Time-domain optimization of amplifiers based on distributed genetic algorithms

Thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Electrical and Computer EngineeringThe work presented in this thesis addresses the task of circuit optimization, helping the designer facing the high performance and high efficiency circuits demands of the market and technology evolution. A novel framework is introduced, based on time-domain analysis, genetic algorithm optimization, and distributed processing. The time-domain optimization methodology is based on the step response of the amplifier. The main advantage of this new time-domain methodology is that, when a given settling-error is reached within the desired settling-time, it is automatically guaranteed that the amplifier has enough open-loop gain, AOL, output-swing (OS), slew-rate (SR), closed loop bandwidth and closed loop stability. Thus, this simplification of the circuit‟s evaluation helps the optimization process to converge faster. The method used to calculate the step response expression of the circuit is based on the inverse Laplace transform applied to the transfer function, symbolically, multiplied by 1/s (which represents the unity input step). Furthermore, may be applied to transfer functions of circuits with unlimited number of zeros/poles, without approximation in order to keep accuracy. Thus, complex circuit, with several design/optimization degrees of freedom can also be considered. The expression of the step response, from the proposed methodology, is based on the DC bias operating point of the devices of the circuit. For this, complex and accurate device models (e.g. BSIM3v3) are integrated. During the optimization process, the time-domain evaluation of the amplifier is used by the genetic algorithm, in the classification of the genetic individuals. The time-domain evaluator is integrated into the developed optimization platform, as independent library, coded using C programming language. The genetic algorithms have demonstrated to be a good approach for optimization since they are flexible and independent from the optimization-objective. Different levels of abstraction can be optimized either system level or circuit level. Optimization of any new block is basically carried-out by simply providing additional configuration files, e.g. chromosome format, in text format; and the circuit library where the fitness value of each individual of the genetic algorithm is computed. Distributed processing is also employed to address the increasing processing time demanded by the complex circuit analysis, and the accurate models of the circuit devices. The communication by remote processing nodes is based on Message Passing interface (MPI). It is demonstrated that the distributed processing reduced the optimization run-time by more than one order of magnitude. Platform assessment is carried by several examples of two-stage amplifiers, which have been optimized and successfully used, embedded, in larger systems, such as data converters. A dedicated example of an inverter-based self-biased two-stage amplifier has been designed, laid-out and fabricated as a stand-alone circuit and experimentally evaluated. The measured results are a direct demonstration of the effectiveness of the proposed time-domain optimization methodology.Portuguese Foundation for the Science and Technology (FCT

Voice-Activated Smart Home Controller Using Machine Learning

UIDB/00066/2020The emergence of the Internet of Things concept has provided a great vision for the technological future, intending to enable the extraction and comprehension of information from the environment around us, making use of the interaction and cooperation between several technological devices. The example of Smart Homes, in particular, aims to integrate these devices into households, enabling the automation of tasks previously performed by humans, to simplify their daily lives and create a more comfortable environment. However, many of these devices fail to keep their promise, since they were not developed taking into account the frequent change of habits and tastes of the user, being necessary reprogramming of the device to follow the new behaviors. Taking this problem into account, this article presents the design and end-to-end implementation of a voice-activated smart home controller for intelligent devices, deployed in a real environment and validated in an experimental setup of motorized blinds. The architecture of the proposed solution integrates evolvable intelligence with the use of an Online Learning framework, enabling it to automatically adapt to the user's habits and behavioral patterns. The results obtained from the various evaluation tests provide a validation of the operation and usefulness of the developed system. The main contributions of this work are: I) design of a smart home controller's architecture; II) end-to-end implementation of a smart home controller and respective guidelines; III) open-source dataset of user behavior from the smart blinds scenario; IV) comparison between Online and Offline Learning approaches.publishersversionpublishe

Activity based budgeting : caso de estudo ADIRA, SA

Ao longo de muitos anos, as ferramentas de controlo de gestão têem vindo, cada vez mais, a fazer sentido nas empresas devido, essencialmente, à análise profunda e detalhada que estas práticas permitem. A volatilidade dos mercados, a globalização que torna a concorrência mais agressiva e a burocracia inerente aos negócios, torna as empresas mais adaptáveis e moldáveis à conjuntura atual. O orçamento é a ferramenta de controlo de gestão mais utilizada na ADIRA e, neste sentido, torna-se pertinente analisar com sentido crítico o processo de orçamentação e a viabilidade de implementação de uma nova prática de orçamentação. Assim sendo, esta dissertação divide-se em três grandes blocos. O primeiro bloco dedica-se ao estudo de teorias baseadas no processo de orçamentação e o estudo da prática Activity Based Budgeting. O segundo bloco pretende analisar o processo de orçamentação da ADIRA e o terceiro bloco pretende perceber a viabilidade de implementação de uma nova metodologia de orçamentação, mais concretamente o Activity Based Budgeting, expondo as próximas tarefas a executar para conclusão de implementação deste método e algumas propostas de melhoria acerca desta matéria. Os resultados comprovam que, no que diz respeito ao processo de orçamentação poderá haver algumas melhorias a executar nomeadamente no que toca ao planeamento orçamental. Em relação à utilização do método Activity Based Budgeting, para a ADIRA, faz todo o sentido a sua implementação com o objetivo de evidenciar a rentabilidade das diferentes áreas de negócios e as atividades que as suportam.For years, management control tools have been used by a growing number of companies. This is due mainly to the deep and detailed analysis that are possible to be made by these tools. The markets volatility, the globalisation that makes competition more aggresive, and the bureaucracies to which businesses are subject nowadays have been pressuring companies to adapt to the actual juncture. These days, budget is one of the most used and general practices in the business world. Given that, it has become relevant to critically analyze the budgeting process and the implementation of a new budgeting practice. Therefore, this dissertation is divided in three big parts. The first is related to the study of the theory behing the subject. On the other hand, on the second part, it is pretended t analyze the budgeting process on a specific company. Finally, on the third part, it is supposed to be understood how viable it is to implement a new budgeting methodology, namely the Actively Based Budgeting, exposing the next steps to execute in order to conclude the implementation of this method and some proposals of improvement on this subject. Regarding the budgeting process, the results prove that there is space to some improvements to execute, namely on the budget planning. Moreover, when it comes to the use of a method as Activity Based Budgeting, it makes sense to implement it in a company like ADIRA in order to highlight the different activities and business areas that support it

Point of care prehospital ultrasound in Basic Emergency Services in Portugal

Background and Aims: The Point of Care Ultrasound and Point‐of‐Care Ultrasound in Resource‐Limited Settings are differentiated diagnostic methods using ultrasound, essential in urgent patients screening, allowing better guidance in the diagnostic process and therapeutic approach. This study intends to observe the impact of these techniques in two Basic Emergency Services (SUB) in Portugal. Methods: A longitudinal study was carried out in two remote locations in Portugal (SUB N and SUB S). Data were collected by trained radiographers in each location, and a total of 972 exams were considered. Imaging findings were documented by exam type, the exam normality and the resolution after exam. χ 2 and Cramer's V tests were performed to check significant correlations between the variables. Results: Regarding the type of echographic findings, 289 (29.7%) were considered normal, 628 (64.6%) were classified as abnormal and 55 (5.7%) were considered inconclusive. As for the type of resolution, 58% had local resolution, 24% were referred to a hospital emergency service and 18% referred to ambulatory care. Regarding the Location versus Resolution after exam versus Findings variables, it was verified a stronger statistically significant association for the exams considered “Abnormal” (Cramer´s V = 0.414; p < 0.001). In the variables Location versus Findings versus Resolution after exam, it was verified a stronger statistical significance for “Referral to Ambulatory” (Cramer V = 0.443; p < 0.001) although Referral for Hospital (Cramer V = 0.252; p = 0.003) or Local Resolution (Cramer V = 0.252; p < 0.001) also had a moderate association strength. Conclusion: Ultrasonography is a useful diagnostic tool for patients screening, having an influence on patient management in remote settings. Given the limited literature in Portugal about this matter, further research and literature will be needed to support and complement the results of this study.info:eu-repo/semantics/publishedVersio

Three-dimensional modeling of tongue during speech using MRI data

The tongue is the most important and dynamic articulator for speech formation, because of its anatomic aspects (particularly, the large volume of this muscular organ comparatively to the surrounding organs of the vocal tract) and also due to the wide range of movements and flexibility that are involved. In speech communication research, a variety of techniques have been used for measuring the three-dimensional vocal tract shapes. More recently, magnetic resonance imaging (MRI) becomes common; mainly, because this technique allows the collection of a set of static and dynamic images that can represent the entire vocal tract along any orientation. Over the years, different anatomical organs of the vocal tract have been modelled; namely, 2D and 3D tongue models, using parametric or statistical modelling procedures. Our aims are to present and describe some 3D reconstructed models from MRI data, for one subject uttering sustained articulations of some typical Portuguese sounds. Thus, we present a 3D database of the tongue obtained by stack combinations with the subject articulating Portuguese vowels. This 3D knowledge of the speech organs could be very important; especially, for clinical purposes (for example, for the assessment of articulatory impairments followed by tongue surgery in speech rehabilitation), and also for a better understanding of acoustic theory in speech formation

The influence of bioclimate on soil microbial communities of cork oak

Background: Soil microbiomes are important to maintain soil processes in forests and confer protection to plants against abiotic and biotic stresses. These microbiomes can be affected by environmental changes. In this work, soil microbial communities from different cork oak Portuguese forests under different edaphoclimatic conditions were described by using a metabarcoding strategy targeting ITS2 and 16S barcodes. Results: A total of 11,974 fungal and 12,010 bacterial amplicon sequence variants (ASVs) were obtained, revealing rich and diverse microbial communities associated with different cork oak forests. Bioclimate was described as the major factor influencing variability in these communities (or bioclimates/cork oak forest for fungal community), followed by boron and granulometry. Also, pH explained variation of fungal communities, while C:N ratio contributed to bacterial variation. Fungal and bacterial biomarker genera for specific bioclimates were described. Their co-occurrence network revealed the existence of a complex and delicate balance among microbial communities. Conclusions: The findings revealed that bacterial communities are more likely to be affected by different edaphoclimatic conditions than fungal communities, also predicting a higher impact of climate change on bacterial communities. The integration of cork oak fungal and bacterial microbiota under different bioclimates could be further explored to provide information about useful interactions for increasing cork oak forest sustainability in a world subject to climate changes.This work was supported by FEDER funds through COMPETE (Programa Operacional Factores de Competitividade) and by national funds by FCT (Fundação para a Ciência e a Tecnologia) in the framework of the project POCI-01-0145- FEDER-028635, as well as for financial support to BioISI (UIDB/04046/2020), CBMA (UIDB/04050/2020) and CIMO (UID/AGR/00690/2020) by national funds by FCT/MCTES/PIDDAC. D. Costa thanks FCT for PhD grant SFRH/ BD/120516/2016 and COVID/BD/151779/2021.info:eu-repo/semantics/publishedVersio

Magnetic resonance imaging of the vocal tract: techniques and applications

Magnetic resonance (MR) imaging has been used to analyse and evaluate the vocal tract shape through different techniques and with promising results in several fields. Our purpose is to demonstrate the relevance of MR and image processing for the vocal tract study. The extraction of contours of the air cavities allowed the set - up of a number of 3D reconstruction image stacks by means of the combination of orthogonally oriented sets of slices for e ach articulatory gesture, as a new approach to solve the expected spatial under sampling of the imaging process. In result these models give improved information for the visualization of morphologic and anatomical aspects and are useful for partial measure ments of the vocal tract shape in different situations. Potential use can be found in Medical and therapeutic applications as well as in acoustic articulatory speech modelling

Macrofungi associated with sweet chestnut: a source of income for rural populations in Northeast of Portugal

European chestnut tree (Castanea sativa Mill.) has a great economic interest for wood and fruit production in northeast of Portugal. Over the last decade another important income associated with this culture has emerged - the collection and commercialization of wild edible mushrooms growing in chestnut orchards. Actually, despite the low knowledge of their biodiversity, ecology or sustainable management in those regions, mushrooms harvesting have been increasing, mainly due to their economic importance to local populations. In order to define the sustainability of this mycological resource, the study of diversity and production of macrofungi associated with chestnut tree was carried out. Commercial harvesting of edible mushrooms as a complementary income to local populations, was also evaluated, through chestnut associated mushroom production. The study was carried out from 2002 to 2005, in a non-tilled C. sativa orchard located in Oleiros – Bragança (Northeast of Portugal) (29T PG 80 9 36 UTM, 915 m above sea level), at Natural Park of Montesinho. Five quadrate plots of 100 m2 each were selected in the chestnut orchard, and all the sporocarps were weekly (autumn and spring) or biweekly (winter and summer) collected. No assessments were undertaken during January, February, March and August, since in this period few macrofungi produce sporocarps in Bragança. Sporocarps were identified by genera or species following standard procedures for taxonomic identification. For determining production, sporocarps were dried at 30ºC, for 72 h, and weighed (dw). Meteorological data was obtained from the weather station at Campus of Escola Superior Agrária de Bragança, located approximately 6 km of the studied C. sativa orchard. The diversity of macrofungi species was expressed by species richness (S), Simpson´s diversity index (D), total abundance (N) and relative abundance. The production of macrofungi (dry weight per hectare) was expressed for i) total species; ii) mycorrhizal and non-mycorrhizal species; iii) and edible and non-edible species. The economic income was only evaluated for the edible species sold in the local markets, namely Amanita caesarea, Boletus edulis, Boletus aereus, Cantharellus cibarius, Hydnum rufescens and Calocybe gambosa (Garcia et al., 2006). The value of mushrooms production was estimated taking into account the average current price of these species in the region in 2003. During the period of studies, 73 macrofungal species belonging to 16 family and 23 genera were identified. The greatest number of species belonged to the genera Russula (12), Inocybe (9), Lactarius (7), Tricholoma (6), Boletus (5), Cortinarius (5) and Amanita (5). The cumulative number of species, over the four successive years, revealed that 80.5% of macrofungal species that probably exist in this habitat were surveyed. The harvestings from 2002 and 2003 has contributed mostly to the number of species collected. Actually, the number of macrofungal species attained a maximum (56 species) in 2002 and a minimum (12 species) in 2005. Also, Simpson´s diversity index was significantly higher in 2002 (8.1 ± 0.98) than in the other years (3.9 ± 0.51 in 2003; 1.5 ± 0.15 in 2004; 1.1 ± 0.06 in 2005). About 46% of the macrofungal species has occurred in a single year. Only about 4% of the species has occurred in all de 4-years study, 25% in two years and 25% in three years. Fruiting phenology of macrofungal species and number of carpophores showed a bimodal pattern in each year, with one peak from late May to June (Spring season) and a more intense peak from September to early December (Autumn season). The greatest number of species (85% of the total registered) has occurred during Autumn season and only 11 species have occurred in both fruiting seasons (Spring and Autumn). A total of 2677 carpophores were harvested during the time course of this study. The higher number of carpophores was from the species Laccaria laccata (324), Hebeloma crustuliniforme (308) and Inocybe geophylla (303), which were also the most frequent species over the 4-year study period besides Russula lutea and Cortinarius helobius. The maximum number of carpophores was observed in 2003 (1514 carpophores) and the minimum in 2005 (138 carpophores). Also, the species richness and abundance were much lower in 2004 and especially in 2005, than in 2002 and 2003. These results were probably the effect from a severe drought period observed during all 2004 and 2005 in the Northeast of Portugal. The distribution of species by trophy groups revealed a dominance of mycorrhizal species (82%). About 49% of the identified species were edible and 29% were non-edible, the remaining being of unknown edibility. From the 36 identified edible species, only six are currently available in local markets. The total carpophores yield during the 4-year study period attained 67.6 kg dw/ha, from which 64.0 kg dw/ha were mycorrhizal species and 50.7 kg dw/ha were edible species. Lactarius piperatuts, Russula delica and Boletus edulis were the species that contributed most to the total yield (11.0 kg dw/ha, 8.0 kg dw/ha and 6.2 kg dw/ha, respectively). As observed for species richness and abundance, also the macrofungi yield reached a maximum (44.0 kg dw/ha) in 2002 and a minimum (2.3 kg dw/ha) in 2005. Only 20% of the total dry weight production of edible species refers to current available mushroom in local markets. Assuming the average current price of these species in the region in 2003, the total income associated with these species was 134 €/ha and per year: A. caesarea (3.5 €/ha), B. edulis (59.4 €/ha), B. aereus (18.2 €/ha), C. cibarius (39.8 €/ha), H. rufescens (3.7 €/ha) and C. gambosa (9.0 €/ha). These results suggest that commercial harvesting of these edible mushrooms could be an additional source of income for chestnut producers with significant contribution to regional economies. However, over picking has to be avoided, as conservation and management strategies are required. In fact, it is important that these habitats will be managed under an ecosystem management philosophy that entails multiple-use. For this purpose it is still necessary to study mushroom harvesting effects in the ecosystem and the effects of management practices (namely tillage or non tillage) on the occurrence, production and reproduction of mushrooms. To improve mushroom management it will also necessary to understand their biology and ecology, and perform mushrooms surveys over multiple fruiting seasons.European chestnut tree (Castanea sativa Mill.) has a great economic interest for wood and fruit production in northeast of Portugal. Over the last decade another important income associated with this culture has emerged - the collection and commercialization of wild edible mushrooms growing in chestnut orchards. Actually, despite the low knowledge of their biodiversity, ecology or sustainable management in those regions, mushrooms harvesting have been increasing, mainly due to their economic importance to local populations. In order to define the sustainability of this mycological resource, the study of diversity and production of macrofungi a ssociated with chestnut tree was carried out.The authors ore grateful to AGRO Project 689 for financial support of this work