Morphological filtering on hypergraphs

The focus of this article is to develop computationally efficient mathematical morphology operators on hypergraphs. To this aim we consider lattice structures on hypergraphs on which we build morphological operators. We develop a pair of dual adjunctions between the vertex set and the hyper edge set of a hypergraph H, by defining a vertex-hyperedge correspondence. This allows us to recover the classical notion of a dilation/erosion of a subset of vertices and to extend it to subhypergraphs of H. Afterward, we propose several new openings, closings, granulometries and alternate sequential filters acting (i) on the subsets of the vertex and hyperedge set of H and (ii) on the subhypergraphs of a hypergraph

Adaptive ‘imperfect’ decision feedback equalizer for a frequency selective communication channel

In this paper, we show that, for an uncoded receiver system, the proposed least mean square (LMS) decision aided equalizer (DAE), with, the backward step-size constant greater than forward step-size constant, compared to classical equal-step size design, has a lower mean square error by upto 5 dB, for a frequency selective wireless communication channel. Classical LMS DAE with equal step-size constants, can be considered as perfect decision feedback system, compared to, the proposed unequal step-size, as a imperfect decision feedback system. We provide, Wiener DAE, considering imperfect decision feedback information, during training mode and provide analysis for LMS DAE with unequal step size constants

First results from the CAWSES-India Tidal Campaign

The first CAWSES-India Tidal Campaign was conducted by the Indian scientific community during March–April 2006. The objectives of this campaign were: (1) To determine the characteristics of tides in the troposphere and lower stratosphere (0–20 km) and mesosphere and lower thermosphere (MLT) region (80–100 km), (2) to explore and identify what lower atmospheric processes drive middle atmospheric tides in the Indian continental region and (3) to provide information on those short-term variabilities of MLT tides that are likely to have an impact on the ionospheric variabilities and contribute to the upper atmospheric weather. Data sets from experiments conducted at the three low latitude radar sites, namely, Trivandrum (8.5° N, 76.9° E), Tirunelveli (8.7° N, 77.8° E) and Gadanki (13.5° N, 79.2° E) and fortnightly rocket launches from Thumba were made use of in this study. An important observational finding reported in this work is that the radar observations at Tirunelveli/Trivandrum indicate the presence of 15–20 day modulation of diurnal tide activity at MLT heights during the February–March period. A similar variation in the OLR fields in the western Pacific (120–160° longitude region) suggests a possible link between the observed tidal variabilities and the variations in the deep tropical convection through the nonmigrating tides it generates

Gravity waves observed from the Equatorial Wave Studies (EWS) campaign during 1999 and 2000 and their role in the generation of stratospheric semiannual oscillations

International audienceThe altitude profiles of temperature fluctuations in the stratosphere and mesosphere observed with the Rayleigh Lidar at Gadanki (13.5° N, 79.2° E) on 30 nights during January to March 1999 and 21 nights during February to April 2000 were analysed to bring out the temporal and vertical propagation characteristics of gravity wave perturbations. The gravity wave perturbations showed periodicities in the 0.5?3-h range and attained large amplitudes (4?5 K) in the mesosphere. The phase propagation characteristics of gravity waves with different periods showed upward wave propagation with a vertical wavelength of 5?7 km. The mean flow acceleration computed from the divergence of momentum flux of gravity waves is compared with that calculated from monthly values of zonal wind obtained from RH-200 rockets flights. Thus, the contribution of gravity waves towards the generation of Stratospheric Semi Annual Oscillation (SSAO) is estimated

The common and uncommon cestodal infestation encountered in routine histopathological practice from a semi-urban population in south India and their public health importance.

Parasites are encountered uncommonly in routine histopathologic practice. Among them, cestodes form a major bulk. Cysticercosis heads the list forming the bulk of cases followed by Hydatidosis and Sparganosis. Microscopic identification of inflammation with surrounding reactions along with other morphological features forms the mainstay of diagnosis of parasitic diseases on histopathology. Identification of the parasites on histopathological examination would reduce the cost-diagnosis ratio avoiding expensive serological investigation

Sensitivity Analysis for Shortest Path Problems and Maximum Capacity Path Problems in Undirected Graphs

This paper addresses sensitivity analysis questions concerning the shortest path problem and the maximum capacity path problem in an undirected network. For both problems, we determine the maximum and minimum weights that each edge can have so that a given path remains optimal. For both problems, we show how to determine these maximum and minimum values for all edges in O(m + K log K) time, where m is the number of edges in the network, and K is the number of edges on the given optimal path