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Abstract: Most of the planet's population currently lives in urban areas, and urban land expansion is one of the most dramatic forms of land conversion. Understanding how cities evolve temporally, spatially, and organizationally in a rapidly urbanizing world is critical for sustainable development. However, few studies have examined the coevolution of urban attributes in time and space simultaneously and the adequacy of power law scaling across cities and through time, particularly in countries that have experienced abrupt, widespread, political and economic changes. Here, we show the temporal coevolution of multiple physical, demographic, socioeconomic, and environmental attributes in individual cities, and the cross‐city scaling of urban attributes at six time points (i.e., 1978, 1990, 1995, 2000, 2005, and 2010) in 32 major Chinese cities. We found that power law scaling could adequately characterize both the cross‐city scaling of urban attributes across cities and the longitudinal scaling describing the temporal coevolution of urban attributes within individual cities. The cross‐city scaling properties demonstrated substantial changes over time signifying evolved social and economic forces. A key finding was that the cross‐city linear or superlinear scaling of urban area with population contradicts the theoretical sublinear power law scaling proposed between infrastructure and population. Furthermore, the cross‐city scaling between area and population transitioned from linear to superlinear over time, and the superlinear scaling in recent times suggests decreased infrastructure efficiency. Our results demonstrate a diseconomy of scale in urban areal expansion that indicates a significant waste of land resources in the urbanization process. Future planning efforts should focus on policies that increase urban land use efficiency before continuing expansion. [ABSTRACT FROM AUTHOR]

As one of the most important engineering structures, arch dams are huge constructions built with human hands and have strategical importance. Because of the fact that long construction duration, water supply, financial reasons, major loss of life and material since failure etc., the design of arch dams is very important problem and should be done by expert engineers to determine the structural behavior more accurately. Finite element analyses and non-destructive experimental measurements can be used to investigate the structural response, but there are some difficulties such as spending a long time while modelling, analysis and in-situ testing. Therefore, it is more useful to conduct the research on the laboratory conditions and to transform the obtained results into real constructions. Within the scope of this study, it is aimed to determine the structural behavior of arch dams considering experimentally validated prototype laboratory model using similitude and scaling laws. Type-1 arch dam, which is one of five arch dam types suggested at the "Arch Dams" Symposium in England in 1968 is selected as reference prototype model. The dam is built considering dam-reservoir-foundation interaction and ambient vibration tests are performed to validate the finite element results such as dynamic characteristics, displacements, principal stresses and strains. These results are considered as reference parameters and used to determine the real arch dam response with different scales factors such as 335, 400, 416.67 and 450. These values are selected by considering previously examined dam projects. Arch heights are calculated as 201 m, 240 m, 250 m and 270 m, respectively. The structural response is investigated between the model and prototype by using similarity requirements, field equations, scaling laws etc. To validate these results, finite element models are enlarged in the same scales and analyses are repeated to obtain the dynamic characteristics, displacements, principal stresses and strains. At the end of the study, it is seen that there is a good agreement between all results obtained by similarity requirements with scaling laws and enlarged finite element models. [ABSTRACT FROM AUTHOR]

Experiments dealing with impact of large structures, like ships and buses, are cost prohibitive. One possibility is to test scaled models, which unfortunately do not obey the scaling laws due to material strain rate sensitivity. A set of scaling numbers is here presented that allow perfect similarity between model and strain rate sensitive prototypes. It is shown how nonscaled models can be used to predict the prototype behavior. As a complement, it is commented on recent developments of new scaling laws that allow model and prototype with different densities to be directly compared. [ABSTRACT FROM AUTHOR]

Electromechanical resonators are used as viscosity sensors where the effect of the fluid loading on the resonance parameters is evaluated. A complete numerical analysis is often unrealistic due to the large computational effort. We introduce a reduced-order fluid impedance model valid for a large class of geometries. The fluid structure interaction is characterized by three parameters, an effective volume, an effective interaction surface, and an effective length. For idealized geometries these parameters can be derived analytically. We derive scaling laws for rectangular cross sections which are relevant for quartz tuning fork resonators. [ABSTRACT FROM AUTHOR]

The algorithm proposed by Shigeno et al. (2000) is a scaling method to solve the minimum cost-ow problem. In each phase, they applied the most positive cut canceling idea. In this paper, we present a new approach to solve the problem, which uses the scaling method of Shigeno et al. (2000); but, in each phase, we apply the out-of-kilter idea instead of the most positive cut canceling idea. Our algorithm is inspired by Ghiyasvand (2012). The algorithm gives a geometrical explanation for the optimality concept. For a network with n nodes and m arcs, the algorithm performs O(log(nU)) phases and runs in time O(m(m + n log n) log(nU)) (where U is the largest absolute arc bound), which is O(m(m+n log n) log n) under the similarity assumption. This time is the current best strongly polynomial time to solve the minimum cost-flow problem presented by Orlin (1993) and Vygen (2002). [ABSTRACT FROM AUTHOR]

This investigation concerns the determination of the scaling laws based on the similitude theory for beams and plates cases when loaded statically and with low velocity impact, respectively. Understanding the relationship between model and prototype behaviour is essential in scaled down models designs. The similarity conditions are established directly from the system field equations. Theoretical predictions of the model were projected with each scaling law and compared with the prototype theoretical predictions. Both finite element analysis and experimental tests were compiled for studied cases. The results obtained, using the similitude theory, were in good agreement with the experimental and numerical results. The scaling laws, which produced good predictions, were identified. The prediction depended on the scaling variables range used to stay within acceptable accuracy. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Source-scaling relations are an integral component of probabilistic seismic-hazard analysis (PSHA). These models that enable finite-rupture dimensions to be computed for a given earthquake scenario provide the link between magnitude-frequency distributions and ground-motion models. However, the development of scaling relations has not traditionally been undertaken in a manner that is consistent with their application within the hazard analysis. The causative problem is that rupture widths saturate as a result of the limited seismogenic thickness in any given region. This saturation has not previously been dealt with in a consistent manner, either in the development of scaling relations or in their typical application. This article approaches the development of source-scaling relations for shallow crustal earthquakes in active regions in an entirely new way that results in models that are physically consistent and consistent with the assumptions of PSHA. The innovative treatment of the width saturation issue results in new models that feature nonlinear scaling of the expected values, as well as strongly heteroskedastic variances. The first set of correlation coefficients is also provided for the rupture dimensions so that their joint variability can be appropriately accounted for within PSHA. The findings of the article have significant implications for hazard analysis, as the conditional distribution of finite-rupture distances for a given magnitude differs quite markedly from those suggested by existing approaches. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses uncertainty inherent to water demand and proposes an approach to generate demand scenarios and calculate their probability of occurrence. Nodal water demands are modelled as correlated stochastic variables. The parameters which characterize demand vary with spatial and temporal aggregation levels. Scaling laws allow the definition of these parameters for different users and sampling rates. Different scenarios are generated by considering different combinations of demands at each node of the network. A multivariate normal distribution is used to obtain the probability of each demand scenario. Correlation between demands is found to significantly affect the scenarios probabilities. [Copyright &y& Elsevier]

The lateral and longitudinal spacing between individual turbines in a wind turbine array must be large enough to minimize the wake effects caused by an upstream turbine on those that lie downstream from it. Here, the flow downstream of a single wind turbine is examined by modeling its far-field development as a turbulent axisymmetric wake which is well described in the turbulence literature. In particular, the velocity defect profile in the wake is approximated by a Gaussian function in the radial coordinate. Scaling laws are used to derive closed-form solutions for the wake diameter, wake velocity defect, and wake power recovery as functions of downstream distance from the rotor. Our results show that at a downstream distance of 10 rotor diameters, the wake centerline velocity will recover to 77% of the free-stream value. It is also seen that the power within the wake recovers quickly for small downstream distances, but beyond about 10 rotor diameters, the rate of power recovery slows down. Implications for the optimal spacing of wind turbines are discussed based on these findings. [ABSTRACT FROM AUTHOR]

Abstract: Understanding pattern of species diversity is a central goal of the science of ecology, and scaling laws are useful for revealing biodiversity patterns across scales. A transect along an altitudinal gradient in Dinghushan Reserve was used to test for the fractal effect in subtropical forest, and the multifractal method was used to validate the common scaling law of diversity. The results showed that: (1) richness-abundance pattern has self-similar relations (fractal effect) in the community despite a significant altitudinal gradient and habitat heterogeneity; (2) the power-law scaling relationship holds for all stratal levels of the forest (trees, shrubs and herbs), and hence scaling laws were significant; and, (3) the Shannon index was the optimal descriptor of tree species diversity information, but not shrub or herb diversity information in this subtropical forest. We also found that diversity indices that corresponding to q >1 are descriptive of communities dominated by common species. In contrast, diversity indices that corresponding to q <1 are suitable for communities with large numbers of rare species and high species evenness. The range of values of q for which scaling laws existed increased with the increasing latitude. [Copyright &y& Elsevier]

Glaciar San Rafael in the Northern Patagonia Icefield, with a length of 46 km and an ice area of 722 km², is the lowest latitude tidewater outlet glacier in the world and one of the fastest and most productive glaciers in southern South America in terms of iceberg flux. Spatio-tempora] velocity fields in the region of the glacier front were determined from monoscopic terrestrial image sequences recorded by an intervallometer mode high-resolution digital camera over several days. In these image sequences, a large number of glacier surface points were tracked by subpixe] accuracy feature tracking techniques. Scaling and georeferencing of the trajectories obtained from image space tracking was performed using a multi-station GPS-supported photogrummetric network. The technique allows for tracking hundreds of glacier surface points at a measurement accuracy in the order of one decimeter, for typical glacier movement rates, and an almost arbitrarily high temporal resolution. The results show velocities of up to 16 meters per day. [ABSTRACT FROM AUTHOR]

Abstract: An alternate inner wall variable, for flow over a transitional rough pipe surface, is defined as the ratio of normal coordinate measured above the mean roughness level to the wall roughness scale. The Reynolds equations for mean turbulent flow in a transitional rough pipe, in two layers (inner and outer) are considered. The predictions of the mean velocity and friction factor in fully developed turbulent flow in a rough pipe flow, presented here, covers all types of roughness. The data for a particular case of the machine honed Princeton superpipe roughness, analogous to inflectional type roughness of Nikuradse, is presented, as two expressions using our roughness scale. The velocity profile and friction factor, on a transitional rough wall, are shown to be governed by the new log laws, which are explicitly independent of the transitional wall roughness. Further, the inflectional roughness has also been connected with geometric roughness parameters; like, arithmetic mean roughness, mean peak to valley heights roughness, root mean square (rms), roughness based on texture measure; and the friction factor implicit and approximate explicit formulas have also been proposed. In entire transition region between fully smooth and fully rough wall, monotonic roughness of Colebrook (Moody Chart) over estimaton the friction factor when compared with present inlectional roughness. [Copyright &y& Elsevier]

We estimate the source parameters (seismic moment, source radius, stress drop, and source displacement) and scaling laws for local earthquakes that occurred in the Shillong-Mikir plateau, Assam Valley, and Arunachal Himalaya in northeast India during 2001-2008. The source parameters were determined using the spectral analysis of P waves from the vertical component seismograms, after cor-rection for attenuation. Seismic moments are observed within the range from 9.51 x 1012 to 2.74 x 1015 N-m; stress drop ranges from 4 x 105 to 9 x 107 Pa for the Brune model and 7 x 105 to 1 x 108 Pa for the Madariaga model. Seismic events in this study are prominent with an average stress drop of 0.1-10 MPa. The effect of site geology may be a contributing factor for such a variation in stress drop. Source dimensions are, however, found to be smaller within the major part of the plateau. It is suggested that local earthquakes in the region are associated with a brittle shear-failure mechanism on fault segments and/or the presence of weakened zones, and earth-quakes are triggered by low deviatoric stress. Empirical relations between Mw-A/L and M0-Ml are developed leading to the future prediction of calibration coefficients for the local earthquakes in the Shillong-Mikir plateau and its adjoining region [ABSTRACT FROM AUTHOR]

Scale and scaling are important conceptual and methodological issues in geography and ecology. Grain, one indicator of scale, is widely used to determine the scaling behaviors of landscape spatial patterns represented by landscape metrics. This study compared two strategies, including a high-resolution-data-based resampling (RS) approach and a multisource and multiresolution data (MSMRD) approach, to quantify the grain effects of nine commonly used landscape metrics determined by FRAGSTATS software. Three adjacent, small watersheds in the central Loess Plateau of China were selected as study sites. Using the RS and MSMRD approaches, five and seven landscape metrics, respectively, were detected to have significant and mostly linear grain effects. The MSMRD approach was more effective in detecting grain effects, and landscape areas were found to be important in the grain effects of landscape metrics. Changing grain means changing the spatial analysis or landscape observation scales and, thus, the quality of landscape pattern information acquired, without impacting the ground-surface landscape pattern. In this sense, the analysis of scale effects through the manipulation of grains can be practically implemented in spatial data processing and selection for landscape modeling tasks. This paper also highlights gaps in present scaling research on landscape metrics by their numerical responses to grain sizes, with the conceptual and mathematical formulations largely neglected. The latter, however, is more important in research concerning landscape metrics, such as scaling, correlation, and even the interaction between landscape patterns and ecological processes. [ABSTRACT FROM AUTHOR]

The multiresolution analysis (MRA) on certain non-abelian locally compact groups G is considered. Characterizations for a refinable function to generate an MRA in L²(G) are given. Here, no regularity properties or decay conditions are placed on the scaling functions. MRAs for L²(G) generated by a self-similar tile as a scaling function are shown and Haar-like wavelet bases are constructed. Concrete examples related to Heisenberg group are provided to illustrate the theorems. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To identify important challenges which are necessary to overcome for conducting the RAMS (Reliability, availability, maintainability and safety) analysis in an efficient and cost effective way. Methodology: RAMS analysis has become an active area of research to measure the efficiency of any operational system for evaluating its performance as per its designed features. The accuracy of measurements and analysis heavily depend upon how the RAMS related issues and challenges are addressed before planning the operational strategies to enhance the system availability for power output. It means that different RAMS related aspects are to be identified in congruent with the start of the design for a new product. So for providing sound basis for RAMS related analysis, an investigation has been carried out to identify important challenges which need to be addressed for having a robust and cost effective product satisfying the design parameters and operational strategies in a holistic way. For this purpose 10 MW reference wind turbine has been selected as a case study which is in the conceptual design phase now a day. For highlighting important challenges and issues, the framework has been developed to see how the design choice influences the operations. Moreover the particular design choice could also get feedback from operations to make new generations of the product in a better and innovative way. Results (expected): The feedback being acquired from the operational phase will provide basis to conduct the finite element and fatigue load analyses to find the areas prone to higher stress concentration. Based on such information, necessary modifications and improvements could be suggested for latest versions of that product. Maximum power capacity of existing wind turbines is 5 MW and to double the output of such machines is not a simple scaling problem. So the identification of important RAMS challenges and issues are directly helpful to solve such scaling problems to make these new machines more reliable and consequently more attractive for investors. The integration of design process and RAMS aspects in the proposed way will end in harmonizing and solving the scaling issues for bigger machines even beyond 10 MW reference wind turbine and making them viable from operational and investment point of view. [Copyright &y& Elsevier]

Integrating raster-based categorical maps from multiple sources necessitates the transformation of geometric charac- teristics to compare maps, as in land change analyses. By projecting maps to a new geographic reference framework and scaling pixel values to a new size, distortions of map information are introduced that can affect the proportion and arrangement of thematic classes across the landscape. Using a sample land cover dataset depicting a heteroge- neous landscape, this paper examines these impacts using three common raster-based transformation methods and intraduces a new vector-based method that minimizes error propagation. While relative class area was best preserved by a nearest-neighbor resampling method, distortions to the contiguity of thematic classes and the overall fragmentation of the landscape were minimized when using the vector- based projection and resampling method. Results demon- strate that more than a third af pixel values of a categorical map may be affected by common projection and scaling methods and reinforce the need for careful attention to impacts of error propagation in categorical data transformations. [ABSTRACT FROM AUTHOR]

Abstract: Multi fidelity optimization can be utilized for efficient design of airfoil shapes. In this paper, we investigate the scaling properties of algorithms exploiting this methodology. In particular, we study the relationship between the computational cost and the size of the design space. We focus on a specific optimization technique where, in order to reduce the design cost, the accurate high fidelity airfoil model is replaced by a cheap surrogate constructed from a low fidelity model and the shape preserving response prediction technique. In this study, we consider the design of transonic airfoils and use the compressible Euler equations in the high fidelity computational fluid dynamic (CFD) model. The low fidelity CFD model is same as the high fidelity one, but with coarser mesh resolution and reduced level of solver converge. The number of design variables varies from 3 to 11 by using NACA 4 digit airfoil shapes as well as airfoils constructed by Bézier curves. The results of the three optimization studies show that total cost increases from about 12 equivalent high fidelity model evaluations to 34. The number of high fidelity evaluations increases from 4 to 9, whereas the number of low fidelity evaluations increases more rapidly, from 600 to 2000. This indicates that, while the overall optimization cost scales more or less linearly with the dimensionality of the design space, further cost reduction can be obtained through more efficient optimization of the surrogate model. [Copyright &y& Elsevier]

Abstract: The micro scale simulation of CO2 sequestration involves complex, porous-like geometries. For the generation of such geometries, we present two approaches: In 2D, we construct a fractured domain by channel networks. In 3D, we approximate sand grain-like scenarios by dense sphere packings. The flow through these structures is simulated with the incompressible Navier-Stokes solver of the PDE framework Peano. Using an upscaling scheme, the results of the micro scale are used as input data for a Darcy solver on the coarse scales. The coupling concept and the scenario generators are presented together with first simulation results showing the validity of the approach. [Copyright &y& Elsevier]

Abstract: In order to get a good cleaning effect, we can change the location of ultrasonic cleaning device according to the ultrasonic propagation characteristics of ultrasonic. Judge by Doppler shift principle, this article build an equation which depict that ultrasonic disseminate in the mobile liquid. According to the relationship between viscous force and velocity gradient, this article build an equation which depicts that ultrasonic disseminate in the viscous liquid. The equation was facilitated and solved base on the characteristic of axial symmetry model. The results indicated that the velocity of mobile liquid can enhance the sound wave attenuation.The faster liquid flow rate, the higher the degree of attenuation. Liquid viscosity plays an important role in sound wave attenuation. The high frequency of ultrasonic, the more attenuation will produce. [Copyright &y& Elsevier]

Abstract: In this paper, the notion of matrix-valued multiresolution analysis is introduced. A procedure for designing biorthogonal matrix-valued quarternary wave wrap functions in is presented and their characters are researched by virtue of time-frequency analysis method, matrix theory and operator theory. Three biorthogonality formulas concerning the wave wrap functions are obtained. Finally, new Riesz bases of four dimensional matrix-valued function space are derived by designing a series of subspaces of biorthogonal matrix-valued wave wrap functions. [Copyright &y& Elsevier]

To better understand the physical mechanisms of slow slip events (SSEs) detected worldwide, we explore the scaling relationships of various source parameters and compare them with similar scaling laws for earthquakes. These scaling relationships highlight differences and similarities between slow slip events and earthquakes and hold implications for the degree of heterogeneity and fault-healing characteristics. The static stress drop remains constant for different-sized events as is observed for earthquakes. However, the static stress drop of slow slip events is within a range of 0.0 1-1.0 MPa, 1-2 orders of magnitude lower than that found for earthquakes, which could be related to the low stress state on the fault. The average rupture velocity, ranging from kilometers per second to kilometers per day, decreases linearly with increasing seismic moment in log-log space, unlike earthquakes that are nearly constant. This inverse relationship of rupture velocity with seismic moment could be related to the heterogeneity of fault properties. Slow slip events typically have ratios of event duration over dislocation rise time less than 3, while earthquakes have ratios greater than 3. This indicates that slow slip events are less pulselike than earthquakes in their mode of propagation and suggests that the healing behind the rupture front is delayed. The recurrence statistics of slow slip events on the northern Cascadia subduction zone are weakly time predictable and moderately antislip predictable (that is, the event size and preevent recurrence interval are anticorrelated), which may indicate that healing between events strengthens the fault with time. [ABSTRACT FROM AUTHOR]

The scaling effect, or influence of bored pile (drilled shaft) radius on unit shear capacity at a given displacement, is examined via a review of the literature as well as data collected in the field. It is apparent that the scaling effect of pile-soil load transfer is a measurable phenomenon on both the small scale and large scale. Since results from smaller-radius bored pile load tests are often used for the design of larger radius production piles, it may be advisable to scale down the unit shear capacity obtained from test results by the ratio of the test to production pile radii to conservatively account for the scaling effect. [ABSTRACT FROM AUTHOR]

This paper introduces a novel robust watermarking scheme for digital images, which is robust against common signal processing and geometric distortion attacks. In order to be resistant to geometric distortion attacks, the matched feature points determined by the scale-invariance feature transform (SIFT) are used for image restoration to reduce the synchronization errors caused by geometric distortion attacks. An adaptive embedding scheme is applied in discrete Fourier transform (DFT) domain of each subimage. The watermark detection decision is based on the number of matched bits between the retrieved and original watermark in the embedding image blocks. Experimental results show that the proposed watermarking is robust to common signal processing attacks and geometric distortion attacks, including rotation, scaling, cropping, shearing and some combined attacks. [ABSTRACT FROM AUTHOR]

Abstract: We summarize several decades of work in finding values for the percolation threshold pc for site percolation on the square lattice, the universal correction-to-scaling exponent, and the susceptibility amplitude ratio C+/C–, in two dimensions. Recent studies have yielded the precise values pc = 0:59274602(4), = 72=91 _ 0:791, and C+/C–= 161:5(2:0), resolving long-standing controversies about the last two quantities and verifying the widely used value pc = 0:592746 for the first. [Copyright &y& Elsevier]

Abstract: Due to the complex characteristics of bottle-brush polymers, it became a challenge to develop an e_cient algorithm for studying such macromolecules under various solvent conditions or some constraints in the space by using computer simulations. In the limit of a bottle-brush polymer with a rather sti_ backbone (straight rigid backbone), we generalize the variant of the biased chain growth algorithm, the pruned-enriched Rosenbluth method, for simulating polymers with complex architecture, from star polymers to bottle-brush polymers, on the simple cubic lattice. With the high statistics of our Monte Carlo results, we check the theoretical predictions of side chain behavior and radial monomer density profile. For the comparison of the experimental data for bottle-brush polymers with a flexible backbone and flexible side chains, based on the bond fluctuation model we propose another fast Monte Carlo algorithm combining the local moves, the pivot move, and an adjustable simulation lattice box. By monitoring the autocorrelation functions of gyration radii for the side chains and for the backbone, we see that for fixed side chain length there is no change in the behavior of these two functions as the backbone length increases. Our extensive results cover the range which is accessible for the comparison to experimental data and for the checking of the theoretically predicted scaling laws. [Copyright &y& Elsevier]

Abstract: The out-of-equilibrium properties of ferromagnets quenched below the critical point are discussed in the dynamical scaling limit. The autoresponse and the autocorrelation are studied for both perfect and disordered ferromagnets. The scaling functions of the autoresponse are found to be in agreement with the predictions coming from the theory of local scale-invariance. Large finite time corrections to the scaling behavior of the autocorrelation are revealed for the disordered magnets. [Copyright &y& Elsevier]

Abstract: Calculating the dipolar fields in LLG simulations account for the majority of the runtime as these computations scale with system size faster than the other interactions. Efficient parallelization of the dipolar field is essential for a parallel LLG solution. This article presents a method to dynamically generate a parallel strategy and examines the benefits in speedup over standard parallelization. [Copyright &y& Elsevier]

Abstract: The finite size scaling analysis of Monte Carlo data is discussed for two models for which hyperscaling is violated: (i) the random field Ising model (using a model for a colloid-polymer mixture in a random matrix as a representative) (ii) The Ising bi-pyramid in computing surface fields. [Copyright &y& Elsevier]

Abstract: We spectroscopically investigate the scaling properties of a metamaterial consisting of a square array of gold cylindrical dots. The electromagnetic response of the gold-dot array is found to scale in relation to the ratio of the incident wavelength over the array spacing, in agreement with general predictions of metamaterial theory. The appropriateness of an effective medium description of the array is analyzed in terms of the resonant polarizability of the array components, and the onset of van der Hulst backscattering at higher frequencies. [ABSTRACT FROM AUTHOR]

Copyright of Mathématiques & Sciences Humaines is the property of Editions du CNRS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Continuous long-term measurements of carbon fluxes have been obtained by improved technology at the ecosystem scale and under natural conditions. Nevertheless, these are still point measurements with limited geographic coverage Quantitative extrapolations and scaling-up of tower station measurements are now urgently needed for carbon cycle research. This paper attempts to solve this problem by combining the technologies of CO2 flux measurements, mathematic modeling, Geographic Information System (GIS) and Remote Sensing (RS). It is well known that the light-response function allows partitioning net ecosystem exchange (NEE) into gross primary production (GPP) and total ecosystem respiration (Re). The GPP and Re can be estimated from continuous CO2 flux measurements using non-linear identification of the non-rectangular hyperbolic model of ecosystem-scale, light response curves. Patterns of the relationships of GPP and Re with the Normalized Difference Vegetation Index (NDVI), and other factors, indicate possibilities to establish multivariate functions, allowing scaling-up of local fluxes to larger areas with GIS technology, temporal NDVI inversed from RS images, and other tools. Our study is based on continuous CO2 flux data, which were measured at the Haibei Alpine Meadow Ecosystem Research Station (Haibei Research Station) on the Qinghai-Tibet Plateau, the Chinese Academy of Science. Using the above methods, we achieved good flux-NDVI relationships at the site and applied these relationships in the scaling-up of site-specific CO2 flux measurements to regional levels. Consequently the annual spatial and temporal variation of CO2 flux was obtained for this plateau and eco-region. Characterizing spatial and temporal dynamics of CO2 flux will facilitate investigations of the carbon source or sink status of grassland ecosystems on the plateau. [ABSTRACT FROM AUTHOR]

The Gibbs phenomenon refers to the lack of uniform convergence which occurs in many orthogonal basis approximations to piecewise smooth functions. This lack of uniform convergence manifests itself in spurious oscillations near the points of discontinuity and a low order of convergence away from the discontinuities. In previous work [11,12] we described-a numerical procedure for overcoming the Gibbs phenomenon called the Inverse Wavelet Reconstruction method (IWR). The method takes the Fourier coefficients of an oscillatory partial sum and uses them to construct the wavelet coefficients of a non-oscillatory wavelet series. However, we only described the method standard wavelet series and not for the continuous wavelet transform. We also only described the method for so-called crude wavelets: wavelets which do not admit a scaling function, and therefore lack a multiresolution analysis. Here we describe a version of IWR based on a quadrature discretization of the continuous inverse wavelet transform. We also describe the multiresolution potential of the Inverse wavelet reconstruction method, which is the ability to decompose a function into a coarse trend plus finer details. [ABSTRACT FROM AUTHOR]

Most large earthquakes occur on several faults, and accordingly it is important to the prediction of earthquake size to know whether several adjacent faults rupture simultaneously and how slips are distributed on the simultaneously ruptured faults. In this article, I investigate slip-length scaling law, simulating spontaneous rupture processes on multisegmented strike-slip faults in a 3D half-space. Because of fault interaction, the amount of slip caused by simultaneous ruptures on two or more segments is larger than that of a rupture on a single segment. The fault interaction decreases with the distance between segments, thus the amount of slip attains a constant value when more than two segments rupture. The decrease of fault interaction also causes the small rate of slip increase for simultaneous ruptures on long segments. The numerical results physically support the empirical scaling law, which is characterized by a strong increase of slip with length and a tendency for slip to saturate for very long faults. [ABSTRACT FROM AUTHOR]

Abstract: The scaling behavior of linear polymers in disordered media, modelled by self-avoiding walks (SAWs) on the backbone of percolation clusters in two, three and four dimensions is studied by numerical simulations. We apply the pruned-enriched Rosenbluth chain-growth method (PERM). Our numerical results yield estimates of critical exponents, governing the scaling laws of disorder averages of the configurational properties of SAWs, and clearly indicate a multifractal spectrum which emerges when two fractals meet each other. [Copyright &y& Elsevier]

Abstract: This paper presents an algorithm that extracts robust feature descriptors from 2.5D range images, in order to provide accurate point-based correspondences between compared range surfaces. The algorithm is inspired by the two-dimensional (2D) Scale Invariant Feature Transform (SIFT) in which descriptors comprising the local distribution function of the image gradient orientations, are extracted at each sampling keypoint location over a local measurement aperture. We adapt this concept into the 2.5D domain by concatenating the histogram of the range surface topology types, derived using the bounded [−1,1] shape index, and the histogram of the range gradient orientations to form a feature descriptor. These histograms are sampled within a measurement window centred over each mathematically derived keypoint location. Furthermore, the local slant and tilt at each keypoint location are estimated by extracting range surface normals, allowing the three-dimensional (3D) pose of each keypoint to be recovered and used to adapt the descriptor sampling window to provide a more reliable match under out-of-plane viewpoint rotation. [Copyright &y& Elsevier]

ABSTRACT: In this paper the Auerbach''s scaling law of Hertzian fracture induced by a spherical indenter pressing on a brittle solid is studied. In the analysis, the singular integral equation method is used to analyze the fracture behavior of the Hertzian contact problem. The results show that the Auerbach''s constant sensitively depends on the Poisson''s ratio, and the effective Auerbach''s domain is also determined for a given value of the Poisson''s ratio. [Copyright &y& Elsevier]

As a universal conclusion of turbulent scale, scaling laws are important to the research on statistic turbulence. We measured two-dimensional instantaneous velocity field in turbulent boundary layers of flat plate with the momentum thickness Reynolds number Reθ=2 167. Scaling laws have different forms in different wall distance and scale. We proposed an expected scaling law and compared it with the She-Leveque (SL) scaling law based on the wavelet analysis and traditional statistical methods. Results show that the closer to the wall, the more the expected scaling law approached to the SL scaling law. [ABSTRACT FROM AUTHOR]

For reliable navigation, a mobile robot needs to be able to recognize where it is in the world. The aim of this paper is to present a robust vision-based approach to mobile robot localization, which employ visual features in environment in the system. In our approach, the robot does not have to measure its own position precisely and accurately, and rely only to the visual features which could be extracted from the environment. The features extraction method works simply and leads to a robust localization system. The proposed localization method has been implemented and tested in both indoor and outdoor environments. We present several experiments demonstrating the reliability and robustness of our approach. The achieved results are presented and discussed. [ABSTRACT FROM AUTHOR]

Abstract: This study integrates new and existing numerical modeling and experimental observations to provide a consistent explanation to observations pertaining flame length and soot volume fractions for laminar diffusion flames. Integration has been attempted by means of scaling analysis. Emphasis has been given to boundary layer flames. For the experiments, ethylene is injected through a flat porous burner into an oxidizer flowing parallel to the burner surface. The oxidizer is a mixture of oxygen and nitrogen, flowing at various velocities. All experiments were conducted in microgravity to minimize the role of buoyancy in distorting the aerodynamics of the flames. A previous numerical study emphasizing fuel transport was extended to include the oxidizer flow. Fictitious tracer particles were used to establish the conditions in which fuel and oxidizer interact. This allowed establishing regions of soot formation and oxidation as well as relevant characteristic length and time scales. Adequate scaling parameters then allow to establish explanations that are consistent for different burner configurations as well as “open-tip” and “closed-tip” flames. [Copyright &y& Elsevier]

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Abstract: A scale invariant feature transform (SIFT) based mean shift algorithm is presented for object tracking in real scenarios. SIFT features are used to correspond the region of interests across frames. Meanwhile, mean shift is applied to conduct similarity search via color histograms. The probability distributions from these two measurements are evaluated in an expectation–maximization scheme so as to achieve maximum likelihood estimation of similar regions. This mutual support mechanism can lead to consistent tracking performance if one of the two measurements becomes unstable. Experimental work demonstrates that the proposed mean shift/SIFT strategy improves the tracking performance of the classical mean shift and SIFT tracking algorithms in complicated real scenarios. [Copyright &y& Elsevier]

Time-scale spectra, obtained from seismic data wavelet transforms, are useful in analyzing local scaling properties of seismic signals. In particular, the wavelet transform modulus maxima (WTMM) spectra, obtained by following the local extrema of wavelet transforms along a constant phase line, describe characteristics of discontinuities such as interfaces. They also show a smooth behavior as a function of scale and thus allow us to derive local scaling laws. We use scaling behavior of WTMM spectra to enhance the bandwidth of seismic data. An analysis of well-log scaling behaviors and the seismic data shows that, whereas the WTMM spectrum of well logs at each interface exhibits a power-law behavior as a function of scale, the corresponding seismic signal spectrum shows a more complicated behavior, arising from seismic wavelet effects. Under the assumption that local well-log power-law behavior holds in general, a scaling law for seismic signals can be derived in terms of parameters that describe subsurface scaling effects and the seismic wavelet. A stable estimation of these parameters can be carried out simultaneously, as a function of time and over the seismic bandwidth, using the modified scaling law. No well-log information is needed to derive the seismic wavelet. Then wavelet transforms can be corrected for seismic wavelet effects and a high-resolution signal reconstructed. This reconstructed high-resolution signal can be used to map features that might not be obvious in the original seismic data, such as small faults, fractures, and fine-scale variations within channel margins. [ABSTRACT FROM AUTHOR]

Limit loads are determined in this paper by invoking the concept of equivalence of "static indeterminacy" that relates a multidimensional component configuration (with cracks) to a "reference two-bar structure." Simple scaling relationships are developed that enable rapid determination of limit loads. The method is applied to different crack configurations, and the limit loads are compared with corresponding results obtained from inelastic finite element analysis. [ABSTRACT FROM AUTHOR]

We propose a generation model for the main crack surface profile and parameterization of the chaotic regime of crack development. Chaos parameters allow predicting strength properties and can be used for the informal theory of fracture. [Copyright &y& Elsevier]

Abstract: There is growing recognition of the role of mechanistic scaling laws in shaping ecological pattern and process. While such theoretical relationships explain much of the variation across large scales, at any particular scale there is important residual variation that is left unexplained among species, among individuals within a species, and within individuals themselves. Key questions remain on what explains this variability and how we can apply this information in practice, in particular to produce estimates in high-diversity systems with many rare and under-sampled species. We apply hierarchical Bayes statistical techniques to data on crown geometry from diverse temperate forests in order to simultaneously model the differences within and among species. We find that tree height, canopy depth, and canopy radius are affected by both successional stage and wood mechanical strength, while tree height conforms to the predicted 2/3 power relationship. Furthermore, we show that hierarchical modeling allows us to constrain the allometries of rare species much more than traditional methods. Finally, crown radius was shown to vary substantially more within individuals than among individuals or species, suggesting that the capacity for local light foraging and crown plasticity exerts the dominant control on tree crowns. [Copyright &y& Elsevier]

The Bristol Bay, Alaska, fishery for red king crab Paralithodes camtschaticus is a male-only fishery. A safeguard against male overfishing is the requirement that at least 8.4 million successfully mated, newly fertilized females be present on the grounds each year; otherwise no harvest is permitted. Estimation of the number of mated females in the population is complicated by the timing of the Bering Sea trawl survey, which in most years moves through Bristol Bay before red king crab spawning is complete. From 1977 through 2000, an average of 22% (range, 0-87%) of the broodstock remained unmated at the time of the May-June survey. Eighty-nine percent of the observed annual variation in the proportion of unmated crabs was explained by water temperature and the date of the survey. Thus, the degree of mating success shown by each year's survey, although influenced by male availability, is predominantly an artifact of temperature and survey timing. Also, red king crabs tend to spawn in untrawlable nearshore waters, increasing the difficulty of obtaining unbiased estimates of abundance from sampling an open population. Because the proportion of mature females that emigrate each year to the nearshore spawning grounds is greater than that of males, the sex ratio within the sampled region of a survey conducted during spawning is biased toward males. This bias masks one of the more obvious signs of male overharvest--a male-depauperate sex ratio. Finally, a survey conducted during spawning cannot provide an accurate mapping of the spatial distribution of the postspawning broodstock returning from inshore spawning grounds to incubate their newly fertilized eggs during the next 10-12 months. A time-temperature model indicated that delaying the Bristol Bay red king crab survey until the end of June would ameliorate the problems caused by sampling an open population engaged in spawning. [ABSTRACT FROM AUTHOR]

The vibration time series of gear systems exhibit self-similarity. The time-series behavior is characterized by an exponent, known as the scaling exponent. An algorithm is proposed for the estimation of both global and local exponents, thus providing a means of examining the time-series fine structure. The proposed algorithm is applied to experimental data recorded from gear pairs with localized defects in the form of bending fatigue cracks. It is shown that an examination of the exponent empirical histogram allows detection of damage at an early stage and also provides an estimate of the defect magnitude. [ABSTRACT FROM AUTHOR]

Close-packed coupled multielectrode arrays simulating a planar electrode were used to monitor the anodic current evolution as a function of position during initiation and propagation of crevice corrosion of AISI 316 stainless steel (UNS 531600) and Ni- Cr-Mo alloy 625 (UNS N06625). Scaling laws X~rit vs G and x~ vs G derived from polarization data in simulated crevice solutions guided the implementation of resealed crevices with greater spatial resolution. Xcrit and are the distances from the mouth to the location where the potential reaches two different critical values, and G is the crevice gap. Scaling laws were also used along with anodic polarization data in simulated crevice solution to predict crevice corrosion behavior of alloy 22 (UNS N06022). Crevice corrosion of AISI 316 stainless steel in 0.6 mol/L NaCI at 50°C readily initiated close to the crevice mouth (i.e., x~1 0) at modest applied potentials (e.g., Eapp 0 V5~5) and spread both inward and outside the crevice with time. Crevice corrosion initiated farther inside the crevice (i.e., ~ is large) and required higher applied potentials (e.g., E~5~ = 50 mVscs) in the case of alloy 625. The local crevice current density increased dramatically over a short period of time to reach a limiting value in the case of AISI 316; while metastable dissolution behavior over a large area was observed for alloy 625. The ramification of the larger critical depth for Ni-Cr-Mo alloys toward crevice corrosion susceptibility in the case of crevice formers of finite length is discussed. Crevice corrosion shifts to the mouth of the crevice for the less corrosion-resistant materials in crevice solutions saturated in metal salts but remains confined at a distance x.,,, for alloy 625 under the conditions tested. [ABSTRACT FROM AUTHOR]