170,569 research outputs found
Niadenie nelinearnych systemov: Algebricky pristup
No full texttraduzione in slovacco del volume:
Nonlinear Control Systems, An algebraic setting, G. Conte, C.H. Moog and A.M. Perdon, Springer Lecture Notes in Control and Information Science, Springer vol. 242, (March 1999) ISBN 1-85233-151-
T-Accessibility for a class of nonlinear time–delay systems
No full textObservability and detectability on one hand as well as accessibility and controllability on the other, are related properties and have not been closely investigated for nonlinear–time delay systems until these recent years. Currently accessibility or nonlinear time delay systems is defined as the absence of autonomous functions on the extended state space. Such a property is expressed in terms of the Accessibility matrix rank, extending to the nonlinear context the well known Kalman Criterion. A weaker notion is introduced in this paper which is motivated by the fact that even if autonomous functions exist for the given system, it may be still possible to move from a fixed point to an arbitrary one in some open subset of IRn. The study is performed on the class of driftless single input system
Feedback linearization of nonlinear time-delay systems over a time window via discontinuous control
No full textFeedback linearization is worked out for nonlinear time-delay systems and it is shown that even if the problem can not be solved for all time, it may still be solved over some time windows. The solution then reduces to a discontinuous state feedback. It is foreseen that such piecewise feedback linearization can be instrumental for stabilization by a discontinuous control, although it is not the scope of this paper. The approach used herein may be used to address other classical control problems. It takes advantage of the delays as delays duplicate somehow the number of independent control values at some given time instant
Observability of nonlinear time–delay systems and its application to their state realization
No full textIn this paper, it is shown that the two notions of weak observability and strong observability may not be sufficient to describe the link between the input/output equation associated to the behaviour of a system and its state space realization. A new notion, called regular observability, is introduced, which is shown to capture essential features of nonlinear time delay systems and the existence of some realization
On the chained form with delays on the state variables
No full textThe chained form with time-delays on the state variables is introduced. It generalizes the classical chained form which is encountered in mobile robotics with non holonomic constraints. In the present paper necessary and sufficient conditions are given for the equivalence to the considered form under bicausal change of coordinates. Peculiarities of time delay systems are highlighted
Diabetic Gastroparesis Modeling and Observer Design
No full textType 1 diabetes results from the lack of endogenous production of insulin by the pancreas.
According to various references, 4% to 12% of diabetic patients are affected by gastroparesis which
delays the digestion process. Gastroparesis is characterized by a constellation of gastrointestinal
symptoms in association with delayed gastric emptying (GE). For the first time, a mathematical model
is introduced to describe the glycemia dynamics for this significant class of patients. It is shown to yield
to a nonlinear time delay model designed for estimation and control
Decomposition and equivalence of general nonlinear dynamical control systems
No full textProjection and equivalence concepts havebeen widely studied in the literature. In the presentpaper two nonlinear systems with the same numberof inputs, but not the same number of state variables,are considered. Under mild assumptions, necessary andsufficient conditions are given for the existence of asubmersion such that the higher dimensional systemprojects locally onto the other one. The solution tothis problem has relevant applications, for instance inrobotics. It includes as a special case the equivalenceof nonlinear systems with no particular structure
Aen de Hoogh. Moog. Heeren Staten Generael der Vereenighde Nederlanden.
No full textAdres van de participanten der West-Indische Compagnie, zonder dagteken. en afzond. titelVingerafdruk: 000004 - b1 A en : b2 C dsExtract uyt het register der resolutien van haer Hoogh Moog den xix. January 1649Verpakt met de steun van Fonds Inbev-Latour (2010-2012)Herkomst: Vignet Isaac MeulmanVan der Wulp, J. K. Tractaten, pamfletten enz. ; 4523Europeana-GoogleBook
Mixed forests reconsidered: A forest economics contribution on an ecological concept
No full textTo stimulate an economically oriented discussion on mixed forest management, this paper considers economic implications of mixed investments of pure stands of the Norway spruce (Picea abies (L.) Karst.) and the European beech (Fagus sylvatica L.) on a methodological basis. It is well known that the classical economic calculus leads to an overwhelming financial superiority of single species coniferous forest management in Central Europe, especially for growing monocultures of spruce. This explains why, since the early 19th century, the range of these forest types extends far beyond their natural limits. The change in the natural vegetation cover bore severe environmental problems as it was accompanied by a loss of biodiversity and a severe reduction in the resistance against storm, snow, ice, drought and insect damage of the forest stands. In contrast to this development as early as 1886, the Bavarian silviculturist Karl Gayer claimed that the forest condition must be able to deal with the uncertainty of future development. While pointing out that this condition could only be provided by “mixed forests” he, as a pioneer, formed an ecological concept for forest management. Unfortunately, forest managers have not broadly accepted his concept up to now. In order to support the ecological idea of “mixed forests”, it seems crucial to demonstrate that mixed diverse forests also possess economic advantages. Through using the portfolio theory founded by Markowitz and Sharpe, this paper evaluates mixed forest management and compares it to single species forest management. Its focus is on mixtures of Norway spruce and European beech. The Monte Carlo simulation method was used to simulate expected financial returns and their dispersion under risk. Mixed forests reduce the profitability but also show diversification effects due to only weak positive or even slightly negative correlated timber markets and diversified time structure of the timber harvests. Risk-averse decision-makers should therefore establish ecologically desired mixed forests with beech proportions between 10% and 50%, even if the profitability for mixed forests decreases. They will however benefit largely due to a significant risk attenuation. Although, effects of small-scale mixtures in stands comprising of many species were not considered we are sure that the findings of this study will in part also apply to mixtures on the forest stand level. While analysing an ecological concept from an economic viewpoint, which is transferable to the general idea of natural diversity, we intend to arouse interest in the ecologically oriented reader to evoke intensified future cooperation
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