XXXIII Simpósio Brasileiro de Telecomunicações

This paper shows that the quality of coded images based on Vector Quantization and Discrete Cosine Transform could be enhaced by using the weighted LBG Algorithm where the weights are calculated using μ Law. Simulation results show improvements up to 0.62 dB.

This paper presents a Traffic Engineering technique applied to Green Networks which concerns on the optimization formulation, rather than on heuristic methods, as usually observed in the literature, and is focused on the backbone of an IP network, presenting an approach to select routers and circuits to be switched off during periods of low...

This paper evaluates the relevance of using a fi- nite state Markov channel, more specifically the Gilbert-El liot channel (GEC) in order to reproduce the behavior of a discret e communications system, based on the IEEE 802.11 standard, with OFDM modulation and frequency-selective fading. Symb ol errors generated by the transmission of codewords...

This paper presents the design of a dual - band microstrip antenna with dual polarization characteristic for high altitude platforms (HAPs ). The antenna has two isolated ports and is suitable for terminals with receiving and transmitting functions operating simultaneously. The element is designed for operation at 5.8 and 7 GHz with 100 MHz...

This paper proposes a method for the identification of TPs sharing the same binder, based on the analysis of phantom circuit measurements. Herein, phantoming is used to reveal if a 4-wire loop composed by two TPs are close enough in order to be considered in the same binder. K-means and Gaussian Mixture Model are evaluated on S11 parameter...

In this paper, assuming an interference-limited eavesdropper scenario, the secrecy outage performance of multiple-input multiple-output wiretap channels with transmit antenna selection is investigated. Considering that the transmitter (Tx) and the receiver (Rx) are equipped with NA and NB antennas, respectively, while the passive eavesdropper is set with...

This paper presents the evaluation of the fading results on mobile propagation channel at distinct phytophysionomic and geomorphological sorts of cerrado biome. The tested frequencies were 144 and 435 MHz. The programming tasks were developed on Matlab language, release 2008. The methodology applied allowed to set up an appropriate margin level...

The missing data approach was developed to perform automatic speech recognition in noisy environments. This technique identifies and uses in the recognition process only parts of a noisy utterance which were not heavily corrupted by the noise, these parts are called reliable. There are two main methods that can be used to achieve this goal: the...

This paper presents an implementation of the Spatio- Temporal Compositions (STC) method for the detection of video anomalies. The STC, as the Bag of Video words (BOV), uses a dictionary to eliminate to redundancies, but differs from it by taking into consideration the spatio-temporal composition of small volumes of videos. The STC also performs a...

This work introduces the warped discrete-time S- transform and the warped discrete S-transform to improve th e time frequency representation of the well-known S-transfo rm. The proposed transforms make use of a non-uniform mapping of tones in the frequency domain to increase the time frequen cy resolution in a specified frequency band. Numerical...