3,309 research outputs found
Gravitational Waves in the Nonsymmetric Gravitational Theory
We prove that the flux of gravitational radiation from an isolated source in
the Nonsymmetric Gravitational Theory is identical to that found in Einstein's
General Theory of Relativity.Comment: 10 Page
Arithmetic coding revisited
Over the last decade, arithmetic coding has emerged as an important compression tool. It is now the method of choice for adaptive coding on multisymbol alphabets because of its speed,
low storage requirements, and effectiveness of compression. This article describes a new implementation of arithmetic coding that incorporates several improvements over a widely used earlier version by Witten, Neal, and Cleary, which has become a de facto standard. These improvements include fewer multiplicative operations, greatly extended range of alphabet sizes and symbol probabilities, and the use of low-precision arithmetic, permitting implementation by fast shift/add operations. We also describe a modular structure that separates the coding, modeling, and probability estimation components of a compression system. To motivate the improved coder, we consider the needs of a word-based text compression program. We report a range of experimental results using this and other models. Complete source code is available
The Resolvent Average for Positive Semidefinite Matrices
We define a new average - termed the resolvent average - for positive
semidefinite matrices. For positive definite matrices, the resolvent average
enjoys self-duality and it interpolates between the harmonic and the arithmetic
averages, which it approaches when taking appropriate limits. We compare the
resolvent average to the geometric mean. Some applications to matrix functions
are also given
Thermodynamic ground states of platinum metal nitrides
The thermodynamic stabilities of various phases of the nitrides of the
platinum metal elements are systematically studied using density functional
theory. It is shown that for the nitrides of Rh, Pd, Ir and Pt two new crystal
structures, in which the metal ions occupy simple tetragonal lattice sites,
have lower formation enthalpies at ambient conditions than any previously
proposed structures. The region of stability with respect to those structures
extends to 17 GPa for PtN2. Calculations show that the PtN2 simple tetragonal
structures at this pressure are thermodynamically stable also with respect to
phase separation. The fact that the local density and generalized gradient
approximations predict different values of the absolute formation enthalpies as
well different relative stabilities between simple tetragonal and the pyrite or
marcasite structures are further discussed.Comment: 5 pages, 4 figure
Experimental hydrodynamics of the accelerated turbulent boundary layer with and without mass injection
Hydrodynamics of accelerated turbulent boundary layer with and without mass injectio
The turbulent boundary layer on a porous plate - Experimental heat transfer with uniform blowing and suction, with moderately strong acceleration
Heat transfer to transpired turbulent boundary layer on porous plate with moderately strong acceleratio
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