The polarization of light is one of the most remarkable phenomena in nature and has led to many discoveries in the optical-telecommunications sphere. The master's thesis describes the basic knowledge about polarized light, which includes the types of light polarization, the issue of Poincaré sphere, polarizing ellipse, etc. Emphasis is also placed on the measurement of optical power, where the analysis of various types of photodetectors and also polarimeters was performed. In the practical part of this work, the design of the workplace itself is described in the diagrams. Also, all devices in the workplace are analyzed and subsequently demonstrated measurement in several scenarios. The final chapter is a discussion with the measured results and graphical dependencies, comparison and analysis of results.

Diploma thesis deals with polarization properties of an optical beam and the determination of its polarization state by means of the proposed automatic measurement method. Furthermore the influence of an environment on the polarization state of the optical wave is studied. At the beginning of this thesis the fundamental terms with respect to the wave polarization including the description of the polarization devices are presented. In conclusion a method for an automated experimental workplace for the measurement of the polarization properties using Poincare sphere and Stokes parameters is designed and verified.

This thesis examines the role of online platforms in relation to anti-progressive counterpublic dynamics. Counterpublicsare understood as alternative discursive arenas that form in response to exclusion from the wider public sphere. The relevance of counterpublics derives both from their ability to influence mainstream political discourse and from how anti-progressive counterpublics have been found to contribute to real-life violence. As the internet becomes an increasingly important venue for political discussion and contestation, the public sphere is extended online. This study explores how platforms can be seen as enabling (or constraining) the dual function of online counterpublics, i.e. as both inward and outward-oriented in relation to opposing publics, by examining the anti-feminist online community known as “Men Going Their Own Way” (MGTOW). The role of platforms is understood in terms of platform affordances, and netnographic methods were used to study these in relation to two online platforms. The results show that the two platforms presented different opportunities for the MGTOW counterpublic to some extent, suggesting that this counterpublic is able to utilise platforms for different purposes. Twitter was found to be particularly suitable for the outward-oriented function, i.e. for interacting with and opposing other publics, while mgtow.com was shown to be fertile ground for the inward-oriented function, and in that sense enabled contact between members in a way that contributed to the development of anti-progressive counterdiscourse.

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The purpose of this study is to examine users ́ opinions regarding the Swedish management of the covid-19 pandemic in two echo chambers, consisting of the comment fields in two ideologically different news pages on Facebook, Aftonbladet and Samtiden. Using a quantitative content analysis in different steps, the study will attempt to answer the following questions: - What opinions are expressed in two eco-chambers regarding the pandemic management in Sweden? -To what extent are these common or not between the echo chambers? The empirical material consists a total of 696 comments which will be analysed and compiled into a result. The result will then be set against two opposing theories, the theory of the Public Sphere and the theory of echo chambers, where these disagree upon whether the two different news pages lead to polarization. Depending on the outcome, the result can be said to be in agreement with one or both of the theories. The result of the study shows that the opinions of the users in the echo chambers are mainly the same which supports the theory of the Public Sphere and the idea of a need for a common consensus in order to maintain a functioning democracy. The opinions concern the subjects Sweden, the Swedish government, the Swedish state epidemiologist Anders Tegnell, the Restrictions and statistic rapports about the death toll in Sweden. The results provide information about the effects of echo chambers in an ongoing pandemic and the overall complexity around the definition of the term.

Dans les télécommunications, le débit-fiabilité et la complexité de l’encodage et du décodage (opération à virgule flottante-flops) sont largement reconnus comme représentant des facteurs limitant interdépendants. Pour cette raison, tout tentative de réduire la complexité peut venir au prix d’une dégradation substantielle du taux d’erreurs. Cette thèse traite de l’établissement d’un compromis limite fondamental entre la fiabilité et la complexité dans des systèmes de communications « outage »-limités à entrées et sorties multiples (MIMO), et ses scénarios point-à-point, utilisateurs multiple, bidirectionnels, et aidés de feedback. Nous explorons un large sous-ensemble de la famille des méthodes d’encodage linéaire Lattice, et nous considérons deux familles principales de décodeurs : les décodeurs à maximum de vraisemblance (ML) et les décodeurs Lattice. L‘analyse algorithmique est concentrée sur l’implémentation de ces décodeurs ayant comme limitation une recherche bornée, ce qui inclue une large famille de sphère-décodeurs. En particulier, le travail présenté fournit une analyse à haut rapport Signal-à-Bruit (SNR) de la complexité minimum (flops ou taille de puce électronique) qui permet d’atteindre a) une certaine performance vis-à-vis du compromis diversité-gain de multiplexage et b) une différence tendant vers zéro avec le non-interrompu (optimale) ML décodeur, ou une différence tendant vers zéro comparé à l’implémentation exacte du décodeur (régularisé) Lattice. L’exposant de complexité obtenu décrit la vitesse asymptotique d’accroissement de la complexité, qui est exponentielle en terme du nombre de bits encodés. / In telecommunications, rate-reliability and encoding-decoding computational complexity (floating point operations - flops), are widely considered to be limiting and interrelated bottlenecks. For this reason, any attempt to significantly reduce complexity may be at the expense of a substantial degradation in error-performance. Establishing this intertwined relationship constitutes an important research topic of substantial practical interest. This dissertation deals with the question of establishing fundamental rate, reliability and complexity limits in general outage-limited multiple-input multiple-output (MIMO) communications, and its related point-to-point, multiuser, cooperative, two-directional, and feedback-aided scenarios. We explore a large subset of the family of linear lattice encoding methods, and we consider the two main families of decoders; maximum likelihood (ML) based and lattice-based decoding. Algorithmic analysis focuses on the efficient bounded-search implementations of these decoders, including a large family of sphere decoders. Specifically, the presented work provides high signal-to-noise (SNR) analysis of the minimum computational reserves (flops or chip size) that allow for a) a certain performance with respect to the diversity-multiplexing gain tradeoff (DMT) and for b) a vanishing gap to the uninterrupted (optimal) ML decoder or a vanishing gap to the exact implementation of (regularized) lattice decoding. The derived complexity exponent describes the asymptotic rate of exponential increase of complexity, exponential in the number of codeword bits.

This study has been inspired by the political events in the past few years that signalled a general decline, instead of consolidation, of democracy in South Africa. The decline has caused a rising trust deficit between the government and the citizens of South Africa. These events have raised questions of the role of the media in the consolidation of democracy. Katrin Voltmer's pioneering work, The Media in Transitional Democracies (2013) shines an important light in delineating the role of the media in transitions, including democratic consolidation. Much of the focus of scholastic research in the subject of media and democracy has been on news and journalistic content. Jurgen Habermas' seminal work, The Structural Transformation of the Public Sphere (1989) also accorded more weight to the rational and cognitive, as opposed to the affective and emotive aspects of the media when arguing in favour of emancipatory potential of the public sphere. The rational and cognitive aspects are generally associated with news and journalistic content (McGuigan, 2005: 430). Unlike Habermas, this study follows the lead by scholars like Van Zoonen (2006) and McGuigan's (2005) interest in the popular entertainment content which has often been regarded as having little significance in politics, especially democracy. In its emphasis on the consolidation aspect of South African democratic transition, the study is conducted against the backdrop of the broader ‘third wave' transitions of the early 1990's (Huntington, 1991). The study's theoretical framework is aligned with Christians et al.'s (2009) revision of the Four Theories (Siebert, et al, 1956) of the press. Their approach is useful because of its normative strength that opens the possibilities of media roles in democratization. The normative approach allows a free exploration of the potential of the media, instead of restricting the media to the political systems within which they operate. In addition, it aligns itself to Jim McGuigan's theory of the cultural public sphere which highlights the often-ignored political potency of popular cultural texts in the public sphere. McGuigan (2005: 430) argues that the affective or emotive aspects of popular cultural texts enhance, rather than hinder, the quality of political engagement in the public sphere. Through entertainment television programmes, democratic ways of life can be portrayed as part of everyday, ordinary life (Stevenson, 2010: 276). Against the widely held expectation that the media should play a positive role in democracies, some scholars have noted that in reality, “this is not necessarily so” (Jebril, Stetka & Loveless, 2013: 3). Rather, the media can serve dictatorships as happily as they serve democracies (Voltmer, 2013: 23). Using the case studies of two soap operas of the South African Broadcasting Corporation (SABC), Muvhango and 7de Laan, the study explores the role of popular media in the enhancement or consolidation of democracy, and the circumstances under which this is carried out. The media of interest for this study is public service broadcasting (PSB). For most democracies of the third wave, especially in Africa, PSB has been an easy victim of political power. Because of its dependence on the state, PSB tends to be more susceptible to political interference than other media types. Like other PSBs, the SABC has clearly spelt-out objectives that are linked to the national developmental objectives, including the goal of promoting and deepening democracy. This connection makes it possible to evaluate the selected entertainment case studies against these objectives. The study uses Multimodal critical discourse analysis (MCDA) because it allows for the analysis of text in its multimodal form such as visuals and audio. It equally allows for the application of analytical tools borrowed from film and television theories. By indirect measurement, MCDA model is used in the study to evaluate how democracy is represented (promoted, negated, omitted) in various aspects of the text.

Purpose – The purpose of this master thesis is to generate new knowledge and understanding how the concept of public sphere has been used and understood in library and information research of public libraries.  Design/methodology/approach –Through a systematic literatur review of  research literature of public libraries and public sphere, interpretations of the public sphere concept are mapped. Qualitative content analysis is applied for the analysis. The research questions are: 1. How is the concept of public sphere interpretated in library and information science (LIS) research about the democratic role of the public library and its role beeing a meeting place and an arena for public debate?  2. What significance can the interpretation of the concept public sphere be assumed to have for the understanding of how LIS researchers view and use the concept?  Findings – Six themes are identified: 1. Habermas original theory of public sphere from 1962. 2. A theoretical framework of public sphere, based on Habermas theory. 3. Other concepts and theories that can be applied on public libraries and public sphere. 4. A diversity of public spheres. 5. The democratic role of the public libraries and public sphere. 6. Conversation, communication, debate and public sphere.

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