1,723,690 research outputs found
Introduction
No full textThe current desire to go and explore space is as strong as ever. Past space powers have been gradually joined by a flurry of new nations eager to test and demonstrate their technologies and contribute to an increasing body of knowledge. Space robotics and autonomous systems (RAS) are important to human's overall ability to explore or operate in space, by providing greater access beyond human spaceflight limitations in the harsh environment of space and operational handling that extends astronauts' capabilities. RAS can help reduce the cognitive load on humans given the abundance of information that has to be reasoned upon in a timely fashion and hence are critical for improving human and systems' safety. RAS can also enable the deployment and operation of multiple assets without the same order of magnitude increase in ground support. Given the potential reduction to the cost and risk of spaceflight both manned and robotic, space RAS are deemed relevant across all mission phases such as development, flight system production, launch, and operation. This chapter introduces the book by providing the basis of space RAS, such as key technological challenges, relevant applications over the horizon as well as the recent advances to be presented in the remainder of the book
Autonomous robotic grasping in orbital environment
No full textCapturing a target will always be a crucial part of any orbital activity for space robots. This chapter aims to present an overview of the developed technologies and algorithms that enable a robot to grasp a target in microgravity. Studies on human grasping in microgravity are described both for providing a solid background on orbital grasping and as inspiration for the development of robotic systems to aid astronauts. The chapter also describes the most important past and future applications of target capturing with robotic arms. The core analysis of the chapter consists of a large number of studies and engineering milestones on orbital robotic capturing that are categorised based on the means of interaction with the target, as well as reporting the state-of-the-art grasping methods. A number of important missions that have grasping as their basic demonstrated technology are also presented. The chapter ends with outlining the most important physical, algorithmic, and operational challenges in orbital robotic grasping, and setting up the capabilities that future robotic systems need to possess
Autonomous visual navigation for spacecraft on-orbit operations
No full textSpace robotic missions with increased levels of autonomy are being pursued in wide-array of orbital applications including on-orbit servicing (OOS), on-orbit assembly (OOA), and active debris removal (ADR). In these missions, the spacecraft is expected to perform most guidance and navigation tasks such as far-, mid- and close-range rendezvous, relative navigation, and proximity operations with minimal human-in-loop. This goal brings the focus towards vision-based spacecraft navigation utilising the state-of-the-art technologies in the field of computer vision especially the deep-learning algorithms for the pose estimation. This chapter explores major deep-learning approaches suitable for spacecraft pose estimation along with the discussion on different software simulation tools that are currently used for rendering realistic images of the target in orbit to train and validate the deep-learning models, and finally the ground-based testbed is used for validating the close-proximity operations
Biologically-inspired mechanisms for space applications
No full textNatural organisms are constantly having to adapt in order to overcome the challenges posed by their environment, with the most beneficial traits being continuously improved and refined over millions of years of evolution. This long refinement process takes place at all scale levels, from the nano to the macroscopic, resulting in materials and processes far superior to human solutions to similar problems. As such, studying these natural techniques and adapting them for man-made applications can lead to innovations and new improvements in current and future technologies
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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