Journal articles: 'Local Mesh Adaptation'

7

Wada, Yoshitaka, Mamtimin Gheni, Masanao Matsumoto, and Masanori Kikuchi. "Effective Adaptation of Hexahedral Mesh using Local Refinement and Error Estimation." Key Engineering Materials 243-244 (July 2003): 27–32. http://dx.doi.org/10.4028/www.scientific.net/kem.243-244.27.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

St-Cyr, Amik, Christiane Jablonowski, John M. Dennis, Henry M. Tufo, and Stephen J. Thomas. "A Comparison of Two Shallow-Water Models with Nonconforming Adaptive Grids." Monthly Weather Review 136, no. 6 (2008): 1898–922. http://dx.doi.org/10.1175/2007mwr2108.1.

Full text

Abstract:

Abstract In an effort to study the applicability of adaptive mesh refinement (AMR) techniques to atmospheric models, an interpolation-based spectral element shallow-water model on a cubed-sphere grid is compared to a block-structured finite-volume method in latitude–longitude geometry. Both models utilize a nonconforming adaptation approach that doubles the resolution at fine–coarse mesh interfaces. The underlying AMR libraries are quad-tree based and ensure that neighboring regions can only differ by one refinement level. The models are compared via selected test cases from a standard test suite for the shallow-water equations, and via a barotropic instability test. These tests comprise the passive advection of a cosine bell and slotted cylinder, a steady-state geostrophic flow, a flow over an idealized mountain, a Rossby–Haurwitz wave, and the evolution of a growing barotropic wave. Both static and dynamics adaptations are evaluated, which reveal the strengths and weaknesses of the AMR techniques. Overall, the AMR simulations show that both models successfully place static and dynamic adaptations in local regions without requiring a fine grid in the global domain. The adaptive grids reliably track features of interests without visible distortions or noise at mesh interfaces. Simple threshold adaptation criteria for the geopotential height and the relative vorticity are assessed.

APA, Harvard, Vancouver, ISO, and other styles

9

Gheni, Mamtimin, X. F. Wang, and Masanori Kikuchi. "Study on Self-Consistent Mesh Generating Method of Hexahedron Element Based on the Local Waveform Method with Damping." Key Engineering Materials 306-308 (March 2006): 607–12. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.607.

Full text

Abstract:

Three-dimensional finite element method (FEM) is widely used as an effective numerical simulation technique to solve the complex engineering problem. In the FEM simulation technique at first it needs to discrete the problem. However, the almost all of the engineering problem have very complicated structure and shape, so that the mesh generation also have much difficulty. Furthermore, the correct generation of mesh is one of the most significant issues that directly affect to the accuracy of the FEM simulation. Though in extensive commercial software have an excellent automatic mesh generating system, however the problem of hexahedral automatic mesh generation and its adaptation are not enough to solve for practical applications, because for the mesh generation of complex shape is very difficult and still intensive labor work by hand. In this paper we present a new method to generate an appropriate mesh using existing regular hexahedral mesh and hexahedron mesh generation technique. This technique based on the wave transmits theory with damp named Waveform Mesh Generating (WMG) method. The results shown that the complex shaped FEM discrete hexahedral mesh model generated when shape of the side apply to regular mesh side as a waveform constraint.

APA, Harvard, Vancouver, ISO, and other styles

10

Tajs-Zielińska, Katarzyna, and Bogdan Bochenek. "CARMA—Cellular Automata with Refined Mesh Adaptation—The Easy Way of Generation of Structural Topologies." Applied Sciences 10, no. 11 (2020): 3691. http://dx.doi.org/10.3390/app10113691.

Full text

Abstract:

This paper is focused on the development of a Cellular Automata algorithm with the refined mesh adaptation technique and the implementation of this algorithm in topology optimization problems. Traditionally, a Cellular Automaton is created based on regular discretization of the design domain into a lattice of cells, the states of which are updated by applying simple local rules. It is expected that during the topology optimization process the local rules responsible for the evaluation of cell states can drive the solution to solid/void resulting structures. In the proposed approach, the finite elements are equivalent to cells of an automaton and the states of cells are represented by design variables. While optimizing engineering structural elements, the important issue is to obtain well-defined solutions: in particular, topologies with smooth boundaries. The quality of the structural topology boundaries depends on the resolution level of mesh discretization: the greater the number of elements in the mesh, the better the representation of the optimized structure. However, the use of fine meshes implies a high computational cost. We propose, therefore, an adaptive way to refine the mesh. This allowed us to reduce the number of design variables without losing the accuracy of results and without an excessive increase in the number of elements caused by use of a fine mesh for a whole structure. In particular, it is not necessary to cover void regions with a very fine mesh. The implementation of a fine grid is expected mainly in the so-called grey regions where it has to be decided whether a cell becomes solid or void. The benefit of the proposed approach, besides the possibility of obtaining high-resolution, sharply resolved fine optimal topologies with a relatively low computational cost, is also that the checkerboard effect, mesh dependency, and the so-called grey areas can be eliminated without using any additional filtering. Moreover, the algorithm presented is versatile, which allows its easy combination with any structural analysis solver built on the finite element method.

APA, Harvard, Vancouver, ISO, and other styles

11

Wada, Yoshitaka, Jun'ichi Shinbori, and Masanori Kikuchi. "Adaptive FEM Analysis Technique Using Multigrid Method for Unstructured Hexahedral Meshes." Key Engineering Materials 306-308 (March 2006): 565–70. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.565.

Full text

Abstract:

MG (multigrid) method is one of the most promising solvers for large scale problems. Hexahedral mesh generation and its adaptation are not enough to use for practical applications, because its mesh generation is very difficult and still labor intensive work by hand. We have developed hexahedral local refinement technique controlled by posterior error estimation. We have proposed a MG technique for unstructured hexahedral meshes with local mesh refinement. In this paper, the proposed technique is evaluated to check its performance and severe analyses of bending cantilevers. Performance of MG for unstructured hexahedral meshes is compared with that of the PCG (preconditioned conjugate gradient) through several benchmark examples of 3-D static elastic analysis. Proposed MG is faster than PCG for all problems as number of freedoms increases. Finally limitation of the proposed technique is presented.

APA, Harvard, Vancouver, ISO, and other styles

12

Byambaakhuu, Tseelmaa, Dean Wang, and Sicong Xiao. "A Coarse-Mesh Diffusion Synthetic Acceleration Method with Local hp Adaptation for Neutron Transport Calculations." Nuclear Science and Engineering 192, no. 2 (2018): 208–17. http://dx.doi.org/10.1080/00295639.2018.1499338.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Arif, Teuku Yuliar, Munandar Munandar, Ramzi Adriman, and Rizal Munadi. "CARA-OHT: Collision-Aware Rate Adaptation for Optimal High-Throughput in IEEE 802.11s Wireless Mesh Networks." International Journal of Interactive Mobile Technologies (iJIM) 14, no. 13 (2020): 172. http://dx.doi.org/10.3991/ijim.v14i13.13245.

Full text

Abstract:

The wireless mesh network (WMN) is a future network technology that develops single-hop wireless local area networks (WLANs) into multi-hop wireless mesh networks, based on the IEEE 802.11s standard. However, this development still presents many challenges, such as determining the best route between sources and destinations, especially taking into account the use of the medium access control (MAC) and physical (PHY) layers of IEEE 802.11n/ac. Some papers have proposed rate adaptation algorithms particularly for single-hop networks; however, these only focused on mechanisms to find data rates suitable for channel conditions. In IEEE 802.11s WMNs, the design of the rate adaptation algorithm is more challenging. Besides considering the problem of channel quality and optimal throughput, it is necessary to also consider the problem of collision and the best route. It is important to take collision into account because the collision probability in multi-hop mesh networks is higher than that in single-hop networks and can lead to a lower throughput. Rate adaptation algorithms for IEEE 802.11s WMNs have been proposed in other papers, but they also do not consider the use of the MAC and PHY layers of IEEE 802.11n/ac. In this paper, we propose the collision-aware rate adaptation for optimal high-throughput (CARA-OHT) algorithm for WMN IEEE 802.11s. An evaluation through the extensive use of a network NS-3 simulator shows that the proposed algorithm exhibits a higher throughput than previously developed algorithms.

APA, Harvard, Vancouver, ISO, and other styles

14

Bono, G., and A. M. Awruch. "A MESH ADAPTION METHOD BY NODE RE-ALLOCATION USING AN EDGE-BASED ERROR MEASURE." Revista de Engenharia Térmica 4, no. 2 (2005): 145. http://dx.doi.org/10.5380/reterm.v4i2.5416.

Full text

Abstract:

A mesh adaptation technique implemented in an algorithm to simulate compressible flows characterized by the presence of strong shocks, using the finite element method (FEM), is presented in this work. The initial mesh is continuously adapted during the solution process using a node movement technique, keeping as much as possible mesh smoothness and local orthogonality with an unconstrained optimization method. The error is estimated as a function of the Hessian tensor, containing second derivatives of the specific mass, and a Riemann metric projected on the element edges is obtained in order to determine node movements. Time and spatial discretization of the governing equations are carried out using an explicit Taylor-Galerkin scheme and an isoparametric hexahedrical element with eight nodes. An Arbitrary Lagrangean Eulerian (ALE) description is used to take into account mesh movement. Finally, some two-dimensional examples involving transonic and supersonic flows are presented to validate the algorithm.

APA, Harvard, Vancouver, ISO, and other styles

15

Sleiman, M., A. Tam, M. P. Robichaud, M. F. Peeters, and W. G. Habashi. "Multistage Simulation by an Adaptive Finite Element Approach Using Structured Grids." Journal of Fluids Engineering 121, no. 2 (1999): 450–59. http://dx.doi.org/10.1115/1.2822231.

Full text

Abstract:

This paper presents the application of a three-dimensional Navier-Stokes finite element code (NS3D) in the context of turbomachinery rotor-stator multistage interaction. A mixing-plane approach is used, in which boundary conditions at a common interface plane between adjacent blade rows are iteratively adjusted to yield a flow satisfying the continuity, momentum, and energy conservation equations, in an average sense. To further improve the solutions, a mesh adaptation technique then redistributes the mesh points of the structured grid within each component, according to an a posteriori edge-based error estimate based on the Hessian of the local flow solution. This matrix of second derivatives controls both the magnitude and direction of the required mesh movement at each node, is then implemented using an edge-based spring analogy. The methodology is demonstrated for two test cases with two types of data: a well-instrumented experimental large-scale rotating rig for a second stage compressor at UTRC and an actual engine. The latter, a two-stage compressor of a turboprop, has been only tested as a single-stage configuration, because of the quality of the experimental data available. All results compare well to the data and demonstrate the utility of the approach. In Particular, the mesh adaptation shows large improvements in agreement between the calculations and the experimental data.

APA, Harvard, Vancouver, ISO, and other styles

16

Nguyen, Vinh-Tan, Hoang Huy Nguyen, Matthew Antony Price, and Jaik Kwang Tan. "Shock capturing schemes with local mesh adaptation for high speed compressible flows on three dimensional unstructured grids." Computers & Fluids 70 (November 2012): 126–35. http://dx.doi.org/10.1016/j.compfluid.2012.09.011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Muller, Etienne, Dominique Pelletier, and André Garon. "Interactions between adaptive time-integrators and adaptive meshing in a monolithic FEM solver." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 7 (2019): 2297–323. http://dx.doi.org/10.1108/hff-09-2018-0495.

Full text

Abstract:

Purpose This paper aims to focus on characterization of interactions between hp-adaptive time-integrators based on backward differentiation formulas (BDF) and adaptive meshing based on Zhu and Zienkiewicz error estimation approach. If mesh adaptation only occurs at user-supplied times and results in a completely new mesh, it is necessary to stop the time-integration at these same times. In these conditions, one challenge is to find an efficient and reliable way to restart the time-integration. The authors investigate what impact grid-to-grid interpolation errors have on the relaunch of the computation. Design/methodology/approach Two restart strategies of the time-integrator were used: one based on resetting the time-step size h and time-integrator order p to default values (used in the initial startup phase), and another designed to restart with the time-step size h and order p used by the solver prior to remeshing. The authors also investigate the benefits of quadratically interpolate the solution on the new mesh. Both restart strategies were used to solve laminar incompressible Navier–Stokes and the Unsteady Reynolds Averaged Naviers-Stokes (URANS) equations. Findings The adaptive features of our time-integrators are excellent tools to quantify errors arising from the data transfer between two grids. The second restart strategy proved to be advantageous only if a quadratic grid-to-grid interpolation is used. Results for turbulent flows also proved that some precautions must be taken to ensure grid convergence at any time of the simulation. Mesh adaptation, if poorly performed, can indeed lead to losing grid convergence in critical regions of the flow. Originality/value This study exhibits the benefits and difficulty of assessing both spatial error estimates and local error estimates to enhance the efficiency of unsteady computations.

APA, Harvard, Vancouver, ISO, and other styles

18

Castro, C. E., M. Käser, and E. F. Toro. "Space–time adaptive numerical methods for geophysical applications." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1907 (2009): 4613–31. http://dx.doi.org/10.1098/rsta.2009.0158.

Full text

Abstract:

In this paper we present high-order formulations of the finite volume and discontinuous Galerkin finite-element methods for wave propagation problems with a space–time adaptation technique using unstructured meshes in order to reduce computational cost without reducing accuracy. Both methods can be derived in a similar mathematical framework and are identical in their first-order version. In their extension to higher order accuracy in space and time, both methods use spatial polynomials of higher degree inside each element, a high-order solution of the generalized Riemann problem and a high-order time integration method based on the Taylor series expansion. The static adaptation strategy uses locally refined high-resolution meshes in areas with low wave speeds to improve the approximation quality. Furthermore, the time step length is chosen locally adaptive such that the solution is evolved explicitly in time by an optimal time step determined by a local stability criterion. After validating the numerical approach, both schemes are applied to geophysical wave propagation problems such as tsunami waves and seismic waves comparing the new approach with the classical global time-stepping technique. The problem of mesh partitioning for large-scale applications on multi-processor architectures is discussed and a new mesh partition approach is proposed and tested to further reduce computational cost.

APA, Harvard, Vancouver, ISO, and other styles

19

BANGERTH, WOLFGANG, and ROLF RANNACHER. "ADAPTIVE FINITE ELEMENT TECHNIQUES FOR THE ACOUSTIC WAVE EQUATION." Journal of Computational Acoustics 09, no. 02 (2001): 575–91. http://dx.doi.org/10.1142/s0218396x01000668.

Full text

Abstract:

We present an adaptive finite element method for solving the acoustic wave equation. Using a global duality argument and Galerkin orthogonality, we derive an identity for the error with respect to an arbitrary functional output of the solution. The error identity is evaluated by solving the dual problem numerically. The resulting local cell-wise error indicators are used in the grid adaptation process. In this way, the space-time mesh can be tailored for the efficient computation of the quantity of interest. We give an overview of the implementation of the proposed method and illustrate its performance by several numerical examples.

APA, Harvard, Vancouver, ISO, and other styles

20

Walloth, Mirjam. "Residual-type a posteriori error estimator for a quasi-static Signorini contact problem." IMA Journal of Numerical Analysis 40, no. 3 (2019): 1937–71. http://dx.doi.org/10.1093/imanum/drz023.

Full text

Abstract:

Abstract We present a new residual-type a posteriori estimator for a quasi-static Signorini problem. The theoretical results are derived for two- and three-dimensional domains and the case of nondiscrete gap functions is addressed. We derive global upper and lower bounds with respect to an error notion, which measures the error in the displacements, the velocities and a suitable approximation of the contact forces. Further, local lower bounds for the spatial error at each discrete time point are given. The estimator splits in temporal and spatial contributions, which can be used for the adaptation of the time step as well as the mesh size. In the derivation of the estimator the local properties of the solution are exploited such that the spatial estimator has no contributions related to the nonlinearities in the interior of the actual time-dependent contact zone, but gives rise to an appropriate refinement of the free boundary zone.

APA, Harvard, Vancouver, ISO, and other styles

21

ElSheikh, A. H., S. E. Chidiac, and S. Smith. "Assessment of two a posteriori error estimators for elasticity problems." Canadian Journal of Civil Engineering 35, no. 11 (2008): 1239–50. http://dx.doi.org/10.1139/l08-063.

Full text

Abstract:

The main focus of this paper is on the evaluation of local a posteriori error estimation techniques for the finite element method (FEM). The standard error estimation techniques are presented for the coupled displacement fields appearing in elasticity problems. The two error estimators, the element residual method (ERM) and Zienkiewicz–Zhu (ZZ) patch recovery technique, are evaluated numerically and then used as drivers for a mesh adaptation process. The results demonstrate the advantages of employing a posteriori error estimators for obtaining finite element solutions with a pre-specified error tolerance. Of the two methods, the ERM is shown to produce adapted meshes that are similar to those adapted by the exact error. Furthermore, the ERM provides higher quality estimates of the error in the global energy norm when compared to the ZZ estimator.

APA, Harvard, Vancouver, ISO, and other styles

22

Biswas, Debojyoti, Peter N. Devreotes, and Pablo A. Iglesias. "Three-dimensional stochastic simulation of chemoattractant-mediated excitability in cells." PLOS Computational Biology 17, no. 7 (2021): e1008803. http://dx.doi.org/10.1371/journal.pcbi.1008803.

Full text

Abstract:

During the last decade, a consensus has emerged that the stochastic triggering of an excitable system drives pseudopod formation and subsequent migration of amoeboid cells. The presence of chemoattractant stimuli alters the threshold for triggering this activity and can bias the direction of migration. Though noise plays an important role in these behaviors, mathematical models have typically ignored its origin and merely introduced it as an external signal into a series of reaction-diffusion equations. Here we consider a more realistic description based on a reaction-diffusion master equation formalism to implement these networks. In this scheme, noise arises naturally from a stochastic description of the various reaction and diffusion terms. Working on a three-dimensional geometry in which separate compartments are divided into a tetrahedral mesh, we implement a modular description of the system, consisting of G-protein coupled receptor signaling (GPCR), a local excitation-global inhibition mechanism (LEGI), and signal transduction excitable network (STEN). Our models implement detailed biochemical descriptions whenever this information is available, such as in the GPCR and G-protein interactions. In contrast, where the biochemical entities are less certain, such as the LEGI mechanism, we consider various possible schemes and highlight the differences between them. Our simulations show that even when the LEGI mechanism displays perfect adaptation in terms of the mean level of proteins, the variance shows a dose-dependence. This differs between the various models considered, suggesting a possible means for determining experimentally among the various potential networks. Overall, our simulations recreate temporal and spatial patterns observed experimentally in both wild-type and perturbed cells, providing further evidence for the excitable system paradigm. Moreover, because of the overall importance and ubiquity of the modules we consider, including GPCR signaling and adaptation, our results will be of interest beyond the field of directed migration.

APA, Harvard, Vancouver, ISO, and other styles

23

Stavropulos-Laffaille, Xenia, Katia Chancibault, Jean-Marc Brun, et al. "Improvements to the hydrological processes of the Town Energy Balance model (TEB-Veg, SURFEX v7.3) for urban modelling and impact assessment." Geoscientific Model Development 11, no. 10 (2018): 4175–94. http://dx.doi.org/10.5194/gmd-11-4175-2018.

Full text

Abstract:

Abstract. Climate change and demographic pressures are affecting both the urban water balance and microclimate, thus amplifying urban flooding and the urban heat island phenomena. These issues need to be addressed when engaging in urban planning activities. Local authorities and stakeholders have therefore opted for more nature-based adaptation strategies, which are especially suitable in influencing hydrological and energy processes. Assessing the multiple benefits of such strategies on the urban microclimate requires high-performance numerical tools. This paper presents recent developments dedicated to the water budget in the Town Energy Balance for vegetated surfaces (TEB-Veg) model (surface externalisée; SURFEX v7.3), thus providing a more complete representation of the hydrological processes taking place in the urban subsoil. This new hydrological module is called TEB-Hydro. Its inherent features include the introduction of subsoil beneath built surfaces, the horizontal rebalancing of intra-mesh soil moisture, soil water drainage via the sewer network and the limitation of deep drainage. A sensitivity analysis is then performed in order to identify the hydrological parameters required for model calibration. This new TEB-Hydro model is evaluated on two small residential catchments in Nantes (France), over two distinct periods, by comparing simulated sewer discharge with observed findings. In both cases, the model tends to overestimate total sewer discharge and performs better under wet weather conditions, with a Kling–Gupta efficiency (KGE) statistical criterion greater than 0.80 vs. approximately 0.60 under drier conditions. These results are encouraging since the same set of model parameters is identified for both catchments, irrespective of meteorological and local physical conditions. This approach offers opportunities to apply the TEB-Hydro model at the city scale alongside projections of climate and demographic changes.

APA, Harvard, Vancouver, ISO, and other styles

24

Курбаналиев, Абдикерим Ырысбаевич, Бурулгул Рахманбердиевна Ойчуева, Анипа Ташбаевна Калмурзаева, Аманбек Жайнакович Жайнаков, and Топчубай Чокоевич Култаев. "Critical comparison of the different versions of the OpenFOAM on the simulation of spillway." Вычислительные технологии, no. 2 (June 22, 2021): 44–57. http://dx.doi.org/10.25743/ict.2021.26.2.004.

Full text

Abstract:

Приведены предварительные результаты численного моделирования двухфазного течения двух несжимаемых и несмешивающихся жидкостей через водослив трапециевидной формы. Целью работы была демонстрация возможностей решателя interFoam различных версий открытого пакета OpenFoam при моделировании рассматриваемого класса течений. Численные расчеты проведены с использованием входящего в состав OpenFoam руководства weirOverFlow. В пакете OpenFOAM6 коэффициент fvcDdtPhiCoeff для вычисления потоков массы на гранях ячеек изменен в целях улучшения устойчивости/точности и исключения осцилляций давления при высоких числах Куранта. Он вычисляется с использованием значений плотности и потока массы с предыдущего временн´ого шага. Результаты численных расчетов показывают, что такие изменения вызывают чрезмерно быстрый переход от нестационарного течения к стационарному. The results of numerical simulation for a two-phase flow of two incompressible and immiscible liquids through a trapezoidal spillway are presented. To simulate the free boundary, we used the method of fluid volume. The aim of the work was to demonstrate the capabilities of the various versions of interFoam solver of the OpenFOAM package for modelling the considered class of flows. Numerical calculations were performed using the OpenFOAM weirOverFlow tutorial. In order to improve the consistency, usability, flexibility and ease of modifying the interFoam solver, the existing interDyMFoam solver with the local dynamic mesh adaptation function was combined with the interFoam solver with a static computational mesh. In addition, in the OpenFOAM6 package, the fvcDdtPhiCoeff coefficient used for calculating the time derivative and taking into account the Rhie- Chow correction on the collocated grid for calculating mass fluxes on the cell faces was changed in order to improve stability/accuracy and eliminate pressure oscillations at high Courant numbers. The calculation of fvcDdtPhiCoeff coefficient in OpenFOAM5 requires the density value from the current time step along with the mass flow value from the previous time step, while in OpenFOAM6, both density and mass flow values are taken from the previous time step for calculation of the fvcDdtPhiCoeff coefficient. The results of numerical calculations of the OpenFOAM6 package show that such changes lead to an excessively fast transition of the transient flow to the stationary one in comparison with other versions of the OpenFOAM package.

APA, Harvard, Vancouver, ISO, and other styles

25

Ameduri, Salvatore, Ignazio Dimino, Antonio Concilio, Umberto Mercurio, and Lorenzo Pellone. "Specific Modeling Issues on an Adaptive Winglet Skeleton." Applied Sciences 11, no. 8 (2021): 3565. http://dx.doi.org/10.3390/app11083565.

Full text

Abstract:

Morphing aeronautical systems may be used for a number of aims, ranging from improving performance in specific flight conditions, to keeping the optimal efficiency over a certain parameters domain instead of confining it to a single point, extending the flight envelope, and so on. An almost trivial statement is that traditional skeleton architectures cannot be held as a structure modified from being rigid to deformable. That passage is not simple, as a structure that is able to be modified shall be designed and constructed to face those new requirements. What is not marginal, is that the new configurations can lead to some peculiar problems for both the morphing and the standard, supporting, elements. In their own nature, in fact, adaptive systems are designed to contain all the parts within the original geometry, without any “external adjoint”, such as nacelles or others. Stress and strain distribution may vary a lot with respect to usual structures and some particular modifications are required. Sometimes, it happens that the structural behavior does not match with the common experience and some specific adjustment shall be done to overcome the problem. What is reported in this paper is a study concerning the adaptation of the structural architecture, used to host a winglet morphing system, to make it accomplish the original requirements, i.e., allow the deformation values to be under the safety threshold. When facing that problem, an uncommon behavior of the finite element (FE) solver has been met: the safety factors appear to be tremendously dependent on the mesh size, so as to raise serious questions about the actual expected value, relevant for the most severe load conditions. On the other side, such singularities are more and more confined into single points (or single lines), as the mesh refines, so to evidence somehow the numerical effect behind those results. On the other side, standard engineering local methods to reduce the abovementioned strain peaks seem to work very well in re-distributing the stress and strain excesses to the whole system domain. The work does not intend to give an answer to the presented problem, being instead focused on describing its possible causes and its evident effects. Further work is necessary to detect the original source of such inconsistencies, and propose and test operative solutions. That will be the subject of the next steps of the ongoing research.

APA, Harvard, Vancouver, ISO, and other styles

26

Larson, Daniel O., Hector Neff, Donald A. Graybill, Joel Michaelsen, and Elizabeth Ambos. "Risk, Climatic Variability, and the Study of Southwestern Prehistory: An Evolutionary Perspective." American Antiquity 61, no. 2 (1996): 217–41. http://dx.doi.org/10.2307/282419.

Full text

Abstract:

Two recent developments in southwestern archaeology are brought together in this paper. First, theoreticians have begun to argue that the archaeological record should be viewed as the product of selection-driven evolution. Second, tree-ring research has produced a highly detailed history of climate for a large area of the northern Southwest. We view the record of climatic oscillations and extreme events as a record of the strength of selection favoring stabilization of specialized agricultural strategies in the arid northern Southwest. Published data from Black Mesa provide a cultural record of sufficient precision to permit comparison with the climatic record, while new data from Vermillion Cliffs, southern Utah, document one local end-product of an evolutionary sequence shaped to an important degree by the long-term variability of climate. Anasazi occupation of many regions failed to persist through the “Great Drought” of the 1270s. From a local perspective, this extreme climatic event caused adaptations shaped by selection prior to the 1270s to fail; from a broader temporal-spatial perspective, however, the drought must be seen as part of the selective regime that shaped subsequent human adaptation to the northern Southwest.

APA, Harvard, Vancouver, ISO, and other styles

27

Ghauch, Ziad Georges. "Efficient polynomial chaos approximations: Active, local and basis-adapted." ANZIAM Journal 62 (June 8, 2021): C16—C29. http://dx.doi.org/10.21914/anziamj.v62.15833.

Full text

Abstract:

Metamodels provide an efficient means for the approximation of response surfaces of systems, particularly for resource-intensive experiment designs. It is oftentimes the case that interest is focused on a specific region of the parameter space. We propose an efficient recipe for the local approximation of response surfaces using Polynomial Chaos techniques. For systems embedded in high-dimensional settings, a basis-adapted spectral representation is exploited locally for dimension reduction. The proposed approach comprises an initial heuristic global solution for parameter space exploration using an approximate global Polynomial Chaos metamodel, followed by a local design being refined through an active learning scheme. The problem of turbulent flow around a symmetric airfoil is considered. Statistical estimators based on the local, active, basis-adapted approach show less bias and faster convergence as compared to the estimators from a global solution. References B. J. Bichon, M. S. Eldred, L. P. Swiler, S. Mahadevan, and J. M. McFarland. Efficient global reliability analysis for nonlinear implicit performance functions. AIAA J. 46(10):2459–2468, 2008. doi: 10.2514/1.34321. G. E. P. Box and N. R. Draper. Empirical Model-Building and Response Surfaces. Wiley, 1987. V. Dubourg, B. Sudret, and F. Deheeger. Metamodel-based importance sampling for structural reliability analysis. Prob. Eng. Mech. 33:47–57, 2013. doi: 10.1016/j.probengmech.2013.02.002. R. G. Ghanem and P. D. Spanos. Stochastic finite element: A spectral approach. Dover, 1991. doi: 10.1007/978-1-4612-3094-6. Z. G. Ghauch. Leveraging adapted polynomial chaos metamodels for real-time Bayesian updating. J. Verif. Valid. Uncert. 4(4):041003, 2020. doi: 10.1115/1.4045693. Z. G. Ghauch, V. Aitharaju, W. R. Rodgers, P. Pasupuleti, A. Dereims, and R. G. Ghanem. Integrated stochastic analysis of fiber composites manufacturing using adapted polynomial chaos expansions. Compos. Part A: Appl. Sci. 118:179–193, 2019. doi: 10.1016/j.compositesa.2018.12.029. M. E. Johnson, L. M. Moore, and D. Ylvisaker. Minimax and maximin distance designs. J. Stat. Plan. Infer. 26(2):131–148, 1990. doi: 10.1016/0378-3758(90)90122-B. A. Notin, N. Gayton, J. L. Dulong, M. Lemaire, P. Villon, and H. Jaffal. RPCM: A strategy to perform reliability analysis using polynomial chaos and resampling. Euro. J. Comput. Mech. 19(8):795–830, 2010. doi: 10.3166/ejcm.19.795-830. OpenCFD. OpenFOAM User’s Guide. 2019. https://www.openfoam.com/documentation/user-guide. V. Picheny, D. Ginsbourger, O. Roustant, R. T Haftka, and N.-H. Kim. Adaptive designs of experiments for accurate approximation of target regions. J. Mech. Design. 132(7):071008, 2010. doi: 10.1115/1.4001873. C. Thimmisetty, P. Tsilifis, and R. Ghanem. Homogeneous chaos basis adaptation for design optimization under uncertainty: Application to the oil well placement problem. AI EDAM 31(3):265–276, 2017. doi: 10.1017/S0890060417000166. R. Tipireddy and R. Ghanem. Basis adaptation in homogeneous chaos spaces. J. Comput. Phys. 259:304–317, 2014. doi: 10.1016/j.jcp.2013.12.009. P. Tsilifis and R. G. Ghanem. Reduced Wiener chaos representation of random fields via basis adaptation and projection. J. Comput. Phys. 341:102–120, 2017. doi: 10.1016/j.jcp.2017.04.009. Turbulence Modeling Resource. NASA Langley Research Center. Washington, DC, 2018. http://turbmodels.larc.nasa.gov/.

APA, Harvard, Vancouver, ISO, and other styles

28

Urban, Mark C. "Evolution mediates the effects of apex predation on aquatic food webs." Proceedings of the Royal Society B: Biological Sciences 280, no. 1763 (2013): 20130859. http://dx.doi.org/10.1098/rspb.2013.0859.

Full text

Abstract:

Ecological and evolutionary mechanisms are increasingly thought to shape local community dynamics. Here, I evaluate if the local adaptation of a meso-predator to an apex predator alters local food webs. The marbled salamander ( Ambystoma opacum ) is an apex predator that consumes both the spotted salamander ( Ambystoma maculatum ) and shared zooplankton prey. Common garden experiments reveal that spotted salamander populations which co-occur with marbled salamanders forage more intensely than those that face other predator species. These foraging differences, in turn, alter the diversity, abundance and composition of zooplankton communities in common garden experiments and natural ponds. Locally adapted spotted salamanders exacerbate prey biomass declines associated with apex predation, but dampen the top-down effects of apex predation on prey diversity. Countergradient selection on foraging explains why locally adapted spotted salamanders exacerbate prey biomass declines. The two salamander species prefer different prey species, which explains why adapted spotted salamanders buffer changes in prey composition owing to apex predation. Results suggest that local adaptation can strongly mediate effects from apex predation on local food webs. Community ecologists might often need to consider the evolutionary history of populations to understand local diversity patterns, food web dynamics, resource gradients and their responses to disturbance.

APA, Harvard, Vancouver, ISO, and other styles

29

Ross, Howard A., and Janice L. Hawkins. "Genetic variation among local populations of jack pine (Pinus banksiana)." Canadian Journal of Genetics and Cytology 28, no. 3 (1986): 453–58. http://dx.doi.org/10.1139/g86-068.

Full text

Abstract:

Genetic variability in three jack pine (Pinus banksiana) populations, spaced 10 km apart in southern Manitoba, was analyzed electrophoretically for 15 enzymes encoded by 20 structural loci. These populations were studied as spatial and temporal controls in an investigation of the effects of long-term gamma irradiation on boreal tree species. Individual populations were, on average, polymorphic at 53.3% of the loci and had 2.0 alleles per locus. Individual trees were heterozygous at 20.7% of their loci. An F-statistic analysis revealed an overall 10% excess of heterozygotes over Hardy–Weinberg expectations. Only 2% of the genetic variation occurred among populations. Consequently Nei's genetic distance between populations was small [Formula: see text]. The amount and disposition of the genetic variation in neighbouring populations resembled that observed by others among widely spaced populations. The similarity of the genetic structure of jack pine populations at the meso- and macro-geographic levels might result from the antagonistic effects of long distance gene flow via pollen transport (increasing homogeneity) and adaptation to fire or other patchily distributed environmental factors (reducing homogeneity).Key words: Jack pine, Pinus banksiana, allozymic variation, genetic structure.

APA, Harvard, Vancouver, ISO, and other styles

30

Tarasov, Vladimir. "SOCIAL VALUES OF SPORTS MOVEMENT AND PREVENTION OF MIGRANTOPHOBIA." Vestnik Majkopskogo Gosudarstvennogo Tehnologiceskogo Universiteta 13, no. 2 (2021): 123–28. http://dx.doi.org/10.47370/2078-1024-2021-13-2-123-128.

Full text

Abstract:

The modern world and Russia in particular is characterized by intensive migration processes. Ethnic, socio-cultural, religious conflicts and migrant-phobia are spreading in the countries that receive migrants. This requires a search for new means and mechanisms for the adaptation and integration of migrants, as well as the prevention of migrant phobia among the local population. The aim of the study is to give a sociological description of migrantophobia in Russia and substantiate the potential of the social values of the sports movement in its prevention. The content of the research is based on: 1) the analysis of bibliographic sources on the topic of the article; 2) a secondary analysis of sociological research on the perception of migrants and migrant phobia. Sociological studies demonstrate a downward trend in the level of migrantophobia in the Russian society, however, there is a need for new ways of preventing it. It has been concluded that sport as a social institution and such social values of sport as activity, self-realization, communication, respect, friendship, tolerance can play a significant role in the adaptation and integration of migrants, as well as in prevention of migrant phobia among the local population. Interpretations of the social functions of sports in relation to migrants have been given. The macro-, meso- and micro factors of the involvement of migrants in sports have been indicated.

APA, Harvard, Vancouver, ISO, and other styles

31

Musaad, Muhammad, and Hariman Dahrif. "Dampak Program Pemberdayaan Ekonomi Lokal terhadap Perubahan Sosial Ekonomi Masyarakat Adat di Kabupaten Biak Numfor." Studia Komunika: Jurnal Ilmu Komunikasi 3, no. 2 (2020): 16–23. http://dx.doi.org/10.47995/jik.v1i1.6.

Full text

Abstract:

Abstrak Penelitian ini bertujuan untuk memahami dan menjelaskan perubahan sosial dan ekonomi masyarakat adat, dari respons penerimaanhinggapelaksanaan program pemberdayaan ekonomi lokal di Kabupaten Biak Numfor.Analisis menggunakan paradigma fenomonologi, pendekatan kualitatif, dengan pola pikir induktif-deduktif, atau induktif abstraktif. Analisis datanya dilakukan melalui analisis Spradely meliputi tema-tema domain yang diabstraksi dari lapangan, analisis komponensial dan tema kultural. Pendalaman kajian ditempuh dengan analisis konten serta teknik triangulasi. Hasilnya adalah perubahan sosial ekonomi mengarah pada dua kecenderungan, yaitu: pertama; keinginan mengintegrasikan usaha yang dipicu oleh etos kerja subsisten produktif,dan kedua; menjadikan bantuan-bantuan tersebut sebagai mata pencaharian bahkan konsumtif, menghasilkan etos kerja subsisten konsumtif. Namun, akibat pemaksaan (coertion) yang dilakukan oleh pelaksana dalam mengimplementasikan program tersebut, masyarakat adat pada tingkat lokal (mikro) melakukan “penyesuaian diri” (self-adaptation). Pada tingkat regional (meso dan makro) dalam hal mengembangkan usaha, memperluas distribusi dan akses pemasaran masyarakat adat mengalami “penyesuian hidup” (life conditional) dengan berbagai kebijakan yang belum disentuh oleh pelaksana (aktor) dan program pemberdayaan ekonomi lokal selama ini.

APA, Harvard, Vancouver, ISO, and other styles

32

Le Roy, Benjamin, Aude Lemonsu, and Robert Schoetter. "A statistical–dynamical downscaling methodology for the urban heat island applied to the EURO-CORDEX ensemble." Climate Dynamics 56, no. 7-8 (2021): 2487–508. http://dx.doi.org/10.1007/s00382-020-05600-z.

Full text

Abstract:

AbstractRegional Climate Models (RCMs) are the primary climate information available to public stakeholders and city-planners to support local adaptation policies. However, with resolution in the order of ten kilometres, RCMs do not explicitly represent cities and their influence on local climate (e.g. Urban Heat Island; UHI). Downscaling methods are required to bridge the gap between RCMs and city scale. A statistical–dynamical downscaling methodology is developed to quantify the UHI of the city of Paris (France), based on a Local Weather Types (LWTs) classification combined with short-term high-resolution (1-km) urban climate simulations. The daily near-surface temperature amplitude, specific humidity, precipitation, wind speed and direction simulated by the RCMs are used for the LWTs attribution. The LWTs time series is associated to randomly selected days simulated with the mesoscale atmospheric model Meso-NH coupled to the urban canopy model Town Energy Balance to calculate the UHI corresponding to the successive LWTs. The downscaling methodology is applied to the EURO-CORDEX ensemble driven by the ERA-Interim reanalysis, and evaluated for the 2000–2008 period against station observations and a 2.5-km reanalysis. The short-term dynamical simulations slightly underestimate and overestimate near-surface minimum and maximum air temperature respectively, but capture the UHI intensity with biases in the order of a tenth of a degree. RCMs show significant differences in the variables used for the LWTs attribution, but the seasonal LWT frequencies are captured. Consequently, the reconstructed temperature fields maintain the small biases of the Meso-NH simulations and the statistical–dynamical downscaling greatly improves the UHI compared to the raw data of RCMs.

APA, Harvard, Vancouver, ISO, and other styles

33

Fratini, C. F., M. Elle, M. B. Jensen, and P. S. Mikkelsen. "A conceptual framework for addressing complexity and unfolding transition dynamics when developing sustainable adaption strategies in urban water management." Water Science and Technology 66, no. 11 (2012): 2393–401. http://dx.doi.org/10.2166/wst.2012.442.

Full text

Abstract:

To achieve a successful and sustainable adaptation to climate change we need to transform the way we think about change. Much water management research has focused on technical innovation with a range of new solutions developed to achieve a ‘more sustainable and integrated urban water management cycle’. But Danish municipalities and utility companies are struggling to bring such solutions into practice. ‘Green infrastructure’, for example, requires the consideration of a larger range of aspects related to the urban context than the traditional urban water system optimization. There is the need for standardized methods and guidelines to organize transdisciplinary processes where different types of knowledge and perspectives are taken into account. On the basis of the macro–meso–micro pattern inspired by complexity science and transition theory, we developed a conceptual framework to organize processes addressing the complexity characterizing urban water management in the context of climate change. In this paper the framework is used to organize a research process aiming at understanding and unfolding urban dynamics for sustainable transition. The final goal is to enable local authorities and utilities to create the basis for managing and catalysing the technical and organizational innovation necessary for a sustainable transition towards climate change adaptation in urban areas.

APA, Harvard, Vancouver, ISO, and other styles

34

Schoetter, Robert, Julia Hidalgo, Renaud Jougla, Valéry Masson, Mario Rega, and Julien Pergaud. "A Statistical–Dynamical Downscaling for the Urban Heat Island and Building Energy Consumption—Analysis of Its Uncertainties." Journal of Applied Meteorology and Climatology 59, no. 5 (2020): 859–83. http://dx.doi.org/10.1175/jamc-d-19-0182.1.

Full text

Abstract:

AbstractHigh-resolution maps of the urban heat island (UHI) and building energy consumption are relevant for urban planning in the context of climate change mitigation and adaptation. A statistical–dynamical downscaling for these parameters is proposed in the present study. It combines a statistical local weather type approach with dynamical simulations using the mesoscale atmospheric model Meso-NH coupled to the urban canopy model Town Energy Balance. The downscaling is subject to uncertainties related to the weather type approach (statistical uncertainty) and to the numerical models (dynamical uncertainty). These uncertainties are quantified for two French cities (Toulouse and Dijon) for which long-term dense high-quality observations are available. The seasonal average nocturnal UHI intensity is simulated with less than 0.2 K bias for Dijon, but it is overestimated by up to 0.8 K for Toulouse. The sensitivity of the UHI intensity to weather type is, on average, captured by Meso-NH. The statistical uncertainty is as large as the dynamical uncertainty if only one day is simulated for each weather type. It can be considerably reduced if 3–6 days are taken instead. The UHI reduces the building energy consumption by 10% in the center of Toulouse; it should therefore be taken into account in the production of building energy consumption maps.

APA, Harvard, Vancouver, ISO, and other styles

35

Vlados, Charis, and Dimos Chatzinikolaou. "Thoughts on Competitiveness and Integrated Industrial Policy: A Field of Mutual Convergences." Research in World Economy 11, no. 3 (2020): 12. http://dx.doi.org/10.5430/rwe.v11n3p12.

Full text

Abstract:

Competitiveness and industrial policy seem to play a critical role in the development and mutation of different spatialized socio-economic systems. This article aims to review the literature on these two concepts and suggest a novel theoretical framework. First, we identify that, in the relevant literature, industrial policy acquires progressively a repositioned content, described as a new, holistic, multidimensional, or integrated policy that can help create and sustain the competitiveness of the firms, industries, localities, nations, or other socio-economic agglomerations. In this context, we explore the form of an actual integrated industrial policy and propose the theoretical framework of the competitiveness web, in which the co-evolution of micro-meso-macro levels are explored, by placing the dynamics of business innovation at the dialectic center of the overall developmental process. This integrated industrial policy to strengthen competitiveness must also be able to promote innovation in the different local and regional ecosystems and, therefore, we conceive a policy mechanism in the form of the Institutes of Local Development and Innovation (ILDI). The primary purpose of these institutes is to diagnose and strengthen the Stra.Tech.Man physiology (strategy-technology-management synthesis) of the local socio-economic organizations. We believe that this new approach to the integrated industrial policy to strengthen the local competitiveness can contribute to facilitating the adaptation of the socio-economic systems, and especially the less dynamic and developed, to the new emerging challenges of the crisis and restructuring of globalization in the pandemic era.

APA, Harvard, Vancouver, ISO, and other styles

36

Tajuddin, Nilofer, and Marcin Dąbrowski. "Enabling Socio-Ecological Resilience in the Global South: Insights from Chennai, India." Sustainability 13, no. 19 (2021): 10522. http://dx.doi.org/10.3390/su131910522.

Full text

Abstract:

Addressing climate change adaptation in the cities of the Global South is crucial as they are the most at risk and, arguably, the least capable of coping with it due to their rapid expansion, informal development, and limited institutional capacity. This paper explores this challenge in the case of Chennai, India, a city which, in recent years, has faced several climate related disasters, including floods. Building on an innovative combination of research methods (policy documents analysis, stakeholder interviews, and a community workshop), the study analyses the barriers and explores potentials for operationalising socio-ecological resilience in Chennai in the face of an ongoing conflict between rapid urbanisation and the natural water system, compromising the region’s hydrological capacity and resilience to flooding. In particular, drawing on the notion of evolutionary resilience and multi-level approach, the paper investigates (1) the scope for developing an integrated vision for resilience of the Chennai region (macro level); (2) the presence and the capacity of institutions to connect the different stakeholders and mediate their interests (meso level); and (3) the barriers and potentials developing local adaptation strategies in a bottom-up manner (micro level). The study sheds light on the under-researched issue of socio-ecological resilience in Chennai, while identifying potentials for implementing it through a combination of top down and bottom-up approaches, which in turn provides useful lessons for planning for resilience in other cities in the Global South.

APA, Harvard, Vancouver, ISO, and other styles

37

Rueter, Jana, Susanne Brandstetter, Janina Curbach, Verena Lindacher, Berit Warrelmann, and Julika Loss. "How Older Citizens in Germany Perceive and Handle Their Food Environment—A Qualitative Exploratory Study." International Journal of Environmental Research and Public Health 17, no. 19 (2020): 6940. http://dx.doi.org/10.3390/ijerph17196940.

Full text

Abstract:

Apart from individual factors like knowledge or personal motivation, the environment also influences a person’s eating behaviour. Food environments can be described as the collective physical, economic, policy and sociocultural surroundings, opportunities and conditions that influence people’s food choices and nutritional status. In order to explore how older citizens in rural Germany perceive and handle their food environment, we conducted semi-structured face-to-face interviews with 35 older adults (71 ± 7 years), asking about micro-, meso- and macro-level influences on eating habits. Participants reported social factors to be crucial in shaping their diets, such as preferences of family members or social expectations connected to roles (guest, host). On a physical level, structural aspects and resources in their nearby surroundings influenced shopping and eating behaviour (for example access to an own vegetable garden, local shopping facilities and restaurants). Macro-level influences such as the food industry were hardly mentioned. Participants noticed that the environment affects their diets but dealt with undesired influences using strategies of adaptation and behaviour change, rather than challenging the environmental influences. Public health projects should raise the awareness of the multiple environmental influences on eating behaviour and also help people to create healthier food environments.

APA, Harvard, Vancouver, ISO, and other styles

38

Funk, Charles, and Len J. Treviño. "Institution building in retreat." Cross Cultural & Strategic Management 24, no. 3 (2017): 436–53. http://dx.doi.org/10.1108/ccsm-01-2016-0001.

Full text

Abstract:

Purpose The purpose of this paper is to describe co-devolutionary processes of multinational enterprise (MNE)/emerging economy institutional relationships utilizing concepts from “old” institutional theory as well as the institutional aspects of socially constructed realities. Design/methodology/approach The authors develop a set of propositions that explore the new concept of a co-devolutionary relationship between MNEs and emerging economy institutions. Guided by prior research, the paper investigates MNE/emerging economy institutional co-devolution at the macro-(MNE home and host countries), meso-(MNE industry/host country regulative and normative institutions) and micro-(MNE and host country institutional actors) levels. Findings MNE/emerging economy institutional co-devolution occurs at the macro-level via negative public communications in the MNE’s home and host countries, at the meso-level via host country corruption and MNE adaptation, and at the micro-level via pressures for individual actors to cognitively “take for granted” emerging economy corruption, leading to MNE divestment and a reduction in new MNE investment. Research limitations/implications By characterizing co-devolutionary processes within MNE/emerging economy institutional relationships, the research augments co-evolutionary theory. It also assists in developing more accurate specification and measurement methods for the organizational co-evolution construct by using institutional theory’s foundational processes to discuss MNE/emerging economy institutional co-devolution. Practical implications The research suggests the use of enhanced regulation, bilateral investment treaties and MNE/local institution partnerships to stabilize MNE/emerging economy institutional relationships, leading to more robust progress in building emerging economy institutions. Originality/value The research posits that using the concepts of institutional theory as a foundation provides useful insights into the “stickiness” of institutional instability and corruption in emerging economies and into the resulting co-devolutionary MNE/emerging economy institutional relationships.

APA, Harvard, Vancouver, ISO, and other styles

39

Greenes, R. "“Desktop Knowledge”: A New Focus for Medical Education and Decision Support." Methods of Information in Medicine 28, no. 04 (1989): 332–39. http://dx.doi.org/10.1055/s-0038-1636780.

Full text

Abstract:

Abstract:Physicians today are faced with “data overload” and, paradoxically, “information underload” - the inability to locate pertinent, needed knowledge in a sea of data with which they are inundated. Increasingly, the professional functions of the physician are becoming focused on the desktop workstation, in terms of its ability to provide “windows” into local databases and knowledge resources, and to serve as an. access port to other networked resources. A challenge we now face is to develop means for structuring the vast potentially available knowledge resources in such a manner that access to pertinent knowledge can be facilitated, and to develop acceptable interfaces to the knowledge resources so that a user can effectively navigate through them. The complexity of this task is due to the nature of the knowledge resources - knowledge can be in a variety of forms; ranging from textual and pictorial material, to structured representations, to more dynamic embodiments in the form of procedures. In the Decision Systems Group we have focused on the development of a prototype desktop knowledge management environ- . ment known as Explorer-2, with the objective of providing a consistent interface for access to a wide variety of knowledge. Our accomplishments to date encompass the incorporation into the Explorer-2 environment of adaptations of textbook chapters and books, image data bases, simulations, and expert systems. Navigational aids are provided by a semantic net browser using both MeSH and augmented taxonomies and by a graphical overview map. User response to the predecessor system, Explorer-1, has been strongly positive. Our experience to date suggests a number of observations about the characteristics that knowledge management systems should possess, and the next steps for further research and development.

APA, Harvard, Vancouver, ISO, and other styles

40

Repke, Lydia, and Verónica Benet-Martínez. "The (Diverse) Company You Keep: Content and Structure of Immigrants’ Social Networks as a Window Into Intercultural Relations in Catalonia." Journal of Cross-Cultural Psychology 49, no. 6 (2018): 924–44. http://dx.doi.org/10.1177/0022022117733475.

Full text

Abstract:

This research examines how the social networks of immigrants residing in a European bicultural and bilingual context (Catalonia) relate to levels of adjustment (both psychological and sociocultural) and to bicultural identity integration (BII). Moroccan, Pakistani, Ecuadorian, and Romanian immigrants residing in Barcelona nominated 25 individuals (i.e., alters) from their habitual social networks and provided demographic (e.g., ethnicity), relationship type (e.g., family, friend, neighbor), and structural (who knew whom) information for each of these alters. Even after controlling for individual-level demographic and acculturation variables, the content and structure of immigrants’ personal social networks had unique associations with both types of adjustment and with BII. Specifically, the overall degree of cultural diversity in the network and the amount of Catalan (but not Spanish) “weak” ties (i.e., acquaintances, colleagues, neighbors) positively predicted these outcomes. Amount of interconnectedness between local coethnic and Catalan/Spanish alters also predicted sociocultural adjustment and BII positively. Finally, against a “culture and language similarity” hypothesis, Moroccan and Pakistani participants had social networks that were more culturally integrated, relative to Ecuadorians and Romanians. Results from this study attest to the importance of examining actual intercultural relations and going beyond individuals’ reported acculturation preferences to understand immigrants’ overall adaptation and cultural identity dynamics. Furthermore, results highlight the interplay between interculturalism experienced at the intrapersonal, subjective level (i.e., BII), and at the meso-level (i.e., having culturally diverse networks that also include interethnic ties among alters).

APA, Harvard, Vancouver, ISO, and other styles

41

DAVYDENKO, Vladimir A., Elena V. ANDRIANOVA, and Marina V. KHUDYAKOVA. "CONTEMPORARY WORLD CONTEXTS OF RURAL SOCIOLOGY IN THE RUSSIAN RURAL LIFE REALITIES." Tyumen State University Herald. Social, Economic, and Law Research 6, no. 3 (2020): 79–129. http://dx.doi.org/10.21684/2411-7897-2020-6-3-79-129.

Full text

Abstract:

This article critically introduces the sociology of rural areas through rethinking and reinterpreting contemporary world contexts of rural sociology and factual representation of the Russian rural life, applying qualitative methods of analyzing in-depth interviews with Tyumen Region’s south residents. The authors employ theoretical and methodological approaches, mainly used in classical and modern academic literature on rural realities. The scientific approach of this article, alternative to the popular perspectives of political economy and sociology of postmodernism, is based on compounding the interactionist theory and social constructionism with economic sociology, and relies on the growing status of qualitative methods used not only in rural sociology, but also in social geography. The case studies on contemporary rural life problems provide the foundation for discussion and criticism. This article also presents the first results of 2020 field research within the framework of a project aimed at studying institutional factors and forms of Tyumen Region south rural areas development. The authors prove the importance of assessing current problems and functioning prospects of the two most important Russian countryside social institutions — the local (municipal) government and business/entrepreneurship, which are considered through the dominant scenarios of their interests’ interaction with reproduction, preservation, and sustainability of rural areas. The authors’ conclusions are drawn from theoretical and empirical results of generalization and conceptualization of rural life peculiarities, considered through the prism of sociological theories of the countryside and world contexts of this scientific field. This article focuses on illustrating rural areas adaptability and versatility to many external shocks, as well as on contributing to the discussion of the current challenges, problems and opportunities that are opening for rural sociology in the realities of modern Russian rural life. Recommendations, stemming from the current world agenda of rural sociology, propose a relatively new concept of rural politics, displaying the “placed-based” paradigm. The paradigm is to reduce the inequality and inefficiency in agricultural production by removing barriers and seeking opportunities in given locations (villages and small towns), especially those which lag behind more dynamic territories in key resources. In other words, these are the “territories of growth” (an increase in population density and yield, expansion or small reduction of farmland); “territories of stagnation” (a decrease in population density, farmland and yield); and “territories of contraction” (a decrease in population with a significant reduction in farmland and yield). However, even for these highly generalized socio-spatial characteristics, there is only approximate information that does not allow classifying the scenarios of rural regions reproduction. Spatial dimension indicates the diversity principle of economic change and development. Adaptation of programs to eliminate disadvantages and enhance strengths of territories is likely to help achieving a high return on investment in rural policy through grants, loans, subsidies, subventions (State Program 2020-2025). Placed-based policies should have the greatest impact on lagging regions, reducing regional inequalities, facilitating regional convergence of rural areas. The concept of “territories of growth — stagnation — contraction” is not yet verified by large studies. Theoretical grounding of placed-based policies, originates from economic concepts, broadening them with spatial, cultural, social and institutional dimensions. There is evidence that the placed-based strategy will advance lagging regions and boost the country’s economy. A social policy based on this concept can be a tool for rural areas development, ensuring the complementarity between efficiency and equity. The scientific novelty of this research lies in the development of a conceptual-categorical scheme that demonstrates the interaction of various branches of government, agricultural actors of different levels and entrepreneurs as a result of their interests coordination. The interaction is presented in a form of impact that macro-actors have on micro- and meso- subjects at the local level, which is very important for tracking the formal-informal ratio in rural residents’ lives.

APA, Harvard, Vancouver, ISO, and other styles

42

Jackson, Charles W., Christopher J. Roy, and Christopher R. Schrock. "Truncation Error Based Mesh Optimization." Journal of Verification, Validation and Uncertainty Quantification 5, no. 4 (2020). http://dx.doi.org/10.1115/1.4049038.

Full text

Abstract:

Abstract Truncation error is used to drive mesh adaptation in order to reduce the discretization error in solutions to a variety of 1D and 2D flow problems. The adaptation is performed using r-adaptation to move the mesh nodes in the domain in an attempt to reduce the truncation error since it is the local source of discretization error. Here, we present a new set of r-adaptation methods called mesh optimization along with three different ways of performing this type of adaptation. Each of these techniques uses a finite difference gradient-based local optimization technique with different sets of design variables to create a mesh that minimizes a functional based on truncation error. These new truncation error based mesh optimization techniques are compared to a more common truncation error based mesh equidistribution technique. Some observations on the performance and behavior of the different adaptation methods and best practices for their use are presented. All of the optimization methods are shown to reduce the truncation error one or two orders of magnitude and the discretization error by roughly one order of magnitude for the 1D problems tested. In two dimensions, the optimization-based adaptation methods are able to reduce the discretization error by up to a factor of seven. Mesh equidistribution achieved similar levels of improvement for much less cost compared to the mesh optimization techniques.

APA, Harvard, Vancouver, ISO, and other styles

43

Bono, G., and A. M. Awruch. "A MESH ADAPTION METHOD BY NODE RE-ALLOCATION USING AN EDGE-BASED ERROR MEASURE." Revista de Engenharia Térmica 4, no. 2 (2005). http://dx.doi.org/10.5380/ret.v4i2.5416.

Full text

Abstract:

A mesh adaptation technique implemented in an algorithm to simulate compressible flows characterized by the presence of strong shocks, using the finite element method (FEM), is presented in this work. The initial mesh is continuously adapted during the solution process using a node movement technique, keeping as much as possible mesh smoothness and local orthogonality with an unconstrained optimization method. The error is estimated as a function of the Hessian tensor, containing second derivatives of the specific mass, and a Riemann metric projected on the element edges is obtained in order to determine node movements. Time and spatial discretization of the governing equations are carried out using an explicit Taylor-Galerkin scheme and an isoparametric hexahedrical element with eight nodes. An Arbitrary Lagrangean Eulerian (ALE) description is used to take into account mesh movement. Finally, some two-dimensional examples involving transonic and supersonic flows are presented to validate the algorithm.

APA, Harvard, Vancouver, ISO, and other styles

44

Parseliunas, A., S. Paskauskas, V. Simatoniene, J. Vaitekunas, and D. Venskutonis. "Adaptation and validation of the Carolinas Comfort Scale: a questionnaire-based cross-sectional study." Hernia, March 29, 2021. http://dx.doi.org/10.1007/s10029-021-02399-4.

Full text

Abstract:

Abstract Purpose Quality of life (QoL) is an important outcome following surgery. The Carolinas Comfort scale (CCS) is a specific questionnaire used to evaluate QoL in patients who underwent abdominal hernia repair with mesh. The aim of this study was to create a Lithuanian version of the CCS. Methods A questionnaire-based cross-sectional study was conducted. A Lithuanian version of the CCS was created by translating the original questionnaire in accordance with the guidelines. The Lithuanian questionnaire was provided to hernia patients at 1 week and at 1 month postoperatively. The main validation characteristics of the Lithuanian CCS were assessed and compared to the original version. Results The complete response rate of patients was close to 90%. Internal consistency was excellent, with a Cronbach’s α of 0.953. Correlation coefficients ranged from 0.361 to 0.703 in the test–retest analysis. In the construct validity analysis, the strongest correlations were observed in the domains of physical functioning and bodily pain (− 0.655 and − 0.584, respectively) and the weakest correlations in role-emotional and mental health (− 0.268 and − 0.230, respectively). The mean scores of all CCS domains and the total score for satisfied patients were significantly lower (p < 0.001) than those of dissatisfied patients. The principal component analysis identified 3 components, with the first accounting for 56% of the variance. Conclusions The Lithuanian version of CCS maintains the original validity and is a reliable and valid tool for assessing specific QoL factors after the repair of inguinal hernia with mesh. We recommend using this CCS version in personal, local, and international contexts.

APA, Harvard, Vancouver, ISO, and other styles

45

Dobrzynski, Cécile, Pascal Frey, and Olivier Pironneau. "Couplage et adaptation de maillage anisotrope pour des simulations de flux d’air dans des géométries complexes." European Journal of Computational Mechanics, August 16, 2007, 749–73. http://dx.doi.org/10.13052/remn.16.749-773.

Full text

Abstract:

The numerical simulation of air flow in a building or a house is certainly a very challenging field of engineering applications. The objectives differ from one application to the other, ranging from the optimization of air conditioning systems in buildings to the study of the propagation of harmful products via the air conditioning system. In this paper, we address the problem of coupling the Navier-Stokes equations for incompressible fluids and a temperature equation. To solve this problem in 3d, we use an anisotropic mesh adaptation strategy. The meshes are generated by a local remeshing techniques based on an anisotropic version of Delaunay kernel. The method is fairly general and applies to other cases as well. We illustrate this problem with an example showing the heating of the last floor of a furnished house.

APA, Harvard, Vancouver, ISO, and other styles

46

Govindarajan, V., H. S. Udaykumar, and K. B. Chandran. "Two-Dimensional Simulation of Flow and Platelet Dynamics in the Hinge Region of a Mechanical Heart Valve." Journal of Biomechanical Engineering 131, no. 3 (2008). http://dx.doi.org/10.1115/1.3005158.

Full text

Abstract:

The hinge region of a mechanical bileaflet valve is implicated in blood damage and initiation of thrombus formation. Detailed fluid dynamic analysis in the complex geometry of the hinge region during the closing phase of the bileaflet valve is the focus of this study to understand the effect of fluid-induced stresses on the activation of platelets. A fixed-grid Cartesian mesh flow solver is used to simulate the blood flow through a two-dimensional geometry of the hinge region of a bileaflet mechanical valve. Use of local mesh refinement algorithm provides mesh adaptation based on the gradients of flow in the constricted geometry of the hinge. Leaflet motion is specified from the fluid-structure interaction analysis of the leaflet dynamics during the closing phase from a previous study, which focused on the fluid mechanics at the gap between the leaflet edges and the valve housing. A Lagrangian particle tracking method is used to model and track the platelets and to compute the magnitude of the shear stress on the platelets as they pass through the hinge region. Results show that there is a boundary layer separation in the gaps between the leaflet ear and the constricted hinge geometry. Separated shear layers roll up into vortical structures that lead to high residence times combined with exposure to high-shear stresses for particles in the hinge region. Particles are preferentially entrained into this recirculation zone, presenting the possibility of platelet activation, aggregation, and initiation of thrombi.

APA, Harvard, Vancouver, ISO, and other styles

47

Hupkes, H. J., and E. S. Van Vleck. "Travelling Waves for Adaptive Grid Discretizations of Reaction Diffusion Systems II: Linear Theory." Journal of Dynamics and Differential Equations, March 6, 2021. http://dx.doi.org/10.1007/s10884-021-09942-y.

Full text

Abstract:

AbstractIn this paper we consider an adaptive spatial discretization scheme for the Nagumo PDE. The scheme is a commonly used spatial mesh adaptation method based on equidistributing the arclength of the solution under consideration. We assume that this equidistribution is strictly enforced, which leads to the non-local problem with infinite range interactions that we derived in Hupkes and Van Vleck (J Dyn Differ Equ 28:955, 2016). For small spatial grid-sizes, we establish some useful Fredholm properties for the operator that arises after linearizing our system around the travelling wave solutions to the original Nagumo PDE. In particular, we perform a singular perturbation argument to lift these properties from the natural limiting operator. This limiting operator is a spatially stretched and twisted version of the standard second order differential operator that is associated to the PDE waves.

APA, Harvard, Vancouver, ISO, and other styles

48

Azimaee, Mahmoud, J. Charles Victor, Marian Vermeulen, and Mark Smith. "A National Concept Dictionary." International Journal of Population Data Science 3, no. 4 (2018). http://dx.doi.org/10.23889/ijpds.v3i4.709.

Full text

Abstract:

Overall objectives or goalMost of the organizations that use population administrative data for research purposes have internal repository of validated definitions and algorithms of their own. Many of these concepts and definitions are applicable or at least adaptable to other organizations and jurisdictions. A comprehensive National (and potentially International) Concept Dictionary could help investigators to carry out methodologically sound work using consistent and validated algorithms using a shared pool of knowledge and resources. The Institute for Clinical Evaluative Sciences (ICES) in Ontario, Canada has recently modernized its internal Concept Dictionary by adopting standard templates based on the Manitoba Centre for Health Policy (MCHP) Concept Dictionary, reviewing and updating existing content and tagging the concept entries with appropriate MeSH terms and data sources, and adding standard computer code (e.g., SAS coding) where appropriate. A SharePoint® web-based application has been developed to provide advanced tagging, searching and browsing features. We envision a wiki-based Concept Dictionary hosted on a cloud-based environment with very granular access controls to provide enough flexibility for each participating organization to control their own content. This means each organization will be able to decide on how to share their own concepts (or part of them) with the public or internal users. All content will be tagged with MeSH terms and as well with the organization’s name that initially posts each entry. Other organizations which find the same concept applicable to their own use can tag the same entry with their organization name or refer to a secondary adapted entry if adaptation to fit their data and methodologies is required. The Search feature will allow refining the search criteria by MeSH terms, data sources, and also organization/jurisdiction name. Multiple layers of access controls will allow each organization to have their own groups of users with different standard privileges such as Local Administrators, Authors and Approvers (or Publishers). The Approver (Publisher) users within each organization can publish each entry for internal or public view. This way, for example, a definition/algorithm can be viewable only within the organization until the validation process is complete, and then the entry can be made publically available, while some sections, such as computer code, can remain restricted to the organization. We will discuss challenges in developing and maintaining such a platform including the costs, governance, intellectual property rights, copyrights and liabilities for the participating organizations. The intended output or outcomeWe aim to use this opportunity to form a working group from the interested organizations that are ready to participate and commit in developing this collaborative platform. After the conference, there will be follow up sessions with the members of the working group to plan and develop the online application.

APA, Harvard, Vancouver, ISO, and other styles

49

Windle, Alice, Sara Javanparast, Toby Freeman, and Fran Baum. "Assessing organisational capacity for evidence-informed health policy and planning: an adaptation of the ORACLe tool for Australian primary health care organizations." Health Research Policy and Systems 19, no. 1 (2021). http://dx.doi.org/10.1186/s12961-021-00682-5.

Full text

Abstract:

Abstract Background Many nations have established primary health care (PHC) organizations that conduct PHC planning for defined geographical areas. The Australian Government established Primary Health Networks (PHNs) in 2015 to develop and commission PHC strategies to address local needs. There has been little written about the capacity of such organizations for evidence-informed planning, and no tools have been developed to assess this capacity, despite their potential to contribute to a comprehensive effective and efficient PHC sector. Methods We adapted the ORACLe tool, originally designed to examine evidence-informed policy-making capacity, to examine organizational capacity for evidence-informed planning in meso-level PHC organizations, using PHNs as an example. Semi-structured interviews were conducted with 14 participants from five PHNs, using the ORACLe tool, and scores assigned to responses, in seven domains of capacity. Results There was considerable variation between PHNs and capacity domains. Generally, higher capacity was demonstrated in regard to mechanisms which could inform planning through research, and support relationships with researchers. PHNs showed lower capacity for evaluating initiatives, tools and support for staff, and staff training. Discussion and conclusions We critique the importance of weightings and scope of some capacity domains in the ORACLe tool. Despite this, with some minor modifications, we conclude the ORACLe tool can identify capacity strengths and limitations in meso-level PHC organizations. Well-targeted capacity development enables PHC organizations’ strategies to be better informed by evidence, for optimal impact on PHC and population health outcomes.

APA, Harvard, Vancouver, ISO, and other styles

50

Behan, Jamie, Bai Li, and Yong Chen. "Examining Scale Dependent Environmental Effects on American Lobster (Homarus americanus) Spatial Distribution in a Changing Gulf of Maine." Frontiers in Marine Science 8 (July 7, 2021). http://dx.doi.org/10.3389/fmars.2021.680541.

Full text

Abstract:

The Gulf of Maine (GOM) is a highly complex environment and previous studies have suggested the need to account for spatial nonstationarity in species distribution models (SDMs) for the American lobster (Homarus americanus). To explore impacts of spatial nonstationarity on species distribution, we compared models with the following three assumptions : (1) large-scale and stationary relationships between species distributions and environmental variables; (2) meso-scale models where estimated relationships differ between eastern and western GOM, and (3) finer-scale models where estimated relationships vary across eastern, central, and western regions of the GOM. The spatial scales used in these models were largely determined by the GOM coastal currents. Lobster data were sourced from the Maine-New Hampshire Inshore Bottom Trawl Survey from years 2000–2019. We considered spatial and environmental variables including latitude and longitude, bottom temperature, bottom salinity, distance from shore, and sediment grain size in the study. We forecasted distributions for the period 2028–2055 using each of these models under the Representative Concentration Pathway (RCP) 8.5 “business as usual” climate warming scenario. We found that the model with the third assumption (i.e., finest scale) performed best. This suggests that accounting for spatial nonstationarity in the GOM leads to improved distribution estimates. Large-scale models revealed a tendency to estimate global relationships that better represented a specific location within the study area, rather than estimating relationships appropriate across all spatial areas. Forecasted distributions revealed that the largest scale models tended to comparatively overestimate most season × sex × size group lobster abundances in western GOM, underestimate in the western portion of central GOM, and overestimate in the eastern portion of central GOM, with slightly less consistent and patchy trends amongst groups in eastern GOM. The differences between model estimates were greatest between the largest and finest scale models, suggesting that fine-scale models may be useful for capturing effects of unique dependencies that may operate at localized scales. We demonstrate how estimates of season-, sex-, and size- specific American lobster spatial distribution would vary based on the spatial scale assumption of nonstationarity in the GOM. This information may help develop appropriate local adaptation measures in a region that is susceptible to climate change.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Local Mesh Adaptation'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles