ASPECTS REGARDING THE INFLUENCE OF VOLATILITY ON THE OPTION’S PRICE

The most important advantage of the option transactions resides in the fact that it offers, through the existing relations between the derivatives market and the spot market, improved solutions of portfolio management, the put options constituting an insurance policy against the decrease of the prices, and the call options acting as a guarantee for the purchase of the support asset at the pre-set price. The volatility represents a measure of the size of the price fluctuations of the support asset and thus it can be assimilated with a random variable. The analysis of the essential factors that influence the price of the option contracts has demonstrated that the volatility of the support asset's price shows how risky it is for it to be one of the main and most difficult to determine factor, because this is the only parameter that is not known exactly at the moment of the contract conclusion. Under these conditions, due to the profound importance of volatility in the option evaluation and due to the fact that volatility is difficult to estimate, observe or predict, we must model it as a random variable for many of the option contracts for which the model of constant volatility (as the Black Scholes model is) is inadequate..options contract, historical volatility, stochastic volatility, exercise price,standard deviation

THE FINANCIAL MANAGEMENT OF THE SMALL AND MEDIUM SIZED COMPANIES IN ROMANIA

The objective of the paper is to identify the possibilities and promotion limits of the financial management in the small and medium sized companies in Romania starting from the concepts expressed in the literature and expressed in the concrete situations in the Romanian economy practice. We have also presented the role of the financial management in small and medium sized companies and the risk management objective of financial management considering that the risk is a fundamental component of a strategic and tactical decision. At the end of the paper we have presented the conclusions stemming from the study, the basic one being that there is a beginning in the promotion and applicability of theoretical elements of financial management in small and medium sized companies in Romania together with the European integration.small and medium sized companies, financial management, investment, risk, economic profitability

First-principles molecular-dynamics simulations of a hydrous silica melt: Structural properties and hydrogen diffusion mechanism

We use {\it ab initio} molecular dynamics simulations to study a sample of liquid silica containing 3.84 wt.% H$_2$O.We find that, for temperatures of 3000 K and 3500 K,water is almost exclusively dissolved as hydroxyl groups, the silica network is partially broken and static and dynamical properties of the silica network change considerably upon the addition of water.Water molecules or free O-H groups occur only at the highest temperature but are not stable and disintegrate rapidly.Structural properties of this system are compared to those of pure silica and sodium tetrasilicate melts at equivalent temperatures. These comparisons confirm the picture of a partially broken tetrahedral network in the hydrous liquid and suggest that the structure of the matrix is as much changed by the addition of water than it is by the addition of the same amount (in mole %) of sodium oxide. On larger length scales, correlations are qualitatively similar but seem to be more pronounced in the hydrous silica liquid. Finally, we study the diffusion mechanisms of the hydrogen atoms in the melt. It turns out that HOSi$_2$ triclusters and SiO dangling bonds play a decisive role as intermediate states for the hydrogen diffusion.Comment: 25 pages, 18 figures. submitte

Comparative classical and ab initio Molecular Dynamics study of molten and glassy germanium dioxide

A Molecular Dynamics (MD) study of static and dynamic properties of molten and glassy germanium dioxide is presented. The interactions between the atoms are modelled by the classical pair potential proposed by Oeffner and Elliott (OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compare our results to experiments and previous simulations. In addition, an ab initio method, the so-called Car-Parrinello Molecular Dynamics (CPMD), is applied to check the accuracy of the structural properties, as obtained by the classical MD simulations with the OE potential. As in a similar study for SiO2, the structure predicted by CPMD is only slightly softer than that resulting from the classical MD. In contrast to earlier simulations, both the static structure and dynamic properties are in very good agreement with pertinent experimental data. MD simulations with the OE potential are also used to study the relaxation dynamics. As previously found for SiO2, for high temperatures the dynamics of molten GeO2 is compatible with a description in terms of mode coupling theory.Comment: 27 pages, 16 figure

Стабильность эластичных тел с микроструктурой

The aim of this paper is to give sufficient stability conditions for the solutions of linear dynamic theory of elastic media with microstructure. We are dealing here with the stability of the equilibrium solution and the stability of homogeneous mixed initial boundary – value problem.Scopul acestei lucrări este acela de a da condiţii suficiente pentru stabilitatea soluţiilor teoriei dinamicii lineare a mediilor elastice cu microstructură. Ne vom ocupa aici de stabilitatea soluţiei de echilibru şi stabilitatea valorilor la limită în condiţii iniţiale pentru un corp omogen.Le but de cet ouvrage est d’offrir les conditions de stabilité suffisantes pour les solutions de la théorie de la dynamique linéaire de milieux élastiques à microstructure. On parlera de la stabilité de la solution d’équilibre et de la stabilité du problème des valeurs limite d’un corps homogène en conditions initiales.Целью настоящей работы является определение необходимых условий для стабильности решений линейной динамической теории эластичных сред с микроструктурой. Объектом исследований является определение решения равновесия и стабильность граничных значений в начальных условиях для однородного тела

Упругие тела с микроструктурой: проблемы устойчивости

The aim of this paper is to give sufficient stability conditions for the solutions of linear dynamic theory of elastic media with microstructure. We are dealing here with the stability of the equilibrium solution and the stability of homogeneous mixed initial boundary – value problem.Scopul acestei lucrari este acela de a da conditii suficiente pentru stabilitatea solutiilor teoriei dinamicii liniare a mediilor elastice cu microstructura. Ne vom ocupa aici de stabilitatea solutiei de echilibru si stabilitatea valorilor la limita in conditii initiale pentru un corp omogen.Le but de cet ouvrageest d’offrir les conditions de stabilité suffisantes pour les solutions de la théorie de la dynamique linéaire de milieux élastiques à microstructure. On parlera de la stabilité de la solution d’équilibre et de la stabilité du problème des valuers limite d’un corps homogène en conditions initiales.Целью данной работы является чтобы дать достаточые условия для устойчивости решений линейной динамической теории упругих сред с микроструктурой. Будут исследованы вопросы устойсивости решения равновесия и стабильность граничных значений в начальных условиях для однородного тела