bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generating highly nonlinear resilient Boolean functions resistance against algebraic and fast algebraic attacks
Authors: Yang Jun‐Po , Zhang Wei‐Guo 
Published: September 2014

ABSTRACTBoolean functions play an important role in the design of stream ciphers. In this paper, a simulated annealing algorithm is designed to obtain Boolean functions satisfying all the needed criteria: high nonlinearity, 1‐resiliency, optimal algebraic degree, optimal (or suboptimal) algebraic immunity, and good immunity to fast algebraic attacks. These functions provide a good trade‐off among the criteria to resist the known cryptanalytic techniques. Copyright © 2014 John Wiley & Sons, Ltd.
Numerische Simulation von Verbundstützen im Brandfall
Authors: Mensinger Martin , Hahn Andreas , Zhang Canghai 
Published: September 2014

AbstractDie weltweit verbreiteten, und teilweise auf recht vereinfachten Ansätzen basierenden Bemessungsverfahren für Verbundstützen im Brandfall, geben Anlass zu einem genauen Vergleich an konkreten Beispielen. Im Folgenden wird auf die numerische Untersuchung einer Verbundstütze mit ANSYS Workbench [1] eingegangen. Die Validierung stützt sich dabei hauptsächlich auf externe Versuchsergebnisse von Romero und Espinos [12]. Abschließend werden die numerischen Ergebnisse des kalibrierten FE‐Modells mit Handrechenergebnissen auf Basis allgemein gültiger Verfahren und Normen, wie z. B. die hierzulande gültige DIN EN 1994‐1‐2 [16], verglichen.Numerical simulation of composite columns in case of fire. The design procedures used worldwide for composite columns in case of fire with partially simplified approaches provide impetus to an exact comparison on tangible examples. The numerical analysis of a composite column with ANSYS Workbench [1] is described in detail in this paper. The validation mainly relies on external test results of Romero and Espinos [12]. Finally, the numerical results are compared with generally applicable procedures, such as in DIN EN 1994‐1‐2 [16] which is the currently valid standard in Germany.
Robustness of steel‐concrete flooring systems – An experimental assessment
Authors: Zandonini Riccardo , Baldassino Nadia , Freddi Fabio 
Published: September 2014

AbstractRecently, the interest in the mitigation of the damages caused by accidental events increased significantly. The knowledge of loads transfer mechanisms from the damaged to the undamaged part of the structure is the key for developing adequate design strategies. Despite the potential important role of flooring systems, research of this subject is still limited. A European Research Project aims at achieving an insight into the case of steel‐concrete composite frames with solid concrete slabs. Two geometrically different 3D composite sub‐frames are subjected to the loss of an internal column. The sub‐frames are a full‐scale portion of 5 stories 3D frames. Equivalence between the sub‐frames and the full‐frames required a series of careful numerical analysis, which enabled definition of the boundary restraints of the specimens and of the loading sequence in the test. The present paper illustrates these preparatory studies and gives some preliminary information about the outcomes of the first test.Robustheit von Verbunddecken – Eine experimentelle Bewertung. In den letzten Jahren ist das Interesse an der Begrenzung von durch Unfälle bedingten Schäden gewachsen. Die Kenntnis der Lastübertragungsmechanismen von den beschädigten zu den unbeschädigten Tragwerksteilen ist der Schlüssel zur Entwicklung geeigneter Bemessungskonzepte. Trotz der wichtigen Erkenntnis über den Einfluss der Deckenwirkung stehen keine ausreichenden Forschungsergebnisse zu dieser Thematik zur Verfügung. In einem europäischen Forschungsprojekt werden Tragsysteme aus Verbundrahmen mit Stahlbetonplatten untersucht. Dabei werden zwei geometrisch unterschiedliche 3D‐Versuchsrahmen auf die extreme Annahme eines Stützenausfalls untersucht. Die Versuchsrahmen sind vollmaßstäblich ausgebildet und repräsentieren den unteren Teil des Rahmentragwerks eines fünfstöckigen Gebäudes. Die Auflagerbedingungen und die Belastungssequenzen der Versuchsrahmen wurden durch zahlreiche numerische Untersuchungen ermittelt, um denjenigen des Rahmensystems vom Gebäude zu entsprechen. Der vorliegende Beitrag zeigt diese Vorstudien und berichtet über einige experimentelle Ergebnisse aus dem ersten Versuch.
Gestaltung und Berechnung von Stahlkonstruktionen für Nachlaufinstallationen von Tunnelbohrmaschinen
Authors: Baumann Hans Jörg , Blümel Steffen , Kälin Andreas 
Published: September 2014

AbstractNachlaufinstallationen von Tunnelbohrmaschinen werden grundsätzlich aus Stahl hergestellt. Die Berechnung und konstruktive Gestaltung erfolgt analog den Konstruktionen des Stahlhochbaus auf der Grundlage der EN 1993 oder entsprechender nationaler Normenwerke. Bei der Planung derartiger temporärer und bewegter Bauwerke sind jedoch eine Vielzahl von spezifischen konstruktiven Anforderungen aus der Nutzung und diverse statische Anforderungen hinsichtlich der Beanspruchung sowie der Modellbildung zu berücksichtigen. In diesem Aufsatz werden einige dieser Anforderungen vorgestellt und Lösungsvarianten für die Ausbildung des Tragsystems aufgezeigt.Design and analysis of steel structures for back‐up installations of tunnel boring machines. Back‐up installations of tunnel boring machines are generally made of steel structures. The analysis and structural design is analogous to the steel building constructions and has to be done on the basis of EN 1993 or equivalent national standards. However, for such temporary and moving structures a variety of specific design requirements due to use and various static requirements concerning loads and system modelling have to be taken into account. In this paper, some of these requirements as well as solutions for the design will be presented.
Zur Nachhaltigkeit von Stahl‐ und Verbundkonstruktionen bei Büro‐ und Verwaltungsgebäuden – Tragkonstruktionen (Teil 2)
Authors: Stroetmann Richard , Podgorski Christine 
Published: September 2014

AbstractDer folgende Beitrag zur Nachhaltigkeit von Tragkonstruktionen für Büro‐ und Verwaltungsgebäude ist eine Fortsetzung des Aufsatzes [1]. Dort wurden zunächst eine Übersicht über das AIF‐FOSTA‐Projekt P881 gegeben und die Objektanforderungen an die Tragkonstruktionen sowie Deckensysteme in Stahl‐ und Verbundbauweise beschrieben. Nach einer Übersicht zur Normungssituation und Bewertungssystemen wurde die im Forschungsprojekt angewendete Methodik zur Beurteilung der ökologischen und ökonomischen Qualität von Tragkonstruktionen erläutert. Ferner ging der Beitrag auf Untersuchungen zur Optimierung von Deckensystemen ein. Gegenstand des hier vorliegenden zweiten Teils ist die Querschnittswahl und Bemessung der Gebäudestützen für ständige und vorübergehende Bemessungssituationen sowie für den Brandfall unter Nachhaltigkeitskriterien. Anschließend werden die Ergebnisse aus Parameterstudien zur Optimierung von Tragsystemen mit Unterzugsdecken vorgestellt, in denen die Decken, Trägersysteme und Stützen einbezogen wurden. In einem noch folgenden Beitrag werden dann Flachdeckensysteme und die Anschlüsse thematisiert.Sustainability of steel and composite structures of office and administration buildings – Structural systems (part 2). The following paper on the sustainability of structural systems of office and administration buildings is a sequel of the article [1]. In that paper, an overview on the AIF FOSTA Project P881 was given and the requirements resulting from the building and structural design as well as slab systems in steel and composite construction were described. After an overview on the standardization situation and assessment systems, the methods used in the research project to assess the environmental and economic performance of structural systems were explained. In addition, the paper discussed studies on the optimization of slab systems. The choice of the cross‐section and the dimensioning of the building columns for persistent and transient design situations as well as for the case of fire considering sustainability criteria are the subject of the second part on the structural systems. Following this, the results of parametric studies to identify the optimal structural systems with downstand beams are presented, in which the slabs, beam systems and columns are included. Slim floor systems and connections are addressed in a remaining paper.
Sleep deprivation induces differential morphological changes in the hippocampus and prefrontal cortex in young and old rats
Authors: Acosta‐peña Eva , Camacho‐Abrego Israel , Melgarejo‐Gutiérrez Montserrat , Flores Gonzalo , Drucker‐Colín René , García‐García Fabio 
Published: September 2014

ABSTRACTSleep is a fundamental state necessary for maintenance of physical and neurological homeostasis throughout life. Several studies regarding the functions of sleep have been focused on effects of sleep deprivation on synaptic plasticity at a molecular and electrophysiological level, and only a few studies have studied sleep function from a structural perspective. Moreover, during normal aging, sleep architecture displays some changes that could affect normal development in the elderly. In this study, using a Golgi‐Cox staining followed by Sholl analysis, we evaluate the effects of 24 h of total sleep deprivation on neuronal morphology of pyramidal neurons from Layer III of the prefrontal cortex (PFC) and the dorsal hippocampal CA1 region from male Wistar rats at two different ages (3 and 22 months). We found no differences in total dendritic length and branching length in both analyzed regions after sleep deprivation. Spine density was reduced in the CA1 of young‐adults, and interestingly, sleep deprivation increased spine density in PFC of aged animals. Taken together, our results show that 24 h of total sleep deprivation have different effects on synaptic plasticity and could play a beneficial role in cognition during aging. Synapse 69:15–25, 2015. © 2014 Wiley Periodicals, Inc.
True Reproducibility of UltraSound Techniques (TRUST): systematic review of reliability studies in obstetrics and gynecology
Authors: Coelho Neto M. A. , Roncato P. , Nastri C. O. , Martins W. P. 
Published: September 2014

ABSTRACTObjectivesTo examine the quality of methods used and the accuracy of the interpretation of agreement in existing studies that examine the reliability of ultrasound measurements and judgments in obstetrics and gynecology.MethodsA systematic search of MEDLINE was performed on 25 March 2014, looking for studies that examined the reliability of ultrasound measurements and judgments in obstetrics and gynecology with evaluation of concordance (CCC) or intraclass (ICC) correlation coefficients or kappa as a main objective.ResultsSeven hundred and thirty‐three records were examined on the basis of their title and abstract, of which 141 full‐text articles were examined completely for eligibility. We excluded 29 studies because they did not report CCC/ICC/kappa, leaving 112 studies that were included in our analysis. Two studies reported both ICC and kappa and were counted twice, therefore, the number used as the denominator in the analyses was 114. Only 16/114 (14.0%) studies were considered to be well designed (independent acquisition and blinded analysis) and to have interpreted the results properly. Most errors occurring in the studies are likely to overestimate the reliability of the method examined.ConclusionsThe vast majority of published studies examined had
important flaws in design, interpretation and/or reporting. Such limitations are important to identify as they might create false confidence in the existing measurements and judgments, jeopardizing clinical practice and future research. Specific guidelines aimed at improving the quality of reproducibility studies that examine ultrasound methods should be encouraged. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
Raptor abundance and northern bobwhite survival and habitat use
Authors: Turner Joshua W. , Hernández Fidel , Boal Clint W. , Ballard Bart M. , Bryant Fred C. , Wester David B. 
Published: September 2014

ABSTRACTPredation risk has a profound influence on prey behavior and habitat use. The Rio Grande Plains ecoregion of Texas, USA, provides a unique opportunity to investigate changes in prey behavior because the ecoregion experiences a high influx of raptors every year during autumn migration. We used an 8‐year data set (2000–2008) of radiocollared northern bobwhites (Colinus virginianus) and raptor abundance to test the hypothesis that bobwhites responded to increased raptor abundance via changes in woody‐cover use at the home‐range scale. Bobwhite survival was negatively correlated with raptor abundance, with red‐tailed hawks (Buteo jamaicensis), and northern harriers (Circus cyaneus) accounting for 51% of the variability in bobwhite survival (P < 0.010). However, we documented no change in the amount of woody cover used by bobwhites in their home range between the raptor migration (6.6% ± 0.5%; n = 73 bobwhites) and non‐migration periods (7.1% ± 0.4%; n = 105 bobwhites; P = 0.490). In addition, bobwhites that survived the raptor migration period used similar amounts of woody cover within their home range (6.3% ± 0.6%, n = 58 bobwhites) compared with those dying during the migration period (6.8% ± 0.4%, n = 100 bobwhites; P = 0.530). Our data suggest that bobwhites do not alter their use of woody cover at the home‐range scale in response to increasing raptor abundance, but this does not preclude increased use of woody cover at the point‐of‐use scale. © 2014 The Wildlife Society.
Identification of appropriate reference genes for human mesenchymal stem cell analysis by quantitative real-time PCR
Authors: Li Xiuying , Yang Qiwei , Bai Jinping , Xuan Yali , Wang Yimin 
Published: September 2014

AbstractNormalization to a reference gene is the method of choice for quantitative reverse transcription-PCR (RT-qPCR) analysis. The stability of reference genes is critical for accurate experimental results and conclusions. We have evaluated the expression stability of eight commonly used reference genes found in four different human mesenchymal stem cells (MSC). Using geNorm, NormFinder and BestKeeper algorithms, we show that beta-2-microglobulin and peptidyl-prolylisomerase A were the optimal reference genes for normalizing RT-qPCR data obtained from MSC, whereas the TATA box binding protein was not suitable due to its extensive variability in expression. Our findings emphasize the significance of validating reference genes for qPCR analyses. We offer a short list of reference genes to use for normalization and recommend some commercially-available software programs as a rapid approach to validate reference genes. We also demonstrate that the two reference genes, β-actin and glyceraldehyde-3-phosphate dehydrogenase, are frequently used are not always successful in many cases.
Segregation in dense sheared flows: gravity, temperature gradients, and stress partitioning
Authors: Hill K. M. , Tan Danielle S. 
Published: September 2014

AbstractIt is well-known that in a dense, gravity-driven flow, large particles typically rise to the top relative to smaller equal-density particles. In dense flows, this has historically been attributed to gravity alone. However, recently kinetic stress gradients have been shown to segregate large particles to regions with higher granular temperature, in contrast to sparse energetic granular mixtures where the large particles segregate to regions with lower granular temperature. We present a segregation theory for dense gravity-driven granular flows that explicitly accounts for the effects of both gravity and kinetic stress gradients involving a separate partitioning of contact and kinetic stresses among the mixture constituents. We use discrete-element-method (DEM) simulations of different-sized particles in a rotated drum to validate the model and determine diffusion, drag, and stress partition coefficients. The model and simulations together indicate, surprisingly, that gravity-driven kinetic sieving is not active in these flows. Rather, a gradient in kinetic stress is the key segregation driving mechanism, while gravity plays primarily an implicit role through the kinetic stress gradients. Finally, we demonstrate that this framework captures the experimentally observed segregation reversal of larger particles downward in particle mixtures where the larger particles are sufficiently denser than their smaller counterparts.
Pressure Hessian and viscous contributions to velocity gradient statistics based on Gaussian random fields
Authors: Wilczek Michael , Meneveau Charles 
Published: September 2014

AbstractUnderstanding the non-local pressure contributions and viscous effects on the small-scale statistics remains one of the central challenges in the study of homogeneous isotropic turbulence. Here we address this issue by studying the impact of the pressure Hessian as well as viscous diffusion on the statistics of the velocity gradient tensor in the framework of an exact statistical evolution equation. This evolution equation shares similarities with earlier phenomenological models for the Lagrangian velocity gradient tensor evolution, yet constitutes the starting point for a systematic study of the unclosed pressure Hessian and viscous diffusion terms. Based on the assumption of incompressible Gaussian velocity fields, closed expressions are obtained as the results of an evaluation of the characteristic functionals. The benefits and shortcomings of this Gaussian closure are discussed, and a generalization is proposed based on results from direct numerical simulations. This enhanced Gaussian closure yields, for example, insights on how the pressure Hessian prevents the finite-time singularity induced by the local self-amplification and how its interaction with viscous effects leads to the characteristic strain skewness phenomenon.
The effectiveness of an air curtain in the doorway of a ventilated building
Authors: Frank D. , Linden P. F. 
Published: September 2014

AbstractAir curtains are used to reduce the heat and mass exchange across open doorways. Their sealing ability is assessed in terms of the effectiveness $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}E$, the fraction of the exchange flow prevented by the air curtain compared to an unobstructed open door. Previous work has studied air-curtain effectiveness when the doorway is the only means of ventilating a space. In this paper, we examine the effects of additional displacement ventilation on the dynamics of the air curtain and the resulting changes in its effectiveness. The main controlling parameter is the deflection modulus $D_{m}$, which is the ratio between the momentum flux of the air curtain and the transverse forces due to the displacement ventilation. For a relatively warm interior, we find that, for small values of $D_{m}$, the air curtain is drawn inside the space by the ventilation flow. For large values of $D_{m}$, the flow through the doorway is controlled by the air curtain. A smooth transition occurs between these two regimes, and we estimate the $D_{m}$ value for the onset of this transition. Our model provides a quantitative prediction of $E(D_{m})$ in the ventilation-driven regime, and gives a qualitative description of the other two regimes. Laboratory experiments were conducted to test the proposed model. The experimental data were compared to theoretical predictions, and good agreement was found.
Fluid flow analysis of a shark-inspired microstructure
Authors: Martin Samuel , Bhushan Bharat 
Published: September 2014

AbstractThe scales of fast-swimming sharks contain riblet structures with microgrooves, aligned in the direction of fluid flow, that result in water moving efficiently over the surface. In previous studies, these riblet structures have shown a drag reduction of up to 10 % when compared with a smooth, flat surface. These studies have suggested two prevalent drag-reduction mechanisms which involve the effect of vortices and turbulence fluctuations. To further explore relevant mechanisms and study the effect of riblet geometry and flow properties on drag, vortices and turbulence fluctuations, various shark-skin-inspired riblet structures were created using computational models in which velocity, viscosity, spacing, height and thickness parameters were independently modified. A relevant mechanism of drag reduction is discussed to relate riblet parameters and flow properties to drag change and vortex size. Modelling information will lead to a better understanding of riblets and allow for optimum drag-reducing designs for applications in marine, medical and industrial fields.
Evolution of the velocity-gradient tensor in a spatially developing turbulent flow
Authors: Gomes-Fernandes R. , Ganapathisubramani B. , Vassilicos J. C. 
Published: September 2014

AbstractAn experimental study of turbulence generated by a low-blockage space-filling fractal square grid was performed using cinematographic stereoscopic particle image velocimetry in a water tunnel. All fluctuating velocity gradients were measured and their statistics were computed at three different stations along the streamwise direction downstream of the grid: in the production region, at the location of peak turbulence intensity and in the non-equilibrium decay region. The usual signatures of these statistics are only found in the decay region, where a well-defined$\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}2/3$power-law dependence of the second-order structure function on two-point distance is also present. However, this$2/3$exponent is well defined over a wide range of scales even at the peak location, where the statistics of the fluctuating velocity-gradient tensor are very unusual. There, as at the production region station, the$Q\text {--}R$teardrop shape is not yet fully developed, vortex stretching only slightly dominates over compression and they both fluctuate very widely, reaching very high low-probability values. In these two stations, there is also only marginal preference between sheet-like and tube-like velocity-gradient structures as seen by the sign of the second eigenvalue of the strain-rate tensor. Yet, there are subregions of the flow in the production region where the$2/3$exponent is present and where the$Q\text {--}R$teardrop shape is as undeveloped as for the entire data set at this station.
A run-time representation of scheme record types
Authors: KEEP ANDREW W. , DYBVIG R. KENT 
Published: September 2014

AbstractThe Revised6Report on the Algorithmic Language Scheme added a mechanism to the Scheme programming language for creating new record types procedurally. While many programming languages support user defined, structured data types, these are usually handled syntactically, so that the compiler can make choices at compile time about the memory layout of these data types. The procedural record types in Scheme, however, can be constructed at run time, making the efficient run-time representation of record types important to ensure good run-time performance. The run-time representation used in our implementation provides an extended model for record types allowing record types to represent foreign scalar data types, e.g., machine word integers, and allows the base record type to be extended to create non-R6RS record-type systems. This article describes our run-time representation for record types, how the garbage collector handles foreign scalar data types, and includes extended record type systems both for an object-oriented programming model and a representation of foreign structured data types.