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5G/6G networks offer high-capacity, low-latency and high-speed communications to new services associated with vertical industries like smart cities, automotive and energy sectors. To achieve this objective, new networking and computing paradigms such as Network Function Virtualization (NFV), Multi-access Edge Computing (MEC) and Software Defined Networking (SDN) are required to bring flexibility and adaptability to networks, while optical networks are envisioned to build the backhaul of 5G/6G networks thanks to their high capacity. Current studies on NFV-5G network planning with MEC resources follow either the online trend or the offline trend. In the online trend, resource allocation to service connection requests is determined upon request arrival based on the available resources. Conversely, in the offline trend, network planning is conducted assuming that the expected traffic (or the full set of service requests) is known in advance. However, to the best of our knowledge, previous works have not assessed the performance of these static offline network plannings when operating under dynamic traffic. In this paper, we evaluate the performance of a previously proposed static planning algorithm for NFV-5G networks under dynamic traffic conditions and analyze the impact of dynamic traffic on the request blocking ratio. Moreover, we also examine the performance of the static planning for each individual service type in a dynamic network scenario with three different available services. The simulation results show that overdimensioning is necessary when planning NFV-5G networks statically, and that the overdimensioning should consider different criteria based on the network expected performance objectives.

se ha observado empíricamente que la violación de los principios de la teoría de la utilidad se produce con frecuencia en la toma de decisiones en entornos de riesgo. Esto llevó a la formulación de la teoría de las perspectivas en la que, además de tener en cuenta la diferente consideración de las pérdidas y las ganancias, así como la postura ante el riesgo de los decisores, mostrando aversión por el riesgo en las ganancias y amor por el riesgo en las pérdidas, se enmarca el efecto certeza. Según el efecto certeza, los decisores tienen tendencia a infravalorar los pagos que son meramente probables, en comparación con aquellos que se obtienen con certeza. Allais mostró la irracionalidad que se produce en la toma de decisiones en este contexto. Por otro lado, para tomar decisiones arriesgadas, es necesario conocer cómo funcionan las probabilidades. Con el objetivo de determinar las relaciones existentes entre la aversión al riesgo, el efecto certeza y el conocimiento básico de la teoría de las probabilidades, se diseñó un estudio experimental en el que se constató, utilizando una formulación basada en la paradoja de Allais, que quienes tienen mayores conocimientos de los principios de la probabilidad muestran una mayor aversión al riesgo, pero el hecho de incurrir en el efecto certeza, sin embargo, es una circunstancia que no se ve afectada significativamente por dicho conocimiento.

Elastic Optical Networks (EONs) are a promising optical technology to deal with the ever-increasing traffic and the vast number of connected devices of the next generation of the Internet, associated to paradigms like the Internet of Things (IoT), the Tactile Internet or the Industry 4.0, to name just a few. In this kind of optical network, each optical circuit or lightpath is provisioned by means of superchannels of variable bandwidth. In this manner, only the necessary bandwidth to accommodate the demand is allocated, improving the spectrum usage. When establishing a connection, the EON control layer determines the modulation format to be used and allocates a portion of the spectrum in a sequence of fibers from the source to the destination node providing the user-demanded bandwidth. This is known as the routing, modulation level and spectrum assignment (RMSA) problem. In this work, we firstly review the most important contributions in that area, and then, we propose a novel RMSA algorithm, multi-path best-fit (MP-BF), which uses a split spectrum multi-path strategy together with a spectrum assignment technique (best-fit), and which jointly exploit the flexibility of EONs. A simulation study has been conducted comparing the performance of EONs when using MP-BF with other proposals from the literature. The results of this study show that, by using MP-BF, the network can increase its performance in terms of lightpath request blocking ratio and supported traffic load, without affecting the energy per bit or the computation time required to find a solution.

Next generation of Internet of Things (IoT) services imposes stringent requirements to the future networks that current ones cannot fulfill. 5G is a technology born to give response to those requirements. However, the deployment of 5G is also accompanied by profound architectural changes in the network, including the introduction of technologies like multi-access edge computing (MEC), software defined networking (SDN), and network function virtualization (NFV). In particular, NFV poses diverse challenges like virtual network function (VNF) placement and chaining, also called VNF-mapping. In this paper, we present an algorithm that solves VNF-placement and chaining in a metro WDM optical network equipped with MEC resources. Therefore, it solves the VNF-mapping in conjunction with the virtual topology design of the underlying optical backhaul network. Moreover, a version of the method providing protection against node failures is also presented. A simulation study is presented to show the importance of designing the three problems jointly, in contrast to other proposals of the literature that do not take the design of the underlying network into consideration when solving that problem. Furthermore, this paper also shows the advantages of using collaboration between MEC nodes to solve the VNF-mapping problem and the advantage of using shared protection schemes. The new algorithm outperforms other proposals in terms of both service blocking ratio, and number of active CPUs (thus reducing energy consumption). Finally, the impact of deploying different physical topologies for the optical backhaul network is also presented.

The assessment of teaching quality in blended learning modalities has become a key element in the context of higher education. However, current evaluation systems present certain limitations. Behavioral scales overcome many of these limitations, offering an alternative for this task. This study describes the process of constructing an assessment instrument with behavioral scales to evaluate university teachers in blended learning modalities, following the BARS (Behavioral Anchored Rating Scales) methodology. The design process included interviews and surveys involving a total of 477 students, as well as a panel of professors who were experts in this teaching modality. The behavioral scales in the final instrument highlight the importance of certain particularly significant teaching-related aspects of blended learning models, namely: teacher-student communication; learning resources; course design; and the teacher’s technical competencies. The authors conclude that the final instrument provides clear and unambiguous feedback, enables the teacher to take specific corrective measures, and reinforces the formative purpose of evaluation in these modalities.

Los cursos online, masivos y abiertos (massive open online courses [MOOC]) representan uno de los máximos exponentes del uso de las nuevas tecnologías en la educación, pues eliminan las barreras físicas y permiten acceder a estudios de altísima calidad de manera gratuita a alumnos procedentes de cualquier rincón del mundo. Con el objetivo de estudiar si, en este sentido, los MOOC pueden llegar a constituir una amenaza para las universidades tradicionales, o si por el contrario pueden convertirse en una herramienta que permita mejorar la docencia universitaria y facilitar el empleo de metodologías docentes activas, creamos cuatro MOOC de áreas de conocimiento afines y los utilizamos como herramienta para el uso de metodologías como la clase invertida (flipped learning) en estudiantes de una misma titulación. Los resultados muestran una mejora muy notable de las calificaciones de los alumnos debido al uso de los MOOC, y, como usuarios habituales de las nuevas tecnologías que son, valoran muy positivamente el uso de herramientas digitales en la encuesta realizada. Sin embargo, cuestionados acerca de la forma ideal de docencia, los alumnos prefirieron casi unánimemente el uso conjunto de los MOOC y de la docencia presencial, mostrando reticencias a la docencia llevada a cabo únicamente de forma online a través de los MOOC.

El objetivo de este trabajo fue evaluar la aceptación de los cursos en línea masivos y abiertos (MOOC, por sus siglas en inglés) en relación con la edad y la generación de los usuarios. La muestra comprendió 103 estudiantes en un programa presencial de aprendizaje de inglés que realizaban MOOC como complemento a su formación. Contestaron una versión en español de una escala basada en el modelo de aceptación de tecnología y adaptada a MOOC. Reportaron una percepción positiva hacia los MOOC y describieron sus beneficios. La edad tuvo una relación débil, positiva y significativa con los factores de aceptación: percepciones de utilidad, facilidad de uso y disfrute. Se presentaron diferencias generacionales, pero sólo las de percepción de utilidad fueron significativas.

Student dropouts at university-level education may result from varied situations and motivations, affecting the courses taught in the distance learning modality,and assuming a cost for both alumni and society. In order to improve learning and reduce the student dropout rate, we used a teaching methodology with distance learning students involving a MOOC as support to university teaching. The MOOC included written materials, explanatory videos, tests in each module, a forum to communicate with peers and teacher, and links to additional materials. Results were very satisfactory, since students had noticeably improved test scores and the number of students who failed the course remarkably reduced. Students also highly appreciated the quality of teaching and significantly improved the results of the previous year. This methodology awas found to apply only when the contents of the MOOC are similar or complementary to those taught in formal education.

Although the literature about MOOCs is abundant, yet many questions remain unresolved regarding their current usefulness and their future evolution. It is necessary to continue with studies that shed light about it. We must to be able to quantify and correctly interpret the collected data. In this issue we have eight papers that will give us a better view of the MOOCs from a practical perspective.