This paper investigates the output consensus problem for heterogeneous linear multi-agent systems via event-triggered control. By introducing a dynamic compensator for each agent, a fully distributed ...event-triggered control strategy with an adaptive event-triggering mechanism is proposed. It is shown that under the proposed control strategy, all agents asymptotically achieve output consensus with intermittent communication in a fully distributed manner. Moreover, with the proposed event-triggering mechanism, Zeno behavior is strictly excluded for each agent. Compared with existing mechanisms, the proposed event-triggering mechanism is independent of any global information and avoids the continuous monitoring issue. Finally, a numerical example is provided to illustrate the effectiveness of the proposed event-triggered control strategy.
This article investigates the cooperative output regulation problem for heterogeneous linear multiagent systems by event-triggered control, where the system matrix of the exosystem is not available ...to all agents. First, an event-triggered adaptive distributed observer is designed for each agent to estimate both the state and the system matrix of the exosystem. Then, a fully distributed event-triggered dynamic output feedback control law is proposed for each agent. Meanwhile, a fully distributed event-triggering mechanism is proposed such that each agent can determine when to broadcast its information to its neighbors. It is shown that with the proposed event-triggered control strategy, the cooperative output regulation problem is solved by intermittent communication in a fully distributed manner in the sense that no global information, such as the eigenvalues of the Laplacian matrix or the number of the agents, is used. It is also shown that Zeno behavior is excluded for each agent. Finally, a numerical example is given to illustrate the effectiveness of the proposed event-triggered control strategy.
This paper investigates the consensus problem of linear multi-agent systems subject to external disturbances via distributed event-triggered adaptive control. First, a distributed event-triggered ...adaptive output feedback control strategy is proposed for each agent. It is shown that under this control strategy, the consensus problem can be solved for any connected undirected communication graph in a fully distributed manner without using any global information. Then a distributed self-triggered adaptive output feedback control strategy is designed with which continuous monitoring of the measurement error is no longer needed. It is further shown that for the proposed event-triggered and self-triggered control strategies, no agent will exhibit Zeno behavior. Finally, the effectiveness of the proposed two control strategies is illustrated on a group of two-mass-spring systems.
A micro-electromechanical system’s reliability depends strongly upon its periodic motion; however, the pull-in instability might arise when the applied voltage is high enough. No criterion is ...available to judge the reliability condition in a simple but effective way. This paper tackles this challenge mathematically. The sufficient conditions for the periodic motion and the pull-in instability of a micro-electromechanical system with a current-carrying conductor are established, respectively. There is an uncertain area, where the system behaves firstly periodic motion, and after a certain number of cycles, the pull-in instability occurs. This new phenomenon is called as a pseudo-pull-in stability (pseudo-periodic motion); its main factors affecting the pseudo-periodic motion are elucidated.
This paper studies the design of distributed adaptive event-triggered control strategies with positive minimum inter-event times for linear multi-agent systems. To present our design idea, this paper ...focuses on the consensus problem of linear multi-agent systems defined on a fixed communication graph. In order to solve the consensus problem, a distributed adaptive event-triggered control strategy is proposed that consists of a distributed event-triggered adaptive control law and a distributed asynchronous event-triggering mechanism. It is shown that under the proposed event-triggered control strategy, the states of all agents asymptotically reach consensus via intermittent communication without using any global information of the communication graph. Moreover, using the proposed event-triggering mechanism, not only the exclusion of the Zeno behavior but also the existence of a uniform strictly positive minimum inter-event time is guaranteed for each agent. A simulation example demonstrates the effectiveness of the proposed event-triggered control strategy.
Rumination is strongly and consistently correlated with depression. Although multiple studies have explored the neural correlates of rumination, findings have been inconsistent and the mechanisms ...underlying rumination remain elusive. Functional brain imaging studies have identified areas in the default mode network (DMN) that appear to be critically involved in ruminative processes. However, a meta-analysis to synthesize the findings of brain regions underlying rumination is currently lacking. Here, we conducted a meta-analysis consisting of experimental tasks that investigate rumination by using Signed Differential Mapping of 14 fMRI studies comprising 286 healthy participants. Furthermore, rather than treat the DMN as a unitary network, we examined the contribution of three DMN subsystems to rumination. Results confirm the suspected association between rumination and DMN activation, specifically implicating the DMN core regions and the dorsal medial prefrontal cortex subsystem. Based on these findings, we suggest a hypothesis of how DMN regions support rumination and present the implications of this model for treating major depressive disorder characterized by rumination.
•Rumination is strongly and consistently correlated with depression.•Meta-analyze the findings of brain regions regarding to rumination.•Specifically examined the contribution of three DMN subsystems to rumination.•Rumination is specifically correlated with the DMN core regions and the dorsal medial prefrontal cortex subsystem.
Azomethine imines, as a prominent class of 1,3‐dipolar species, hold great significance and potential in organic and medicinal chemistry. However, the reported synthesis of centrally chiral ...azomethine imines relies on kinetic resolution, and the construction of axially chiral azomethine imines remains unexplored. Herein, we present the synthesis of axially chiral azomethine imines through copper‐ or chiral phosphoric acid catalyzed ring‐closure reactions of N′‐(2‐alkynylbenzylidene)hydrazides, showcasing high efficiency, mild conditions, broad substrate scope, and excellent enantioselectivity. Furthermore, the biological evaluation revealed that the synthesized axially chiral azomethine imines effectively protect dorsal root ganglia (DRG) neurons by inhibiting apoptosis induced by oxaliplatin, offering a promising therapeutic approach for chemotherapy‐induced peripheral neuropathy (CIPN). Remarkably, the (S)‐ and (R)‐atropisomers displayed distinct neuroprotective activities, underscoring the significance of axial stereochemistry.
The synthesis of axially chiral azomethine imines through copper‐ or chiral phosphoric acid (CPA)‐catalyzed ring closure of N′‐(2‐alkynylbenzylidene)hydrazides is described, showing high efficiency, mild conditions, broad scope, and excellent enantioselectivity. Biological studies revealed the neuroprotective activity of the S product for dorsal root ganglia (DRG) neurons by inhibiting apoptosis induced by oxaliplatin.
Reported herein is the synthesis of benzofused six‐membered S‐heterocycles by intramolecular dehydrogenative C−S coupling using a modular flow electrolysis cell. The continuous‐flow electrosynthesis ...not only ensures efficient product formation, but also obviates the need for transition‐metal catalysts, oxidizing reagents, and supporting electrolytes. Reaction scale‐up is conveniently achieved through extended electrolysis without changing the reaction conditions and equipment.
Electric flow: The synthesis of benzofused six‐membered S‐heterocycles by intramolecular dehydrogenative C−S cross‐coupling has been developed using a modular flow electrolysis cell. The continuous‐flow electrosynthesis not only ensures efficient product formation, but also obviates the need for transition‐metal catalysts, oxidizing reagents, and supporting electrolytes.
This paper investigates the cooperative output regulation problem for heterogeneous linear multiagent systems under fixed communication graphs via event-triggered control. A fully distributed ...event-triggered dynamic output feedback control law is proposed based on the feedforward design approach. At the same time, a fully distributed dynamic event-triggering mechanism is designed so that each agent can determine when to broadcast its information to its neighbors. Compared with existing related results, both the control law and the event-triggering mechanism in this paper are independent of any global information. It is shown that with the proposed dynamic event-triggered control strategy, the cooperative output regulation problem can be solved in a fully distributed manner by intermittent communication. Moreover, Zeno behavior can be strictly ruled out for each agent. Finally, the effectiveness of the proposed dynamic event-triggered control strategy is validated by a numerical example.
An asymmetric synthesis of a series of tricycle‐fused dispirooxindoles frameworks assembled in different rings was disclosed via multicomponent cascade 1,3‐dipolar cycloadditions of ...electron‐deficient 2‐pyrones and trifluoroethylisatin ketimines under the catalysis of hydroquinine or (DHQD)2PHAL with 61→99% ee and >19:1 dr. Meanwhile, these potentially biologically important dispirooxindoles fused pyrrolidinyl/tetrahydropyranone/pyrrolidinyl frame‐works bear eight contiguous stereocenters and functionalized pharmacophores which could further transfer to linaer dispirooxindoles and spirooxindoles bearing epoxyethyl moiety with retentive enantioselectivity.
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