Value, quality, purchasing habits and repurchase intention in B2C: differences between frequent and occasional purchasers

Este estudio propone un modelo integrador de la recompra en comercio electrónico (B2C), basado en la teoría de la confirmación de expectativas, tomando como partida el modelo de Bhattacherjee extendido con el modelo de satisfacción Cronin. El modelo de investigación se ha probado con 536 compradores españoles, usando análisis multigrupo. El modelo fue capaz de explicar más del setenta por ciento de la varianza de la intención de recompra. Como resultados, la relación entre la calidad y la satisfacción es no significativa para todos los tipos de consumidores y la relación entre la utilidad y la recompra es no significativa sólo para los compradores más frecuentes. Algunas ideas para llevar a la práctica son presentadas a modo de discusión

The ASSERT Virtual Machine Kernel: Support for preservation of temporal properties.

The ASSERT Project1 is aimed at defining new software engineering methods and tools for the development of critical embedded real-time systems in the aerospace domain. One of its main achievements is a new model-driven software process, which is based on the concept of property-preserving model transformations. Functional models developed with appropriate tools for the application domain are embedded in containers defining component interfaces and non-functional (e.g. timing) properties in a platform-independent set of notations. The resulting model is then automatically transformed to a platform-specific model using deployment information on target computer nodes, communication channels, and software platforms. Finally, source code for each computer node is automatically generated from the platform-specific model. The key element of the ASSERT process is that non-functional properties must be preserved during all phases of model transformations. In order to ensure that properties are preserved in model transformations and that the different views of each model are consistent with each other, a common meta-model has been defined which provides a formal basis to the whole process. This meta-model is called the Ravenscar Computational Model (RCM)

Communication Paradigms for High-Integrity Distributed Systems with Hard Real-Time Requirements

The development and maintenance of high-integrity software is very expensive, and a specialized development process is required due to its distinctive characteristics. Namely, safety-critical systems usually execute over a distributed embedded platform with few hardware resources which must provide real-time communication and fault-tolerance. This work discusses the adequate communication paradigms for high-integrity distributed applications with hard real-time requirements, and proposes a restricted middleware based on the current schedulability theory which can be certified and capable to obtain the required predictability and timeliness of this kind of systems

A New Approach to Memory Partitioning in On-board Spacecraft Software. In Fabrice Kordon and Tullio Vardanega (eds.), Reliable Software Technologies

The current trend to use partitioned architectures in on-board spacecraft software requires applications running on the same computer platform to be isolated from each other both in the temporal and memory domains. Memory isolation techniques currently used in Integrated Modular Avionics for Aeronautics usually require a Memory Management Unit (MMU), which is not commonly available in the kind of processors currently used in the Space domain. Two alternative approaches are discussed in the paper, based on some features of Ada and state-of-the art compilation tool-chains. Both approaches provide safe memory partitioning with less overhead than current IMA techniques. Some footprint and performance metrics taken on a prototype implementation of the most flexible approach are included

Effectiveness of an mHealth intervention combining a smartphone app and smart band on body composition in an overweight and obese population: Randomized controlled trial (EVIDENT 3 study)

Background: Mobile health (mHealth) is currently among the supporting elements that may contribute to an improvement in health markers by helping people adopt healthier lifestyles. mHealth interventions have been widely reported to achieve greater weight loss than other approaches, but their effect on body composition remains unclear. Objective: This study aimed to assess the short-term (3 months) effectiveness of a mobile app and a smart band for losing weight and changing body composition in sedentary Spanish adults who are overweight or obese. Methods: A randomized controlled, multicenter clinical trial was conducted involving the participation of 440 subjects from primary care centers, with 231 subjects in the intervention group (IG; counselling with smartphone app and smart band) and 209 in the control group (CG; counselling only). Both groups were counselled about healthy diet and physical activity. For the 3-month intervention period, the IG was trained to use a smartphone app that involved self-monitoring and tailored feedback, as well as a smart band that recorded daily physical activity (Mi Band 2, Xiaomi). Body composition was measured using the InBody 230 bioimpedance device (InBody Co., Ltd), and physical activity was measured using the International Physical Activity Questionnaire. Results: The mHealth intervention produced a greater loss of body weight (–1.97 kg, 95% CI –2.39 to –1.54) relative to standard counselling at 3 months (–1.13 kg, 95% CI –1.56 to –0.69). Comparing groups, the IG achieved a weight loss of 0.84 kg more than the CG at 3 months. The IG showed a decrease in body fat mass (BFM; –1.84 kg, 95% CI –2.48 to –1.20), percentage of body fat (PBF; –1.22%, 95% CI –1.82% to 0.62%), and BMI (–0.77 kg/m2, 95% CI –0.96 to 0.57). No significant changes were observed in any of these parameters in men; among women, there was a significant decrease in BMI in the IG compared with the CG. When subjects were grouped according to baseline BMI, the overweight group experienced a change in BFM of –1.18 kg (95% CI –2.30 to –0.06) and BMI of –0.47 kg/m2 (95% CI –0.80 to –0.13), whereas the obese group only experienced a change in BMI of –0.53 kg/m2 (95% CI –0.86 to –0.19). When the data were analyzed according to physical activity, the moderate-vigorous physical activity group showed significant changes in BFM of –1.03 kg (95% CI –1.74 to –0.33), PBF of –0.76% (95% CI –1.32% to –0.20%), and BMI of –0.5 kg/m2 (95% CI –0.83 to –0.19). Conclusions: The results from this multicenter, randomized controlled clinical trial study show that compared with standard counselling alone, adding a self-reported app and a smart band obtained beneficial results in terms of weight loss and a reduction in BFM and PBF in female subjects with a BMI less than 30 kg/m2 and a moderate-vigorous physical activity level. Nevertheless, further studies are needed to ensure that this profile benefits more than others from this intervention and to investigate modifications of this intervention to achieve a global effect

Investigación y redes sociales en España. Observatorio de la difusión científico-tecnológica de los Organismos Públicos de Investigación en Redes Sociales

El desarrollo de la Web 2.0 y el auge de las redes sociales suponen un reto y a la vez una opor-tunidad única para el desarrollo y divulgación de la ciencia a sectores de la población tradicio-nalmente más alejados de los avances científicos. En España existen dos grupos de institucio-nes que conforman el tejido básico de investigación científica: Universidades y Organismos Públicos de Investigación (OPIs). Los OPIs son los grandes desconocidos para la sociedad, por lo que el estudio de sus políticas de difusión en redes sociales se antoja imprescindible para potenciar el fomento de la cultura científica en España y establecer un diálogo fluido entre ciencia y sociedad. Este libro introduce al lector en los diferentes OPIs españoles, dando a conocer los diferentes Centros e Institutos que los componen, sus principales líneas de investigación y su actividad en redes sociales. A través de un estudio sistemático de datos extraídos de las tres principa-les erdes sociales en importancia en la actualidad (Facebook, Twitter y YouTube), y técnicas de visualización de datos, el libro explora diferentes prácticas de uso de este tipo de redes para la difusión de la ciencia, y recopila una serie de mejores prácticas, complementadas con entrevistas a responsables de comunicación de los OPIs, Centros e Institutos que han logrado adoptar con más éxito estas nuevas tecnologías

Investigación y redes sociales en España. Observatorio de la difusión científico-tecnológica de los Organismos Públicos de Investigación en Redes Sociales

El desarrollo de la Web 2.0 y el auge de las redes sociales suponen un reto y a la vez una opor-tunidad única para el desarrollo y divulgación de la ciencia a sectores de la población tradicio-nalmente más alejados de los avances científicos. En España existen dos grupos de institucio-nes que conforman el tejido básico de investigación científica: Universidades y Organismos Públicos de Investigación (OPIs). Los OPIs son los grandes desconocidos para la sociedad, por lo que el estudio de sus políticas de difusión en redes sociales se antoja imprescindible para potenciar el fomento de la cultura científica en España y establecer un diálogo fluido entre ciencia y sociedad. Este libro introduce al lector en los diferentes OPIs españoles, dando a conocer los diferentes Centros e Institutos que los componen, sus principales líneas de investigación y su actividad en redes sociales. A través de un estudio sistemático de datos extraídos de las tres principa-les erdes sociales en importancia en la actualidad (Facebook, Twitter y YouTube), y técnicas de visualización de datos, el libro explora diferentes prácticas de uso de este tipo de redes para la difusión de la ciencia, y recopila una serie de mejores prácticas, complementadas con entrevistas a responsables de comunicación de los OPIs, Centros e Institutos que han logrado adoptar con más éxito estas nuevas tecnologías