Bidirectional Associative Memories (BAM) are systems that allow to associate pairs of patterns. Once a memory has learned, patterns can be recalled in two directions. BAMs have many applications in pattern recognition and image processing. The aim of this survey is to present several models of BAM throughout time, since Kosko [1988] proposed the first model; followed by those works based on or inspired by it, trying to improve recall capacity; to some recent one-shot models—such as Morphological BAM and Alpha-Beta BAM—which are of particular interest, given their superior performance.

Abstract:This work proposes the use of the Hermite Transform (HT) for imprinting audio files with hidden information. One of the most important aspects of this kind of concealment derives from the amount of data that a host file (audio, images, data, or video) can hold. In this particular case, both the host and the hidden files are audio files. The amount of information that can be hiddenwith the suggested technique-occupies half the length of the host file. Furthermore, the use of the Hermite Transform on audio files helps improve the algorithm performance. Experimental results show that our proposal is efficient and effective, because the audio file concealment is imperceptible to human hearing. Performance of our proposal was assessed using correlation and peak signal to noise ratio. The results strengthen the effectiveness of the method.

Slot antennas are widely used devices in microwave communications, especially when they are used as arrays, one of its applications are as WiFi antennas. We present the analysis of a slot antenna using the Finite Difference Time Domain Method (FDTD). The FDTD method is an easy way to analyze complex structures; the theoretical analysis of a slot antenna supposes the slots are impressed over an infinite plane, missing the effect of the scattered fields in the waveguide sides, as the FDTD simulates the electromagnetic field, considering the media characteristics point by point, is possible to see its behavior in a more exactly way. The application example is a 9 element resonant array designed using the Chebyshev technique to reduce side lobes, antenna behavior was analyzed and then constructed; the results show a good agreement between both, simulation and experiment.

This paper shows the procedure to obtain a continuous coverage map based on a collection of power meas- urements using a Geographic Information System, through satellite photographs of the Professional Unit Adolfo Lopez Mateos, and a group of punctual samples of the power of the Common Pilot Channel (CPICH); which is used to estimate the radio communications channel conditions, taken at different positions and dis- tances. These samples were taken using specialized equipment to obtain georeferenced measurements, and by a technique of statistical prediction, as the Krige Method, generate continuous coverage maps, making it possible to know the distribution of power, and therefore understanding the behavior and configuration of a Base Station, which in third generation cellular systems is also called Node B