Redundancy in sensors, control and planning of a robotic system for space telerobotics

The analysis and development of a manipulator redundant in structure and sensor devices controlled by a distributed multiprocessor architecture are discussed. The goal has been the realization of a modular structure of the manipulator with evident aspects of flexibility and transportability. The distributed control structure, thanks to his modularity and flexibility could be integrated in the future into an operative structure aimed to space telerobotics. The architecture is applied to the 6 DOF manipulator Gilberto

Graded possibilistic clustering of non-stationary data streams

YesMultidimensional data streams are a major paradigm in data science. This work focuses on possibilistic clustering algorithms as means to perform clustering of multidimensional streaming data. The proposed approach exploits fuzzy outlier analysis to provide good learning and tracking abilities in both concept shift and concept drift

“Un país para volver”: análisis narrativo del Plan de retorno a España

Cada vez más gobiernos lanzan iniciativas explícitamente dirigidas a estimular el retorno de sus emigrantes. En España, el Estado puso en funcionamiento su primera política para el retorno, el “Plan de Retorno a España”, en 2019. Tomando como caso de estudio este plan, el artículo examina la política española para el retorno y la ubica en un contexto más amplio, tanto político como histórico, con objeto de comprender los límites y sesgos de esta medida ante los diversos perfiles de emigrantes españoles. Adoptando el enfoque narrativo de las políticas como perspectiva teórico-analítica y el análisis de contenido como herramienta metodológica, identificamos que, mediante la nueva estrategia narrativa, se ha producido en España un cambio paradigmático en la manera de pensar, desde la esfera pública, el regreso de los ciudadanos españoles asentados en el extranjero. De una mirada asistencial, se ha pasado a adoptar una perspectiva de tipo neoliberal (instrumental y utilitarista), manteniendo, eso sí, una concepción de “la vuelta al país de origen” más próxima a las teorías migratorias predominantes en el siglo XX que a los conceptos científico-sociales contemporáneos. Encontramos, además, una tensión entre las narrativas políticas de España y de la Unión Europea respecto a la movilidad intraeuropea, y un desfase entre la mirada estatal y las realidades migratorias actuales en lo relativo al retorno en contextos de gran incertidumbre económico-laboral

A neural-network-based model predictive control of three-phase inverter with an output LC Filter

Model predictive control (MPC) has become one of the well-established modern control methods for three-phase inverters with an output $LC$ filter, where a high-quality voltage with low total harmonic distortion (THD) is needed. Although it is an intuitive controller, easy to understand and implement, it has the significant disadvantage of requiring a large number of online calculations for solving the optimization problem. On the other hand, the application of model-free approaches such as those based on artificial neural networks approaches is currently growing rapidly in the area of power electronics and drives. This paper presents a new control scheme for a two-level converter based on combining MPC and feed-forward ANN, with the aim of getting lower THD and improving the steady and dynamic performance of the system for different types of loads. First, MPC is used, as an expert, in the training phase to generate data required for training the proposed neural network. Then, once the neural network is fine-tuned, it can be successfully used online for voltage tracking purpose, without the need of using MPC. The proposed ANN-based control strategy is validated through simulation, using MATLAB/Simulink tools, taking into account different loads conditions. Moreover, the performance of the ANN-based controller is evaluated, on several samples of linear and non-linear loads under various operating conditions, and compared to that of MPC, demonstrating the excellent steady-state and dynamic performance of the proposed ANN-based control strategy

Dynamic Collection Scheduling Using Remote Asset Monitoring: Case Study in the UK Charity Sector

Remote sensing technology is now coming onto the market in the waste collection sector. This technology allows waste and recycling receptacles to report their fill levels at regular intervals. This reporting enables collection schedules to be optimized dynamically to meet true servicing needs in a better way and so reduce transport costs and ensure that visits to clients are made in a timely fashion. This paper describes a real-life logistics problem faced by a leading UK charity that services its textile and book donation banks and its high street stores by using a common fleet of vehicles with various carrying capacities. Use of a common fleet gives rise to a vehicle routing problem in which visits to stores are on fixed days of the week with time window constraints and visits to banks (fitted with remote fill-monitoring technology) are made in a timely fashion so that the banks do not become full before collection. A tabu search algorithm was developed to provide vehicle routes for the next day of operation on the basis of the maximization of profit. A longer look-ahead period was not considered because donation rates to banks are highly variable. The algorithm included parameters that specified the minimum fill level (e.g., 50%) required to allow a visit to a bank and a penalty function used to encourage visits to banks that are becoming full. The results showed that the algorithm significantly reduced visits to banks and increased profit by up to 2.4%, with the best performance obtained when the donation rates were more variable

From IR to X-rays: approaches to go through the coating system of historical bowed string musical instruments

Some historical bowed string musical instruments produced in Italy from the 16th to 18th Centuries are considered until now peak-quality masterpieces of the violin-making art. Technical skills were mostly lost after the disappearance of the prominent workshops, and nowadays ancient methods and materials are charming secrets to be revealed by scientific techniques. This work discusses the results obtained by investigating the complex coating systems on bowed string instruments produced by four violin-makers, namely: Jacobus Stainer, Gasparo da Salò, Giovanni Paolo Maggini and Lorenzo Guadagnini. They were selected in order to represent convincingly - albeit not exhaustively - the variety of situations that can be encountered when multi-layered coatings on historical bowed string instruments are considered. The coating systems have been investigated though micro-invasive and non-invasive procedures [1], employing UV-imaging, portable X-ray fluorescence, optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry and Fourier transform infrared microscopy. In addition, two tomographic techniques (synchrotron radiation micro-computed tomography and optical coherence tomography) have been used to image the finishing layers spread on the wood substrate [2,3]. Chemical investigations and images on cross-sections have been compared with the morphological view obtained by tomography, with particular attention to the ability of the tomographic insight to distinguish and measure the various overlying layers, and to highlight the presence of dispersed particles

Nonbacterial Thrombotic Endocarditis in Pancreatic Cancer

Nonbacterial thrombotic endocarditis (NBTE), known as marantic endocarditis, is a phenomenon due to hypercoagulability with a complex pathogenesis. Originally described by Ziegler, the lesions of NBTE were considered to be fibrin thrombi deposited on normal or superficially degenerated cardiac valves [1]. Numerous reports have identified the relationship between NBTE and a variety of different inflammatory states, including chronic diseases like malignancy and autoimmune disease [2, 3]. NBTE is a serious manifestation of prothtombotic state that is characterized by the deposition of thrombi on previously undamaged heart valves in the absence of a bloodstream bacterial infection and by the increased frequency of arterial embolic events in patients with chronic debilitating diseases. Although hypercoagulability is often seen in patients with pancreatic cancer, NBTE has rarely been reported antemortem. We report a case of marantic endocarditis in patient with pancreatic cancer, in which neurological symptoms preceded the diagnosis of pancreatic cancer