Neural Controller for a Mobile Robot in a Nonstationary Enviornment

Recently it has been introduced a neural controller for a mobile robot that learns both forward and inverse odometry of a differential-drive robot through an unsupervised learning-by-doing cycle. This article introduces an obstacle avoidance module that is integrated into the neural controller. This module makes use of sensory information to determine at each instant a desired angle and distance that causes the robot to navigate around obstacles on the way to a final target. Obstacle avoidance is performed in a reactive manner by representing the objects and target in the robot's environment as Gaussian functions. However, the influence of the Gaussians is modulated dynamically on the basis of the robot's behavior in a way that avoids problems with local minima. The proposed module enables the robot to operate successfully with different obstacle configurations, such as corridors, mazes, doors and even concave obstacles.Air Force Office of Scientific Research (F49620-92-J-0499

Space station integrated wall design and penetration damage control

A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment

Space station integrated wall design and penetration damage control

The analysis code BUMPER executes a numerical solution to the problem of calculating the probability of no penetration (PNP) of a spacecraft subject to man-made orbital debris or meteoroid impact. The codes were developed on a DEC VAX 11/780 computer that uses the Virtual Memory System (VMS) operating system, which is written in FORTRAN 77 with no VAX extensions. To help illustrate the steps involved, a single sample analysis is performed. The example used is the space station reference configuration. The finite element model (FEM) of this configuration is relatively complex but demonstrates many BUMPER features. The computer tools and guidelines are described for constructing a FEM for the space station under consideration. The methods used to analyze the sensitivity of PNP to variations in design, are described. Ways are suggested for developing contour plots of the sensitivity study data. Additional BUMPER analysis examples are provided, including FEMs, command inputs, and data outputs. The mathematical theory used as the basis for the code is described, and illustrates the data flow within the analysis

Input-image homogenization as a method to improve a correlator's discrimination capability

We propose an input-image preprocessing method consisting of homogenization of the image to improve the discrimination capability of a correlation-based recognition process. This method is an approximation of the optimal filter. It offers the advantage that correlation with the preprocessed images can easily be implemented in an optical correlator working with phase-only spatial light modulators

The Birth Plan Experience—A Pilot Qualitative Study in Southern Spain

Background: Healthcare systems advocate for quality care and humanized relations in routine birth care, and have therefore created the Birth Plan, a document available to pregnant women to state their preferences in relation to the birth process. Methods: This qualitative research with a phenomenological design was carried out to record the experiences of women who presented a Birth Plan. Sample selection was carried out using non-probabilistic, intentional and convenience sampling, selecting seven participants who were willing to participate and share their experiences. Results: After analyzing the content of the interviews, four categories emerged: “respecting the woman’s wishes: humanizing the birth process”, “information and primary Care”, “expectations regarding the care received” and “results of using the birth plan”, with their corresponding subcategories. Conclusion: Women consider it beneficial to present a Birth Plan, because it informs them about the process and gives them the opportunity to have a better experience, which takes into account their preferences for making the delivery less instrumental. In addition, they state the importance of having trained professionals involved, and call for more attention to be paid to the birth process in general

Goalkeeper-field player in situations of offensive numerical inferiority in handball: Penalty or advantage?

El objetivo principal fue analizar el resultado final de la acción ofensiva entre los equipos que utilizan, o no, el portero-jugador en situaciones de inferioridad numérica ofensiva en balonmano. Los objetivos secundarios se centran en analizar cómo es la utilización y el comportamiento del portero-jugador y su relación con el resultado final ofensivo y la posterior acción con respecto al contraataque del equipo contrario. Se analizaron las actas oficiales de 86 partidos del 22º Campeonato del Mundo de Balonmano Femenino (Dinamarca 2015) y se realizó el visionado, análisis y registro de las 927 situaciones de inferioridad numérica ofensiva, así como el estudio estadístico pertinente con SPSS v.24. Los resultados demuestran que el uso del recurso táctico o estratégico del portero-jugador favorece la obtención de gol en situaciones de inferioridad numérica ofensiva y no penaliza al equipo que lo utiliza, al no existir diferencia significativa en la probabilidad de recibir gol en contraataqueThe main goal was to analyze the end results in offensive actions between teams that do or do not employ the goalkeeper-field player in situations of offensive numerical inferiority in handball. The secondary objectives focus on analyzing the use and behavior of the goalkeeper-field player, as well as its role in the final offensive result and following actions in terms of the opposing team’s counterattack. 86 official match reports from the 22nd Women's Handball World Championship (Denmark 2015) were analyzed, and the viewing, analysis and registration of the 927 situations of offensive numerical inferiority were carried out, as well as the pertinent statistical study with SPSS v.24. The results show that the tactical or strategic use of the goalkeeper-field player favors goal scoring in situations of offensive numerical inferiority and does not punish the team which employs it, since there’s no significant difference in the probability of conceding a goal in counterattac

Scanning tunneling spectroscopy of layers of superconducting 2H-TaSe2_\textbf{2}: Evidence for a zero bias anomaly in single layers

We report a characterization of surfaces of the dichalcogenide TaSe$_2$ using scanning tunneling microscopy and spectroscopy (STM/S) at 150 mK. When the top layer has the 2H structure and the layer immediately below the 1T structure, we find a singular spatial dependence of the tunneling conductance below 1 K, changing from a zero bias peak on top of Se atoms to a gap in between Se atoms. The zero bias peak is additionally modulated by the commensurate $3a_0 \times 3a_0$ charge density wave of 2H-TaSe$_2$. Multilayers of 2H-TaSe$_2$ show a spatially homogeneous superconducting gap with a critical temperature also of 1 K. We discuss possible origins for the peculiar tunneling conductance in single layers.Comment: 10 pages, 10 figure

Weak ferromagnetism with very large canting in a chiral lattice: (pyrimidine)2FeCl2

The transition metal coordination compound (pyrimidine)2FeCl2 crystallizes in a chiral lattice, space group I 4_1 2 2 (or I4_3 2 2). Combined magnetization, Mossbauer spectroscopy and powder neutron diffraction studies reveal that it is a canted antiferromagnet below T_N = 6.4 K with an unusually large canting of the magnetic moments of 14 deg. from their general antiferromagnetic alignment, one of the largest reported to date. This results in weak ferromagnetism with a ferromagnetic component of 1 mu_B. The large canting is due to the interplay between the antiferromagnetic exchange interaction and the local single-ion anisotropy in the chiral lattice. The magnetically ordered structure of (pyrimidine)2FeCl2, however, is not chiral. The implications of these findings for the search of molecule based materials exhibiting chiral magnetic ordering is discussed.Comment: 6 pages, 5 figure

Hydrotreating of Guaiacol and Acetic Acid Blends over Ni2P/ZSM-5 Catalysts: Elucidating Molecular Interactions during Bio-Oil Upgrading

[EN] Catalytic hydrodeoxygenation (HDO) is an effective technology for upgrading pyrolysis bio-oils. Although, in the past years, this process has been extensively studied, the relevance of the cross-reactivity between the numerous chemical components of bio-oil has been scarcely explored. However, molecular coupling can be beneficial for improving the bio-oil characteristics. With the aim of gaining a better understanding of these interactions, this work investigates the catalytic hydrodeoxygenation of mixtures of two typical components of pyrolysis bio-oils: guaiacol and acetic acid. The catalytic tests were carried out employing a bifunctional catalyst based on nickel phosphide (Ni2P) deposited over a commercial nanocrystalline ZSM-5 zeolite. The influence of both hydrogen availability and temperature on the activity and product distribution, was evaluated by carrying out reactions under different H2 pressures (40¿10 bar) and temperatures (between 260 and 300 °C). Using blends of both substrates, a partial inhibition of guaiacol HDO occurred because of the competence of acetic acid for the catalytic active sites. Nevertheless, positive interactions were also observed, mainly esterification and acylation reactions, which could enhance the bio-oil stability by reducing acidity, lowering the oxygen content, and increasing the chain length of the components. In this respect, formation of acetophenones, which can be further hydrogenated to yield ethyl phenols, is of particular interest for biorefinery applications. Increasing the temperature results in an increment of conversion but a decrease in the yield of fully deoxygenated molecules due to the production of higher proportion of catechol and related products. Additional experiments performed in the absence of hydrogen revealed that esterification reactions are homogeneously self-catalyzed by acetic acid, while acylation processes are mainly catalyzed by the acidic sites of the zeolitic support.The authors thank to the Spanish “Ministry of Economy and Competiveness” for their financial support through the project CATPLASBIO (CTQ2014-60209-R), as well as to the “Regional Government of Madrid” and European Structural Funds for the RESTOENE2 (S2013/MAE-2882) project