Evelyn Arencibia García

Advanced Multisensorial Barrier for Obstacle Detection

In the current railway systems, it is becoming more necessary to have safety elements in order to avoid accidents. One of the causes that can provoke serious accidents is the existence of obstacles in railways, either fixed or mobiles. In this work, a multisensorial system is proposed in order to inform the monitoring system of the existence of obstacle. The use of different sensors for the same task is justified by the high degree of reliability needed in these environments, where the safety is fundamental.

Hardware optimization of Generalized Pairwise Complementary sequences generation

Generalized Pairwise Complementary (GPC) sequences are increasingly being used in many applications due to their properties, which allow uncorrelated sequences generation from a base pair. The generation of these sequences is conducted by iterative algorithms developed to be implemented in hardware platforms. However, in order to reduce even further the amount of resources required for the implementation, these algorithms can be improved with digital synthesis as the final goal. This work proposes an improved GPC sequences generator developed for FPGA platforms, which notoriously reduces resources requirements by applying some concepts developed for Golay sequences generation. FPGA implementation is performed with generic parameters to evaluate and compare it with the straightforward approach.

Genetic algorithm for searching a Doppler resilient multilevel complementary waveform

This work proposes the use of Genetic Algorithms (GAs) to search a Doppler resilient multilevel complementary pair of sequences. The fitness function deals with the desired ambiguity function to be fit, while it minimizes the crest factor of the resulting sequences. The simulated results show how the waveform obtained has a better performance than that achieved with binary sequences.

Aqueous-liquids characterization based on encoded ultrasonic signals

This paper presents a system modelling for aqueous-liquids characterization by ultrasounds. The main goal of the proposed model is the use of different kind of signals, based on encoding along a large bandwidth in order to obtain information about the liquid mixtures to be characterized. The validation of the model has been carried out by comparing it with experimental results. Besides, the experimental setup used has been also validated by comparing the propagation velocity of several samples with some references in literature. Therefore, the proposed model constitutes a suitable alternative to characterize aqueous-liquids by ultrasounds. Liquid characterization; encoded transmissions; ultrasonic signal procesing;

Hardware implementation of an efficient correlator for Golay pairs derived from kernels of lengths 2, 10 and 26

Golay complementary pairs have been widely used in signal coding and pulse compression systems due to the ideal sum of their aperiodic correlation functions. Furthermore, they can be used as basic building blocks for the generation of novel encoding schemes with zero correlation zones. In a recent work, algorithms for the efficient generation and correlation of Golay pairs obtained from kernels 2, 10 and 26 have been proposed. These pairs can adapt better the processing gain to the application requirements than previous ones based on power-of-two pairs. This work presents a new hardware implementation in configurable logic of an efficient correlator of Golay complementary pairs build from kernels 2, 10 and 26. This implementation allows real-time operation in cases in which high frequencies or long sequences are involved and can be easily adapted to the requirements of the application thanks to a set of generic parameters. This fast correlator, together with Golay code possibilities, make them a good choice for applications based on CDMA techniques, such as sonar, or wireless communications.

Estimating bearing angles by encoding ultrasonic transmissions at different frequencies

One of the main drawbacks of ultrasonic transducers is the difficulty to determine the bearing angle of echoes coming from an obstacle placed in front. Echoes often provide only the distance to the reflector inside the emission cone of the transducer, so some applications associate several transducers with the same scanning area to obtain more information about the common reflectors. This work proposes the use of encoded transmissions along a large bandwidth in order to estimate the bearing angle of echoes with only one transducer, even in cases with low signal-to-noise ratios.

Implementation of a transmission encoding system for a track circuit

The current development of railway transport gives a significant importance to the design of suitable and reliable safety systems. Among them, the common track circuit can be improved to enhance its performance, by providing redundancy, immunity to noise and more information from the track circuit. This work proposes a novel track circuit based on the encoding of the electrical transmissions with Kasami codes. Every node emits its corresponding code that can be detected at next nodes by correlation techniques. The suitable selection of orthogonal sequences, as well as different carrier frequencies for emissions, allow to have simultaneous emissions and receptions without cross interferences.

Efficient management of an advanced data acquisition system with real time streaming

In this work the specific software tools designed to manage a high performance data acquisition board to be used in active multi-sensory systems is presented. Specifically, the developments which has been carried out allow to monitor the coded emission/reception of two sensory barriers for obstacle detection on railways, based on infrared (IR) and ultrasonic (US) sensors. Additionally, it has been developed the tools to detect the coded emissions. As a result of that, it can be detected the existence of obstacles between both barriers, based on the lack of signal at the receiving barrier. The developed software can be considered the previous step to implement the hardware prototype. Initially it has been validated the feasibility of the algorithm, optimizing the processing time to obtain the detection results in quasi-real time.