Mobiles is a composition for an ensemble consisting of 12 instruments. The piece, in one movement, incorporates intuition, chance, and twelve tone techniques and reflects the relationship between motion and rest or tension and release. The structure is modeled according to principles of growth and decay, starting off slowly, building, and then dying away. Much of the material is inspired by mental images invoked from modern theories concerning chaos. Mobiles' character stems from the principal use of two motives, the chaos motif and the echo motif. Primarily, the chaos motif is representative of a state of motion while the echo motif represents a state of rest. Mobile architecture is usually characteristic of symmetry, balance, and proportion, but because of uncertainty in a natural environment, this proportion often falls short of a perfect symmetrical balance as in the case of a crystal or a fractal design. It is this kind of architecture that Mobiles portrays in its form and developmental process.

I denna uppsats studeras Facebooks roll i politisk representation genom att se till huruvida det skapas en så kallad filterbubbla på Facebooks “Gilla-sidor”-sida. “Gilla-sidor”-sidan ger en Facebook-användare rekommendationer till nya sidor att gilla vilket räknas ut efter information om användaren. Informationen kan härstamma från det användaren har delgett Facebook via personlig information eller sidor som användaren tidigare har gillat och interagerat med. Rekommendationerna kan även påverkas av vänner på Facebook samt genom att surfa på andra hemsidor. Dessa två påverkansfaktorer har dock lämnats utanför denna studie och fokus ligger således på de två förstnämnda faktorerna. Studien tar förutom teorin om filterbubblan upp teorier som cyberbalkanisering, echo chamber och selektiv exponering för att förklara hur information kan påverka och påverkas av människors val på internet. Studien diskuterar resultat i ljuset av de stora konsekvenser som information har på medborgare och samhället i stort. Experimentdelen i studien innefattar skapandet av olika personas, eller fiktiva användare, på Facebook. Genom statistik har en så högt representerad medelanvändare som möjligt återskapats. Dessa användare har sedan interagerat med politiska partier. Sedan studeras Facebooks “Gilla sidor”-sidan med en kvantitativ innehållsanalys för att se vad som studsar tillbaka på användaren utifrån den genomförda interaktionen. Centralt i denna undersökning är att förstå den globala debatt om Facebooks roll som politiskt avgörande i det amerikanska presidentvalet som skedde samtidigt som studien genomfördes. Vid studiens startpunkt var filterbubblan något som diskuterats inom forskarvärlden och bland insatta medie-intresserade. När presidentvalet var avgjort kulminerade diskussioner om Facebooks roll som desinformatör genom att falska nyheter spreds för att påverka väljare i olika riktningar. Det fick till följd att Facebooks VD Zuckerberg gick ut med att nya lösningar skulle implementeras för att stävja detta utan att specificera hur. Denna studie har kunnat se förändringar på “Gilla sidor”-sidan som kan få konsekvenser för den politiska debatten på Facebook. Dessa förändringar har däremot inte på något sätt kommunicerats ut av Facebook. Därför tar denna studie även upp problematiken i att studera sociala medier online och efterfrågar en större transparens och förståelse för hur Facebook agerar. Resultaten analyseras utifrån två undersökningstillfällen som visar att Facebook tidigare har lyft upp politiska sidor för användare i hög utsträckning men numera skapar en mer lokalt förankrad “Gilla sidor”-sida. Författarna drar slutsatser om att Facebook i det första undersökningstillfället tydligt politiserade en politiskt aktiv användare medans en icke-politisk person inte tog del av politiska sidor i lika hög utsträckning. Studien visar även att en filterbubbla skapats utifrån blockpolitiska preferenser där mer likgiltig politisk information presenterades för en persona utifrån politiska block. Slutstatser kan dras om att förändringen som studien presenterar kommer få konsekvenser för den roll som Facebook spelat som politiskt samlingsplats. Även om studien enbart fokuserar på en plats på nätverket kan de förändringar som pekas på i uppsatsen göra plattformen till mindre politiskt engagerande hos användare och således få konsekvenser för politisk diskussion i Sverige och potentiellt världen. / This paper is about Facebook’s role in political representation. The goal of the study is to examine the occurrence of filter bubbles on Facebook’s  recommendations-page. This page is called “Like pages” and provides Facebook-users with recommendations of new pages to like and is created by algorithms that take into account personal information of the user, which pages the user has liked earlier, friends on the network and other websites the user has visited. The two latter factors however have been left aside in this study, which focuses instead on personal information and interaction with Facebook-pages.                       Besides the filter bubble-theory, this paper includes theories about “cyberbalkanization”, “echo chambers” and “selective exposure” in order to explain how information can influence and is influenced by people’s choices on the internet. The results of this research are discussed in the light of the large consequences which information has on internet users and society in general.                       The experimental part of the study includes the creating of six fictitious Facebook-profiles with help of several statistics, in order to make the profiles as representative as possible. Those profiles then interact with different political pages from Sweden. That has an impact on the recommendations-page, which subsequently is studied with help of a quantitative content analysis to see what content the user gets back, based on her earlier interactions.                       A central aim of this paper is to understand the global discussion about Facebook’s role as a political influencer in the US-election 2016, which has taken place during the same period of time as this paper has been written. When beginning this research, “filter bubbles” was something that was discussed in science and among media-interested. After the results of the election were final, the discussions about Facebook’s role as a propagator of fake-news culminated and the company was accused to have influenced voters. As a reaction to this, Facebook’s CEO Zuckerberg announced the company will find ways for stopping the distribution of fake-news on Facebook. Those consequences are already visible in this research and possible consequences on a political debate on Facebook are discussed. However, the changes that have been made on Facebook have not been communicated publicly in any way by the company. For this reason this study also discusses problems that can occur studying online-content and makes demands on a higher transparency of how Facebook’s algorithms work.                       The analysis of the results show that Facebook before the changes has recommended its users pages with political content in a much higher extent than after the change, when the recommendations-page is mainly based on local-fixed Facebook-pages. The authors draw the conclusion that Facebook, before the changes, politicized a political active user, while a political inactive user is not presented for political material in the same extent. Even a filter bubble could be observed, based on block-political preferences of the user. The authors agree upon that the changes, Facebook made will have an impact on Facebook’s role as a political forum. Even if this study only focuses on the recommendations-page on Facebook, the changes that Facebook made can make Facebook to a less political platform and potentially affect the democracy in Sweden and all around the world.

Das Signal-zu-Rausch-Verhältnis (SNR) stellt bei modernen Bildgebungstechniken in der Magnetresonanz-Tomographie heutzutage oftmals die entscheidende Limitation dar. Eine Verbesserung durch Modifikation der Hardware ist kostspielig und führt meistens zu einer Verstärkung anderer Probleme, wie zum Beispiel erhöhte Energiedeposition ins Gewebe. Im Gegensatz dazu ist Dichtegewichtung eine Methode, die eine SNR-Erhöhung durch Modifikation der Aufnahmetechnik ermöglicht. In der MR-Bildgebung erfolgt oftmals eine retrospektive Filterung des aufgenommenen Signalverlaufs, beispielsweise zur Artefaktreduktion. Damit einhergehend findet eine Veränderung der Modulationstransferfunktion (MTF) bzw. ihrer Fouriertransformierten, der räumlichen Antwortfunktion (SRF), statt. Optimales SNR wird nach dem Matched Filter-Theorem erzielt, wenn die nachträgliche Filterung dem aufgenommenen Signalverlauf proportional ist. Dies steht dem Ziel der Artefaktreduktion entgegen. Bei Dichtegewichtung steht durch nicht-kartesische Abtastung des k-Raums mit der k-Raum-Dichte ein zusätzlicher Freiheitsgrad zur Verfügung. Dieser ermöglicht es, im Falle eines konstanten Signalverlaufs eine gewünschte MTF ohne Filterung zu erreichen. Bei veränderlichem Signalverlauf kann ein SNR Matched Filter angewendet werden, dessen negative Einflüsse auf die MTF durch Dichtegewichtung kompensiert werden. Somit ermöglicht Dichtegewichtung eine vorgegebene MTF und gleichzeitig ein optimales SNR. In der vorliegenden Arbeit wurde Dichtegewichtung erstmals bei den schnellen Multi-Echo-Sequenzen Turbo-Spin-Echo und Echoplanar-Bildgebung (EPI) angewendet. Im Gegensatz zu bisherigen Implementierungen muss hier der Signalabfall durch T2- bzw. T2*-Relaxation berücksichtigt werden. Dies führt dazu, dass eine prospektiv berechnete dichtegewichtete Verteilung nur bei einer Relaxationszeit optimal ist. Bei Geweben mit abweichenden Relaxationszeiten können sich wie auch bei den kartesischen Varianten dieser Sequenzen Änderungen an SRF und SNR ergeben. Bei dichtegewichteter Turbo-Spin-Echo-Bildgebung des Gehirns konnte mit den gewählten Sequenzparametern ein SNR-Vorteil von 43 % gegenüber der kartesischen Variante erzielt werden. Die Akquisition wurde dabei auf die T2-Relaxationszeit von weißer Substanz optimiert. Da die meisten Gewebe im Gehirn eine ähnliche Relaxationszeit aufweisen, blieb der visuelle Gesamteindruck identisch zur kartesischen Bildgebung. Der SNR-Gewinn konnte in der dichtegewichteten Implementierung zur Messzeithalbierung genutzt werden. Dichtegewichtete EPI weist eine hohe Anfälligkeit für geometrische Verzerrungen, welche durch Inhomogenitäten des Hauptmagnetfeldes verursacht werden, auf. Die Verzerrungen konnten erfolgreich mit einer Conjugate Phase-Methode korrigiert werden. Dazu muss die räumliche Verteilung der Feldinhomogenitäten bekannt sein. Dazu ist zusätzlich zur eigentlichen EPI-Aufnahme die zeitaufwendige Aufnahme einer sogenannten Fieldmap erforderlich. Im Rahmen dieser Arbeit konnte eine Methode entwickelt werden, welche die zur Erlangung einer Fieldmap notwendige Aufnahmedauer auf wenige Sekunden reduziert. Bei dieser Art der Fieldmap-Aufnahme müssen jedoch durch Atmung hervorgerufene Effekte auf die Bildphase berücksichtigt werden. Die Fieldmap-Genauigkeit kann durch Aufnahme unter Atempause, Mittelung oder retrospektiver Phasenkorrektur erhöht werden. Für die gewählten EPI-Sequenzparameter wurde mit Dichtegewichtung gegenüber der kartesischen Variante ein SNR-Gewinn von 14 % erzielt. Anhand einer funktionellen MRT (fMRI)-Fingertapping-Studie konnte demonstriert werden, dass die SNR-Steigerung auch zu einer signifikant erhöhten Aktivierungsdetektion in Teilen der Hirnareale führt, die bei der Fingerbewegung involviert sind. Die Verwendung von zusätzlicher EPI-Phasenkorrektur und iterativer Optimierung der dichtegewichteten k-Raum-Abtastung führt zu weiteren Verbesserungen der dichtegewichteten Bildgebung mit Multi-Echo-Sequenzen. / Magnetic resonance imaging (MRI) is often limited by the signal to noise ratio (SNR). In standard Cartesian acquisition methods, the SNR can be improved by applying a so-called matched filter to the acquired raw data, which correlates with the anticipated signal profile. Unfortunately, this filter changes the spatial response function (SRF), which characterizes the imaging properties of the imaging method, in an undesired way. For example, a matched filter often amplifies undesired image artifacts and is thus normally omitted. In contrast, filters which change the SRF are typically applied, e.g., for artifact reduction. These however do not provide an optimal SNR. Density weighting is a method which allows a desired SRF and an optimal SNR at the same time. This is achieved by introducing a new degree of freedom to the SRF; the density of the acquisition steps in k-space. In this work, density weighting was adapted to turbo spin echo (TSE) and echo planar imaging (EPI). In contrast to earlier implementations of density weighting, signal relaxation has to be taken into consideration with these multi-echo sequences. As a result, the desired SRF and SNR are only obtained for one prospectively determined relaxation time. For deviating relaxation times, changes in SRF and SNR may occur. In density weighted TSE brain imaging, an average SNR gain of 43 % over Cartesian imaging could be achieved for the chosen sequence parameters. The density weighted acquisition was optimized for the T2 relaxation time of white matter. Since the relaxation times of most other tissues in the brain did not significantly differ, the overall visual impression of density weighted and Cartesian images was identical. The achieved SNR gain could be used to halve the acquisition time of the density weighted implementation. Density weighted EPI is especially prone to geometric distortions caused by inhomogeneities of the main magnetic field. The distortions could be successfully corrected with a conjugate phase method. For these methods, a time-consuming acquisition of a so-called field map is typically required. A method could be developed which greatly reduces the field map acquisition time to a few seconds. It was found that phase changes caused by respiration influence the field map accuracy of this and similar methods. A significantly higher accuracy could be achieved by an acquisition under breath-hold or by retrospective phase correction or averaging. It was demonstrated in an fMRI group study that an average SNR gain of 14 % for density weighted EPI resulted in an increased detection power in the activated brain areas. First results involving additional EPI phase correction and iterative k-space sampling optimization demonstrate further improvements of density weighted imaging with multi-echo sequences.

Graduation date: 1984

The issue of dative alternation construction has long been a debated topic in the linguistics field. This thesis especially focuses on the grammatical weight interpretation. Quirk et al. (1972) stated the end-weight rule, which predicted that people tended to put the NP which is heavier at the final position of a sentence. However, how to define the heaviness of NP is still in debate. Ross (1967) claimed that an NP is heavy if it dominates ¡§a sentence¡¨. Emonds (1976: 112) argued that an NP is called as heavy in the complex NP shift is that the NP dominates an S or PP. On the other hand, Hawkins (1990, 1994) proposed the idea that the heaviness is determined by the number of words dominated by a NP. Therefore, this thesis tries to shed some light on the precise definition of grammatical weight for Chinese native speakers. Secondly, Chang (2001) argued that the echo effect was prominent for Chinese native speakers to determing the dative word order variation. The subjects tended to echo the question pattern when they responded to that question. Hence, this thesis also tries to investigate the phenomenon when the echo effect issue meets with the grammatical weight interpretation. Judgment task, contextual questions task and corpus analysis are adopted in this study. Contextual questions task tries to investigate the subjects¡¦ response to a contextual question which contains dative verbs. The purpose of this contextual questions task is to know when the complexity effect meets with the echo effect, what is more determining. The judgment task tests the participants¡¦ judgment on the grammaticality of sentences which contains dative alternation. The purpose of this questionnaire is to see if the complexity of a NP contributes to the determining of a dative alternation construction. The corpus used is Chinese Word Sketch corpus developed by Academia Sinica. There are 253 sentences in total. I try to consider the length of the constituents and the complexity of constituents in dative alternation. In the first section of the questionnaire, the result shows that the Chinese native speakers are both sensitive to the echo effect and the complexity effect. Besides, the preference for the dative sentence type is also found based on the result. In the second section of the questionnaire, the result indicates that the Chinese native speakers are indeed sensitive to the complexity of a NP. The subjects tend to rate the sentences which contains a more complex NP at the final position of a sentence more acceptable than that at the middle of a sentence. In addition, the preference of the dative sentence type is also found in the result. In the corpus study, the results show that subjects are both sensitive to the complexity of constituents and length of constituents. In conclusion, the Chinese native speakers in this study shows sensitivity to both the complexity effect, length effect and echo effect. Furthermore, in both questionnaires, the preference for the dative sentence type is identified. This preference can be explained through the unmarked property of the dative sentence type in Chinese.

The myth, Echo and Narcissus, is retold in a modern context in my play Jinx Infinity. The accompanying exegesis examines the techniques I employed in writing this piece with reference also to two other plays I have written from myth. This exploration seeks to determine the fine balance between focusing or relying on the myth and the actuality of writing a dramatic text to be performed on stage by actors in front of a live audience. I was able to divide the results from the examination of my writing process into a ten-step guideline or template. The question of balance is addressed throughout the guidelines but becomes particularly vital in the final step, when the playwright is advised to forget the myth in order to ensure the established principles of playwriting are adhered to. If these principals are present and the essence of the ancient myth is inherent, then the final product should be a successful play containing a universal theme that will translate through the ages.

Thesis (Ph.D.) - University of St Andrews, May 2008.

Thesis (Ph. D.)--University of California, San Diego, 1972. / Vita. Includes bibliographies.

Techn. University, Diss., 2003--Berlin.

Proefschrift Rijksuniversiteit Groningen. / Auteursnaam op omslag: Daan Thorn Leeson. Datum laatste controle: 22-12-1997. Lit.opg. - Met samenvatting in het Nederlands.