bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observer design for nonlinear discrete‐time systems: Immersion and dynamic observer error linearization techniques
Authors: Zhang Jian , Feng Gang , Xu Hongbing 
Published: April 2009

AbstractThis paper focuses on the observer design for nonlinear discrete‐time systems by means of nonlinear observer canonical form. At first, sufficient and necessary conditions are obtained for a class of autonomous nonlinear discrete‐time systems to be immersible into higher dimensional observer canonical form. Then a method called dynamic observer error linearization is developed. By introducing a dynamic auxiliary system, the augmented system is shown to be locally equivalent to the generalized observer form, whose nonlinear terms contain auxiliary states and output of the system. A constructive algorithm is also provided to obtain the state coordinate transformation. These results are an extension of their counterparts of nonlinear continuous‐time systems to nonlinear discrete‐time systems (Syst. Control Lett. 1986; 7:133–142; SIAM. J. Control Optim. 2003; 41:1756–1778; Int. J. Control 2004; 77:723–734; Automatica 2006; 42:321–328; IEEE Trans. Automat. Control 2007; 52:83–88; IEEE Trans. Automat. Control 2004; 49:1746–1750; Automatica 2006; 42:2195–2200; IEEE Trans. Automat. Control 1996; 41:598–603; Syst. Control Lett. 1997; 31:115–128). Copyright © 2009 John Wiley & Sons, Ltd.
Stability and stabilization of discrete‐time singular Markov jump systems with time‐varying delay
Authors: Ma Shuping , Boukas El‐Kébir , Chinniah Y. 
Published: April 2009

AbstractThe stochastic stability and stochastic stabilization of time‐varying delay discrete‐time singular Markov jump systems are discussed. For full and partial knowledge of transition probabilities cases, delay‐dependent linear matrix inequalities (LMIs) conditions for the systems to be regular, causal and stochastically stable are given. Sufficient conditions are proposed for the existence of state feedback controller in terms of LMIs. Finally, two numerical examples to illustrate the effectiveness of the method are given. Copyright © 2009 John Wiley & Sons, Ltd.
Alliance partners and firm performance: resource complementarity and status association
Authors: Lin Zhiang (John) , Yang Haibin , Arya Bindu 
Published: April 2009

AbstractBridging the resource‐based view and the institutional perspective, this study explores the performance consequences of firms' alliance partner selections by examining the interactions of resource complementarity and institutional associations (reflected through both societal and network status) between the firm and its partners. The integrative framework suggests that a joint consideration of resource complementarity and status effects, as well as important firm‐ and environmental‐level contingent factors, are critical for understanding the underlying mechanisms of alliance formations and their effects on firm performance. Further, our study suggests that it is necessary to consider both societal and network status as they can have distinct effects under certain conditions. Our analyses of four U.S. industries (computer, steel, pharmaceutics, crude petroleum and natural gas) over a span of 13 years largely support our framework. Copyright © 2009 John Wiley & Sons, Ltd.
Structural homophily or social asymmetry? The formation of alliances by poorly embedded firms
Authors: Ahuja Gautam , Polidoro Francisco , Mitchell Will 
Published: April 2009

AbstractRecent research shows that preexisting network structure constrains the formation of new interorganizational alliances. Firms that are poorly embedded in a network structure are less likely than richly embedded firms to form alliances, because they lack informational and reputational benefits. This study examines the types of ties that poorly embedded firms can form to overcome the constraints that their structural positions impose, in turn helping to explain how firms' actions can transform existing network structures. We argue that poorly embedded firms are more likely to participate in ties characterized by social asymmetry than in ties characterized by structural homophily. We analyze the terms of trade that socially asymmetric partners negotiate for alliance governance and discuss how such alliances influence network dynamics. To test our arguments, we use longitudinal data on the alliance activities of 97 global chemical firms from 1979 to 1991. Copyright © 2009 John Wiley & Sons, Ltd.
Improved Hybrid Solar Cells via in situ UV Polymerization
Authors: Tepavcevic Sanja , Darling Seth B. , Dimitrijevic Nada M. , Rajh Tijana , Sibener Steven J. 
Published: April 2009

AbstractOne approach for making inexpensive inorganic–organic hybrid photovoltaic (PV) cells is to fill highly ordered TiO2 nanotube (NT) arrays with solid organic hole conductors such as conjugated polymers. Here, a new in situ UV polymerization method for growing polythiophene (UV‐PT) inside TiO2 NTs is presented and compared to the conventional approach of infiltrating NTs with pre‐synthesized polymer. A nanotubular TiO2 substrate is immersed in a 2,5‐diiodothiophene (DIT) monomer precursor solution and then irradiated with UV light. The selective UV photodissociation of the CI bond produces monomer radicals with intact π‐ring structure that further produce longer oligothiophene/PT molecules. Complete photoluminescence quenching upon UV irradiation suggests coupling between radicals created from DIT and at the TiO2 surface via a charge transfer complex. Coupling with the TiO2 surface improves UV‐PT crystallinity and π–π stacking; flat photocurrent values show that charge recombination during hole transport through the polymer is negligible. A non‐ideal, backside‐illuminated setup under illumination of 620‐nm light yields a photocurrent density of ≈5 µA cm2—surprisingly much stronger than with comparable devices fabricated with polymer synthesized ex situ. Since in this backside architecture setup we illuminate the cell through the Ag top electrode, there is a possibility for Ag plasmon‐enhanced solar energy conversion. By using this simple in situ UV polymerization method that couples the conjugated polymer to the TiO2 surface, the absorption of sunlight can be improved and the charge carrier mobility of the photoactive layer can be enhanced.
Ionic‐Liquid‐Assisted Sonochemical Synthesis of Carbon‐Nanotube‐Based Nanohybrids: Control in the Structures and Interfacial Characteristics
Authors: Park Ho Seok , Choi Bong Gill , Yang Seong Ho , Shin Weon Ho , Kang Jeung Ku , Jung Doohwan , Hong Won Hi 
Published: April 2009

AbstractA versatile, facile, and rapid synthetic method of advanced carbon nanotube (CNT)‐based nanohybrid fabrication, or the so‐called ionic‐liquid‐assisted sonochemical method (ILASM), which combines the supramolecular chemistry between ionic liquids (ILs) and CNTs with sonochemistry for the control in the size and amount of uniformly decorated nanoparticles (NPs) and interfacial engineering, is reported. The excellence in electrocatalysis of hybrid materials with well‐designed nanostructures and favorable interfaces is demonstrated by applying them to electrochemical catalysis. The synthetic method discussed in this report has an important and immediate impact not only on the design and synthesis of functional hybrid nanomaterials by supramolecular chemistry and sonochemistry but also on applications of the same into electrochemical devices such as sensors, fuel cells, solar cells, actuators, batteries, and capacitors.
Regression testing with UML software designs: A survey
Authors: Mahdian Alireza , Andrews Anneliese Amschler , Pilskalns Orest Jacob 
Published: April 2009

AbstractThe unified modeling language (UML) designs come in a variety of different notations. UML designs can be quite large and interactions between various notations and the models they define can be difficult to assess. During the design phase, and between successive releases of systems, designs change. The impact of such changes and the resulting effect on behavior can be non‐obvious and difficult to assess. This survey article explores techniques for such re‐evaluation that can be classified as regression testing and suggests regression testing criteria for designs. These might vary depending on testing objectives and include both selective and regenerative regression testing approaches. The article provides a concise overview of regression testing approaches related to various UML design notations including use cases, class diagrams, sequence diagrams, activity diagrams, and statecharts, as well as combinations of these models. It discusses UML‐related techniques involving cost and prioritization during selective regression testing. Finally, it evaluates these techniques with respect to inclusiveness, precision, efficiency, generality, accountability, and safety. An example is used throughout to illustrate how the techniques work. Copyright © 2009 John Wiley & Sons, Ltd.
Fractal behaviour of complex systems
Authors: Morales‐Matamoros Oswaldo , Tejeida‐Padilla Ricardo , Badillo‐Piña Isaias 
Published: April 2009

AbstractOne of the most important properties of systems is complexity. In a simple way, we can define the complexity of a system in terms of the number of elements that it contains, the nature and number of interrelations and the number of levels of embeddedness. When a high level of complexity exists in a system, it is considered a complex system. Complex systems can be soft systems and hard systems. In hard systems, when their elements are interrelated in a non‐linear way, they are considered complex systems when they contain a great number of elements interacting in a non‐linear way. To try to understand the behaviour of this type of system diverse mathematical tools have been developed. A new scientific discipline with great impact in the analysis of the complex systems has been developed in recent years, called fractal analysis. The study of the complex systems in the framework of fractal theory has been recognized as a new scientific discipline, being sustained by advances that have been made in diverse fields ranging from physics to economics. In this paper the history and the basic concepts of the fractal analysis of complex systems are discussed briefly and an oil crude price volatility fractal analysis is provided. Copyright © 2009 John Wiley & Sons, Ltd.
Variables affecting physics achievement
Authors: Lawrenz Frances , Wood Nathan B. , Kirchhoff Allison , Kim Nam Keol , Eisenkraft Arthur 
Published: April 2009

AbstractMuch research has focused on student views about physics concepts, with an emphasis on the identification of alternative conceptions, and how curricula and professional development may ameliorate the situation. However, there has been little work on determining the extent of, and in separating, the student and teacher/classroom level variables that may impact student physics achievement. This study examined the effect of different student and teacher/classroom level variables on student understanding of physics concepts using hierarchical linear modeling (HLM), a regression based technique. The data were collected from 68 different teachers and 3,119 students who were using a reform curriculum, Active Physics. Teachers and students completed surveys asking about their beliefs, their classes and their personal characteristics. Students also completed a physics achievement test. The data show that students of teachers who used Active Physics for a greater portion of the year scored higher on the achievement test than did students of teachers who did not use the curriculum as much. Furthermore, the data show that the achievement gap was narrowed between boys and girls and between students with different attitudes toward physics. Additionally teachers who received inservice instruction on how to implement Active Physics narrowed the gap between students with different views of their classroom involvement. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 961–976, 2009
Identifying meta‐clusters of students' interest in science and their change with age
Authors: Baram‐Tsabari Ayelet , Yarden Anat 
Published: April 2009

AbstractNearly 6,000 science questions collected from five different web‐based, TV‐based and school‐based sources were rigorously analyzed in order to identify profiles of K‐12 students' interest in science, and how these profiles change with age. The questions were analyzed according to their topic, thinking level, motivation for and level of autonomy in raising the question, the object of interest and its magnitude, and psychological distance of the object in question from the asker. Characteristics of the asker, such as gender, grade level, and country of origin were also considered, alongside characteristics of the data source, such as language, setting (Internet, school, TV), and the potential science‐attentiveness of the users. Six meta‐clusters of children's and adolescents' interest in science were identified using cluster analysis of their self‐generated science questions. A developmental shift in interest from non‐classical to classical school science subjects was noted. Other age‐related developments, such as an increase in thinking level as reflected by the questions, a decrease in organization level and the psychological distance of the object in question with age were also explored. Advantages and shortcomings of web‐based data collection for educational research are discussed, as are the implications of the results obtained using this methodology for formal science education. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 999–1022, 2009
The effects of Common Knowledge Construction Model sequence of lessons on science achievement and relational conceptual change
Authors: Ebenezer Jazlin , Chacko Sheela , Kaya Osman Nafiz , Koya Satya Kiran , Ebenezer Devairakkam Luke 
Published: April 2009

AbstractThe purpose of this study was to investigate the effects of the Common Knowledge Construction Model (CKCM) lesson sequence, an intervention based both in conceptual change theory and in Phenomenography, a subset of conceptual change theory. A mixed approach was used to investigate whether this model had a significant effect on 7th grade students' science achievement and conceptual change. The Excretion Unit Achievement Test (EUAT) indicated that students (N = 33) in the experimental group achieved significantly higher scores (p < 0.001) than students in the control group (N = 35) taught by traditional teaching methods. Qualitative analysis of students' pre‐ and post‐teaching conceptions of excretion revealed (1) the addition and deletion of ideas from pre‐ to post‐teaching; (2) the change in the number of students within categories of ideas; (3) the replacement of everyday language with scientific labels; and (4) the difference in the complexity of students' responses from pre‐ to post‐teaching. These findings contribute to the literature on teaching that incorporates students' conceptions and conceptual change. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 25–46, 2010
Rethinking the introduction of particle theory: A substance‐based framework
Authors: Johnson Philip , Papageorgiou George 
Published: April 2009

AbstractIn response to extensive research exposing students' poor understanding of the particle theory of matter, this article argues that the conceptual framework within which the theory is introduced could be a limiting factor. The standard school particle model is characterized as operating within a “solids, liquids, and gases” framework. Drawing on an analysis of scientific ideas on matter and research into students' understanding, issues arising from the framework are identified which could contribute towards students' well known difficulties. The analysis leads to the proposal for a particle model based within the framework of the concept of a substance. Results from two exploratory studies using the substance‐based particle model with children (ages 9–10) in two contrasting elementary schools in England are then reported. After a short teaching intervention with a class in each school, individual interviews were held with a sample of 12 students from each class. Data were collected on students' understanding of substances coexisting in different room temperature states and phenomena involving changes of state and mixing. The results gave useful feedback on the specification of the model and its teaching. Overall the students' engagement with the particle ideas was encouraging and suggests a larger scale testing of the substance‐based model is merited. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47:130–150, 2010
Hypoplastic left heart syndrome diagnosed in fetal life: associated findings, pregnancy outcome and results of palliative surgery
Authors: Galindo A. , Nieto O. , Villagrá S. , Grañeras A. , Herraiz I. , Mendoza A. 
Published: April 2009

AbstractObjectivesTo analyze the main prenatal characteristics of hypoplastic left heart syndrome (HLHS), its association with extracardiac anomalies including increased nuchal translucency (NT) and the outcome of affected patients.MethodsWe searched our database for classical forms of HLHS (aortic atresia, mitral and aortic atresia and critical aortic stenosis evolved to a severely hypoplastic left ventricle) prenatally diagnosed between 1998 and 2006. Data on 101 fetuses were retrieved and analyzed.ResultsThe main reason for referral was suspected heart defect on a routine ultrasound scan (82%). The mean gestational age at diagnosis was 21 weeks. Most cases were detected at ≤ 22 weeks (72%), the upper limit for termination of pregnancy (TOP) in our country (Spain). An intact atrial septum was diagnosed in 11 of the 58 fetuses (19%) in which pulmonary vein blood flow was assessed, and this diagnosis was proved to be correct in the six liveborn babies. Most fetuses (68%) had an isolated HLHS. Fourteen fetuses (14%) were chromosomally abnormal and all had associated extracardiac defects. NT was above the 95th centile in 21 of the 74 cases (28%) in which this measurement was available. 79% (58/73) of the cases in which HLHS was detected at ≤ 22 weeks were terminated, and no differences in the rate of TOP were found through the study period. Among the 43 continuing pregnancies, seven fetuses died in utero and there were 36 live births; in 12 cases the parents opted for compassionate care and 24 chose to have the infant surgically treated. In the cohort of intention‐to‐treat cases, the overall survival rate was 36% (9/25). This rate improved from 18% (2/11) in the period 1998–2002 to 50% (7/14) in 2003–2006. There were no survivors in cases with intact atrial septum or when there were associated defects. At follow‐up, 2/9 survivors suffered from significant neurological morbidity.ConclusionsFetal echocardiography allows an accurate diagnosis of HLHS, which is made in most instances in the first half of pregnancy. Despite the advantage offered by the prenatal detection of HLHS, which provides the opportunity to plan perinatal management, our up‐to‐date results show that the outlook for these fetuses is still poor, and highlight the importance of presenting these figures when counseling parents with affected fetuses. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
X‐ray scattering information of ED‐XRF technique for powdered fruit juice mixes
Authors: Sussulini A. , Lima A. G. , Figueiredo E. C. , Fernandes H. L. , Pinheiro S. C. L. , Bueno M. I. M. S. , Pereira F. M. V. 
Published: April 2009

AbstractThe initial main objective of this study was to evaluate the potentiality of energy‐dispersive x‐ray fluorescence (ED‐XRF) and principal component analysis (PCA) for qualitative analysis of artificial powdered fruit juice mixes. The X‐ray spectroscopy (XRS) technique can be useful for preliminary studies of food and beverage samples, such as metal content in this type of sample. In addition, sample pretreatment is not required, offering very fast acquisition of results. XRF spectra were obtained using an ED‐XRF system equipped with an Rh target x‐ray tube. The spectral region related to x‐ray scattering from the light elements (C, H, and O, among others) of the samples matrix. Specifically, x‐ray scattering was verified in the region (from 18.00 to 24.00 keV) where Compton and Rayleigh effects occur by the x‐ray source of conventional equipment of ED‐XRF. This region combined with PCA showed distinction of the samples with and without artificial sweeteners in their composition. In addition, two different artificial sweeteners (aspartame and cyclamate) were detected by x‐ray scattering. These results have paved way for the versatile ED‐XRF application for analyses of inorganic and organic composition in food and beverage samples, without pretreatment. Copyright © 2009 John Wiley & Sons, Ltd.
Accurate determination of the Ca:P ratio in rough hydroxyapatite samples by SEM‐EDS, PIXE and RBS—a comparative study
Authors: Bailey M. J. , Coe S. , Grant D. M. , Grime G. W. , Jeynes C. 
Published: April 2009

AbstractThe Ca:P ratio in a certified standard of hydroxyapatite was determined by X‐ray spectrometry (XRS), with the X‐rays excited by both electrons and ions using energy dispersive spectroscopy on the scanning electron microscope (SEM‐EDS) and particle‐induced X‐ray emission (PIXE). The certified value of Ca:P was accurately verified by 3 MeV 4He+ Rutherford Backscattering Spectrometry (RBS). We show that the demonstrably rough surface of this sample does not cause perturbation of the Ca:P ratio within the uncertainties of each of the XRS measurements. Copyright © 2009 John Wiley & Sons, Ltd.
Chemical composition and mass closure for PM10 aerosols during the 2005 dry season at a rural site in Morogoro, Tanzania
Authors: Mkoma Stelyus L. , Maenhaut Willy , Chi Xuguang , Wang Wan , Raes Nico 
Published: April 2009

AbstractAn intensive aerosol field campaign was carried out from 11 July to 11 August 2005 (dry season) at a rural site in Morogoro, Tanzania. The objectives were to determine the chemical composition of the atmospheric particulate matter (PM) and to examine to which extent the gravimetric PM mass can be explained by the measured aerosol components. Two low‐volume filter samplers were deployed, a PM10 filter holder with two Whatman QM‐A quartz fibre filters in series and a Gent PM10 stacked filter unit (SFU) sampler with coarse and fine Nuclepore polycarbonate filters. The samplers operated in parallel and a total of 51 parallel collections were made. All samples were analysed for the PM mass by weighing. Depending on the sampler type and/or collection substrate, further analyses were performed for 25 elements by particle‐induced x‐ray emission spectrometry, for major water‐soluble inorganic ions by ion chromatography, and for organic carbon and elemental carbon by a thermal—optical transmission technique. The PM10 mass, as derived from the SFU samples, was, on an average, 46 ± 12 µg/m3. Aerosol chemical mass closure calculations were made for this PM10 mass; eight aerosol components were considered and they explained 93% of the average PM10 mass. Organic matter (OM) and crustal matter were the dominant aerosol components; they accounted for, on an average, 44% and 33%, respectively, of the PM10 aerosol. The large contribution from OM is thought to originate mainly from the burning of biomass, especially of charcoal and agricultural residues. Copyright © 2009 John Wiley & Sons, Ltd.
“A New Sodium Borate: Na[B6O8(OH)3]·6H2O·H3BO3”
Authors: Köse Dursun Ali , Zümreoglu‐Karan Birgül , Hökelek Tuncer , Sahin Ertan 
Published: April 2009

AbstractThe original article to which this Erratum refers was published in Zeitschrift für Anorganische und Allgemeine Chemie 635 (3) 2009, 563‐566: DOI 10.1002/zaac.200801288.The first formula in the Abstract is incorrect and should be replaced by Na[B6O8(OH)3]·6H2O·H3BO3