Requirements Engineering in the Development Process of Web Systems: A Systematic Literature Review

Requirements Engineering (RE) is the first phase in the software development process during which designers attempt to fully satisfy users’ needs. Web Engineering (WE) methods should consider adapting RE to the Web’s large and diverse user groups. The objective of this work is to classify the literature with regard to the RE applied in WE in order to obtain the current “state-of-the-art”. The present work is based on the Systematic Literature Review (SLR) method proposed by Kitchenham; we have reviewed publications from ACM, IEEE, Science Direct, DBLP and World Wide Web. From a population of 3059 papers, we identified 14 primary studies, which provide information concerning RE when used in WE methods.This work has been partially supported by the Programa de Fomento y Apoyo a Proyectos de Investigación (PROFAPI) from the Universidad Autónoma de Sinaloa (México), and the MANTRA project (GRE09-17) from the University of Alicante, Spain, and GV/2011/035 from the Valencia Government

Sistema motivacional alternativo

PDFLa Gestión Educativa, el Rendimiento Académico de los y las estudiantes de la Unidad Educativa “Bíblica Cristiana Sendero de Fe”, y un sistema Motivacional Alternativo que permita integrarlos junto a los docentes, directivos y padres de familia de la Institución, es de suma importancia debido a que el grado de motivación de un estudiante permite aumentar el interés sobre las actividades de su propio aprendizaje o las acciones que lo conducen a lograr ese objetivo. La motivación tiene una relación estrecha con el rendimiento académico (Javier J. Maquilón Sánchez y Fuensanta Hernández Pina, 2011). Se desea tener educandos con un alto nivel de autoestima que les permita auto motivarse y con esto mejorar su actitud hacia los estudios, logrando resultados de excelencia académica, considerando además que la influencia del entorno sobre ellos es la clave para un mayor desempeño. Por lo tanto el análisis está dirigido a la investigación de todo el alumnado, los docentes, los directivos y padres de familia de la entidad, tomando en cuenta que la calidad educativa tiene que ser revisada de forma integral. Cabe resaltar que en la actualidad, es evidente que entre los actores de la educación existe una gran apatía con respecto al rendimiento académico y que poco o nada importan las buenas calificaciones, afectando de gran manera nuestra imagen institucional. La estrategia fundamental sería incrementar, fomentar y mejorar la forma en que se motiva a los y las estudiantes para que estos tengan un mayor grado de interés hacia el estudio, de tal forma que el maestro aprenda el lenguaje para estimular su autoestima para que de esta manera, se fijen metas de estudio importantes, reduciendo así el porcentaje de bajas calificaciones y supletorios, lo que permitirá seguir ofertando una educación personalizada eficiente y de calidad.The educational management, the academic performance of the students of the Unidad Educativa "Biblica Cristiana Sendero de Fe" and a motivational system that permits integration with teachers, administrators and parents of the institution is very important because the motivation of a student can increase the interest on their own learning activities or actions that lead to achieving this goal. Motivation has a direct relationship to academic achievement Javier j. Maquilón Sánchez & Fuensanta Hernández Pina, 2011). We want to have students with a high level of self-esteem that allows them to self motivate and improve their attitude towards studies, achieving academic excellence results, considering that environmental influence on them is the key to high performance. So the analysis is directed to the investigation of all students, teachers, managers and parents of the institution, knowing that the quality of education must be reviewed in all aspects It should be noted that at present, it is clear that among the actors of education there is great apathy in relation to educational performance and little or not care about good qualifications, affecting in great way our institutional image. The basic strategy is to increase, develop and improve the way in which it encourages the students so that they have a greater interest in the study, the teacher have to learn the language to stimulate their selfesteem so that in this way, they can set important study goals, also reducing the percentage of low grades and supplementary exams, allowing us to continue offering a personalized education with efficiency and quality.Instituto de Pos-Grado y Educación Contínua; Maestría en Gerencia Educativ

The Role of Negative Affect in Emotional Processing of Food-Related Images in Eating Disorders and Obesity

The aim of the present study was to analyze differences in the emotional processing (valence, arousal, and dominance) of food-related information in patients with eating disorders (ED), patients with obesity, and healthy women. Moreover, the mediator role of negative affect and the moderating role of the diagnostic group (ED vs. non-ED) were analyzed. Method: The sample consisted of 94 women (39 with eating disorders, 19 with obesity, and 36 healthy participants). Measures: International Affective Picture System (IAPS) food picture exposure task; Self-Assessment Manikin Analog-Visual Scale (SAM) appraising Arousal, Valence, and Dominance; Eating Attitudes Test (EAT-26); Positive and Negative Affect Schedule (PANAS). Results: Patients with purging symptomatology rated food images as more unpleasant than healthy women. Patients with purging and restrictive eating symptomatology showed higher levels of arousal and less dominance over the emotions experienced, compared to patients with obesity and healthy women. The mediation analysis showed that negative affect mediated the relationship between eating symptomatology (EAT-26) and the Valence of food images, as well as the control over the emotions experienced when viewing food images (Dominance). For the moderation analysis participants were regrouped into two groups (ED patients vs. non-ED patients). The direct relationship between eating symptomatology and food image valence was moderated by the diagnostic group. However, the group did not moderate the direct relationship between the EAT-26 and dominance over experienced emotions, or the indirect effect on eating symptomatology through negative affect. These results show the relevance of negative affect in the emotional processing of food-related information, and they support an eating disorder-disordered eating dimensional perspective.This study was supported by the Ministerio de Economia y Competitividad (MINECO) and the Fondo Europeo de Desarrollo Regional (FEDER) through the research project (PSI2014-51920-R)

An MDA approach for goal-oriented requirement analysis in Web engineering

Web designers usually ignore how to model real user expectations and goals, mainly due to the large and heterogeneous audience of the Web. This fact leads to websites which are difficult to comprehend by visitors and complex to maintain by designers. In order to ameliorate this scenario, an approach for using the i* modeling framework in Web engineering has been developed in this paper. Furthermore, due to the fact that most of the existing Web engineering approaches do not consider how to derive conceptual models of the Web application from requirements analysis we also propose the use of MDA (Model Driven Architecture) in Web engineering for: (i) the definition of the requirements of a Web application in a Computational Independent Model (CIM), (ii) the description of Platform Independent Models (PIMs), and (iii) the definition of a set of QVT (Query/View/Transformation) transformations for the derivation of PIMs from requirements specification (CIM), thus to enable the automatic generation of Web applications. Finally, we include a sample of our approach in order to show its applicability and we describe a prototype tool as a proof of concept of our research.This work has been partially supported by the MANTRA project (GRE09-17) from the University of Alicante, and by the MESOLAP (TIN2010-14860) from the Spanish Ministry of Education and Science. José Alfonso Aguilar is subventioned by CONACYT (Consejo Nacional de Ciencia y Tecnología) Mexico and University of Sinaloa, Mexico

Inter-particle connections development during sintering of Cr-Mo-alloyed steel powder in N2/H2 atmosphere

Powder metallurgy is one of the oldest metal processing techniques; it is a manufacturing process that is based on the production of metal, ceramic or composite components from powders. Manufacturing of ferrous powder metallurgy precision parts has increased in the last decades, in particular for automotive applications. The properties of a component manufacture by PM techniques may be tailored or improved by the addition of alloying elements; chromium and molybdenum are widely used in conventional metallurgy as alloying elements, but the tendency of chromium to form stable oxides and the decrease in compressibility it produces, have restricted its use in powder metallurgy. However, low chromium alloyed steels meet all the requirements for most structural components and for the market needs, so research and development of these steels is being carried out nowadays. In this study, specimens of the same composition (pre-alloyed water atomized powder of low Cr-Mo content) were sintered in a 90N2/10H2 atmosphere during 3 minutes and at different temperatures from 700°C to 1120°C. Two additional samples were sintered at 1120°C during 15 and 30 minutes each. Impact test was performed in all the specimens in order to produce fracture surfaces, which were studied using High Resolution Scanning Electron Microscopy (HRSEM) and EDX analysis. Microstructural investigation was carried out as well. The objective of this investigation was to evaluate the effect of the sintering temperature and time on both the inter-particle necks development and the inclusions evolution. It was found that Inter-particle necks development is enhanced with sintering temperature and time and that the reduction of the Fe-oxide layer on the powder particles is a pre-condition for the formation of solid metallic contacts. Furthermore, different failure mechanisms were found with increasing sintering temperature. It was also found that the morphology and size of the inclusions change with increasing sintering temperature and time.---------------------------------------------------------------------------------------------La pulvimetalurgia es una de las técnicas de procesamiento de materiales metálicos más antiguas: consiste en un proceso de fabricación para la producción de componentes metálicos, cerámicos o de materiales compuestos a partir de polvos. La fabricación de piezas fabricadas a partir de polvos férreos se ha incrementado en las últimas décadas, en especial en la fabricación de elementos para la industria del automóvil. Las propiedades de un componente fabricado por PM pueden ser ajustadas o mejoradas mediante la adición de elementos de aleación: cromo y molibdeno han sido ampliamente utilizados en la metalurgia convencional como aleantes, pero la tendencia del cromo para formar óxidos de cromo muy estables y el decremento en compresibilidad que produce han limitado su uso en pulvimetalurgia. Sin embargo, los aceros aleados con bajo contenido en cromo cumplen todos los requerimientos necesarios para la mayoría de los componentes estructurales y para las necesidades del mercado, por lo que investigación y desarrollo de este tipo de aceros se está desarrollando en estos últimos años. En este estudio, probetas de la misma composición (polvos pre-aleados fabricados mediante atomización en agua con bajo contenido en cromo y molibdeno) fueron sinterizadas en atmósfera de 90N2/10H2 durante tres minutos y a diferentes temperaturas desde 700 hasta 1120ºC. Asimismo, dos probetas adicionales se sinterizaron a 1120ºC durante 15 y 30 minutos respectivamente. Las probetas fueron sometidas a ensayo de fractura para producir superficies de fractura, que fueron estudiadas mediante microscopía electrónica de barrido (SEM) y microscopía óptica. El objetivo de esta investigación fue evaluar el efecto de la temperatura y tiempo de sinterización en la evolución de los cuellos entre partículas y de las inclusiones. Se ha encontrado que el desarrollo de los cuellos entre partículas se ve incrementado con un aumento en la temperatura y el tiempo de sinterización y que la reducción de la capa superficial de óxido de hierro en las partículas es condición necesaria para la formación de contactos sólidos entre partículas. Además, se han encontrado diferentes mecanismos de fallo al aumentar la temperatura de sinterización. También ha podido comprobarse como la morfología y tamaño de las inclusiones cambia al aumentar la temperatura de sinterización y el tiempo, lo que puede suponer el punto de partida para investigaciones futuras.Ingeniería Industria

Mechanical properties of advanced high-strength steels produced via quenching and partitioning

Mención Internacional en el título de doctorAdvanced high-strength steel (AHSS) grades have been frequently used for applications that require a compromise between cost reduction, mechanical behavior and reliability of components that work under static and fatigue service loading conditions. Quenching and Partitioning (Q&P) is receiving increasing attention as a novel heat treatment to produce AHSSs containing martensite/retained austenite mixtures, with desirable combination of strength, ductility and toughness. However, despite the significant body of research on microstructure and mechanical properties of Q&P steels, there is still a significant lack of knowledge on the effect of microstructural architecture on their mechanical performance. Particularly, no research on fatigue and fracture behavior of Q&P steels has been carried out up-todate. Therefore, the main objective of this PhD thesis is to develop a concept of microstructural design in Q&P steels in order to improve a wide range of mechanical properties (uniaxial tensile, fatigue and fracture), as well as to gain fundamental understanding of their relationship with the microstructure and Q&P processing parameters. It is demonstrated that: (i) tensile mechanical behavior and strain partitioning between phases strongly depend on the microstructure of Q&P steels, which, in turn, can be tuned via manipulation of the Q&P parameters; (ii) matrix conditions play an important role in fracture behavior of Q&P steels and (iii) fatigue life of Q&P steels is also determined by their microstructure and can be enhanced via improvement of strength of interphase boundaries. Based on the analysis of the experimental results, it is shown that tailoring of the microstructure of Q&P processed steels can lead to further improvement of their mechanical performance.Los Aceros Avanzados de Alta Resistencia (AHSSs) se utilizan generalmente en la fabricación de componentes que trabajan en condiciones de servicio estáticas y/o a fatiga. Por lo tanto, es necesario que proporcionen un buen compromiso entre coste, comportamiento mecánico y fiabilidad. En los últimos años, se está prestando una gran atención hacia el novedoso tratamiento térmico conocido en inglés como "Quenching and Partitioning" (Q&P) para la producción de AHSSs con microestructuras multifásicas que consisten en mezclas de martensita y austenita retenida, proporcionando de este modo la combinación de resistencia, ductilidad y tenacidad deseada. Sin embargo, a pesar de que ya se ha realizado un importante trabajo de investigación para avanzar en la comprensión de la microestructura y las propiedades mecánicas de estos aceros, resulta imprescindible profundizar aún más en el efecto que la arquitectura microestructural tiene en los aceros Q&P. En particular, no se ha realizado hasta la fecha ningún trabajo que analice el comportamiento a fatiga y fractura de los aceros Q&P. Por este motivo, el principal objetivo de la presente Tesis Doctoral es desarrollar el concepto de diseño microestructural en los aceros Q&P. De este modo se busca mejorar un amplio rango de propiedades mecánicas entre las que se incluyen la resistencia a tracción, así como a fatiga y fractura. Asimismo, se busca establecer la relación entre las citadas propiedades mecánicas, la microestructura y los parámetros de procesado. En este trabajo se ha comprobado que: (i) el comportamiento a tracción y la partición de la deformación entre distintas fases depende en gran medida de la microestructura de los aceros Q&P que, por otra parte, puede ajustarse gracias a la manipulación de los parámetros de procesado Q&P; (ii) las propiedades de la matriz juegan un papel muy importante en el comportamiento a fractura de los aceros Q&P y (iii) la vida a fatiga de los aceros Q&P también está determinada por la microestructura y puede ser mejorada reforzando los bordes entre fases. En base al análisis de los resultados experimentales obtenidos, se muestra que el rendimiento mecánico de los aceros Q&P puede mejorarse a través del diseño microestructural.Programa Oficial de Doctorado en Ciencia e Ingeniería de MaterialesPresidente: José Manuel Torralba Castelló.- Secretario: José María Cabrera Marrero.- Vocal: Laura Molí Sánche

Cement-based mortar patch repair of RC columns. Comparison with all-four-sides and one-side repair

[EN] This paper describes an experimental study on patch-repaired reinforced concrete columns subjected to axial loads until failure. The behaviour of four series of columns repaired with Class R3 and R4 cement-based mortar was analysed both with and without a bonding agent. The results obtained were compared with control series of undamaged and damaged but unrepaired columns to determine the effectiveness of the repairs and the subsequent improvement in the behaviour of the columns. The results of this study were compared with those of previous work by the authors on the analysis of all-four-side repairs and one-side repairs. The conclusion reached was that patch repairs are highly effective as compared to the other techniques studied and that using Class R3 mortar achieves better results on damaged columns made with low-quality concrete. It was also concluded that applying a bonding agent does not improve the results, although this element was found to be necessary to prevent the premature detachment of the repair when there is a substantial difference between the stiffness of the column concrete and that of the mortar used in the repairs. (C) 2018 Elsevier Ltd. All rights reserved.The authors wish to express their gratitude to the HADES CONSTRUCCIONES Y CREACIONES 2003 company for their human and material contributions to this work.Ortega, I.; Pellicer, TM.; Calderón García, PA.; Adam, JM. (2018). Cement-based mortar patch repair of RC columns. Comparison with all-four-sides and one-side repair. Construction and Building Materials. 186:338-350. https://doi.org/10.1016/j.conbuildmat.2018.07.148S33835018

Axially loaded RC columns repaired on one side with cement-based mortars

[EN] This paper describes and analyses the results of an experimental programme carried out at the Universitat Politecnica de Valencia on 18 reinforced concrete (RC) columns, 12 of which had been repaired on one side with cement-based mortar before being subjected to axial loading until failure. The objective of the research was to determine the performance of the columns that had been repaired using different mortars, evaluate the influence of Class R3 and R4 mortar used and of the application of a binder or bonding agent. The results obtained were compared with those of the undamaged control columns and those of the unrepaired damaged columns to obtain values for the efficiency of the repairs and for the improvement in the load-bearing capacity of the columns. The results obtained indicate that the columns repaired with Class R3 mortar, with a lower elasticity modulus, function in better way than the Class R4 repaired ones. The presence or absence of a binder was not found to be a determining factor in improving the behaviour of the repaired elements. The chief novelty of the study lies in the fact that it is the first experimental study on RC columns totally repaired on one side only, using different types of mortar with and without the application of a binder. (C) 2018 Elsevier Ltd. All rights reserved.The authors express their gratitude to HADES CONSTRUCCIONES Y CREACIONES 2003 for their material, human and financial support.Ortega, I.; Pellicer, TM.; Calderón García, PA.; Adam, JM. (2018). Axially loaded RC columns repaired on one side with cement-based mortars. Construction and Building Materials. 177:1-9. https://doi.org/10.1016/j.conbuildmat.2018.05.102S1917