Ingeniería (Dr.)

Permanent URI for this collectionhttp://54.81.141.168/handle/123456789/72094

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search.filters.applied.f.advisor: search.filters.advisor.Beltrán Castañón, César Armando

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    Distributed Hyperspectral Image Analysis based on Cloud Computing Architectures
    (Pontificia Universidad Católica del Perú, 2022-10-11) Ayma Quirita, Victor Andres; Beltrán Castañón, César Armando
    In this thesis, we introduce a novel distributed version of the N-FINDR endmember extraction algorithm, which is able to exploit computer cluster resources in order to efficiently process large volumes of hyperspectral remote sensing data. The implementation of the distributed algorithm was done by extending the InterCloud Data Mining Package capabilities, originally adopted for land cover classification, through the HyperCloud-RS framework, here adapted for performing endmember extraction processes, which can be likewise executed on cloud computing environments, allowing users to elastically access and exploit processing power and storage space within cloud computing architectures, for adequately processing large volumes of hyperspectral data. The framework supports distributed execution, network communication, and fault tolerance, transparently and efficiently to the user. The experimental analysis addresses the performance issues, assessing both accuracy and execution time, over the processing of different synthetic versions of the AVIRIS Cuprite hyperspectral dataset, with 3.1 Gb, 6.2 Gb, and 15.1Gb respectively, thus addressing the issue of dealing with large-scale hyperspectral data. As a further contribution of this work, we describe in detail how to extend the HyperCloud-RS framework by integrating new endmember extraction algorithms within the proposed architecture, thus enabling researchers to implement their own distributed endmember extraction approaches specifically designed for processing large volumes of hyperspectral data.
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    Classifier based on straight line segments: an overview and theoretical improvements
    (Pontificia Universidad Católica del Perú, 2022-09-09) Medina Rodríguez, Rosario Alejandra; Beltrán Castañón, César Armando
    Literature offers several supervised machine learning algorithms focused on binary classification for solving daily problems. Compared to well-known conventional classifiers, the Straight-line Segment Classifier (SLS Classifier) stands out for its low complexity and competitiveness. It takes advantage of some good characteristics of Learning Vector Quantization and Nearest Feature Line. In addition, it has lower computational complexity than Support Vector Machines. The SLS binary classifier is based on distances between a set of points and two sets of straight line segments. Therefore, it involves finding the optimal placement of straight line segment extremities to achieve the minimum mean square error. In previous works, we explored three different evolutive algorithms as optimization methods to increase the possibilities of finding a global optimum generating different solutions as the initial population. Additionally, we proposed a new way of estimating the number of straight line segments by applying an unsupervised clustering method. However, some interesting questions remained to be further analyzed, such as a detailed analysis of the parameters and base definitions of the optimization algorithm. Furthermore, it was straightforward that the straight-line segment lengths can grow significantly during the training phase, negatively impacting the classification rate. Therefore, the main goal of this thesis is to outline the SLS Classifier baseline and propose some theoretical improvements, such as (i) Formulating an optimization approach to provide optimal final positions for the straight line segments; (ii) Proposing a model selection approach for the SLS Classifier; and, (iii) Determining the SLS Classifier performance when applied on real problems (10 artificial and 8 UCI public datasets). The proposed methodology showed promising results compared to the original SLS Classifier version and other classifiers. Moreover, this classifier can be used in research and industry for decisionmaking problems due to the straightforward interpretation and classification rates.