1,720,955 research outputs found
Corporate risk stratification through an interpretable autoencoder-based model
Full text linkIn this manuscript, we propose an innovative early warning Machine Learning-based model to identify potential threats to financial sustainability for non-financial companies. Unlike most state-of-the-art tools, whose outcomes are often difficult to understand even for experts, our model provides an easily interpretable visualization of balance sheets, projecting each company in a bi-dimensional space according to an autoencoder-based dimensionality reduction matched with a Nearest-Neighbor-based default density estimation. In the resulting space, the distress zones, where the default intensity is high, appear as homogeneous clusters directly identified. Our empirical experiments provide evidence of the interpretability, forecasting ability, and robustness of the bi-dimensional space
Full 3D Modelling of Scenes with Complex Surface Reflectance
Full text linkMany industrial fields such as digital entertainment and heritage preservation make use of 3D reconstruction techniques to produce digital copies of objects from the real world. From the advent of 3D computer vision, researchers have been exploring a broad variety of approaches to infer scene geometry from visual input, tackling increasingly more complex classes of objects while improving the modelling accuracy. To date, however, many of these techniques still operate under simplifying assumptions on the reconstructed scene surface reflectance, effectively restricting the range of objects that can be correctly reconstructed. Helmholtz Stereopsis is a technique that allows to perform 3D reconstruction regardless of the surface reflectance of the target object. The technique exploits a principle from Physics called Helmholtz reciprocity, which describes the reversibility of light transport paths. Despite the advantages this brings, most Helmholtz Stereopsis formulations to date have been limited to 2.5D reconstruction, and the few exceptions do not achieve global optimality guarantees in the full 3D domain. To address this gap, there is a need for better scene modelling techniques that are not only agnostic to surface reflectance but capable of achieving a full 3D reconstruction.The main contribution of this work is the introduction of a family of full 3D Helmholtz Stereopsis approaches. The contributed methods are divided in view-dependent and full 3D approaches. The view-dependent formulations consist in producing multiple 2.5D surfaces obtained from different view-points around the object. The full 3D techniques are instead divided in a volumetric formulation, which estimates the target surface occupancy in a voxel grid, and a mesh-based formulation, which optimises the vertices position of an initialisation topology. Additional methods are presented to perform segmentation in Helmholtz datasets and to handle visibility where incomplete geometric data is available. All presented approaches are evaluated on both synthetic and real datasets, including novel datasets contributed as part of this research.The first mobile Helmholtz Stereopsis capture setup is also introduced in this work, consisting of two cameras equipped with external flashes. The setup is used to produce the aforementioned datasets, which are utilised in the evaluation section of each methodology presented and could be adopted in the future to benchmark new Helmholtz Stereopsis formulations. An extensive analysis is also carried out to understand how the cameras position in a Helmholtz setup influences the reconstruction outcome and modelling accuracy. In particular, so called degenerate configurations are studied and the results obtained are leveraged to maximise the reconstruction outcome of Helmholtz Stereopsis setups and to improve the fusion process in the view-dependent approaches
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
An MRF Optimisation Framework for Full 3D Helmholtz Steropsis
Full text linkAccurate 3D modelling of real world objects is essential in many applications such as digital film production and cultural heritage preservation. However, current modelling techniques rely on assumptions to constrain the problem, effectively limiting the categories of scenes that can be reconstructed. A common assumption is that the scene’s surface reflectance is Lambertian or known a priori. These constraints rarely hold true in practice and result in inaccurate reconstructions. Helmholtz Stereopsis (HS) addresses this limitation by introducing a reflectance agnostic modelling constraint, but prior work in this area has been predominantly limited to 2.5D reconstruction, providing only a partial model of the scene. In contrast, this paper introduces the first Markov Random Field (MRF) optimisation framework for full 3D HS. First, an initial reconstruction is obtained by performing 2.5D MRF optimisation with visibility constraints from multiple viewpoints and fusing the different outputs. Then, a refined 3D model is obtained through volumetric MRF optimisation using a tailored Iterative Conditional Modes (ICM) algorithm. The proposed approach is evaluated with both synthetic and real data. Results show that the proposed full 3D optimisation significantly increases both geometric and normal accuracy, being able to achieve sub-millimetre precision. Furthermore, the approach is shown to be robust to occlusions and noise
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