Search

A flurry of regulations has emerged across the world to govern the use, transfer and storage of data, affecting digital and traditional firms, of all sizes. To guide business practitioners and educators, this article provides insights into key components of digital laws and what they mean for different types of firms. We take the European Union as starting point, given its prominent and extra-territorial rule-setting, but also reflect on other cross-border (future) digital regulations. Our analysis of relevant details reveals a need for practitioners to be prepared and forward-looking, considering firms' specifics, internationally converging ethical principles and (future) digitally-aware generations. [ABSTRACT FROM AUTHOR]

In a context of extraordinary and incredibly fast-paced development, artificial intelligence (AI) breaks into the daily routine of all of us, pledging to bring great benefits to those who want to exploit it. If on the one hand the positive aspects are undeniable, on the other hand it is clear how an improper use of AI can have a significant impact in the real world if adequate security controls are not enforced. Indeed, the strategy the AI adopts in making decisions, especially in the case of recent generative language models, is not directly under human control, and potentially depends on the specific scenario in which AI is applied, yielding possible non-negligible security and safety concerns. In this article, after having introduced the fundamentals of the so-called AI ecosystem, we will analyze in detail the AI governance macro-processes aimed at guaranteeing the cybersecurity of the ecosystem itself, ranging from the management of cyber-risks introduced by AI to research and innovation programs, focusing on the Italian setting. We will also describe some notable use cases where AI comes in support of cybersecurity, before concluding with some insights into possible future developments in this field. [ABSTRACT FROM AUTHOR]

We live in a digitalised reality, where many activities depend on interconnected technological systems. A real cyber transition that offers the prospect of evolution and progress, but also exposes users to unprecedented threats in the field of digital security and fundamental rights. Therefore, cybersecurity regulation is imperative for containing potentially damaging cyber-attacks on infrastructures. For these same purposes, it is equally critical to consider the role that users play (i.e. the human factor). [ABSTRACT FROM AUTHOR]

The noble metal Pt is an ideal catalyst for promoting the hydrogen evolution reaction (HER) during the electrolysis of water. However, Pt is also expensive and suffers from low utilization rates. In this work, a Pt-Ni 2 P/NF nanorod catalyst with a low Pt loading was synthesized under different magnetic fields, and it was found that the application of a magnetic field can increase the rate of the galvanic replacement reaction. When the magnetic field strength increases from 0 to 600 mT, the chemical reaction rate increases gradually, and the utilization rate of Pt increased by 2.3 times under 600 mT. The mechanism of the magnetic field-induced magnetohydrodynamic (MHD) effect on the galvanic replacement reaction was revealed. In a 1 M KOH solution and at a current density of 10 mA cm–2, the overpotential of Pt-Ni 2 P/NF prepared by applying a 600 mT magnetic field was as low as 15 mV and the Tafel slope was 37 mV dec–1, compared with values of 82 mV and 70 mV dec–1 for a specimen prepared without a magnetic field. Additionally, at an overpotential of 90 mV, the mass-based Pt activity of the former material was 12 times greater while its turnover frequency was 19 times greater. This work provides theoretical and technical knowledge expected to assist in the controllable preparation of materials in magnetic fields and the efficient utilization of metallic resources. [Display omitted] [ABSTRACT FROM AUTHOR]

Water scarcity and security drive attention to water reuse in policy and business. However, water reuse may generate new water loops and challenge water governance with new and different types of water, risks, involved actors, and responsibilities. These challenges demand robust institutional arrangements related to water governance. This article assesses the institutional arrangements associated with four case studies in Spain, Italy, Croatia, and Israel. The findings reveal that the more diverse the water uses and users, the more challenges and risks, particularly those associated with institutional arrangements such as quality standards, sanctions, and conflict prevention, are likely to emerge. The weaknesses of governance models and regulations to deal with changes, uncertainties, and public resistance call for special attention to the design of the institutional arrangements before the adoption. Independent of the type of technology adopted, governance may be improved by ensuring internal and external water monitoring; integrating water management with spatial concerns; improving training, expert engagement, and civil society awareness; and reducing water reuse costs. In addition, alternative models that guarantee the efficiency of governance in attaining objectives and assuring the participation of new water users in the management of water reuse loops may also improve governance. [ABSTRACT FROM AUTHOR]

This article seeks to examine three important questions: What challenges does the virtual world pose for competition law? In what way does the digital economy change the relationship between economic rights and fundamental freedoms? How does the digital economy affect the division of jurisdiction between independent authorities? Two responses to these questions are suggested. The first and more radical is to introduce new laws to redesign competition law, jurisdictions, and intertwining rights. The second is a more sophisticated solution, namely, to interpret existing laws in the light of technological changes, coherent with an evolutionary interpretation of national and European Constitutional frameworks. In either case, it must be assumed as a political necessity that Europe's primary purpose is to guide the digital revolution in the direction of equality for citizens in the exercise of economic rights and fundamental freedoms. [ABSTRACT FROM AUTHOR]

Animal protection laws exist at federal, provincial and municipal levels in Canada, with enforcement agencies relying largely upon citizens to report concerns. Existing research about animal protection law focuses on general approaches to enforcement and how legal terms function in the courts, but the actual work processes of animal law enforcement have received little study. We used institutional ethnography to explore the everyday work of Call Centre operators and Animal Protection Officers, and we map how this work is organised by laws and institutional polices. When receiving and responding to calls staff try to identify evidence of animal 'distress' as legally defined, because various interventions (writing orders, seizing animals) then become possible. However, many cases, such as animals living in deprived or isolated situations, fall short of constituting 'distress' and the legally mandated interventions cannot be used. Officers are also constrained by privacy and property law and by the need to record attempts to secure compliance in order to justify further action including obtaining search warrants. As a result, beneficial intervention can be delayed or prevented. Officers sometimes work strategically to advocate for animals when the available legal tools cannot resolve problems. Recommendations arising from this research include expanding the legal definition of 'distress' to better fit animals' needs, developing ways for officers to intervene in a broader range of situations, and more ethnographic research on enforcement work in jurisdictions with different legal systems to better understand how animal protection work is organised and constrained by laws and policies. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin de l'Académie Vétérinaire de France is the property of Academie Veterinaire de France and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin de l'Académie Vétérinaire de France is the property of Academie Veterinaire de France and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vodafone UK and Three UK have made further commitments as part of efforts to secure regulatory approval for their proposed merger. [ABSTRACT FROM AUTHOR]

When discrete-time Markov jump linear systems are prone to the damaging effects of polytopic uncertainties, it is necessary to address all the vertices of each Markov mode in order to properly design robust controllers. To this end, we propose a robust recursive linear–quadratic regulator for this class of systems. We define a quadratic min–max optimization problem by combining least-squares and penalty functions in a unified framework. We design a one-step cost function to encompass the entire set of vertices of each mode altogether, while maintaining its quadratic structure and the convexity of the problem. The solution is then obtained recursively and does not require numerical optimization packages. We establish conditions for convergence and stability by extending the matrix structure of the recursive solution. In addition, we provide numerical and real-world application examples to validate our method and to emphasize recursiveness and diminished computational effort. [ABSTRACT FROM AUTHOR]

This article investigates the robust cooperative output regulation problem of heterogeneous uncertain linear multiagent systems with switching topologies and infinite distributed communication delays. A novel distributed observer is proposed for each agent to estimate the state of the so-called exosystem by taking consideration of both switching topologies and infinite distributed communication delays. A distributed output feedback controller is then developed based on the internal model principle and the estimated state without using the prior knowledge of communication delays. It is shown via the newly developed Lyapunov-like method that the robust cooperative output regulation problem can be solved under some mild assumptions. Finally, a numerical example is given to demonstrate the effectiveness of the proposed controller. [ABSTRACT FROM AUTHOR]

This article investigates the output feedback setpoint regulation control of a reaction–diffusion equation by means of boundary control. The considered reaction–diffusion plant may be open-loop unstable. The proposed control strategy consists of the coupling of a finite-dimensional observer and a PI controller in order to achieve the boundary setpoint regulation control of various system outputs such as the Dirichlet and Neumann traces. In this context, it is shown that the order of the finite-dimensional observer can always be selected large enough, with an explicit criterion, to achieve both the stabilization of the plant and the setpoint regulation of the system output. [ABSTRACT FROM AUTHOR]

Various efforts have been devoted to developing stabilizing distributed model predictive control (MPC) schemes for tracking piecewise constant references. In these schemes, terminal sets are usually computed offline and used in the MPC online phase to guarantee recursive feasibility and asymptotic stability. Maximal invariant terminal sets do not necessarily respect the distributed structure of the network, hindering the distributed implementation of the controller. On the other hand, ellipsoidal terminal sets respect the distributed structure, but may lead to conservative schemes. In this article, a novel distributed MPC scheme is proposed for reference tracking of networked dynamical systems, where the terminal ingredients are reconfigured online depending on the closed-loop states to alleviate the aforementioned issues. The resulting nonconvex infinite-dimensional problem is approximated using a quadratic program. The proposed scheme is tested in simulation, where the proposed MPC problem is solved using distributed optimization. [ABSTRACT FROM AUTHOR]

This article studies global robust output regulation of second-order nonlinear systems with input disturbances that encompass the fully-actuated Euler–Lagrange systems. We assume the availability of relative output (w.r.t. a family of reference signals) and output derivative measurements. Based on a specific separation principle and self-learning mechanism, we develop an internal model-based controller that does not require a priori knowledge of reference and disturbance signals and it only assumes that the kernels of these signals are a family of exosystems with unknown parameters (e.g., amplitudes, frequencies, or time periods). The proposed control framework has a self-learning mechanism that extricates itself from requiring absolute position measurement nor precise knowledge of the feedforward kernel signals. By requiring the high-level task/trajectory planner to use the same class of kernels in constraining the trajectories, the proposed low-level controller is able to learn the desired trajectories, to suppress the disturbance signals, and to adapt itself to the uncertain plant parameters. The framework enables a plug-and-play control mechanism in both levels of control. [ABSTRACT FROM AUTHOR]

In this article, the classical algebraic regulator problem is studied in a data-driven context. The endosystem is assumed to be an unknown system that is interconnected to a known exosystem that generates disturbances and reference signals. The problem is to design a regulator so that the output of the (unknown) endosystem tracks the reference signal, regardless of its initial state and the incoming disturbances. In order to do this, we assume that we have a set of input-state data on a finite time-interval. We introduce the notion of data informativity for regulator design, and establish necessary and sufficient conditions for a given set of data to be informative. Also, formulas for suitable regulators are given in terms of the data. Our results are illustrated by means of two extended examples. [ABSTRACT FROM AUTHOR]

A swarming behavior problem is investigated in this article for heterogeneous uncertain agents with cooperation–competition interactions. In such a problem, the agents are described by second-order continuous systems with different intrinsic nonlinear terms, which satisfies the “linearity-in-parameters” condition, and the agents’ models are coupled together through a distributed protocol containing the information of competitive neighbors. Then, for four different types of cooperation–competition networks, a distributed Lyapunov-based redesign approach is proposed for the heterogeneous uncertain agents, where the distributed controller and the estimation laws of unknown parameters are obtained. Under their joint actions, the heterogeneous uncertain multiagent system can achieve distributed stabilization for structurally unbalanced networks and output bipartite consensus for structurally balanced networks. In particular, the concept of coherent networks is proposed for structurally unbalanced directed networks, which is beneficial to the design of distributed controllers. Finally, four illustrative examples are given to show the effectiveness of the designed distributed controller. [ABSTRACT FROM AUTHOR]

In this article, a data-driven distributed control method is proposed to solve the cooperative optimal output regulation problem of leader–follower multiagent systems. Different from traditional studies on cooperative output regulation, a distributed adaptive internal model is originally developed, which includes a distributed internal model and a distributed observer to estimate the leader’s dynamics. Without relying on the dynamics of multiagent systems, we have proposed two reinforcement learning algorithms, policy iteration and value iteration, to learn the optimal controller through online input and state data, and estimated values of the leader’s state. By combining these methods, we have established a basis for connecting data-distributed control methods with adaptive dynamic programming approaches in general since these are the theoretical foundation from which they are built. [ABSTRACT FROM AUTHOR]

This paper studies the prescribed-time input-to-state stabilization problem of normal nonlinear systems. With the help of some key properties of a class of parametric Lyapunov equations, the prescribed-time input-to-state stabilization problem of normal nonlinear systems under matched uncertainties is studied. Some bounded time-varying controllers are proposed. It is shown that the closed-loop systems are prescribed-time input-to-state stable. Finally, the effectiveness of the established methods is illustrated by two physical systems. [ABSTRACT FROM AUTHOR]

Limitations in communication networks, such as delays, packet dropouts, and insufficient bandwidth, create great challenges in the output tracking control and regulation performance of networked control systems. In this article, we propose some novel performance indexes for achieving the optimal tracking and regulation performance. By considering the influences of noise, packet dropouts, and logarithmic quantization on the channel input, the performance limitations of the networked systems are investigated by applying a two-degree-of-freedom (TDOF) control technique. The results obtained prove that the tracking and regulation performance is dependent not only on the position of the plant’s nonminimum phase zeros and unstable poles, but also on the directions. Furthermore, it is demonstrated that noise and quantization error have a negative influence on the control performance, and the design of the TDOF controller can eliminate the effect of packet dropouts on control performance. To validate the innovation results, several simulations are conducted. [ABSTRACT FROM AUTHOR]

The discrete distributed observer is developed recently to solve the cooperative output regulation problem. The validation of the existing discrete distributed observer depends on the establishment of the communication network. In some practical applications, only the sensor network can be established among all agents. To handle such cases, we propose a sensory feedback-based discrete distributed observer, which depends on the relative output of neighboring agents. In contrast to existing results, the design of the discrete distributed observer and cooperative output regulation analysis should be conducted simultaneously. Resorting to the small-gain theorem, we develop a small-gain condition-based approach and a low-gain-based approach, respectively. By these two approaches, we demonstrate that the discrete distributed observer holds and the cooperative output regulation problem of heterogeneous discrete-time linear multiagent systems can be solved. [ABSTRACT FROM AUTHOR]

Primary-side regulation (PSR) flyback topology with discontinuous conduction modulation (DCM) mode has been widely used in low-power application due to its high stability, wide input voltage range, low cost, and low standby power. To improve the output power, continuous conduction modulation (CCM) mode is always introduced. However, in CCM mode, conventional PSR voltage-sampling method cannot realize high precision of output voltage or the voltage sampling method requires complex control of high cost. In this paper, a simple digital voltage sampling scheme with two reference voltages outputted from a digital-to-analog converter (DAC) is put forward to trace the “accurate-point” voltage for DCM and CCM modes. In CCM mode, the sampling voltage error of the “knee-point” voltage can be compensated just by inserting DCM switching cycle to obtain the “accurate-point” voltage. Voltage difference between DCM mode and CCM mode will be eliminated, and high precision is easily realized. The proposed method is verified in a 20V, 65W PSR flyback converter. The sampling method only requires a low speed DAC, three comparators and a digital controller. The output voltage precision is within 0.6% with universal input voltage. [ABSTRACT FROM AUTHOR]

In this article, we present a novel methodology to address the optimal output consensus problem for multiagent systems. We propose a distributed variable transformation that recasts the aforementioned problem into a simpler regulation problem of the new variables. The transformation requires only relative output measurements and is independent of any underlying agent dynamics and therefore applicable to a general class of systems. Classical control techniques, which take into account the agent dynamics and only need the relative outputs to be shared between neighbors, can then be employed to regulate the new variables. We utilize the methodology to address, for the first time, the problem of optimal output consensus for unknown pure-feedback agents with disturbances and state delays. Simulation studies on a group of continuous stirred tank reactors illustrate the validity of the theoretical analysis. [ABSTRACT FROM AUTHOR]

Although transmission of a data packet containing sensory information in a networked control system improves the quality of regulation, it has indeed a price from the communication perspective. It is, therefore, rational that such a data packet be transmitted only if it is valuable in the sense of a cost-benefit analysis. Yet, the fact is that little is known so far about this valuation of information and its connection with traditional event-triggered communication. In the present article, we study this intrinsic property of networked control systems by formulating a rate-regulation trade-off between the packet rate and the regulation cost with an event trigger and a controller as two distributed decision makers, and show that the valuation of information is conceivable and quantifiable grounded on this trade-off. In particular, we characterize an equilibrium in the rate-regulation trade-off, and quantify the value of information ${\rm{VoI}}_k$ there as the variation in a so-called value function with respect to a piece of sensory information that can be communicated to the controller at each time $k$. We prove that, for a multi-dimensional Gauss--Markov process, ${\rm{VoI}}_k$ is a symmetric function of the discrepancy between the state estimates at the event trigger and the controller, and that a data packet containing sensory information at time $k$ should be transmitted to the controller only if ${\rm{VoI}}_k$ is nonnegative. Moreover, we discuss that ${\rm{VoI}}_k$ can be computed with arbitrary accuracy, and that it can be approximated by a closed-form quadratic function with a performance guarantee. [ABSTRACT FROM AUTHOR]

We introduce the notion of nonoscillation, propose a constructive method for its robust verification, and study its application to biological interaction networks (also known as, chemical reaction networks). We begin by revisiting Muldowney’s result on the nonexistence of periodic solutions based on the study of the variational system of the second additive compound of the Jacobian of a nonlinear system. We show that exponential stability of the latter rules out limit cycles, quasi-periodic solutions, and broad classes of oscillatory behavior. We focus then on nonlinear equations arising in biological interaction networks with general kinetics, and we show that the dynamics of the aforementioned variational system can be embedded in a linear differential inclusion. We then propose algorithms for constructing piecewise linear Lyapunov functions to certify global robust nonoscillatory behavior. Finally, we apply our techniques to study several regulated enzymatic cycles, where available methods are not able to provide any information about their qualitative global behavior. [ABSTRACT FROM AUTHOR]

In this article, we investigate the problem of practical output regulation, i.e., to design a controller that brings the system output in the vicinity of a desired target value while keeping the other variables bounded. We consider uncertain systems that are possibly nonlinear and the uncertainty of their linear parts is modeled element wise through a parametric family of matrix boxes. An optimization-based design procedure is proposed that delivers a continuous-time control and estimates the maximal regulation error. We also analyze an event-triggered emulation of this controller, which can be implemented on a digital platform, along with an explicit estimate of the regulation error. [ABSTRACT FROM AUTHOR]

In this article, we face the reference tracking control problem for a system of heterogeneous multiple unmanned vehicles (MUVs) moving in a 2-D planar environment. We consider a scenario, where each vehicle follows a trajectory imposed by a local planner and where each unmanned vehicle can have different linear dynamics as well as different constraints and disturbances. In this contest, we design a novel control architecture, where a centralized traffic manager, in conjunction with ad-hoc designed local vehicle controllers, is capable of ensuring the absence of collisions. The proposed solution is obtained by exploiting, for the local vehicles’ controllers, a dual-mode model-predictive controller and, for the traffic manager, set-theoretic and controllability properties. Moreover, after modeling the potential vehicle collisions with a graph, connectivity arguments are used to obtain an optimal collision resolution, which minimizes the number of vehicles that need to be stopped. The resulting control scheme ensures collision-free signal tracking. Results of the simulation conducted on an MUV system are shown to provide tangible evidence of the features of the proposed framework. [ABSTRACT FROM AUTHOR]

This article proposes an improved dynamic gain method for studying the global regulation problem of feedforward nonlinear systems. The uncertain nonlinear terms admit an incremental rate depending on an unknown constant and the input. With a transformation of the state, an output feedback controller and a state feedback controller are designed respectively, without resorting to the celebrated forwarding design method. Based on the Lyapunov analysis, it is proved that the global regulation of the closed-loop system is achieved. Different from most existing control constructs for feedforward nonlinear systems, a new time-varying function is used for the first time to design the controller with a dynamic gain, which improves the convergence speed of the system state. Through a simulation example, the advantages of the improved dynamic gain method are illustrated. [ABSTRACT FROM AUTHOR]

Despite pleas for flexibility by infection control groups, the Occupational Safety and Health Administration is being urged by one of its more prominent former directors to adopt a tough standard that emphasizes airborne precautions to protect healthcare workers from COVID-19. [ABSTRACT FROM AUTHOR]

While weak HFC prices dampen refrigerant reclaimer Hudson Technologies' (HDSN) near-term outlook, upcoming regulatory changes could pave the way for a swift and substantial earnings recovery. [ABSTRACT FROM AUTHOR]

Th article explores the topic of conflict resolution. It discusses the nature of conflict and the role of compromise in resolving conflicts. It describes the negative effects of walking away from conflict and the importance of preventing fear and division from spreading. It suggests ways of achieving conflict resolution, such as considering different ideas, listening well to attain cooperation and avoiding judging others.

The reporting requirements will not apply to decentralized finance platforms. [ABSTRACT FROM AUTHOR]

The European Commission has approved the sale of TIM's fixed-line grid to KKR-led consortium. [ABSTRACT FROM AUTHOR]

We present a model predictive control (MPC) framework to solve the constrained nonlinear output regulation problem. The main feature of the proposed framework is that the application does not require the solution to classical regulator (Francis–Byrnes–Isidori) equations or any other offline design procedure. In particular, the proposed formulation simply minimizes the predicted output error, possibly with some input regularization. Instead of using terminal cost/sets or a positive-definite stage cost as is standard in MPC theory, we build on the theoretical results by Grimm et al. using a detectability notion. The proposed formulation is applicable if the constrained nonlinear regulation problem is (strictly) feasible; the plant is incrementally stabilizable and incrementally input–output to state stable (i-IOSS, detectable). We show that for minimum phase systems, such a design ensures exponential stability of the regulator manifold. We also provide a design procedure in case of unstable zero dynamics using an incremental input regularization and a nonresonance condition. The theoretical results are illustrated with an example involving offset-free tracking. [ABSTRACT FROM AUTHOR]

Through the combination of contraction mapping and pseudospectral method, we propose a successive approximation technique to approximate the solution of a class of regulator equations with periodic exosystems and hyperbolic zero dynamics. In this scheme, the initial points of flows on the zero-error constrained manifolds are approximated successively as the fixed point of a contractive integral mapping. Accordingly, flows are obtained by utilizing the scaled Fourier–Gauss–Radau collocation method. Appropriate error analysis, in association with both regulation error and the error resulting from the approximate solution of the center manifold equation, is provided. Our analysis shows that the regulation error becomes negligible as we start the approximation process at an adequately large order and maintain it for a proper number of iterations. [ABSTRACT FROM AUTHOR]

This article deals with the problem of controlling the average state of a large-scale linear network to a constant reference value. We design an output-feedback controller such that no information about state vector or system matrices is needed. For this controller to have arbitrary positive gains, it is sufficient that only a sign condition on system matrices should be satisfied. To assure that the states of the network are close to the average state, the problem of deviation minimization is solved in addition, using a novel extremum seeking algorithm. [ABSTRACT FROM AUTHOR]

We address the output regulation problem for a general class of linear stochastic systems. Specifically, we formulate and solve the ideal full-information and output-feedback problems, obtaining perfect, but noncausal, asymptotic regulation. A characterization of the problem solvability is deduced. We point out that the ideal problems cannot be solved in practice because they unrealistically require that the Brownian motion affecting the system is available for feedback. Drawing from the ideal solution, we formulate and solve approximate versions of the full-information and output-feedback problems, which do not yield perfect asymptotic tracking but can be solved in a realistic scenario. These solutions rely on two key ideas: First, we introduce a discrete-time a posteriori estimator of the variations of the Brownian motion obtained causally by sampling the system state or output; second, we introduce a hybrid state observer and a hybrid regulator scheme which employ the estimated Brownian variations. The approximate solution tends to the ideal as the sampling period tends to zero. The proposed theory is validated by the regulation of a circuit subject to electromagnetic noise. [ABSTRACT FROM AUTHOR]

The Start-up Law appears opportunely in Spain, where the entrepreneurial phenomenon has grown recently. Even so, its support context has developed in a somewhat confused and messy way. Therefore, a structural impulse and ordering of its ecosystem was required, differentiated from the innovation system. The law institutionalizes in a pioneering way a new concept, the Start-up. For this, it is convenient to reinforce the coordination of public and private policies and to have public reference agencies. It makes sense that Enisa is one of them, a key one, due to the experience generated by its loans. Of course, with structure and sufficient resources. [ABSTRACT FROM AUTHOR]

This article revisits the sampled-data cooperative output regulation problem in a hybrid system framework. Due to the inevitable network-induced imperfections caused by communication among agents, we consider the problem under asynchronous transmissions and time-varying delays. A hybrid system model is introduced to incorporate the aforementioned communication imperfections and facilitate the analysis on internal stability and $\mathcal {L}_2$ ($\mathcal {L}_\infty$) performance of closed-loop systems. A novel Lyapunov functional candidate is proposed to establish the stability condition in terms of maximally allowable transmission intervals (MATIs) and maximally allowable delays (MADs). Compared with some existing results, the proposed Lyapunov functional candidate provides clearer physical significance. As a result, more straightforward computations and tradeoff designs on MATIs and MADs can be provided. Finally, numerical simulations are given to illustrate the efficiency and feasibility of the obtained results. [ABSTRACT FROM AUTHOR]

This article studies the robust cooperative output regulation problem of heterogeneous uncertain linear multiagent systems under unbounded distributed transmission delays. A novel distributed observer is first proposed to estimate the state of an exosystem in the presence of unbounded distributed transmission delays. Then, two novel distributed controllers, one based on state feedback and the other based on output feedback, are further developed without any prior knowledge of the unbounded transmission delays. It is shown that the resulting closed-loop multiagent systems can achieve robust cooperative output regulation. It is also shown that the better transient performance is achieved with our proposed controllers in contrast to many existing low-gain controllers, which are proposed to deal with both bounded and unbounded transmission delays. Our results can be directly applied to solve cooperative output regulation problems of multiagent systems with bounded distributed or constant transmission delays. Furthermore, our results can also be directly applied to solve leader–following consensus problems of multiagent systems with unbounded distributed, bounded distributed, or constant transmission delays. Finally, a simulation example is provided to illustrate the effectiveness of the proposed controllers. [ABSTRACT FROM AUTHOR]

In this article, we consider robust output tracking for a Schrödinger equation with external disturbances in all possible channels. The challenge of the problem comes from the fact that the observation operator is unbounded and the regulated output and the control are noncollocated. An observer-based approach is adopted in investigation. We first select specially some coefficients of the disturbances to obtain a nominal system, which is a coupled PDE+ODE system. For this nominal system, we design a feedforward control by solving related regulator equation. An observer is then designed for the nominal system in terms of the tracking error only. As a result, an error feedback control is, thus, designed by replacing the state and disturbances in the feedforward control with their estimates obtained from the observer. We show that this observer based error feedback control is robust to disturbances in all possible channels and system uncertainty. The stability of the closed loop and convergence are established by the Riesz basis approach. Some numerical simulations are presented to validate the results. [ABSTRACT FROM AUTHOR]

The objective of the article is first to show there are worrying signs that the consensus about independent regulation is cracking in several countries that matter. We then go on to demonstrate that there are blind spots in the European framework of public service regulation. Regulation in the EU focuses too much on competition and not enough on other objectives. Finally we attempt to rethink the regulatory framework of public services in Europe in a way that would take all the competing interests of society into account. Although the main focus of the article falls on French and European experiences, it also adopts a broader view. [ABSTRACT FROM AUTHOR]

This article considers the robust cooperative output regulation for a network of parabolic PDE systems. The solution to this problem is obtained by extending the cooperative internal model principle from finite to infinite dimensions. For a time-invariant digraph describing the communication topology, a two-step backstepping approach is presented to systematically design cooperative state feedback regulators. This allows to solve both the leader–follower and the leaderless output synchronization problem in the presence of disturbances and model uncertainty for a finite-dimensional leader. Solvability conditions of the robust cooperative output regulation problem are presented in terms of the communication graph and the agent transfer behavior. The results of this article are demonstrated for a network consisting of four uncertain parabolic agents with and without a finite-dimensional leader in the presence of disturbances. [ABSTRACT FROM AUTHOR]

In this article, we examine a regulator problem for a class of fully actuated continuous-time invariant systems on Lie groups, using a discrete-time controller with constant sampling period. We present a smooth discrete-time control law that achieves global regulation on simply connected nilpotent Lie groups. We first solve the problem when both the plant state and exosystem state are available for feedback, then in the case where the plant state and plant output are available for feedback. The class of plant outputs considered includes, for example, the quantity to be regulated. This class of outputs allows us to use the classical Luenberger observer to estimate the exosystem states. In the full-information case, the regulation quantity on the Lie algebra is shown to decay exponentially to zero, which implies that it tends asymptotically to the identity on the Lie group. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin de l'Académie Vétérinaire de France is the property of Academie Veterinaire de France and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article studies robust output tracking and disturbance rejection for boundary-controlled infinite-dimensional Port–Hamiltonian systems including second-order models such as the Euler–Bernoulli beam equation. The control design is achieved using the internal model principle and the stability analysis using a Lyapunov approach. Contrary to existing works on the same topic, no assumption is made on the external well-posedness of the considered class of PDEs. The results are applied to robust tracking of a piezo actuated tube used in atomic force imaging. [ABSTRACT FROM AUTHOR]

This article presents a visual navigation and landing control paradigm for an unmanned aerial vehicle (UAV) to land on a moving autonomous surface vehicle (ASV). Therein, an adaptive learning navigation rule with a multilayer nested guidance is designed to pinpoint the position of the ASV and to guide and control the UAV to fulfill horizontal tracking and vertical descending in a narrow landing region of the ASV by means of merely relative position feedback. To ensure the feasibility of the proposed control law, asymptotical stability conditions are derived based on Lyapunov stability theory. Landing experimental results are reported for a UAV-ASV system consisting of an M-100 UAV and a self-developed three-meters-long HUSTER-30 ASV on a lake to substantiate the efficacy of the proposed landing control method. [ABSTRACT FROM AUTHOR]

In this article, we address a problem of output regulation for a broad class of invertible multi-input–multi-output (MIMO) nonlinear systems. The system that we consider is assumed to possess a globally defined normal form, in which appropriate invertibility conditions are fulfilled, and to be strongly minimum phase. Asymptotic output regulation is achieved by means of a controller consisting of a preprocessing internal model and of a robust stabilizer. For the design of the latter, a recently developed method is proposed, consisting of interlaced design of dynamic extensions and extended observers that provides a robust version of standard stabilization methods based on feedback-linearization. The method does not presume the knowledge of an accurate model of the plant and only needs access to the regulated variables. [ABSTRACT FROM AUTHOR]

An output robust adaptive control is designed for a class of Lipschitz nonlinear systems under assumption that the measurements are available with a constant bias and the state equations linearly parameterized by unknown parameters and external disturbances. A dynamic state reconstruction (synthesis of an observer) is avoided by using delayed values of the output in the feedback and adaptation laws. The analysis of robust stability for the resulted time-delay system is performed by using the Lyapunov–Krasovskii approach. The control and adaptation gains can be selected as a solution of the proposed linear matrix inequalities. This research is motivated by a nonlinear pendulum control problem, and the efficacy of the developed control is demonstrated on this application through experiments. [ABSTRACT FROM AUTHOR]