360 research outputs found
Cooperative Simultaneous Tracking and Jamming for Disabling a Rogue Drone
This work investigates the problem of simultaneous tracking and jamming of a
rogue drone in 3D space with a team of cooperative unmanned aerial vehicles
(UAVs). We propose a decentralized estimation, decision and control framework
in which a team of UAVs cooperate in order to a) optimally choose their
mobility control actions that result in accurate target tracking and b) select
the desired transmit power levels which cause uninterrupted radio jamming and
thus ultimately disrupt the operation of the rogue drone. The proposed decision
and control framework allows the UAVs to reconfigure themselves in 3D space
such that the cooperative simultaneous tracking and jamming (CSTJ) objective is
achieved; while at the same time ensures that the unwanted inter-UAV jamming
interference caused during CSTJ is kept below a specified critical threshold.
Finally, we formulate this problem under challenging conditions i.e., uncertain
dynamics, noisy measurements and false alarms. Extensive simulation experiments
illustrate the performance of the proposed approach.Comment: 2020 IEEE/RSJ International Conference on Intelligent Robots and
Systems (IROS
Joint Estimation and Control for Multi-Target Passive Monitoring with an Autonomous UAV Agent
This work considers the problem of passively monitoring multiple moving
targets with a single unmanned aerial vehicle (UAV) agent equipped with a
direction-finding radar. This is in general a challenging problem due to the
unobservability of the target states, and the highly non-linear measurement
process. In addition to these challenges, in this work we also consider: a)
environments with multiple obstacles where the targets need to be tracked as
they manoeuvre through the obstacles, and b) multiple false-alarm measurements
caused by the cluttered environment. To address these challenges we first
design a model predictive guidance controller which is used to plan
hypothetical target trajectories over a rolling finite planning horizon. We
then formulate a joint estimation and control problem where the trajectory of
the UAV agent is optimized to achieve optimal multi-target monitoring
IMP-MARL: a Suite of Environments for Large-scale Infrastructure Management Planning via MARL
We introduce IMP-MARL, an open-source suite of multi-agent reinforcement
learning (MARL) environments for large-scale Infrastructure Management Planning
(IMP), offering a platform for benchmarking the scalability of cooperative MARL
methods in real-world engineering applications. In IMP, a multi-component
engineering system is subject to a risk of failure due to its components'
damage condition. Specifically, each agent plans inspections and repairs for a
specific system component, aiming to minimise maintenance costs while
cooperating to minimise system failure risk. With IMP-MARL, we release several
environments including one related to offshore wind structural systems, in an
effort to meet today's needs to improve management strategies to support
sustainable and reliable energy systems. Supported by IMP practical engineering
environments featuring up to 100 agents, we conduct a benchmark campaign, where
the scalability and performance of state-of-the-art cooperative MARL methods
are compared against expert-based heuristic policies. The results reveal that
centralised training with decentralised execution methods scale better with the
number of agents than fully centralised or decentralised RL approaches, while
also outperforming expert-based heuristic policies in most IMP environments.
Based on our findings, we additionally outline remaining cooperation and
scalability challenges that future MARL methods should still address. Through
IMP-MARL, we encourage the implementation of new environments and the further
development of MARL methods
Integrated Ray-Tracing and Coverage Planning Control using Reinforcement Learning
In this work we propose a coverage planning control approach which allows a
mobile agent, equipped with a controllable sensor (i.e., a camera) with limited
sensing domain (i.e., finite sensing range and angle of view), to cover the
surface area of an object of interest. The proposed approach integrates
ray-tracing into the coverage planning process, thus allowing the agent to
identify which parts of the scene are visible at any point in time. The problem
of integrated ray-tracing and coverage planning control is first formulated as
a constrained optimal control problem (OCP), which aims at determining the
agent's optimal control inputs over a finite planning horizon, that minimize
the coverage time. Efficiently solving the resulting OCP is however very
challenging due to non-convex and non-linear visibility constraints. To
overcome this limitation, the problem is converted into a Markov decision
process (MDP) which is then solved using reinforcement learning. In particular,
we show that a controller which follows an optimal control law can be learned
using off-policy temporal-difference control (i.e., Q-learning). Extensive
numerical experiments demonstrate the effectiveness of the proposed approach
for various configurations of the agent and the object of interest.Comment: 2022 IEEE 61st Conference on Decision and Control (CDC), 06-09
December 2022, Cancun, Mexic
Distributed Search Planning in 3-D Environments With a Dynamically Varying Number of Agents
In this work, a novel distributed search-planning framework is proposed,
where a dynamically varying team of autonomous agents cooperate in order to
search multiple objects of interest in three-dimension (3-D). It is assumed
that the agents can enter and exit the mission space at any point in time, and
as a result the number of agents that actively participate in the mission
varies over time. The proposed distributed search-planning framework takes into
account the agent dynamical and sensing model, and the dynamically varying
number of agents, and utilizes model predictive control (MPC) to generate
cooperative search trajectories over a finite rolling planning horizon. This
enables the agents to adapt their decisions on-line while considering the plans
of their peers, maximizing their search planning performance, and reducing the
duplication of work.Comment: IEEE Transactions on Systems, Man, and Cybernetics: Systems, 202
Geomiso TNL: A Software for Non-Linear Static T-Spline-Based Isogeometric Analysis of Complex Multi-Patch Structures
A new software, Geomiso TNL, is proposed to facilitate the use of isogeometric analysis and 3D design with NURBS and T-splines. Its dual nature eliminates geometric errors by merging geometric design with mesh generation into a single procedure. It is based on the isogeometric method, the powerful generalization of the traditional finite element method. This paper presents four sample applications in non-linear solid and structural mechanics. This software is seen to handle these situations remarkably well, as the numerical examples exhibit significantly improved accuracy of the results, such as displacement, strain and stress fields, and reduced computational cost when compared with finite element analysis. It is argued that Geomiso TNL is a new, more efficient, alternative to finite element software packages and possesses several advantages
IL-4 receptor engagement in human neutrophils impairs their migration and extracellular trap formation
Background
Type 2 immunity serves to resist parasitic helminths, venoms, and toxins, but the role and regulation of neutrophils during type 2 immune responses are controversial. Helminth models suggested a contribution of neutrophils to type 2 immunity, whereas neutrophils are associated with increased disease severity during type 2 inflammatory disorders, such as asthma.
Objective
We sought to evaluate the effect of the prototypic type 2 cytokines IL-4 and IL-13 on human neutrophils.
Methods
Human neutrophils from peripheral blood were assessed without or with IL-4 or IL-13 for (1) expression of IL-4 receptor subunits, (2) neutrophil extracellular trap (NET) formation, (3) migration toward CXCL8 in vitro and in humanized mice, and (4) CXCR1, CXCR2, and CXCR4 expression, as well as (5) in nonallergic versus allergic subjects.
Results
Human neutrophils expressed both types of IL-4 receptors, and their stimulation through IL-4 or IL-13 diminished their ability to form NETs and migrate toward CXCL8 in vitro. Likewise, in vivo chemotaxis in NOD-scid-Il2rg−/− mice was reduced in IL-4–stimulated human neutrophils compared with control values. These effects were accompanied by downregulation of the CXCL8-binding chemokine receptors CXCR1 and CXCR2 on human neutrophils on IL-4 or IL-13 stimulation in vitro. Ex vivo analysis of neutrophils from allergic patients or exposure of neutrophils from nonallergic subjects to allergic donor serum in vitro impaired their NET formation and migration toward CXCL8, thereby mirroring IL-4/IL-13–stimulated neutrophils.
Conclusion
IL-4 receptor signaling in human neutrophils affects several neutrophil effector functions, which bears important implications for immunity in type 2 inflammatory disorders
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