1,721,058 research outputs found
A Fitness-Sharing based Genetic Algorithm for Collaborative Multi Robot Localization
No full textIn this paper, a novel genetic algorithm based on a “collaborative” fitness-sharing technique to deal with the multi-robot localization problem is proposed. Indeed, the use of the fitness-sharing is twofold and competitive. It preserves the diversity among individuals during the space exploration process, thus maintaining evolutionary niches over time, and reinforces the best hypotheses by means of collaboration among robots, thus augmenting the selection pressure. Simulations by exploiting the robotics framework Player/Stage have been performed along with a proper statistical analysis for performance assessment
Formation control through environment pattern recognition for a multi-robot architecture
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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
Adding and removing nodes in consensus
No full text"The distributed consensus problem has been widely studied in the literature, either with fixed and with time-varying topologies. Typically, the set of agents involved in the consensus does not vary over time. In this paper the possibility to dynamically add or remove nodes during consensus is investigated. Specifically, a framework for the achievement of consensus while dynamically adding nodes to the network is provided, together with a stability condition. Moreover, the effects of removing a single node in the network at a given time instant are inspected, characterizing the difference between the asymptotic values with and without the removed node, depending on the removal time instant. A further result provided in this paper is the relation between the node removal at a given time instant and the initial removal of that node (i.e., at the initial time step).
Ruminal biohydrogenation as affected by tannins in vitro
No full textThe aim of the present work was to study the effects of tannins from carob (CT; Ceratonia siliqua), acacia leaves (AT; Acacia cyanophylla) and quebracho (QT; Schinopsis lorentzii) on ruminal biohydrogenation in vitro. The tannins extracted from CT, AT and QT were incubated for 12 h in glass syringes in cow buffered ruminal fluid (BRF) with hay or hay plus concentrate as a substrate. Within each feed, three concentrations of tannins were used (0·0, 0·6 and 1·0 mg/ml BRF). The branched-chain volatile fatty acids, the branched-chain fatty acids and the microbial protein concentration were reduced (P,0·05) by tannins. In the tannin-containing fermenters, vaccenic acid was accumulated (þ23%, P,0·01) while stearic acid was reduced (216%, P,0·0005). The concentration of total conjugated linoleic acid (CLA) isomers in the BRF was not affected by tannins. The assay on linoleic acid isomerase (LA-I) showed that the enzyme activity (nmol CLA produced/min per mg protein) was unaffected by the inclusion of tannins in the fermenters. However, the CLA produced by LA-I (nmol/ml per min) was lower in the presence of tannins. These results suggest that tannins reduce ruminal biohydrogenation through the inhibition of the activity of ruminal micro-organisms
Basi genetiche e fisiologiche della qualità degli alimenti di origine animale
Full text linkIl miglioramento della qualità dei prodotti rappresenta, da più di vent’anni, uno degli obiettivi prioritari dell’atti- vità di ricerca nell’ambito delle scienze animali, a causa dell’importanza crescente di questo fattore nelle scelte ope- rate dai consumatori. In questo lavoro vengono passati in rassegna i principali alimenti di origine animale (latte, carni e uova), evidenziando lo stato attuale delle conoscenze genetiche e fisiologiche che sono alla base delle loro principali caratteristiche qualitative. In particolare nei bovini e nei suini viene esaminato il ruolo della genetica quantitativa e l’importanza crescente delle conoscenze derivanti dallo studio del genoma animale e dall’individua- zione di QTL, vale a dire loci aventi effetto sui caratteri quantitativi. L’aumento delle conoscenze sulle regioni ge- nomiche che controllano i QTL può consentire di avviare programmi di miglioramento genetico, utilizzando la Se- lezione Assistita da Marcatori (MAS) e l’Introgressione di geni Assistita da Marcatori (MAI). Accanto a queste problematiche vengono riportate le conoscenze relative ai processi fisio-metabolici che determinano la qualità dei prodotti soprattutto riguardo la loro componente lipidica e proteica. In riferimento ai prodotti di altre specie ven- gono analizzate le conoscenze relative alla fisiologia della produzione delle uova e al miglioramento genetico del- le ovaiole e sono ricordati gli aspetti qualitativi più rilevanti delle carni avicole e di coniglio, le particolarità fisio- logiche che condizionano l’espressione di quest’ultime e le metodologie di miglioramento genetico oggi attuate
A Swarm Aggregation Algorithm Based on Local Interaction for Multi-Robot Systems with Actuator Saturation
No full textVariations 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
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