This article investigates the cooperative guidance problem for multiple missiles to intercept a maneuvering target. We propose an optimal encirclement guidance, which is known to be suitable for ...improving the observability and limiting the evasive probability of the target. By formulating the optimization problem in a reference frame, the optimal guidance solution can be obtained without any linearization and explicit cooperation can be ensured in regulating the relative line-of-sight angles to achieve encirclement. The main advantage of the proposed approach lies in its nonlinear nature and hence it is more tolerable to disadvantageous initial homing conditions than the linear laws. The working principles and characteristics of the encirclement guidance law are analyzed to support its application. Extensive numerical simulations are performed to validate the proposed approach and demonstrate its advantages.
•Guidance line extraction was proposed based on the morphological characteristics of rice.•Segmented lines and extended virtual lines were created from object edges.•Guidance line was extracted from ...distribution of intersection points.•Error of guidance line was less than 1°.
The guidance line extracted from an image of a rice row precisely guides a robot for weed control in paddy fields. The guidance line enables the robot to follow the crop row without damaging for a successful weed control-equipped vision camera. The accuracy of the guidance line is affected by the morphological characteristics in the image, such as crop leaves, stems, orientation and density. In the case in paddy rice fields, it is difficult to extract the guidance line precisely because leaves are oriented in multiple directions. This paper proposes a new guidance line extraction algorithm to improve the navigation accuracy of weeding robots in paddy fields. The proposed algorithm seeks to identify the central region of the rice plant using the morphological characteristic of which leaves converge normally toward the direction of the central stem region. The guidance line is extracted from the intersection points of virtual straight lines using the modified robust regression. The virtual straight line is represented as the extended line from each segmented straight line created on the edges of the rice plants in the image using the Hough transform. The proposed algorithm was observed to have good performance experimentally with a high accuracy of less than 1° with varying rice plant sizes.
It is now becoming evident that hydrogen peroxide (H2O2), which is constantly produced by nearly all cells, contributes to bona fide physiological processes. However, little is known regarding the ...distribution and functions of H2O2 during embryonic development. To address this question, we used a dedicated genetic sensor and revealed a highly dynamic spatio-temporal pattern of H2O2 levels during zebrafish morphogenesis. The highest H2O2 levels are observed during somitogenesis and organogenesis, and these levels gradually decrease in the mature tissues. Biochemical and pharmacological approaches revealed that H2O2 distribution is mainly controlled by its enzymatic degradation. Here we show that H2O2 is enriched in different regions of the developing brain and demonstrate that it participates to axonal guidance. Retinal ganglion cell axonal projections are impaired upon H2O2 depletion and this defect is rescued by H2O2 or ectopic activation of the Hedgehog pathway. We further show that ex vivo, H2O2 directly modifies Hedgehog secretion. We propose that physiological levels of H2O2 regulate RGCs axonal growth through the modulation of Hedgehog pathway.
•Embryos develop with high levels of H2O2.•High levels of H2O2 are involved in morphogenesis.•H2O2 is involved in nerve growth and guidance during development.•H2O2 regulates Hedgehog signalling.
To characterize the proteomic signature of chronological age, 1,301 proteins were measured in plasma using the SOMAscan assay (SomaLogic, Boulder, CO, USA) in a population of 240 healthy men and ...women, 22–93 years old, who were disease‐ and treatment‐free and had no physical and cognitive impairment. Using a p ≤ 3.83 × 10−5 significance threshold, 197 proteins were positively associated, and 20 proteins were negatively associated with age. Growth differentiation factor 15 (GDF15) had the strongest, positive association with age (GDF15; 0.018 ± 0.001, p = 7.49 × 10−56). In our sample, GDF15 was not associated with other cardiovascular risk factors such as cholesterol or inflammatory markers. The functional pathways enriched in the 217 age‐associated proteins included blood coagulation, chemokine and inflammatory pathways, axon guidance, peptidase activity, and apoptosis. Using elastic net regression models, we created a proteomic signature of age based on relative concentrations of 76 proteins that highly correlated with chronological age (r = 0.94). The generalizability of our findings needs replication in an independent cohort.
Carl Moons and colleagues provide a checklist and background explanation for critically appraising and extracting data from systematic reviews of prognostic and diagnostic prediction modelling ...studies. Please see later in the article for the Editors' Summary.
•Assignment model for networks with advanced traveller information systems (ATIS).•Day-to-day dynamic process for modelling non-equilibrium transients.•Existence, uniqueness and local stability of ...the equilibrium as a fixed-point state.•Small values of ATIS market penetration are enough to ensure the stability.•Small levels of ATIS inaccuracy does not disrupt the stability (numerically proved).
In this paper the stability of traffic equilibrium is analysed by using a framework where advanced traveller information systems (ATIS) are explicitly modelled. The role played by information in traffic networks is discussed, with particular reference to the day-to-day dynamics of the traffic network and to system stability at equilibrium. The perspective adopted is that of transportation planning under recurrent network conditions. The network is considered to be in equilibrium, viewed as a fixed-point state of a day-to-day deterministic process, here modelled as a time-discrete non-linear Markovian dynamic system. In discussing the effects generated by the introduction of ATIS, the paper examines: changes in the fixed point(s) with respect to the absence of ATIS, how the theoretical conditions for fixed-point existence and uniqueness are affected, and the impact on the stability properties and the stability region at equilibrium. Most of the analyses are carried out with explicit theoretical considerations. Moreover, a toy network is also employed to explore numerically the effects of removing some assumptions concerning the accuracy of ATIS.
This study presents a guidance law to intercept non-manoeuvring targets at a desired impact angle. The desired impact angle, defined in terms of a desired line-of-sight angle, is achieved by ...selecting the missile's lateral acceleration to enforce the sliding mode on a sliding surface. Then, the authors use the Lyapunov stability theory to prove the stability of the proposed non-linear sliding surface. Furthermore, they introduce the adaptive neuro-fuzzy inference system (ANFIS) to adaptively update the additional control command and reduce the high-frequency chattering of sliding mode control (SMC). The proposed guidance law, denoted ANFSMC guidance law with impact angle constraint, combines the SMC methodology with ANFIS to enhance the robustness and reduce the chattering of the system. The effectiveness of the ANFSMC guidance law is also verified by the numerical simulations.
Introducción. La orientación universitaria es parte del proceso educativo, entendiéndose como un conjunto de acciones destinadas a proporcionar ayuda continua, sistemática, planificada y organizada a ...los estudiantes por la institución. En España, la orientación universitaria está enmarcada en el modelo formativo del Espacio Europeo de Educación Superior, suponiendo un cambio de modelo y otorgando a los estudiantes un rol activo en su propia formación. El objetivo de esta investigación ha sido describir los sistemas de apoyo y orientación a estudiantes incluidos en el diseño de los nuevos títulos universitarios, elaborados desde 2007. Método. Se ha desarrollado una investigación basada en el análisis de contenido de las memorias de verificación. La muestra recopilada es de 380 memorias de verificación de titulaciones de universidades públicas españolas, seleccionadas por un muestreo aleatorio estratificado de afijación proporcional por universidad y rama. Las memorias de verificación fueron analizadas utilizando el programa MAXQDA, codificándose 44 208 segmentos. Asimismo, se realizó un análisis cuantitativo con el programa SPSS v.26 para determinar las diferencias por año y rama. Resultados. La atención a la dimensión académica es acción más extendida, cubriendo los objetivos de orientar e informar. Las actuaciones son principalmente iniciativas institucionales, estando extensamente implementadas las destinadas a los grupos de estudiantes, especialmente de nuevo ingreso y en los primeros años de universidad. Se ha incrementado la implementación de actuaciones destinadas al estudiantado con necesidades educativas específicas. Discusión. Las universidades públicas españolas realizan actuaciones de apoyo y orientación al estudiantado, constatándose la mejora en la última década en base a análisis previos de necesidades. Mientras que la atención a los grupos de estudiantes se encuentra ampliamente extendida, parece necesario avanzar en la atención a las necesidades específicas de cada individuo.
To improve the quality of care, guidance methodologies can be very helpful for supervisors, practitioners and other stakeholders. A counseling methodology provides an employee with a shared view and ...concrete tools to act more systematically. This enhances acting skills and helps to better respond to specific needs and wishes of clients. This makes working according to methods one of the ways for professionalization. But what exactly is a counseling methodology? Which ones exist in the Netherlands? And for which target groups have they been developed? On the basis of ten criteria, 28 counseling methods were found and summarized. De Grote Methodiekengids, the result of two years of research by Alliade's Department of Applied Scientific Research (PWO), helps to make a choice for each target group on the basis of practical applicability and scientific foundation, among other things. This independent guide is indispensable for supervisors, policy makers, administrators, managers, researchers, remedial educationalists and psychologists in intellectual disability care. De Grote Methodiekengids compiles the available information from public sources and prevents each care facility from having to do comparative methodology research all over again.
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