Regular orbit closures in module varieties

Let A be a finitely generated associative algebra over an algebraically closed field. We characterize the finite dimensional modules over A whose orbit closures are regular varieties.Comment: 11 page

The role of courts in the War on Terror

The normative position of the judiciary under the traditional conception of democracy as self-legislation by the people is too weak to protect in an effective way the rights of suspects in the global War on Terror. Drawing on arguments elaborated by Hans Kelsen and Karl Popper, we shall attempt to devise in this paper an alternative democracy conception that could serve as a much more solid foundation for the judicial branch of government in a democratic state. Through this jurisprudential strategy, we hope to be able to maintain the balance of normative power among the Trias Politica, which, in turn, may contribute to the preservation of the legal rights of every person during the struggle against terrorists

Bounds on the volume fraction of 2-phase, 2-dimensional elastic bodies and on (stress, strain) pairs in composites

Bounds are obtained on the volume fraction in a two-dimensional body containing two elastically isotropic materials with known bulk and shear moduli. These bounds use information about the average stress and strain fields, energy, determinant of the stress, and determinant of the displacement gradient, which can be determined from measurements of the traction and displacement at the boundary. The bounds are sharp if in each phase certain displacement field components are constant. The inequalities we obtain also directly give bounds on the possible (average stress, average strain) pairs in a two-phase, two-dimensional, periodic or statistically homogeneous compositeComment: 16 pages, 2 figures, Submitted to Comptes Rendus Mecaniqu

Reconstruction and stability in acousto-optic imaging for absorption maps with bounded variation

The aim of this paper is to propose for the first time a reconstruction scheme and a stability result for recovering from acoustic-optic data absorption distributions with bounded variation. The paper extends earlier results on smooth absorption distributions. It opens a door for a mathematical and numerical framework for imaging, from internal data, parameter distributions with high contrast in biological tissues

Dynamic modelling and estimation of the error due to asynchronism in a redundant asynchronous multiprocessor system

The use of Redundant Asynchronous Multiprocessor System to achieve ultrareliable Fault Tolerant Control Systems shows great promise. The development has been hampered by the inability to determine whether differences in the outputs of redundant CPU's are due to failures or to accrued error built up by slight differences in CPU clock intervals. This study derives an analytical dynamic model of the difference between redundant CPU's due to differences in their clock intervals and uses this model with on-line parameter identification to idenitify the differences in the clock intervals. The ability of this methodology to accurately track errors due to asynchronisity generate an error signal with the effect of asynchronisity removed and this signal may be used to detect and isolate actual system failures