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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.
31

The eagle and the albatross : Australian aerial maritime operations 1921-1971

Wilson, David Joseph, Humanities & Social Sciences, Australian Defence Force Academy, UNSW January 2003 (has links)
The aim of this thesis is to examine the relationship between the Royal Australian Air Force (RAAF) and the Royal Australian Navy (RAN) regarding the operation of aircraft from ships of the RAN and from RAAF shore bases. The effects of the separate intellectual development of maritime doctrine in the RAAF and RAN, and the efforts of the two Australian services to transfer theory into practice will be considered in the pre- (and post) World War II period, with due consideration of the experience of the services in both wars. The thesis will also discuss the problems that were faced by the RAAF and RAN to develop mutually acceptable operational procedures to enable the efficient use of aircraft in a maritime setting. The influence and effect on RAAF and RAN doctrine and equipment procurement, as a result of the special relationships that developed between the Air Force and Navy of Australia and Britain will be critically examined. A similar approach to the post war US/Australian relationship, and its effect on the Australian services, will also be critically examined. The thesis being propounded is that the development of a unique Australian maritime policy was retarded due to a combination of the relationship with Britain and the United States, lack of suitable equipment, lack of clear operational concepts in both the RAAF and RAN and the parochial attitude of the most senior commanders of both Services. The study has been based on Department of Navy, Department of Air and Department of Defence documents held in the National Archives of Australia in Canberra and Melbourne. In addition, relevant documents from the Admiralty and Air Ministry related to the development of naval aviation on RAN vessels during World War I, the attitude of the RAF toward the deployment of RAAF units to Singapore, and the negotiations that resulted in the procurement of HMA Ships Sydney and Melbourne, have been perused. Wartime operational records of the RAAF have been examined to obtain data to enable a critical study to be made of the RAAF anti-submarine campaign, torpedo bomber operations and the maritime campaign undertaken from bases in North Western Area during World War II. The influence of the commander of the United States 5th Air Force has also been incorporated in the discussion. The research uncovered procedural and operational variations between the two Services, the diversion of key elements from Australian command and the priority given to the American line of advance that resulted in Australian operations being given a secondary, supportive, status. A conclusion reached as a result of this research has been that the development of a unique Australian maritime aerial capability was restricted by the requirement of Britain to deploy flying units to Singapore in 1940. Similarly, the pressure exerted on the RAN by the Admiralty to purchase the Light Fleet Carriers in the late 1940s was more in the interests of the RN and British foreign policy than that of the RAN. Overall, the relationship with the Britain and the United States masked the real weakness in Australia???s maritime operations and retarded its development.
32

Instance Segmentation of Multiclass Litter and Imbalanced Dataset Handling : A Deep Learning Model Comparison / Instanssegmentering av kategoriserat skräp samt hantering av obalanserat dataset

Sievert, Rolf January 2021 (has links)
Instance segmentation has a great potential for improving the current state of littering by autonomously detecting and segmenting different categories of litter. With this information, litter could, for example, be geotagged to aid litter pickers or to give precise locational information to unmanned vehicles for autonomous litter collection. Land-based litter instance segmentation is a relatively unexplored field, and this study aims to give a comparison of the instance segmentation models Mask R-CNN and DetectoRS using the multiclass litter dataset called Trash Annotations in Context (TACO) in conjunction with the Common Objects in Context precision and recall scores. TACO is an imbalanced dataset, and therefore imbalanced data-handling is addressed, exercising a second-order relation iterative stratified split, and additionally oversampling when training Mask R-CNN. Mask R-CNN without oversampling resulted in a segmentation of 0.127 mAP, and with oversampling 0.163 mAP. DetectoRS achieved 0.167 segmentation mAP, and improves the segmentation mAP of small objects most noticeably, with a factor of at least 2, which is important within the litter domain since small objects such as cigarettes are overrepresented. In contrast, oversampling with Mask R-CNN does not seem to improve the general precision of small and medium objects, but only improves the detection of large objects. It is concluded that DetectoRS improves results compared to Mask R-CNN, as well does oversampling. However, using a dataset that cannot have an all-class representation for train, validation, and test splits, together with an iterative stratification that does not guarantee all-class representations, makes it hard for future works to do exact comparisons to this study. Results are therefore approximate considering using all categories since 12 categories are missing from the test set, where 4 of those were impossible to split into train, validation, and test set. Further image collection and annotation to mitigate the imbalance would most noticeably improve results since results depend on class-averaged values. Doing oversampling with DetectoRS would also help improve results. There is also the option to combine the two datasets TACO and MJU-Waste to enforce training of more categories.
33

La lutte contre la pollution marine en France / Prevention and control of marine pollution in France

Pantelodimou, Eirini 09 December 2013 (has links)
La mer joue un rôle essentiel dans la régulation du climat et dans l'équilibre écologique. Les océans et les mers constituent une source de richesse, un immense réservoir de ressources alimentaires et d'emplois pour un grand nombre de personnes. La mer Méditerranée est un écosystème sensible soumis à de fortes pressions par les activités humaines comme la pêche, l'exploration gazière et pétrolière, l'immersion des déchets ou d'autres matières en mer, le transport maritime, le transfert d'espèces aquatiques envahissantes par les eaux de ballast et le tourisme littoral. La France durement touchée par les naufrages de l'Amoco Cadiz, de l'Erika et du Prestige, a pris de nombreuses initiatives tant au niveau international que régional. La complexité du problème de la pollution marine, due à la diversité des facteurs polluants et à leurs sources diffuses, a favorisé une approche sectorielle. Cette approche s'est traduite par l'adoption, aux niveaux national, régional et international, d'un ensemble disparate de politiques, textes législatifs, programmes et plans d'action dans le domaine de la protection du milieu marin. Il s'agit d'un corps de règles étouffées comprenant des mesures préventives et répressives. La complexité institutionnelle et juridique de la protection du milieu marin empêche pourtant la protection effective de la mer. Dans ce contexte, la communauté internationale encourage la mise en œuvre d'une approche écosystématique pour les océans. À l'échelle européenne, l'adoption de la directive-cadre « stratégie pour le milieu marin » favorise la cohérence entre les différentes politiques européennes et l'intégration des préoccupations environnementales dans toutes les politiques liées à la mer. De plus, l'efficacité de la législation européenne dans le domaine de la lutte contre la pollution marine a été renforcée par l'adoption d'un cadre commun de responsabilité pour la prévention et la réparation des préjudices environnementaux. / The sea plays a vital role in regulating climate and in maintaining ecological balance. The oceans and the sea constitute a source of wealth, an immense reservoir of food resources and of employment for many people. The Mediterranean Sea is a sensitive ecosystem, subject to strong pressures derived from human activities, such as fishing, oil and gas exploration, dumping of waste and other matter in the sea, maritime transport, transfer of aquatic invasive species via ballast water and littoral tourism. France, severely affected by the sinking of the Amoco Cadiz, the Erika and the Prestige, took numerous initiatives not only at an international but also at a regional level. The complexity of the marine pollution problem, due to the diversity of polluting factors and to their diffuse sources, has favored a regional approach. This approach has resulted in the adoption, at a national, regional and international level, of a network of policies, legislative texts, programs and action plans in the field of marine environment protection. It constitutes a stifling body of rules, comprising preventive and repressive measures. The institutional and legal complexity of marine protection hinders, however, the effective protection of the marine environment. ln this context, the international community encourages the implementation of an ecosystem approach to oceans. At European level, the adoption of the Framework Directive «Strategy for the Marine Environment» favours a consistency between different EU policies as well as an integration of environmental considerations into ail policies related to the sea. Furthermore, the effectiveness of European legislation in the field of the fight again marine pollution, has been reinforced by the adoption of a common framework of liability with regard to the prevention and remedy of environment damage.

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