Search results for "DISTURBANCE"
showing 10 items of 232 documents
The effects of long-term drainage and subsequent restoration on water table level and pore water chemistry in boreal peatlands
2014
Summary Degradation by drainage threatens biodiversity and globally important peatland ecosystem functions such as long-term carbon sequestration in peat. Restoration aims at safeguarding peatland values by recovering natural hydrology. Long-term effects of drainage and subsequent restoration, especially related to within-site variation of water table level and pore water chemistry, are poorly known. We studied hydrological variation at 38 boreal Sphagnum peatland sites (pristine, drained and restored) in Finland. The average water table level was significantly lower at Drained than Pristine sites especially near the ditches. We also observed large pore water chemical differences between Dr…
ROBUST CONTROL STRATEGIES FOR MULTI—INVENTORY SYSTEMS WITH AVERAGE FLOW CONSTRAINTS
2006
Abstract In this paper we consider multi—inventory systems in presence of uncertain demand. We assume that i) demand is unknown but bounded in an assigned compact set and ii) the control inputs (controlled flows) are subject to assigned constraints. Given a long—term average demand, we select a nominal flow that feeds such a demand. In this context, we are interested in a control strategy that meets at each time all possible current demands and achieves the nominal flow in the average. We provide necessary and sufficient conditions for such a strategy to exist and we characterize the set of achievable flows. Such conditions are based on linear programming and thus they are constructive. In …
Description of the Interim Peculiarities of Mental Developmental and Learning Disturbances
2015
More and more pupils with special needs, including those with learning disturbances and simple mental developmental disturbances, are attending general comprehensive educational institution. It is often difficult in practice to define clearly and differentiate these two kinds of disturbances, especially in borderline cases or in the interim stage because then the features and manifestations of learning disturbances and simple mental developmental disturbances partly overlap and change. The novelty of the article is the analysis of the interim peculiarities and manifestations of these two disturbances which will allow teachers to understand better the main learning difficulties of such pupil…
Observer-based H∞ control on stochastic nonlinear systems with time-delay and actuator nonlinearity
2013
Abstract In this paper, an observer-based H ∞ controller is designed for a class of extended Markov jump systems subject to time-delay and actuator saturation nonlinearity. Gradient linearization procedure is employed to describe such nonlinear systems by several linear Markov jump systems. Next, a mode-dependent Lyapunov function is constructed for these linear systems, and a sufficient condition is derived to make them stochastically stable, and then, a continuous gain-scheduled approach is applied to design a continuous nonlinear observer-based controller on the entire extended nonlinear jump system. A simulation example is given to illustrate the effectiveness of developed techniques.
Robust H∞ synchronization of a hyper-chaotic system with disturbance input
2013
Abstract This paper concerns the robust control problems on the synchronization of a hyper-chaotic system with disturbance input. Using an appropriate Lyapunov function, we design the multi-dimensional and the single-dimensional robust H ∞ synchronization controllers in terms of linear matrix inequalities for the application in practical engineering. Corresponding theoretical derivations are given subsequently. Finally, some numerical simulations are provided to demonstrate the effectiveness of the proposed techniques.
-Infinity robust controller design for the synchronization of master-slave chaotic systems with disturbance input
2012
Published version of an article from the journal: Modeling, Identification and Control. Also available from the publisher: http://dx.doi.org/10.4173/mic.2012.1.3 This paper is concerned with the robust control problems for the synchronization of master-slave chaotic systems with disturbance input. By constructing a series of Lyapunov functions, novel H1 robust syn- chronization controllers are designed, whose control regulation possess the characteristic of simpleness and explicitness. Finally, numerical simulations are provided to demonstrate the e ectiveness of the proposed techniques.
Disturbance tolerance and rejection of discrete switched systems with time-varying delay and saturating actuator
2015
Abstract This paper is concerned with the problems of disturbance tolerance and rejection of discrete switched systems with time-varying delay and saturating actuator. Using the switched Lyapunov function approach, a sufficient condition for the existence of a state feedback controller is proposed such that the disturbance tolerance capability of the closed-loop system is ensured. By solving a convex optimization problem with linear matrix inequality (LMI) constraints, the maximal disturbance tolerance is estimated. In addition, the problem of disturbance rejection of the closed-loop system is solved. Two examples are given to illustrate the effectiveness of the proposed method.
A field test of behavioural flexibility in Zenaida doves (Zenaida aurita).
2010
7 pages; International audience; Animals' ability to adjust their behaviour when environmental conditions change can increase their likelihood of survival. Although such behavioural flexibility is regularly observed in the field, it has proven difficult to systematically quantify and predict inter-individual differences in free-living animals. We presented 24 Zenaida doves (Zenaida aurita) on 12 territories with two learning tests in their natural habitat in Barbados. The dove pairs showed high site fidelity and territoriality, allowing us to test individuals repeatedly while accounting for the effects of territorial chases and pair bonds on our learning measures. We used a foraging apparat…
Gut microbiota disturbance during antibiotic therapy: a multi-omic approach
2014
It is known that the gastrointestinal tract (GIT) microbiota responds to different antibiotics in different ways and that while some antibiotics do not induce disturbances of the community, others drastically influence the richness, diversity, and prevalence of bacterial taxa. However, the metabolic consequences thereof, independent of the degree of the community shifts, are not clearly understood. In a recent article, we used an integrative OMICS approach to provide new insights into the metabolic shifts caused by antibiotic disturbance. The study presented here further suggests that specific bacterial lineage blooms occurring at defined stages of antibiotic intervention are mostly associa…
Loss-of-function maternal-effect mutations of PADI6 are associated with familial and sporadic Beckwith-Wiedemann syndrome with multi-locus imprinting…
2020
Abstract Background PADI6 is a component of the subcortical maternal complex, a group of proteins that is abundantly expressed in the oocyte cytoplasm, but is required for the correct development of early embryo. Maternal-effect variants of the subcortical maternal complex proteins are associated with heterogeneous diseases, including female infertility, hydatidiform mole, and imprinting disorders with multi-locus imprinting disturbance. While the involvement of PADI6 in infertility is well demonstrated, its role in imprinting disorders is less well established. Results We have identified by whole-exome sequencing analysis four cases of Beckwith-Wiedemann syndrome with multi-locus imprintin…