While a lot of time and resources have been placed into transceiver design, due to the pace of a conventional engineering design process, the design of a power amplifier is often completed using scattered resources; and not always in a methodological manner, and frequently even by an iterative trial and error process. In this thesis, a research question is posed which enables for the investigation of the possibility of streamlining the design flow for power amplifiers. After thorough theoretical investigation of existing power amplifier design methods and modelling, inductors inevitably used in power amplifier design were identified as a major drawback to efficient design, even when examples of inductors are packaged in design HIT-Kits. The main contribution of this research is engineering of an inductor design process, which in-effect contributes towards enhancing conventional power amplifiers. This inductance search algorithm finds the highest quality factor configuration of a single-layer square spiral inductor within certain tolerance using formulae for inductance and inductor parasitics of traditional single-π inductor model. Further contribution of this research is a set of algorithms for the complete design of switch-mode (Class-E and Class-F) power amplifiers and their output matching networks. These algorithms make use of classic deterministic design equations so that values of parasitic components can be calculated given input parameters, including required output power, centre frequency, supply voltage, and choice of class of operation. The hypothesis was satisfied for SiGe BiCMOS S35 process from Austriamicrosystems (AMS). Several metal-3 and thick-metal inductors were designed using the abovementioned algorithm and compared with experimental results provided by AMS. Correspondence was established between designed, experimental and EM simulation results, enabling qualification of inductors other than those with experimental results available from AMS by means of EM simulations with average relative errors of 3.7% for inductors and 21% for the Q factor at its peak frequency. For a wide range of inductors, Q-factors of 10 and more were readily experienced. Furthermore, simulations were performed for number of Class-E and Class-F amplifier configurations with HBTs with ft greater than 60 GHz and total emitter area of 96 μm² as driving transistors to complete the hypothesis testing. For the complete PA system design (including inductors), simulations showed that switch-mode power amplifiers for 50 Ω load at 2.4 GHz centre frequency can be designed using the streamlined method of this research for the output power of about 6 dB less than aimed. This power loss was expected, since it can be attributed to non-ideal properties of the driving transistor and Q-factor limitations of the integrated inductors, assumptions which the computations of the routine were based on. Although these results were obtained for a single micro-process, it was further speculated that outcome of this research has a general contribution, since streamlined method can be used with a much wider range of CMOS and BiCMOS processes, when low-gigahertz operating power amplifiers are needed. This theory was confirmed by means of simulation and fabrication in 180 nm BiCMOS process from IBM, results of which were also presented. The work presented here, was combined with algorithms for SPICE netlist extraction and the spiral inductor layout extraction (CIF and GDSII formats). This secondary research outcome further contributed to the completeness of the design flow. All the above features showed that the routine developed here is substantially better than cut-and-try methods for design of power amplifiers found in the existing body of knowledge. / Thesis (PhD(Eng))--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / unrestricted

Syftet med den här uppsatsen har varit att undersöka vilka diskurser som motiverar s.k. cancelkultur i ett givet fall. Cancelkultur saknar i skrivande stund en definition men använts som avbrott i stöd till följd av en persons problematiska uttalanden. Undersökningen har utförts genom en kvalitativ textanalys av ”JK Rowling’s Anti-Transgender Stance And Hogwarts Legacy” där särskilt fokus legat på att kritiskt analysera de diskurser som redan identifierats om cancelkultur i tidigare forskning. I den kvalitativa textanalysen identifierades cancelkulturens egenskaper ur materialet genom tolkande beskrivning för att sedan kontextualiseras och kritiskt analyseras i diskussionsavsnittet. De huvudsakliga data som framkom av materialet var att cancelkultur motiveras av maktobalans, vi och dem narrativ och avkontextualisering genom individualisering. Maktobalans visade sig vara den främsta faktorn som motiverade de diskurser som i övrigt togs upp i materialet vilket föranledde att särskilt fokus lades på att diskutera maktpositioner och tillhörande vanor utifrån materialet. Det visade sig i enighet med tidigare forskning att maktobalansen driver cancelkulturen då de som blir cancelled anses missbruka sina maktpositioner och möjligheten att ”cancela” någon ger möjlighet till marginaliserade grupper att tala ut mot de som antar problematiska vanor av makt. Materialets data diskuterades också utifrån uppfattningen om allmänåsikt i förhållande till viljan att tala ut för att undersöka om det fanns en koppling mellan cancelkulturen i det här fallet och viljan att tala ut mot transfobi. Diskussionen kom fram till att både transaktivister och anti-transaktivister antagligen uppfattade att de var i majoritet på grund av debattens polarisering och hade därför lika stor vilja att tala ut.

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The thesis focuses on discussions under news articles shared by news servers on the social network Facebook. The aim of this work is to summarize the existing understanding of the topic. Therefore, theoretical concepts connected to the topic are summarized. The thesis focuses on communication, online communication and the presence of news servers on social networks, as well as on the topic of anonymity on social networks and how anonymity can affect discussions. A chapter of the thesis focuses on the spiral of silence and its possible occurrence in discussions. Further, the thesis focuses on the freedom of speech as well as the new ways social networks are trying to fight disinformation and hate online. The empirical part focuses on how Facebook users view the use of social networks by news servers. Another part of the thesis focuses on a group of volunteers called #jsmetu. This group tries to make sure discussions are factual and are free from personal attacks and vulgarity. Three discussions are analysed - discussions #jsmetu took part in. The thesis investigates the influence #jsmetu has on discussions. Due to the topic of the thesis being a very current one, the thesis suggests more areas for further research.

Rapid growth in the field of communications industry has led to newer opportunities and challenges in the design of CMOS based monolithic integrated circuits. ASK modulators are a class of digital modulators which are known for their relative simplicity of implementation for low cost applications in the industrial and biomedical domains. This thesis presents a LC-based CMOS Amplitude Shift Keying (ASK) modulator scheme which demonstrates promising capability for radio frequency designs. This work describes the design and implementation of differential cross-coupled NMOS only LC power oscillator with ASK modulation to operate at 2.4 GHz frequency. In this work, 65nm CMOS process technology has been used for implementation. The work mainly focused on system parameters such as oscillation frequency, output signal power, power consumption and phase noise. The LC tank was created with a centre-tap on-chip differential spiral inductor and a Metal Insulator Metal (MIM) capacitor. The method of a current mirror with switching technique is employed for biasing the LC oscillator as well as ASK modulation output. The oscillator circuit has been optimised by using a simulation based approach to study the design and measurements to gain a greater insight into the performance of the ASK modulator. An output signal power of -1.59dBm at 2.30 GHz with a phase noise of -115.39dBc/Hz@1MHz and a power consumption of 5.92mW has been achieved at the layout level. Optimal ASK modulated output performance has been obtained for the data rate of up to around 40Mbits/s. In this thesis, simulation results have been presented for both the schematic and the layout levels.

This thesis's purpose was to gain a deeper understanding of how organizations create knowledge retention (KR), both proactively (day-to-day basis) and reactively (when an employee decides to resign), to avoid knowledge loss. A qualitative multiple case study was conducted through semi-structured interviews, with eight respondents from eight different organizations. An analytical model based on Levy’s (2011) KR framework and Nonaka and Takeuchi's (1995) knowledge spiral model was developed as a tool to understand the KR process in practice. The study found that all studied organizations worked proactively to retain knowledge, either structured or unstructured. The respondents with a structured, proactive KR process did not apply a reactive KR process, showing that they are more prepared for handling potential knowledge loss when employees resign. The respondents that did not apply a structured, proactive KR process applied a reactive knowledge retention process, where the main explanation for this was lack of time or unawareness of the process. Furthermore, no clear groups emerged in the empirical material as the companies faced different challenges at each stage of the analytical model. Lastly, the study concludes that these findings could be particularly relevant for organizations seeking to conduct KR processes to avoid losing valuable knowledge.

This thesis consists of four research papers presenting a microdata analysis approach to assess and evaluate the Parkinson’s disease (PD) motor symptoms using smartphone-based systems. PD is a progressive neurological disorder that is characterized by motor symptoms. It is a complex disease that requires continuous monitoring and multidimensional symptom analysis. Both patients’ perception regarding common symptom and their motor function need to be related to the repeated and time-stamped assessment; with this, the full extent of patient’s condition could be revealed. The smartphone enables and facilitates the remote, long-term and repeated assessment of PD symptoms. Two types of collected data from smartphone were used, one during a three year, and another during one-day clinical study. The data were collected from series of tests consisting of tapping and spiral motor tests. During the second time scale data collection, along smartphone-based measurements patients were video recorded while performing standardized motor tasks according to Unified Parkinson’s disease rating scales (UPDRS). At first, the objective of this thesis was to elaborate the state of the art, sensor systems, and measures that were used to detect, assess and quantify the four cardinal and dyskinetic motor symptoms. This was done through a review study. The review showed that smartphones as the new generation of sensing devices are preferred since they are considered as part of patients’ daily accessories, they are available and they include high-resolution activity data. Smartphones can capture important measures such as forces, acceleration and radial displacements that are useful for assessing PD motor symptoms. Through the obtained insights from the review study, the second objective of this thesis was to investigate whether a combination of tapping and spiral drawing tests could be useful to quantify dexterity in PD. More specifically, the aim was to develop data-driven methods to quantify and characterize dexterity in PD. The results from this study showed that tapping and spiral drawing tests that were collected by smartphone can detect movements reasonably well related to under- and over-medication. The thesis continued by developing an Approximate Entropy (ApEn)-based method, which aimed to measure the amount of temporal irregularity during spiral drawing tests. One of the disabilities associated with PD is the impaired ability to accurately time movements. The increase in timing variability among patients when compared to healthy subjects, suggests that the Basal Ganglia (BG) has a role in interval timing. ApEn method was used to measure temporal irregularity score (TIS) which could significantly differentiate the healthy subjects and patients at different stages of the disease. This method was compared to two other methods which were used to measure the overall drawing impairment and shakiness. TIS had better reliability and responsiveness compared to the other methods. However, in contrast to other methods, the mean scores of the ApEn-based method improved significantly during a 3-year clinical study, indicating a possible impact of pathological BG oscillations in temporal control during spiral drawing tasks. In addition, due to the data collection scheme, the study was limited to have no gold standard for validating the TIS. However, the study continued to further investigate the findings using another screen resolution, new dataset, new patient groups, and for shorter term measurements. The new dataset included the clinical assessments of patients while they performed tests according to UPDRS. The results of this study confirmed the findings in the previous study. Further investigation when assessing the correlation of TIS to clinical ratings showed the amount of temporal irregularity present in the spiral drawing cannot be detected during clinical assessment since TIS is an upper limb high frequency-based measure.

Spiral-artery (SA) remodeling is a fundamental process during pregnancy that involves the action of cells of the initial vessel, such as vascular smooth-muscle cells (VSMCs) and endothelial cells, but also maternal immune cells and fetal extravillous trophoblast cells (EVTs). Mast cells (MCs), and specifically chymase-expressing cells, have been identified as key to a sufficient SA remodeling process in vivo. However, the mechanisms are still unclear. The purpose of this study is to evaluate the effects of the MC line HMC-1 and recombinant human chymase (rhuCMA1) on human primary uterine vascular smooth-muscle cells (HUtSMCs), a human trophoblast cell line (HTR8/SV-neo), and human umbilical-vein endothelial cells (HUVEC) in vitro. Both HMC-1 and rhuCMA1 stimulated migration, proliferation, and changed protein expression in HUtSMCs. HMC-1 increased proliferation, migration, and changed gene expression of HTR8/SVneo cells, while rhuCMA treatment led to increased migration and decreased expression of tissue inhibitors of matrix metalloproteinases. Additionally, rhuCMA1 enhanced endothelial-cell-tube formation. Collectively, we identified possible mechanisms by which MCs/rhuCMA1 promote SA remodeling. Our findings are relevant to the understanding of this crucial step in pregnancy and thus of the dysregulated pathways that can lead to pregnancy complications such as fetal growth restriction and preeclampsia.

two towers: vertical library with spiral ramp

[pt] Esta pesquisa em comunicação política analisou o impacto das mídias digitais na opinião pública durante os protestos de 2019 em Hong Kong com base na hipótese da espiral do silêncio (Noelle-Neumann, 1974). Se trata de um estudo qualitativo e interpretativo que observa como os usuários participam das discussões políticas por meio das mídias sociais. A pesquisa procura analisar as opiniões e expressões em torno de o tema em estudado, privilegiando o estudo de caso e adotando métodos como a análise de enquadramentos e de conteúdo. Em concreto, questiona-se se nos protestos de 2019 em Hong Kong, ocorreu um fenômeno da espiral do silêncio nos debates sobre os protestos de 2019 em Hong Kong, nos comentários sobre as notícias postadas na página oficial no Facebook do South China Morning Post. Para responder à esta questão, este estudo analisou manualmente 76 notícias postadas pela fanpage e 2.000 comentários às mesmas. A teoria da Espiral do Silêncio afirma que pessoas que se reconhecem como minorias evitam expressar o que pensam publicamente, quando pensam que o clima de opinião da maioria é contrário às suas próprias opiniões. Os resultados desta pesquisa mostram que nos comentários da fanpage analisada, uma minoria de usuários tendeu a se autocensurar com o passar do tempo, confirmando a hipótese da espiral do silêncio, mas que após um certo período, voltou a expressar suas opiniões apesar de continuarem sendo uma minoria, o que evidencia uma espiral do silêncio intermitente no tempo, provavelmente motivada por fatores exógenos ao ambiente de discussão observado. A pesquisa visa contribuir para o avanço da discussão sobre participação política nas mídias sociais na atualidade, por meio do estudo do ambiente e do conteúdo midiático. O contexto do objeto da pesquisa é o do Projeto de Lei de Extradição de Hong Kong em 2019. Este estudo tem um significativo caráter inovador no Brasil, pois enriquece o repertório de pesquisas empíricas sobre os países asiáticos, ainda incipiente na comunicação política, fornecendo novos achados que incentivam futuras pesquisas em perspectiva comparada, utilizando teorias já consolidadas. / [en] This political communication research analyzed the impact of digital media on public opinion. This is a qualitative and interpretive study that observes how users participate in political discussions through social media. The survey aims to analyze the opinions and expressions surrounding the proposed theme, using case study as a research strategy, and adopting methods such as frame methods and qualitative content analysis. Starting from this concept, question are raised: In the 2019 Hong Kong protests, existed a Spiral of silence phenomenon on social media? This research has important scientific and innovative contributions. In order to understand these issue, based on the Spiral of silence hypothesis, this study manually analyzed 76 posts on the Facebook website of the South China Morning Post and 2,000 public comments. The development of the theory Spiral of silence (Noelle-Neumann, 1974) pointed out that people retain their opinions when they think that the climate of opinion is contrary to their own opinions, and this silence will increase over time. The analysis of this research shows that on the Facebook platform, a minority of opinion holders tend to retain their opinions, but as time goes by, a minority of determined people begin to express their opinions, which shows an intermittent Spiral of silence in time, probably motivated by factors exogenous to the observed discussion environment. The research aims to contribute to the advancement of the environment for public political participation on the current social media, through the study of the media environment and media content. The background of the research is the Hong Kong Anti-Extradition Law Amendment Bill movement. This special background has innovative significance, enriching empirical research on Eastern countries, and providing new ideas for non-campaigns political participation research.