373 research outputs found
Herramienta de apoyo a la docencia de algoritmos de selección de instancias
En el currículo de ingeniería informática la minería
de datos y el aprendizaje automático son cada
vez más relevantes, tanto en los cursos de grado y
máster, como también en los de doctorado. Prueba
de ello es la aparición de diversas herramientas que
facilitan el aprendizaje de algoritmos relacionados
con la disciplina, mediante la ejecución paso a paso
de los mismos y la visualización de los resultados.
Sin embargo, para el caso concreto de los algoritmos
de selección de instancias, estas herramientas
son prácticamente inexistentes.
En el presente recurso docente se presenta una
herramienta implementada para cubrir esta carencia.
«Instance Selection», que es como se llama
la aplicación, está preparada para mostrar el funcionamiento
tanto de los algoritmos clásicos como
alguno de los más modernos, permitiendo la ejecución
paso a paso y visualizando los resultados intermedios
para facilitar la labor didáctica.
Las principales ventajas de la aplicación descrita
en este recurso docente son: que implementa varios
algoritmos, lo que permite su comparación, es multiplataforma,
permite la visualización incremental de
los pasos de los algoritmos implementados, la interfaz
está preparada para varios idiomas e incluye una
completa ayuda.SUMMARY -- In computer engineering curricula Data Mining and
Machine Learning are increasingly important in both
undergraduate and masters, as well as the PhD
courses. The emergence of several tools that facilitate
learning algorithms related to the discipline
proves that. Some of these tools allow the execution
of algorithms step by step showing the results of
each step, others let the student change the algorithm
parameters and the student can visualize the results.
However, for the specific case of instance selection
algorithms these tools are virtually nonexistent.
This paper discusses a tool implemented to fill
this gap. “Instance Selection”, which is the name of
the application, is prepared to show the operation of
both classical instance selection algorithms as some
of the most modern, allowing the execution step by
step and displaying the intermediate results to facilitate
the teaching task.
The main advantages of the application described
in this teaching resource are that it implements several
algorithms, allowing comparison between them,
it is multi-platform, it allows the interactive visualization
of the steps of the implemented algorithms,
the interface is ready for several languages, it includes
comprehensive help.Peer Reviewe
Collection and integration of local knowledge and experience through a collective spatial analysis
This article discusses the convenience of adopting an approach of Collective Spatial Analysis in the P/PGIS processes, with the aim of improving the collection and integration of knowledge and local expertise in decision-making, mainly in the fields of planning and adopting territorial policies. Based on empirical evidence, as a result of the review of scientific articles from the Web of Science database, in which it is displayed how the knowledge and experience of people involved in decision-making supported by P/PGIS are collected and used, a prototype of a WEB-GSDSS application has been developed. This prototype allows a group of people to participate anonymously, in an asynchronous and distributed way, in a decision-making process to locate goods, services, or events through the convergence of their views. Via this application, two case studies for planning services in districts of Ecuador and Italy were carried out. Early results suggest that in P/PGIS local and external actors contribute their knowledge and experience to generate information that afterwards is integrated and analysed in the decision-making process. On the other hand, in a Collective Spatial Analysis, these actors analyse and generate information in conjunction with their knowledge and experience during the process of decision-making. We conclude that, although the Collective Spatial Analysis approach presented is in a subjective and initial stage, it does drive improvements in the collection and integration of knowledge and local experience, foremost among them is an interdisciplinary geo-consensusPeer ReviewedPostprint (published version
Geospatial system of collective intelligence: A technological application for the interdisciplinary study of the geographical space complexity
Postprint (published version
Differences in pedalling technique between road cyclists of different competitive levels
P. 1619-1626El propósito de este estudio fue comparar la técnica de pedaleo en ciclistas de carretera de diferentes niveles competitivos. Once profesionales, trece élites y catorce clubes ciclistas fueron evaluados al comienzo de su temporada de competición. Se registraron las características antropométricas de los ciclistas y las mediciones de la bicicleta. Se realizaron tres series de pedaleo (200, 250, 300 W) en un cicloergómetro que simulaba su postura de ciclismo habitual a una cadencia constante (~ 90 rpm), mientras que se registraron las variables cinética y cinemática. Los resultados no mostraron diferencias en las principales variables antropométricas y mediciones de la bicicleta. Los ciclistas profesionales obtuvieron una mayor proporción de impulsos positivos (1.5-3.3% yp <0.05), principalmente debido a un menor esfuerzo de torsión durante la carrera ascendente (15.4-28.7% yp <0.05). También mostraron una mayor amplitud de movimiento del tobillo (ROM, 1.1-4.0º yp <0.05). Se encontraron correlaciones significativas (p <0.05) entre la masa corporal de los ciclistas y las variables cinéticas del pedaleo: proporción de impulso positivo (r = -0.59 - -0.61), mínimo (r = -0.59 - -0.63) y pares máximos (r = 0,35 - 0,47). En conclusión, los ciclistas profesionales tenían una mejor técnica de pedaleo que los ciclistas de élite y de clubes, porque optaron por aumentar la fuerza de tracción en la fase de recuperación para mantener la misma potencia de salida. Esta técnica depende de la experiencia en ciclismo y el nivel de experienci
Distribution of flumequine in intestinal contents and colon tissue in pigs after its therapeutic use in the drinking water
[EN] Flumequine concentrations in plasma, colon tissue and intestinal contents were evaluated in 12 healthy pigs after oral administration (12 mg/kg every 24 h for 5 consecutive days in drinking water). Plasma, colon tissue and intestinal content samples were collected from animals sacrificed on days 3, 6 and 7. Concentrations were measured by high performance liquid chromatography after having validated the method, following the European Medicines Agency (EMA) requirements. The drug was not detected in any plasma sample. In colon tissue, concentrations were higher on day 3 (0.230 ± 0.033 µg/g, descending colon; 0.156 ± 0.093 µg/g, ascending colon) than on day 6 (0.187 ± 0.123 µg/g, descending colon; 0.107 ± 0.007 µg/g, ascending colon). Concentrations were considerably higher in intestinal contents, again on day 3 (1.349 ± 1.401 µg/g, descending colon; 0.591 ± 0.209 µg/g, ascending colon) than on days 6 (0.979 ± 0.346 µg/g, descending colon; 0.595 ± 0.075 µg/g, ascending colon) and 7 (0.247 ± 0.172 µg/g, descending colon; 0.172 ± 0.086 µg/g, ascending colon). Measured concentrations were lower than those effective against the most common intestinal pathogenic microorganisms in swine and, more specifically, Brachyspira hyodysenteriae.SIThis research was funded by Laboratorios Syva S.A.U
Optimizing different loss functions in multilabel classifications
Multilabel classification (ML) aims to assign a set of labels to an instance. This generalization of multiclass classification yields to the redefinition of loss functions and the learning tasks become harder. The objective of this paper is to gain insights into the relations of optimization aims and some of the most popular performance measures: subset (or 0/1), Hamming, and the example-based F-measure. To make a fair comparison, we implemented three ML learners for optimizing explicitly each one of these measures in a common framework. This can be done considering a subset of labels as a structured output. Then, we use structured output support vector machines tailored to optimize a given loss function. The paper includes an exhaustive experimental comparison. The conclusion is that in most cases, the optimization of the Hamming loss produces the best or competitive scores. This is a practical result since the Hamming loss can be minimized using a bunch of binary classifiers, one for each label separately, and therefore, it is a scalable and fast method to learn ML tasks. Additionally, we observe that in noise-free learning tasks optimizing the subset loss is the best option, but the differences are very small. We have also noticed that the biggest room for improvement can be found when the goal is to optimize an F-measure in noisy learning task
Strategies to evaluate biodegradability: Application to chlorinated herbicides
The biodegradability of nitrochlorinated (diuron and atrazine) and chlorophenoxy herbicides (2,4-D and MCPA) has been studied through several bioassays using different testing times and biomass/substrate ratios. A fast biodegradability test using unacclimated activated sludge yielded no biodegradation of the herbicides in 24 h. The inherent biodegradability test gave degradation percentages of around 20-30 % for the nitrochlorinated herbicides and almost complete removal of the chlorophenoxy compounds. Long-term biodegradability assays were performed using sequencing batch reactor (SBR) and sequencing batch membrane bioreactor (SB-MBR). Fixed concentrations of each herbicide below the corresponding EC50 value for activated sludge were used (30 mg L-1 for diuron and atrazine and 50 mg L-1 for 2,4-D and MCPA). No signs of herbicide degradation appeared before 35 days in the case of diuron and atrazine and 21 days for 2,4-D, whereas MCPA was partially degraded since the early stages. Around 25-36 % degradation of the nitrochlorinated herbicides and 53-77 % of the chlorophenoxy ones was achieved after 180 and 135 days, respectively, in SBR, whereas complete disappearance of 2,4-D was reached after 80 days in SB-MBRAcknowledgments This work was supported by the Spanish Ministerio de Ciencia e Innovación through the projects CTM2010-15682 and CTQ2008-03988. S Sanchis wishes to thank the Ministerio de Ciencia e Innovación for a research grant
Coupling Fenton and biological oxidation for the removal of nitrochlorinated herbicides from water
The combination of Fenton and biological oxidation for the removal of the nitrochlorinated herbicides alachlor, atrazine and diuron in aqueous solution has been studied. The H2O2 dose was varied from 20 to 100% of the stoichiometric amount related to the initial chemical oxygen demand (COD). The effluents from Fenton oxidation were analyzed for ecotoxicity, biodegradability, total organic carbon (TOC), COD and intermediate byproducts. The chemical step resulted in a significant improvement of the biodegradability in spite of its negligible or even slightly negative effect on the ecotoxicity. Working at 60% of the stoichiometric H2O2 dose allowed obtaining highly biodegradable effluents in the cases of alachlor and atrazine. That dose was even lower (40% of the stoichiometric) for diuron. The subsequent biological treatment was carried out in a sequencing batch reactor (SBR) and the combined Fenton-biological treatment allowed up to around 80% of COD reductionThis work was supported by the Spanish MCINN through the projects CTM2010-15682 and CTQ2008-03988. S. Sanchis wishes to thank the MCINN for a research gran
Improvement of albendazole bioavailability with menbutone administration in sheep
[EN] The pharmacokinetic interaction between a benzimidazole (albendazole, ABZ) and a choleretic drug (menbutone, MEN) was evaluated in sheep. The plasma disposition of albendazole sulfoxide (ABZSO, active metabolite) and albendazole sulfone (ABZSO2, inactive metabolite) was investigated following an oral administration of albendazole (ABZ) (5 mg/kg) alone or with menbutone (MEN) (intramuscular, 10 mg/kg). Blood samples were collected over 3 days post-treatment, and drug plasma concentrations were measured by high performance liquid chromatography (HPLC). ABZSO was measured from 0.5 to 48 h, and ABZSO2 from 2 to 60 h. No parent drug was detected at any sampling time. Mean maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC) were 12.8% and 21.5% higher for ABZSO when ABZ and MENwere administered together, which indicates a significant increase in the amount absorbed. The rate of absorption was not modified, with similar values for the time to reach Cmax (tmax) (11.5 h with ABZ + MEN and 10.7 h with ABZ treatment), although no significant differences were observed for these latter pharmacokinetic parameters. Regarding ABZSO2, Cmax, AUC and tmax values were similar after both treatments (ABZ or ABZ + MEN). The results obtained indicate that co-administration of ABZ and MEN may be an interesting and practical option to increase the efficacy of this anthelmintic.S
Determination of Menbutone: Development and Validation of a Sensitive HPLC Assay according to the European Medicines Agency Guideline
[EN] Menbutone is often used to stimulate the hepato-digestive activity in case of digestive disorders and hepatic insufficiency in different species (cattle, sheep, goats, pigs, horses, dogs) because it has choleretic and cholagogue effects and increases gastric and pancreatic juices. The objective was to develop and validate an HPLC method to quantify menbutone in sheep plasma using sparfloxacin as internal standard. The HPLC mobile phase consisted of acetonitrile:monopotassium phosphate solution. The method was validated according to EMA guideline (EMEA/CHMP/EWP/192217/2009). Mean retention times of menbutone and sparfloxacin were 4.5 and 2.2 min, respectively. The method met all specifications of the EMA guideline, being selective and linear in the range of 0.2–100 g/mL (R2 0.99). The within-run precision range was 0.19–8.21%, with an accuracy of 102.99–119.52% for the lower limit of quantitation (LLOQ). For the other values (LOW, MED, HIGH) the precision range was 0.01–4.77%, with an accuracy of 85.17–109.67%. The LLOQ was 0.2 g/mL, and no interference from the biological matrix was found. Stability of menbutone in the biological matrix at different storage conditions was also demonstrated. Thus, the method can be used to determine menbutone concentrations in plasma sheep in different types of studiesS
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