Tesis doctoral de Alexander Vergara Tinoco
One of the major problems in gas sensing systems that use metal oxide devices is the lack of reproducibility, stability and selectivity. In order to tackle these troubles experienced with metal oxide gas sensors, different strategies have been developed in parallel. Some of these are related to the improvement of materials, or the use of sample conditioning and pre-treating methods. Other widely used techniques include taking benefit of the unavoidable partially overlapping sensitivities by using sensor arrays and pattern recognition techniques or the use of dynamic features from the gas sensor response. in the last years, modulating the working temperature of metal oxide gas sensors has been one of the most used methods to enhance sensor selectivity. this occurs because, since, the sensor response is different at different working temperatures, and therefore, measuring the sensor response at n different temperatures is, in some cases, similar to the use of an array comprising n different sensors. This allows for measuring multivariate information from every single sensor and helps in keeping low the dimensionality of the measurement system needed to solve a specific application. Although the good results reported, until now, the selection of the frequencies used to modulate the working temperature remained an empirical process and that is not an accurate method to ensure that the best results are reached for a given application. in view of this context, the principal objective of this doctoral thesis was to develop a systematic method to determine which are the optimal temperature modulation frequencies to solve a given gas analysis problem. This method, which is borrowed from the field of system identification, has been developed and introduced for the first time in the area of gas sensors. It consists of studying the sensor response to gases when the operating temperature is modulated via maximum-length pseudo-random sequences. Suc
Datos académicos de la tesis doctoral «Improving the performance of micro-machined metal oxide gas sensors: optimization of the temperature modulation mode via pseudo-random sequences«
- Título de la tesis: Improving the performance of micro-machined metal oxide gas sensors: optimization of the temperature modulation mode via pseudo-random sequences
- Autor: Alexander Vergara Tinoco
- Universidad: Rovira i virgili
- Fecha de lectura de la tesis: 25/07/2006
Dirección y tribunal
- Director de la tesis
- Eduard Llobet Valero
- Tribunal
- Presidente del tribunal: xavier Correig blanchar
- Luis Fonseca (vocal)
- corrado Di natale (vocal)
- angel Rodríquez (vocal)