The research is divided into two main parts: the sensing part and the gas delivery part. The reliable chemical information from the chemical sensor requires that the sensitive layer of the sensor exhibits long-term stability. To improve the stability of the sensing layer, camphorsulfonic acid was added to the formic acid. The introduction of photo-irradiation at 254 nm as an additional treatment to the sensing layer was proved to be effective. For gas selectivity of PANI matrix, metal or metal oxide clusters have been incorporated into the matrix. The composite materials of PANI with silver, copper, iron, nickel, palladium and mercury were also prepared and exposed to different gases. The second part of the thesis discusses the gas delivery system to the sensors using the synthetic jet technology. The sniffing functionality was demonstrated using the designed jet cell for operation in the open system. The gas sniffing experiments showed that in the presence of the jet, the response time of the sensor is faster by about two orders of magnitude (20 compared to 1800 seconds). The jet sampling system was applied to continuous monitoring of ammonia gas filter performance using the chemFET array. The jet system collected the gas before and after filtering, and the difference between the two responses was compared to observe the break-through of the filter. It was concluded that the gas sensing system integrated with the gas sampling functionality can be applied to monitor a gas filter performance. The cell was designed so that the impinging jet covers the sensing active area of the array of eight chemFETs. The two-dimensional distribution of the ammonia gas concentrations showed that the jet covers the active sensing area in an effective way so that the sampling volume for sensing is significantly reduced compared with the conventional gas flow cell system. Based on these initial studies shown in this thesis, the proposed gas sniffing system was shown to be effective in realizing fast detections of gases for critical applications of a gas sensor system.

Young children begin to draw spontaneously, and their drawings develop in complexity and skill as they become older. Previously, children's drawings have been utilized to assess aspects of emotional and cognitive development. On the other hand, very few studies have used children's drawings as a tool for understanding their language development. The purpose of this study was to examine the potential for using drawing as an assessment tool for language skill. Therefore, this study explored the relationship between pre-kindergarten children's drawing and language development and stability of this relationship over time. This study also examined whether children's English-language status influenced the drawing-language relationship. The study's subjects were 34 children who attended a pre-kindergarten program in a local elementary school located in a Mid-Western university town. These children participated in take-home reading and drawing activities once a week for one school year. Children's drawings that were completed after reading storybooks with their parents served as data documenting their drawing skills. Classroom teachers' observations of the children's language use were recorded on the Work Sampling System's developmental checklists, and this served as data to document their language skills. A hierarchical regression analysis revealed that children's drawing skill was a significant predictor to their language skill and explained 10% of the variance in language scores. This finding was consistent at both the beginning and end of the school year. Children's English-language status did not make a statistically significant difference in the predictive relationship of drawing for their language skills. Therefore, this study concluded that children's drawings can be used as a supplementary assessment tool to provide information about children's language skills, regardless of their primary language. However, more than half of the language variance was not identified from this study; this is an area for further investigation.

This thesis addresses the problem of detecting changes in the activity of a distant gas source from the response of an array of metal oxide (MOX) gas sensors deployed in an Open Sampling System (OSS). Changes can occur due to gas source activity such as a sudden alteration in concentration or due to exposure to a different compound. Applications such as gas-leak detection in mines or large-scale pollution monitoring can benefit from reliable change detection algorithms, especially where it is impractical to continuously store or transfer sensor readings, or where reliable calibration is difficult to achieve. Here, it is desirable to detect a change point indicating a significant event, e.g. presence of gas or a sudden change in concentration. The main challenges are turbulent dispersion of gas and the slow response and recovery times of MOX sensors. Due to these challenges, the gas sensor response exhibits fluctuations that interfere with the changes of interest. The contributions of this thesis are centred on developing change detection methods using MOX sensor responses. First, we apply the Generalized Likelihood Ratio algorithm (GLR), a commonly used method that does not make any a priori assumption about change events. Next, we propose TREFEX, a novel change point detection algorithm, which models the response of MOX sensors as a piecewise exponential signal and considers the junctions between consecutive exponentials as change points. We also propose the rTREFEX algorithm as an extension of TREFEX. The core idea behind rTREFEX is an attempt to improve the fitted exponentials of TREFEX by minimizing the number of exponentials even further. GLR, TREFEX and rTREFEX are evaluated for various MOX sensors and gas emission profiles. A sensor selection algorithm is then introduced and the change detection algorithms are evaluated with the selected sensor subsets. A comparison between the three proposed algorithms shows clearly superior performance of rTREFEX both in detection performance and in estimating the change time. Further, rTREFEX is evaluated in real-world experiments where data is gathered by a mobile robot. Finally, a gas dispersion simulation was developed which integrates OpenFOAM flow simulation and a filament-based gas propagation model to simulate gas dispersion for compressible flows with a realistic turbulence model.

The goals for most of today’s receiver system are sampling at high-speed, with high resolution and with as few errors as possible. This master thesis describes the design of a high-speed sampling system with"state-of-the-art"components available on the market. The system is designed with a parallel Analog-to-digital converter (ADC) architecture, also called time interleaving. It aims to increase the sampling speed of the system. The system described in this report uses four 12-bits ADCs in parallel. Each ADC can sample at 125 MHz and the total sampling speed will then theoretically become 500 Ms/s. The system has been implemented and manufactured on a printed circuit board (PCB). Up to four boards can be connected in parallel to get 2 Gs/s theoretically. In an approach to increase the systems performance even further, a timing error estimation algorithm will be used on the sampled data. This algorithm estimates the timing errors that occur when sampling with non-uniform time interval between samples. After the estimations, the sampling clocks can be adjusted to correct the errors. This thesis is concerning some ADC theory, system design and PCB implementation. It also describes how to test and measure the system’s performance. No measurement results are presented in this thesis because measurements will be done after this project. The last part of the thesis discusses future improvementsto achieve even higher performance.

<p>The goals for most of today’s receiver system are sampling at high-speed, with high resolution and with as few errors as possible. This master thesis describes the design of a high-speed sampling system with"state-of-the-art"components available on the market. The system is designed with a parallel Analog-to-digital converter (ADC) architecture, also called time interleaving. It aims to increase the sampling speed of the system. The system described in this report uses four 12-bits ADCs in parallel. Each ADC can sample at 125 MHz and the total sampling speed will then theoretically become 500 Ms/s. The system has been implemented and manufactured on a printed circuit board (PCB). Up to four boards can be connected in parallel to get 2 Gs/s theoretically. </p><p>In an approach to increase the systems performance even further, a timing error estimation algorithm will be used on the sampled data. This algorithm estimates the timing errors that occur when sampling with non-uniform time interval between samples. After the estimations, the sampling clocks can be adjusted to correct the errors. </p><p>This thesis is concerning some ADC theory, system design and PCB implementation. It also describes how to test and measure the system’s performance. No measurement results are presented in this thesis because measurements will be done after this project. The last part of the thesis discusses future improvementsto achieve even higher performance.</p>

Les communications futures pour les applications civiles et militaires utilisent des signaux modulés complexes large bande qui seront émis à travers des amplificateurs de puissance multivoie de type DOHERTY qui devront avoir des performances en puissance, rendement, OBO et largeur de bande qui constituent aujourd’hui un véritable défi à relever. Pour ce faire les concepteurs ont besoin d’outils de caractérisation temporelle permettant la mesure normalisées et l’optimisation des tensions et courants aux accès des dispositifs non linéaires sous pointes ou connectorisés. Ce travail de thèse a permis de mettre en œuvre cet outil de caractérisation temporelle qui a été utilisé pour répondre à des besoins spécifiques pour la modélisation de transistor, pour l’optimisation de leur fonctionnement en termes de stabilité impulsion à impulsion, pour la recherche des conditions optimales de leur fonctionnement dans un amplificateur de type Doherty. Pour cette mise en œuvre une modélisation mathématique des échantillonneurs a été réalisée pour évaluer leurs performances et choisir le mieux adapté à la mesure temporelle RF. Des procédures d’étalonnages rigoureuses ont été développées pour obtenir simultanément des formes d’ondes temporelles calibrées à spectre très large (Basse fréquences jusqu’aux Hyperfréquences). / The future communications for civil and military applications will use complex wideband modulated signals to be transmitted through multi-channel DOHERTY power amplifiers which should have high performance in terms of power, efficiency, OBO, and bandwidth. In order to meet these stringent requirements, designers need time-domain characterization tools for calibrated measurements and for optimizing voltages and currents at both ports of non-linear connectorized or on-wafer devices. This work successfully implements time-domain characterization tools used to meet specific needs for transistor modeling, to optimize their operation in terms of pulse to pulse stability, and to search optimal conditions of their operation modes in a Doherty power amplifier. For this implementation, mathematical modeling is performed to evaluate sampler’s performances in terms of time-domain sampling efficiency in order to choose the best suited sampling architecture for RF time-domain measurements. Rigorous calibration procedures have been developed to obtain simultaneously full time-domain calibrated waveforms (from low Frequencies to Microwave frequencies).