1,720,960 research outputs found
3D Reconstruction Using Two Sonar Devices in a Monte-Carlo Approach for AUV Application
No full textWe propose a sequential method to extract 3-dimensional information for mapping by using sensor fusion of two sonar devices. The 3D reconstruction using sonar images from forward-looking multibeam sonar (FLMS) is an ill-posed problem due to the loss of elevation angle; thus we used an additional sonar and its complementary information. Our approach is to utilize geometric constraints between the installation of two sonar devices and complementary characteristics such as a different angle of the acoustic beams and data acquisition method. The fusion process proceeds in three stages. The first stage is to build a likelihood map using geometric constraints of the installation between two sonar devices. The second stage is to calculate the feasible elevation angle of the FLMS. The elevation angle of FLMS is limited by its vertical beam spreading angle, which can be represented by particles. The third stage is Monte-Carlo experiment using the generated particles by computing the weight, and correct the data of FLMS. To verify the proposed method, we applied the proposed method in simulations and experiments in engineering basin with an AUV.11Nsciescopuskc
Development of a flap-type mooring-less wave energy harvesing system for sensor buoy
No full textTo reduce deployment and maintenance costs, a novel wave energy converter (WEC) is proposed for mooring-less sensor buoys. The design concept is based on a small size WEC capable of harvesting wave energy without mooring, which can reduce the installation cost. The proposed wave energy converter consists of a submerged and a floating body, and the submerged body is a self-rectifying wave-induced turbine that uses the rise and fall of waves to turn a rotor. The rotor of the turbine has flap-type blades, which allows a self-rectifying rotation with rising and falling of waves. In this paper, the dynamics of the system is modeled by hydrodynamic equations, and simulations are carried out based on the dynamic model to determine the optimal design parameters of the system. In addition, the power generation in regular and irregular wave conditions and efficiency in irregular waves of the system are estimated. To verify the results of the simulation, a prototype of the system is implemented and tested in a sea trial. The results demonstrate the feasibility of the proposed wave energy converter. (C) 2017 Elsevier Ltd. All rights reserved.112sciescopu
3D Mapping using Two Sonar devices for AUV Application
No full textWe propose a sequential method to extract 3-dimensional information for mapping by using sensor fusion of two sonar devices. The 3D reconstruction using sonar image from forward scanning sonar (FSS) is an ill-posed problem due to the loss of elevation angle, thus we use additional sonar and its complementary information. Our approach is to utilize geometric constraints between the installation of two sonar devices and complementary characteristics such as a different angle of the acoustic beam, and data acquisition method. To verify the proposed method, we applied the proposed method in simulation and experiment in engineering basin using the developed AUV Cyclops.2
Real-time Wireless Underwater Monitoring System and Neural Network Towards Smart Management of Offshore Fish Farms
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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