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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Knowledge-Based Engineering Application For Fuselage Integration And Cabin Design

Bhargav, Nikhil, Elangovan, Vasanth January 2023 (has links)
The pace of development in aviation technology is increasing, and there is a constantneed for new concepts to keep up. An innovative concept is desired to reach the netzero emission and sustainability target visualized in Flight path 2050. Introducing digital models and virtualization into aviation fields reduces time consumption onmanual modelling and increases design accuracy. Digital mock-up models also helpin minimizing costs due to errors in the later stage of development or manufacturing. The Institute of Systems Architecture in Aeronautics at German AerospaceCenter (DLR) works in digitizing cabin design environments with extensive implementation of the Knowledge-Based Engineering (KBE) approach. The virtual cabindesign system tool also known as Fuselage Geometry Assembler (FUGA) providesa digital model of the cabin of both single and twin aisle configurations of commercial aircraft. The information of aircraft characteristics is provided to FUGA using Common Parametric Aircraft Configuration Schema (CPACS). CPACS coupled with FUGA provides the user with a consistent model of aircraft and cabindesign, when viewed through a virtual platform provides an immersive experienceto be inside an aircraft cabin before physical production. The multidisciplinary capability of FUGA provides experts from different disciplines to perform analysis such as vibration analysis on the cabin environment. For ease of usage and better visualization of information from FUGA, a web-based application through Flask is hosted for FUGA. This enables the user to access the FUGA tool without the needof installing the tool on their devices. With the world now moving towards a greener approach, an alternative propulsion system may require a different fuel tank configuration. Retro-fit of liquid hydrogen fuel tank into an existing aircraft’s fuselage is done using FUGA tool and aircraft performance analysis is conducted and the outcomes are studied. The enhanced and advanced model of twin-aisle configuration, now on par with single-aisle configuration is used for hydrogen tank sensitivity analysis. The comparative study of different aisle configurations retro-fitted with liquidhydrogen fuel tank is further conducted for arriving at an optimal design point fora balance in range and passenger capacity.
12

Optimized Escape Path Planning for Commercial Aircraft Formations

Saber, Safa I. 07 1900 (has links)
There is growing interest in commercial aircraft formation flight as a means of reducing both airspace congestion and the carbon footprint of air transportation. Wake vortex surfing has been researched extensively and proven to have significant fuel-saving benefits, however, commercial air transportation has yet to take advantage of these formation benefits due to understandable safety concerns. The realization of these formations requires serious consideration of formation contingencies and safety during closer-in maneuvering of large commercial aircraft. Formation contingency scenarios are much more complex than those of individual aircraft and have not yet been studied in depth. This thesis investigates the utility of optimization modeling in providing insight into generation of aircraft escape paths for formation contingency planning. Three high-altitude commercial aircraft formation scenarios are presented; formation join, formation emergency exit, and formation escape. The model-generated paths are compared with pilot-generated escape plans using the author’s pilot expertise. The model results compare well with pilot intuition and are useful in presenting solutions not previously considered, in evaluating separation requirements for improvement of escape path planning and in confirming the viability of the pilot-generated plans. The novel optimization model formulation presented in this thesis is the first model shown to be capable of generating escape paths comparable to pilot- generated escape plans and is also the first to incorporate avoidance of persistent and drifting wake turbulence within the formation.
13

Excess Baggage: Weighing the Contribution of Political and Corporate Interests in the W.T.O. Cases over Commercial Aircraft Subsidies

Spadafore, Annemarie Michaela 15 August 2008 (has links)
No description available.
14

Mitigating the MANPADS threat: international agency, U.S., and Russian efforts / Mitigating the Manned Portable Air Defense Systems threat

Bartak, John R. 03 1900 (has links)
Approved for public release, distribution is unlimited / There are in excess of 500,000 Manned Portable Air Defense Systems (MANPADS) in worldwide inventories including several thousand outside of government control. MANPADS are surface-to-air missile systems enabling the operator to launch missiles at aircraft from the ground. The most common MANPADS are the Russian SA-7 and U.S. Stinger, which feature infrared guidance systems. The concern that MANPADS can easily be acquired by non-state actors' intent on downing civilian and military aircraft has led international agencies, the U.S., and Russia to implement measures to reduce the risk of a MANPADS attack. International agencies such as the Wassenaar Arrangement work to stop illegal MANPADS proliferation. The U.S. MANPADS Defense Act and the U.S. Department of Homeland Security have implemented measures to counter the MANPADS threat. Russia has revised its export controls and forged a counter-proliferation agreement with most CIS countries. However, the multilateral initiatives to better control MANPADS stocks and transfers are far from comprehensive. A new approach to mitigating the MANPADS threat adopts elements from the 1997 Mine Ban Treaty and the Landmine Monitor. The conclusion of this thesis is that if MANPADS counter-proliferation efforts remain status quo an attack on a commercial aircraft in the western world is imminent.
15

Excess baggage weighing the contribution of political and corporate interests in the W.T.O. cases over commercial aircraft subsidies /

Spadafore, Annemarie Michaela. January 2008 (has links)
Thesis (Ph. D.)--Miami University, Dept. of Political Science, 2008. / Title from first page of PDF document. Includes bibliographical references (p.112-118).
16

Réseaux de collecte de données pour les zones blanches étendues / Data collection networks for wide white areas

Adamou, Djibrilla Incha 29 November 2019 (has links)
Les zones blanches étendues sont de vastes espaces géographiques (forêts, déserts), sans ou ayant très peu d’infrastructures telles que les routes, les réseaux électriques ou de télécommunication. Cependant, très souvent, dans ces zones se développent de nombreuses activités économiques ou environnementales telles que le monitoring de l’environnement, la surveillance d’une frontière ou d’une installation de pipeline, ou encore la prévention des feux de forêt. Grâce aux techniques de télédétection et de communication, une fonction clé de ces activités repose sur la collecte d’informations issues de capteurs qui sont transmises à un centre d’analyse distant. Nous proposons des solutions réseau afin d’effectuer la collecte de ces données dans les zones blanches étendues grâce à des technologies de communication longue distance et faible énergie, de type LoRaWAN. Pour le problème du déploiement du réseau de capteurs sans fil dans ces zones difficiles, nous avons proposé une heuristique inspirée de la croissance biologique d’un champignon, le physarum. Le physarum est capable de créer un corps complexe de liens pour trouver de la nourriture nécessaire à sa survie tout en optimisant ses propres ressources corporelles lors des périodes de disette. Ce principe d’optimisation a été adapté au domaine des réseaux pour déployer un réseau tolérant aux fautes, tout en minimisant le nombre de ressources ou relais à placer sur la zone d’intérêt. Nous nous sommes ensuite intéressés à la collecte opportuniste de données dans les zones blanches afin de pouvoir collecter l’information des nœuds trop éloignés d’une station relais. Nous avons développé une méthode de collecte basée sur les avions de ligne qui survole le territoire. Durant une fenêtre de communication, l’avion est à portée d’un capteur et peut ainsi collecter les données stockées qui seront livrées au serveur à l’atterrissage de l’avion. Notre dernière contribution utilise conjointement les deux méthodes précédentes, pour permettre à la fois le déploiement du réseau et la collecte des capteurs isolés. / Although wide white areas are not equipped or sparsely equipped with any infrastructure (energy, roads ...), strategic human activities are being carried out such as mines, forest, pipeline... To tackle the problem of deploying sensor networks in a very large area where few infrastructures are available, we propose a network deployment algorithm which aims at efficiently linking sparse points of interest in a very wide white area. The originality of the proposed method is that it mimics the evolution of a type of mold called physarum. Secondly, we aim at overcoming the deployment problem in wide white areas by using long range communication between an aircraft and earth. The new data collection scheme he proposes is based on the use of commercial flights to collect data while they cross over an area of interest. It investigates the feasibility of such a scheme by determining the collection capacity of commercial aircraft in different locations of the desert. Finally, we mixed both solutions do repatriate data from sensors not covered by any flight to a covered data sink that relays data to the aircraft.
17

Improving Aircraft Fuel Consumption Prediction through Ensemble Learning / Förbättrande av bränsleförbrukningsestimering genom ensembleinlärning

Gongzhang, Hanlin January 2022 (has links)
Performance models provided by aircraft manufacturers are used by aircraft operators to perform flight path simulations aiming to reduce aircraft fuel consumption. However, performance models are generic and does not account for the performance deviations of each aircraft individual. The performance deviations, particularly in terms of fuel consumption, will affect the dynamic programming of flight path simulations. This may result in a less optimal flight path and ultimately lead to higher fuel consumption than expected. In hope of reducing this risk, a collection of local performance factors were derived. These factors describe the percentual deviation between the real fuel flow and the levels predicted by the performance model, and are allocated with respect to a range of flight parameters in a data library known as the performance library. A test environment is then constructed to simulate a continuous flow of flight data, where a new performance library is derived from the flight data of every month. The local performance factors of the previous month are then updated with the current; a learning process based on the weighted average ensemble approach. Further, the local performance factors are used in conjunction with the performance model to estimate the aircraft fuel consumption during cruise. The observed average prediction error is noticeably smaller than that of an equivalent global, scalar performance factor used by airlines today. The result also reveals that the prediction accuracy and versatility of the performance library is mainly determined by its resolution - higher resolution generally offers better accuracy at a cost of requiring more flight data, whereas lower resolutions are more versatile but of lower accuracy. Finally, the performance libraries of two identical aircraft are used to trace the performance deviation between them. The weighted average of all local performance factors in the performance library of respective aircraft reveal that the average fuel consumption is roughly -1.9 % and -2.5 % lower than the estimates by the performance model, ultimately proving that it is feasible to detect overall fuel efficiency deviation between two identical aircraft. / Prestandamodeller tillhandhållna av flygplanstillverkarna används oftast av flygbolagen för att utföra flygruttsimuleringar i syfte att bespara bränsle. Dock är prestandamodellerna generiska och tillgodoräknar inte prestandaavvikelserna som förekommer hos varje flygplansindivid. Dessa prestandaavvikelser, speciellt i form av bränsleförbrukning, kommer att påverka den dynamiska programmeringen i flygruttssimulationen. Följde när flygrutter som kan leda till högre förbrukningar än de ursprungligen uppskattades. I hopp om att minimera denna risk beräknades mängder av lokala prestandafaktorer, vilka grundar på prestandamodellens avvikelse från verkliga flygdata. Dessa koefficienter allokerades sedan till ett databibliotek (prestandabibliotek) med avseende på en samling av flygparametrar. En testmiljö konstruerades i följd för att simulera ett kontinuerligt dataflöde. Vidare skapades ett prestandabibliotek för varje månadsflygdata, där de nyskapade lokala prestandafaktorerna viktas med de motsvarandeparterna i föregående månadens prestandabibliotek, vilket är en inlärningsprocessbaserad på viktad medelvärdesensemble. Prestandabiblioteket applicerades sedan över prestandamodellen och det snittliga uppskattning felet observerades vara märkbart mindre än det från en motsvarande global, skalärbaserad prestandafaktor. Resultatet antyder också på att prestandabibliotekets uppskattningsnoggrannhet och allsidighet beror huvudsakligen på dess upplösning - en hög upplösning leder generellt till ökad uppskattningsnoggrannhet med på bekostnad av mer flygdata, medan lägre upplösningar tenderar att vara mer allsidiga men med mindre uppskattningsnoggrannhet. Slutligen användes prestandabiblioteken av två identiska flygplan för att spåra prestandaavvikelser som förekommer mellan dem. Viktat medelvärde av alla prestandafaktorer i respektiveflygplanets prestandabibliotek tyder på att snittförbrukningen är ungefär 1,9 % respektive2,5 % lägre än det som uppskattades av prestandamodellen. Härmed bevisades att det är möjligt att spåra varianser i snittförbrukningen mellan två identiska flygplan.

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