622,488 research outputs found

    Transmuted Lindley-Geometric Distribution and its applications

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    A functional composition of the cumulative distribution function of one probability distribution with the inverse cumulative distribution function of another is called the transmutation map. In this article, we will use the quadratic rank transmutation map (QRTM) in order to generate a flexible family of probability distributions taking Lindley geometric distribution as the base value distribution by introducing a new parameter that would offer more distributional flexibility. It will be shown that the analytical results are applicable to model real world data.Comment: 20 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1309.326

    Dimensionality Reduction Methods for the Functional Map of the World Dataset

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    Algoritmy redukce dimenze jsou skvělé pro hlubší pochopení datového souboru. V posledních letech jsme viděli růst algoritmů pro výběr prvků, konkrétně podtřídy sousedních grafů. V této práci jsme se zaměřili na nejmodernější algoritmus UMAP a aplikovali jsme na nejmodernější datový soubor fMoW. Poté porovnáme výsledky UMAP se starší konkurenční metodou t-SNE. Podíváme se na silné a slabé stránky obou metod a možné obtíže při aplikaci na komplexní datový soubor fMoW. Na základě těchto výsledků implementujeme a školíme neuronovou síť EfficientNet na datovém souboru fMoW.Dimensionality reduction algorithms are great for a deeper understanding of the dataset. In recent years we saw grow of feature selection algorithms more specifically subclass of neighbor graphs. In this work, we focused on the state of the art algorithm UMAP and applicated for the state of the art fMoW dataset. We then compare UMAP results, with older competing method t-SNE. We look at there strengths and weaknesses of both methods and possible difficulties in the application on the complex fMoW dataset. Based on these results, we implement and trained EfficientNet neural network on the fMoW dataset

    Robust spatial memory maps encoded in networks with transient connections

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    The spiking activity of principal cells in mammalian hippocampus encodes an internalized neuronal representation of the ambient space---a cognitive map. Once learned, such a map enables the animal to navigate a given environment for a long period. However, the neuronal substrate that produces this map remains transient: the synaptic connections in the hippocampus and in the downstream neuronal networks never cease to form and to deteriorate at a rapid rate. How can the brain maintain a robust, reliable representation of space using a network that constantly changes its architecture? Here, we demonstrate, using novel Algebraic Topology techniques, that cognitive map's stability is a generic, emergent phenomenon. The model allows evaluating the effect produced by specific physiological parameters, e.g., the distribution of connections' decay times, on the properties of the cognitive map as a whole. It also points out that spatial memory deterioration caused by weakening or excessive loss of the synaptic connections may be compensated by simulating the neuronal activity. Lastly, the model explicates functional importance of the complementary learning systems for processing spatial information at different levels of spatiotemporal granularity, by establishing three complementary timescales at which spatial information unfolds. Thus, the model provides a principal insight into how can the brain develop a reliable representation of the world, learn and retain memories despite complex plasticity of the underlying networks and allows studying how instabilities and memory deterioration mechanisms may affect learning process.Comment: 24 pages, 10 figures, 4 supplementary figure

    Focusing on the Big Picture: Insights into a Systems Approach to Deep Learning for Satellite Imagery

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    Deep learning tasks are often complicated and require a variety of components working together efficiently to perform well. Due to the often large scale of these tasks, there is a necessity to iterate quickly in order to attempt a variety of methods and to find and fix bugs. While participating in IARPA's Functional Map of the World challenge, we identified challenges along the entire deep learning pipeline and found various solutions to these challenges. In this paper, we present the performance, engineering, and deep learning considerations with processing and modeling data, as well as underlying infrastructure considerations that support large-scale deep learning tasks. We also discuss insights and observations with regard to satellite imagery and deep learning for image classification.Comment: Accepted to IEEE Big Data 201

    Functional Capacity Assessed by the Map Task in Individuals at Clinical High-Risk for Psychosis

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    Recent studies have recognized that signs of functional disability in schizophrenia are evident in early phases of the disorder, and, as a result, can potentially serve as vulnerability markers of future illness. However, functional measures in the psychosis prodrome have focused exclusively on real-world achievements, rather than on the skills required to carry-out a particular real-world function (ie, capacity). Despite growing evidence that diminished capacity is critical to the etiology of the established disorder, virtually no attention has been directed towards assessing functional capacity in the pre-illness stages. In the present study, we introduce the Map task, a measure to assess functional capacity in adolescent and young-adult high-risk populations
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