An App Performance Optimization Advisor for Mobile Device App Marketplaces

On mobile phones, users and developers use apps official marketplaces serving as repositories of apps. The Google Play Store and Apple Store are the official marketplaces of Android and Apple products which offer more than a million apps. Although both repositories offer description of apps, information concerning performance is not available. Due to the constrained hardware of mobile devices, users and developers have to meticulously manage the resources available and they should be given access to performance information about apps. Even if this information was available, the selection of apps would still depend on user preferences and it would require a huge cognitive effort to make optimal decisions. Considering this fact we propose APOA, a recommendation system which can be implemented in any marketplace for helping users and developers to compare apps in terms of performance. APOA uses as input metric values of apps and a set of metrics to optimize. It solves an optimization problem and it generates optimal sets of apps for different user's context. We show how APOA works over an Android case study. Out of 140 apps, we define typical usage scenarios and we collect measurements of power, CPU, memory, and network usages to demonstrate the benefit of using APOA.Comment: 18 pages, 8 figure

Comprehension of Ads-supported and Paid Android Applications: Are They Different?

The Android market is a place where developers offer paid and-or free apps to users. Free apps are interesting to users because they can try them immediately without incurring a monetary cost. However, free apps often have limited features and-or contain ads when compared to their paid counterparts. Thus, users may eventually need to pay to get additional features and-or remove ads. While paid apps have clear market values, their ads-supported versions are not entirely free because ads have an impact on performance. In this paper, first, we perform an exploratory study about ads-supported and paid apps to understand their differences in terms of implementation and development process. We analyze 40 Android apps and we observe that (i) ads-supported apps are preferred by users although paid apps have a better rating, (ii) developers do not usually offer a paid app without a corresponding free version, (iii) ads-supported apps usually have more releases and are released more often than their corresponding paid versions, (iv) there is no a clear strategy about the way developers set prices of paid apps, (v) paid apps do not usually include more functionalities than their corresponding ads-supported versions, (vi) developers do not always remove ad networks in paid versions of their ads-supported apps, and (vii) paid apps require less permissions than ads-supported apps. Second, we carry out an experimental study to compare the performance of ads-supported and paid apps and we propose four equations to estimate the cost of ads-supported apps. We obtain that (i) ads-supported apps use more resources than their corresponding paid versions with statistically significant differences and (ii) paid apps could be considered a most cost-effective choice for users because their cost can be amortized in a short period of time, depending on their usage.Comment: Accepted for publication in the proceedings of the IEEE International Conference on Program Comprehension 201

¿Fue la colectivización realmente necesaria? Aportes recientes a un prolongado debate

This paper proposes the revision of the last contributions to the long debate linked with the collectivization of the soviet agriculture ordered by stalin in 1929. Beyond the appalling social consequences, also object of historiographical debates, we discussed if his objective, the creation of collective farms destined to the modernization of the country, effectively fulfilled that function.El artículo propone la revisión de las últimas aportaciones al largo debate vinculado con la colectivización de la agricultura soviética ordenada por Stalin en 1929. Más allá de las pavorosas consecuencias sociales, objeto también de polémica historiográfica, se discute si su objetivo, la creación de granjas colectivas destinadas a contribuir a la modernización del país, cumplieron efectivamente esa función

A-GWASF-GA: The New Version of GWASF-GA to Solve Many Objective Problems

A new version of the evolutionary algorithm based on GWASF-GA [1] is proposed in this work. GWASF-GA is an aggregation-based algorithm which uses the Tchebychev metric plus an augmentation term as fitness function and two reference points (the utopian and nadir points) to classify the individuals according to a set of widely-distributed weight vectors. Although this algorithm obtains a good approximation of the Pareto front (PF) for multi-objective optimization problems, this may be more difficult to obtain for many-objective optimization problems due to the fact that the weight vectors used are never updated along the search process. For this reason, we propose a new version of the algorithm, called A-GWASF-GA, in which a dynamic adjustment of the weight vectors is carried out. The main idea is to re-calculate some weight vectors in order to obtain solutions in parts of the PF with a lack of solutions. Firstly, a percentage (p) of the total number of evaluations is performed with the original GWASF-GA [1]. Secondly, during the rest of evaluations (1-p), we re-calculate na times the projection directions determined by a subset of Na weight vectors. The re-calculation process is based on a scattering level, a measure based on the distance of each solution and the solutions around it. According to the scattering level of the generated solutions, we detect the Na weight vectors projecting toward overcrowded areas of the PF and we re-calculate them so that their new projection directions point towards areas of the PF which are not so well approximated. In order to show the effectiveness of A-GWASF-GA, we compare it with NSGA-III [2, 3], MOEA/D [4], MOEA/D-AWA [5] and the original GWASF-GA.To evaluate their performance, we use the IGD metric [6]. The results of the computational experiment demonstrate the good performance of A-GWASF-GA in the novel many-objective optimization benchmark problems considered.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Childhood, poverty and economic crisis

Colección ReSed. Es un artículo de ReSed Nº 3, perteneciente al monográfico Crisis Social, Educación y Desarrollo Profesional. Coordinación del Monográfico: Dra. Montserrat Vargas Vergara Dirección de ReSed: Dra. A-Beatriz Pérez-GonzálezEsta reseña analiza el libro que facilita la autora Sara Ayllón. En él se presenta el análisis de las dinámicas de la pobreza, examinando hasta qué punto los hogares con niños-as que están en esta situación son capaces de salir de ella

Control of "Conyza" and "Lolium" resistant to glyphosate

Con el fin de frenar y aportar soluciones a los problemas de resistencias a glifosato, aparecidos en los últimos años en algunas poblaciones de “Conyza” y “Lolium” en campos de olivar y cítricos, se establecieron 8 ensayos en “Conyza” y 7 en “Lolium” durante los años 2012 y 2013. En estos ensayos se evaluaron distintas materias activas que podrían emplearse en la rotación de herbicidas en estos cultivos. El control químico se realizó en el estadio de roseta para la “Conyza” y en el de 3-6 hojas para el “Lolium”. Las materias activas que mejor se comportaron fueron MCPA, fluroxipir, iodosulfuron, flazasulfuron y glufosinato para Conyza, y Flazasulfuron, Iodosulfuron, y quizalofop para “Lolium”.In order to slow down and provide solutions to the problems of resistance to glyphosate that have appeared during last years in some populations of “Conyza” and “Lolium” in olive and citrus fields, 8 trials in “Conyza” and 7 in “Lolium” were performed during the years 2012 and 2013. In these trials different active ingredients that could be used in the herbicides rotation in these crops were evaluated. Chemical control was performed at the rosette stage for “Conyza” and the 3-6 leaves for “Lolium”. The active substances that performed better were MCPA, fluroxypyr, iodosulfuron, flazasulfuron and glufosinate for “Conyza”, and flazasulfuron, iodosulfuron, and quizalofop for “Lolium.

Distribution, abundance and biomass trends of the genus Sebastes on Flemish cap (division 3M)

12 páginas, 11 figuras.-- Scientific Council Meetin