Incomplete pairwise comparison and consistency optimization

This paper proposes a new method for calculating the missing elements of an incomplete matrix of pairwise comparison values for a decision problem. The matrix is completed by minimizing a measure of global inconsistency, thus obtaining a matrix which is optimal from the point of view of consistency with respect to the available judgements. The optimal values are obtained by solving a linear system and unicity of the solution is proved under general assumptions. Some other methods proposed in the literature are discussed and a numerical example is presented.     

Conditions for characterizing the structure of optimal strategies in infinite-horizon dynamic programs

The study of infinite-horizon nonstationary dynamic programs using the operator approach is continued. The point of view here differs slightly from that taken by others, in that Denardo's local income function is not used as a starting point. Infinite-horizon values are defined as limits of finite-horizon values, as the horizons get long. Two important conditions of an earlier paper are weakened, yet the optimality equations, the optimality criterion, and the existence of optimal structured strategies are still obtained.     

Nonparametric time series prediction: A semi-functional partial linear modeling

There is a recent interest in developing new statistical methods to predict time series by taking into account a continuous set of past values as predictors. In this functional time series prediction approach, we propose a functional version of the partial linear model that allows both to consider additional covariates and to use a continuous path in the past to predict future values of the process. The aim of this paper is to present this model, to construct some estimates and to look at their properties both from a theoretical point of view by means of asymptotic results and from a practical perspective by treating some real data sets. Although the literature on the use of parametric or nonparametric functional modeling is growing, as far as we know, this is the first paper on semiparametric functional modeling for the prediction of time series.     

Noninvertible maps and their embedding into higher dimensional invertible maps

The first part is devoted to a presentation of specific features of noninvertible maps with respect to the invertible ones. When embedded into a three-dimensional invertible map, the specific dynamical features of a plane noninvertible map are the germ of the three-dimensional dynamics, at least for sufficiently small absolute values of the embedding parameter. The form of the paper, as well as its contents, is approached from a non abstract point of view, in an elementary form from a simple class of examples.     

Fuzzy Galois Connections

The concept of Galois connection between power sets is generalized from the point of view of fuzzy logic. Studied is the case where the structure of truth values forms a complete residuated lattice. It is proved that fuzzy Galois connections are in one-to-one correspondence with binary fuzzy relations. A representation of fuzzy Galois connections by (classical) Galois connections is provided.     

A short note on convergence near a high order zero

The behaviour of different iteration schemes, when used to find a high order zero, is studied from the point of view of function value reduction. It is found that the ratio between successive function values, for a given scheme, converges to a value for increasing order of the zero.     

A classification of the main probability distributions by minimizing the weighted logarithmic measure of deviation

The paper reanalyzes the following nonlinear program: Find the most similar probability distribution to a given reference measure subject to constraints expressed by mean values by minimizing the weighted logarithmic deviation. The main probability distributions are examined from this point of view and the results are summarized in a table.The author acknowledges the NSERC Canada Research Grant A-5712.     

Computational properties of three-term recurrence relations for Kummer functions

Several three-term recurrence relations for confluent hypergeometric functions are analyzed from a numerical point of view. Minimal and dominant solutions for complex values of the variable z are given, derived from asymptotic estimates of the Whittaker functions with large parameters. The Laguerre polynomials and the regular Coulomb wave functions are studied as particular cases, with numerical examples of their computation.     

A class of estimators with estimated optimum values in sample surveys

Srivastava and Jhajj (1981) proposed a class of estimators for population mean of a character using auxiliary information and optimum values involving unknown parameters. From the practical point of view, their results have very little utility. In view of practical utility, we propose a class of estimators with estimated optimum values. Further, it is shown that the proposed class with estimated optimum values attains the same minimum mean square error of the class of estimators based on optimum values.     

A study on the bilinear Caudrey-Dodd-Gibbon equation

In this paper we consider the Hirota transformation of the Caudrey-Dodd-Gibbon equation (CDGE) from another point of view. As a result, the local equivalence between the CDGE and its bilinear equation is established, and a new type of Bäcklund transformation, which is defined by a second-order ODE along with the appropriate initial values, is presented to construct new solutions for the bilinear CDGE from the seed solutions of original CDGE.     

中国股票市场的收益-风险关系和惯性分析

本文采用非对称 EGARCH-M模型刻画了中国股票市场的个股风险 ,并对全市场的收益 -风险特征进行了横向分析 ,结果表明 ,从长期的角度来讲 ,在正常的市场条件下 ,中国股票市场存在着一定的高风险 -高收益、低风险 -低收益的关系 ,但从短期来看 ,由于不确定性因素较多 ,这种风险收益关系并不显著 .其次 ,本文分别采用每只股票历史 3个月的累积收益率、6个月的累积收益率以及 1 2个月的累积收益率分析了中国股票市场的惯性 ,我们发现 ,无论是从短期还是从比较长的时间来看 ,中国股票市场都不存在市场惯性 ,而表现出一定的反转现象 ,但反转现象会随着时间的推移逐渐减弱     

Egalitarianism meets ideologies of mathematical education–instances from Norwegian curricula and classrooms

The article starts focusing egalitarianism in a Norwegian curricular context in general and in mathematics education from primary schools to teacher education in particular. It progresses by locating and problematizing some major ideologies in mathematics education such as rationalism, activism, competitivism and ‘autodidactism’ on one hand and egalitarianism on the other. Some results from TIMSS, where Norway differs significantly from other countries, are touched upon and contrasted with episodes from qualitative studies. It is asked, from a general didaktic point of view, whether egalitarian values in mathematics education should be seen as strength or weekness, and the other way round, whether mathematical education contributes to or counterworks egalitarianism in society.     

Waves in fluid-filled elastic tubes with a stenosis: Variable coefficients KdV equations

In the present work, by treating the arteries as thin-walled prestressed elastic tubes with a stenosis and the blood as an inviscid fluid we have studied the propagation of weakly nonlinear waves in such a medium, in the longwave approximation, by employing the reductive perturbation method. The variable coefficients KdV and modified KdV equations are obtained depending on the balance between the nonlinearity and the dispersion. By seeking a localized progressive wave type of solution to these evolution equations, we observed that the wave speeds takes their maximum values at the center of stenosis and gets smaller and smaller as one goes away from the stenosis. Such a result seems to reasonable from the physical point of view.     

Comparison between Eulerian and Lagrangian semi-analytical models to simulate the pollutant dispersion in the PBL

In this work we display a numerical comparison, under statistical and computational point of view, between semi-analytical Eulerian and Lagrangian dispersion models to simulate the ground-level concentration values of a passive pollutant released from a low height source. The Eulerian approach is based on the solution of the advection–diffusion equation by the Laplace transform technique. The Lagrangian approach is based on solution of the Langevin equation through the Picard’s Iterative Method. Turbulence inputs are calculated according to a parameterization capable of generating continuous values in all stability conditions and in all heights of the Planetary Boundary Layer (PBL). Numerical simulations and comparisons show a good agreement between predicted and observed concentrations values. The comparison reveals the main advantages and disadvantages between the models.     

A Study of Global Optimization Using Particle Swarms

A number of recently proposed variants of the particle swarm optimization algorithm (PSOA) are applied to an extended Dixon-Szeg und constrained test set in global optimization. Of the variants considered, it is shown that constriction as proposed by Clerc, and dynamic inertia and maximum velocity reduction as proposed by Fourie and Groenwold, represent the main contenders from a cost efficiency point of view. A parameter sensitivity analysis is then performed for these two variants in the interests of finding a reliable general purpose off-the-shelf PSOA for global optimization. In doing so, it is shown that inclusion of dynamic inertia renders the PSOA relatively insensitive to the values of the cognitive and social scaling factors.     

A two-species competitive system under the influence of toxic substances

The effect of toxicants on ecological systems is an important issue from mathematical and experimental points of view. In this paper, we have studied the dynamical behaviours of a two-species competitive system affected by toxic substances. Boundedness, local and global stabilities are addressed. We have also studied the stability of this system with diffusion around the non-trivial stable (in the deterministic case) equilibrium point in a random environment. Extensive numerical simulations are performed using analytical results for a hypothetical set of parameter values.     

Smoothing by L-spline functions of many variables

We investigate the problem of the smoothing of experimental data by cell-like L-spline functions of many variables from the point of view of the theory of such functions proposed by the author. Given values of a function and its derivatives up to some order are smoothed on a rectangular network of nodes. Existence and uniqueness of the solution are proved and equations are derived.     

Conditionally Optimal Weights of Evidence

A weight of evidence is a calibrated statistic whose values in [0,1] indicate the degree of agreement between the data and either of two hypothesis, one being treated as the null (H_0) and the other as the alternative (H_1). A value of zero means perfect agreement with the null, whereas a value of one means perfect agreement with the alternative. The optimality we consider is minimal mean squared error (MSE) under the alternative while keeping the MSE under the null below a fixed bound. This paper studies such statistics from a conditional point of view, in particular for location and scale models.     

Statistics and game theory: Estimating coalitional values in R software

In this paper we illustrate the usage of R software in cooperative game theory. In particular, we address the problems that arise in exactly calculating the coalitional values for general TU-games in which a large amount of players is involved. In these settings, their approximation may be useful in practice. We analyse these sampling methods from a statistical point of view, from a theoretical and an empirical approach.     

Optimal strategies for the uninformed player

This paper provides a counterpart of the well-known recursive formula for finitely repeated zero-sum games with lack of information on one side from the point of view of the uninformed player. Applying the results to a specific game that has already been discussed by Mertens and Zamir, for the first time a nontrivial sequence of values and optimal strategies is explicitly computed. This allows to recover their startling result on the appearance of the normal law in such models by entirely different arguments.