Compressed representation of a partially defined integer function over multiple arguments

In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

Determinants of small and medium sized fast growing enterprises in central and eastern Europe: a panel data analysis

The purpose of this paper is to explore the main determinants of growth in small and medium sized enterprises (SMEs) in central and eastern Europe. The important role played by SMEs in the economic development of central and eastern European (CEE) countries has attracted the recent attention of academics and policymakers but remains relatively unexplored. Empirical research has suggested that firm growth is determined not only by the traditional characteristics of size and age but also by other firm-specific factors such as indebtedness, internal financing, future growth opportunities, process and product innovation, and organisational changes. Although growth in manufacturing and service SMEs in transition economies is well explained by the traditional firm characteristics of size and age, there is no empirical evidence concerning what other specific factors may be associated with SME growth and performance in these countries. Using a panel dataset of 560 fast growing small and medium enterprises from six transition economies we find that firm size when measured by firm total assets can explain to a large extent the growth in SMEs in these countries. When size is proxied by a firm’s number of employees the observed effect is marginal. Firm specific characteristics such as leverage, current liquidity, future growth opportunities, internally generated funds, and factor productivity are found to be important factors in determining a firm’s growth and performance. Age and ownership do not seem to be able to explain firm growth. The results of our empirical study have also some policy implications: we argue that governments in transition economies need to pay an increased attention to small and medium sized enterprises and try to create a business environment that will be beneficial for SME development.transition economy, small and medium enterprise, growth, panel data analysis

Assessment of Information Asymmetry

2000 Mathematics Subject Classification: 62P20, 91B42In the process of trading, the seller and buyer participate with different initial knowledge about the technical capabilities and about the expected use of the good. This two-side asymmetry affects the success of the negotiation in e -trading. This paper discusses one practical approach to assess information asymmetry and the role of warranty in seller-buyer communication relationship. The presented approach is illustrated with a survey experiment.Partialy supported by Pro-ENBIS GTC1 -2001-4303

Classification of Texts' Authorship Using a Regression Model on Compressed Data

2010 Mathematics Subject Classification: 68T50,62H30,62J05.An algorithm for text authorship identification is proposed. The procedure is based on the Kolmogorov complexity and uses regression models on the length of the compressed texts. The classification employs the regression parameters estimates. Different combinations of compressor parameters and the preliminary processing on the data are examined using prose texts of a few English classics

Novel superconducting phases of Tl-based compounds

Researchers report the measurements of the I(sub c)(T) of the 102 K phase. They also discuss briefly the composition of the lattice parameters and the ac susceptibility relation to the grain size and microstructure

Solar activity influence on cosmic ray penetration in the middle atmosphere

A new improved model for cosmic rays-middle atmosphere interaction is developed. The ionization q(h)-profile dependence on penetrating high energy particles composition (protons, alpha-particles and heavier nuclei) and energy spectra (solar activity modulation included) are investigated. A computer program, realizing the Gaussian algorithm for solving of multidimensional integrals is created. The corresponding electron density profiles N(h) at solar minimum and maximum are obtained

Towards a Maximal Mass Model

We investigate the possibility to construct a generalization of the Standard Model, which we call the Maximal Mass Model because it contains a limiting mass $M$ for its fundamental constituents. The parameter $M$ is considered as a new universal physical constant of Nature and therefore is called the fundamental mass. It is introduced in a purely geometrical way, like the velocity of light as a maximal velocity in the special relativity. If one chooses the Euclidean formulation of quantum field theory, the adequate realization of the limiting mass hypothesis is reduced to the choice of the de Sitter geometry as the geometry of the 4-momentum space. All fields, defined in de Sitter p-space in configurational space obey five dimensional Klein-Gordon type equation with fundamental mass $M$ as a mass parameter. The role of dynamical field variables is played by the Cauchy initial conditions given at $x_5 = 0$, guarantying the locality and gauge invariance principles. The corresponding to the geometrical requirements formulation of the theory of scalar, vector and spinor fields is considered in some detail. On a simple example it is demonstrated that the spontaneously symmetry breaking mechanism leads to renormalization of the fundamental mass $M$. A new geometrical concept of the chirality of the fermion fields is introduced. It would be responsible for new measurable effects at high energies $E \geq M$. Interaction terms of a new type, due to the existence of the Higgs boson are revealed. The most intriguing prediction of the new approach is the possible existence of exotic fermions with no analogues in the SM, which may be candidate for dark matter constituents.Comment: 28 page

Intensive MHD-structures penetration in the middle atmosphere initiated in the ionospheric cusp under quiet geomagnetic conditions

In connection with the recently detected quasiperiodical magnetic disturbances in the ionospheric cusp, the penetration of compressional surface magnetohydrodynamic (MHD) waves through the middle atmosphere is modelled numerically. For the COSPAR International Reference Atmosphere (CIRA) 72 model the respective energy density flux of the disturbances in the middle atmosphere is determined. On the basis of the developed model certain conclusions are reached about the height distribution of the structures (energy losses, currents, etc.) initiated by intensive magnetic cusp disturbances

An Application of ISO 5725 in Brewing Industry

2002 Mathematics Subject Classification: 62P30, 62P10.The colloidal stability is very important part of the total beer quality. The stabilized beers have to have a long shelf-life. Determination of some haze forming complexes could be very useful for prediction of beer colloidal stability. We study the repeatability and reproducibility of a method for determination of some haze forming complexes in beer. The method was tested in 10 laboratories. All of theme analyzed the same beer samples and carried out two measurements for each. Statistical evaluation of results was according ISO 5725 and previous experience. The applied ISO 5725 statistical analyzes ensured high quality and possibility of international recognition of the measurement method.Partially supported by Mathind IST-2000-26015 and by Pro-enbis GTC1-2001-43031

Intertwined Hamiltonians in Two Dimensional Curved Spaces

The problem of intertwined Hamiltonians in two dimensional curved spaces is investigated. Explicit results are obtained for Euclidean plane,Minkowski plane, Poincar{\' e} half plane ($AdS_2$), de Sitter Plane ($dS_2$), sphere, and torus. It is shown that the intertwining operator is related to the Killing vector fields and the isometry group of corresponding space. It is shown that the intertwined potentials are closely connected to the integral curves of the Killing vector fields. Two problems of considered as applications of the formalism presented in the paper. The first one is the problem of Hamiltonians with equispaced energy levels and the second one is the problem of Hamiltonians whose spectrum are like the spectrum of a free particle.Comment: To appear in Annals of Physic