bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model reference adaptive control with unknown relative degree
Authors: Moctezuma Rubén G. , Lozano Rogelio , Suárez Dionisio A. 
Published: July 2007

AbstractThis work presents an indirect, model reference adaptive control for minimum phase linear systems of arbitrary relative degree. Global stability of the closed‐loop system is proved in spite of bounded disturbances and asympotic tracking is achieved in the ideal case.
A self‐organizing knn fuzzy controller and its neural network structure
Authors: Kwon T. M. , Zervakis M. E. 
Published: July 2007

AbstractThis paper introduces a fuzzy controller that can be designed without specific information on the membership functions and the fuzzy rules. We show how the membership values of crisp inputs can be determined by K‐nearest‐neighbour (KNN) distance measures applied to the centres of the input clusters. Based on this new type of membership values, we introduce a KNN defuzzification method that allows the direct estimation of the crisp output of the given input data. the proposed computational model requires a clustering (self‐organizing) process. We employ a simple clustering method that can adaptively allocate new clusters as more data become available to the controller. We prove that the resulting controller can uniformly approximate any real and continuous function to any desirable accuracy on a compact set. For hardware implementations we develop a neural network structure of the proposed fuzzy controller and compare it with other types of neural networks. It is shown that the three‐layer sigmoid neural network and the Gaussian radial basis function (GRBF) network are special cases of this structure. A learning algorithm for the new structure is provided. the performance of the proposed controller is considered through three application studies: a controller design for truck backer‐upper control, the prediction of the S&P 500 index, and the prediction of the Mackey‐Glass time series.
Adaptive estimation for periodic signal enhancement and tracking
Authors: Händel Peter , Tichavský Petr 
Published: July 2007

AbstractA fast algorithm for enhancement and tracking of periodic signals with fixed or slowly varying central frequency in additive noise is proposed. the algorithm is based on results from discounted least squares identification of a harmonic signal model combined with a recursive update scheme for the estimated fundamental frequency. In particular the gain sequence of the algorithm is determined by the fundamental frequency and an eligible forgetting factor. the performance of the algorithm is compared with theoretical lower bounds and it is shown that the algorithm yields good results.
An adaptive filter using scanning observation with application to a DPS
Authors: Muraca P. , Pugliese P. 
Published: July 2007

AbstractIn this paper an observation strategy is presented, based on the concept of scanning observability, for finite‐dimensional linear systems with discrete observations. It aims to improve the convergence properties of the extended Kalman filter, regarded as an adaptive estimator of the state for the above class of systems. A significant application to a distributed parameter system is shown, related to the problem of determining a convenient trajectory for a moving sensor or a convenient scanning observation rule over a set of fixed sensors. the effectiveness of the resulting filter is analysed on the basis of several numerical experiments.
Signal‐processing‐based performance measures for differential linear repetitive processes
Authors: Smyth K. J. , Cao Y. , Rogers E. , Owens D. H. 
Published: July 2007

AbstractRepetitive or multipass processes are a class of systems characterized by a series of sweeps through a set of dynamics defined over a fixed finite duration. The output of each sweep or pass acts as an explicit forcing function on and hence contributes to the next pass profile. This in turn leads to the unique control problem that the output sequence can contain oscillations which increase in amplitude from pass to pass. In this paper signal‐processing techniques are employed to develop unique computable performance measures of direct use in controller design and related studies.
Parameter bounds for a class of discrete bilinear systems from records with bounded output errors
Authors: Cerone V. 
Published: July 2007

AbstractParameter bounding offers a useful alternative to point parameter estimation methods when either statistical hypotheses on the errors are not met or uncertainties are better characterized in a deterministic way (e.g. systematic, round‐off, truncation errors). So far, many efforts have been devoted to the problem of parameter bounding in linear systems, where exact parameter uncertainty intervals can be computed. In contrast, only partial results have been found for general non‐linear parametrization, namely either upper or lower bounds on parameter uncertainties can be evaluated. In this paper we derive approximate parameter uncertainty intervals for a class of discrete bilinear systems with bounded output errors. This work is based on a linear input‐output parametrization and previous results on bounded errors‐in‐variables models. For an extensively simulated example, central estimates by means of the bounded errors‐in‐variables approach and least squares estimates are computed and compared.
A design method of adaptive load frequency control with dual‐rate sampling
Authors: Yamashita Katsumi , Hirayasu Mitsuru , Okafuji Kei , Mlyagi Hayao 
Published: July 2007

AbstractAn adaptive control strategy for load frequency control, the purpose of which is to reduce the transient errors in the frequency and scheduled tie‐line power deviations and to ensure zero steady state errors of these two quantities, is described. A dual‐rate sampling self‐tuning regulator whereby data sampling and control output are performed at different rates is designed for interconnected power systems with unknown deterministic load disturbances. the proposed control scheme is applied to a two‐area power system provided with reheat thermal turbines and the control effects of the regulator are examined using digital simulation.
Self‐optimization adaptive velocity control of asymmetric hydraulic actuator
Authors: Huang C. H. , Wang Y. T. 
Published: July 2007

AbstractFor the velocity control of an asymmetric hydraulic actuator the servovalve is not operated in the vicinity of zero. Thus the linearized model is not easily defined and the classical controller cannot be readily found. Also, because of its asymmetry, a fixed reference model of adaptive control cannot result in optimal performances for both directions.In this paper, to minimize the performance index associated with the estimated model and control penalty, the self‐optimization α‐adaptive control shows an ability to adapt to variations in directions and operating conditions. Thus it will provide similarly optimal performances for both extending and retracting processes. Then, comparing with the variable gain control, the experimental results clearly show its superior performance and disturbance rejection.
Illuminating Embodiment: Rafael Lozano‐Hemmer's Relational Architectures
Authors: Fernández Maria 
Published: July 2007

AbstractArt and architecture have a strong tradition of humanism in which man and the human body are the centre and measure of all things. Maria Fernández describes the work of artist Rafael Lozano‐Hemmer whose work transgresses and challenges these preconceptions through performance, seeking to expose the body and society's receptivity to instability, fluctuation and re‐imagining. Copyright © 2007 John Wiley & Sons, Ltd.
Concert Hall, Bruges
Authors: Melvin Jeremy 
Published: July 2007

AbstractJeremy Melvin describes how Robbrecht en Daem Architecten's concert hall in Bruges provides one of the most exemplary medieval Flemish cities with a ‘window to modernity’. Exceeding mere juxtaposition of old and new, the architects have created a wholly sensory experience for their concert‐going audience, which embraces the ephemeral quality of musical performance with the physicality of architecture. Copyright © 2007 John Wiley & Sons, Ltd.
3+1 architects
Authors: Kurg Andres 
Published: July 2007

AbstractWithout the predominance of a single presiding tradition of modern architecture in Estonia, the way has been clear for a younger generation of architects to make their mark. Andres Kurg describes the work of 3+1 architects, who launched their career in the mid‐1990s with an Estonian Embassy in Vilnius, Lithuania. Through their trend‐setting domestic work, they have proved able to appeal to a new wealthy client base, while also developing their own interests in programme and architecture's relationship to the physical landscape. Copyright © 2007 John Wiley & Sons, Ltd.
Novel Nanoparticle‐Reinforced Metal Matrix Composites with Enhanced Mechanical Properties
Authors: Tjong S. C. 
Published: July 2007

AbstractThis paper summarizes and reviews the state‐of‐the‐art processing methods, structures and mechanical properties of the metal matrix composites reinforced with ceramic nanoparticles. The metal matrices of nanocomposites involved include aluminum and magnesium. The processing approaches for nanocomposites can be classified into ex‐situ and in‐situ synthesis routes. The ex‐situ ceramic nanoparticles are prone to cluster during composite processing and the properties of materials are lower than the theoretical values. Despite the fact of clustering, ex‐situ nanocomposites reinforced with very low loading levels of nanoparticles exhibit higher yield strength and creep resistance than their microcomposite counterparts filled with much higher particulate content. Better dispersion of ceramic nanoparticles in metal matrix can be achieved by using appropriate processing techniques. Consequently, improvements in both the mechanical strength and ductility can be obtained readily in aluminum or magnesium by adding ceramic nanoparticles. Similar beneficial enhancements in mechanical properties are observed for the nanocomposites reinforced with in‐situ nanoparticles.
Diffraction‐Based Residual Stress Analysis Applied to Problems in the Aircraft Industry
Authors: Staron P. , Cihak U. , Clemens H. , Stockinger M. , Bayraktar F. S. , Koçak M. , Schreyer A. 
Published: July 2007

AbstractCost reduction and weight saving are most important principles governing design and construction of aircrafts. Advanced alloys and thermo‐mechanical treatments as well as new and optimized production processes are being developed. For example, welding of fuselage components like stringers or clips made of Al alloys can have several advantages over riveting. Retention of optimum weld microstructure and properties as well as control of welding related residual stresses and distortion is essential. In the context of risk analysis and damage tolerance it will be of growing importance to study residual stress fields in weld configurations and their influence on fatigue crack propagation. In this paper, methods to evaluate residual stresses in turbine discs and laser welded Al joints are reviewed.
Testing for market power in the Australian grains and oilseeds industries
Authors: O'Donnell Christopher J. , Griffith Garry R. , Nightingale John J. , Piggott Roley R. 
Published: July 2007

AbstractWe formally assess competitive buying and selling behavior in the Australian grains and oilseeds industries using a more realistic empirical model and a less aggregated data set than previously available. We specify a duality model of profit maximization that allows for imperfect competition in both input and output markets and for variable‐proportions technologies. Aggregate input‐output data are used to define the structure of the relevant industries, and time series data are then used to implement the model for 13 grains and oilseeds products handled by seven groups of agents. The model is estimated in a Bayesian econometrics framework. We find evidence of flour and cereal food product manufacturers exerting market power when purchasing wheat, barley, oats and triticale; beer and malt manufacturers exerting market power when purchasing wheat and barley; and other food product manufacturers exerting market power when purchasing wheat, barley, oats and triticale. [EconLit citations: C11, L66, Q11]. © 2007 Wiley Periodicals, Inc. Agribusiness 23: 349–376, 2007.
Obesity and low‐carb diets in the united states: A herd behavior model
Authors: Miljkovic Dragan , Mostad Daniel 
Published: July 2007

AbstractWe propose that consumer herding is a plausible explanation of the popularity of low‐carb diets in the United States. This proposition was empirically tested using per capita consumption of both broilers and eggs as proxies of the popularity of low‐carb diets. Results confirm that people do not always make (perfectly) rational choices, even when a good signal or correct information is available to them. Instead, they choose to do what everyone else is doing. In addition, we could not conclusively determine that an increase in media reports about low‐carb diets led to further increase in the popularity of low‐carb diets. [JEL: D12, D82, Q18]. © 2007 Wiley Periodicals, Inc. Agribusiness 23: 421–434, 2007.
An old threat in a new setting: High prevalence of silicosis among jewelry workers
Authors: Murgia Nicola , Muzi Giacomo , dell'Omo Marco , Sallese Domenico , Ciccotosto Cesario , Rossi Margherita , Scatolini Paola , Zingarelli Alberto , Accattoli Maria Patrizia , Melchiorri Daniela , Abbritti Giuseppe 
Published: July 2007

AbstractBackgroundSilicosis is caused by inhaling free crystalline silica. Few case reports have addressed the risk of silicosis in the jewelry trade where chalk molds containing a high percentage of silica are used in casting. We conducted a cross‐sectional study involving 100 goldsmiths exposed to silica.MethodsAll workers replied to a questionnaire and underwent a clinical examination, pulmonary function tests, a chest X‐ray and a high‐resolution CT scan.ResultsHigh‐resolution CT visualized signs of silicosis in 23 cases, confirmed by standard chest X‐rays in 10. In the 23 workers with CT evidence of silicosis Total Lung Capacity, FEV1 and the Lung Diffusing Capacity did not differ from the workers without the disease. Pulmonary function tests did not correlate with silica exposure.ConclusionIn this study we demonstrate that use of chalk molds in casting in jewelry causes silicosis. The composition of the dust could be responsible of the high prevalence observed. Am. J. Ind. Med. 50:577–583, 2007. © 2007 Wiley‐Liss, Inc.
Carbon black and lung cancer: Testing a new exposure metric in a German cohort
Authors: Morfeld Peter , McCunney Robert J. 
Published: July 2007

AbstractBackgroundA cohort mortality study of a large carbon black production plant in Germany showed an elevation in lung cancer mortality (SMR 1.81 (95% CI: 1.34–2.39)), although the elevation could not be linked to exposure to carbon black.MethodsIn follow up to a British study of carbon black production workers [Sorahan et al., 2007] in which risk of lung cancer progressively declined after cessation of employment—in contrast to an expected upward trend—we evaluated the German cohort with a similar methodology, that is, by focusing on the first 15 years after leaving employment in terms of lung cancer SMR.ResultsIn our SMR analysis of the German cohort of 1,528 men and an inception cohort of 1,271 men, distinctly different results from the British cohort were observed. We observed a rising trend in lung cancer SMR, in contrast to the declining SMR trend noted in the British cohort. In fact, Cox models for lung cancer mortality with attained age as the basic time variable showed negative coefficients for the full and inception cohorts.ConclusionsOur analysis of a large German cohort of carbon black workers does not support the concept of a declining risk of lung cancer following cessation of employment. Am. J. Ind. Med. 50:565–567, 2007. © 2007 Wiley‐Liss, Inc.
Clinical dividends from the molecular genetic diagnosis of craniosynostosis†
Authors: Wilkie Andrew O.M. , Bochukova Elena G. , Hansen Ruth M. S. , Taylor Indira B. , Rannan‐Eliya Sahan V. , Byren Jo C. , Wall Steven A. , Ramos Lina , Venâncio Margarida , Hurst Jane A. , O'Rourke Anthony W. , Williams Louise J. , Seller Anneke , Lester Tracy 
Published: July 2007

AbstractA dozen years have passed since the first genetic lesion was identified in a family with craniosynostosis, the premature fusion of the cranial sutures. Subsequently, mutations in the FGFR2, FGFR3, TWIST1, and EFNB1 genes have been shown to account for ∼25% of craniosynostosis, whilst several additional genes make minor contributions. Using specific examples, we show how these discoveries have enabled refinement of information on diagnosis, recurrence risk, prognosis for mental development, and surgical planning. However, phenotypic variability can present a significant challenge to the clinical interpretation of molecular genetic tests. In particular, the difficulty of analyzing the complex interaction of genetic background and prenatal environment in determining clinical features, limits the value of identifying low penetrance mutations. © 2007 Wiley‐Liss, Inc.
Die aktiven Zentren in manganhaltigen Metalloproteinen und anorganische Modellkomplexe
Authors: Wieghardt Karl 
Published: July 2007

AbstractMangan ist ein essentielles Ultraspurenelement, das Bestandteil der aktiven Zentren einer Reihe von Metalloproteinen ist. Mehrere Metalloproteine enthalten zwei (oder mehr) Manganatome pro Untereinheit. Strukturelle Merkmale dieser Metalloproteine und die experimentellen Grundlagen für die Strukturvorschläge werden in dieser Übersicht beschrieben. Parallel zu den Anstrengungen von Biochemikern, die die Funktion isolierter Enzyme auf molekularer Ebene zu verstehen versuchen, haben in den letzten Jahren Anorganiker die Koordinationschemie zwei‐ oder mehrkerniger Mangankomplexe mit O,N‐Donoratomen und verbrückenden O,N‐Liganden untersucht. Eine große Zahl solcher Komplexe wurde synthetisiert, ihre Strukturen wurden röntgenographisch bestimmt und ihre magnetischen und spektroskopischen Eigenschaften im Detail studiert. Die zum Teil verblüffenden Ähnlichkeiten der elektronischen und spektroskopischen Eigenschaften dieser Modellverbindungen mit denen der Biomoleküle haben zu einem tieferen Verständnis der Strukturen und manchmal auch der Funktion der Metalloproteine geführt. Das interdisziplinäre, fruchtbare Zusammenspiel zwischen Physikern, Biochemikern und Anorganikern wird hier am Beispiel manganhaltiger Metalloproteine mit polynuclearen aktiven Zentren dargestellt.
Ein bicyclisches Isomer der closo‐Carbaborane (CH)2(BR)4
Authors: Krämer Albrecht , Pritzkow Hans , Siebert Walter 
Published: July 2007

Elektronendonor‐Substituenten am Bor sollten die Organoboran‐Struktur 3 gegenüber den Strukturen der closo‐Carbaborane 1 und 2 stabilisieren. Lipscomb et al. hatten vorausgesagt, daß 3 als Intermediat bei der Umlagerung von 1 in 2 auftritt. Jetzt gelang die Synthese von 3 (R = NiPr2) ausgehend von 1,1,2,2‐Tetrakis(dichlorboryl)ethan über eine partielle Aminierung mit HNiPr2 sowie eine nachfolgende Enthalogenierung mit Na/K‐Legierung.magnified image
Synthesen, Konformationen und Röntgenstrukturanalysen von Saccharidketten der Core‐Regionen von Glycoproteinen
Authors: Paulsen Hans 
Published: July 2007

AbstractBei Glycoproteinen kann der kovalent gebundene Kohlenhydratteil intramolekular das Proteinmolekül stabilisieren, oder er kann eine intermolekulare Funktion bei der biologischen Erkennung ausüben. Die Entdeckung dieser biologischen Phänomene hat zur Renaissance der Chemie und Biochemie der Kohlenhydrate geführt. Sowohl N‐Glycoproteine als auch O‐Glycoproteine haben in der Bindungsregion zum Protein spezielle invariante Oligosaccharidketten, die als Core‐Regionen bezeichnet werden. Diese Übersicht beschreibt die vielfältigen Synthesewege für Oligosaccharide, über die man zu den Core‐Basisstrukturen gelangt. Die Methoden der Oligosaccharidsynthese sind so verbessert, daß auch Strukturen des komplexen Lactosamintyps und des „bisected”︁ Typs bis zum Nona‐ bzw. Undecasaccharid synthetisiert werden können. Oligosaccharidketten sind wesentlich weniger flexibel als Peptidketten. NMR‐spektroskopisch lassen sich die bevorzugten Konformationen in Lösung sehr gut ermitteln. Bei einem verzweigten Octasaccharid ist ein Vergleich der Konformationen in Lösung und im Kristall möglich. Oligosaccharide können an die Amidgruppe von Asparagin oder an die Hydroxygruppe von Serin oder Threonin geknüpft werden. Bei entsprechenden Blockierungsfunktionen lassen sich die erhaltenen Glycosylaminosäuren C‐oder N‐terminal mit Aminosäuren verlängern. Man gelangt so zu beliebigen Glycopeptidsequenzen. Im Bereich der Verknüpfungsregion sind bei Glycopeptiden bestimmte Konformationen bevorzugt. Eine zukunftsträchtige Aufgabe im Hinblick auf die Funktion der Glycoproteine dürfte die Synthese und biochemische Untersuchung von modifizierten Glycoproteinsegmenten sein.
Chemie der Polyoxometallate: Aktuelle Variationen über ein altes Thema mit interdisziplinären Bezügen
Authors: Pope Michael T. , Müller Achim 
Published: July 2007

AbstractDie Verbindungsklasse der Metall‐Sauerstoff‐Clusteranionen ist nicht nur einzigartig hinsichtlich ihrer topologischen und elektronischen Vielfalt — sie hat auch erhebliche Bedeutung für ganz unterschiedliche Disziplinen. So sind die früheren Arbeiten auf diesem Forschungsgebiet mit Namen wie Berzelius, Werner und Pauling verbunden. Derartige Cluster (man nennt sie üblicherweise Isopoly‐ und Heteropolyanionen) enthalten häufig hochsymmetrische, oft angenähert kugelförmige Anordnungen von MOx‐Einheiten (z. B. M = V, Mo, W), und ihre Strukturen basieren häufig auf Archimedischen und Platonischen Körpern. Letztere sind von beträchtlichem topologischem Interesse. Noch wissen wir nicht, worin eigentlich die Triebkraft zur Bildung solcher polynuclearer Cluster besteht. Polyoxoanionen sind wichtige Modelle zum Verständnis der biologischen und katalytischen Wirkung von Metall‐Chalcogenid‐Clustern, da die Metall‐Metall‐Wechselwirkungen von sehr gering (oder nicht vorhanden) bis stark (Metall‐Metall‐Bindungen) reichen können. Grundsätzlich lassen sich diese Wechselwirkungen durch die Wahl des Metalls (3d, 4d, 5d), durch Veränderung der Elektronenpopulation (Grad der Reduktion) und den Umfang der Protonierung beeinflussen. Gemischtvalente Vanadate können beispielsweise nacheinander mehrere Elektronen ohne Spinpaarung aufnehmen, d.h. die magnetischen Eigenschaften dieser Komplexe lassen sich schrittweise über einen weiten Bereich variieren. Viele Vanadate wirken als Cryptanden oder Clathrat‐Wirte für Neutralmoleküle und Kationen, und, was neu ist, auch für Anionen, wobei meistens ein bemerkenswerter „induzierter Selbstorganisationsprozeß”︁ abläuft. Anwendung finden Polyoxometallate in der Analytischen und Klinischen Chemie, in der Katalyse (einschließlich Photokatalyse), in der Biochemie (Inhibierung von Elektronentransfer‐Prozessen), in der Medizin (antitumorale, antivirale und sogar anti‐HIV‐Aktivität) und bei der Herstellung von integrierten Schaltungen, alles Gebiete von aktuellem Interesse. Metall‐Sauerstoff‐Cluster treten auch in der Geosphäre — die gemischtvalenten Vanadate ermöglichen ein Verständnis der überaus vielfältigen Geochemie dieses Metalls — und möglicherweise auch in der Biosphäre auf. Zwischen der Chemie der Polyoxoanionen und der Thioanionen derselben Elemente bestehen wichtige Unterschiede, die für die heterogene Katalyse, die Bioanorganische Chemie und die Veterinärmedizin von Bedeutung sind.
Selektive Halogenierung von Cyclomaltooligosacchariden in C6‐Position und Synthese von Per(3,6‐anhydro)cyclomaltooligosacchariden
Authors: Gadelle Andrée , Defaye Jacques 
Published: July 2007

Cyclodextrin‐Derivate 2 mit Glucopyranose‐Einheiten in 1C4‐Konformation wurden über die 6‐iodierten Verbindungen 1 erhalten. Die Synthese von 1 gelang durch Umsetzung der unsubstituierten Zucker mit Reagentien vom Vilsmeier‐Typ. (Siehe auch folgenden Beitrag.) magnified image