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A computational system based on mobile devices that allows to create delinquency indicators in a cartographic map is proposed. With this system, the end user will be capable of identifying, assimilating and avoiding delinquency, as well as collaborating with its reduction and eradication. The work is motivated by the notorious increment of the insecurity perception of the citizens of Mexico City, as stated on the Mexico peace index report of 2017. As a result of the study, models of maps with geo-referenced incidents are provided. Also, it makes use of geo-location and mobile positioning, with the objective of contributing to the surveillance of delinquency, detecting earlier the undesirable events and serve as basis for decision making in terms of security. [ABSTRACT FROM AUTHOR]

A description and comparison of three visual extended cryptography algorithms is presented. Currently these methods are often used as a basis for developing more complex schemes. Results related to overlapping shades, pixel expansion, quality of images and shades, and the number of coded images are obtained. In conventional visual cryptography a secret image is encrypted into a set of images that look like random-noise and are distributed to each participant of the scheme. To obtain the secret image the images received must be super-imposed. .In the extended visual cryptography the shades are visually recognizable images. It is concluded that the three methods present particular advantages depending on the application. [ABSTRACT FROM AUTHOR]

In this paper, a review for threshold-based visual cryptography (VC), a visual representation of the secret sharing scheme is presented. The VC has potential applications in the electronic banking system, as well as in personal identification systems. En la VC a binary image such as letters, logotypes or halftone images are shared among a group of participants using a set of images, so called shares. Until now several VC schemes, such as threshold-based VC, the general access VC and the extended VC, have been proposed. The conditions that must be satisfied for a correct recovery of the secret message, as well as the most relevant security issues of this scheme are also analyzed. [ABSTRACT FROM AUTHOR]

A video watermarking algorithm, in which watermark embedding and detection process are carried out during the MPEG-2 coding process is proposed. The watermark signal is embedded in the DCT coefficients of blue channel of I-frames and P-frames. The embedding energy is computed adaptively using perceptual information of the I-frames and the P-frames, and motion vectors information in the P-frame. Computer simulation results show the watermark imperceptibility, obtaining a PSNR greater than 45 dB and maintaining its robustness to common signal distortions such as contamination by noise, cropping, frame dropping, frame swapping and frame averaging, among others. The proposed algorithm has very little influence on the MPEG decoding speed. [ABSTRACT FROM AUTHOR]

In this paper, it is proposed to apply the discrete cosine transform (DCT) and the compressive sampling (CS) techniques to audio signal compression. Using spectral analysis and the properties of the DCT, audio signals can be treated as sparse signals in the frequency domain. This is especially true for sounds representing tones. Thus, it is proposed using the DCT as a preprocessor to obtain a sparse representation in the frequency domain, combined with CS to obtain an efficient representation of the signals. It is shown that the subsequent application of CS represents the signals with less information than the well-known sampling theorem. [ABSTRACT FROM AUTHOR]

To increase the efficiency of the independent component analysis (ICA) and reduce the computational complexity of the system, this paper proposes a methodology based on the compressive sampling with minimum measurements. This allows compressing and modifying the Gaussian characteristics of audio signals. ICA is one of the most widely used schemes for separating the sources involved in an audio mixture received in a set of sensors. However, for proper operation it is required that the signals involved in the mixture do not have Gaussian characteristics or at most only one of them be Gaussian, characteristics that are not satisfied by the audio signals, which have in general Gaussian characteristics. The proposed methodology allows obtaining a better separation with lower computational complexity, and with a more efficient separation of the mixed signals, even if the signals involved in the mixture are of Gaussian toe. [ABSTRACT FROM AUTHOR]