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Probability of default estimation in credit risk using mixture cure models
Get PDF[Abstract]: An estimator of the probability of default (PD) in credit risk is proposed. It is derived from a nonparametric conditional survival function estimator based on cure models. Asymptotic expressions for the bias and the variance, as well as the asymptotic normality of the proposed estimator are presented. A simulation study shows the performance of the nonparametric estimator compared with Beran's PD estimator and other semiparametric methods. Finally, an empirical study based on modified real data illustrates the practical behaviour.This research has been supported by MICINN Grant PID2020-113578RB-100 , by the Xunta de Galicia (Grupo de Referencia Competitiva ED431C-2020-14 and Centro Singular de Investigación de Galicia ED431G 2019/01), all of them through the ERDF and by the European Research Council (2016-2022, Horizon 2020 / ERC grant agreement No. 694409 ). Peláez, R. was sponsored by inMOTION Programme of grants for pre-doctoral stays Inditex-UDC 2021.Xunta de Galicia; ED431C-2020-14Xunta de Galicia; ED431G 2019/0
Evolution of the Equations of the Shuttle Run Test 20m to Obtain VO2max: Documentary Review
Get PDF[Resumen] Para la evaluación del fitness cardiorrespiratorio existen pruebas directas en laboratorio que proporcionan información objetiva respecto a esta cualidad. No obstante, cuando no se cuenta con los recursos se recurre al uso de pruebas de campo como el Shuttle Run Test 20 metros (SRT-20m), el cual busca establecer el VO2max para cada sujeto, relacionando los valores obtenidos con aspectos como la composición corporal, edad y contexto poblacional, siendo una de las pruebas más confiables y con concordancia clínica existente. El propósito fue reconocer los cambios o variaciones presentes en los modelos matemáticos o lineales empleados en esta prueba con diferentes grupos poblacionales. Se realizó una revisión de la literatura bajo el marco básico para revisiones integradoras con algunas precisiones dadas por la guía PRISMA, identificando en su mayoría estudios de corte transversal los cuales evidencian los cambios realizados al planteamiento de la fórmula matemática donde las variables que inciden en el valor resultante para la resistencia aeróbica son: velocidad final, etapa de la prueba, edad y aspectos antropométricos del sujeto. Por lo anterior, se concluye que, para efectos prácticos, la estimación del VO2máx debe considerar factores intrínsecos del sujeto y aquellos relacionados con la ejecución de la prueba.[Abstract] For the evaluation of cardiorespiratory fitness, there are direct laboratory tests that provide objective information regarding this quality. However, when the resources are not available, the use of field tests such as the Shuttle Run Test 20 meters (SRT-20m) is used, which seeks to establish the VO2max for each subject, relating the values obtained with aspects such as body composition, age, and population context, being one of the most reliable tests with existing clinical agreement. The purpose was to recognize the changes or variations present in the mathematical or linear models used in this test with different population groups. A review of the literature was carried out under the basic framework for integrative reviews with some clarifications given by the PRISMA guide, identifying mostly cross-sectional studies which show the changes made to the approach of the mathematical formula where the variables that affect the resulting value for aerobic endurance are final speed, stage of the test, age, and anthropometric aspects of the subject. Therefore, it is concluded that, for practical purposes, the estimation of VO2max should consider intrinsic factors of the subject and those related to the execution of the test
Rigidity of weighted Einstein smooth metric measure spaces
Get PDFFunding for open access: Universidade da Coruña/CISUG.[Abstract] We study the geometric structure of weighted Einstein smooth metric measure spaces with weighted harmonic Weyl tensor. A complete local classification is provided, showing that either the underlying manifold is Einstein, or decomposes as a warped product in a specific way. Moreover, if the manifold is complete, then it either is a weighted analogue of a space form, or it belongs to a particular family of Einstein warped products.[Résumé] Nous étudions la structure géométrique des smooth metric measure spaces (variétés différentielles avec densité) pondérés d'Einstein avec un tenseur de Weyl harmonique pondérée. Nous allons fournir une classification locale complète, montrant que soit la variété sous-jacente est d'Einstein, soit elle se décompose en un produit déformé, d'une manière spécifique. De plus, si la variété est complète, alors elle est soit une version pondérée d'une forme d'espace, soit elle appartient à une famille particulière de produits déformés d'Einstein.Xunta de Galicia; ED431F 2020/0
A Novel Protocol Using Captive Portals for FIDO2 Network Authentication
Get PDFThis paper is an extended version of the paper published in the international conference: 2023 JNIC Cybersecurity Conference (JNIC), Vigo, Spain, 21–23 June 2023.The developed prototype can be found in Github, published as Open Source: https://github.com/martinord/fido2cap-server (accessed on 23 April 2024).[Abstract]: FIDO2 authentication is starting to be applied in numerous web authentication services, aiming to replace passwords and their known vulnerabilities. However, this new authentication method has not been integrated yet with network authentication systems. In this paper, we introduce FIDO2CAP: FIDO2 Captive-portal Authentication Protocol. Our proposal describes a novel protocol for captive-portal network authentication using FIDO2 Authenticators as security keys and passkeys. For validating our proposal, we have developed a prototype of FIDO2CAP authentication in a mock scenario. Using this prototype, we performed a usability experiment with 15 real users. This work makes the first systematic approach for adapting network authentication to the new authentication paradigm relying on FIDO2 authentication.This work was founded by EU and “Xunta de Galicia” (Spain), grant ED431C 2022/46-Competitive Reference Groups GRC. This work was also supported by CITIC, funded by “Xunta de Galicia” through the collaboration agreement between the “Consellería de Cultura, Educación, Formación Profesional e Universidades” and the Galician universities to strengthen the research centres of the “Sistema Universitario de Galicia” (CIGUS). Also, the work is founded by the “Formación de Profesorado Universitario” (FPU) grant from the Spanish Ministry of Universities to Martiño Rivera Dourado (Grant FPU21/04519).Xunta de Galicia; ED431C 2022/4
Portrait of prostitution: the look of Spanish audiovisual cinematographic production
Get PDF[Resumo] O cine, como espazo multidimensional onde o simbólico ten unha importante función produtora e reprodutora, é capaz de construír, por medio da ficción, realidades e imaxinarios asumidos colectivamente sen simular, sequera, que o está a facer. Cando o seu poder se une a outro maior, o do patriarcado, nunha retroalimentación que pasa inadvertida, é preciso abrir os ollos. Da necesidade dunha apertura de miras, xorde o presente traballo coa seguinte premisa de partida: se o cine español está a retratar adecuadamente una problemática social tan complexa como a prostitución ou se, pola contra, co discurso fílmico que ofrece está a ser cómplice, aínda na actualidade, dun sistema prostitucional ao servizo dos intereses patriarcais.
Ao longo das seguintes páxinas tentarase describir dun modo exhaustivo o retrato da prostitución debuxado pola produción audiovisual cinematográfica española do último século, con inferencia tanto na veracidade á hora de abordar esta problemática como na influencia social que exerce. Para elo, profundarase dende o método mixto nunha mostra de cen filmes españois que, de forma central ou tanxencial, referencian a prostitución. Será a inclusión da análise crítica do discurso a que permita poñer en relación o relato prostitucional cinematográfico coa problemática da prostitución e a trata de persoas con fins de explotación sexual, a fin de verificar a realidade do exposto e afondar no impacto social derivado.[Resumen] El cine, como espacio multidimensional donde lo simbólico tiene una importante función productora y reproductora, es capaz de construir, por medio de la ficción, realidades e imaginarios asumidos colectivamente sin simular, siquiera, que lo está haciendo. Cuando su poder se une a otro mayor, el del patriarcado, en una retroalimentación que pasa inadvertida, es necesario abrir los ojos. De la necesidad de una apertura de miras, surge el presente trabajo con la siguiente premisa de partida: si el cine español está retratando adecuadamente una problemática social tan compleja como la prostitución o si, por el contrario, con el discurso fílmico que ofrece está siendo cómplice, aún en la actualidad, de un sistema prostitucional al servicio de los intereses patriarcales.
A lo largo de las siguientes páginas se intentará describir de un modo exhaustivo el retrato de la prostitución dibujado por la producción audiovisual cinematográfica española del último siglo, con inferencia tanto en la veracidad a la hora de abordar esta problemática como en la influencia social que ejerce. Para ello, se profundizará desde el método mixto en una muestra de cien filmes españoles que, de forma central o tangencial, referencian la prostitución. Será la inclusión del análisis crítico del discurso la que permita poner en relación el relato prostitucional cinematográfico con la problemática de la prostitución y la trata de personas con fines de explotación sexual, a fin de verificar la realidad de lo expuesto y ahondar en el impacto social derivado.[Abstract] The cinema, like multidimensional space where the symbolic has an important producing and reproducing function, is able to build, by means of the fiction, realities and imaginary assumed collectively without simulating, at least, that is doing it. When his can joins to another elder, the one of the patriarchy, in a feedback that happens careless, is necessary to open the eyes. Of the need of an opening of look, arises the present work with the following premise of game: if the Spanish cinema is portraying properly a problematic social so complex like the prostitution or if, by the contrary, with the film speech that offers is being accomplice, still in the actuality, of a prostitutional system to the service of the patriarchal interests. Along the following pages will try to describe of an exhaustive way the portrait of the prostitution drawn by the cinematographic audiovisual production Spaniard of the last century, with inference so much in the veracity to the hour to tackle this problematic as in the social influence that exerts. For this, will deepen from the mixed method in a sample of one hundred spanish films that, of central or tangential form, reference the prostitution. It will be the inclusion of the critical analysis of the speech the one who allow to put in relation the cinematographic prostitutional relate with the problematic of the prostitution and treats it of people with ends of sexual exploitation, to end to verify the reality of the exposed and deepen in the social impact derived.Traballo fin de grao (UDC.SOC). Socioloxía. Curso 2023/202
Effect of Resistance Training Programs With Equated Power on Older Adults' Functionality and Strength: A Randomized Controlled Trial
Get PDF© 2023 National Strength and Conditioning Association. Versión aceptada de: Fraga-Germade, Enrique1; Carballeira, Eduardo1,2; Iglesias-Soler, Eliseo1. Effect of Resistance Training Programs With Equated Power on Older Adults' Functionality and Strength: A Randomized Controlled Trial. Journal of Strength and Conditioning Research 38(1):p 153-163, January 2024. | DOI: 10.1519/JSC.0000000000004588This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/bync-nd/4.0/. This version of the article has been accepted for publication in Journal of Strength and Conditioning Research. The Version of Record is available online at DOI: 10.1519/JSC.0000000000004588[Abstract]: This study aimed to compare the effect of 2 training programs of equated power but differing in load intensity on older adults' functionality, strength, performance, and body composition. Forty-four active (23 female) older adults (66.3 ± 4.5 years) were randomly assigned to low-load high-velocity (LL-HV), high-load low-velocity (HL-LV), and control (CON) groups. Low-load high-velocity and HL-LV performed, twice weekly for 5 weeks, a resistance training program at 95% of their individual peak power (PP) but with different load intensities for 3 exercises: chest press (CHP), leg press (LP), and seated row (SR). Before and after the intervention, body composition, functional performance, maximal voluntary isokinetic force (MVF), PP, and a relative load-power profile (L-PP) were evaluated for every exercise. PP similarly improved in the experimental groups for SR and LP (p < 0.05). Both groups increased their MVF for the 3 exercises (p < 0.05). Positive effects on L-PP were observed in LL-HV for SR (p = 0.009) and HL-LV for LP (p < 0.001). CON decreased its global power performance in SR (p = 0.009) and CHP (p = 0.031) compared with the baseline. Both experimental groups improved Timed Up and Go performance (p < 0.05), but only HL-LV increased 6-minute walking performance (pre: 514.3 ± 89.0 m, post: 552.6 ± 65.4 m; p < 0.05). In conclusion, adding short-term power training (i.e., 10 sessions throughout 5 weeks) with loads slightly above the optimal load to nonsupervised multicomponent training might improve active older adults' functional performance and cardiovascular endurance
Stronger compact representations of object trajectories
Get PDF[Absctract]: GraCT and ContaCT were the first compressed data structures to represent object trajectories, demonstrating that it was possible to use orders of magnitude less space than classical indexes while staying competitive in query times. In this paper we considerably enhance their space, query capabilities, and time performance with three contributions. (1) We design and evaluate algorithms for more sophisticated nearest neighbor queries, finding the trajectories closest to a given trajectory or to a given point during a time interval. (2) We modify the data structure used to sample the spatial positions of the objects along time. This improves the performance on the classic spatio-temporal and the nearest neighbor queries, by orders of magnitude in some cases. (3) We introduce RelaCT, a tradeoff between the faster and larger ContaCT and the smaller and slower GraCT, offering a new relevant space-time tradeoff for large repetitive datasets of trajectories.For the A Coruña team: This work was supported by GAIN/Xunta de Galicia: GRC: grants ED431C 2021/53, and CIGUS 2023-2026; Ministerio de Ciencia e Innovación and EU/ERDF A way of making Europe under grant [PID2022-141027NB-C21];Ministerio de Ciencia e Innovación under grant [PID2020-114635RB-I00]; Ministerio de Ciencia e Innovación and Next-GenerationEU/PRTR under grants [TED2021-129245B-C21; PDC2021-120917-C21]; Gonzalo Navarro was funded by ANID – Millennium Science Initiative Program – Code ICN17_002 and by Fondecyt under grants [1-200038; 1-230755]. Travis Gagie was funded by Fondecyt under grant [1171058] and by NSERC Discovery under grant [RGPIN-07185-2020].Xunta de Galicia; ED431C 2021/53Xunta de Galicia; CIGUS 2023-2026Chile. National Agency of Research and Development (ANID); ICN17_002Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 1-200038Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 1-230755Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 1171058Canada. Natural Science and Engineering Research Council (NSERC); RGPIN-07185-202
The Ring: Worst-case Optimal Joins in Graph Databases using (Almost) No Extra Space
Get PDF© ACM 2024. This is the author's version of the work (accepted manuscript
or postprint). It is posted here for your personal use. Not for redistribution.
The definitive Version of Record was published in ACM Transactions on
Database Systems, https://doi.org/10.1145/3644824[Absctract]: We present an indexing scheme for triple-based graphs that supports join queries in worst-case optimal (wco) time within compact space. This scheme, called a ring, regards each triple as a cyclic string of length 3. Each rotation of the triples is lexicographically sorted and the values of the last attribute are stored as a column, so we obtain the order of the next column by stably re-sorting the triples by its attribute. We show that, by representing the columns with a compact data structure called a wavelet tree, this ordering enables forward and backward navigation between columns without needing pointers. These wavelet trees further support wco join algorithms and cardinality estimations for query planning. While traditional data structures such as B-Trees, tries, and so on, require 6 index orders to support all possible wco joins over triples, we can use one ring to index them all. This ring replaces the graph and uses only sublinear extra space, thus supporting wco joins in almost no space beyond storing the graph itself. Experiments querying a large graph (Wikidata) in memory show that the ring offers nearly the best overall query times while using only a small fraction of the space required by several state-of-the-art approaches.
We then turn our attention to some theoretical results for indexing tables of arity d higher than 3 in such a way that supports wco joins. While a single ring of length d no longer suffices to cover all d! orders, we need much fewer rings to index them all: O(2d) rings with a small constant. For example, we need 5 rings instead of 120 orders for d=5. We show that our rings become a particular case of what we dub order graphs, whose nodes are attribute orders and where stably sorting by some attribute leads us from an order to another, thereby inducing an edge labeled by the attribute. The index is then the set of columns associated with the edges, and a set of rings is just one possible graph shape. We show that other shapes, like for example a single ring instead of several ones of length d, can lead us to even smaller indexes, and that other more general shapes are also possible. For example, we handle d=5 attributes within space equivalent to 4 rings.We thank Amine Mhedhbi for help with Graphflow and Daniela Campos for help with CompactLTJ.
This work was supported by ANID – Millennium Science Initiative Program – Code ICN17_002.
Gómez-Brandón was supported in part by MCIN/AEI/10.13039/5011000-11033: grants PID2020-
114635RB-I00; by MCIN/AEI/10.13039/501100011033 and EU/ERDF "A way of making Europe":
PID2022-141027NB-C21; by MCIN/AEI/10.13039/501100011033 and “Next-GenerationEU”/ PRTR:
grants TED2021-129245B-C21, PDC2021-120917-C21 and by GAIN/ Xunta de Galicia: GRC: grants
ED431C 2021/53, and CIGUS 2023-2026. Hogan was supported by FONDECYT Grant No. 1221926.
Navarro was supported by FONDECYT Grant No. 1230755. Reutter was supported by FONDECYT
Grant No. 1221799.Xunta de Galicia; ED431C 2021/53Xunta de Galicia; CIGUS 2023-2026Chile. Agencia Nacional de Investigación y Desarrollo; ICN17_002Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 1221926Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 1230755Chile. Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt); 122179
Spanish Resource Grammar Version 2023
Get PDFProceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024), held in Torino (Italia)
20-25 May, 2024.[Abstract]: We present the latest version of the Spanish Resource Grammar (SRG), a grammar of Spanish implemented in the HPSG formalism. Such grammars encode a complex set of hypotheses about syntax making them a resource for empirical testing of linguistic theory. They also encode a strict notion of grammaticality which makes them a resource for natural language processing applications in computer-assisted language learning. This version of the SRG uses the recent version of the Freeling morphological analyzer and is released along with an automatically created, manually verified treebank of 2,291 sentences. We explain the treebanking process, emphasizing how it is different from treebanking with manual annotation and how it contributes to empirically-driven development of syntactic theory. The treebanks’ high level of consistency and detail makes them a resource for training high-quality semantic parsers and generally systems that benefit from precise and detailed semantics. Finally, we present the grammar’s coverage and overgeneration on 100 sentences from a learner corpus, a new research line related to developing methodologies for robust empirical evaluation of hypotheses in second language acquisition.We acknowledge the European Union’s Horizon Europe Framework Programme which funded this
research under the Marie Skłodowska-Curie post-doctoral fellowship grant HORIZON-MSCA-2021-PF-01 (GAUSS, grant agreement No 101063104); the European Research Council (ERC), which has
funded this research under the Horizon Europe research and innovation programme (SALSA, grant
agreement No 101100615); Grant SCANNER-UDC (PID2020-113230RB-C21) funded by MICIU/AEI/10.13039/501100011033; Xunta de Galicia (ED431C 2020/11); and Centro de Investigación
de Galicia “CITIC”, funded by the Xunta de Galicia through the collaboration agreement between the
Consellería de Cultura, Educación, Formación Profesional e Universidades and the Galician universities for the reinforcement of the research centres of the Galician University System (CIGUS). We also
acknowledge grant GAP (PID2022-139308OA-I00) funded by MCIN/AEI/10.13039/501100011033/
and by ERDF “A way of making Europe”.Xunta de Galicia; ED431C 2020/1
