Dynamics and Steady States in excitable mobile agent systems

We study the spreading of excitations in 2D systems of mobile agents where the excitation is transmitted when a quiescent agent keeps contact with an excited one during a non-vanishing time. We show that the steady states strongly depend on the spatial agent dynamics. Moreover, the coupling between exposition time ($\omega$) and agent-agent contact rate (CR) becomes crucial to understand the excitation dynamics, which exhibits three regimes with CR: no excitation for low CR, an excited regime in which the number of quiescent agents (S) is inversely proportional to CR, and for high CR, a novel third regime, model dependent, here S scales with an exponent $\xi -1$, with $\xi$ being the scaling exponent of $\omega$ with CR

Tweeting about sexism motivates further activism: A social identity perspective

Women, more so than men, are using social media activism to respond to sexism. However, when they do, they are also faced with gendered criticisms (\u27hashtag feminism\u27) that may instead serve to silence them. Based in social identity theory, this research examined how women\u27s social media activism, in response to sexism, may be a first step toward further activism. Two studies used a simulated Twitter paradigm to expose women to sexism and randomly assigned them to either tweet in response, or to a no-tweet control condition. Both studies found support for a serial mediation model such that tweeting after sexism strengthened social identity, which in turn increased collective action intentions, and in turn, behavioural collective actions. Study 2 further showed that validation from others increases the indirect effect of tweeting on behavioural collective action through collective action intentions, but group efficacy did not moderate any indirect effects. It was concluded that when social media activism in response to sexism promotes an enactment of women’s social identity, thereby mobilizing them to further action

Boschi di neoformazione in Italia: approfondimenti conoscitivi e orientamenti gestionali

Nelle regioni meridionali, e in Sicilia in particolare, la fisionomia della vegetazione forestale post-abbandono è quella della macchia o arbusteto che difficilmente evolve verso un bosco propriamente detto. Il processo evolutivo della vegetazione spesso non raggiunge lo stadio di bosco non perché le condizioni ambientali non lo consentano ma per due ragioni fondamentali: i disturbi, in particolare gli incendi e il pascolo, e le limitazioni nell’arrivo di propaguli, causate dalla mancanza di piante madri, dei dispersori dei semi o entrambi. Infatti, in contesti favorevoli (assenza di disturbi e arrivo dei propaguli) la vegetazione evolve sino al bosco. Le formazioni preforestali frutto dei processi di successione secondaria occupano superfici significative e sono conseguenza del fenomeno dell’abbandono dell’agricoltura iniziato alla seconda metà del secolo scorso e che ha interessato tutta l’Europa. Alcune azioni per ridurre i fattori negativi ed esaltare invece i vantaggi ambientali sono possibili per i boschi degli ambienti mediterranei. Tra queste, la trasformazione dei boschi di neoformazione in sistemi agroforestali, e più propriamente silvopastorali, utilizzando la parte aerea delle specie arboree e arbustive e mantenendo piccoli nuclei di specie spontanee utili alla fauna selvatica (a esempio, specie con frutti carnosi) senza lasciare che esse dominino la vegetazione erbacea. Ciò consentirebbe una valorizzazione delle superfici innanzitutto come pascoli, ma non si esclude l’utilizzazione come legna da ardere della componente arborea e, in certi casi, dei prodotti ottenibili (a esempio, manna, mandorle, carrube, nocciole). Altra possibilità per non disperdere i vantaggi consisterebbe nel mettere a coltura gli ex coltivi adottando tecniche alternative che non disperdano il carbonio accumulato. Su questo aspetto esistono già esperienze: ciò potrebbe inoltre ridurre la conflittualità tra gli enti gestori delle aree protette, restii a consentire un ritorno alla coltivazione, e gli agricoltori nonché i sostenitori della necessità di tutelare i paesaggi agrari

Online supervised global path planning for AMRs with human-obstacle avoidance

In smart factories, the performance of the production lines is improved thanks to the wide application of mobile robots. In workspaces where human operators and mobile robots coexist, safety is a fundamental factor to be considered. In this context, the motion planning of Autonomous Mobile Robots is a challenging task, since it must take into account the human factor. In this paper, an implementation of a three-level online path planning is proposed, in which a set of waypoints belonging to a safe path is computed by a supervisory planner. Depending on the nature of the detected obstacles during the robot motion, the re-computation of the safe path may be enabled, after the collision avoidance action provided by the local planner is initiated. Particular attention is devoted to the detection and avoidance of human operators. The supervisory planner is triggered as the detected human gets sufficiently close to the mobile robot, allowing it to follow a new safe virtual path while conservatively circumnavigating the operator. The proposed algorithm has been experimentally validated in a laboratory environment emulating industrial scenarios

Supervised global path planning for mobile robots with obstacle avoidance

The presence of mobile agents in the industrial environment is growing, introducing specific safety issues in their path planning. This paper proposes the implementation of a three-level path planning procedure, which allows: (i) the imposition of a set of waypoints, tending to a safe path, generated by a supervisory planner on the basis of a static map of the environment (not necessarily fully updated), (ii) the generation of a global path including such waypoints exploiting a cost-based algorithm, taking into account also the obstacles not included in the static map, but detected at the beginning of the global planning phase, and (iii) the avoidance of dynamic obstacles appearing during the robot motion, thanks to the action of a local planner. The procedure has been experimentally tested to plan the motion of a differential mobile robot