Factor intensity and order of resource extraction

This paper characterizes the optimal time paths of extraction of several nonrenewable resource deposits with different costs of extraction when the extracted resource can be converted into productive capital and the extraction process, as well as the production of the substitute, requires two primary factors of production. Under a technological assumption granting that the time paths of primary factor prices are monotonic, we show that, for each pair (lower cost/higher cost) of deposits, an intensity condition is necessary in order to have discontinuous extraction of the lower cost deposit. We also show that the same condition is sufficient for discontinuous extraction of the lower cost deposit, provided the stock of the lower cost deposit is sufficiently large and the stocks of all other deposits are sufficiently small.Exhaustible resources; Optimal control; Order of extraction

Neural Network Characterization of Reflectarray Antennas

An efficient artificial neural network (ANN) approach for the modeling of reflectarray elementary components is introduced to improve the numerical efficiency of the different phases of the antenna design and optimization procedure, without loss in accuracy. The comparison between the results of the analysis of the entire reflectarray designed using the simplified ANN model or adopting a full-wave characterization of the unit cell finally proves the effectiveness of the proposed model

A note on intrinsic Conditional Autoregressive models for disconnected graphs

In this note we discuss (Gaussian) intrinsic conditional autoregressive (CAR) models for disconnected graphs, with the aim of providing practical guidelines for how these models should be defined, scaled and implemented. We show how these suggestions can be implemented in two examples on disease mapping.Comment: 14 page

An equivalence relation in finite planar spaces

AbstractThis paper is concerned with quasiparallelism relation in a finite planar space S. In particular, we prove that if no plane in S is the union of two lines quasiparallelism relation between planes is an equivalence relation. Moreover, three-dimensional affine spaces with a point at infinity and three-dimensional affine spaces with a line at infinity are characterized

On Vector Spaces with Formal Infinite Sums

We discuss possible definitions of categories of vector spaces enriched with a notion of formal infinite linear combination in the likes of the formal infinite linear combinations one has in the context of generalized power series, we call these \textit{categories of reasonable strong vector spaces} (r.s.v.s.). We show that, in a precise sense, the more general possible definition for a strong vector space is that of a small $\mathrm{Vect}$-enriched endofunctor of $\mathrm{Vect}$ that is right orthogonal, for every cardinal $\lambda$, to the cokernel of the canonical inclusion of the $\lambda$-th copower in the $\lambda$-th power of the identity functor: these form the objects for a universal r.s.v.s. we call $\Sigma\mathrm{Vect}$. We relate this category to what could be understood to be the obvious category of strong vector spaces $B\Sigma\mathrm{Vect}$ and to the r.s.v.s. $K\mathrm{TVect}_s$ of separated linearly topologized spaces that are generated by linearly compact spaces. We study the number of iterations of the obvious approximate reflector on $\mathrm{Ind}\text{-}(\mathrm{Vect}^{\mathrm{op}})$ needed to construct the orthogonal reflector $\mathrm{Ind}\text{-}(\mathrm{Vect}^{\mathrm{op}}) \to \Sigma\mathrm{Vect}$ as it relates to the problem of constructing the smallest subspace of an $X \in \Sigma\mathrm{Vect}$ closed under taking infinite linear combinations containing a given linear subspace of $H$ of $X$. Finally we show the natural monoidal closed structure on $\mathrm{Ind}\text{-}(\mathrm{Vect}^{\mathrm{op}})$ restricts naturally to $\Sigma\mathrm{Vect}$ and apply this to define an infinite-sum-sensitive notion of K\"ahler differentials for generalized power series. Most of the technical results apply to a more general class of orthogonal subcategories of $\mathrm{Ind}\text{-}(\mathrm{Vect}^{\mathrm{op}})$ and we work with that generality

Varying coefficient models as Mixed Models : reparametrization methods and bayesian estimation

Non-linear relationships are accommodated in a regression model using smoothing functions. Interaction may occurs between continuous variable, in this case interaction between nonlinear and linear covariate leads to varying coefficent model (VCM), a subclass of generalized additive model. Additive models can be estimated as generalized linear mixed models, after being reparametrized. In this article we show three different type of matrix design for mixed model for VCM, by applying b-spline smoothing functions. An application on real data is provided and model estimates re computed with a Bayesian approach

The effect of sunlight on decoration placement and mating success in male satin bowerbirds

Males of some bird species choose sunlit display sites to enhance their visual signal. Satin bowerbird (Ptilonorhynchus violaceus) males place colored decorations on their bower platform as part of their courtship display. Little is known about how illumination affects the attractiveness of decorations. We analyzed photographs to quantify the amount of direct illumination on the bower and the number of blue decorations in sunlight. We found that the proportion of sunlight on the entire bower platform during peak female visitation periods is correlated with male mating success. The North platform, where decorations are concentrated, was proportionately more illuminated than the South platform. Males placed decorations in more sunlit areas on the platform and returned moved blue decorations to their original locations, suggesting that males actively place blue decorations in sunlit areas. This is the first study to demonstrate that greater illumination in off-body displays may be important for attracting females

Entire-domain basis function MoM formulation for a substrate backed periodically loaded array of narrow strips

J.R. Wait's entire-domain basis function method of moments matrix formulation for modeling scattering from periodically loaded wires in free space is modified using the current edge approximation and extended to include a multilayer substrate. From this matrix formulation, novel analytical formulations for the current and the effective transfer impedance are obtained. The convergence of the matrix and analytical formulations is improved with the aid of an expression by A.L VanKoughnett. Furthermore, for the case of an electrically dense array, the analytical expression of the effective transfer impedance leads to a simple impedance model which is more general than previously published expressions

Bayesian approach for uncertainty quantification in water quality modelling: The influence of prior distribution

Mathematical models are of common use in urban drainage, and they are increasingly being applied to support decisions about design and alternative management strategies. In this context, uncertainty analysis is of undoubted necessity in urban drainage modelling. However, despite the crucial role played by uncertainty quantification, several methodological aspects need to be clarified and deserve further investigation, especially in water quality modelling. One of them is related to the “a priori” hypotheses involved in the uncertainty analysis. Such hypotheses are usually condensed in “a priori” distributions assessing the most likely values for model parameters. This paper explores Bayesian uncertainty estimation methods investigating the influence of the choice of these prior distributions. The research aims at gaining insights in the selection of the prior distribution and the effect the user-defined choice has on the reliability of the uncertainty analysis results. To accomplish this, an urban stormwater quality model developed in previous studies has been employed. The model has been applied to the Fossolo catchment (Italy), for which both quantity and quality data were available. The results show that a uniform distribution should be applied whenever no information is available for specific parameters describing the case study. The use of weak information (mostly coming from literature or other model applications) should be avoided because it can lead to wrong estimations of uncertainty in modelling results. Model parameter related hypotheses would be better dropped in these cases