1,752 research outputs found

    Towards 3D Matching of Point Clouds Derived from Oblique and Nadir Airborne Imagery

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    Because of the low-expense high-efficient image collection process and the rich 3D and texture information presented in the images, a combined use of 2D airborne nadir and oblique images to reconstruct 3D geometric scene has a promising market for future commercial usage like urban planning or first responders. The methodology introduced in this thesis provides a feasible way towards fully automated 3D city modeling from oblique and nadir airborne imagery. In this thesis, the difficulty of matching 2D images with large disparity is avoided by grouping the images first and applying the 3D registration afterward. The procedure starts with the extraction of point clouds using a modified version of the RIT 3D Extraction Workflow. Then the point clouds are refined by noise removal and surface smoothing processes. Since the point clouds extracted from different image groups use independent coordinate systems, there are translation, rotation and scale differences existing. To figure out these differences, 3D keypoints and their features are extracted. For each pair of point clouds, an initial alignment and a more accurate registration are applied in succession. The final transform matrix presents the parameters describing the translation, rotation and scale requirements. The methodology presented in the thesis has been shown to behave well for test data. The robustness of this method is discussed by adding artificial noise to the test data. For Pictometry oblique aerial imagery, the initial alignment provides a rough alignment result, which contains a larger offset compared to that of test data because of the low quality of the point clouds themselves, but it can be further refined through the final optimization. The accuracy of the final registration result is evaluated by comparing it to the result obtained from manual selection of matched points. Using the method introduced, point clouds extracted from different image groups could be combined with each other to build a more complete point cloud, or be used as a complement to existing point clouds extracted from other sources. This research will both improve the state of the art of 3D city modeling and inspire new ideas in related fields

    Fast, scalable, Bayesian spike identification for multi-electrode arrays

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    We present an algorithm to identify individual neural spikes observed on high-density multi-electrode arrays (MEAs). Our method can distinguish large numbers of distinct neural units, even when spikes overlap, and accounts for intrinsic variability of spikes from each unit. As MEAs grow larger, it is important to find spike-identification methods that are scalable, that is, the computational cost of spike fitting should scale well with the number of units observed. Our algorithm accomplishes this goal, and is fast, because it exploits the spatial locality of each unit and the basic biophysics of extracellular signal propagation. Human intervention is minimized and streamlined via a graphical interface. We illustrate our method on data from a mammalian retina preparation and document its performance on simulated data consisting of spikes added to experimentally measured background noise. The algorithm is highly accurate

    QUEST Hierarchy for Hyperspectral Face Recognition

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    Face recognition is an attractive biometric due to the ease in which photographs of the human face can be acquired and processed. The non-intrusive ability of many surveillance systems permits face recognition applications to be used in a myriad of environments. Despite decades of impressive research in this area, face recognition still struggles with variations in illumination, pose and expression not to mention the larger challenge of willful circumvention. The integration of supporting contextual information in a fusion hierarchy known as QUalia Exploitation of Sensor Technology (QUEST) is a novel approach for hyperspectral face recognition that results in performance advantages and a robustness not seen in leading face recognition methodologies. This research demonstrates a method for the exploitation of hyperspectral imagery and the intelligent processing of contextual layers of spatial, spectral, and temporal information. This approach illustrates the benefit of integrating spatial and spectral domains of imagery for the automatic extraction and integration of novel soft features (biometric). The establishment of the QUEST methodology for face recognition results in an engineering advantage in both performance and efficiency compared to leading and classical face recognition techniques. An interactive environment for the testing and expansion of this recognition framework is also provided

    Acculturation as a Mediating Factor between Ethnic and Self-Identities

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    Is acculturation a mediating factor in self- and ethnic identity among ethnic minority emerging-adults? A conceptual model was tested examining links between self and ethnic identity and acculturation. An association was proposed between perceived social support, affirmation and belonging, and EOM self-identity statuses (diffusion, foreclosure, moratorium, achievement) as mediated by VIA mainstream and heritage acculturation. A second association was proposed between out-group orientation, interpersonal variables, and ethnic identity as mediated by VIA mainstream and heritage acculturation. This study did not provide full support for acculturation as a mediating variable; rather, the ‘interpersonal variable’ was an intervening variable in the association between heritage acculturation and ethnic identity search and affirmation and belongingness. The results confirm that VIA mainstream acculturation is not mediating an effect on ethnic identity; rather, it has a direct effect. The results also confirm that the interpersonal variable is not mediating an effect on ethnic identity. Implications and directions for future research are discussed

    Correlational Study of Embezzlement and Economic Conditions in New England

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    This research study was conducted to contribute to the body of knowledge related to embezzlement, a classification of occupational fraud. According to the Association of Certified Fraud Examiners (ACFE, 2020), it is estimated that losses from occupational fraud represent 5% of revenue each year and that 86% of occupational fraud included asset misappropriation or embezzlement. The purpose of this quantitative research study was to investigate the relationship between economic indicators and incidents of embezzlement. The study population included all incidents of embezzlement reported in New England between 2004 and 2018. Archival data were collected from various governmental sources for both the embezzlement incidents and the economic indicators. The data analysis process included statistical analysis of the data over time, known as time-series analysis. The statistical analysis indicated that economic indicators do not help predict incidents of embezzlement. The findings of this study may impact the way organizational leaders and accounting professionals assess risk related to embezzlement. Vigilance of fraud risk, regardless of economic conditions, may help organizational leaders protect against losses from embezzlement

    Mapping and Localization in Urban Environments Using Cameras

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    In this work we present a system to fully automatically create a highly accurate visual feature map from image data aquired from within a moving vehicle. Moreover, a system for high precision self localization is presented. Furthermore, we present a method to automatically learn a visual descriptor. The map relative self localization is centimeter accurate and allows autonomous driving

    Modelling Non-residential Real Estate Prices and Land Use Development in Windsor with Potential Impacts from the Windsor-Essex Parkway

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    A study of non-residential land use in the Windsor, Ontario CMA was undertaken to examine possible local implications from construction of the Windsor-Essex Parkway. Two distinct model types were employed. The first consisted of price regressions for industrial, vacant, commercial, office, retail, restaurant, and plaza properties. The second set studied the discrete choice of land use types within commercial and industrial zoning. The commercial logit model had four alternatives: office, retail, restaurant, and other. The industrial logit model had three alternatives: warehouse, factory, and other. The results obtained from these models provide a useful account of interacting land use processes that can inform future transportation and land use policies. Moreover, the empirical analysis is particularly valuable given the larger amount of research into residential land use compared to non-residential. Finally, the models may be useful in the future as part of a more complex integrated urban model

    A Landsat-based analysis of tropical forest dynamics in the Central Ecuadorian Amazon : Patterns and causes of deforestation and reforestation

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    Tropical deforestation constitutes a major threat to the Amazon rainforest. Monitoring forest dynamics is therefore necessary for sustainable management of forest resources in this region. However, cloudiness results in scarce good quality satellite observations, and is therefore a major challenge for monitoring deforestation and for detecting subtle processes such as reforestation. Furthermore, varying human pressure highlights the importance of understanding the underlying forces behind these processes at multiple scales but also from an interand transdisciplinary perspective. Against this background, this study analyzes and recommends different methodologies for accomplishing these goals, exemplifying their use with Landsat timeseries and socioeconomic data. The study cases were located in the Central Ecuadorian Amazon (CEA), an area characterized by different deforestation and reforestation processes and socioeconomic and landscape settings. Three objectives guided this research. First, processing and timeseries analysis algorithms for forest dynamics monitoring in areas with limited Landsat data were evaluated, using an innovative approach based in genetic algorithms. Second, a methodology based in image compositing, multisensor data fusion and postclassification change detection is proposed to address the limitations observed in forest dynamics monitoring with timeseries analysis algorithms. Third, the evaluation of the underlying driving forces of deforestation and reforestation in the CEA are conducted using a novel modelling technique called geographically weight ridge regression for improving processing and analysis of socioeconomic data. The methodology for forest dynamics monitoring demonstrates that despite abundant data gaps in the Landsat archive for the CEA, historical patterns of deforestation and reforestation can still be reported biennially with overall accuracies above 70%. Furthermore, the improved methodology for analyzing underlying driving forces of forest dynamics identified local drivers and specific socioeconomic settings that improved the explanations for the high deforestation and reforestation rates in the CEA. The results indicate that the proposed methodologies are an alternative for monitoring and analyzing forest dynamics, particularly in areas where data scarcity and landscape complexity require approaches that are more specialized.Landsat-basierte Analyse der Dynamik tropischer WĂ€lder im Zentral-Ecuadorianischen Amazonasgebiet: Muster und Ursachen von Abholzung und Wiederaufforstung Die tropische Entwaldung stellt eine große Bedrohung fĂŒr den AmazonasRegenwald dar. Daher ist die Überwachung von Walddynamiken eine notwendige Maßnahme, um eine nachhaltige Bewirtschaftung der Waldressourcen in dieser Region zu gewĂ€hrleisten. Jedoch verschlechtert Bewölkung die QualitĂ€t der Satellitenaufnahmen und stellt die hauptsĂ€chliche Herausforderung fĂŒr die Überwachung der Entwaldung sowie die Detektierung einhergehender Prozesse, wie der Wiederaufforstung, dar. DarĂŒber hinaus zeigt der unterschiedliche menschliche Nutzungsdruck, wie wichtig es ist, die zugrundeliegenden KrĂ€fte hinter diesen Prozessen auf mehreren Ebenen, aber auch interund transdisziplinĂ€r, zu verstehen. Variierender anthropogener Einfluss unterstreicht die Notwendigkeit, unterschwellige Prozesse (oder "Driver") auf multiplen Skalen aus interund transdisziplinĂ€rer Sicht zu verstehen. Darauf basierend analysiert und empfiehlt die vorliegende Studie unterschiedliche Methoden, welche unter Verwendung von LandsatZeitreihen und sozioökonomischen Daten zur Erreichung dieser Ziele beitragen. Die Untersuchungsgebiete befinden sich im ZentralEcuadorianischen Amazonasgebiet (CEA). Einem Gebiet, das einerseits durch differenzierte Entwaldungsund Aufforstungsprozesse, andererseits durch seine sozioökonomischen und landschaftlichen Gegebenheiten geprĂ€gt ist. Das Forschungsprojekt hat drei Zielvorgaben. Erstens werden auf genetischen Algorithmen basierten Verfahren zur Verarbeitung der Zeitreihenanalyse fĂŒr die Überwachung der Walddynamik in Gebieten, fĂŒr die nur begrenzte LandsatDaten vorhanden waren, bewertet. Zweitens soll eine Methode in Anlehnung an Satellitenbildkompositen, Datenfusion von mehreren Satellitenbildern und VerĂ€nderungsdetektion gefunden werden, die EinschrĂ€nkungen der Walddynamik durch Entwaldung mithilfe von ZeitreihenAlgorithmen thematisiert. Drittens werden die Ursachen der Entwaldung/Abholzung im CEA anhand der geographischen gewichteten RidgeRegression, die zur einen verbesserten Analyse der sozioökonomischen Information beitrĂ€gt, bewertet. Die Methodik fĂŒr das WalddynamikMonitoring zeigt, dass trotz umfangreicher DatenlĂŒcken im LandsatArchiv fĂŒr das CEA alle zwei Jahre die historischen Entwaldungsund Wiederaufforstungsmuster mit einer Genauigkeit von ĂŒber 70% gemeldet werden können. Eine verbesserte Analysemethode trĂ€gt außerdem dazu bei, die fĂŒr die Walddynamik verantwortlichen treibenden KrĂ€fte zu identifizieren, sowie lokale Treiber und spezifische sozioökonomische Rahmenbedingungen auszumachen, die eine bessere ErklĂ€rung fĂŒr die hohen Entwaldungsund Wiederaufforstungsraten im CEA aufzeigen. Die erzielten Ergebnisse machen deutlich, dass die vorgeschlagenen Methoden eine Alternative zum Monitoring und zur Analyse der Walddynamik darstellen; Insbesondere in Gebieten, in denen Datenknappheit und LandschaftskomplexitĂ€t spezialisierte AnsĂ€tze erforderlich machen
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