bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compatible simultaneous lower confidence bounds for the Holm procedure and other Bonferroni‐based closed tests
Authors: Strassburger Klaus , Bretz Frank 
Published: July 2008

AbstractWe consider the problem of simultaneously testing multiple one‐sided null hypotheses. Single‐step procedures, such as the Bonferroni test, are characterized by the fact that the rejection or non‐rejection of a null hypothesis does not take the decision for any other hypothesis into account. For stepwise test procedures, such as the Holm procedure, the rejection or non‐rejection of a null hypothesis may depend on the decision of other hypotheses. It is well known that stepwise test procedures are by construction more powerful than their single‐step counterparts. This power advantage, however, comes only at the cost of increased difficulties in constructing compatible simultaneous confidence intervals for the parameters of interest. For example, such simultaneous confidence intervals are easily obtained for the Bonferroni method, but surprisingly hard to derive for the Holm procedure. In this paper, we discuss the inherent problems and show that ad hoc solutions used in practice typically do not control the pre‐specified simultaneous confidence level. Instead, we derive simultaneous confidence intervals that are compatible with a certain class of closed test procedures using weighted Bonferroni tests for each intersection hypothesis. The class of multiple test procedures covered in this paper includes gatekeeping procedures based on Bonferroni adjustments, fixed sequence procedures, the simple weighted or unweighted Bonferroni procedure by Holm and the fallback procedure. We illustrate the results with a numerical example. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of longitudinal data to evaluate a policy change
Authors: French Benjamin , Heagerty Patrick J. 
Published: July 2008

AbstractLongitudinal data analysis methods are powerful tools for exploring scientific questions regarding change and are well suited to evaluate the impact of a new policy. However, there are challenging aspects of policy change data that require consideration, such as defining comparison groups, separating the effect of time from that of the policy, and accounting for heterogeneity in the policy effect. We compare currently available methods to evaluate a policy change and illustrate issues specific to a policy change analysis via a case study of laws that eliminate gun‐use restrictions (shall‐issue laws) and firearm‐related homicide. We obtain homicide rate ratios estimating the effect of enacting a shall‐issue law, which vary between 0.903 and 1.101. We conclude that in a policy change analysis it is essential to select a mean model that most accurately characterizes the anticipated effect of the policy intervention, thoroughly model temporal trends, and select methods that accommodate unit‐specific policy effects. We also conclude that several longitudinal data analysis methods are useful to evaluate a policy change, but not all may be appropriate in certain contexts. Analysts must carefully decide which methods are appropriate for their application and must be aware of the differences between methods to select a procedure that generates valid inference. Copyright © 2008 John Wiley & Sons, Ltd.
Multi‐state analysis of cognitive ability data: A piecewise‐constant model and a Weibull model
Authors: van den Hout Ardo , Matthews Fiona E. 
Published: July 2008

AbstractLongitudinal data can be used to estimate transition intensities between healthy and unhealthy states prior to death. When health is defined with respect to cognitive ability during old age, the trajectory of performance is either static or downward. An illness–death model is presented where the intensity of a transition is allowed to change over time by using a piecewise‐constant model or by using a Weibull model. Observed improvement of cognitive ability is modelled as misclassification. The methodology is extended to estimate life expectancy with and without cognitive impairment. The measurement of cognitive ability is important as it is an important predictor of future need for care. The models can help to understand how cognitive decline develops over time and which factors play a role. The methods are illustrated using data from the Medical Research Council Cognitive Function and Ageing Study in the U.K. (1991–2005). Copyright © 2008 John Wiley & Sons, Ltd.
Comparisons between ITT and treatment emergent adverse event analyses
Authors: Quan Hui , Sun Qiankun , Zhang Ji , Shih Weichung J. 
Published: July 2008

AbstractDifferent from the use of intention‐to‐treat (ITT) analysis for efficacy evaluation, many pharmaceutical companies currently use treatment emergent (TE) analysis for adverse event (AE) safety analysis. In the TE analysis, study period and AEs occurring after a pre‐specified post‐treatment window will not be included. One consideration for using the TE AE analysis is that including substantial off‐drug period and events in the analysis may dilute the power for detecting safety signals especially if after discontinuation residual treatment effect diminishes quickly. We perform quantitative analyses to compare the unbiasedness and power of the ITT and TE AE analyses under several different settings and metrics (difference in rates and relative risk). Results show that unbiasedness and power are not always in the same direction. The choice of an approach for a particular trial should depend on the focus of the analysis. A data example is used to illustrate these points. Copyright © 2008 John Wiley & Sons, Ltd.
Bayesian transformation cure frailty models with multivariate failure time data
Authors: Yin Guosheng 
Published: July 2008

AbstractWe propose a class of transformation cure frailty models to accommodate a survival fraction in multivariate failure time data. Established through a general power transformation, this family of cure frailty models includes the proportional hazards and the proportional odds modeling structures as two special cases. Within the Bayesian paradigm, we obtain the joint posterior distribution and the corresponding full conditional distributions of the model parameters for the implementation of Gibbs sampling. Model selection is based on the conditional predictive ordinate statistic and deviance information criterion. As an illustration, we apply the proposed method to a real data set from dentistry. Copyright © 2008 John Wiley & Sons, Ltd.
Performance implications of delayed competitive responses: evidence from the U.S. retail industry
Authors: Boyd Jens L. , Bresser Rudi K. F. 
Published: July 2008

AbstractThe timing of competitive actions and responses is a key management concern that has important performance consequences. This study focuses on the timing and consequences of competitive responses. Theory predicts a negative linear relationship between response delay and responder performance mirrored by an opposing positive linear relationship between response delay and first mover performance. In contrast, our study suggests that response delay has a curvilinear relationship with responder performance, and a linear relationship with first mover performance. We test our propositions using retail industry data and discuss the implications. Copyright © 2008 John Wiley & Sons, Ltd.
Extended firewall for regression testing: an experience report
Authors: White Lee , Jaber Khaled , Robinson Brian , Rajlich Václav 
Published: July 2008

AbstractTesting firewalls have proven to be a useful approach for regression testing in both functional and object‐oriented software. They involve only the modules that are closely related to the changed modules. They lead to substantially reduced regression tests but still are very effective in detecting regression faults. This paper investigates situations when data‐flow paths are longer, and the testing of modules and components only one level away from the changed elements may not detect certain regression faults; an extended firewall considers these longer data paths. We report empirical studies that show the degree to which an extended firewall detected more faults, and how much more testing was required to achieve this increased detection. Copyright © 2008 John Wiley & Sons, Ltd.
Die zweite Geo‐Geum‐Brücke in Südkorea – Schrägkabelbrücke und Vorlandbrücke für Straßenverkehr mit Verbundfachwerkträger
Authors: Hopf Siegfried , Patsch Armin 
Published: July 2008

AbstractDie zweite Geo Geum Grand Bridge wird Teil der festen Verbindung zwischen Geo Geum Island und der Koreanischen Halbinsel sein (Bild 1). Diese Hochbrücke setzt sich zusammen aus einer 912 m langen Vorlandbrücke und einer 1116 m langen Schrägseilbrücke mit einer Hauptspannweite von 480 m. Die Vorlandbrücke ist ein Durchlaufträger mit typischen Spannweiten von 120 m. Der Überbau beider Brücken ist ein Verbundfachwerkträger mit Betonfahrbahnplatte im Obergurt für 2‐spurigen Straßenverkehr und einem unten liegenden Fußgänger‐ und Radweg. Die Entwurfsgrundlagen für diese Brücke waren: Funktionalität als Straßenbrücke, ein innovativer Entwurf und gute Einbindung in die Umgebung. Die gebündelte Fächerform der in der Mittelebene angeordneten Schrägkabel gibt dieser Brücke ein besonderes und einzigartiges Aussehen.
Versuche an genieteten Brückenlängsträgern – Statisches Verhalten, Ermüdungsfestigkeit und Rissausbreitung
Authors: Taras Andreas , Greiner Richard 
Published: July 2008

AbstractDie Bewertung der Tragfähigkeit und Restlebensdauer bestehender Eisenbahn‐ und Straßenbrücken gewinnt in den letzten Jahren immer mehr an Bedeutung. Bei der Ausarbeitung der Richtlinie ONR 24008 stellte sich daher erneut die Frage nach der Festigkeit genieteter Bauteile älterer Stahlbrücken. Im Laufe dieses Forschungsvorhabens wurden am Labor für Konstruktiven Ingenieurbau (LKI) in Zusammenarbeit mit dem Institut für Stahlbau und Flächentragwerke der Technischen Universität Graz statische Versuche und Ermüdungsversuche an genieteten Bauteilen aus einem abgetragenen Brückentragwerk desÖBB‐Netzes durchgeführt. Die Auswertung dieser Versuche gab zusätzlichen Einblick in das Tragverhalten zusammengesetzter genieteter Bauteile, besonders in das Rissfortschrittsverhalten bei Ermüdung.
Durchknöpftragfähigkeit der Verbindungen von Aluminiumtrapezprofilen und Aluminiumwellprofilen bei Befestigung im anliegenden Gurt
Authors: Misiek Thomas , Saal Helmut 
Published: July 2008

AbstractDas Durchknöpfversagen von Verbindungen bei Aluminiumtrapezprofilen und Aluminiumwellprofilen unterscheidet sich vom Durchknöpfversagen vergleichbarer Verbindungen bei Stahlprofilen. Die Gründe für diese Unterschiede und die sich daraus ergebenden Konsequenzen werden hier erläutert. Auf Grundlage der beobachteten Versagensmodi und einiger grundsätzlicher Aspekte wird ein neuer Ansatz zur rechnerischen Ermittlung der Durchknöpftragfähigkeit von Verbindungen entwickelt, der gegenüber DIN 18807‐6 ohne einen Verlust an Sicherheit die Genauigkeit der Vorhersage der Tragfähigkeit signifikant verbessert.
Auswirkung von monotoner und zyklischer Belastung auf die Undichtheit eines Tankbodenecks
Authors: Wasicek Manfred , Fischer Franz Dieter , Kolednik Otmar 
Published: July 2008

AbstractDas geschweißte Tankbodeneck eines vertikalen Lagertanks ist eine der gefährdetsten Stellen des Tanks. Füllen und Entleeren oder Erdbeben führen durch das Abheben des Tankbodenecks zu hohen plastischen Dehnungen im Schweißnahtbereich des Tankbodenecks. Einbrandkerben am Übergang von der Kehlnaht zum Grundmaterial verursachen Risse im Kerbgrund, die wachstumsfähig sind und die Undichtheit des Tanks zur Folge haben. Ein geo‐metrisch und materiell nichtlineares Finite‐Elemente‐Modell für zwei typische Tankgeometrien (hoher und breiter Tank) wird vorgestellt und mit der Ermittlung der Risstriebkraft (J‐Integral) für Risse im Grund von gegebenen Kerben kombiniert. Bei monotoner Belastung werden die berechneten J‐Integrale mit experimentell ermittelten J‐Integral‐Rissverlängerungswerten verglichen und kritische Kerb‐ und Risstiefen festgestellt. Bei zyklischer Belastung wird ein Low‐Cycle‐Fatigue‐Konzept für einen wachstumsfähigen Riss im Kerbgrund vorgestellt. Zusätzlich wird ein Schädigungsindikator aktiviert. Die Ergebnisse werden zu einer Aussage über die mögliche Undichtheit infolge intensiver plastischer Verformung in Verbindung mit Risswachstum zusammengefasst.
Systems engineering leading indicators for assessing program and technical effectiveness
Authors: Rhodes Donna H. , Valerdi Ricardo , Roedler Garry J. 
Published: July 2008

AbstractThis paper discusses a 3‐year initiative to transform classical systems engineering (SE) measures into leading indicators, including the resulting guidance information that has been developed and future research directions. Systems engineering leading indicators are measures for evaluating the effectiveness of the systems engineering activities on a program in a manner that provides information about impacts that are likely to affect the system or program performance objectives. A leading indicator may be an individual measure, or collection of measures, that is predictive of future system performance before the performance is realized. Contrary to simple status oriented measures typically used on most projects, leading indicators are intended to provide insight into the probable future state, allowing projects to improve the management and performance of complex programs before problems arise. This paper discusses the motivations and collaborative development of the SE leading indicators. It defines the leading indicator construct, introduces the initial set of 13 indicators, and provides guidance for implementation, analysis, and interpretation of these indicators. The initial set of indicators, developed through a collaboration of industry, government, and academia, has recently undergone validation through pilot studies and surveys. This work serves as a foundation for industry implementation and for further research to improve and expand the set of indicators, including development of a better understanding of how to best implement and use the leading indicators in a given program context. © 2008 Wiley Periodicals, Inc. Syst Eng
Umbilical venous blood flow measurement: accuracy and reproducibility
Authors: Figueras F. , Fernández S. , Hernández‐Andrade E. , Gratacós E. 
Published: July 2008

AbstractUmbilical venous blood flow could be considered a direct and physiological measurement of vascular placental function, representing the quantity of oxygen and nutrients reaching the fetus. The advent of high‐technology ultrasound and pulsed Doppler has overcome some of the limitations of early studies. Indeed, Doppler measurement of umbilical venous blood flow has been found to be accurate when compared with several gold standards for in‐vivo flow calculation. Nevertheless, small errors in volume flow components, the vessel area and the mean velocity, result in large errors in the calculation of volume flow. Therefore, technique standardization is of paramount importance. Validation studies in animal models have demonstrated accurate venous blood flow measurements by estimating the vessel's cross‐sectional area from perpendicular views of longitudinal sections of free‐floating portions of the cord. On the other hand, estimation of the mean velocity from the maximum velocity, rather than using the intensity‐weighted mean velocity, is less software‐dependent and more clearly defined, yielding estimates with more predictable and systematic errors. By adhering to stringent methodological recommendations, umbilical venous blood flow calculation has moderate to good intra‐ and interobserver reproducibility. Having been found to be accurate and reproducible, further studies are required to establish the clinical value of umbilical vein flow measurement. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Performance evaluation of the MAC protocol in IEEE 802.16 systems with data and VoiP traffic scheduling
Authors: Fantacci Romano , Tarchi Daniele , Bardazzi Marco 
Published: July 2008

AbstractIn the last few years, the metropolitan area networks (MAN) have increased their popularity and attracted the interest of the most important research groups all over the world. Among several standards, IEEE 802.16 has taken a relevant role providing high data rate in a big covering range with low implementation costs and multi‐traffic communications. The IEEE 802.16 networks can have a pre‐defined structure, with a central base station (BS) covering a cell in which a variable number of subscriber stations (SSs) can work. This paper deals with the proposal of a quality of service (QoS) driven scheduling algorithm to be used in an IEEE 802.16 network where different traffic types coexist. In particular, the paper mainly focuses on best effort data and VoIP communications, by proposing a scheduling technique that allows an efficient resource management of both traffic types by considering their specific QoS flavor. The performance evaluation has been carried out by considering both the phases of contention and packet scheduling, by means of a theoretical approach and computer simulations. Numerical results show the performance of the proposed algorithm by focusing on a scenario where the BS schedules the best effort and VoIP traffics of several SSs. Copyright © 2008 John Wiley & Sons, Ltd.
Target localization and tracking in noisy binary sensor networks with known spatial topology
Authors: Xiangqian Liu , Gang Zhao , Xiaoli Ma 
Published: July 2008

AbstractTarget localization and tracking are two of the critical tasks of sensor networks in many applications. Conventional localization and tracking techniques developed for wireless systems that rely on direction‐of‐arrival (DOA) or time‐of‐arrival (TOA) information are not suitable for low‐power sensors with limited computation and communication capabilities. In this paper, we propose a low‐complexity and energy‐efficient method for target localization and tracking in noisy binary sensor networks, where the sensors can only perform binary detection, and the physical links are characterized by additive white Gaussian noise (AWGN) channels. The proposed method is based on known spatial topology. An efficient wake‐up strategy is used to activate a particular group of sensors for cooperative localization and tracking. We analyze the localization error probability and tracking miss probability in the presence of prediction errors. Simulation results validate the theoretic analysis and demonstrate the effectiveness of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd.
Coverage and connectivity in three‐dimensional underwater sensor networks
Authors: Alam S. M. Nazrul , Haas Zygmunt J. 
Published: July 2008

AbstractUnlike a terrestrial network, an underwater sensor network can have significant height which makes it a three‐dimensional network. There are many important sensor network design problems where the physical dimensionality of the network plays a significant role. One such problem is determining how to deploy minimum number of sensor nodes so that all points inside the network is within the sensing range of at least one sensor and all sensor nodes can communicate with each other, possibly over a multi‐hop path. The solution to this problem depends on the ratio of the communication range and the sensing range of each sensor. Under sphere‐based communication and sensing model, placing a node at the center of each virtual cell created by truncated octahedron‐based tessellation solves this problem when this ratio is greater than 1.7889. However, for smaller values of this ratio, the solution depends on how much communication redundancy the network needs. We provide solutions for both limited and full communication redundancy requirements. Copyright © 2008 John Wiley & Sons, Ltd.
Mitochondrial inheritance and fermentative : oxidative balance in hybrids between Saccharomyces cerevisiae and Saccharomyces uvarum
Authors: Solieri Lisa , Antúnez Oreto , Pérez‐Ortín Josè Enrique , Barrio Eladio , Giudici Paolo 
Published: July 2008

AbstractBreeding between Saccharomyces species is a useful tool for obtaining improved wine yeast strains, combining fermentative features of parental species. In this work, 25 artificial Saccharomyces cerevisiae × Saccharomyces uvarum hybrids were constructed by spore conjugation. A multi‐locus PCR–restriction fragment length polymorphism (PCR–RFLP) analysis, targeting six nuclear gene markers and the ribosomal region including the 5.8S rRNA gene and the two internal transcribed spacers, showed that the hybrid genome is the result of two chromosome sets, one coming from S. cerevisiae and the other from S. uvarum. Mitochondrial DNA (mtDNA) typing showed uniparental inheritance in all hybrids. Furthermore, sibling hybrids, obtained by repeated crosses between the same parental strains, showed the same mtDNA, suggesting that the mitochondrial transmission is not stochastic or species‐specific, but dependent on the parental strains. Finally four hybrids, two of which with S. cerevisiae mtDNA and two with S. uvarum mtDNA, were subjected to transcriptome analysis. Our results showed that the hybrids bearing S. cerevisiae mtDNA exhibited less expression of genes involved in glycolysis/fermentation pathways and in hexose transport compared to hybrids with S. uvarum mtDNA. Respiration assay confirmed the increased respiratory activity of hybrids with the S. cerevisiae mtDNA genome. These findings suggest that mtDNA type and fermentative : respiratory performances are correlated in S. cerevisiae × S. uvarum hybrids and the mtDNA type is an important trait for constructing new improved hybrids for winemaking. Copyright © 2008 John Wiley & Sons, Ltd.
Relatedness of medically important strains of Saccharomyces cerevisiae as revealed by phylogenetics and metabolomics
Authors: MacKenzie Donald A. , Defernez Marianne , Dunn Warwick B. , Brown Marie , Fuller Linda J. , de Herrera Santiago R. M. Seco , Günther Andreas , James Steve A. , Eagles John , Philo Mark , Goodacre Royston , Roberts Ian N. 
Published: July 2008

AbstractTen medically important Saccharomyces strains, comprising six clinical isolates of Saccharomyces cerevisiae and four probiotic strains of Saccharomyces boulardii, were characterized at the genetic and metabolic level and compared with non‐medical, commercial yeast strains used in baking and wine‐making. Strains were compared by genetic fingerprinting using amplified fragment length polymorphism (AFLP) analysis, by ribosomal DNA ITS1 sequencing and by metabolic footprinting using both direct injection mass spectrometry (DIMS) and gas chromatography–time of flight–mass spectrometry (GC–ToF–MS). Overall, the clinical isolates fell into different groupings when compared with the non‐medical strains, with good but not perfect correlation amongst strains at both the genetic and metabolic levels. Probiotic strains of S. boulardii that are used therapeutically to treat human gastro‐intestinal tract disorders showed tight clustering both genetically and metabolically. Metabolomics was found to be of value both as a taxonomic tool and as a means to investigate anomalous links between genotype and phenotype. Key discriminatory metabolites were identified when comparing the three main groups of clinical, probiotic and non‐medical strains and included molecules such as trehalose, myo‐inositol, lactic acid, fumaric acid and glycerol 3‐phosphate. This study confirmed the link between a subset of clinical isolates and baking or probiotic strains but also highlighted that in general the clinical strains were more diverse at both the genomic and metabolic levels. Copyright © 2008 John Wiley & Sons, Ltd.