From Perception to Navigation in Environments with Persons: An Indoor Evaluation of the State of the Art

Research in the field of social robotics is allowing service robots to operate in environments with people. In the aim of realizing the vision of humans and robots coexisting in the same environment, several solutions have been proposed to (1) perceive persons and objects in the immediate environment; (2) predict the movements of humans; as well as (3) plan the navigation in agreement with socially accepted rules. In this work, we discuss the different aspects related to social navigation in the context of our experience in an indoor environment. We describe state-of-the-art approaches and experiment with existing methods to analyze their performance in practice. From this study, we gather first-hand insights into the limitations of current solutions and identify possible research directions to address the open challenges. In particular, this paper focuses on topics related to perception at the hardware and application levels, including 2D and 3D sensors, geometric and mainly semantic mapping, the prediction of people trajectories (physics-, pattern- and planning-based), and social navigation (reactive and predictive) in indoor environments

Cu(In,Ga)Se2 absorber thinning and the homo-interface model: Influence of Mo back contact and 3-stage process on device characteristics

Thinning the absorber layer is one of the possibilities envisaged to further decrease the production costs of Cu(In,Ga)Se2 (CIGSe) thin films solar cell technology. In the present study, the electronic transport in submicron CIGSe-based devices has been investigated and compared to that of standard devices. It is observed that when the absorber is around 0.5 μm-thick, tunnelling enhanced interface recombination dominates, which harms cells energy conversion efficiency. It is also shown that by varying either the properties of the Mo back contact or the characteristics of 3-stage growth processing, one can shift the dominating recombination mechanism from interface to space charge region and thereby improve the cells efficiency. Discussions on these experimental facts led to the conclusions that 3-stage process implies the formation of a CIGSe/CIGSe homo-interface, whose location as well as properties rule the device operation; its influence is enhanced in submicron CIGSe based solar cells

Estudio paleontológico en las cuencas terciarias de Galicia

Se ha realizado una prospección paleontológica en nueve cuencas terciarias gnllegas, con el fin dc prccisar su edad y condiciones pnleoombiclltales. Presentamos los resultados obtenidos en base a hallazgos de micromamíferos, grandes mamíferos, peces, macrorestos vegetales y moluscos en las cuencas de As Pontes (A Coruila) y Roupar (Lugo). Las arci llas de los niveles inferiores de As Pontes contienen roedores, cuya edad corresponde al principio del Oligoceno superior (MP 25-26). Los lignitos inferiores han proporcionado un Antracotérido que probablemente corresponde también al Oligoceno. Las plantas de los niveles superiores pueden ser del Oligoceno o del Mioceno inferior. Las condiciones climáticas, siempre tropicales, debieron variar de cálidas a húmedas. En las arcillas inferiores hay peces y moluscos tanto dulceacuícolas como eurihalinos, y moluscos marinos litorales. Se apoyan con estos datos las hipótesis de contemporaneidad entre las cuencas de As Pontes y Roupar, y su carácter parálic

IRIS: Efficient Visualization, Data Analysis and Experiment Management for Wireless Sensor Networks

The design of ubiquitous computing environments is challenging, mainly due to the unforeseeable impact of real-world environments on the system performance. A crucial step to validate the behavior of these systems is to perform in-field experiments under various conditions. We introduce IRIS, an experiment management and data processing tool allowing the definition of arbitrary complex data analysis applications. While focusing on Wireless Sensor Networks, IRIS supports the seamless integration of heterogeneous data gathering technologies. The resulting flexibility and extensibility enable the definition of various services, from experiment management and performance evaluation to user-specific applications and visualization. IRIS demonstrated its effectiveness in three real-life use cases, offering a valuable support for in-field experimentation and development of customized applications for interfacing the end user with the system

Van Der Waals Heteroepitaxy of GaSe and InSe, Quantum Wells and Superlattices

Bandgap engineering and quantum confinement in semiconductor heterostructures provide the means to fine-tune material response to electromagnetic fields and light in a wide range of the spectrum. Nonetheless, forming semiconductor heterostructures on lattice-mismatched substrates has been a challenge for several decades, leading to restrictions for device integration and the lack of efficient devices in important wavelength bands. Here, we show that the van der Waals epitaxy of two-dimensional (2D) GaSe and InSe heterostructures occur on substrates with substantially different lattice parameters, namely silicon and sapphire. The GaSe/InSe heterostructures were applied in the growth of quantum wells and superlattices presenting photoluminescence and absorption related to interband transitions. Moreover, we demonstrate a self-powered photodetector based on this heterostructure on Si that works in the visible-NIR wavelength range. Fabricated at wafer-scale, these results pave the way for an easy integration of optoelectronics based on these layered 2D materials in current Si technology.Comment: 16 Pages, 5 figures. Supplementary Information included in the end (+10 pages, +10 Figures, + 2 Tables). Partially presented at 21st ICMBE - September 202

Photoreflectance analysis of a GaInP/GaInAs/Ge multijunction solar cell

We have analyzed the photoreflectance spectra of a GaInP/GaInAs/Ge triple junction solar cell. The spectra reveal signatures from the window layer and middle and top subcells included in the stack. Additional contributions from the multilayer buffer introduced between the mismatched bottom and middle cells have been detected. Franz–Keldysh oscillations (FKOs) dominate the spectra above the fundamental bandgaps of the GaInP and GaInAs absorbers. From the FKO analysis, we have estimated the dominant electric fields within each subcell. In light of these results, photoreflectance is proposed as a useful diagnostic tool for quality assessment of multijunction structures prior to completion of the device or at earlier stages during its processing

Development of a Fixed-Wing Drone System for Aerial Insect Sampling

Most current insect research techniques are ground-based and provide scarce information about flying insects in the planetary boundary layer (PBL), which remains a poorly studied ecological niche. To address this gap, we developed a new insect-sampling method consisting of a fixed-wing drone platform with net traps attached to the fuselage, a mobile design that has optimal aerodynamic characteristics for insect capture in the PBL. We tested the proposed device on 16 flights in Doñana National Park (Spain) with two different trap designs fitted on the fuselage nose and wing. We collected 34 insect specimens belonging to four orders with a representation of twelve families at mean altitudes below 23 m above ground level and sampling altitudes between 9 and 365 m. This drone insect-sampling design constitutes a low-cost and low-impact method for insect monitoring in the PBL, especially in combination with other remote sensing technologies that directly quantify aerial insect abundance but do not provide taxonomic information, opening interesting possibilities for ecology and entomological research, with the possibility of transfer to economically important sectors, such as agriculture and health

La estructura sísmica de la corteza de la Zona de Ossa Morena y su interpretación geológica

El experimento de sísmica de reflexión profunda IBERSEIS ha proporcionado una imagen de la corteza del Orógeno Varisco en el sudoeste de Iberia. Este artículo se centra en la descripción de la corteza de la Zona de Ossa Morena (OMZ), que está claramente dividida en una corteza superior, con reflectividad de buzamiento al NE, y una corteza inferior de pobre reflectividad. Las estructuras geológicas cartografiadas en superficie se correlacionan bien con la reflectividad de la corteza superior, y en la imagen sísmica se ven enraizar en la corteza media. Ésta está constituida por un cuerpo muy reflectivo, interpretado como una gran intrusión de rocas básicas. La imagen de las suturas que limitan la OMZ muestra el carácter fuertemente transpresivo de la colisión orogénica varisca registrada en el sudoeste de Iberia. La Moho actual es plana y, en consecuencia, no se observa la raíz del orógeno