Active Disturbance Rejection Control based on Generalized Proportional Integral Observer to Control a Bipedal Robot with Five Degrees of Freedom

An Active Disturbance Rejection Control based on Generalized Proportional Integral observer (ADRC with GPI observer) was developed to control the gait of a bipedal robot with five degrees of freedom. The bipedal robot used is a passive point feet which produces an underactuated dynamic walking. A virtual holonomic constraint is imposed to generate online smooth trajectories which were used as references of the control system. The proposed control strategy is tested through numerical simulation on a task of forward walking with the robot exposed to external disturbances. The performance of ADRC with GPI observer strategy is compared with a feedback linearization with proportional-derivative control. A stability test consisting on analyzing the existence of limit cycles using the Poincaré's method revealed that asymptotically stable walking was achieved. The proposed control strategy effectively rejects the external disturbances and keeps the robot in a stable dynamic walking

Robust compound control of dynamic bipedal robots

This paper presents a robust compound control strategy to produce a stable gait in dynamic bipedal robots under random perturbations. The proposed control strategy consists of two interactive loops: an adaptive trajectory generator and a robust trajectory tracking controller. The adaptive trajectory generator produces references for the robot controlled joints without a-priori knowledge of the terrain features and minimizes the effects of disturbances and model uncertainties during the gait, particularly during the support-leg exchange. The trajectory tracking controller is a non-switching robust multivariable generalized proportional integral (GPI) controller. The GPI controller rejects external disturbances and uncertainties faced by the robot during the swing walking phase. The proposed control strategy was evaluated on the numerical model of a five-link planar bipedal robot with one degree of under-actuation, four actuators, and point feet. The results showed robust performance and stability under external disturbances and model parameter uncertainties on uneven terrain with uphills and downhills. The stability of the gait was proven through the computation of a Poincaré return map for a hybrid zero dynamics with uncertainties (HZDU) model, which shows convergence to a bounded neighborhood of a nominal orbital periodic behavior

A new human embryonic cell type associated with activity of young transposable elements allows definition of the inner cell mass

AU : AbbreviationlistshavebeencompiledforthoseusedinFigs1to4:There remains much that we do not understand about the earPlileesatsesvtaergiefysthoaftahlulemntarniedsaerveecloorpr-ect: ment. On a gross level, there is evidence for apoptosis, but the nature of the affected cell types is unknown. Perhaps most importantly, the inner cell mass (ICM), from which the foetus is derived and hence of interest in reproductive health and regenerative medicine, has proven hard to define. Here, we provide a multi-method analysis of the early human embryo to resolve these issues. Single-cell analysis (on multiple independent datasets), supported by embryo visualisation, uncovers a common previously uncharacterised class of cells lacking commitment markers that segregates after embryonic gene activation (EGA) and shortly after undergo apoptosis. The discovery of this cell type allows us to clearly define their viable ontogenetic sisters, these being the cells of the ICM. While ICM is characterised by the activity of an Old non-transposing endogenous retrovirus (HERVH) that acts to suppress Young transposable elements, the new cell type, by contrast, expresses transpositionally competent Young elements and DNA-damage response genes. As the Young elements are RetroElements and the cells are excluded from the developmental process, we dub these REject cells. With these and ICM being characterised by differential mobile element activities, the human embryo may be a “selection arena” in which one group of cells selectively die, while other less damaged cells persist.European Research Council, ERC Advanced [ERC-2011-ADG 294742European Research Council, ERC Advanced [ERC-2014-ADG 669207]CICE-FEDER-P12-CTS-2256Plan Nacional de I+D+I 2008-20112013-2016 (FIS-FEDER-PI14/02152)PCIN-2014-115-ERANET NEURON IIthe European Research Council (ERC-Consolidator ERC-STG-2012-309433)The Wellcome Trust-University of Edinburgh Institutional Strategic Support Fund (ISFF2)Ms Francisca Serran

Auditoria de calidad al servicio de la biblioteca de una IES

La presente investigación documenta la realización de una auditoría de calidad realizada a la biblioteca de una Institución de Educación Superior. Siendo que es importante conocer el nivel de satisfacción, expectativas de los usuarios a fin de incrementar la calidad en el servicio. El objetivo del estudio es realizar una auditoría de calidad en el servicio a Biblioteca Santiago Velasco Ruiz, de la Facultad de Contaduría y Administración de la Universidad Autónoma del Estado de México. Se empleó como instrumento de medición el LibQual creada por la Asociación de Investigación de los Estado Unidos, para definir el tamaño de la muestra se tomó en cuenta la sugerencia de Bartlett, Kotrlik y Higgins (2001), quienes proponen que para calcular el tamaño de la muestra requerido en una investigación donde se utiliza una encuesta con escala Likert debe hacerse uso de la fórmula de datos continuos de Cochran

Reliability based design of marine risers

PhD ThesisThe harsh environment in which offshore structures must operate, their intended service life and the uncertainties inherent to the load processes, have been the impulse for investigation of their reliability. The method most extensively applied for this purpose during the last two decades was the Structural Systems Reliability, which can not be coupled with the finite element method. Therefore the objectives of the present work are to investigate the applicability of a technique which allows the utilization of the reliability analysis methods with a marine riser modelled by the finite element method, FEM, and revision of the reliability levels associated with this riser, including the fatigue life. For these purposes the response surface methodology was selected, among a number of methods. A response surface approach which requires a low number of experiments with the FEM model was elected, calculations for construction of the response surface are further simplified by the assumption of statistical independence among the basic variables. It is demonstrated in the present study that the response surface is capable of producing an equivalent and explicit limit state function which is used at a second stage with the First Order Reliability Method and the Adaptive Importance Sampling simulation technique. However, it was found that the assumption of independence is not always valid. In this case, a method is proposed in which the correlated variables are implicitly considered at the level of the mechanical model. The reliability of the marine riser was reviewed with the proposed algorithms, finding that the validity of the reliability levels depend on the number of basic variables considered and their statistical properties. The significant reduction in required computing time achieved with the response surface methodology allowed parametric studies to be carried out, in order to investigate the impact of different statistical properties of the basic variables. The fatigue reliability case was also investigated with the S-N approach. The introduction of uncertainty in the fatigue life estimation proved that acceptable levels of deterministic fatigue life may render unacceptablelevels of reliability. The uncertainty associated with the stress range is the most significant variable, though the present fatigue reliability formats consider it in a very simplified manner, therefore an approach is suggested with which the stress uncertainty can be considered in a more detailed fashion. However, the algorithm used here for construction of the response surface was unable to produce the required surface. Therefore it is concluded that though the response surface is capable of handling a large number of structural reliability cases, there are instances in which more research efforts are needed.Consejo Nacional de Ciencia y Tecnologia: CONACYT (National Council for Science and Technology): Mexican Government

Strategic supply in the health sector impacted by covid 19

La aparición del virus -COVID19 ha desarrollado problemas de abastecimiento en el sector salud, tanto para cubrir las necesidades de atención a la población enferma como para la adquisición de los elementos de protección personal o bien mencionados elementos de bioseguridad, disminuyendo en el mercado una oferta oportuna, con elevados costos de adquisición y por ende aumentando costos operacionales, ocasionando muchas veces déficit de oportunidad en la atención al paciente. En búsqueda de una información veraz y respaldada. Se valida en diferentes buscadores documentación referente a este tema de gran impacto, dentro de ellos esta: Clinicalkey, sciencedirect y google académico, los cuales fueron útiles para la información suministrada, en el presente documento, excluyendo literatura no propia al tema expuesto. En busca de apoyar las necesidades de información se ilustra un panorama óptimo de los procesos a tener en cuenta ante circunstancias inusuales, usando las herramientas básicas como la estadística y optimizando su uso. Los temas expuestos son de impacto directo y de construcción para el mejoramiento de las instituciones prestadores de salud, los cuales ayudan al mejor rendimiento de los procesos y protegen elementos financieros, sin dejar a un lado que existen varias maneras de contrarrestar el impacto del COVID-19 en las instituciones de salud, pero estas deben ser llevadas a una validación, exponiendo factores económicos, humanos, estatales, de infraestructura, entre otros.The appearance of the virus -COVID19 has developed supply problems in the health sector, both to meet the needs of care for the sick population and for the acquisition of personal protection elements or the aforementioned elements of biosecurity, decreasing in the market a timely offer, with attention to high acquisition costs and therefore increased operational costs, often causing a deficit of opportunity in the patient. In search of truthful and supported information. Documentation referring to this high-impact topic is validated in different search engines, among them this: Clinicalkey, sciencedirect and academic google, which were useful for the information provided, in this document, excluding literature not specific to the exposed subject. In order to support the information needs, an optimal panorama of the processes to take into account in unusual circumstances is illustrated, using basic tools such as statistics and optimizing their use. The topics presented are of direct impact and construction for the improvement of health-providing institutions, which help the better performance of processes and protect financial elements, without leaving aside that there are several ways to counteract the impact of COVID- 19 in health institutions, but these must be taken to a validation, exposing economic, human, state, infrastructure factors, among others.Especializació

Hybrid disturbance rejection control of dynamic bipedal robots

This paper presents a disturbance rejection control strategy for hybrid dynamic systems exposed to model uncertainties and external disturbances. The focus of this work is the gait control of dynamic bipedal robots. The proposed control strategy integrates continuous and discrete control actions. The continuous control action uses a novel model-based active disturbance rejection control (ADRC) approach to track gait trajectory references. The discrete control action resets the gait trajectory references after the impact produced by the robot’s support-leg exchange to maintain a zero tracking error. A Poincaré return map is used to search asymptotic stable periodic orbits in an extended hybrid zero dynamics (EHZD). The EHZD reflects a lower-dimensional representation of the full hybrid dynamics with uncertainties and disturbances. A physical bipedal robot testbed, referred to as Saurian, is fabricated for validation purposes. Numerical simulation and physical experiments show the robustness of the proposed control strategy against external disturbances and model uncertainties that affect both the swing motion phase and the support-leg exchange

Expression of Homing Receptors in IgM+IgD+CD27+ B Cells and Their Frequencies in Appendectomized and/or Tonsillectomized Individuals

Q4Q3Pacientes apendicectomizados y/o amigdalectomizadosBackground: In humans, blood circulating IgM+IgD+CD27+ B cells are considered analogous to those described in the marginal zone of the spleen and are involved in important immunological processes. The homing receptors they express, and the organs involved in their development (for example, intestinal organs in rabbits) are only partially known. We recently reported that this population is heterogeneous and composed of at least two subsets: one expressing high levels of IgM – IgMhi B cells – and another low levels – IgMlo B cells. Objectives: To evaluate the expression of homing receptors on IgD+CD27+ IgMhi and IgMlo B cells and quantify their frequencies in blood of control and appendectomized and/or tonsillectomized volunteers. Materials and Methods: Using spectral flow cytometry, the simultaneous expression of 12 previously reported markers that differentiate IgMhi B cells and IgMlo B cells and of α4β7, CCR9, CD22 and CCR10 were evaluated in blood circulating B cells of control and appendectomized and/or tonsillectomized volunteers. Results The existence of phenotypically defined IgMlo and IgMhi B cell subsets was confirmed. They differentially expressed intestinal homing receptors, and the expression of α4β7 and CCR9 seems to determine new IgM subpopulations. IgMlo and IgMhi B cells were detected at lower frequencies in the appendectomized and/or tonsillectomized volunteers relative to controls. Conclusions: Human blood circulating IgD+CD27+ IgMlo and IgMhi B cell subsets differentially express homing receptors, and it is necessary to investigate if mucosal organs are important in their development.https://orcid.org/0000-0002-0817-2718https://orcid.org/0000-0002-6973-7639https://orcid.org/0000-0002-0265-0563https://orcid.org/0000-0001-6623-5337Revista Internacional - IndexadaA2N