Choice of Metrics used in Collaborative Filtering and their Impact on Recommender Systems

The capacity of recommender systems to make correct predictions is essentially determined by the quality and suitability of the collaborative filtering that implements them. The common memory-based metrics are Pearson correlation and cosine, however, their use is not always the most appropriate or sufficiently justified. In this paper, we analyze these two metrics together with the less common mean squared difference (MSD) to discover their advantages and drawbacks in very important aspects such as the impact when introducing different values of k-neighborhoods, minimization of the MAE error, capacity to carry out a sufficient number of predictions, percentage of correct and incorrect predictions and behavior when attempting to recommend the n-best items. The paper lists the results and practical conclusions that have been obtained after carrying out a comparative study of the metrics based on 135 experiments on the MovieLens database of 100,000 ratios

Economic evaluation of small desalination plants from brackish aquifers. Application to Campo de Cartagena (SE Spain)

The Campo de Cartagena (Eastern Spain) is one of Europe’s driest areas with a mean precipitation of around 300 mm. One of the main challengesin the region is to secure a reliable water supply in both quantity and quality terms, to provide a water supply and agricultural irrigation, while water desalination has become an extensively applied solution, and one of the most sustainable solutions to the water scarcity problem. As water availability is lacking and groundwater quality is poor, the agricultural sector in Campo de Cartagena has developed small private brackish groundwater desalination plants (15-20 m3/h) through already existing agricultural wells. Costs and benefits (C-B) for citrus cultivation (1 ha) in three such plants have been assessed. The results indicate that for the studied cases, current agricultural management is feasible and costs outweigh benefits, with a positive NPV and a cost/benefit ratio higher than 1. The internal rate of return is also positive and higher than 11%. The results evidence practical and theoretical implications as to how to increase water resources in areas where water is scarce by closing the loop, ensuring farmers’ profitability and encouraging private sector investments.Peer ReviewedPostprint (author's final draft

Qualidade Físico-química E Sensorial De Genótipos De Banana

Despite the diversity of banana varieties in Brazil, only a few cultivars have the proper agronomic traits and fruit quality for commercial exploitation. This study aimed at evaluating the physicochemical traits and sensorial acceptance of banana genotypes, in order to identify those with potential for commercial growing. Six improved banana genotypes were assessed (BRS Maravilha, PC 0101, FHIA 18, TM 2803, YB 4203 and BRS Caipira), as well as three commercial cultivars (Grand Naine, Pacovan and Prata Anã). Analyses of peel and pulp color, peel thickness, pulp yield, moisture, pH, soluble solids, titratable acidity, total carotenoids and sensorial acceptance were performed. The BRS Maravilha, FHIA 18, YB 4203 and BRS Caipira genotypes presented physicochemical traits similar to the Grand Naine, Pacovan and Prata Anã commercial cultivars. The BRS Maravilha and TM 2803 genotypes had sensorial acceptance similar to the Prata Anã and Grand Naine cultivars, and are therefore promising for commercial growing, with the advantage of being resistant to the black Sigatoka and Panama disease. © 2016, Universidade Federal De Goias (UFG). All Rights Reserved.461899

What happened to my plastids? - Persistence of functionality in diatom plastids stolen by grazer intertidal benthic foraminifera

International audienc

Good character at college: the combined role of second-order character strength factors and phronesis motivation in undergraduate academic outcomes

A renewed interest in the study of character and virtue has recently emerged in the fields of Education and Psychology. The latest research has confirmed the association between virtuous consistent behaviours and academic positive outcomes. However, the motivational dimension of character (the intentions underlying the patterns of observed behaviours) has received little attention. This research aims to extend the knowledge on this topic by examining the predictive relationships between the behavioural and motivational dimensions of character, with reference to academic engagement, career self-doubt and performance of Spanish university students. A total of 183 under- graduates aged 18–30 (142 of whom were women) from the north of Spain completed specific parts of self-report questionnaires, including the Values in Action VIA-72, a Spanish translated and validated version of the Moral Self-Relevance Measure MSR, and the Utrecht Work Engagement Student Scale UWES-S9. The collected data were analysed using Structural Equation Modelling. The behavioural dimension of character (character strength factors of caring, self-control and inquisitiveness) showed positive associations with academic engagement and performance. The motivational dimension of character (phronesis motivation), was negatively related to career self-doubt. For the first time, the present study has provided support for the contribution of both dimensions of character to undergraduate academic outcomes

Shrinkage and mechanical performance of geopolymeric mortars based on calcined Tunisian clay

Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry. Since the majority of the existent infrastructures are Portland cement concrete based this means that concrete infrastructure rehabilitation is a hot issue to be dealt with. Geopolymers are novel inorganic binders with high potential to replace Portland cement based ones. Geopolymerization is a complex chemical process evolving various aluminosilicate oxides with silicates under highly alkaline conditions, yielding polymeric units, similar to those of an aluminosilicate glass. So far very few studies in the geopolymer field have addressed the rehabilitation of deteriorated concrete structures. This paper discloses some results of an investigation concerning the development geopolymeric repair mortars based on a calcined Tunisian clay. The results show that Tunisian calcined clay based mortars have hydration products with typical geopolymeric phases. Results also show that the geopolymeric mortar shows a high unrestrained shrinkage behavior and that its modulus of elasticity is below the threshold required for this repair mortars

A policy-based containerized filter for secure information sharing in organizational environments

In organizational environments, sensitive information is unintentionally exposed and sent to the cloud without encryption by insiders that even were previously informed about cloud risks. To mitigate the effects of this information privacy paradox, we propose the design, development and implementation of SecFilter, a security filter that enables organizations to implement security policies for information sharing. SecFilter automatically performs the following tasks: (a) intercepts files before sending them to the cloud; (b) searches for sensitive criteria in the context and content of the intercepted files by using mining techniques; (c) calculates the risk level for each identified criterion; (d) assigns a security level to each file based on the detected risk in its content and context; and (e) encrypts each file by using a multi-level security engine, based on digital envelopes from symmetric encryption, attribute-based encryption and digital signatures to guarantee the security services of confidentiality, integrity and authentication on each file at the same time that access control mechanisms are enforced before sending the secured file versions to cloud storage. A prototype of SecFilter was implemented for a real-world file sharing application that has been deployed on a private cloud. Fine-tuning of SecFilter components is described and a case study has been conducted based on document sharing of a well-known repository (MedLine corpus). The experimental evaluation revealed the feasibility and efficiency of applying a security filter to share information in organizational environmentsThis work has been partially supported by the Spanish “Ministerio de Economia y Competitividad” under the project grant TIN2016-79637-P “Towards Unification of HPC and Big Dataparadigms”

A containerized service for clustering and categorization of weather records in the cloud

This paper presents a containerized service for clustering and categorization of weather records in the cloud. This service considers a scheme of microservices and containers for organizations and end-users to manage/process weather records from the acquisition, passing through the prepossessing and processing stages, to the exhibition of results. In this service, a specialized crawler acquires records that are delivered to a microservice of distributed categorization of weather records, which performs clustering of acquired data (the temperature and precipitation) by spatiotemporal parameters. The clusters found are exhibited in a map by a geoportal where statistic microservice also produce results regression graphs on-the-fly. To evaluate the feasibility of this service, a case study based on 33 years of daily records captured by the Mexican weather station network (EMAS-CONAGUA) has been conducted. Lessons learned in this study about the performance of record acquisition, clustering processing, and mapping exhibition are described in this paper. Examples of utilization of this service revealed that end-users can analyze weather parameters in an efficient, flexible and automatic manner.This work was partially supported by the sectoral fund of research, technological development and innovation in space activities of the Mexican National Council of Science and Technology (CONACYT) and the Mexican Space Agency (AEM), project No.262891

Multimodal interaction on english testing academic assessment

[EN] Multimodal interaction methods applied to learning environments of the English language will be a line for future research from the use of adapted mobile phones or PDAs. Today's mobile devices allow access and data entry in a synchronized manner through different channels. At the academic level we made the first analysis of English language learning on a multimodal experimental platform. The research will evaluate the impact of college students use for future online applications aimed at improving language skills through self-learning. (C) 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of Prof. Dr. Huseyin UzunboyluThis work was carried out through research conducted in the project: "Analysis and verification of adaptation and accessible multimodal interaction for language examinations on mobile devices". It has been funded by the Universitat Politècnica de València as part of the program: "Projects for new lines in multidisciplinary research PID-05-10".Magal Royo, T.; Giménez López, JL.; García Laborda, J. (2012). Multimodal interaction on english testing academic assessment. Procedia Social and Behavioral Sciences. 46:5824-5827. https://doi.org/10.1016/j.sbspro.2012.06.522S582458274

Action-emotion Style, Learning Approach, and Coping Strategies, in undergraduated University Students

El Estilo Acción-Emoción (EAE) es un constructo psicológico de tipo motivacional-afectivo referido a la motivación de logro, basado en el Patrón de Conducta tipo A (PCTA), característico de los alumnos, en interacción con situaciones de estrés. La combinación de la competitividad y la sobrecarga laboral, con las emociones de la impaciencia y hostilidad, conduce a una clasificación en cinco categorías de estilo de acciónemoción (Tipo B, tipo Impaciente-hostil, Tipo Medio, Tipo CompetitivoSobrecarga Laboral y Tipo A). El objetivo de la presente investigación fue establecer la relación entre las características del EAE con los enfoques de aprendizaje (enfoque profundo y enfoque superficial) y las estrategias de afrontamiento (centradas en la emoción y centradas en el problema). La muestra estuvo compuesta por 225 estudiantes del Programa de Licenciatura en Psicología. Se realizaron análisis de correlaciones bivariados de Pearson y análisis multivariados. Los resultados mostraron una asociación positiva y significativa de las características de la competitividad-sobrecarga con el enfoque profundo y las estrategias centradas en el problema, así como de la impaciencia-hostilidad con el enfoque superficial y las estrategias centradas en la emoción. El nivel de estilo de acción-emoción tuvo un efecto principal significativo. Los resultados obtenidos verifican las hipótesis planteadas referidas a la relación entre el estilo de acción-emoción, los enfoques de aprendizaje y las estrategias de afrontamiento