bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly Dispersed Mixed Zirconia and Hafnia Nanoparticles in a Silica Matrix: First Example of a ZrO2–HfO2–SiO2 Ternary Oxide System
Authors: Armelao L. , Bertagnolli H. , Bleiner D. , Groenewolt M. , Gross S. , Krishnan V. , Sada C. , Schubert U. , Tondello E. , Zattin A. 
Published: May 2007

AbstractZrO2 and HfO2 nanoparticles are homogeneously dispersed in SiO2 matrices (supported film and bulk powders) by copolymerization of two oxozirconium and oxohafnium clusters (M4O2(OMc)12, M = Zr, Hf; OMc = OC(O)–C(CH3)CH2) with (methacryloxypropyl)trimethoxysilane (MAPTMS, (CH2C(CH3)C(O)O)–(CH2)3Si(OCH3)3). After calcination (at a temperature ≥800 °C), a silica matrix with homogeneously distributed MO2 nanocrystallites is obtained. This route yields a spatially homogeneous dispersion of the metal precursors inside the silica matrix, which is maintained during calcination. The composition of the films and the powders is studied before and after calcination by using Fourier transform infrared (FTIR) analysis, X‐ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled plasma mass spectrometry (LA‐ICPMS). The local environment of the metal atoms in one of the calcined samples is investigated by using X‐ray Absorption Fine Structure (XAFS) spectroscopy. Through X‐ray diffraction (XRD) the crystallization of Hf and Zr oxides is seen at temperatures higher than those expected for the pure oxides, and transmission electron microscopy (TEM) shows the presence of well‐distributed and isolated crystalline oxide nanoparticles (5–10 nm).
Fatal Loeffler's endocarditis due to hypereosinophilic syndrome
Authors: Chao Bo H. , Cline‐Parhamovich Karen , Grizzard John D. , Smith Thomas J. 
Published: May 2007

AbstractHypereosinophilic syndrome (HES) is a rare disorder that can manifest in various organ systems. We report the case of a 54‐year‐old woman with a remote history of seizure disorder who presented with early signs of right‐sided heart failure. Laboratory studies showed significant eosinophilia (8 × 109 l−1). Computed tomography showed heterogeneity of the liver, mild ascites, moderate pleural effusion, multiple small pulmonary emboli, and a large right ventricular mass. Cardiac magnetic resonance imaging demonstrated that the right ventricular mass was due to thrombus and extensive endomyocardial fibrosis, consistent with Loeffler's endocarditis. Bone marrow biopsy showed marked eosinophilia but no abnormal myeloid maturation or a lymphoproliferative disorder; flow cytometry showed no clonality. Extensive infectious, immunologic, and toxicological studies were negative. Despite resolution of peripheral eosinophilia with medical management, including corticosteroids and cytotoxic agents, anticoagulation for pulmonary emboli and ventricular thrombus, and conventional treatment for heart failure, she developed worsening anasarca and died from ventricular fibrillation within 4 weeks of presentation. Autopsy confirmed the diagnosis. Loeffler's endocarditis, usually a late manifestation of HES, is characterized by fibrous thickening of the endocardium, leading to apical obliteration and restrictive cardiomyopathy, resulting in heart failure, thromboembolic events, or atrial fibrillation. HES is a potentially fatal disease with less than 50% reported 10‐year survival. This case presentation is unusual in its rapidly progressive course leading to sudden death. Am. J. Hematol. 82:920–923, 2007. © 2007 Wiley‐Liss, Inc.
Zur Frage des Vorhandenseins von festem Stickstoff in der Erdatmosphäre
Authors: Pelzer Heinz 
Published: May 2007

AbstractMit Hinblick auf die Vegardsche Nordlichthypothese wird untersucht, ob die höheren Atmosphärenschichten im Strahlungsgleichgewichte mit der Erd‐ und Sonnenstrahlung eine Temperatur erreichen können, die unterhalb des Schmelzpunktes von Stickstoff (36° K) liegt. Es ergibt sich, daß diese Temperatur auch auf der Nachtseite der Erde nur unter folgenden Voraussetzungen erreicht werden könnte: Bei Annahme einer gleichförmigen (grauen) Absorption müßten die tieferen Atmosphärenschichten die Erdstrahlung so gut wie vollkommen (bis auf einen Bruchteil 10−1430) absorbieren, oder aber selektiv bloß im Ultrarot mindestens 99,5 Proz. der Strahlung dieses selektiv absorbierten Spektralbereiches. Da diese Voraussetzungen schwerlich zutreffen können, scheint die Vegardsche Nordlichthypothese aus thermodynamischen Gründen allein schon abzulehnen zu sein.
Behavior of composite materials under microorganisms of soil
Authors: Legonkova O. A. , Selitzkaya O. V. 
Published: May 2007

AbstractThe article is devoted to the investigation of the dynamics of fungi and bacteria growth in different types of soil in dependence on the presence of composite materials based on polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Studies on the preparation of branched polymers from styrene and divinylbenzene
Authors: Honglan Tang , Fanghong Gong , Chunlin Liu , Qiang Ren , Yang Yang , Bibiao Jiang , Chao Liu , Jianhai Chen 
Published: May 2007

AbstractThe self‐condensing vinyl polymerization of styrene and an inimer formed in situ by atom transfer radical addition from divinylbenzene and 2‐bromoisobutyl‐tert‐butyrate using atom transfer radical polymerization technique was studied. To study the polymerization mechanism and achieve high molecular weight polymer in a high polymer yield, the polymerization was carried out in bulk at 80°C. Proton nuclear magnetic resonance (1H‐NMR) spectroscopy and gel permeation chromatography (GPC) coupled with multiangle laser light scattering (MALLS) were used to monitor the polymerization process and characterize the solid polymers. It is proved that the polymerization shows a “living” polymerization behavior and the crosslinking reaction has been restrained effectively due to the introduction of styrene. Polymers with high molecular weight (Mw.MALLS > 105) can be prepared in high yield (near 80%). Comparison of the apparent molecular weights measured by GPC with the absolute values measured by MALLS indicates the existence of branched structures in the prepared polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
The effect of photoperiod and prey density on long‐term survival of larvae—a data analytic approach where no parametric model is assumed and individual follow‐up is not available
Authors: Schechtman Edna , Wax Yochanan , Tandler Amos 
Published: May 2007

AbstractA data analytic approach for analysing differences in long‐term survival and identifying treatment combinations which provide high survival in a factorial design set‐up is presented. The methods are particularly appropriate when individual follow‐up data are not available and no simple model fits the data. Upper quantiles of the survival distributions are used as the response variable and within and between‐treatment differences are analysed through both a structured ANOVA model and subset‐selection procedure. The methods are used to study the effects of several photoperiods and prey density treatments on the long‐term survival of the larvae of gilthead seabream,Sparus aurata.The two approaches used are shown to lead to similar conclusions.
A strategy for analysing mixed and pooled exponentials
Authors: Grego John , Hsi Hsiu‐Li , Lynch James 
Published: May 2007

AbstractIt is shown that a linear plot of the mean residual life on the failure rate characterizes the mixture of two exponentials. This plot is used to estimate the two components in the mixing distribution with the two largest mixing proportions. The EM algorithm is then used with these as initial values to obtain the MLE. Gradient plots are used to see if a higher‐order fit is needed. A heuristic is given on how to use the gradient plots to identify components in the higher‐order fit when this is the case. Graphs of an assignment function are then used to determine if the data are from a mixed model or simply the effect of pooling.
Mixed parallel processors with interdependent blocking
Authors: Van Dijk Nico M. 
Published: May 2007

AbstractThis paper studies a system of parallel service facilities or processors with mixed exponential and non‐exponential queues, a non‐exponential finite source input and interdependent arrival as well as departure blocking such as due to a common pool or shared resource. A concrete invariance condition upon the blocking protocol is provided. Under this condition the stationary busy source distribution is shown to be of an insensitive product form. The result unifies and extends known product form results as will be illustrated by several examples.
Searching for knowledge in a world flooded with facts
Authors: Michalski R. S. 
Published: May 2007

AbstractThe wide availability of computer technology and large electronic storage media has led to an enormous proliferation of databases in almost every area of human endeavour. This naturally creates an intense demand for powerful methods and tools for data analysis. Current methods and tools are primarily oriented toward extracting numerical and statistical data characteristics. While such characteristics are very important and useful, they are often insufficient. A decision maker typically needs an interpretation of these findings, and this has to be done by a data analyst. With the growth in the amount and complexity of the data, making such interpretations is an increasingly difficult problem. As a potential solution, this paper advocates the development of methods for conceptual data analysis. Such methods aim at semi‐automating the processes of determining high‐level data interpretations, and discovering qualitative patterns in data. It is argued that these methods could be built on the basis of algorithms developed in the area of machine learning. An exemplary system utilizing such algorithms, INLEN, is discussed. The system integrates machine learning and statistical analysis techniques with database and expert system technologies. Selected capabilities of the system are illustrated by examples from implemented modules.
Recent advances in automatic classification
Authors: Michaud P. 
Published: May 2007

AbstractTraditional classification methods are divided into two broad types: hierarchical methods and non‐hierarchical methods in which the number of classes has to be fixed in advance. Both methods can handle both quantitative and qualitative data. A third type finds a partition optimizing a linear classification criterion (e.g. the Condorcet criterion) in which the number of classes does not have to be fixed in advance, but the data must be qualitative. A recent generalization, the ‘S theory’ can handle simultaneously both quantitative and qualitative data, and both linear and non‐linear classification criteria (in the space of paired comparisons of elements). With this ‘S theory’ the partition is obtained in order n (in terms of memory space and elementary operations), n being the number of elements to classify.
A fuzzy interpretation for an ecological site classification case
Authors: El‐Shishiny Hisham , Ghabbour Samir I. 
Published: May 2007

AbstractA case study is presented in which four sites in the Jebel Marra highlands in western Sudan and four sites from the Erkowit plateau in eastern Sudan are classified according to a list of collected soil fauna taxa and their densities. The fuzzy isodata algorithm was used satisfactorily to classify the sites in accordance with a biologist's observations. Comparison of the fuzzy classification with the results of some ordination methods is also given.
Inference in lognormal multidimensional diffusion processes with exogenous factors: Application to modelling in economics
Authors: Gutiérrez R. , Angulo J. M. , González A. , Pérez R. 
Published: May 2007

AbstractThe multidimensional lognormal diffusion process with exogenous factors is treated using the Kolmogorov equations, and the mean vector and covariance matrix are estimated using discrete sampling by the maximum‐likelihood method. Also, this process is constructed as a solution of a multidimensional stochastic differential equation, and an estimation is made through the maximum‐likelihood method to infer the parameters of the exogenous factors, this time using continuous sampling. Finally, a test for a hypothesis based on these parameters is constructed.
Mixture decomposition via the simulated annealing algorithm
Authors: Ingrassia S. 
Published: May 2007

AbstractThis paper presents the problem of the evaluation of the maximum likelihood estimator, when the likelihood function has multiple maxima, using the stochastic algorithm called ‘simulated annealing’. Analysis of the particular case of the decomposition of a mixture of five univariate normal distributions shows the properties of this methodology with respect to the E—M algorithm. The results are compared considering some distance measures between the estimated distribution functions and the true one.
Considerations on modelling the market for softwood lumber in the United States
Authors: Uri Noel D. , Boyd Roy 
Published: May 2007

AbstractThe analysis in this paper looks at two important elements in modelling the market for timber in the United States. First, the issue of directional causality between price and quantity and its implications in a modelling effort is investigated. Second, the extent of the geographic market for timber is discussed and a method of detecting it is suggested. The method for detecting the extent of the geographical market is tractable and can be applied in a straightforward way. Both considerations are applied to the softwood lumber market in the United States.
Discriminant versus rough sets approach to vague data analysis
Authors: Krusińska Ewa , Slowinski Roman , Stefanowski Jerzy 
Published: May 2007

AbstractThis paper presents a comparative study of the use of two different methods of data analysis on a common set of data. The first is a method based on rough sets theory and the second is the location model method from the field of discriminant analysis. To investigate the comparative performance of these methods, a set of real medical data has been used. The data considered are of both discrete and continuous character. During the comparison, particular attention is paid to data reduction and to the derivation of decision rules and classification functions from the reduced set.
Complexity models in financial markets
Authors: Landes Thomas , Loistl Otto 
Published: May 2007

AbstractIn this approach, the complexity of the self‐organizing microstructure of the stock exchange is explicitly taken into consideration: the process of offers and trades as well as the adjustment of individual expectations are modelled with help of a (stochastic) jump process. Its abilities are illustrated by modelling the continuous quotations of asset prices at an auction type stock exchange. The functional form of the transition (hazard) rates is chosen to reflect the individual preferences and expectations as well as the economic environment. The model is described in detail and examples of Monte Carlo simulation results are presented.
On a stochastic model for particle sedimentation in fluids
Authors: Hesse C. H. 
Published: May 2007

AbstractThe engineering sciences have long been interested in models describing the settling (or sedimentation) of particle ensembles in viscous fluids. From a theoretical point of view, sedimentation constitutes a two phase many‐body phenomenon with complex interaction and as such has proved to be quite inaccessible to modelling attempts with relevance in applications. A stochastic model was introduced by Pickard and Tory in 1977 and was subsequently revised. In this paper we expand and refine the stochastic model and present a satisfactory model‐fitting procedure and parameter estimators based on transit times of sedimenting particles.
Manufacturing cell formation under capacity constraints
Authors: Xie Xiaolan 
Published: May 2007

AbstractThe cell formation problem is addressed for a manufacturing system containing groups of identical machines. Various part types are produced. The manufacture of a part requires a sequence of operations and each operation can be performed by any machine of a given type. The cell formation problem consists in grouping machines into cells and assigning operations to machines so as to minimize the intercell traffic while satisfying machine capacity constraints and other technical constraints. An important feature of this problem is that machines of the same type may be assigned to different cells. Since the problem is NP‐hard, heuristic solutions are proposed and numerical experiences show that the proposed algorithms lead to near‐optimal solutions.
Stochastic dispersive transport: An excursion from statistical physics to automated production line design
Authors: Hongler M.‐O. 
Published: May 2007

AbstractBoth the sediment transport dynamics and the population level of a buffer in automated production line systems can be described by the same class of stochastic differential equations. The ubiquitous noise is generated by continuous time Markov chains. The probability densities which describe the dynamics are governed by high‐order hyperbolic systems of partial differential equations. While this hyperbolic nature clearly exhibits a non‐diffusive character of the processes (diffusion would imply a parabolic evolution of the probability densities), we nevertheless can use a central limit theorem which holds for large‐time regimes. This enables analytical estimations of the time evolution of the moments of these processes. Particular emphasis is devoted to non‐Markovian, dichotomous alternating renewal processes, which enter directly into the description of the applications presented.
Estimating a linear functional relationship under linear constraints for errors
Authors: Lappi Juha , Sievänen Risto 
Published: May 2007

AbstractMaximum likelihood estimates for parameters in a linear functional relationship are derived when the errors are also linearly related for each observation. This is approximately the case, for example, when both variables are smooth functions of time and their values are recorded as an experimental unit reaches a certain state. This kind of model specification was needed to describe how the timing of growth cessation of trees depends on night length and temperature sum. If the slope in the constraint equation for errors varies, then an iterative estimation procedure is needed. The estimation method is extended for a two‐phase linear model.
Estimating household purchase rates for consumer nondurable goods
Authors: Jain Dipak C. , Vilcassim Naufel J. 
Published: May 2007

AbstractUnderstanding the purchase rates of households for frequently purchased packaged goods is an important element in developing effective marketing strategies. Previous researchers have attempted to estimate these rates by assuming that the time between purchases is a random variable that follows some common parametric probability distribution such as the exponential or Weibull distribution. Recent research has shown that for many frequently purchased packaged goods, the interpurchase times cannot be adequately described by these commonly used probability distributions. In this study we demonstrate how household purchase rates can be estimated in a robust manner using a generalized semiparametric approach that obviates the need for specifying a parametric form for the distribution of interpurchase times. The motivation being that often there is no theory of household purchase behaviour that specifiesa priorithe probability distribution underlying the interpurchase times. Our empirical results indicate that, for the data analysed, the household purchase rates exhibit a regular pattern that cannot be recovered by probability distributions often used in previous research. Further, marketing actions taken by sellers do indeed influence household purchase behaviour.
Parameter estimation in multi–component systems with failure interaction
Authors: Murthy D. N. P. , Wilson R. J. 
Published: May 2007

AbstractIn multi–component systems, failure of a component often affects one or more of the remaining components of the system. This type of interaction between components is called &&num;145;failure interaction&&num;146;. In this paper we consider two failure interaction models and study the problem of estimating the parameters of these models.
A reliability application of a mixture of inverse gaussian distributions
Authors: Smith Charles E. , Lánský Petr 
Published: May 2007

AbstractA mixture of inverse Gaussian distributions (IGDs) is examined as a model for the lifetime of components. The components differ in one of three ways: in their initial quality, rate of wear, or variability of wear. These three cases are well represented by the parameters of the IGD model. The mechanistic interpretation of the IGD as the first passage time of Brownian motion with positive drift is adopted. The parameters considered are either dichotomous or continuous random variables. Parameter estimation is also examined for these two cases. The model seems to be most appropriate when the single IGD model fails due to heterogeneity of the initial component quality.
A systems approach to the calibration of deterministic dynamic nonlinear simultaneous equation models with incomplete data
Authors: Hartley Michael J. 
Published: May 2007

AbstractThis paper develops an interactive three–stage systems approach for the calibration of the structural parameters and missing data within a deterministic, dynamic non–linear simultaneous equations model under arbitrary configurations of incomplete data. In Stage One, we minimize a quadratic loss function in the differences between the actual endogenous variables and the predicted solution values, relative to any feasible choice of the structural parameters. Missing exogenous variables and initial endogenous variables are treated as additional parameters to be calibrated; whereas missing current endogenous variables are treated by the missing data updating condition, in which the current solution values iteratively and sequentially replace those absent. Stage One may or may not lead to unique calibrations of the structural parameters—a fact that can be monitoreda posterioriusing singular value decompositions of the relevant Jacobian matrix. If not, there is an equivalence class of parameter values, all of which result in the same loss function value. If Stage Two is necessary, we attempt to exploit the non–linearity and simultaneity of the structural system to extract further information about the parameters from the same database, by minimizing the distance between the restricted and unrestricted reduced forms, while constraining the parameters also to lie within the Stage One equivalence class. This requires the use of higher–order numerical derivatives, and probably restricts its use in all but the simplest of cases to the next generation of supercomputers with massive numbers of parallel processors and much larger word–sizes. In Stage Three, various methods by which the original structural model can be simplified, given a non–unique Stage One calibration, are entertained.
Joint availability of systems modelled by finite semi–markov processes
Authors: Csenki A. 
Published: May 2007

AbstractConsider a repairable system at the time instants t and t + x, where t, x ≥0. The joint availability of the system at these time instants is defined as the probability of the system being functional in both t and t + x. A set of integral equations is derived for the joint availability of a system modelled by a finite semi–Markov process. The result is applied to the semi–Markov model of a two–unit system with sequential preventive maintenance. The method used for the numerical solution of the resulting system of integral equations is a two–point trapezoidal rule. The system of implementation is the matrix computation package MATLAB on the Apple Macintosh SE/30. The numerical results obtained by this method are shown to be in good agreement with those from simulation.