13 results
Search Results
2. The Challenges of Algorithm Management: The Spanish Perspective.
- Author
-
Prado, Daniel Perez del
- Subjects
ALGORITHMS ,LABOR laws ,DISRUPTIVE innovations ,ARTIFICIAL intelligence ,DIGITAL technology - Abstract
This paper focuses on how Spain's labour and employment law is dealing with technological disruption and, particularly, with algorithm management, looking for a harmonious equilibrium between traditional structures and profound changes. It pays special attention to the different actors affected and the most recent normative changes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Confidence of a k-Nearest Neighbors Python Algorithm for the 3D Visualization of Sedimentary Porous Media.
- Author
-
Bullejos, Manuel, Cabezas, David, Martín-Martín, Manuel, and Alcalá, Francisco Javier
- Subjects
PYTHON programming language ,K-nearest neighbor classification ,POROUS materials ,CONFIDENCE ,ECONOMIC decision making ,ALGORITHMS - Abstract
In a previous paper, the authors implemented a machine learning k-nearest neighbors (KNN) algorithm and Python libraries to create two 3D interactive models of the stratigraphic architecture of the Quaternary onshore Llobregat River Delta (NE Spain) for groundwater exploration purposes. The main limitation of this previous paper was its lack of routines for evaluating the confidence of the 3D models. Building from the previous paper, this paper refines the programming code and introduces an additional algorithm to evaluate the confidence of the KNN predictions. A variant of the Similarity Ratio method was used to quantify the KNN prediction confidence. This variant used weights that were inversely proportional to the distance between each grain-size class and the inferred point to work out a value that played the role of similarity. While the KNN algorithm and Python libraries demonstrated their efficacy for obtaining 3D models of the stratigraphic arrangement of sedimentary porous media, the KNN prediction confidence verified the certainty of the 3D models. In the Llobregat River Delta, the KNN prediction confidence at each prospecting depth was a function of the available data density at that depth. As expected, the KNN prediction confidence decreased according to the decreasing data density at lower depths. The obtained average-weighted confidence was in the 0.44−0.53 range for gravel bodies at prospecting depths in the 12.7−72.4 m b.s.l. range and was in the 0.42−0.55 range for coarse sand bodies at prospecting depths in the 4.6−83.9 m b.s.l. range. In a couple of cases, spurious average-weighted confidences of 0.29 in one gravel body and 0.30 in one coarse sand body were obtained. These figures were interpreted as the result of the quite different weights of neighbors from different grain-size classes at short distances. The KNN algorithm confidence has proven its suitability for identifying these anomalous results in the supposedly well-depurated grain-size database used in this study. The introduced KNN algorithm confidence quantifies the reliability of the 3D interactive models, which is a necessary stage to make decisions in economic and environmental geology. In the Llobregat River Delta, this quantification clearly improves groundwater exploration predictability. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. A K-Nearest Neighbors Algorithm in Python for Visualizing the 3D Stratigraphic Architecture of the Llobregat River Delta in NE Spain.
- Author
-
Bullejos, Manuel, Cabezas, David, Martín-Martín, Manuel, and Alcalá, Francisco Javier
- Subjects
K-nearest neighbor classification ,SUPERVISED learning ,PYTHON programming language ,ALGORITHMS ,MACHINE learning ,SEDIMENTARY structures ,PLIOCENE Epoch - Abstract
The k-nearest neighbors (KNN) algorithm is a non-parametric supervised machine learning classifier; which uses proximity and similarity to make classifications or predictions about the grouping of an individual data point. This ability makes the KNN algorithm ideal for classifying datasets of geological variables and parameters prior to 3D visualization. This paper introduces a machine learning KNN algorithm and Python libraries for visualizing the 3D stratigraphic architecture of sedimentary porous media in the Quaternary onshore Llobregat River Delta (LRD) in northeastern Spain. A first HTML model showed a consecutive 5 m-equispaced set of horizontal sections of the granulometry classes created with the KNN algorithm from 0 to 120 m below sea level in the onshore LRD. A second HTML model showed the 3D mapping of the main Quaternary gravel and coarse sand sedimentary bodies (lithosomes) and the basement (Pliocene and older rocks) top surface created with Python libraries. These results reproduce well the complex sedimentary structure of the LRD reported in recent scientific publications and proves the suitability of the KNN algorithm and Python libraries for visualizing the 3D stratigraphic structure of sedimentary porous media, which is a crucial stage in making decisions in different environmental and economic geology disciplines. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. KNN and adaptive comfort applied in decision making for HVAC systems.
- Author
-
Aparicio-Ruiz, Pablo, Barbadilla-Martín, Elena, Guadix, José, and Cortés, Pablo
- Subjects
THERMAL comfort ,DECISION making ,SUPPORT vector machines ,ALGORITHMS ,AIR conditioning ,HEATING & ventilation industry - Abstract
The decision making of a suitable heating, ventilating and air conditioning system's set-point temperature is an energy and environmental challenge in our society. In the present paper, a general framework to define such temperature based on a dynamic adaptive comfort algorithm is proposed. Due to the fact that the thermal comfort of the occupants of a building has different ranges of acceptability, this method is applied to learn such comfort temperature with respect to the running mean temperature and therefore to decide the suitable range of indoor temperature. It is demonstrated that this solution allows to dynamically build an adaptive comfort algorithm, an algorithm based on the human being's thermal adaptability, without applying the traditional theory. The proposed methodology based on the K-Nearest-Neighbour algorithm was tested and compared with data from an experimental thermal comfort field study carried out in a mixed mode building in the south-western area of Spain and with the Support Vector Machine method. The results show that K-Nearest-Neighbour algorithm represents the pattern of thermal comfort data better than the traditional solution and that it is a suitable method to learn the thermal comfort area of a building and to define the set-point temperature for a heating, ventilating and air-conditioning system. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. Comparison of Optimisation Algorithms for Centralised Anaerobic Co-Digestion in a Real River Basin Case Study in Catalonia.
- Author
-
Palma-Heredia D, Verdaguer M, Puig V, Poch M, and Cugueró-Escofet MÀ
- Subjects
- Anaerobiosis, Digestion, Spain, Algorithms, Rivers
- Abstract
Anaerobic digestion (AnD) is a process that allows the conversion of organic waste into a source of energy such as biogas, introducing sustainability and circular economy in waste treatment. AnD is an intricate process because of multiple parameters involved, and its complexity increases when the wastes are from different types of generators. In this case, a key point to achieve good performance is optimisation methods. Currently, many tools have been developed to optimise a single AnD plant. However, the study of a network of AnD plants and multiple waste generators, all in different locations, remains unexplored. This novel approach requires the use of optimisation methodologies with the capacity to deal with a highly complex combinatorial problem. This paper proposes and compares the use of three evolutionary algorithms: ant colony optimisation (ACO), genetic algorithm (GA) and particle swarm optimisation (PSO), which are especially suited for this type of application. The algorithms successfully solve the problem, using an objective function that includes terms related to quality and logistics. Their application to a real case study in Catalonia (Spain) shows their usefulness (ACO and GA to achieve maximum biogas production and PSO for safer operation conditions) for AnD facilities.
- Published
- 2022
- Full Text
- View/download PDF
7. ALGORITHMIC (IN)VISIBILITY TACTICS AMONG IMMIGRANT TIKTOKERS.
- Author
-
JARAMILLO-DENT, DANIELA
- Subjects
SCIENTIFIC literature ,IMMIGRANTS ,SOCIAL media ,DIGITAL video - Abstract
It is well established in scientific literature that immigrants are excluded from their own stories, which are often instrumentalized to fulfill specific communicative, othering intentions. In this sense, migrant agency and voice are, in many cases, absent from narratives related to their life experiences and subject to various symbolic, digital, and material borders. Moreover, although social media has been recognized as a prime space for self-representation across different segments of society, immigrants are often excluded from these spaces due to the risks that sharing certain information publicly represent to them. In this article I draw from a 16-month digital ethnography and inductive, multimodal content analysis of videos created by 53 Latin American immigrant tiktokers in the United States and Spain. This enables the conceptualization of their algorithmic (in)visibility practices which refer to the set of strategies deployed by immigrant content creators on social media --and possibly other marginalized and vulnerable populations-- to negotiate the conspicuousness of their controversial content with the aim of avoiding its deletion from the platform. The findings unveil three exemplary algorithmic (in)visibility practices that include content reuse and re-upload, vernacular visibility, and partial deplatforming. I find that these strategies shift between collective and individual approaches to achieve selective visibility and concealed conspicuousness within algorithmic moderation systems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
8. La sección "Tendencias" en YouTube en España durante las primeras semanas de la pandemia de Covid-19: visibilidad de las industrias culturales frente a los youtubers.
- Author
-
Patricio Pérez-Rufi, José and Castro-Higueras, Antonio
- Subjects
CULTURAL industries ,SOCIAL responsibility ,COVID-19 ,ACCESS to information ,PRODUCE trade ,USER-generated content - Abstract
Copyright of Estudios sobre el Mensaje Periodistico is the property of Universidad Complutense de Madrid and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
9. An Automatic Algorithm to Date the Reference Cycle of the Spanish Economy.
- Author
-
Camacho, Maximo, Gadea, María Dolores, and Gómez-Loscos, Ana
- Subjects
GAUSSIAN distribution ,BUSINESS cycles ,ECONOMIC indicators ,MARKOV processes ,ALGORITHMS ,RECESSIONS - Abstract
This paper provides an accurate chronology of the Spanish reference business cycle adapting a multiple change-point model. In that approach, each combination of peaks and troughs dated in a set of economic indicators is assumed to be a realization of a mixture of bivariate Gaussian distributions, whose number of components is estimated from the data. The means of each of these components refer to the dates of the reference turning points. The transitions across the components of the mixture are governed by Markov chain that is restricted to force left-to-right transition dynamic. In the empirical application, seven recessions in the period from February 1970 to February 2020 are identified, which are in high concordance with the timing of the turning point dates established by the Spanish Business Cycle Dating Committee (SBCDC). [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. A Method of Estimating Time-to-Recovery for a Disease Caused by a Contagious Pathogen Such as SARS-CoV-2 Using a Time Series of Aggregated Case Reports.
- Author
-
Koutsouris, Dimitrios-Dionysios, Pitoglou, Stavros, Anastasiou, Athanasios, and Koumpouros, Yiannis
- Subjects
DISEASE progression ,COMPUTER software ,COVID-19 ,CONFIDENCE intervals ,TIME ,CONVALESCENCE ,WORLD health ,EPIDEMICS ,TIME series analysis ,DESCRIPTIVE statistics ,SENSITIVITY & specificity (Statistics) ,PREDICTION models ,COVID-19 pandemic ,ALGORITHMS - Abstract
During the outbreak of a disease caused by a pathogen with unknown characteristics, the uncertainty of its progression parameters can be reduced by devising methods that, based on rational assumptions, exploit available information to provide actionable insights. In this study, performed a few (~6) weeks into the outbreak of COVID-19 (caused by SARS-CoV-2), one of the most important disease parameters, the average time-to-recovery, was calculated using data publicly available on the internet (daily reported cases of confirmed infections, deaths, and recoveries), and fed into an algorithm that matches confirmed cases with deaths and recoveries. Unmatched cases were adjusted based on the matched cases calculation. The mean time-to-recovery, calculated from all globally reported cases, was found to be 18.01 days (SD 3.31 days) for the matched cases and 18.29 days (SD 2.73 days) taking into consideration the adjusted unmatched cases as well. The proposed method used limited data and provided experimental results in the same region as clinical studies published several months later. This indicates that the proposed method, combined with expert knowledge and informed calculated assumptions, could provide a meaningful calculated average time-to-recovery figure, which can be used as an evidence-based estimation to support containment and mitigation policy decisions, even at the very early stages of an outbreak. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
11. A study of differential microRNA expression profile in migraine: the microMIG exploratory study.
- Author
-
Gallardo, V. J., Gómez-Galván, J. B., Asskour, L., Torres-Ferrús, M., Alpuente, A., Caronna, E., and Pozo-Rosich, P.
- Subjects
RESEARCH ,MONONUCLEAR leukocytes ,MIGRAINE ,RESEARCH methodology ,MICRORNA ,INTERVIEWING ,CASE-control method ,RANDOM forest algorithms ,GENETIC markers ,GENE expression profiling ,QUESTIONNAIRES ,FACTOR analysis ,RESEARCH funding ,CLUSTER analysis (Statistics) ,HEADACHE ,WOMEN'S health ,LONGITUDINAL method ,ALGORITHMS ,EPIGENOMICS - Abstract
Background: Several studies have described potential microRNA (miRNA) biomarkers associated with migraine, but studies are scarcely reproducible primarily due to the heterogeneous variability of participants. Increasing evidence shows that disease-related intrinsic factors together with lifestyle (environmental factors), influence epigenetic mechanisms and in turn, diseases. Hence, the main objective of this exploratory study was to find differentially expressed miRNAs (DE miRNA) in peripheral blood mononuclear cells (PBMC) of patients with migraine compared to healthy controls in a well-controlled homogeneous cohort of non-menopausal women. Methods: Patients diagnosed with migraine according to the International Classification of Headache Disorders (ICHD-3) and healthy controls without familial history of headache disorders were recruited. All participants completed a very thorough questionnaire and structured-interview in order to control for environmental factors. RNA was extracted from PBMC and a microarray system (GeneChip miRNA 4.1 Array chip, Affymetrix) was used to determine the miRNA profiles between study groups. Principal components analysis and hierarchical clustering analysis were performed to study samples distribution and random forest (RF) algorithms were computed for the classification task. To evaluate the stability of the results and the prediction error rate, a bootstrap (.632 + rule) was run through all the procedure. Finally, a functional enrichment analysis of selected targets was computed through protein–protein interaction networks. Results: After RF classification, three DE miRNA distinguished study groups in a very homogeneous female cohort, controlled by factors such as demographics (age and BMI), life-habits (physical activity, caffeine and alcohol consumptions), comorbidities and clinical features associated to the disease: miR-342-3p, miR-532-3p and miR-758-5p. Sixty-eight target genes were predicted which were linked mainly to enriched ion channels and signaling pathways, neurotransmitter and hormone homeostasis, infectious diseases and circadian entrainment. Conclusions: A 3-miRNA (miR-342-3p, miR-532-3p and miR-758-5p) novel signature has been found differentially expressed between controls and patients with migraine. Enrichment analysis showed that these pathways are closely associated with known migraine pathophysiology, which could lead to the first reliable epigenetic biomarker set. Further studies should be performed to validate these findings in a larger and more heterogeneous sample. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
12. An Innovative JavaScript-Based Framework for Teaching Backtracking Algorithms Interactively.
- Author
-
Nasralla, Moustafa M.
- Subjects
JAVASCRIPT programming language ,ALGORITHMS ,CONCEPT learning ,ENGINEERING education ,EIGENFUNCTIONS ,DIGITAL learning - Abstract
Algorithm fundamentals are useful to learn at different levels engineering education. One of the most difficult concepts to teach and understand is backtracking algorithms with proper bounding functions. This article proposes a framework to implement interactive online tools showing examples of backtracking algorithms in which students can graphically observe execution step-by-step. This approach is illustrated with the n-queens problem with students from Prince Sultan University, Saudi Arabia, and Complutense University of Madrid, Spain. The results show 6.67% increased learning on a backtracking exercise in the experimental group over the control group, in which the algorithms were automatically validated with DOMjudge software (an automated system used to run programming contests). The proposed framework was evaluated as easy to use, with a score of 74.5% in the validated System Usability Scale (SUS); easy to learn, with a score of 6.22 out of 7 in the validated Usefulness, Satisfaction, and Ease-of-Use (USE) scale; and with a general satisfaction of 5.97 out of 7 in the validated USE scale. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
13. A New Methodology to Study Street Accessibility: A Case Study of Avila (Spain).
- Author
-
Curado, Manuel, Rodriguez, Rocio, Jimenez, Manuel, Tortosa, Leandro, and Vicent, Jose F.
- Subjects
ALGORITHMS ,MUNICIPAL services ,ECONOMIC models ,ECONOMIC impact ,FACTOR structure ,STREETS ,LOCAL transit access - Abstract
Taking into account that accessibility is one of the most strategic and determining factors in economic models and that accessibility and tourism affect each other, we can say that the study and improvement of one of them involved the development of the other. Using network analysis, this study presents an algorithm for labeling the difficulty of the streets of a city using different accessibility parameters. We combine network structure and accessibility factors to explore the association between innovative behavior within the street network, and the relationships with the commercial activity in a city. Finally, we present a case study of the city of Avila, locating the most inaccessible areas of the city using centrality measures and analyzing the effects, in terms of accessibility, on the commerce and services of the city. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.