Implementing energy saving algorithms for Ethernet link aggregates with ONOS

During the last few years, there has been plenty of research for reducing energy consumption in telecommunication infrastructure. However, many of the proposals remain unim-plemented due to the lack of flexibility in legacy networks. In this paper we demonstrate how the software defined networking (SDN) capabilities of current networking equipment can be used to implement some of these energy saving algorithms. In particular, we developed an ONOS application to realize an energy-aware traffic scheduler to a bundle link made up of Energy Efficient Ethernet (EEE) links between two SDN switches. We show how our application is able to dynamically adapt to the traffic characteristics and save energy by concentrating the traffic on as few ports as possible. This way, unused ports remain in Low Power Idle (LPI) state most of the time, saving energy.Comment: 8 pages, 10 figure

DERECHO Y POLÍTICAS AMBIENTALES EN ASTURIAS

DERECHO Y POLÍTICAS AMBIENTALES EN ASTURIA

Portable low profile antenna at X-band

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 and ITU-R S.465-5 for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band with a VSWR of 1.4:1. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarization

Derecho y políticas ambientales en Asturias

Derecho y políticas ambientales en Asturia

Jurisprudencia ambiental en Asturias

Jurisprudencia ambiental en Asturia

Estrategia simulación de situaciones cotidianas con GeoGebra para el aprendizaje de geometría bidimensional, estudiantes del segundo grado del nivel secundario

Utilizar un software matemático permite, a través de la simulación, comprender e interpretar la información proveniente del entorno del estudiante. En ese marco, el objetivo del estudio fue diseñar la estrategia simulación de situaciones cotidianas con el software GeoGebra para el aprendizaje de geometría bidimensional. La investigación es de tipo aplicada, de nivel descriptivo y modalidad propositiva. El contexto de estudio corresponde a una institución educativa rural de la provincia de Chota, región Cajamarca, donde se contó con la participación de 20 estudiantes de segundo grado de secundaria. Al describir la unidad de análisis se aplicó un cuestionario, a través del cual se recogió la información sobre el aprendizaje de la geometría bidimensional en base a tres dimensiones: adquiere e integra, profundiza y aplica. Como resultado se obtuvo que la mayoría de estudiantes se encuentra en el nivel de logro en inicio en cada una de las dimensiones propuestas. Posteriormente, se aplicó la correlación Rho de Spearman, demostrándose que dicha correlación fue positiva alta entre cada una de las dimensiones y el aprendizaje de geometría bidimensional, lo que significa que al incrementar actividades con la estrategia simulación de situaciones cotidianas con GeoGebra permitirá mejorar el aprendizaje de geometría bidimensional en los estudiantes del segundo grado de secundaria de la Institución Educativa Sagrado Corazón de Jesús, La Ramada, Chota

DERECHO Y POLÍTICAS AMBIENTALES EN ASTURIAS

DERECHO Y POLÍTICAS AMBIENTALES EN ASTURIA

Efficiency of the solution representations for the hybrid flow shop scheduling problem with makespan objective

In this paper we address the classical hybrid flow shop scheduling problem with makespan objective. As this problem is known to be NP-hard and a very common layout in real-life manufacturing scenarios, many studies have been proposed in the literature to solve it. These contributions use different solution representations of the feasible schedules, each one with its own advantages and disadvantages. Some of them do not guarantee that all feasible semiactive schedules are represented in the space of solutions –thus limiting in principle their effectiveness– but, on the other hand, these simpler solution representations possess clear advantages in terms of having consistent neighbourhoods with well-defined neighbourhood moves. Therefore, there is a trade-off between the solution space reduction and the ability to conduct an efficient search in this reduced solution space. This trade-off is determined by two aspects, i.e. the extent of the solution space reduction, and the quality of the schedules left aside by this solution space reduction. In this paper, we analyse the efficiency of the different solution representations employed in the literature for the problem. More specifically, we first establish the size of the space of semiactive schedules achieved by the different solution representations and, secondly, we address the issue of the quality of the schedules that can be achieved by these representations using the optimal solutions given by several MILP models and complete enumeration. The results obtained may contribute to design more efficient algorithms for the hybrid flow shop scheduling problem.Ministerio de Ciencia e Innovación DPI2016-80750-