1,721,026 research outputs found
Reinforcement Learning based Omnidirectional Vision Agent for Mobile Robot Navigation
No full textThis paper presents an Omnidirectional Vision Agent able to learn to navigate a mobile robot in its working environment. The novelty of the work is the application of Reinforcement Learning paradigm to Vision Agents aiming to develop a totally autonomous system able to learn control policies by on-line learning, to deal with changing environment and to improve its performance dur- ing lifetime. SARSA(λ) method is used by the Vision Agent to learn the con- trol policy for the robot. The LEM strategy is also applied to speed up learning. The knowledge acquired by one Vision Agent is then “copied” to another Vision Agent in a network of cameras implementing a Distributed Vision System (DVS). By copying the knowledge the aim is both reducing learning time and exploiting the knowledge already learned. Since our prime interest was to investigate how the Vision Agent learns the knowledge by using SARSA(λ) and to evaluate its performance, we carried out the experimentation in simulation. The good results obtained during the experimental phase are very encouraging to transfer all the experimentation in a real context
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
Explicit Knowledge Distribution in an Omnidirectional Distributed Vision System
No full textThis paper presents an omnidirectional distributed vision system that learns to navigate a robot in an office-like environment without any knowledge about the calibration of the cameras or the robot control law. The system is composed of several omnidirectional vision agents (implemented with an omnidirectional camera and a computer). The first vision agent learns to control the robot with SARSA(λ) reinforcement learning, using the LEM strategy to speed-up learning. Once the first vision agent learnt the correct policy, it transfers its knowledge to the other vision agents. The other vision agents might have different intrinsic and extrinsic camera parameters (that are unknown), so a certain amount of re-learning is needed. Reinforcement learning is well suited for this. In this paper, we present the structure of the learning system and the discussion about the optimal values for the learning parameters. During the experimentation the learning phase of the first agent has been carried out, then the knowledge propagation and the re-learning stage of three different agents have been tested. The experimental results demonstrate the feasibility of the approach and the possibility to port the system on the actual robot and cameras
Multi-Sensor Surveillance of Indoor Environments by an Autonomous Mobile Robot
No full textIn this paper, we present our autonomous mobile robotic system for surveillance of indoor environments. The robot is equipped with a monocular camera, a laser scanner, encoders, and an RFID device, connected to a multi-layer decision and control scheme. Two main functions are implemented: to build a map of the environment, identifying specific areas of interest, marked by RFID tags; to monitor the target zones to detect unexpected changes, such as object addition or removal, based on a Vision Scene Change Detector (V-SCD) and a Laser Scene Change Detector (L-SCD). Fuzzy logic is used to integrate information provided by the different sensors. Applications of the proposed system include surveillance of wide areas, such as airports and museums, and monitoring of safety equipment. The feasibility of the approach is demonstrated through experimental tests, performed in the ISSIA Mobile Robotics Laboratory of Bari, Italy. The results are promising, proving the method to be effective in detecting either new or removed objects in the surveyed scene, also in presence of relatively small viewpoint changes. It is shown that the proposed robotic surveillance system successfully addresses a number of specific problems related to environment mapping, autonomous navigation, and scene processing, and can be potentially employed in real world surveillance applications
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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