| 1. |
- Leclere, David, et al.
(författare)
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Bending the curve of terrestrial biodiversity needs an integrated strategy
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 585:7826, s. 551-556
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Tidskriftsartikel (refereegranskat)abstract
- Increased efforts are required to prevent further losses to terrestrial biodiversity and the ecosystem services that it provides(1,2). Ambitious targets have been proposed, such as reversing the declining trends in biodiversity(3); however, just feeding the growing human population will make this a challenge(4). Here we use an ensemble of land-use and biodiversity models to assess whether-and how-humanity can reverse the declines in terrestrial biodiversity caused by habitat conversion, which is a major threat to biodiversity(5). We show that immediate efforts, consistent with the broader sustainability agenda but of unprecedented ambition and coordination, could enable the provision of food for the growing human population while reversing the global terrestrial biodiversity trends caused by habitat conversion. If we decide to increase the extent of land under conservation management, restore degraded land and generalize landscape-level conservation planning, biodiversity trends from habitat conversion could become positive by the mid-twenty-first century on average across models (confidence interval, 2042-2061), but this was not the case for all models. Food prices could increase and, on average across models, almost half (confidence interval, 34-50%) of the future biodiversity losses could not be avoided. However, additionally tackling the drivers of land-use change could avoid conflict with affordable food provision and reduces the environmental effects of the food-provision system. Through further sustainable intensification and trade, reduced food waste and more plant-based human diets, more than two thirds of future biodiversity losses are avoided and the biodiversity trends from habitat conversion are reversed by 2050 for almost all of the models. Although limiting further loss will remain challenging in several biodiversity-rich regions, and other threats-such as climate change-must be addressed to truly reverse the declines in biodiversity, our results show that ambitious conservation efforts and food system transformation are central to an effective post-2020 biodiversity strategy. To promote the recovery of the currently declining global trends in terrestrial biodiversity, increases in both the extent of land under conservation management and the sustainability of the global food system from farm to fork are required.
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| 2. |
- Adaldo, Antonio, 1989-, et al.
(författare)
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Event-triggered pinning control of complex networks with switching topologies
- 2014
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Ingår i: Proceedings of the 53rd annual IEEE Conference on Decision and Control. - 9781479977468 ; , s. 2783-2788
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the problem of eventtriggered pinning control for the synchronization of networks of nonlinear dynamical agents onto a desired reference trajectory. The pinned agents are those that have access to the reference trajectory. We consider both static and switching topologies. We prove that the system is well posed and identify conditions under which the network achieves exponential convergence. A lower bound for the rate of convergence is also derived. Numerical examples demonstrating the effectiveness of the results are provided.
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| 3. |
- Adaldo, Antonio, 1989-, et al.
(författare)
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Event-Triggered Pinning Control of Switching Networks
- 2015
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Ingår i: IEEE Transactions on Control of Network Systems. - 2325-5870. ; 2:2, s. 204-213
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates event-triggered pinning control for the synchronization of complex networks of nonlinear dynamical systems. We consider networks described by time-varying weighted graphs and featuring generic linear interaction protocols. Sufficient conditions for the absence of Zeno behavior are derived and exponential convergence of a global normed error function is proven. Static networks are considered as a special case, wherein the existence of a lower bound for interevent times is also proven. Numerical examples demonstrate the effectiveness of the proposed control strategy.
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| 4. |
- Boccia, Antonio, et al.
(författare)
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Tracking a mobile target by multi-robot circumnavigation using bearing measurements
- 2017
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Ingår i: 2017 IEEE 56th Annual Conference on Decision and Control, CDC 2017. - : IEEE. - 9781509028733 ; , s. 1076-1081
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study a problem of target tracking and circumnavigation with a network of autonomous agents. We propose a distributed algorithm to estimate the position of the target and drive the agents to rotate around it while forming a regular polygon and keeping a desired distance. We formally show that the algorithm attains exponential convergence of the agents to the desired polygon if the target is stationary, and bounded convergence if the target is moving with bounded speed. Numerical simulations corroborate the theoretical results and demonstrate the resilience of the network to addition and removal of agents.
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| 5. |
- Cavaliere, Clara, et al.
(författare)
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Cloud-supported self-triggered control for multi-agent circumnavigation
- 2018
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Ingår i: 2018 IEEE CONFERENCE ON DECISION AND CONTROL (CDC). - : IEEE. - 9781538613955 ; , s. 5090-5095
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a cloud-supported control framework for multi-agent circumnavigation missions. We consider a network of planar autonomous agents. Our objective is for the agents to circumnavigate a target with a desired angular speed, while forming a regular polygon around the target. We propose self-triggered rules to schedule the bearing measurements and the cloud accesses for each agent.
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| 6. |
- Di Bernardo, Mario, et al.
(författare)
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Contraction analysis for a class of nondifferentiable systems with applications to stability and network synchronization
- 2014
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Ingår i: SIAM Journal of Control and Optimization. - : Society for Industrial & Applied Mathematics (SIAM). - 0363-0129 .- 1095-7138. ; 52:5, s. 3203-3227
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we extend to a generic class of piecewise smooth dynamical systems a fundamental tool for the analysis of convergence of smooth dynamical systems: contraction theory. We focus on switched nondifferentiable systems satisfying Caratheodory conditions for the existence and uniqueness of a solution. After generalizing the classical definition of contraction to this class of dynamical systems, we give sufficient conditions for global convergence of their trajectories. The theoretical results are then applied to solve a set of representative problems such as proving global asymptotic stability of switched linear systems, giving conditions for incremental stability of piecewise smooth systems, and analyzing the convergence of networked switched systems.
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| 7. |
- Di Bernardo, Mario, et al.
(författare)
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On the robustness of periodic solutions in relay feedback systems
- 2002
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Ingår i: Proceedings of the 15th IFAC World Congress, 2002. - : IFAC.
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Konferensbidrag (refereegranskat)abstract
- Structural robustness of limit cycles in relay feedback systems is studied. Motivated by a recent discovery of a novel class of bifurcations in these systems, it is illustrated through numerical simulation that small relay perturbations may change the appearance of closed orbits dramatically. It is shown analytically that certain stable periodic solutions in relay feedback systems are robust to relay perturbations.
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| 8. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Lamb, Maurice, et al.
(författare)
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To Pass or Not to Pass : Modeling the Movement and Affordance Dynamics of a Pick and Place Task
- 2017
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Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Humans commonly engage in tasks that require or are made more efficient by coordinating with other humans. In this paper we introduce a task dynamics approach for modeling multi-agent interaction and decision making in a pick and place task where an agent must move an object from one location to another and decide whether to act alone or with a partner. Our aims were to identify and model (1) the affordance related dynamics that define an actor’s choice to move an object alone or to pass it to their co-actor and (2) the trajectory dynamics of an actor’s hand movements when moving to grasp, relocate, or pass the object. Using a virtual reality pick and place task, we demonstrate that both the decision to pass or not pass an object and the movement trajectories of the participants can be characterized in terms of behavioral dynamics model. Simulations suggest that the proposed behavioral dynamics model exhibits features observed in human participants including hysteresis in decision making, non-straight trajectories, and non-constant velocity profiles. The proposed model highlights how the same low-dimensional behavioral dynamics can operate to constrain multiple (and often nested) levels of human activity and suggests that knowledge of what, when, where and how to move or act during pick and place behavior may be defined by these low dimensional task dynamics and, thus, can emerge spontaneously and in real-time with little a priori planning.
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| 10. |
- Liuzza, Davide, et al.
(författare)
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Distributed model based event-triggered control for synchronization of multi-agent systems
- 2016
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Ingår i: Automatica. - : Elsevier. - 0005-1098 .- 1873-2836. ; 73, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the problem of event-triggered control for the synchronization of networks of nonlinear dynamical agents; distributed model-based approaches able to guarantee the synchronization of the overall system are derived. In these control schemes all the agents use a model of their neighbourhood in order to generate triggering instants in which the local controller is updated and, if needed, local information based on the adopted control input is broadcasted to neighbouring agents, Synchronization of the network is proved and the existence of Zeno behaviour is excluded; an event triggered strategy able to guarantee the existence of a minimum lower bound between inter-event times for broadcasted information and for control signal updating is proposed, thus allowing applications where both the communication bandwidth and the maximum updating frequency of actuators are critical. This idea is further extended in an asynchronous periodic event-triggered schemes where the agents check a trigger condition via a periodic distributed communication without requiring a model based computation.
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