Study and experimental verification of control tuning strategies in a variable speed wind energy conversion system

This paper analyzes and compares different control tuning strategies for a variable speed wind energy conversion system (WECS) based on a permanent-magnet synchronous generator (PMSG). The aerodynamics of the wind turbine (WT) and a PMSG have been modeled. The control strategy used in this research is composed of three regulators, which may be based on either linear or nonlinear controllers. In this analysis, proportional-integral (PI) linear controllers have been used. Two different tuning strategies are analyzed and compared. The main goal is to enhance the overall performance by achieving a low sensitivity to disturbances and minimal overshoot under variable operating conditions. Finally, the results have been verified by an experimental WECS laboratory prototype.     

Simple and efficient inductive telemetry system with data and power transmission

This paper presents an inductive telemetry system useful for isolated applications that have to be powered and/or controlled from outside. The transmitter is based on a Class-E amplifier with ASK modulation generated with a resonant modulation to obtain the different levels to transmit. In the receiver two possible configurations, parallel and serial, are studied and the serial configuration is proposed to reduce the effect of the rectifier and the filter over the received signal. Also an ASK demodulator is fabricated in an ASIC. All the system (transmitter-receiver) has been tested and a 60% of efficiency in power transmission is obtained at a distance of 10 mm. For the data link a bit rate 1 Mbps with a carrier of 8 MHz at a distance of 20 mm has been obtained.     

A Fair and Secure Cluster Formation Process for Ad Hoc Networks

An efficient approach for organizing large ad hoc networks is to divide the nodes into multiple clusters and designate, for each cluster, a clusterhead which is responsible for holding intercluster control information. The role of a clusterhead entails rights and duties. On the one hand, it has a dominant position in front of the others because it manages the connectivity and has access to other node’s sensitive information. But on the other hand, the clusterhead role also has some associated costs. Hence, in order to prevent malicious nodes from taking control of the group in a fraudulent way and avoid selfish attacks from suitable nodes, the clusterhead needs to be elected in a secure way. In this paper we present a novel solution that guarantees the clusterhead is elected in a cheat-proof manner.     

Essentiality of managing the resource information in the coordinated fog‐to‐cloud paradigm

Fog‐to‐cloud (F2C) computing is an emerging computational platform. By combing the cloud, fog, and IoT, it provides an excellent framework for managing and coordinating the resources in any smart computing domain. Efficient management of these kinds of diverse resources is one of the critical tasks in the F2C system. Also, it must be considered that different types of services are offered by any smart system. So, before managing these resources and enabling the various types of services, it is essential to have some comprehensive informational catalogue of resources and services. Hence, after identifying the resource and service‐task taxonomy, our main aim in this paper is finding out a solution for properly organizing this information over the F2C system. For that purpose, we are proposing a modified F2C framework where all the information is distributively stored near to the edge of the network. Finally, by presenting some experimental results, we evaluate and validate the performance of our proposing framework.     

End-user traffic policing for QoS assurance in polyservice RINA networks

Telecommunication Systems - Looking at the ever-increasing amount of heterogeneous distributed applications supported on current data transport networks, it seems evident that best-effort packet...     

Enhanced domain disjoint backward recursive TE path computation for PCE-based multi-domain networks

The ability of computing optimal routes poses new challenges when extending it to larger multi-domain network scenarios, as the quality of these computed end-to-end inter-domain routes depends on the selection of the domain sequence to be traversed. In the scope of the Internet Engineering Task Force (IETF), the Path Computation Element (PCE) Working Group has not provided definitive solutions to address the domain sequence selection problem, being still a work in progress. To this goal, the Path Computation Flooding (PCF) approach appears as a possible extension to Backward Recursive PCE-based Computation (BRPC) to calculate optimal end-to-end inter-domain paths without requiring a pre-configured domain sequence. Nonetheless, PCF presents major scalability issues in terms of network control overhead and path computation complexity, thus pleading for more accurate domain sequence selection techniques. This paper describes two novel mechanisms to establish inter-domain paths calculating the sequence of domains to be crossed when it is not known in advance. Both procedures make a good trade-off between the control overhead introduced and the accuracy of the computed end-to-end route. The obtained simulation results show the benefits of the proposed contributions, drastically reducing the control overhead while keeping the connection blocking probability close to the optimal values.     

Dual Costimulatory and Coinhibitory Targeting with a Hybrid Fusion Protein as an Immunomodulatory Therapy in Lupus Nephritis Mice Models

Systemic lupus erythematosus is a complex autoimmune disorder mostly mediated by B-cells in which costimulatory signals are involved. This immune dysregulation can cause tissue damage and inflammation of the kidney, resulting in lupus nephritis and chronic renal failure. Given the previous experience reported with CTLA4-Ig as well as recent understanding of the PD-1 pathway in this setting, our group was encouraged to evaluate, in the NZBWF1 model, a human fusion recombinant protein (Hybri) with two domains: CTLA4, blocking the CD28—CD80 costimulatory pathway, and PD-L2, exacerbating the PD-1–PD-L2 coinhibitory pathway. After achieving good results in this model, we decided to validate the therapeutic effect of Hybri in the more severe MRL/lpr model of lupus nephritis. The intraperitoneal administration of Hybri prevented the progression of proteinuria and anti-dsDNA antibodies to levels like those of cyclophosphamide and reduced the histological score, infiltration of B-cells, T-cells, and macrophages and immune deposition in both lupus-prone models. Additionally, Hybri treatment produced changes in both inflammatory-related circulating cytokines and kidney gene expression. To summarize, both in vivo studies revealed that the Hybri effect on costimulatory-coinhibitory pathways may effectively mitigate lupus nephritis, with potential for use as a maintenance therapy.     

Atmospheric occurrence and deposition of polycyclic aromatic hydrocarbons in the northeast tropical and subtropical Atlantic Ocean

Atmospheric transport and deposition of polycyclic aromatic hydrocarbons (PAHs) over tropical oceans has not yet been studied even though tropical oceans account for 35% of the global oceans. Here we show the results from measurements of gas- and aerosol-phase PAHs and dry deposition samples in the NE tropical Atlantic Ocean atmosphere, a region between 26 degrees and 21 degrees N, off shore of the Saharan desert. The results show that PAHs concentrations are high at the coastal ocean (15-20 ng m(-3) for sum of 27 gas-phase individual PAHs) and decrease by a factor of 2-3 at open ocean (26 degrees W). The spatial variability observed is consistent with dilution, reaction, and deposition during transport. Atmospheric dry deposition velocities ranged between 0.1 and 0.3 cm s(-1) with higher deposition velocities for the more volatile PAHs. Outbreaks of Saharan Dust significantly increase the deposition rates of PAHs. The occurrence and deposition of PAHs in tropical regions is complex and results from the interplay of a number of processes, such as wind speed, aerosol loads, important sources from West Africa, processes controlling the diurnal variability, and sequestration driven by high primary productivity regions. The measured average atmospheric residence times of gas- and aerosol-phase PAHs are 3.7 and 3.5 days, respectively.     

Solid-phase receptor-based assay for the detection of cyclic imines by chemiluminescence, fluorescence, or colorimetry

The spirolides and gymnodimines are marine phycotoxins included in the group of cyclic imines. The toxicity of these compounds to humans is still unknown, although their toxicity by intraperitoneal injection in rodents is very high. A receptor-based method was developed using the competition of the 13-desmethyl spirolide C with biotin-labeled α-bungarotoxin for binding to nicotinic acetylcholine receptors and the immobilization of the α-bungarotoxin-receptor complex on streptavidin-coated surfaces. The quantification of the immobilized receptor can be achieved using a specific antibody. Finally, after the addition of a secondary antibody labeled with horseradish peroxidase, three alternative substrates of this enzyme generate a chemiluminescent, fluorescent, or colorimetric signal. The assay performs well in shellfish extracts and the detection range is 5-150 nM of 13-desmethyl spirolide C in shellfish extracts, which is at least 5 times more sensitive than the existing fluorescence polarization assay. This assay can also detect gymnodimine, although with 10 times lower sensitivity than the spirolide. The detection of cyclic imines with microplate assays would be useful for screening purposes in order to reduce the number of samples to be processed by bioassays or analytical methods.     

Use of gold island films in design of reflectors with high luminosity

We describe the optical properties of gold island films embedded between SiO2 and/or TiO2 layers. Plasmonic properties of gold films have been characterized using spectrometry and variable angle spectroscopic ellipsometry for various combinations of the embedding media. The obtained refractive indices of embedded gold island films have been used in the design of several types of multilayer reflectors.