1,720,972 research outputs found
Development of Integrated Digging Robot using Drill Bit-Limbs Hybrid Mechanism that Mimics Burrowing Animals Behavior
No full textOver the last few years, drilling system has been extensively used for a miscellaneous number of applications. However, in certain applications, e.g., shallow drilling and excavation on a difficult or rugged terrain, excavation using conventional drilling methods are not applicable. Considering the aggravating obstacles of drill bit application, in this study, digging attitude of burrowing animals (rabbits and moles) is studied. The soil penetrating force developed by burrowing animals, nevertheless, is indeed inadequate for harder and deeper excavation. Therefore, to overcome the aforementioned issues, this paper proposes a hybrid digging mechanism by combining the advantage of employing a drill bit and forelimbs mechanism adapted from burrowing animals. Emulating the role of their teeth, triangle-shaped drill bit, i.e., step drill bit, is exploited and a linkage mechanism is utilized to represent their digging motion using limbs. Dynamic simulation is performed to evaluate the digging performance of this robo
Development of Wall-climbing Unmanned Aerial Vehicle System for Micro-Inspection of Bridges
No full textThe field of research for bridge inspection using a UAV has gradually been developed to meet human needs. The UAV-based inspection system can be classified into contact-type and non-contact-type inspection depending on the purpose of the tests. In this paper, we propose a contact-type UAV system that can move close to the surface for micro inspection of the bridge. In the early development of CAROS (Climbing Aerial Robot System), the platform was depending on thrust and friction force, which leads to a limitation that it was difficult to obtain the force required for wall movement under the low friction coefficient. To compensate for this, we introduce the enhancement of CAROS, which has improved the shortcomings of dependence on the wall friction force by applying an auxiliary arm and a tilt-rotor mechanism and changing the direction of propulsion. The proposed system is prototyped and the climbing ability on the wall, with and without obstacles, in various slopes is validated
LVI-Q: Robust LiDAR-Visual-Inertial-Kinematic Odometry for Quadruped Robots Using Tightly-Coupled and Efficient Alternating Optimization
No full textAutonomous navigation for legged robots in complex and dynamic environments relies on robust simultaneous localization and mapping (SLAM) systems to accurately map surroundings and localize the robot, ensuring safe and efficient operation. While prior sensor fusion-based SLAM approaches have integrated various sensor modalities to improve their robustness, these algorithms are still susceptible to estimation drift in challenging environments due to their reliance on unsuitable fusion strategies. Therefore, we propose a robust LiDAR-visual-inertial-kinematic odometry system that integrates information from multiple sensors, such as a camera, LiDAR, inertial measurement unit (IMU), and joint encoders, for visual and LiDAR-based odometry estimation. Our system employs a fusion-based pose estimation approach that runs optimization-based visual-inertial-kinematic odometry (VIKO) and filter-based LiDAR-inertial-kinematic odometry (LIKO) based on measurement availability. In VIKO, we utilize the foot-preintegration technique and robust LiDAR-visual depth consistency using superpixel clusters in a sliding window optimization. In LIKO, we incorporate foot kinematics and employ a point-to-plane residual in an error-state iterative Kalman filter (ESIKF). Compared with other sensor fusion-based SLAM algorithms, our approach shows robust performance across public and long-term datasets.
Autonomous Macro and Micro Bridge Inspection Using Aerial Vehicle Capable of Wall-Climbing
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
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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