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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.
1

Evaluation of night vision devices for image fusion studies

Cheng, Wee Kiang 12 1900 (has links)
Approved for public release; distribution in unlimited. / Night Vision Devices (NVD) using Image Intensification (II) technology are among the most important sensors used by ground troops and aviators in night operations for modern combat. With the intensified images from these devices, soldiers can see an enemy's movement better and further in darkness. This thesis explores different test methods in evaluating the performances and sensitivities of several NVDs for future image fusion studies. Specification data such as sensitivity, resolution (Modulation Transfer Function) and pixel size are obtained. Comparative analyses of the collected results are made to characterize the performances of the different NVDs. A new method using MATLAB programming to objectively analyze digitized images for characterization of II based NVDs is proposed. This test method can also be extended to the evaluation of Thermal Imaging (TI) systems for comparative analysis with II NVDs. In addition, the feasibility of testing NVDs using both II and TI technologies, with common operating conditions and target boards is discussed. Finally, the potential of using these digitized images for image fusion studies is verified with the test and evaluation results. / Republic of Singapore
2

Towards sustainable tourism in outback Australia: the behaviour and impact of nature-based tourists on vegetation and selected wildlife species

Wolf, Isabelle Diana Felicitas Gudula, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2009 (has links)
Nature-based tourism offers significant socio-economic incentives to successfully replace more intrusive land uses but also causes negative environmental impacts. Currently, knowledge is needed about the effectiveness of specific management actions such as the provision of different access modes and tour experiences at minimizing these impacts while maximizing visitor satisfaction. Nature-based tourism activities were studied in the species-rich gorges of the Flinders Ranges in Outback Australia. This study developed a conceptual framework of visitor-environment relationships, constructed a regional visitor profile, assessed visitor monitoring methods to quantify usage intensity in relation to the access mode (roads vs. hiking trails), examined changes in vegetation and bird communities in relation to usage intensity and access mode, tested effects of approach behaviour among driving vs. hiking tourists on kangaroo behaviour, and designed a framework for a night-time wildlife tour. The usage intensity of gorge sections was best determined from visitor numbers stratified by their behaviour, as the access mode fundamentally changed visitor behaviour in gorges. High compared to low usage recreational tracks altered species community composition, decreased total plant cover, increased non-native species cover, increased or decreased plant diversity depending on the track distance, increased soil compaction, and decreased bird numbers and species richness. Vegetation changes had secondary aversive effects on the bird community. The magnitude and spatial extent of these community impacts were greater along roads than trails. Visitor approach towards kangaroos varied with the access mode and necessitated individual recommendations for low-impact behaviour. The optimal night-time observation tour employed night-vision devices and bat detectors and coupled visitor satisfaction with low impact on wildlife. A range of factors (e.g., weather conditions) moderated the susceptibility of the wildlife to tourism disturbance. To protect wildlife and habitat along recreational tracks in arid-lands gorges, it is recommended to (1) monitor usage intensity and the identified impact indicators within their effect zone, (2) curtail gorge usage by restricting vehicle access to sections and regulating high impact activities (e.g., wild camping), (3) base environmental education upon scientifically tested low-impact visitor behaviour, and (4) engage with tourism operators in the design of low-impact, yet satisfying tours based on scientific principles.

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