1,720,957 research outputs found
Hardware variation in robotic swarm and behavioural sorting with swarm chromatography
No full textSocial insects can achieve remarkable outcomes, various examples can be found in ants, bees, etc. Inspired by social insects, swarm robotic research considers coordinating a group of relatively simple and autonomous robots to finish tasks collaboratively based on direct or indirect interactions. Such systems can offer advantages of robustness, flexibility and scalability, just like social insects.For many years, various researchers have endeavoured to design intelligent artificial swarms and many hardware-based swarm robots have been implemented. One assumption that made by a majority of swarm robotic researchers, particularly in software simulation is that a robotic swarm is a group of identical robots, there is no difference between any two of them. However, differences among hardware robots are unavoidable, which exist in robotic sensors, actuators, etc. These hardware differences, albeit small, can affect the robots’ response to the environment. Moreover, hardware differences can provoke robots’ heterogeneity which then profoundly influence swarm performance due to the non-linearity in the controller and uncertainty in the environment. Nevertheless, questions about how hardware differences influence swarm performance and how to make use of them remain a research challenge.In this work, the issue of hardware variation in swarm robots is investigated. Specifically swarm robots with hardware variations are modelled and simulated in a line following scenario. It is found that even small hardware variations can result in behavioural heterogeneity. Although the variations can be compensated by the software controller in training, the hardware variations and resulting differences in training are amplified in the interactions between the robot and the environment.To know how exactly hardware variation influence robotic behaviours, a novel approach, inspired by the chromatography method in chemistry, is proposed to sort swarm robots according to their hardware circumstances. This method is based on a large number of interactions between robots and the environment. Individual robot’s unique hardware circumstance determines its unique decision making and reaction during each robotic controlling step, and these unique microscopic reactions accumulate and contribute to the robot’s macroscopic behaviour. The behavioural sorting results show that the behaviour of an individual robot is not determined by a single parameter but by the combination of multiple hardware factors. Different combinations of hardware parameters can help robots achieve similar behaviours.The efficiency of the behavioural sorting method is investigated, particularly the influence of the robot’s controller and environmental factor. By simulating various combinations of robots with different integration lengths of the controller and arenas with different pattern densities, it is discovered that if the robots’ ability to memorise previous events is coupled with the density of the sorting arena, better sorting results can be achieved.This work is regarded as an initial investigation into the issue of unavoidable hardware differences between swarm robots. Given the research outcome and that real swarms will necessarily show hardware variations, it is therefore necessary to contemplate current swarm algorithms in the context of diverse robot populations. In addition, a new research field of swarm chromatography for sorting robotic behaviours to improve swarm efficiency is initiated
An approach to sorting swarm robots to optimize performance
No full textSwarm robotic systems can offer many advantages including robustness, flexibility and scalability. However one of the issues relating to overall swarm performance that needs to be considered is hardware variations inherent in the implementation of individual swarm robots. This variation can bring behavioral diversity within the swarm, resulting in uncontrollable swarm behaviors, low efficiency, etc. If swarm robots could be separated by behaviors, operational advantages could be obtained. In this paper we report an approach to the sorting of large robotic swarms using an approach inspired by chromatography. Hence the tedious and expensive calibration process can be avoided. The results investigate the influence of the internal control parameters, together with environmental effects on the robotic behavioral sorting. We concluded that if the robot has knowledge of previous events coupled with a specific arena pattern density will offer improved behavioral sorting
Swarm behavioral sorting based on robotic hardware variation
No full textSwarm robotic systems can offer advantages of robustness, flexibility and scalability, just like social insects. One of the issues that researchers are facing is the hardware variation when implementing real robotic swarms. Identical software cannot guarantee identical behaviors among all robots due to hardware differences between swarm members. We propose a novel approach for sorting swarm robots according to their hardware differences. This method is based on the large number of interactions between robots and the environment. Individual robot’s unique hardware circumstance determines its unique decision and reaction during each robotic controlling step, and these unique local reactions accumulate and contribute to the robot’s global behavior. Accordingly by separating these hardware-triggered global behaviors, swarm robots can be sorted according to their hardware variations
Simulation of hardware variations in swarm robots
Full text linkSwarm robotic systems can offer advantages of robustness, flexibility and scalability, just like social insects. One assumption that is made by the majority of swarm robotic researchers, particularly in software simulation, is that a robotic swarm is a group of identical robots, there is no difference between any two of them. However, differences among hardware robots are unavoidable. These hardware differences, albeit small, affect the robots response to its environment. In this work, robots with hardware variation have been modeled and simulated in a line following scenario. It is found that even small hardware variations can result in behavioral heterogeneity. Although the variations can be compensated by the controllers in training, the hardware variation and resulting differences in controller settings are amplified in the non-linear interaction between robot and environment. Accordingly, the behavior of the identically trained robots in the same environment are subject to divergence
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
- …
