12,661 research outputs found
Noise figure considerations in the design of superhetrodyne receiver input circuits.
Thesis (M.A.)--Boston Universit
Current and planned use of the Navstar Global Positioning System by NASA
NASA was quick to realize the potential that the Global Positioning System (GPS) had to offer for its many diverse vehicles, experiments and platforms. Soon after the first Block 1 GPS satellites were launched, NASA began to use the tremendous capabilities that they had to offer. Even with a partial GPS constellation in place, important results have been obtained about the shape, orientation and rotation of the earth and calibration of the ionosphere and troposphere. These calibrations enhance geophysical science and facilitate the navigation of interplanetary spacecraft. Some very important results have been obtained in the continuing NASA program for aircraft terminal area operations. Currently, a large amount of activity is being concentrated on real time kinematic carrier phase tracking which has the potential to revolutionize aircraft navigation. This year marks the launch of the first GPS receiver equipped earth-orbiting NASA spacecraft: the Extreme Ultraviolet Explorer and the Ocean Topography Experiment (TOPEX/Poseidon). This paper describes a cross section of GPS-based research at NASA
Postindustrialism and postmaterialism? A critical view of the new economy, the information age, the high tech society and all that
The theory of postindustrial society and postmaterialist culture can explain neither the structural uniformities of modern society captured by convergence theory nor the national differences captured by theories of democratic corporatism and the mass society. Its depiction of structural changes is superficial: the service sector is too heterogeneous to describe occupational and industrial trends; the idea of technocratic dominance is overblown and misses big national differences in the location and role of experts and intellectuals. As for postindustrial values, they apply to a small population, a minority even of college students. That these attitudes fluctuate so much with shifting economic conditions and political agendas casts doubt on the idea of a basic shift toward postmaterial values. The literature documenting such shifts is plagued with problems of survey validity. It goes up against a heavy weight of evidence showing that older issues of security, equality, civic order and crime, economic growth and stability are dominant in the politics and mentality of modern populations; that cohort effects are weak to non-existent; that political generational effects are rare and soon fade away; that family life cycle, if carefully delineated, has an impact across a wide range of attitudes and behavior. Most important, differences in national mobilizing structures shape both mass and elite responses to the dilemmas and problems of modern life. Assessing related images of modern society - the information age, the high-tech society - the paper finds these equally misleading. This paper is based on chs. 1 and 4 of H.L. Wilensky, Rich Democracies: Political Economy, Public Policy, and Performance (University of California Press, 2002). --
The macroeconomic effects of world trade in financial assets
This article analyzes some of the potential effects of increased international financial integration within a simple two-country model. In the model, the article considers a switch in the menu of internationally traded financial securities from bonds to complete contingent claims and examines the impact of this switch on the stochastic properties, including the cross-country correlations, of standard macroeconomic aggregates like output, consumption, and labor effort, as well as the trade balance.International finance
Quantum Anti-de Sitter space and sphere at roots of unity
An algebra of functions on q-deformed Anti-de Sitter space AdS_q^D is defined
which is covariant under U_q(so(2,D-1)), for q a root of unity. The
star-structure is studied in detail. The scalar fields have an intrinsic
high-energy cutoff, and arise most naturally as fields on orbifolds AdS_q^D
\times S^D/G if D is odd, and AdS_q^D \times S_{\chi}^{2D-1}/G if D is even.
Here G is a finite abelian group, and S_{\chi} is a certain ``chiral sector''
of the classical sphere. Hilbert spaces of square integrable functions are
discussed. Analogous results are found for the q-deformed sphere S_q^D.Comment: 45 pages, LaTeX, 2 figures using epsf. Slight change in notation
allows to obtain AdS^2, AdS^3 as special cases of the general schem
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