Alcatel-Lucent

About: Alcatel-Lucent is a based out in Stuttgart, Germany. It is known for research contribution in the topics: Signal & Network packet. The organization has 37003 authors who have published 53332 publications receiving 1430547 citations. The organization is also known as: Alcatel-Lucent S.A. & Alcatel.

Nearest Neighbors in Random Subspaces

Abstract: Recent studies have shown that the random subspace method can be used to create multiple independent tree-classifiers that can be combined to improve accuracy. We apply the procedure to k-nearest-neighbor classifiers and show that it can achieve similar results. We examine the effects of several parameters of the method by experiments using data from a digit recognition problem. We show that the combined accuracies follow a trend of increase with increasing number of component classifiers, and that with an appropriate subspace dimensionality, the method can be superior to simple k-nearest-neighbor classification, The method's superiority is maintained when smaller number of training prototypes are available, i.e., when conventional knn classifiers suffer most heavily from the curse of dimensionality.

Metal-insulator transition in disordered two-dimensional electron systems.

Abstract: We present a theory of the metal-insulator transition in a disordered two-dimensional electron gas. A quantum critical point, separating the metallic phase, which is stabilized by electronic interactions, from the insulating phase, where disorder prevails over the electronic interactions, has been identified. The existence of the quantum critical point leads to a divergence in the density of states of the underlying collective modes at the transition, causing the thermodynamic properties to behave critically as the transition is approached. We show that the interplay of electron-electron interactions and disorder can explain the observed transport properties and the anomalous enhancement of the spin susceptibility near the metal-insulator transition.

Ising Pyrochlore Magnets: Low-Temperature Properties, "Ice Rules," and Beyond

Abstract: Pyrochlore magnets are candidates for what Harris et al. [Phys. Rev. Lett. 79, 2554 (1997)] call ``spin-ice'' behavior. We present theoretical simulations of relevance for the pyrochlore family ${R}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ ( $R\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\mathrm{rare}\mathrm{earth}$) supported by magnetothermal measurements on selected systems. By considering long-ranged dipole-dipole as well as short-ranged superexchange interactions, we get three distinct behaviors: (i) an ordered doubly degenerate state, (ii) a highly disordered state with a broad transition to paramagnetism, and (iii) a partially ordered state with a sharp transition to paramagnetism. Closely corresponding behavior is seen in the real compounds.

Effect of antenna polarization on the capacity of a multiple element system in an indoor environment

Abstract: We analyze the behavior of a multiple element antenna system in an indoor environment based on the measurements taken in the Lucent Bell Labs building in Crawford Hill, NJ, with a system of 12 transmitters and 15 receivers. In particular, we investigate the capacity behavior with respect to the polarization of the transmitting/receiving elements and the distance between the transmitting and the receiving arrays. The analysis of the power rolloff versus distance clearly demonstrates the different propagation characteristics of the horizontally versus the vertically polarized electric fields. Under strong line-of-sight (LOS) conditions (hallway environment), the power of the horizontally polarized waves falls off faster with distance than that of the vertically polarized fields. Also, the cross-polarization coupling is about -15 dB. Under nonline-of-sight (NLOS) conditions (labs), both polarizations display similar rolloff behavior with distance and the cross-polarization coupling is about 0 dB. There is a power loss of at least 15 dB under NLOS conditions relative to LOS conditions. The average received signal power affects the system capacity. In the hallway, horizontally polarized systems achieve lower capacities than their vertically polarized counterparts. Also the achievable capacity in the labs is much lower than that in the hallway, because of the lower average received power. The comparison of single polarization systems to hybrid polarization systems shows that combined polarization systems perform better in terms of achievable capacity. Therefore, there lies an advantage in using both electric field polarizations. However, under strong LOS conditions the channel itself inherently limits the capacity behavior of the system.

System and method for routing special number calls in a telecommunication network

Abstract: A system for routing mobile special number calls in a telecommunication network includes: (a) a mobile call originating station for originating a special number call from a call locus; the mobile call originating station includes a position determining unit; (b) a mobile switching station for receiving the special number call; the mobile switching station assigns a temporary identifier for the mobile call originating station at least during the special number call; (c) a mobile geolocation system coupled with the mobile switching station; the mobile geolocation system cooperates with the mobile switching station to query the position determining unit for origination geographic information relating to the call locus; and (d) a special number call service station coupled with the mobile switching station; the special number call being routed to the special number call service station according to at least some of the origination geographic information.