0 Se p 20 02 The Dynamical Parameters of the Universe
The results of different analyses of the dynamical parameters of the Universe are converging towards agreement. Remaining disagreements reflect systematic errors coming either from the observations or from differences in the methods of analysis. Compiling the most precise parameter values with our estimates of such systematic errors added, we find the following best values: the baryonic density parameter Ω b h 2 = 0.019 ± 0.02, the density parameter of the matter component Ω m = 0.29 ± 0.06, the density parameter of the cosmological constant Ω λ = 0.71 ± 0.07, the spectral index of scalar fluctuations n s = 1.02 ± 0.08, the equation of state of the cosmological constant w λ < −0.86, and the deceleration parameter q 0 = −0.56 ± 0.04. We do not modify the published best values of the Hubble parameter H 0 = 0.73 ± 0.07 and the total density parameter Ω 0 +0.03 −0.02 .
A Cosmological Model
(I) IT is familiar that the Einstein equations for the density and pressure in a uniform universe: do not suffice to specify the model since there are two equations and three unknown functions, ρ, p and R. A very common assumption is p = 0, but models involving both positive and negative values of p have also been proposed. McCrea1 pointed out that there is no objection in principle to negative pressure and that the steady-state universe can be interpreted in this way.
DEM generation from new VIR sensors: IKONOS, ASTER and Landsat-7
DEM generation is a living R&D topic since new-launched satellite images can be used to generate stereoscopic images. Using a coplanarity equation model developed at CCRS and an automatic matching method developed at PCI, DEMs are generated with new VIR stereo data. Accuracy of 4.9 m with high-resolution IKONOS images, and 33 m and 101 m with medium-resolution ASTER and Landsat-7 ETM/sup +/ images respectively are obtained. The same matching accuracy of one-pixel is translated into worse results with Landsat due to a small B/H ratio of 0.15.