Synthesis for Constrained Nonlinear Systems using Hybridization and Robust Controllers on Simplices

In this paper, we propose an approach to controller synthesis for a class of constrained nonlinear systems. It is based on the use of a hybridization, that is a hybrid abstraction of the nonlinear dynamics. This abstraction is defined on a triangulation of the state-space where on each simplex of the triangulation, the nonlinear dynamics is conservatively approximated by an affine system subject to disturbances. Except for the disturbances, this hybridization can be seen as a piecewise affine hybrid system on simplices for which appealing control synthesis techniques have been developed in the past decade. We extend these techniques to handle systems subject to disturbances by synthesizing and coordinating local robust affine controllers defined on the simplices of the triangulation. We show that the resulting hybrid controller can be used to control successfully the original constrained nonlinear system. Our approach, though conservative, can be fully automated and is computationally tractable. To show its effectiveness in practical applications, we apply our method to control a pendulum mounted on a cart

Continuous-time consensus under persistent connectivity and slow divergence of reciprocal interaction weights

In this paper, we present new results on consensus for continuous-time multi- agent systems. We introduce the assumptions of persistent connectivity of the interaction graph and of slow divergence of reciprocal interaction weights. Persistent connectivity can be considered as the counterpart of the notion of ultimate connectivity used in discrete- time consensus protocols. Slow divergence of reciprocal interaction weights generalizes the assumption of cut-balanced interactions. We show that under these two assumptions, the continuous-time consensus protocol succeeds: the states of all the agents converge asymptotically to a common value. Moreover, our proof allows us to give an estimate of the rate of convergence towards the consensus. We also provide two examples that make us think that both of our assumptions are tight

Le territoire, « matrice » de culture : Analyse des mémoires déposés à la commission Coulombe par les premières nations du Québec

Cet article présente une analyse des mémoires déposés par les premières nations du Québec à la Commission d’étude sur la gestion de la forêt publique québécoise (2004). Les mémoires et les présentations révèlent une pluralité d’approches au sein des communautés autochtones et entre elles. Cependant, par delà cette pluralité on peut déceler une vision commune de la forêt qui est érigée en matrice de civilisation, comme l’avaient été lors de la crise hydroélectrique des années 1975-1980 les lacs et les rivières. Ce changement d’ancrage physique de la culture – de l’eau vers la forêt – s’accompagne d’une nouvelle attitude face aux autres acteurs du développement, notamment l’État et l’industrie. En effet, face aux développements forestiers, les premières nations du Québec demandent une plus grande autonomie et le respect de leurs droits ancestraux mais elles ne réclament plus systématiquement l’arrêt du développement industriel de leur territoire, demandant plutôt à être intégrées de plein droit dans la gouvernance de celui-ci.In this article we present an analysis of the briefs submitted by Québec’s First Nations at the Commission for the study of public forest management in Québec (2004). The briefs and presentations made by them reveal the multiplicity of approaches within and between First Nations. However, beyond this multiplicity we can detect a common vision of the forest which is erected as a civilisation matrix, as were the lakes and rivers at the time of the hydroelectric crisis in 1975-1980. This change in the culture’s physical anchorage – from water to forest – is accompanied by a new attitude towards other development actors, notably the State and the industry. Indeed, in the face of forest development, Québec’s First Nations ask for a greater autonomy and the respect of their ancestral rights, but they do not systematically demand the halt of their territory’s industrial development, but rather ask to be rightfully integrated in its governance

Probing Terahertz Metamaterials with Subwavelength Optical Fibers

Transmission through a subwavelength terahertz fiber, which is positioned in parallel to a frequency selective surface, is studied using several finite element tools. Both the band diagram technique and the port-based scattering matrix technique are used to explain the nature of various resonances in the fiber transmission spectrum. First, we observe that spectral positions of most of the transmission peaks in the port-based simulation can be related to the positions of Van Hove singularities in the band diagram of a corresponding infinite periodic system. Moreover, spectral shape of most of the features in the fiber transmission spectrum can be explained by superposition of several Fano-type resonances. We also show that center frequencies and bandwidths of these resonances and, as a consequence, spectral shape of the resulting transmission features can be tuned by varying the fiber-metamaterial separation

Trajectories of mental health problems in childhood and adult voting behaviour:Evidence from the 1970s British Cohort Study

The link between childhood mental health difficulties such as conduct problems and adult political abstention has been overlooked despite early mental health difficulties potentially resulting in political self-marginalisation. Using the1970s British Cohort Study, we estimate developmental trajectories of conduct problems (i.e., from 5 to 16 years). Logistic regression, linear probability models, and propensity score matching were then conducted to test the association between trajectory group membership and voter turnout at 30, 42, and 46 years of age. Three distinct trajectories of conduct problems were identified: a normative (n = 11,871; reference group), moderate-chronic (n = 3433), and elevated-chronic (n = 250) group. Results revealed an association between conduct problems and decreased turnout. In particular the elevated-chronic group had a decreased odds of voting of 52.2%, 52.0%, and 45.7%, as compared to the normative group at 30, 42, and 46 years respectively. The moderate-chronic group had a decreased odds of voting of 24.7% as compared to the normative group at age 30 only. Matched results and linear probability models substantiated findings, suggesting (1) the importance of considering childhood factors when examining antecedents of lifelong voting behaviour, and (2) the political self-marginalisation of people with chronic childhood conduct problems more than 3 decades later. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11109-022-09852-9

Trajectories of Mental Health Problems in Childhood and Adult Voting Behaviour: Evidence from the 1970s British Cohort Study

The link between childhood mental health difficulties such as conduct problems and adult political abstention has been overlooked despite early mental health difficulties potentially resulting in political self-marginalisation. Using the1970s British Cohort Study, we estimate developmental trajectories of conduct problems (i.e., from 5 to 16 years). Logistic regression, linear probability models, and propensity score matching were then conducted to test the association between trajectory group membership and voter turnout at 30, 42, and 46 years of age. Three distinct trajectories of conduct problems were identified: a normative (n = 11,871; reference group), moderate-chronic (n = 3433), and elevated-chronic (n = 250) group. Results revealed an association between conduct problems and decreased turnout. In particular the elevated-chronic group had a decreased odds of voting of 52.2%, 52.0%, and 45.7%, as compared to the normative group at 30, 42, and 46 years respectively. The moderate-chronic group had a decreased odds of voting of 24.7% as compared to the normative group at age 30 only. Matched results and linear probability models substantiated findings, suggesting (1) the importance of considering childhood factors when examining antecedents of lifelong voting behaviour, and (2) the political self-marginalisation of people with chronic childhood conduct problems more than 3 decades later.publishedVersio

Coordination in networks of linear impulsive agents

International audienceThe paper focuses on consensus in heterogeneous networks containing both linear and linear impulsive dynamics. This model applies for networks that are formed by several clusters. Most agents can only update their state in a continuous way using inner-cluster agent states. On top of this, few agents also have the peculiarity to update their states in a discrete way by reseting it using states from agents outside their clusters. The motivation of this behavior is that communication constraints hamper continuous inter-clusters interactions. Under appropriate assumptions we prove that all subsystems asymptotically agree and we provide an upper-bound of the convergence speed. We illustrate the behavior with an academic example containing five agents grouped in two clusters

Inductive-data-type Systems

In a previous work ("Abstract Data Type Systems", TCS 173(2), 1997), the last two authors presented a combined language made of a (strongly normalizing) algebraic rewrite system and a typed lambda-calculus enriched by pattern-matching definitions following a certain format, called the "General Schema", which generalizes the usual recursor definitions for natural numbers and similar "basic inductive types". This combined language was shown to be strongly normalizing. The purpose of this paper is to reformulate and extend the General Schema in order to make it easily extensible, to capture a more general class of inductive types, called "strictly positive", and to ease the strong normalization proof of the resulting system. This result provides a computation model for the combination of an algebraic specification language based on abstract data types and of a strongly typed functional language with strictly positive inductive types.Comment: Theoretical Computer Science (2002

Identification of radiation induced dark current sources in pinned photodiode CMOS image sensors

This paper presents an investigation of Total Ionizing Dose induced dark current sources in Pinned PhotoDiodes (PPD) CMOS Image Sensors based on pixel design variations. The influence of several layout parameters is studied. Only one parameter is changed at a time enabling the direct evaluation of its contribution to the observed device degradation. By this approach, the origin of radiation induced dark current in PPD is localized on the pixel layout. The PPD peripheral STI does not seem to play a role in the degradation. The PPD area and an additional contribution independent on the pixel dimensions appear to be the main sources of the TID induced dark current increase