We consider the problem of finding a transitive orientation of a comparability graph, such that the edge set of its covering graph contains a given subset of edges. We propose a solution which employs the classical technique of modular tree decomposition. The method leads to a polynomial time algorithm to construct such an orientation or report that it does not exist. © 2006 Elsevier B.V. All r...

We propose a new gradient-based method for the extraction of the orientation field associated to a fingerprint, and a regularisation procedure to improve the orientation field computed from noisy fingerprint images. The regularisation algorithm is based on three new integral operators, introduced and discussed in this paper. A pre-processing technique is also proposed to achieve better performa...

anodic aluminum oxide (aao) fabricated by two step anodization technique, is used as a template to synthesize feco nanowire arrays by ac electrodeposition technique. response surface methodology (rsm) is applied to design the experiments, fit an empirical model and optimize the conditions to achieve the best magnetic properties. the magnetic properties, pore dimensions, composition and structur...

We elucidate the crystalline nature and the three-dimensional orientation of isolated organic nanocrystals embedded in a sol-gel matrix, using a polarized nonlinear microscopy technique that combines two-photon fluorescence and second harmonic generation. This technique allows the distinction between monocrystalline structures and nanoscale polycrystalline aggregates responsible for incoherent ...