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State Transformation (state + transformation)

Distribution by Scientific Domains

Engineering	50%
Life Sciences	30%

Selected Abstracts

Robust tracking control for a class of MIMO nonlinear systems with measurable output feedback

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2008
Ya-Jun Pan
Abstract This paper proposes a robust output feedback controller for a class of nonlinear systems to track a desired trajectory. Our main goal is to ensure the global input-to-state stability (ISS) property of the tracking error nonlinear dynamics with respect to the unknown structural system uncertainties and external disturbances. Our approach consists of constructing a nonlinear observer to reconstruct the unavailable states, and then designing a discontinuous controller using a back-stepping like design procedure to ensure the ISS property. The observer design is realized through state transformation and there is only one parameter to be determined. Through solving a Hamilton,Jacoby inequality, the nonlinear control law for the first subsystem specifies a nonlinear switching surface. By virtue of nonlinear control for the first subsystem, the resulting sliding manifold in the sliding phase possesses the desired ISS property and to certain extent the optimality. Associated with the new switching surface, the sliding mode control is applied to the second subsystem to accomplish the tracking task. As a result, the tracking error is bounded and the ISS property of the whole system can be ensured while the internal stability is also achieved. Finally, an example is presented to show the effectiveness of the proposed scheme. Copyright © 2007 John Wiley & Sons, Ltd. [source]

An algorithm for the structural analysis of state space: synthesis of nonlinear observers

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2001
Virgilio López-Moralès
Abstract The problem addressed is the linearization of multi-input multi-output (MIMO) nonlinear systems by a generalized state coordinates transformation and generalized input,output injection, in order to design an observer. This observer will have linear error dynamics. The goal is to bring together two observers design approaches: a structural one and a numerical one. Necessary and sufficient conditions for the existence of a linearizing generalized state transformation are obtained by an algebraic way and without computing the input,output differential equations. The main result tests integrability conditions of differential one-forms derived from the state space representation and is applicable to a large subclass of nonlinear systems. Copyright © 2001 John Wiley & Sons, Ltd. [source]

A Multi-phase-field model including inelastic deformation for solid state transformations

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008
Stefan BenkeArticle first published online: 26 FEB 200
A multi phase field model is presented in order to take the plastic deformation during a solid state transformation into account and to investigate its effect on the transformation kinetics and morphology in a multi phase material. The model is formulated consistently with the multi phase field model for diffusional and surface driven phase transformations [1]. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A NEW DESIGN APPROACH TO DELAY-DEPENDENT ROBUST H, CONTROL FOR UNCERTAIN TIME-DELAY SYSTEMS

ASIAN JOURNAL OF CONTROL, Issue 4 2004
Ning-Jun Su
ABSTRACT A new design approach to delay-dependent robust stabilization and robust H, control for a class of uncertain time-delay systems is provided in this paper. The sufficient conditions for delay-dependent robust stabilization and robust H, control are derived based on a new state transformation and given in terms of linear matrix inequalities (LMI). Numerical examples are presented to show that the proposed results can be less conservative and can be used to deal with not only small but also large delay systems. [source]

Multiple-Element Matching Reservoir Formation and Quantitative Prediction of Favorable Areas in Superimposed Basins

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2010
WANG Huaijie
Abstract: Superimposed basins in West China have experienced multi-stage tectonic events and multicycle hydrocarbon reservoir formation, and complex hydrocarbon reservoirs have been discovered widely in basins of this kind. Most of the complex hydrocarbon reservoirs are characterized by relocation, scale re-construction, component variation and phase state transformation, and their distributions are very difficult to predict. Research shows that regional caprock (C), high-quality sedimentary facies (Deposits, D), paleohighs (Mountain, M) and source rock (S) are four geologic elements contributing to complex hydrocarbon reservoir formation and distribution of western superimposed basins. Longitudinal sequential combinations of the four elements control the strata of hydrocarbon reservoir formation, and planar superimpositions and combinations control the range of hydrocarbon reservoir and their simultaneous joint effects in geohistory determine the time of hydrocarbon reservoir formation. Multiple-element matching reservoir formation presents a basic mode of reservoir formation in superimposed basins, and we recommend it is expressed as T-CDMS. Based on the multiple-element matching reservoir formation mode, a comprehensive reservoir formation index (Tcdms) is developed in this paper to characterize reservoir formation conditions, and a method is presented to predict reservoir formation range and probability of occurrence in superimposed basins. Through application of new theory, methods and technology, the favorable reservoir formation range and probability of occurrence in the Ordovician target zone in Tarim Basin in four different reservoir formation periods are predicted. Results show that central Tarim, Yinmaili and Lunnan are the three most favorable regions where Ordovician oil and gas fields may have formed. The coincidence of prediction results with currently discovered hydrocarbon reservoirs reaches 97%. This reflects the effectiveness and reliability of the new theory, methods and technology. [source]

Parallel evolution of larval morphology and habitat in the snail-killing fly genus Tetanocera

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2006
E. G. CHAPMAN
Abstract In this study, we sequenced one nuclear and three mitochondrial DNA loci to construct a robust estimate of phylogeny for all available species of Tetanocera. Character optimizations suggested that aquatic habitat was the ancestral condition for Tetanocera larvae, and that there were at least three parallel transitions to terrestrial habitat, with one reversal. Maximum likelihood analyses of character state transformations showed significant correlations between habitat transitions and changes in four larval morphological characteristics (cuticular pigmentation and three characters associated with the posterior spiracular disc). We provide evidence that phylogenetic niche conservatism has been responsible for the maintenance of aquatic-associated larval morphological character states, and that concerted convergence and/or gene linkage was responsible for parallel morphological changes that were derived in conjunction with habitat transitions. These habitat,morphology associations were consistent with the action of natural selection in facilitating the morphological changes that occurred during parallel aquatic to terrestrial habitat transitions in Tetanocera. [source]

Rapid and convergent evolution of parental care in hydrobiid gastropods from New Zealand

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2005
M. HAASE
Abstract Although parental care occurs in most phyla encompassing a wide array of forms, little is known about its evolution in invertebrates. Two types of egg capsules have been known among ovoviviparous New Zealand hydrobiid gastropods, elastic capsules and simple membranes. Based on a phylogenetic analysis using two mtDNA sequence fragments, I asked whether the second state was derived from the first or whether brooding had multiple origins. The evolution of ovoviviparity was also investigated in the context of habitat transition between brackish and freshwater. Maximum parsimony and Markov chain models of character state transformations in a maximum likelihood framework suggested that hydrobiids have invaded freshwater three times independently. Two of these invasions were followed by the evolution of ovoviviparity, probably in adaptation to changing water levels during periods of irregular precipitation. The syntopy of two congeneric species, one oviparous and the other one brooding, indicated that the transition between reproductive modes must have occurred rapidly. [source]

A Multi-phase-field model including inelastic deformation for solid state transformations

Analysing the history of the derelomine flower weevil,Carludovica association (Coleoptera: Curculionidae; Cyclanthaceae)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2004
NICO M. FRANZ
The evolutionary history of the interaction among species of derelomine flower weevils (Coleoptera: Curculionidae: Derelomini) and the Panama-hat palm Carludovica (Cyclanthaceae) is analysed with emphasis on the congruence of (1) topologies and (2) character state transformations in each of the Neotropical clades. For this purpose cladistic analyses are complemented with host plant records, natural history information and selected morphological studies of the associated taxa. The interaction is specialized, involving pollination, oviposition into the inflorescences and the predation of seeds (particularly within Systenotelus). As results from a range of standard coevolutionary methods of analysis indicate, however, events of colonization, extinction and independent (non-reciprocal) speciation have been abundant throughout the history of the association. At the same time it is possible to specify the homology and succession of characters among species of derelomines and Carludovica and interpret them as reciprocal adaptations to attack and protect the seeds, respectively. It is argued that , in light of the limited evolutionary stability of many insect,plant interactions , the question of coevolution is most effectively addressed by combining information from the character- and topology-based approaches. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81, 483,517. [source]

Modeling Relations in Nature and Eco-Informatics: A Practical Application of Rosennean Complexity

CHEMISTRY & BIODIVERSITY, Issue 10 2007

Abstract The purpose of eco-informatics is to communicate critical information about organisms and ecosystems. To accomplish this, it must reflect the complexity of natural systems. Present information systems are designed around mechanistic concepts that do not capture complexity. Robert Rosen's relational theory offers a way of representing complexity in terms of information entailments that are part of an ontologically implicit ,modeling relation'. This relation has corresponding epistemological components that can be captured empirically, the components being structure (associated with model encoding) and function (associated with model decoding). Relational complexity, thus, provides a long-awaited theoretical underpinning for these concepts that ecology has found indispensable. Structural information pertains to the material organization of a system, which can be represented by data. Functional information specifies potential change, which can be inferred from experiment and represented as models or descriptions of state transformations. Contextual dependency (of structure or function) implies meaning. Biological functions imply internalized or system-dependent laws. Complexity can be represented epistemologically by relating structure and function in two different ways. One expresses the phenomenal relation that exists in any present or past instance, and the other draws the ontology of a system into the empirical world in terms of multiple potentials subject to natural forms of selection and optimality. These act as system attractors. Implementing these components and their theoretical relations in an informatics system will provide more-complete ecological informatics than is possible from a strictly mechanistic point of view. This approach will enable many new possibilities for supporting science and decision making. [source]