case studies result show that there is a relationship between IT and airport performance ... [cont.]

    The assessment of the relationship between information technology (IT) and airport performance

    Get PDF
    The evolution of the airport business is demonstrated by airports that are adopting new business strategies and commercial models, which allow them to be, for example, service providers instead of real-estate managers, with the focus on cost reduction and increasing non-aeronautical (commercial) revenues. Information technology (IT) can be used by airports to achieve their business goals, such as enhancing performance by delivering cost reductions and generating additional revenue streams. Airports operate in an increasingly competitive and dynamic market, with the aim of attracting a larger share of hub traffic from neighbouring airports. Therefore, financial and operational performance will be key elements for airlines when choosing a new airport destination. The research shows that airports are more focused on passenger satisfaction, resulting in airport performance indicators that have the passenger at its operational core and performance targets (e.g. Airport Service Quality passenger satisfaction survey). IT plays an important role in increasing airport performance through the automation of processes such as the deployment of common-use check-in desks and self-service check-in kiosks. Studies of other industries have shown evidence that IT impacts firm performance, but there have been few studies related to the airport industry. Thus, the aim of this research is to assess the relationship between IT and airport performance, and it proposes a conceptual framework to assess the relationship between IT and airport performance by drawing from studies in other industries. Two methodologies were used in this research, the first one was the case study, and the second one was the online survey. The case studies consisted of 16 faceto- face interviews with senior staff representing two airports in Asia, one airport in Australia, and one airport in Europe. The case studies result show that there is a relationship between IT and airport performance ... [cont.]

    Aviation Biofuel Production in Sweden

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    Civil Aviation is one of the fastest growing sectors on earth, for which emissions currently account for between 2 and 3% of the global total (International Air Transport Association, 2013). Decarbonising the aviation sector is a key challenge on the international agenda, for which sustainable alternative fuels stand as playing a future role. Biofuels for aviation (biojet) have shown to be energy efficient, safe and generate significant emissions savings (Faaij & van dijk, 2012). Efforts are currently underway to accelerate biojet fuel development through establishing global and regional supply chains for commercial production, yet high production costs, relative to fossil based fuel production stands as the fundamental hurdle preventing commercial scale production. The Nordic region is characterised as having good potential for biofuel production, prompting studies throughout Norway, Finland and Denmark. Similar environmental conditions are found within Sweden, yet a Swedish regional investigation into biojet production opportunities is yet to be carried out. This research identifies key opportunities and barriers to establishing a biojet production system within Sweden using available forestry biomass as a feedstock. Findings indicate that the availability of forestry biomass resources, infrastructure and knowledge present within the Swedish system could support the establishment of a biojet system, yet high production costs and a lack of policy support create unfavourable market conditions. Future efforts to establish biojet uptake in Sweden may include lobbying for policy change at the national level to recognize aviation emissions when setting policy targets. The process of facilitating collaboration through linking actors in the field, both within Sweden and throughout the wider Nordic region, is an essential non-technical component to streamline future potential supply chain pathways

    Wageningen University and Research centre : Your partner for sustainable development in the Arctic

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    This position paper explores new claims in the Arctic region. These claims are closely connected to new developments in the region such as climate change and the utilisation of natural resources. The aim of the paper is to illustrate how Wageningen University and Research centre contributes to sustainable development in the Arctic

    An investigation of change in drone practices in broadacre farming environments

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    The application of drones in broadacre farming is influenced by novel and emergent factors. Drone technology is subject to legal, financial, social, and technical constraints that affect the Agri-tech sector. This research showed that emerging improvements to drone technology influence the analysis of precision data resulting in disparate and asymmetrically flawed Ag-tech outputs. The novelty of this thesis is that it examines the changes in drone technology through the lens of entropic decay. It considers the planning and controlling of an organisation’s resources to minimise harmful effects through systems change. The rapid advances in drone technology have outpaced the systematic approaches that precision agriculture insists is the backbone of reliable ongoing decision-making. Different models and brands take data from different heights, at different times of the day, and with flight of differing velocities. Drone data is in a state of decay, no longer equally comparable to past years’ harvest and crop data and are now mixed into a blended environment of brand-specific variations in height, image resolution, air speed, and optics. This thesis investigates the problem of the rapid emergence of image-capture technology in drones and the corresponding shift away from the established measurements and comparisons used in precision agriculture. New capabilities are applied in an ad hoc manner as different features are rushed to market. At the same time existing practices are subtly changed to suit individual technology capability. The result is a loose collection of technically superior drone imagery, with a corresponding mismatch of year-to-year agricultural data. The challenge is to understand and identify the difference between uniformly accepted technological advance, and market-driven changes that demonstrate entropic decay. The goal of this research is to identify best practice approaches for UAV deployment for broadacre farming. This study investigated the benefits of a range of characteristics to optimise data collection technologies. It identified widespread discrepancies demonstrating broadening decay on precision agriculture and productivity. The pace of drone development is so rapidly different from mainstream agricultural practices that the once reliable reliance upon yearly crop data no longer shares statistically comparable metrics. Whilst farmers have relied upon decades of satellite data that has used the same optics, time of day and flight paths for many years, the innovations that drive increasingly smarter drone technologies are also highly problematic since they render each successive past year’s crop metrics as outdated in terms of sophistication, detail, and accuracy. In five years, the standardised height for recording crop data has changed four times. New innovations, coupled with new rules and regulations have altered the once reliable practice of recording crop data. In addition, the cost of entry in adopting new drone technology is sufficiently varied that agriculturalists are acquiring multiple versions of different drone UAVs with variable camera and sensor settings, and vastly different approaches in terms of flight records, data management, and recorded indices. Without addressing this problem, the true benefits of optimization through machine learning are prevented from improving harvest outcomes for broadacre farming. The key findings of this research reveal a complex, constantly morphing environment that is seeking to build digital trust and reliability in an evolving global market in the face of rapidly changing technology, regulations, standards, networks, and knowledge. The once reliable discipline of precision agriculture is now a fractured melting pot of “first to market” innovations and highly competitive sellers. The future of drone technology is destined for further uncertainty as it struggles to establish a level of maturity that can return broadacre farming to consistent global outcomes

    Aeronautical engineering: A continuing bibliography with indexes (supplement 322)

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    This bibliography lists 719 reports, articles, and other documents introduced into the NASA scientific and technical information system in Oct. 1995. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

    Advanced meta-heuristic approaches and their application to operational optimization in forest wildfire management

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    La última década ha sido testigo de un aumento vertiginoso de la cantidad y frecuencia de desastres a gran escala, principalmente debido a los fenómenos devastadores derivados de paradigmas climatológicos y ambientales a gran escala como el calentamiento global. De entre ellos son las inundaciones, huracanes y terremotos los desastres de mayor frecuencia de aparición y fatales consecuencias durante este período, tal como certifican los más de 20.000 muertos a consecuencia de un terremoto en la región de Gujarat (India) en 2001, o las 230.000 y 316.000 pérdidas humanas de los terremotos de Indonesia y Haití en 2004 y 2010, respectivamente. En este contexto, el enfoque de esta tesis se centra en una casuística concreta de desastre a media-gran escala cuya frecuencia y severidad han crecido de manera igualmente preocupante en los últimos tiempos: los incendios, definidos como un fuego de grandes dimensiones no voluntariamente iniciado por el ser humano, y que afecta a aquello que no está destinado a quemarse. Pese a la diversidad de iniciativas, campañas y procedimientos orientados a la minimización del impacto y las consecuencias de los incendios, varios sucesos fatales acontecidos en los últimos años han puesto en duda la efectividad de las políticas actuales de gestión de recursos contra incendios como aeronaves, vehículos terrestres, equipamiento de comunicaciones radio, logística de abastecimiento y las brigadas desplegadas en el área afectada. Un ejemplo manifiesto de esta falta de eficacia es la muerte de once bomberos ocurrida en un incendio de 130 kilómetros cuadrados en la zona de Guadalajara (España) en 2005, oficialmente atribuida a una deficiente coordinación entre el puesto de mando y los equipos de extinción debida, fundamentalmente, a problemas de cobertura en los sistemas de radiocomunicación. Aunque la causa de esta falta de coordinación ha sido cuestionada por las autoridades y los agentes involucrados desde entonces, lo cierto es que este suceso supone un ejemplo evidente de la necesidad de estudiar y desarrollar herramientas algorítmicas que ayuden al personal de comandancia a ejecutar óptimamente sus tareas de coordinación y control. Desafortunadamente la coyuntura de crisis económica mundial que azota con especial fuerza los países del Sur de Europa ha mermado dramáticamente las partidas presupuestarias para la prevención y extinción de incendios en beneficio de programas nacionales de reducción de déficit. A consecuencia de estos recortes, el coste ha irrumpido con fuerza como un criterio de extrema relevancia en la planificación operativa de este tipo de desastres: desde la perspectiva de un problema de optimización, los recursos contra incendios son actualmente gestionados con el objetivo fundamental de maximizar su efectividad contra incendios, sujeto a la restricción de que el coste agregado asociado a las decisiones tomadas no supere un determinado umbral presupuestario. Pese a que estas restricciones de coste están bien acotadas, en la práctica la mayoría de los procedimientos de gestión de recursos contra incendios están fuertemente determinados por la capacidad limitada del ser humano para tomar decisiones ágiles en escenarios de elevada complejidad y heterogeneidad. Por los motivos anteriormente expuestos, la presente Tesis doctoral propone la adopción de algoritmos meta-heurísticos para solventar eficientemente problemas de optimización que modelan procesos de gestión de recursos contra incendios. Esta familia de algoritmos de optimización es capaz de explorar el espacio solución de un problema dado merced a la aplicación iterativa de mecanismos inteligentes de búsqueda explorativa y explotativa, produciendo soluciones que sacrifican calidad por una complejidad computacional menor en comparación con la resultante de procesos determinísticos de búsqueda exhaustiva. En particular la Tesis plantea la búsqueda por harmonía (del inglés Harmony Search) como la técnica meta-heurística de optimización común a las herramientas diseñadas para la gestión de recursos en dos escenarios diferentes: ? El primer escenario analizado contempla el despliegue óptimo de redes de comunicación inalámbrica para la coordinación de equipos de extinción en incendios forestales de gran escala. Desde el punto de vista formal, el problema del despliegue dinámico de retransmisores que caracteriza matemáticamente este escenario consiste en estimar el número y localización de los retransmisores radio que deben ser desplegados en el área afectada por el incendio, de tal modo que el número de nodos móviles (i.e. recursos) con cobertura radio es maximizado a un coste del despliegue mínimo. A fin de reflejar la diversidad de equipamiento de retransmisión radio existente en la realidad, este problema es reformulado para considerar modelos de retransmisor con diferentes características de cobertura y coste. El problema resultante es resuelto de manera eficiente mediante sendos algoritmos mono- y bi-objetivo que conjugan 1) la Búsqueda por Harmonía como método de búsqueda global; y 2) una versión modificada del algoritmo de agrupación K-means como técnica de búsqueda local. El desempeño de los métodos propuestos es evaluado mediante experimentos numéricos basados en datos estadísticos reales de la Comunidad de Castilla la Mancha (España), merced a cuyos resultados queda certificada su practicidad a la hora de desplegar infraestructura de comunicación en este tipo de desastres. ? El segundo escenario bajo estudio se concentra en el despliegue y planificación óptima de vehículos aéreos de extinción de incendios basados en estimaciones predictivas del riesgo de incendio de una cierta área geográfica. De manera enunciativa, el problema subyacente busca la asignación de recursos a aeródromos y aeropuertos con restricciones de capacidad que maximice la utilidad de dichos recursos en relación al riesgo de incendio y minimice, a su vez, el coste de ejecutar dicha asignación. La formulación de este problema también considera, dentro de la definición de dicha función de utilidad, la distancia relativa entre aeropuerto, punto de potencial riesgo de incendio y el recurso acuífero (lago, río o mar) más cercano. Para su resolución eficiente se propone el uso de algoritmos de optimización basados, de nuevo, en la Búsqueda por Harmonía, incorporando además métodos voraces de reparación capacitiva. La aplicabilidad práctica de estos métodos es validada mediante experimentos numéricos en escenarios sintéticos y un caso práctico que incluye valores reales del riesgo de incendio, posiciones de recursos acuíferos e instalaciones aeroportuarias. En resumen, esta Tesis evidencia, desde un punto de vista práctico, que la meta-heurística moderna supone una solución algorítmica computacionalmente eficiente para tratar problemas de gestión de recursos contra incendios sujetos a restricciones de coste

    System elements required to guarantee the reliability, availability and integrity of decision-making information in a complex airborne autonomous system

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    Current air traffic management systems are centred on piloted aircraft, in which all the main decisions are made by humans. In the world of autonomous vehicles, there will be a driving need for decisions to be made by the system rather than by humans due to the benefits of more automation such as reducing the likelihood of human error, handling more air traffic in national airspace safely, providing prior warnings of potential conflicts etc. The system will have to decide on courses of action that will have highly safety critical consequences. One way to ensure these decisions are robust is to guarantee that the information being used for the decision is valid and of very high integrity. [Continues.
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