VII International Telecommunications Symposium

Classification of voice aging has many applications in health care and geriatrics. This work focuses on finding the most relevant parameters to classify voice aging. The most significant parameters extracted from the glottal signal are chosen to identify the voice aging process of men and women. After analyzing their statistics, the chosen parameters...

In this paper we present a new privacy scheme against passive adversaries based on the message modulation instead of classical cryptographic models for low cost wireless devices, such as an RFID tag. The idea is to become the adversary in disadvantage related to the reader-tag communication channel, for example, by reducing her signal-to-noise ratio.

Implementation of logical gates by pulse modulation in nonlinear fiber directional coupler is investigated numerically. We consider pulses from an optical time-division multiplex system operating with pulse-position modulation (PPM). Such a system is simulated by a PPM modulator. The study shows that with a proper phase control it is possible...

ext Generation etworks ( xG ), as pursued by international standards development organizations, represent the telecommunication operator approach to provide convergent multimedia experience for their users with improved support for mobility and unfettered service access. In contrast, research efforts in so-called ew Generation etworks...

Adobe Portable Document Format is de facto standard today due to its widespread use. One of the features of Adobe pdf is that it allows exporting documents as images that may be saved in JPEG, PNG, and TIFF formats. This paper uses an OCR platform to quantitatively assess the quality of these image file formats.

A large amount of studies deals with the base station placement problem (BSP), but few studies involve the selection of base stations to meet a set of users. This paper presents an approach for solving BSP problems in an indoor environment, aiming at meeting a set of users, with a minimum number of base stations, using a binary particle...

It is well known that one of the main implementation issues in multicarrier modulation schemes, like OFDM, is their high peak-to-average power ratio (PAPR). Power amplifiers that are employed in the transmitters of communications systems are highly non-linear devices, which present a saturation level, and typically show a higher power efficiency...

The problem of locating facial landmarks is important in many applications such as security, 3D modeling and expression recognition. In this paper, we present a new facial landmarks detection system. The core of the proposed system is a cascade of a new detector based on correlation filters. This detector inherits from the correlation filters the...

The use of array beamforming in modern wireless communication systems has been increasingly investigated, due to their potential in rejecting interference and improving the system capacity. The so-called blind algorithms have been considered in such application in order to avoid training procedures and improve the overall transmission...

This paper evaluates the performance of quaternary LDPC codes associated to OFDM systems. The LDPC codes are based on a ring Z4 of integers modulo-4. Each OFDM subcarrier is modulated using a 4-PSK modulation, and each output symbol of the encoder is mapped onto that modulation. The performance is evaluated, in terms of BER versus Eb/N0, for AWGN...