Search results for "statistical"

Sensitivity analysis of consumption cycles

2018

We study the special case of a nonlinear stochastic consumption model taking the form of a 2-dimensional, non-invertible map with an additive stochastic component. Applying the concept of the stochastic sensitivity function and the related technique of confidence domains, we establish the conditions under which the system's complex consumption attractor is likely to become observable. It is shown that the level of noise intensities beyond which the complex consumption attractor is likely to be observed depends on the weight given to past consumption in an individual's preference adjustment.

Transitions in consumption behaviors in a peer-driven stochastic consumer network

2019

Abstract We study transition phenomena between attractors occurring in a stochastic network of two consumers. The consumption of each individual is strongly influenced by the past consumption of the other individual, while own consumption experience only plays a marginal role. From a formal point of view we are dealing with a special case of a nonlinear stochastic consumption model taking the form of a 2-dimensional non-invertible map augmented by additive and/or parametric noise. In our investigation of the stochastic transitions we rely on a mixture of analytical and numerical techniques with a central role given to the concept of the stochastic sensitivity function and the related techni…

“The Limits” of Economic Growth in Romania

2014

Abstract A sustainable economic growth of GDP of 3-4% annually in Romania for the reduction of gaps in development was considered impossible by most institutions of various skill and opinion leaders, as well as of international financial bodies. The reasons cited were delayed public reforms, low growth potential as a result of the crisis, the overview status of the states in the Eurozone dependent on inside community trade and also the prospects for a lasting economic stagnation, the balance sheet effect, as a result of over indebtedness of firms and individuals that substantially reduced inclination towards investment and consumption. Contradicting these forecasts, in 2013, Romania's econo…

Production and Foreign Trade of Mineral Products in Latvia and Belarus

2015

Latvia and Belarus are small countries with limited scope of natural resources. However, the available mineral resources play important role in production of mineral products for domestic and foreign consumption. Main goal of the paper is to characterize the role of extraction industry in national economy and mineral products trade in two neighboring countries - Latvia and Belarus. To achieve the goal, the role of mining and quarrying industry in Latvia and Belarus was identified; trade of mineral resources in Latvia was analyzed. The main trends in the development of its own mineral resources of the Republic of Belarus were identified, the role of mineral resources in the commodity structu…

Entropy measures in Image Classification

2005

Large scale semi-supervised image segmentation with active queries

2011

A semiautomatic procedure to generate classification maps of remote sensing images is proposed. Starting from a hierarchical unsupervised classification, the algorithm exploits the few available labeled pixels to assign each cluster to the most probable class. For a given amount of labeled pixels, the algorithm returns a classified segmentation map, along with confidence levels of class membership for each pixel. Active learning methods are used to select the most informative samples to increase confidence in the class membership. Experiments on a AVIRIS hyperspectral image confirm the effectiveness of the method, especially when used with active learning query functions and spatial regular…

A Support Vector Domain Description Approach to Supervised Classification of Remote Sensing Images

2007

This paper addresses the problem of supervised classification of remote sensing images in the presence of incomplete (nonexhaustive) training sets. The problem is analyzed according to two different perspectives: 1) description and recognition of a specific land-cover class by using single-class classifiers and 2) solution of multiclass problems with single-class classification techniques. In this framework, we analyze different one-class classifiers and introduce in the remote sensing community the support vector domain description method (SVDD). The SVDD is a kernel-based method that exhibits intrinsic regularization ability and robustness versus low numbers of high-dimensional samples. T…

Automatic regrouping of strata in the goodness-of-fit chi-square test

2019

Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …

Finding condensed descriptions for multi-dimensional data.

1976

Abstract We describe two programs that may be used to find condensed descriptions for data available in a contingency table or in a covariance matrix in the case that these data follow a multinomial or a multivariate normal distribution, respectively. The programs perform a stepwise model search among multiplicative models by computing appropriate likelihood-ratio test statistics.

Uncertainty quantification analysis of the biological Gompertz model subject to random fluctuations in all its parameters

2020

[EN] In spite of its simple formulation via a nonlinear differential equation, the Gompertz model has been widely applied to describe the dynamics of biological and biophysical parts of complex systems (growth of living organisms, number of bacteria, volume of infected cells, etc.). Its parameters or coefficients and the initial condition represent biological quantities (usually, rates and number of individual/particles, respectively) whose nature is random rather than deterministic. In this paper, we present a complete uncertainty quantification analysis of the randomized Gomperz model via the computation of an explicit expression to the first probability density function of its solution s…