830 research outputs found
Optimisation and Just-in-Time
Arranging production activities to fit in with other construction activities is one of the basic ideas of the Just-in-Time approach. In the construction industry it has never been very fully applied. This is a mistake [1]. Construction works, particularly expensive parts of them, are a field where the approach can be and should be applied
Management Processes in Technical-economic Design, Decision-making, Fractals and Market Bubbles
Not include
Dynamic Simulations in Cost and Time Estimation of the Construction Process
This paper describes a model which is able to simulate the costs and the duration of construction for a building project. The model predicts the set of expected costs and the duration of the project depending on input parameters such as production rate, scope of the work, the time schedule, bonding conditions, maximum and minimum deviations from the scope of the work, and the production rate. Clients are able to make proper decisions concerning the time and cost schedules of their investments.
Significance of SMEs in the Czech Economy and Supporting SMEs as an Instrument of the Regional Development
SMEs (Small and Medium Enterprises) are important segments of the economic landscape of the Czech Republic, since half of economic production is attributable to SMEs (52.85 %). The role of SMEs in the Czech Republic is the outcome of a long history of economic development and industrialization throughout the 20th century. Large enterprises prefer to locate their factories according to range of regional opportunities. Small enterprises are more dependent on business conditions in their region. The transaction costs are relatively high for small firms. These contraints mean that regions without an attractive environment for business need to create acceptable conditions for small businesses, if they are looking for sustainable development
Effective Dielectric Tensor for Electromagnetic Wave Propagation in Random Media
We derive exact strong-contrast expansions for the effective dielectric
tensor \epeff of electromagnetic waves propagating in a two-phase composite
random medium with isotropic components explicitly in terms of certain
integrals over the -point correlation functions of the medium. Our focus is
the long-wavelength regime, i.e., when the wavelength is much larger than the
scale of inhomogeneities in the medium. Lower-order truncations of these
expansions lead to approximations for the effective dielectric constant that
depend upon whether the medium is below or above the percolation threshold. In
particular, we apply two- and three-point approximations for \epeff to a
variety of different three-dimensional model microstructures, including
dispersions of hard spheres, hard oriented spheroids and fully penetrable
spheres as well as Debye random media, the random checkerboard, and
power-law-correlated materials. We demonstrate the importance of employing
-point correlation functions of order higher than two for high
dielectric-phase-contrast ratio. We show that disorder in the microstructure
results in an imaginary component of the effective dielectric tensor that is
directly related to the {\it coarseness} of the composite, i.e., local
volume-fraction fluctuations for infinitely large windows. The source of this
imaginary component is the attenuation of the coherent homogenized wave due to
scattering. We also remark on whether there is such attenuation in the case of
a two-phase medium with a quasiperiodic structure.Comment: 40 pages, 13 figure
Long-range memory model of trading activity and volatility
Earlier we proposed the stochastic point process model, which reproduces a
variety of self-affine time series exhibiting power spectral density S(f)
scaling as power of the frequency f and derived a stochastic differential
equation with the same long range memory properties. Here we present a
stochastic differential equation as a dynamical model of the observed memory in
the financial time series. The continuous stochastic process reproduces the
statistical properties of the trading activity and serves as a background model
for the modeling waiting time, return and volatility. Empirically observed
statistical properties: exponents of the power-law probability distributions
and power spectral density of the long-range memory financial variables are
reproduced with the same values of few model parameters.Comment: 12 pages, 5 figure
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