The novel contribution of the thesis is the design and implementation of decentralised output feedback power system controllers for power oscillation damping (POD) over the entire operating regime of the power system. The POD controllers are designed for the linearised models of the nonlinear power system dynamics. The linearised models are combined and treated as parameter varying switched systems. The thesis contains novel results for the controller design, bumpless switching and stability analysis of such switched systems. Use of switched controllers against the present trend of having single controller helps to reduce the conservatism and to increase the uncertainty handling capability of the power system controller design. Minimax-LQG control design method is used for the controller design. Minimax-LQG control combines the advantages of both LQG and H control methods with respect to robustness and the inclusion of uncertainty and noise in the controller design. Also, minimax-LQG control allows the use of multiple integral quadratic constraints to bound the different types of uncertainties in the power system application. During switching between controllers, switching stability of the system is guaranteed by constraining the minimum time between two consecutive switchings. An expression is developed to compute the minimum time required between switchings including the effect of jumps in the states. Bumpless switching scheme is used to minimise the switching transients which occur when the controllers are switched. Another contribution of the thesis is to include the effect of on load tap changing transformers in the power system controller design. A simplified power system model linking generator and tap changing transformer dynamics is developed for this purpose and included in the controller design. The performance of the proposed linear controllers are validated by nonlinear computer simulations and through real time digital simulations. The designed controllers improve power system damping and provide uniform performance over the entire operating regime of the generator.

<p>The study catered for empirical and metaphysical dimensions of science and IKS. The study employed a quasi-experimental design as well as a qualitative research design. Two cohorts of students from a fictitiously named &ldquo / Culture Secondary School&rdquo / have been used in this study. The list of instruments for data collection were as follows: Conceptions of Fermentation (COF) questionnaire which was used to elicit learners&rsquo / pre- and post-test conceptions of fermentation with special reference to traditional beer or &ldquo / Umqombothi&rdquo / , an Attitudes to Science (ATS) questionnaire which was used to find out the learners&rsquo / worldviews, a Science Achievement Test (SAT) which was used to assess the learners&rsquo / generalised knowledge of fermentation, a classroom observation schedule as well as a focus group interview schedule to gather additional qualitative data. All the instruments were in English with all technical and difficult terms in both English and isiXhosa (the learners&rsquo / home language). Both groups were exposed to Science/IKS-based lessons. The only difference between the two groups was that, the experimental group (E group) was exposed to a Dialogical Argumentation Teaching Model (DAIM) and the comparison group (C group) to a traditional teaching approach. The data gatherred were both analyzed in terms of qualitative and quantitative descriptions.</p>

<p>The study catered for empirical and metaphysical dimensions of science and IKS. The study employed a quasi-experimental design as well as a qualitative research design. Two cohorts of students from a fictitiously named &ldquo / Culture Secondary School&rdquo / have been used in this study. The list of instruments for data collection were as follows: Conceptions of Fermentation (COF) questionnaire which was used to elicit learners&rsquo / pre- and post-test conceptions of fermentation with special reference to traditional beer or &ldquo / Umqombothi&rdquo / , an Attitudes to Science (ATS) questionnaire which was used to find out the learners&rsquo / worldviews, a Science Achievement Test (SAT) which was used to assess the learners&rsquo / generalised knowledge of fermentation, a classroom observation schedule as well as a focus group interview schedule to gather additional qualitative data. All the instruments were in English with all technical and difficult terms in both English and isiXhosa (the learners&rsquo / home language). Both groups were exposed to Science/IKS-based lessons. The only difference between the two groups was that, the experimental group (E group) was exposed to a Dialogical Argumentation Teaching Model (DAIM) and the comparison group (C group) to a traditional teaching approach. The data gatherred were both analyzed in terms of qualitative and quantitative descriptions.</p>

For water suppliers, using chlorine is necessary to ensure water bacteriological quality from the treatment plant to the consumers' tap. However, chlorine flavour is one of the most common reasons advocated for choosing tap water alternatives as drinking water. As a consequence, the putative link between chlorine flavour perception and tap water consumption is an issue in drinking water habits studies. Since the sensory mechanisms involved in chlorine flavour perception remained largely unknown, the main objective of this thesis work was to first highlight those mechanisms and then to identify potential lever chlorine flavour sensory neutralisation.In a first step, we demonstrated that hypochlorous acid associated, which is likelyresponsible of chlorine flavour in tap water, could activate the olfactory system at low concentrations and the trigeminal system for concentrations up to 4 mg/L Cl2. Additionally, our results suggested that tap water consumption does not seem to be related to sensitivity to chlorine flavour but rather to consumers' tap water representation.In a second stage, we explored the impact of water mineral matrix on chlorine flavour perception. We demonstrated first that water molarity and cationic content variations modulate drinking water taste. We also evidenced that chlorine flavour intensity is modulated according to water composition. Nevertheless, our data suggest that physico-chemical, in- mouth physiological and sensory mechanisms are likely involved in such modulation.In the last part of the Thesis work, we investigate the putative influence of aroma perceptionon chlorine flavour. Our results showed that beyond chemical reactions between hypochlorous acid and odorants, aromas at peri-threshold concentration enhance chlorine flavour and decrease tap water acceptability

Syftet med det här examensarbetet var att undersöka 3-5 åringars förmåga att utveckla sin förståelse för vattnets väg till kranen genom med en pedagogisk aktivitet. Genom den pedagogiska aktiviteten gavs barnen möjlighet att färdas genom vattensystemet med sina kroppar och sinnen, från sjön till kranen. För att kartlägga hur barnens förståelse utvecklats genomfördes kvalitativa intervjuer före och efter den pedagogiska aktiviteten.Jämförelsen mellan resultaten av förintervjuerna och uppföljningsintervjuerna pekar på en tydlig utveckling av barnens förståelse av vattnets väg till kranen, som ett tekniskt system. Flera av barnen utvecklade sin förståelse för att vårt hushållsvatten måste genomgå en reningsprocess, färdas genom olika komponenter i vattensystemet och rör innan det slutligen når kranen och kan förtäras. / The purpose with this degree thesis was to examine 3-5 year old´s ability to develop their understanding of the path of the water to the tap through an educational activity. Through the educational activity the children was given the opportunity to travel through the water system with their bodies and senses, from the lake to the tap. Qualitative interviews were carried out before and after the educational activity to map out the children´s understanding and how it had developed after the educational activity.The comparison between the results of the pre-interviews and follow-up interviews indicate a clear development of the children´s understanding of the path of water to the tap, as a technical system. Several of the children developed the understanding that our domestic water must undergo a purification process, travel through various components of the water system and pipes before it finally reaches the tap and can be ingested.

Unlike Canadian English which has two liquid consonant phonemes, /ɹ, l/ (as in right and light), Japanese is said to have a single liquid phoneme whose realization varies widely both among speakers and within the speech of individuals. Although variants of the /r/ sound in Japanese have been described as flaps, laterals, and weak plosives, research that has sought to quantitatively describe this phonetic variation has not yet been carried out. The aim of this thesis is to provide such quantification based on 1,535 instances of /r/ spoken by four individuals whose near-natural, unscripted conversations had been recorded as part of a larger corpus of unscripted Japanese maintained by Dr. Nick Campbell of Advanced Telecommunications Research Institute International (ATR), Kyoto, Japan. Tokens of /r/ were extracted from 30-minute conversations between one pair of male speakers and one pair of female speakers. Each token was narrowly transcribed into the International Phonetic Alphabet, then categorized based on the author’s perception of: 1) the strength/narrowness of central oral articulatory stricture, and 2) the presence or absence of an auditory-perceptual lateral and/or rhotic sound quality. Transcription and category frequencies for each speaker averaged across all environments were then compared with frequencies in specific phonological environments to ascertain whether a particular environment was amenable to a ‘drift’ towards any particular category of variant, and whether patterns of ‘drift’ applied to all speakers or varied on an individual basis. Transcriptions of the 1,535 tokens of /r/ ranged widely among lateral and non-lateral flaps, raised (i.e. increased articulatory contact) non-lateral flaps akin to light voiced plosives (e.g. Hattori 1951, Kawakami 1977), as well as lateral approximants and rhotic approximants. While two of the four speakers, both males, patterned similarly by dividing their productions of /r/ chiefly among short lateral approximants and rhotic approximants, each speaker did vary considerably in their choice of variants in any given environment. Drift is considered in terms of physiological parameters which may be optionally exploited to maintain phonological salience.

This dissertation applies theories and concepts of wireless communications and signal processing to the security domain to assess the security of a Wireless secret Key Generation (WKG) system against capable eavesdroppers, who employ all the feasible tools to compromise the system’s security. The security of WKG is evaluated via real wireless measurements, where adversary knows and applies appropriate signal processing tools in ordere to predict the generated key with the communicating pair. It is shown that in a broadband stationary wireless communication channel, (e.g. commercial off-the-shelf 802.11 WLAN devices), a capable eavesdropper can recover a large portion of the secret key bits. However, in an Ultra-wideband (UWB) communication, at the same stationary environment, secret key rates of 128 bits per channel probe are achievable. / Graduate

Voltage imbalance in low voltage (LV) networks is expected to deteriorate as low carbon technologies, e.g. electric vehicles (EVs) and heat pumps (HPs) are increasingly deployed. The new electrical demand attributable to EVs and HPs would increase the voltage magnitude variation, increasing the possibility of voltages moving outside the statutory LV magnitude limits. Moreover, the single-phase nature of EVs and HPs, which will be connected via a single-phase 'line &amp; neutral' cable to a 3-phase four-wire LV mains cable buried beneath the street, further entangles this voltage management problem; the non-balanced voltage variations in the three phases boost the levels of voltage imbalance. Excessive voltage imbalance and magnitude variation need to be mitigated to limit their adverse effects on the electric network and connected plant. The voltage imbalance in LV networks is conventionally reduced by reinforcing the network, generally at a high cost. Some modern methods for voltage imbalance mitigation have been introduced in recent years. The power electronic converter based methods are inadequate due to the generation of harmonics, significant power losses and short lifetime. Besides, automatic supply phase selection and smart EV charging rely on an advanced smart communication system, which currently is not available. This project aims to develop alternative solutions that mitigate the voltage imbalance seen in LV networks. A voltage balancing method based on Scott transformer (ST) is proposed. This method does not generate harmonics and is independent of the smart communication system. Computer simulations demonstrated the proposed method is able to convert a non-balanced 3-phase voltage into a balanced 3-phase voltage at either a point on the LV feeder or a 3-phase load supply point with the predefined voltage magnitude. Besides, a physical voltage balancing system was created based on the proposed method and it was tested in an LV network in the laboratory. The test results show the balancing system is capable of maintaining a low level of voltage imbalance on the LV feeder by rapidly compensating for the voltage rises and sags caused by single-phase load variations. This voltage balancing method is a potential solution for the network utilities to accommodate the significant penetration of low carbon technologies without breaching the network voltage limits. The impact of EVs and HPs on the LV network voltages is investigated based on a Monte Carlo (MC) simulation platform, which comprises a statistical model of EV charging demand, profiles generators of residential and HP electrical demand, and a distribution network model. The MC simulation indicates the impact of EVs and HPs is related to their distribution; when more than 21EVs and 13HPs are non-evenly distributed on a 96-customer LV feeder, the voltage limits are likely to be violated. Moreover, the effectiveness of the ST based voltage balancing method and the demand response based TOU tariff, implemented either alone or together, in mitigating the impact of EVs and HPs is investigated based on the established MC simulation platform. The results indicate the ST based balancing method alone is able to completely mitigate the voltage limit violations regardless of the penetration levels of EVs and HPs. Moreover, using both of the two investigated methods further enhances the balancing effectiveness of the ST based voltage balancing method.

Esta pesquisa ocupa-se em investigar, à luz da Teoria da Variação laboviana, o emprego de tepe em lugar de vibrante em onset silábico na fala da comunidade bilíngue (português-italiano) de Flores da Cunha (RS), alternância que não se verifica na fala de monolíngues-português. Utilizaram-se dados de dois bancos, VARSUL e BDSer, levantados de entrevistas realizadas em 1990 e 2009, o que possibilitou fazer um estudo em tempo real. A análise da fala de 40 informantes, 20 de cada banco, revelou um decréscimo na frequência total de aplicação da regra: 41% nos dados do VARSUL, 31% nos do BDSer, indício de regressão da regra. Na análise em tempo real, estudo de tendência, observou-se semelhança no papel favorecedor ou desfavorecedor das variáveis controladas, exceto no que diz respeito à variável Idade. O estudo de painel mostrou que os informantes diminuíram a aplicação da regra com o passar dos anos, o que contraria a expectativa de estabilidade do padrão linguístico da fala adulta. / This is a research about the use of tap where a trill is expected in Brazilian Portuguese, which does not occur in the speech of monolinguals, but can be verified in the speech of Portuguese-Italian bilinguals who live in the city of Flores da Cunha (Rio Grande do Sul, Brazil). The analysis follows the Theory of Language Variation, by William Labov. The data come from two different sources, VARSUL and BDSer data banks, which have sociolinguistic interviews recorded in 1990 and 2009. This fact enabled us to carry out a real time study. The analysis of the speech of 40 informants, 20 from each bank, showed a decrease in the total frequency of rule application: 41% in the speech of VARSUL informants, 31% in the speech of BDSer informants, a sign of rule regression. The real time analysis, tendency study, showed that the role of the variables under control has not changed along 20 years, except the role of the variable Age. The pannel study showed a decrease in rule application by the three informants studied. This goes against the expectation of a stable linguistic behavior in adult speech.

Esta tese objetiva analisar processos de variação linguística em tempo real (LABOV, 1994) no português brasileiro de contato com variedades dialetais italianas, para verificar se existe coerência dialetal (GUY e HINSKENS, 2016) na comunidade de Flores da Cunha (RS). Para tanto, fizemos análise quantitativa conforme metodologia de análise de regra variável (LABOV, 1972), para cotejar o padrão de variação de -ão::-on em tempo real com o de outro processo na mesma comunidade. A pesquisa foi embasada em dados de fala provenientes de dois acervos distintos, o do projeto VARSUL (1990) e do Projeto BDSer (2008/2009). Na „troca‟ de -ão por –on, houve um decréscimo na frequência total de aplicação da regra variável: 30,7% nos dados do VARSUL e 21,6% nos do BDSer, indício de regressão de regra. Para verificar a existência de coerência dialetal, compararam-se os resultados da análise de ão::on com os do estudo de Azeredo (2012), sobre o uso variável de tepe em lugar de vibrante no português de contato com variedades dialetais italianas e observamos que as variantes atribuídas ao contato são, ambas, favorecidas pelos homens de mais idade e com nível mais baixo de escolaridade. Essa correlação entre as variáveis analisadas aponta para a existência de coerência dialetal na comunidade de fala em estudo. / This thesis aims at analyzing linguistic variation processes in real time (LABOV, 1994) in Brazilian Portuguese in contact with Italian dialectal varieties, to verify if there is lethal coherence (GUY and HINSKENS, 2016) in the community of Flores da Cunha (RS). We performed a quantitative analysis according to the methodology of variable rule analysis (LABOV, 1972), to compare the variation pattern of -ão::-on in real time with that of another process in the same community. Our research was based on speech data from two different collections, the VARSUL project (1990) and the BDSer Project (2008/2009). The analysis showed a decrease in the total frequency of use of -on in contexts where -ão is expected: 30.7% in the speech of VARSUL informants and 21.6% in the speech of BDSer informants, a sign of rule regression. We compared the results of the analysis of -ão::-on with the results of Azeredo (2012) about the use of tap where a trill is expected. We observed that older men with low level of schooling favor the variants under analysis. The correlation between the analyzed variables points to the existence of lethal coherence in the speech community under study.