Soft computing applications in dynamic model identification of polymer extrusion process

This paper proposes the application of soft computing to deal with the constraints in conventional modelling techniques of the dynamic extrusion process. The proposed technique increases the efficiency in utilising the available information during the model identification. The resultant model can be classified as a ‘grey-box model’ or has been termed as a ‘semi-physical model’ in the context. The extrusion process contains a number of parameters that are sensitive to the operating environment. Fuzzy ruled-based system is introduced into the analytical model of the extrusion by means of sub-models to approximate those operational-sensitive parameters. In drawing the optimal structure for the sub-models, a hybrid algorithm of genetic algorithm with fuzzy system (GA-Fuzzy) has been implemented. The sub-models obtained show advantages such as linguistic interpretability, simpler rule-base and less membership functions. The developed model is adaptive with its learning ability through the steepest decent error back-propagation algorithm. This ability might help to minimise the deviation of the model prediction when the operational-sensitive parameters adapt to the changing operating environment in the real situation. The model is first evaluated through simulations on the consistency of model prediction to the theoretical analysis. Then, the effectiveness of adaptive sub-models in approximating the operational-sensitive parameters during the operation is further investigated

Area, climate heterogeneity, and the response of climate niches to ecological opportunity in island radiations of Anolis lizards

Aim Rates of climate niche evolution underlie numerous fundamental ecological processes and patterns. However, while climate niche conservatism varies markedly among regions and clades, the source of this variation remains poorly understood. We tested whether ecological opportunity can stimulate radiation within climate niche space at biogeographic scales, predicting that rates of climate niche evolution will scale with geographic area and climate heterogeneity. Location Caribbean Methods We quantified two temperature axes (mean temperature and temperature seasonality of species' localities) of the climate niche for 130 Anolis species on Cuba, Hispaniola, Puerto Rico, Jamaica and the northern and southern Lesser Antilles. Using a species-level phylogeny, we fitted macroevolutionary models that either constrained rates of climate niche evolution or allowed them to vary among regions. Next, we regressed region-specific evolutionary rates against area, species richness and climate heterogeneity. We evaluated whether results were robust to uncertainty in phylogenetic and biogeographic reconstructions and the assumed mode of evolution. Results For both niche axes, an Ornstein-Uhlenbeck model that allowed the net rate of evolution (σ2) to vary among island groups fit the data considerably better than a single-rate Brownian motion model. Nagelkerke pseudo-R2 values of the fit of these OU models to mean temperature and seasonality axes were 0.43 and 0.66, respectively. Evolutionary rates for both axes were higher in larger areas, which also have more species. Only the rate of mean occupied temperature evolution was positively related to climate heterogeneity, and only after accounting for region size. Conclusions Rates of climate niche evolution scale consistently with the area available for radiation, but responses to climate heterogeneity vary among niche axes. For the mean temperature axis, climate heterogeneity generated additional opportunities for radiation, but for seasonality it did not. Overall, the physical setting in which a clade diversifies can influence where it falls on the evolutionary continuum, from climate niche conservatism to radiation

Scaling in the Lattice Gas Model

A good quality scaling of the cluster size distributions is obtained for the Lattice Gas Model using the Fisher's ansatz for the scaling function. This scaling identifies a pseudo-critical line in the phase diagram of the model that spans the whole (subcritical to supercritical) density range. The independent cluster hypothesis of the Fisher approach is shown to describe correctly the thermodynamics of the lattice only far away from the critical point.Comment: 4 pages, 3 figure

Ranges of critical temperature and water potential values for the germination of species worldwide: Contribution to a seed trait database

Germination is the first essential stage in crop and food production, as well as for the establishment of trees and regeneration of wild species. Temperature and water potential are the primary environmental factors that control germination in all species, and affect both the rate and final percentage germination. A comprehensive description of intra- and inter-variations between groups of species (perennials and annuals, trees, grasses, crops and wild species) helps understand where these species are currently able to grow on earth and will be in the future. By collecting germination trait data on 243 species from the literature and unpublished data, we provide a wide spectrum of species’ seed germination traits, in the form of a set of parameter values describing germination responses to variations in temperature and water potential. Major differences in germination traits were seen to depend on the climatic conditions where the species grow or originated, with species able to germinate on ice and others unable to germinate below 18 °C. By contrast, within the different plant groups, similar ranges of threshold values were found, linked to the species geo-climatic origin. Crops however germinate faster, their range of threshold temperatures and water potential values is wider, and some crops have higher optimum and maximum temperatures as well as lower water potential threshold values. This is likely the result of human selection for rapid germination and for species able to grow in the wide range of environmental conditions where agriculture was developed. Our analyses revealed correlation between traits: negative correlations appeared between germination speed and temperature thresholds, and between temperature and water potential thresholds. The collected data also form a valuable database, enabling plant establishment to be better taken into account in modeling and simulation studies of vegetation boundaries (wild or cultivated) under changing land-use and climate

Eclipsing Binaries with Possible Light-Time Effect

The period changes of six eclipsing binaries have been studied with focus on the light-time effect. With the least squares method we also calculated parameters of such an effect and properties of the unresolved body in these systems. With these results we discussed the probability of presence of such bodies in the systems with respect to possible confirmation by another method. In two systems we also suggested the hypothesis of fourth body or magnetic activity for explanation of the "second-order variability" after subtraction of the light-time effect of the third body.Comment: 4 pages, 1 figure, 2 tables, conference proceeding

Numerical study on the response of shoreline change to the tidal channel after a beach nourishment project on an embayed beach

Beach erosion is a severe problem worldwide and beach nourishment is widely regarded today as an environmentally acceptable method to protect and enlarge beaches. In many beach nourishment projects on headland-bay beaches, artificial headlands were constructed on the natural headlands to form an embayed beach in static equilibrium to protect the beach more effectively. However, the construction of artificial headland would weaken the water exchange in the bay and make the water quality easy to deteriorate. In a beach nourishment project in Qinhuangdao, China to dispose this discrepancy an engineering measure was conducted: to reserve a tidal channel between the artificial headland and the natural headland to allow the tidal current to pass. In this paper, a shoreline change model was set up based on GENESIS model to evaluate the influence of the reserve of the tidal channel on the shoreline change after the project. The model was verified by reproducing the post-project shoreline. Four different project schemes with different scales of tidal channel were simulated and discussion was given based on the analysis of simulated results. The numerical evaluation of various scheme options indicates that it is feasible to involve the tidal channel in beach nourishment projects with artificial headland and the scale of the tidal channel should be designed based on the hydrodynamic processes and the state of the beach

Quantum Computing via The Bethe Ansatz

We recognize quantum circuit model of computation as factorisable scattering model and propose that a quantum computer is associated with a quantum many-body system solved by the Bethe ansatz. As an typical example to support our perspectives on quantum computation, we study quantum computing in one-dimensional nonrelativistic system with delta-function interaction, where the two-body scattering matrix satisfies the factorisation equation (the quantum Yang--Baxter equation) and acts as a parametric two-body quantum gate. We conclude by comparing quantum computing via the factorisable scattering with topological quantum computing.Comment: 6 pages. Comments welcom