436 research outputs found
Using DEA to evaluate efficiency of higher education
The aim of the higher education reform process both in Hungary and in the European countries is establishing a competitive,
qualitative higher education with efficiently operating institutions. The question of efficiency needs increased attention not only because of
the decline of the state support but also the rapid raise of the student mass.
In the education system it’s not easy to measure the output of the services. The situation is more complicated if an organisation or a sector has
multiple inputs and outputs. In this case a possible method of determining efficiency is Data Envelopment Analysis. In my paper I’d like to introduce
this method and use it to compare the efficiency of higher education systems. Furthermore I am examining whether their efficiency is influenced by
the extent of the contribution of the state and the private sector or socio-economic factors like GDP per capita and education level of parents
CORPORATE VALUATION USING TWO-DIMENSIONAL MONTE CARLO SIMULATION
In this paper, we have presented a corporate valuation model. The model combine several valuation methods in order to get more accurate results. To determine the corporate asset value we have used the Gordon-like two-stage asset valuation model based on the calculation of the free cash flow to the firm. We have used the free cash flow to the firm to determine the corporate market value, which was calculated with use of the Black-Scholes option pricing model in frame of the two-dimensional Monte Carlo simulation method. The combined model and the use of the two-dimensional simulation model provides a better opportunity for the corporate value estimation.corporate valuation, free cash flow to the firm, real options, Black-Scholes option pricing model, two-dimensional Monte Carlo simulation, R statistics
Pre-maximum spectroscopic diversity of hydrogen-poor superluminous supernovae
We search for the reasons behind the spectroscopic diversity of hydrogen-poor
superluminous supernovae (SLSNe-I) in the pre-maximum phase. Our analysis is a
continuation of the paper of \citet{ktr21}, who disclosed two new subtypes of
SLSNe-I characterized by the presence/absence of a W-shaped absorption feature
in their pre-maximum spectra between 4000 and 5000 \AA (called Type~W and
Type~15bn, respectively). However, the physical cause of this bimodality is
still uncertain. Here we present pre-maximum spectral synthesis of 27 SLSNe-I
with special attention to the photospheric temperature () and
velocity () evolution. We find that a limit of
12000~K separates the Type~W and Type~15bn SLSNe-I: Type~W objects tend to show
12000~K, while Type~15bn ones have 12000~K. This is consistent with the chemical composition of the studied
objects. Another difference between these groups may be found in their ejecta
geometry: Type W SLSNe-I may show null-polarization, implying spherical
symmetry, while the polarization of Type 15bn objects may increase in time.
This suggests a two-component model with a spherical outer carbon-oxygen layer
and an asymmetric inner layer containing heavier ions.
The two subgroups may have different light curve evolution as well, since 6
Type~W objects show early bumps, unlike Type 15bn SLSNe-I.
This feature, however, needs further study, as it is based on only a few
objects at present.Comment: 23 pages, 37 figure
Towards green rating systems in Hungarian road design
Abstract
To measure the environmental impacts, life cycle assessment techniques appeared. The paper presents the SimaPro, which is one of the most widely, used software for life cycle assessment. Studies indicate that environmental impact can be considerably reduced in the planning and the design stages, if sustainability is evaluated. Therefore, a system of objective measurement is inevitable. Nowadays, numerous road rating systems exist and are used around the World. Taking into consideration EU directives, employing a rating system in Hungary has great importance. Therefore, paper presents an action plan to develop a domestic sustainable evaluation tool for road construction
The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel
The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment
Photospheric Velocity Gradients and Ejecta Masses of Hydrogen-poor Superluminous Supernovae -- Proxies for Distinguishing between Fast and Slow Events
We present a study of 28 Type I superluminous supernovae (SLSNe) in the
context of the ejecta mass and photospheric velocity. We combine photometry and
spectroscopy to infer ejecta masses via the formalism of radiation diffusion
equations. We show an improved method to determine the photospheric velocity by
combining spectrum modeling and cross correlation techniques. We find that Type
I SLSNe can be divided into two groups by their pre-maximum spectra. Members of
the first group have the W-shaped absorption trough in their pre-maximum
spectrum, usually identified as due to O II. This feature is absent in the
spectra of supernovae in the second group, whose spectra are similar to
SN~2015bn. We confirm that the pre- or near-maximum photospheric velocities
correlate with the velocity gradients: faster evolving SLSNe have larger
photosheric velocities around maximum. We classify the studied SLSNe into the
Fast or the Slow evolving group by their estimated photosheric velocities, and
find that all those objects that resemble to SN~2015bn belong to the Slow
evolving class, while SLSNe showing the W-like absorption are represented in
both Fast and Slow evolving groups. We estimate the ejecta masses of all
objects in our sample, and obtain values in the range of 2.9 (0.8) - 208
(61) , with a mean of . We conclude that
Slow evolving SLSNe tend to have higher ejecta masses compared to the Fast
ones. Our ejecta mass calculations suggests that SLSNe are caused by energetic
explosions of very massive stars, irrespectively of the powering mechanism of
the light curve.Comment: 21 pages, Submitted to Ap
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