1,721,057 research outputs found
Attitude control for a micromechanical flying insect via sensor output feedback
No full textIn this paper, we study attitude stabilization strategies via output sensor feedback for micro aerial vehicles (MAVs), inch-size robots capable of autonomous flight. In order to compensate for the size and power limitations of MAVs, we introduce the ocelli and halteres, the body orientation and rotation sensing mechanisms used by flying insects. The analysis and simulations of these sensors show the feasibility of using such biologically inspired approaches to build biomimetic gyroscopes and angular position detectors. Finally, attitude stabilization techniques based on these sensors are proposed and successfully tested on an aerodynamic model for a micromechanical flying insect (NIFI). To the authors' knowledge, this is the first attempt in using output feedback from biomimetic devices with ocelli and halteres to achieve attitude stabilization in MAVs
Theoretical analysis on the geometries and electronic structures of fluorene-based conjugated polymers
No full textNew fluorene-acceptor random copolymers: Towards pure white light emission from a single polymer
No full textSynthesis and Properties of New Small Band Gap Conjugated Polymers: Methine Bridged Poly(3,4-ethylenedioxypyrrole)
No full textFlapping flight for biomimetic robotic insects: Part I - System modeling
No full textThis paper presents the mathematical modeling of flapping flight inch-size micro aerial vehicles (MAVs), namely micromechanical flying insects (MFIs). The target robotic insects are electromechanical devices propelled by a pair of independent flapping wings to achieve sustained autonomous flight, thereby mimicking real insects. In this paper, we describe the system dynamic models which include several elements that are substantially different from those present in fixed or rotary wing MAVs. These models include the wing-thorax dynamics, the flapping flight aerodynamics at a low Reynolds number regime, the body dynamics, and the biomimetic sensory system consisting of ocelli, halteres, magnetic compass, and optical flow sensors. The mathematical models are developed based on biological principles, analytical models, and experimental data. They are presented in the Virtual Insect Flight Simulator (VIFS) and are integrated together to give a realistic simulation for MFI and insect flight. VIFS is a software tool intended for modeling flapping flight mechanisms and for testing and evaluating the performance of different flight control algorithm
New Fluorene-Pyrazino[2,3-g]quinoxaline-Conjugated Copolymers: Synthesis, Optoelectronic Properties, and Electroluminescence Characteristics
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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