Philips

About: Philips is a company organization based out in Vantaa, Finland. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 68260 authors who have published 99663 publications receiving 1882329 citations. The organization is also known as: Koninklijke Philips Electronics N.V. & Royal Philips Electronics.

Reversible electrowetting and trapping of charge : model and experiments

Abstract: We derive a model for voltage-induced wetting, so-called electrowetting, from the principle of virtual displacement. Our model includes the possibility that charge is trapped in or on the wetted su...

First-principles calculation of the magnetocrystalline anisotropy energy of iron, cobalt, and nickel

Abstract: The magnetocrystalline anisotropy energies of the elements iron, cobalt, and nickel have been calculated by means of the linear muffin-tin orbital (LMTO) method in the atomic-sphere approximation (ASA) within the framework of the local-spin-density approximation (LSDA). The so-called ``force theorem'' is used to express the total-energy difference, when spin-orbit coupling is included, as a difference in sums of Kohn-Sham single-particle eigenvalues. The results depend strongly on the location and dispersion of degenerate energy bands near the Fermi surface, and particular attention must be paid to the convergence of the Brillouin-zone integral of the single-particle eigenvalues. The calculated values of the anisotropy energy are too small by comparison with experiment, and we do not predict the correct easy axis for cobalt and nickel. We find that the variation of the anisotropy energy with changes in strain, in the magnitude of the spin-orbit coupling, for different choices of the exchange-correlation potential and for varying numbers of valence electrons are not capable of explaining these incorrect results. By comparing our calculated energy bands with those obtained by a full-potential linear augmented plane wave (FLAPW) method we conclude that the discrepancy is not attributable to terms in the potential that are neglected in the ASA.

A discrete dynamic contour model

Abstract: A discrete dynamic model for defining contours in 2-D images is developed. The structure of this model is a set of connected vertices. With a minimum of interaction, an initial contour model can be defined, which is then automatically modified by an energy minimizing process. The internal energy of the model depends on local contour curvature, while the external energy is derived from image features. Solutions are presented to avoid undesirable deformation effects, like shrinking and vertex clustering, which are common in existing active contour models. The deformation process stops when a local minimum of the energy function is reached. The final shape of the model is a reproducible approximation of the desired contour. Results of applying the method to computer-generated images, as well as clinical images, are presented. >

Microscopic understanding of the anisotropic conductivity of PEDOT:PSS thin films

Abstract: The anisotropic conductivity of spin-coated poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films by temperature-dependent conductivity measurements, has been analyzed. A detailed 3D morphological model was derived from topographic scanning tunneling microscopy (STM) and cross-sectional atomic force microscopy (AFM) images, which correlated the anisotropy, both in conductivity magnitude and in the conduction mechanism. Spin coated films of PEDOT:PSS formed a reasonably homogenous material in terms of electrical conductivity. It was observed that the vertical conductivity that is perpendicular to the substrate, can be up to three orders of magnitude lower than the lateral conductivity in the plane of the film. The macroscopic in-plane conductivity was found to be completely isotropic, and the ordering was found to be confined to randomly oriented micrometer-size domains.

Dynamic Frame Length ALOHA

Abstract: Adding frame structure to slotted ALOHA makes it very convenient to control the ALOHA channel and eliminate instability. The frame length is adjusted dynamically according to the number of garbled, successful, and empty timeslots in the past. Each terminal that has a packet to transmit selects at random one of the n timeslots of a frame. Dynamic frame length ALOHA achieves a throughput (expected number of successful packets per timeslot) of 0.426 which compares favorably with the 1/e (\approx0.368) upper bound of ordinary slotted ALOHA.